Abstract:The degree of cadmium damage to kidney in mice and the protective effect of theacrine on kidney under different doses were studied. In the research, the model of oxidative damage of kidney tissue in mice was established by intraperitoneal injection of cadmium chloride. Fifty male Kunming mice were randomly divided into blank group, injury group and low, medium and high dose protection group, with 10 mice in each group. The blank group and model group were given normal saline of equal volume by gastric perfusion, in the protective group were given theacrine suspension of 10 mg/kg, 20 mg/kg, 40 mg/kg by gastric perfusion. After 14 days of treatment, cervical dislocation was performed and kidney tissues were taken out. The contents of lipid peroxidation (MDA), protein carbonylation (PCO), nitric oxide (NO), catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) in the kidney were detected. The pathological changes of nephropathy were observed. The results showed that compared with the blank group, the contents of MDA, PCO and NO in the kidney tissue of the model group increased significantly (p<0.01), which were 1.89, 3.32 and 1.64 times content of the blank group respectively, while the activities of SOD, CAT and GSH decreased significantly (p<0.01), only 76.25%, 77.12% and 45.61% of the blank group respectively. Compared with the model group, the protective group reduced the contents of MDA, PCO and NO, increased SOD, CAT and GSH activities, and reduced the degree of kidney injury. Pathological sections showed that middle dose of theacrine had the best protective effect on kidney injury. The results showed that theacrine had protective effect on cadmium-induced renal injury in mice. It can effectively reduce the degree of oxidative damage and maintain the balance between enzymes and antioxidant enzymes. The mechanism may be related to antioxidant activity.

Abstract:The ameliorating effects of Bifidobacterium longum DD98 on high fat diet-induced type 2 diabetes mice and obesity in mice were investigated. Type 2 diabetes experiments: C57BL/6N mice were randomly divided into four groups (6 rmice per group): the normal chow group given a normal chow diet; the model control group, Bifidobacterium longum DD98 intervention group, and blank culture medium intervention group fed a high-fat diet. After four weeks, model mice with diabetes was established using streptozotocin (STZ). The mice were given the tested samples for 3 weeks, before glucose tolerance test and measurements of various indicators. Compared with the of the model group and the blank culture medium intervention group, the DD98 intervention group had a significantly decreased fasting blood-glucose (FBG) (18.66±1.84 mmol/L), along with significantly improved glucose tolerance and reduced serum/liver total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels. Obesity experiments: C57BL/6N mice were randomly divided into four groups (6 rmice per group): the normal chow group given a normal chow diet; the model control group, Bifidobacterium longum DD98 intervention group, blank culture medium intervention group with a high-fat diet. After five weeks of treatments, various indicators were measured. Compared with the high-fat diet group and the blank culture medium intervention group, the DD98 group had significantly lowered fasting body weight (20.89±2.51 g) and serum/liver TC, TG and LDL-C levels with significantly reduced fat accumulation in the liver. Therefore, Bifidobacterium longum DD98 could effectively ameliorate the symptoms of type 2 diabetes and obesity, and further alleviate dyslipidemia caused by type 2 diabetes and obesity, and liver injury caused by obesity.

Abstract:Preliminary study was conducted on the mechanism underlying the anti-anemia function of an aqueous extract of Hibiscus sabdariffa L. (HS). The IDA rat model was established and the resulting rats were randomly divided into 4 groups. The IDA rats were administered with low, medium and high doses of HS. After 30 days, the rats were dissected and their duodenum and liver were taken. Then, Q-PCR and Western blot techniques were used to detect the expression levels of divalent metal transporter 1 (DMT-1), ferroportin (FPN), hephaestin (Hp) and their mRNA in the duodenum as well as the expression of hepcidin and its mRNA in the liver of the rats. The results showed that the decreases in the expression levels of DMT-1, FPN-1 and Hp for the low and medium HS dose groups were not more than 9%, while the mRNA expression level were over 50%, compared with those of low-iron control group. There were no significant difference in Hp mRNA between the low dose and medium dose groups. The decreases in the expression of DMT-1, FPN-1, Hp and their mRNA induced by the high-dose HS varied. The expression level of Hepcidin-25 in the low-dose group was 1.61 times as high as that for the low-iron control group, whilst the expression level in the high-dose group decreased by 65.79%. HS at different doses all showed an inhibitory effect on the mRNA expression. Therefore, HS promotes the absorption of iron in the body by providing active constituents, thereby affecting the expression of DMT-1, FPN-1, Hp, Hepcidin-25 and its mRNA in IDA rats, to maintain the iron homeostasis inside the body.

Abstract:To explore the effect and mechanism of ethanol extract of Hericium erinaceus on apoptosis of gastric cancer cells in rats. Sixty SD rats were selected, 10 as normal group, and the remaining 50 as gastric cancer models. They were divided into gastric cancer group, drug control group, low, medium and high concentration group of Monkey mushroom fungus. The cell proliferation, apoptosis and cycle distribution were observed, and the expressions of motilin, gastrin, Bcl-2, Bax and caspase-3 were detected. The results show that: The levels of motilin and gastrin in the high concentration group were 140.62 pg/mL and 85.39 pg/mL respectively, the apoptotic rate of tumor cells was 50.25%, the percentage of cells in G1 phase was 55.61% and the expression of Bax was 0.76, it was higher than that of gastric cancer group, drug control group, low and medium concentration of Hericium erinaceus groups. The proliferation rate of tumor cells in the high concentration group of Hericium erinaceus was 11.52%, The expressions of Bcl-2 and caspase-3 were 1.35 and 1.32 respectively, they were lower than those of gastric cancer group, drug control group, low and medium concentration of Hericium erinaceus groups (p<0.05). Ethanol extract of Hericium erinaceus can improve the gastric function of gastric cancer rats, regulate the proliferation, apoptosis and cycle distribution of gastric cancer cells, and provide a theoretical basis for clinical treatment of gastric cancer.

Abstract:The model of rats suffering from chronic, mild and unpredictable stress was used to explore the potential mechanism underlying the anxiety symptoms-alleviating effect of an aqueous extract of Semen Ziziphi Spinosae. Using reference indices associated with behaviors (sucrose preference rate, open field score, and time spent in the dark zone) and the intestinal flora, the effects of the aqueous extract of Semen ZiziphiSpinosae on the behaviors, and intestinal flora diversity, structure and composition in anxious model rats were studied. The results showed that compared with the model group (CUMS) group, chronic administration of Semen Ziziphi Spinosae significantly ameliorated chronic stress-induced aanxiety-like behaviors in rats (sugar water preference rate and open field score increased significantly, while the time spent in the dark box significantly decreased). The alpha diversity of the intestinal flora for the SZS group significantly increased (p<0.05), with the flora structure of the SZS group significantly different from the CUMS group. Further investigation revealed that the SZS group had significantly lower abundance of Lactobacillus (CUMS: 29.42%; SZS: 8.08%; p=0.003) and Ruminococcaceae_UCG-014 (CUMS: 3.30%; SZS: 2.14%; p=0.04), but higher abundance of Bacteroides (CUMS: 2.23%; SZS: 5.15%; p=0.001), norank_o_Mollicutes_RF9 (CUMS: 1.01%; SZS: 2.43%; p=0.019), Ruminiclostridium_9 (CUMS: 0.42%; SZS: 0.62%; p=0.034), Parabacteroides (CUMS: 0.35%; SZS: 0.60%; p=0.011), Butyricimonas (CUMS: 0.01%; SZS: 0.03%; p=0.018) and Acetatifactor (CUMS: 0.01%; SZS: 0.03%; p=0.001), compared with the CUMS group. These results indicated that Semen Ziziphi Spinosae could alleviate the anxiety-related symptoms in CUMS rats and affect their intestinal flora structure, which provides a theoretical basis for the potential working mechanism.

Abstract:In order to explore the improvement effect of Lycium barbarum extract on the symptoms of osteoporosis, this paper discussed the improvement effect of Lycium barbarum extract on the symptoms of osteoporosis in rats through experiments, according to the increase and decrease of the concentration and various indexes of Lycium barbarum extract. Eighty female rats meeting the requirements were divided into two groups, one group for removing ovarian surgery to build osteoporosis rats model. Different concentrations of Chinese wolfberry extract extracted with the use of water, and physiological saline were gavaged to rats, the related indicators were examined 70 d after the death of rat. The results showed that the Lycium barbarum extract could effectively improve the bone mineral density of osteoporosis rats up to 0.05 g/cm, conversion growth factor-beta 1 to 28.15 μg/mL, nitric oxide to 7.05 μmol/L, nitric oxide synthase to 8.23 U/mL, phosphorus ion to 0.05 mmol/L, and osteocalcin to 0.13 nmol/mL. Lycium barbarum extract can effectively reduce the serum calcium ion to 0.15 mmol/L, magnesium ion to 0.10 mmol/L, alkaline phosphatase to 13.17 U/L, immunoregulatory factor interleukin-6 to 12.75 ug/mL and tumor cell necrosis factf-alpha tot 1.06 ug/mL in rats with osteoporosis. Moreover, the concentration of Lycium barbarum extract increased inversely with the decrease of various indexes. It is concluded that Lycium barbarum extract can effectively regulate the cytokines in the body of osteoporotic rats, alleviate the osteolysis of rats, and achieve the goal of treating osteoporosis.

Abstract:The preventive effect of the extract of Chaenomeles speciosa (Sweet) Nakai (CS) on nonsteroidal anti-inflammatory drug (NSAID)-induced intestinal injuries in mice were investigated, mice were given the CS by intragastric administration for 6 days, and then the diclofenac sodium (5 mg/mL) was given to the stomach for 2 consecutive days on the 5th day to intestinal mucosal lesions were observed Expression levels of glucose transporter protein 78 (GRP-78), tumor necrosis factorα (TNF-α), Toll receptor 4 (TLR4), chop and NLRP were detected. The results of FITC-DT showed that the relative fluorescence value (RFU) of the normal group was 682.7±105.4, with 2008.3±496.1, 1097.8±501.1 and 737.5±275.5 for the model group , low CS dose group, and high CS dose group, respectively. Compared with the normal group, the extent of the small intestinal mucosal injury and permeability for the model group significantly increased. Compared with the model group, different CS doses could significantly reduce the small intestinal mucosal injury in mice, with the mechanism associated with the regulation of the endoplasmic reticulum stress (GRP78 and CHOP) and reduction of intestinal inflammation (TLR4 and TNF-α) by CS. These findings suggest that CS can prevent the damage of the small intestinal mucosa caused by NSAID in mice through regulating the TLR4-endoplasmic reticulum stress.

Abstract:A method for the determination of chlorogenic acid and hesperidin in Fufang Shanzha was established in this work. And compare the content of active ingredients in Fufang Shanzha prepared by different solvents (ethanol and water) and their digestive promotion effect was investigated. The contents of chlorogenic acid and hesperidin were determined by HPLC. The comprehensive score was carried out based on their content and paste-forming rate. According to the principles offunctional food, the acute toxicity, the distance of ink movement in small intestine in mice, the body weight, food intakes, food efficiency ratio and the secretion amount of gastric juice and pepsin activity were evaluated. The results showed that the comprehensive score of active ingredients of water extraction (93.78) was higher than ethanol extraction (80.04). Water extraction and ethanol extraction had no acute toxicity to mice and rats. All of them could significantly increase the food intake of rats (p<0.05). The small intestine movement rates in middle dosage, high dosage group of water extraction and high dosage group of ethanol extraction increased by 26.88%, 28.00%, 26.55% (p<0.05, p<0.01, p<0.05), respectively. In addition, the secretion of pepsin in rats in middle dosage, high dosage group of water extraction and high dosage group of ethanol extraction increased by 38.59%, 53.29%, 36.64% (p<0.05, p<0.01, p<0.05), respectively. However, there was no significant difference in small intestinal movement rates and pepsin excretion of rats in other dose groups of ethanol extraction (p≥0.05). The activity of pepsin increased by 75.96%, 125.07%, 70.38%, 109.38% (p<0.05, p<0.01, p<0.05, p<0.01) in the middle dosage, high dosage group of water extraction and ethanol extraction, respectively. For the content of active ingredients and the digestive promotion effect, the water extract from Fufang Shanzha was superior to the ethanol extract.

Abstract:The effect of vitamin D on lipid metabolism in obese rats was investigated. Obesity rat model was established. The rats were divied into normal group, model group, high dose group (2.40 μg/mL), medium dose group (1.20 μg/mL), low dose group (0.60 μg/mL) and orlistat group (0.10 mg/mL). The body weight, body length, Lee's index, epididymal fat pad mass and fat body mass index were evaluated. Total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL-C), low density lipoprotein (LDL-C) and the morphology of rat adipocytes were detected. Peroxisome proliferator-activated receptor gamma (PPAR-gamma), leptin and mitochondrial uncoupling protein (UCP) protein expression were also detected. The weight of rats, Lee's index, the weight of epididymal fat pad, fat body mass index, TC, TG, LDL-C and HDL-C in high dose group were 250.76 g, 2.52%, 5.05 g, 1.41 g, 1.96 mmol/L, 0.83 mmol/L, 1.05 mmol/L (lower than that in model group), and 0.59 mmol/L (higher than that in model group, p<0.05), respectively. The expression of PPAR-gamma and leptin in the high dose group was lower than that in the model group, and the expression of UCP in the high dose group was higher than that in the model group (p<0.05). Vitamin D can improve lipid metabolism in rats by regulating the expression of PPAR-gamma, leptin and UCP.

Abstract:In this study, wheat bran was modified by microwave irradiation combined with composite enzymatic treatment, and the improved wheat bran was added to the high-gluten wheat flour to obtain wheat bran-containing flour with different contents of wheat bran for the preparation of bran-containing breads. The results revealed that the residual lipase and lipoxidase activities in the improved wheat bran decreased to 0 and 10.34%, respectively, with the crude fiber content decreasing to 3.21% and the reducing sugar content increasing to 3.79 g/100 g. Compared with the unmodified whole wheat bread, the modified whole wheat bread incorporated with different levels of improved wheat bran had an improved bread crumb structure, a decreased (by 14.70%) endothermal enthalpy after 7 days of storage, increased contents of ketone, carbonyl and aldehyde groups, increased specific volume (by 26.40%) , decreased hardness (by 32.90%), and increased elasticity (by 6.90%). With an increasing amount of improved wheat bran for addition, the structure of the bran-containing bread became rough and porous, the bread endothermal enthalpy decreased gradually, the contents of ketone, carbonyl and aldehyde groups in the bread increased, causing a lowered sensory quality (darker bread, lower specific volume, higher hardness and lower elasticity) . Compared with the whole wheat bread with 16% of unstabilized wheat bran, the whole wheat bread incorporated with stabilized wheat bran had improved stability, storage properties and texture.

Abstract:Twenty-six suspected lactic acid bacteria were isolated from naturally-fermented sauce of Monetaria moneta. After colony morphology, bacterial morphology, physiological and biochemical experiments and 16S rDNA identification, Lactobacillus plantarum and Tabacillus pentosae strains No. 3 and No. 6 were identified as Lactobacillus plantarum and Tabacillus pentosae respectively. The growth curve, acid production capacity, acid tolerance and salt tolerance of the two strains were investigated. The results showed that the two strains began to enter logarithmic growth phase after 6 hours, strain 3 and strain 6 entered stable phase after 18 hours and 20 hours, respectively. The growth rate of strain 3 was faster than that of strain 6, and the OD value of strain 3 reached about 1.73 and that of strain 6 reached about 1.56 after entering the stable stage. After 6 hours, the acid production rate of the two strains accelerated, and after 20 hours, the acid production capacity of strain 3 became stable, and the acid production capacity of the two strains was strong at pH 3.5. Both strains could tolerate 3%~4% of salt, and strain 6 had a slightly stronger salt tolerance than strain 3.

Abstract:Jiashi melon was chose as experimental material. Non-invasive inoculation methods of melon with Alternaria alternata was used. The objective of this study was aimed to compare the resistance difference of no-netted, small-netted and large-netted pericarp to pathogenic bacteria during storage. The relationship between reactive oxygen species (ROS) metabolism and key enzymes activity was investigated. The results showed that, when Jiashi melon was infected by Alternaria for 30 days, the incidence of disease rates of non-netted group, small-netted group and large-netted group were 77.77%, 84.17%, 88.02%, espectively. The superoxide radical (O2·-) production rate and Glutathione (GSH) content of each experimental group increased firstly and then decreased. The content of hydrogen peroxide (H2O2) increased firstly, then decreased, and increased during storage. The content of Malondialdehyde (MDA) of exocarp increased firstly and then decreased. However, the content of MDA of endocarp increased continuously. The O2·- production rate, GSH, H2O2 and MDA content of exocarp were higher than that of endocarp during the infection period. The activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and glutathione reductase (GR) of each experimental group increased firstly and then decreased. Themaximum of SOD activity in no-netted, small-netted and large-netted of exocarp were 49.19 U, 39.29 U and 31.81 U, respectively, and that of endocarp were 32.36 U, 24.28 U and 19.30 U, respectively. The maximum of CAT activity in no-netted, small-netted and large-netted of exocarp were 485.95 U, 393.68 U and 220.40 U, respectively, and that of endocarp were 202.67 U, 228.30 U and 137.93 U, respectively. The maximum of POD activity in no-netted, small-netted and large-netted of exocarp were 28.62 U, 24.84 U and 23.13 U, respectively, and that of endocarp were 14.46 U, 9.73 U and 8.58 U, respectively. The maximum of GR activity in no-netted, small-netted and large-netted of exocarp were 378.32 U, 170.24 U and 196.15 U, respectively, and that of endocarp were 70.58 U. 45.61 U and 66.67 U, respectively. Ascorbate peroxidase (APX) activity increased continuously during storage. APX activity of exocarp was higher than that of endocarp. APX activity of no-netted group was higher than that of small-netted group and large-netted group. In conclusion, the postharvest disease resistance of Jiashi melon pericarp was closely related to the metabolism of ROS. The disease resistance of exocarp was stronger than that of endocarp. The disease resistance in no-netted group was stronger than that of small-netted group and large-netted group.

Abstract:Ribonucleic acid exonuclease R (RNase R) can degrade almost all the linear RNA molecules and Y-structured RNAs, but does not readily degrade circRNAs, lariat RNAs and double-stranded RNA molecules with less than 7 nucleosides Therefore, intron cDNA library can be constructed for the intron splicing variable research. In this study, a recombinant expression plasmid pET-22b(+) -rnr containing RNR gene was constructed. The expression product was purified and analyzed by SDS-PAGE while the enzyme activity was also determined to confirm that the rnr gene has been expressed in E. coli. Then, four molecular chaperone co-expression systems (pGro7, pKJE7, pTf16 and pG-Tf2) were constructed. The four molecular chaperone plasmids were co-expressed respectively with the recombinant expression plasmid pET-22b(+)-rnr. The optimal molecular chaperone plasmid was screened and the co-expression conditions were optimized to improve the soluble expression of the target protein. The results showed that the molecular chaperone plasmid pGro7 was the most effective and could increase the expression of protein by 43.80%, with the soluble expression of the target protein reaching the highest at an inducing temperature of 20 ℃. When the concentration of L-arabinose was 0.50 mg/mL, the molecular chaperone plasmid pGro7 increased the expression of protein by 54.50%. The soluble expression of RNase R could be improved by using the molecular chaperone co-expression system and optimizing the expression conditions, which laid a foundation for further study of RNase R.

Abstract:In order to investigate the effects of nitric oxide (NO) treatment on ethylene metabolism in postharvest fresh lotus seeds, the fresh “Space Lotus No. 36” lotus seedpods were treated firstly with different concentrations of NO, before storage at (25±1) ℃. The optimal concentration of NO was screened through analyzing the color difference and phenotype of lotus seedpods and seeds. On this basis, the effects of NO treatment on the respiration of fresh lotusseed pods, and the quality and ethylene metabolism of lotus seeds were studied. The results showed that the treatment with NO at 0.25 mmol/L significantly maintained the qualities of lotus seedpods and seeds, significantly slowed down the decreases of soluble sugar and starch in the lotus seeds, and inhibited the respiration rate of lotus seedpods from the 2nd to 4th day (while enabling the release of ethylene over 19.93% after 4 days) inhibited the accumulation of 1-aminocyclopropane-1-carboxylic acid (ACC) in lotus seeds. Meanwhile this NO treatment inhibited the activities of ACC synthetase (ACS, over 46.72% after 4 days) and ACC oxidase (ACO, over 14.79% during day 2~4) in the lotus seeds, while maintaining a relatively high methionine (Met) content in lotus seeds (but exerting insignificant effect on the content of s-adenosine methionine (SAM)). Therefore, this NO treatment prolonged the shelf life of lotus seedpods and seeds by 2~3 days. In conclusion, NO treatment can inhibit effectively preserve the quality of lotus seeds and inhibit the synthesis of ethylene in lotus seeds, thereby delaying the senescence of lotus seedpods and seeds. This study provides theoretical and technical support for the postharvest preservation of fresh lotus seedpods and seeds.

Abstract:In this study, 10 strains of bacteria were isolated from the culture water collected from the Penaeus vannamei shrimp farms, subjected to molecular identification and phylogenetic tree analysis, and evaluation of their inhibitory effects on Anabaena cylindrica FACHB-82. The 16S rRNA gene analysis showed that three strains resembled the most Pseudomonas (P. plecoglossicidc, P. protegens and P. monteilii), with one strain similar to Aeromonas veronii, two similar to Thauera mechernichensis and Thauera aromatica, one similar to Bacillus subtilis, one similar to Microbacterium flavum, one similar to Flavobacterium cauense, and one similar to Chryseobacterium nakagawai. Bacterial strain AB-3 exhibited the greatest inhibition, with a rate of 87.11% against Anabaena cylindrica FACHB-82. In addition, AB-3 had inhibition rates of 79.89% and 23.65% against Aphanizomenons flos-aquae and Microcystis aeruginosa, inhibited chlorella vulgaris to some extent, but exerted insignificant inhibitory effect on Chlamydomonas reinhardtii. In this study, the Taueus strain, AB-3, isolated from the culture water had a significant algicidal effect on the cyanobacteria, whilst no or little inhibitory effect on chlorella.

Abstract:Two main polysaccharide fractions (RSPs-40 and RSPs-60) were isolated from Rosa sterilis fruit by hot water extraction and fractional alcohol precipitation, respectively. The physicochemical characteristic, antioxidant and α-glucosidase inhibition activity of RSPs-40 and RSPs-60 were investigated. The results showed that the extraction yields of RSPs-40 and RSPs-60 were 2.62% and 1.81%, respectively. The total sugar contents of RSPs-40 and RSPs-60 were 42.5%±0.91% and 45.90%±0.37%, respectively. Protein contents were all 2.89%. The average molecular weights of RSPs-40 and RSPs-60 were 228.298 ku and 124.144 ku, respectively. Monosaccharide composition analysis showed that RSPs-40 mainly consisted of arabinose, galactose, glucose, fructose, and galacturonic acid in a molar ratio of 0.24:0.37:3.22:0.27:1.44, while RSPs-60 was mainly composed of arabinose, galactose, glucose, and galacturonic acid in a molar ratio of 1.58:2.06:2.37:1.69. The results of in vitro antioxidant assays showed that RSPs-40 and RSPs-60 exhibited good DPPH and ABTS free radical scavenging activity. The results of in vitro hypoglycemic assays showed that RSPs-40 and RSPs-60 exhibited stronger α-glucosidase inhibitory activity than acarbose. The antioxidant and α-glucosidase inhibitory activities of RSPs-60 were better than those of RSPs-40. Overall, these results suggested that the polysaccharides from R. sterilis fruit could be explored as a promising antioxidant and hypoglycemic dietary supplement.

Abstract:In order to study the dominant spoilage bacteria of Micropterus salmoides, the 16S rDNA gene sequencing technique was used to isolate and identify the spoilage bacteria. The sensory properties, pH, total volatile base nitrogen (TVBN) value and yield factor (YTVBN/cfu) were used as indicators for systematic evaluation of the spoilage ability of the bacterium strains. The results showed that 9 strains were isolated from the sample of Micropterus salmoides, including Providencia, Hafnia, Aeromonas, Acinetobacter, Enterococcus, Staphylococcus, Shewanella, and Megasphaera. Among them, three were Gram-positive whilst six were Gram-negative. The results of spoilage ability evaluation revealed that it only took 1.5 h for the sample containing Staphylococcus pasteuri from the high quality level to where sensory rejection occurred. After a 24-h culture, the pH value and TVBN value of the sample containing Staphylococcus pasteuri samples could reach the highest (7.35±0.33 and 160.02±0.28 mg/100 g), with a yield factor YTVBN/cfu of 227.32±1.08 (10-9 mg TVBN/cfu) (which was significantly (p<0.05) higher than those for the samples containing other strains. In summary, Staphylococcus pasteuri has strong spoilage and protein decomposition abilities and is the dominant spoilage bacteria of Micropterus salmoides meat.

Abstract:Ethanol was used to extract the active components from the leaves of cizhu, bitter bamboo and four seasons bamboo, and the contents of total flavonoids and total protein were detected at the same time. DPPH free radical scavenging capacity, reducing capacity, inhibiting beta-carotene bleaching capacity and inhibiting lipid peroxidation capacity of the extracts were measured to compare the antioxidant activities of different bamboo leaves. The results showed that the total protein content in ethanol extracts was ordered as follows: bitter bamboo>cizhu>four seasons bamboo, and the total flavonoids content was ordered as follows: cizhu>bitter bamboo>four seasons bamboo. DPPH scavenging ability of bitter bamboo (IC50=1.53 mg/mL) was the strongest, and the reduction ability (IC50=0.55 mg/mL) and inhibiting lipid peroxidation ability (IC50=0.04 mg/mL) of Cizhu were the strongest. DPPH free radical scavenging rate of the three bamboo leaves ranged from 1.53 to 2.71 mg/mL, reducing capacity from 0.55 to 0.97 mg/mL, beta carotene bleaching inhibition from 0.78 to 0.98 mg/mL, and lipid peroxidation inhibition from 0.04 to 0.12 mg/mL. The ethanol extracts of three kinds of bamboo leaves have good antioxidant activities, which can be used in food industry as antioxidants, preservatives or functional food additive.

Abstract:To improve the quality of dehydrated Chinese chives, shorten the drying time and reduce energy consumption, temperature-segmented infrared heating technology was adopted in this research. The drying characteristics, color and rehydration ratio of chives dried by different methods were studied via the combination of high temperature and low temperature using single- and double- plates. The results showed that a large amount of water were removed in the first stage of single-plate drying mode at 80 ℃ for 12 min and 90 ℃ for 6 min, respectively, with the water ratio down to 0.38 and 0.12 respectively. In the second stage, no significant difference in the drying rate for the low-temperature drying at 60 and 70 ℃, with the total drying time ranging in 17~18 min. In the double-plate mode, about half of the moisture was removed quickly in the first stage of drying at 60~90 ℃ for 2~3.5 min, while the second stage of drying was performed at 70 ℃ for 19~23 min or at 60 ℃ for 27~29 min. The combined drying mode eliminated color darkening caused by high-temperature drying. By comparing the color change and rehydration ratio of chives dried by different combinations of processes, one may conclude that the dehydrated chive product treated by single-single temperature variable drying mode had a higher rehydration ratio, while the product treated by double-single temperature variable drying modes had a better color.

Abstract:Rice residue was chose as raw material. The conventional enzymatic hydrolysis was selected as a control. Effects of different ultrasonic power (100 W and 300 W), ultrasonic time (15 min and 30 min) and ultrasonic mode (continuous ultrasonic and working intermittent ratio 2:2 s) on the recovery rate, hydrolysis degree, soluble nitrogen content, surface hydrophobicity and particle size of the enzymatically modified rice residue were investigated. Results showed that different ultrasonic treatment conditions had no significant effect on the recovery rate, soluble nitrogen content and hydrolysis degree of rice residue protein. The protein recovery rate and hydrolysis degree were improved compared with the control group. The surface hydrophobicity increased with the increase of ultrasonic power and ultrasonic time. The surface hydrophobicity of rice residue protein with intermittent ultrasonic treatment was less than that with continuous sonication. When the ultrasonic power increased from 100 W to 300 W, the protein particle size increased from 236 nm to 256 nm, but both were smaller than the non-ultrasound group. Under 15 min ultrasonic treatment, the particle size of the rice residue protein was less than that of the non-ultrasound group, and the particle size increased when time is extended to 30 min. The protein size of rice residue protein with the intermittent ultrasound was larger than that of the continuous ultrasound group, and both were smaller than the non-ultrasound group. Ultrasonic pretreatment can improve the enzymatic sensitization of rice residue protein and increased its hydrolysis degree and protein recovery rate. Compared with the single enzymatic modification, enzymatic hydrolysis combined with ultrasonic pretreament can induce an increase in the soluble nitrogen content of the modified rice residue protein, increasand the decrease in the surface hydrophobicity and the particle size.

Abstract:In order to study the new processing technology of beef pancake, the effects of soybean protein isolate, complex phosphate and carrageenan on shear force, water content and sensory score of beef pancake were studied by single factor experiment. Using shear force, moisture content and sensory score as evaluation indexes, L9(33) orthogonal test was used to optimize the processing technology of beef pancake. The results showed that the range method and principal component analysis method were feasible to evaluate the quality of beef pancakes in different test schemes, but both of them had shortcomings. After comprehensive analysis, the best plan was A1B2C2, that is, the added amount of soybean protein isolate was 2.00%, the added amount of compound phosphate was 0.30%, and the added amount of carrageenan was 0.10%, which was the best processing technology of beef pancake. The moisture content, shear force and sensory score of the beef pancake were 43.61, 7.70 and 84.90 respectively. This study provides a basis for the production of high-grade beef mince products, increasing product types and improving food quality.

Abstract:In order to investigate the effect of storage temperature on the quality of minced beef with different fat content and their water migration, 0%, 10%, 20% butter were added to the minced beef and then packed in trays. The samples were stored at 2 ℃ and -1.5 ℃, respectively. The microbial, physical and chemical properties were detected on the 0, 3rd, 6th, 9th and 12th day of storage. The total number of colonies and the number of psychrophilic bacteria of the 20% tallow group were more than 6.00 log(cfu/g) on the 6th day of storage, which was the highest value among the treatment groups. On the 12th day of storage, the TVB-N value was lower than 25 mg/100 g (the maximum value stipulated by national standards of). Meanwhile, the TVB-N value in the refrigerated group ranged from 25.34 to 25.81 mg/100 g, exceeding the limit of national standards. The addition amount of fat had a significant effect on the value of TBARS. The order of TBARS value was as follow: 20% butter >10% butter >no butter. LF-NMR was used to evaluate water migration. It was found that the content of T22 in ice temperature storage group changed little, while that of T23 increased. The non-flowable water content (P22) decreased and the free water content (P23) increases first and then decreases. Temperature had a significant effect on water migration. The results showed that storage temperature affected the physical properties of minced beef and their water migration. Ice temperature storage can inhibit microbial growth and this technology can improve the physical and chemical stability of the product. Meanwhile, the addition amount of fat had no significant effect on microbial properties and water migration of minced beef. However, it can increase the level of lipid oxidation. As a result, the lightness (L*) and yellowness (b*) increased, while redness (a*) decreased. This study can provide theoretical guidance and scientific basis for the formula of minced beef and their storage.

Abstract:In order to obtain the better drying technology of red jujube chips, jujube slices were dried by heat pump drying (HPD), vacuum freeze drying (FD) and instant controlled pressure drop (DIC) with hot air drying (HAD). The physicochemical and nutritional quality of red jujube slices and dried red jujube chips (RJC) were evaluated and performed a comparative study. Results showed that moisture contents of RJC after four drying methods were all around 4.5%. In terms of texture, HPD, FD and DIC significantly reduced the hardness of RJC and significantly increased the brittleness (p<0.05). As for appearance, compared with HAD, the volume shrinkages of RJC dried by FD and DIC were small, especially for DIC treatment, in which the volume of RJC increased by 3.57%. The least color difference (ΔE) value (1.24) of RJC with brighter surface color was obtained by HPD. However, RJC dried by DIC presented attractive redder surface color even though had a larger ΔE value of 7.19. In terms of nutritional properties, the polysaccharide and flavonoid contents of RJC with four drying treatments all decreased. The highest polysaccharide retention rate was obtained by DIC, which was significantly different from other drying methods. The retention rate of flavonoids in HPD and DIC was significantly higher than that of HAD and FD. In conclusion, DIC can significantly improve the appearance and nutritional quality of RJC, and have a broad industrial application prospects.

Abstract:In order to control the Salmonella contamination on fresh vegetables, in this study, the influences of S. Enteritidis (ATCC13076) adsorption capacity on the lettuce surface under different culture conditions (temperature, pH, ionic concentration) were explored. And then, the effects of chlorine-containing disinfectant and phage on the decrease of S. Enteritidis adhering to the lettuce were compared. The results showed that with the increase of temperature (4~32 ℃) and incubation time (5~60 min), the adsorption of S. Enteritidis on the surface of lettuce increased (3.59~5.20 log cfu/cm2). Then the contaminated lettuce was treated with 10 mg/mL sodium hypochlorite and phage suspension, respectively. The eliminating effect of sodium hypochlorite showed a decreasing trend with increase of incubation time, and the maximum eliminating effect was 3.83 log cfu/cm2 within 2 h, while eliminating effect by phage was increased in different MOI, incubation time and temperature. At 4 ℃and 24 ℃, the highest eliminating effect of S. Enteritidis on lettuce were 1.75 log cfu/cm2 and 1.80 log cfu/cm2, respectively. Therefore, the adsorption of S. Enteritidis on the lettuce were effected by the temperature, time and pH. And compared with sodium hypochlorite, bacteriophage can decrease S. Enteritidis on the lettuce in a safe and effective manner. This study provided a theoretical foundation for further study on the elimination of food-borne bacteria on fresh vegetables.

Abstract:In this paper, the effects of sodium selenite on the growth of marine cultured Chlorella pyrenoidosa and the transformation ability of organic selenium, as well as the main selenium form in the selenoprotein-rich Chlorella were studied. The optimal selenium-enriched culture concentration was determined by adding 2 μg/mL to 50 μg/mL sodium selenite in batches, and the content of three main selenium forms in algae was determined by HPLC: sodium selenite, selenocysteine and selenomethionine. The results showed that the concentration of sodium selenite should not be too high, otherwise the growth of Chlorella pyrenoidosa was inhibited. When the concentration of selenium was 2 μg/mL, the biomass of Chlorella was high, and the content of organic selenium reached 301.40 μg/g, accounting for 83.24% of the total selenium content. HPLC analysis showed that the main forms of organic selenium in Selenium-enriched Chlorella were selenocysteine and selenomethionine under the culture conditions, and the unconverted sodium selenite accounted for only 23.02% of the three major selenium forms determined. The above results indicate that under seawater culture, the suitable selenium concentration for selenium-enriched culture of Chlorella is 2 μg/mL. Under these conditions, the Chlorella pyrenoidosa grows well; the inorganic selenium is effectively converted, and the content of organic selenium is high, which can meet the requirement of selenium enrichment.

Abstract:This present study was based on the feasibility of the saccharified purple sweet potato solution to provide sugar for the fermentation of raspberry wine and the acylated anthocyanins of the purple sweet potato to improve the anthocyanin stability of fruit wine. Using raspberry and purple sweet potato as raw materials, the effects of enzyme type, enzyme amount for addition, and hydrolysis time on the content of reducing sugar and the total sugar of the purple sweet potato solution after liquefaction and saccharification were investigated. The effects of the fermentation method, yeast type, fermentation temperature and raspberry juice amount for addition on the alcohol content, carbon dioxide loss, pH value, content of reducing sugar, total sugar content, total acid content, and anthocyanin content of the compound fruit wine were also examined. The changes in the anthocyanin content of the compound fruit wine, raspberry wine, and purple sweet potato wine were compared. The results showed that the optimum liquefaction and saccharification conditions of purple sweet potato were as follows: fermentation enzyme, high temperature resistantα-amylase; enzyme amount for addition, 0.9 mL/kg; liquefaction time, 3 h; amount of complex saccharifying enzyme for addition, 1.2 mL/kg; saccharification time, 3.5 h. The optimum fermentation parameters for the raspberry-purple sweet potato compound fruit wine were as follows: fermentation method, asynchronous saccharification fermentation; yeast species, BV818 yeast; fermentation temperature, 25 ℃; raspberry juice amount for addition, 60%. The final fruit wine had a alcohol degree of 11.7% vol and good aroma of fruit and wine with soft and refreshing feeling. The use of raspberry-purple sweet potato compound fermentation could improve the stability of anthocyanins in raspberry during wine storage.

Abstract:Quercetin (Que), a highly bioactive component of flavonoids, has extremely high hydrophobicity (which limits its use in the food industry. In this research, wheat protein hydrolysate (WPH) and Que were used to construct composite nanoparticles, and sugar beet pectin (SBP) was added as a natural emulsifier to construct WPH/Que/SBP composite emulsion. The main findings included: WPH could increase the solubility of Que from 8.13 μg/mL to 126.39 μg/mL. During emulsion-based encapsulation, the excellent emulsifying properties of SBP may be beneficial to its dominance in the competition while compensating for the deterioration of emulsifying performance of WPH, causing the decreases in the contents of WPH and Que at the interfaces. With the addition of SBP, the particle size of the composite emulsion decreased significantly, with the average particle size in the surface area of the neutral and the acidic emulsions decreasing from 2.35 μm and 1.03 μm, respectively, to 0.56 μm and 0.76 μm. The composite emulsion exhibited good short-term storage and thermal stability. A pH around the PI value may be beneficial for the complexation of SBP and WPH, thereby, the overall performance of the acidic composite emulsion was better than that of the neutral emulsion.

Abstract:In order to enhance the utilization of quinoa bran, the nutritional components of quinoa bran were determined by the national standard using high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS), and the antioxidant activity of the bran oil was also determined. The results showed that the contents of protein, starch and oil in quinoa bran were 26.86%, 28.78% and 14.15%, respectively. The quinoa bran was also found rich in minerals: Those with higher contents were potassium, magnesium, calcium and iron, and their contents were 9197 mg/kg, 7145 mg/kg, 651 mg/kg, 120 mg/kg, respectively. Six saponins were found, with a total content of 457.61 mg/g. The oil of quinoa bran was composed of 22 fatty acids, among which, the four fatty acids with relative higher levels were elaidic acid, arachidonic acid, erucic acid and oleic acid. The antioxidant activity test revealed that the quinoa bran oil had certain antioxidant activity. At a concentration of 100 μg/mL, the scavenging rates of DPPH free radical and superoxide anion were 9.26% and 4.06% respectively. The quinoa bran was rich in all kinds of nutrients and active substances, and had some potential for development and utilization.

Abstract:In this paper, an antioxidant composite was prepared using chitosan as the main material. Chitosan was modified by natural aromatic amine compound via grafting reaction and then blended with nanocellulose with higher aspect ratio, forming a new composite material. The structure of the polymer was characterized by FT-IR, 13C NMR and elemental analysis, which proved the success of adenine grafting. The antioxidant test results show that the obtained composite showed much higher strength than both chitosan and cellulose. Antioxidant evaluation also showed that the antioxidant activity of chitosan-based material significantly improved DPPH scavenging capability. The DPPH radical scavenging activity of MCBC membrane can reach 72.20%. And the doping of nanocellulose further increased its mechanical properties and dimensional stability. The tensile strength of MCBC-CNF-2 membrane reached 65.06 MPa, and the water absorption and swelling ratio were only 36.20% and 6.06%, respectively. Although the antioxidant activity of the modified chitosan membrane decreased with the increase of nanocellulose doping amount, the DPPH radical scavenging activity of MCBC-CNF-2 membrane still reached 54.20%. This obtained composite material was biodegradable and cost-effective, which is expected to be applied to food packaging materials.

Abstract:Staphylococcus xylosus (SX) and Lactobacillus plantarum (LP) were used as research objects to investigate the effects of different starter cultures (SX; SX+LP) on ham flavor. The cryoprotectant formula of SX (8.05% skim milk, 8.83% sucrose, 7.78% sorbitol) and LP (6.43% for skim milk, 7.91% for sucrose, 4.28% for sorbitol) were optimized by single-factor and response surface tests. Direct vat starter of SX and LP was prepared for ham fermentation. SX and SX+LP were inoculated into fermented ham to study the effect of different starter cultures on the flavor quality of fermented ham. The HS-SPEM-GC-MS technique was used to detect the type and content of volatile flavor compounds in SX+LP, SX and control sample, 53, 52 and 31 volatile flavor substances were detected, respectively. In samples with starter culture, the content of aldehydes with lower odor thresholds increased, while the content of hydrocarbons with higher odor thresholds decreased. The amount of the main flavor substance in the SX+LP sample was the most, followed by the SX and the control sample. At the same time, the PCA biplot showed that SX+LP sample can be discriminated by 11 main flavor substances on PC1, SX sample can be distinguished on PC2 by four main flavor substances, and only one characteristic flavor substance can be used to identify control sample. This result indicated that both SX and LP can improve the flavor quality of fermented ham, and the mixture culture starter is better than the single culture starter.

Abstract:In this wok, the extraction method of total flavonoids from old leaves of Toona sinensis was studied. Firstly, cellulose and pectin in the old leaves of Toona sinensis were hydrolyzed by complex enzymes, and the optimal enzymatic hydrolysis condition was found to be complex enzyme 2 (pectinase: cellulase=2:1), with an enzyme dosage of 2.00% (W/V), enzymatic hydrolysis time of 40 min, enzymatic hydrolysis temperature of 45 ℃, and the total flavonoids yield in the supernatant was 2.49%. Ultrasonic assisted extraction was performed later. The single factor experiment and the Box Behnken were used to optimize the ethanol volume ratio, ultrasonic power, ultrasonic time, ultrasonic temperature. The variance analysis showed that the yield of total flavonoids from old leaves of Toona sinensis was affected by following: the ultrasonic power > ethanol concentration > extraction temperature > extracting time. According to the regression equation, the best extraction conditions were predicted. Under the conditions of ethanol volume fraction of 60%, ultrasonic power of 227 W, extraction temperature of 53.00 ℃ and extraction time of 51 min, the total flavonoids yield of old leaves of Toona sinensis was 3.85%, which was only 0.03% different from the predicted value, indicating that the process parameters were accurate and reliable.

Abstract:In order to evaluate the nutritional level of the gonads of the female Argentine squid, the general nutrition including amino acid, fatty acid and inorganic elements were analyzed. The results showed that the content of water, crude protein, crude fat and crude polysaccharide (measured by dry weight) were 64.94%~73.39%, 54.61%~73.40%, 2.88%~3.13% and 1.33%~2.79% respectively. In the glands of female Argentine squid 15 kinds of amino acids were detected, of which in the total content was 266.33~369.01 mg/g. The content of essential amino acids was 99.41~159.69 mg/g and accounted for 37.33%~43.78%. The ratio of essential amino acids to nonessential amino acids was 59.56%~77.87%. The composition of essential amino acids is accord with FAO/WHO ideal mode, so that it is a source of high-quality protein. A total of 7 fatty acids were detected, in which the unsaturated fatty acids accounted for 83.77%~85.83%. In the gonads K+, Ca2+, Na+ and Mg2+ were also found in abundant. The experiments results suggested that the gonads of female Argentine squid were rich in nutrition with high value of development and utilization.

Abstract:The nutritional components of Chrysanthemum was evaluated to provide a theoretical experimenta basis for the rational development and utilization of Chrysanthemum. The results showed that the contents of crude protein, moisture, crude ash, crude fibre, crude fat, total flavonoids, soluble sugar and crude polysaccharides in Chrysanthemum were 12.9%, 11.5%, 5.6%, 5.2%, 4.9%, 3.97%, 19.5% and 5.91% respectively. The polysaccharide content was significantly higher than that in other varieties of Chrysanthemum (0.1%~4.0%). The Chrysanthemum had 17 kinds of amino acids and a total amino acids content of 10.69%, among which cystine was rarely detected in other varieties of Chrysanthemum. Among the 11 kinds of vitamins detected in the Chrysanthemum (VA, VB1, VB2, VB6, Vc, VD2, VD2, VE, β-carotene, niacin and nicotinamide), VA, β-carotene (provitamin A), VE, VB2, nicotinamide and Vc had a content of 0.22, 0.28, 26.71, 0.11, 72.3 and 14.7 mg/100 g, respectively. The Chrysanthemum was rich in niacinamide and VE, with the VE content equivalent to that of nuts. The Chrysanthemum was also abundant in minerals, with 13 kinds of mineral elements (K, Na, Ca, Cu, Fe, Mg, Mn, P, Zn, Se, Pb, As and Cd) being detected except for Se. The content of Ca was 2994 mg/kg, which was higher than that of milk (1040 mg/kg). The content of Fe was 101.6 mg/kg, which was higher than those of pig blood (87 mg/kg) and yolk (65 mg/kg). The contents of heavy metals (Pb, As and Cd) all met the tolerance limit of the national standards. In conclusion, Chrysanthemum had high nutritional and medicinal values and great development potential, thus, can be used for the development of chrysanthemum foods and health products.

Abstract:The citrus pu-erh tea dried by sunlight was prepared from raw pu-erh tea and mandarin peel. A total of 60, 97, 116, 78 and 75 aromatic components were identified from raw pu-erh tea, mandarin peel, citrus pu-erh tea, the interior of citrus pu-erh tea and the surface of citrus pu-erh tea by the simultaneous distillation extraction and GC-MS, which were accounted for 96.39%, 97.07%, 91.47%, 93.13%, and 97.53% of the total volatile substances, respectively. According to the analysis results, some new specific aroma components were formed during the citrus pu-erh tea processing, while the main aromatic components of raw pu-erh tea and mandarin peel, such as limonene, methyl 2-(methylamino)benzoate, g-terpinene, linalool, (+)-alpha-pinene and myrcene were remained. Among the key aroma components, one part was the compounds with a significantly higher relative content than raw pu-erh tea and mandarin peel, such as 4-terpinol, (-)-trans-Carveol, Cumene, (+) – carvone and 3-methyl-4-(1-methylethyl)-pheno, and another part was the compounds generated substances during process, such as 4-carvomenthenol, pinocarvone, piperitone, carvenone, p-acetanisole, geranyl isovalerate, isodurene, r-muurolene and N-ethylpyrrole. Therefore, the above aromatic components together formed the unique aromatic quality of citrus pu-erh tea, and were also responsible for the potential pharmacological activity.

Abstract:To improve the discrimination ability of MALDI-TOF MS in identifying Listeria species, the objective of this work was to establish a rapid and accurate MS method to discriminate L. monocytogenes and L. innocua. Protein mass spectra of 79 verified L. monocytogenes and 57 L. innocua strains were generated using MALDI-TOF MS and subsequently analyzed with ClinPro tools software for specific biomarker identification and discrimination model establishment. The results of peak statistic showed that 16 specific peaks with significant difference were identified, including 6 L. monocytogenes and 10 L. innocua specific biomarker candidates, respectively. It was found that the mass peaks 3985/7970 u and 3972/7942 u in Listeria monocytogenes were independent and linked. Furthermore, the discrimination model based on genetic algorithm presented better cross validation (99.44%) and recognition capability (100.00%), and correct classified rate could reach above 96%, which can obtain the rapid and accurate identification for L. monocytogenes and L. innocua. Meanwhile, main spectra of a defined collection of these strains were compiled using Bruker Biotyper software and added to an in-house reference library. Evaluation of this library with 8 untested Listeria strains yielded improved score values, which were higher than that of commercial database. Application of the in-house database can improve the automatic identification capability of MALDI-TOF MS for Listeria species.

Abstract:In order to analyze the spoilage bacteria which caused the spoilage of the vacuum-packed RTE abalone, the solid phase micro-extraction coupled with gas chromatography-mass spectrometry (GC-MS) were used to analyze the changes of volatile components before and after the spoilage of RTE abalone, and the contaminated abalone by Clostridium sporogenes which was the spoilage bacteria of RTE abalone. The results showed that RTE abalone produced obvious scent of roast meat. Alcohols (51.93%), nitrogen-containing sulfur (20.91%) and aldehyde (6.62%) compounds were the main sources of volatile components. And butanediol (42.64%). methylpyrazine (12.41%) were the most important characteristic flavor substances of RTE abalone. But the naturally spoiled abalone produced significant fecal odor and rancidity. It mainly contained nitrogen-containing sulfur (49.16%), aromatic (20.73%), and acid (18.83%) compounds. Indol (41.93%), aromatic (20.73%), 2-methylbutyric acid (7.13%), which were the characteristic flavor substances of the natural spoilage abalone. The contaminated abalone by Clostridium Sporogenes also produced significant fecal odor and rancidity. The most important volatile substances in contaminated abalone were acid (45.76%) and nitrogen-containing sulfur (18.25%) compounds. The 4-methylpentanoic acid (37.49%), dimethyl trisulfide (8.16%) and indol (5.76%) were characteristic flavor substances of contaminated abalone. Clostridium is one of the most important microbial contamination sources for vacuum-packed food, and it is necessary to adopt a more efficient and safer sterilization method to kill Clostridium.

Abstract:In order to detect excessive talc powder illegally added in flour, a near infrared multi-spectral quantitative detection method was proposed. Firstly, the samples with 0%, 0.5%, 1%, 3%, 5%, 10%, 15% and 20% talc powder mass fraction were prepared. The original spectra of the samples within the wavelength range of 900~1700 nm was acquired. With the increase of talc powder mass fraction, the amplitude of the sample spectrum curve decreased gradually in the range of 1160~1700 nm, and small absorption peaks appeared at 1393 nm in the spectrum curve of the samples with sufficient doping talc powder as compared with that of pure talc powder. By comparing the prediction results of the full-wavelength model corresponding to seven different pretreatment methods, the standard normal variables were selected as the optimal pretreatment method. Furthermore, three variable optimization methods were used to extract the optimal wavelengths and then the corresponding multispectral quantitative detection models for talc content in flour were established. The results showed that the competitive adaptive re-weighted sampling (CARS) method had the best detection effect among the three multispectral models. The verification set R2p was 0.998 and RMSEP was 0.282%. The continuous projection algorithm (SPA) method had the least number of wavelengths and the smallest collinearity among them. The detection limits of the three multi-spectral models corresponding to the three wavelength selection methods can all reach 0.5%, which can provide a theoretical basis for the development of portable or on-line testing instruments.

Abstract:In this paper, the volatile components were analyzed using sensory evaluation, simultaneous distillation-extraction (SDE) coupled with gas chromatography-mass spectrometry (GC-MS) and GC-olfactometry (GC-O) in the instant Dianhong tea. Sensory evaluation showed that floral was the main flavor profile of the instant Dianhong tea, and there is also a certain sweetness and grass aroma. In addition, 27 volatiles, including 2 aldehydes, 11 alcohols, 4 ketones, 4 esters and 6 others were identified using GC-MS. The quantitative analysis showed that the main volatile substances were benzyl alcohol (3.38 μg/g), linalool (3.52 μg/g), menthol (18.00 μg/g), 4-oxoisophorone (3.53 μg/g), dihydroactinidiolide (80.26 μg/g), hexadecanoic acid (20.60 μg/g) and 4-vinyl-guaiacol (20.60 μg/g), respectively. The GC-O and OVA analysis indicated that phenylacetaldehyde, phenylcarbinol, linalool oxide I, linalool geraniol and indole were the main aroma-active substances. The experiment provided theoretical basis for the flavor study of the instant black tea and other instant tea.

Abstract:A fast and easy method for the quantification of 8 basic dyes in food (bread, orange juice and stewed bean curd) was investigated by ultra performance liquid chromatography-quadrupole/electrostatic field obitrap high-resolution mass spectrometry. The sample was extracted by ethyl acetate, C18 (3.0 mm×100 mm, 1.8 μm) was used as chromatography column to separate the basic dyes with a gradient elution of acetonitrile and 10mmol/L ammonium acetate aqueous solution as the mobile phase. The 8 basic dyes were analyzed in positive and negative mode. The retention time, accurate mass of parent ion and relative isotope abundance were used for fast screening in full scan mode, while accurate mass of fragment ions was used for confirmation in two-stage threshold-triggered full mass scan mode. Under the optimal conditions, good linearities (R2>0.99) were obtained in their respective linear ranges. The recoveries were in the range of 82.2%~105.3% and the relative standard deviation was 6.0%~9.9%. The method was simple, sensitive, accurate and suitable for the rapid screening and confirmation of 8 basic dyes in food.

Abstract:In order to effectively detect the grain hardness in high humidity environment, the hyperspectral image of wild two-grain wheat produced by a cereal processing factory was obtained by hyperspectral image system. The adaptive denoising method (PLS) based on matching idea was used to remove the banded noise of hyperspectral image of wild two-grain wheat and enhance the quality of hyperspectral image of wild two-grain wheat in high humidity environment. On this basis, the average value of spectral data of wild two-grain wheat was taken as spectral data, and the prediction model of grain hardness of wild two-grain wheat in high humidity environment was constructed to realize the accurate detection of grain hardness in high humidity environment. The simulation results showed that when the humidity of processing environment was 55%, the average value of grain hardness of wild two-grain wheat detected by the proposed method was 1745 g, and the difference between the proposed method and the standard infrared detection method was only 3 g. When the ambient humidity was increased to 75%, the result of the proposed method was 1712 g, which is 42 g different from the standard infrared detection method. The proposed method had a high precision in detecting grain hardness of wild two-grain wheat, which is better than the acoustic vibration frequency band amplitude characteristic method.

Abstract:Rice and wheat are staple grain crops in China, however, they are susceptible to the enrichment of heavy metal elements during their growth. The heavy metal elements in rice and wheat enter the human body via the supply chain, and an excessive intake of heavy metal elements does great harms to the human health. In China, the soils or irrigation water sources in some crop growing areas are contaminated by industrial wastes, causing the contents of heavy metals in the crops to exceed the relevant standards (which poses a great threat to food safety). Current studies have shown that the contents of heavy metals in rice and wheat are greatly influenced by the processes and methods. Husking, milling and other processes can reduce the contents of heavy metals in rice to different extents; wheat flour milling can also reduce the contents of heavy metals in wheat flour. However, processing machinery may also cause secondary heavy metal contamination of products. The clarification of the influence of processing on the contents of heavy metals in rice and wheat is important for designing and controlling the processing steps of rice and wheat. This paper introduces briefly the chemical valence of the heavy metals in rice and wheat and their distribution in different in parts of the grain structures, and reviews mainly the influence of typical processing steps on the contents of heavy metals in rice and wheat. A summary of the research status is also provided, with the aim of providing a reference for preventing and controlling heavy metal contamination during rice and wheat processing.

Abstract:Morinda citrifolia (Morinda sp, Rubiaceae), also known as NONI, has a 2000-year history of use as an edible and medicinal plant in Polynesia. There are abundant endophytes in the fruit of Morinda citrifolia. Natural fermentation is an important process for its processing. Therefore, it is of great significance to study the endophytic bacteria and active components in these fruits. This paper reviews the type of endophytic microorganisms as well as the structure of the main active components-phenolics, including terpenoids, coumarins, lignans, flavonoids, phenolic acids and other phenolics in the fruit of Morinda citrifolia. Physiological activities of the Morinda citrifolia fruit were summarized (mainly including bacteriostasis, protection against liver damage, anti-cancer activity, anti-oxidative effect, cardiovascular protection and immunity enhancement), to provide a theoretical basis for the studies of functional foods and medicines, which is conducive to the wider and effective use of Morinda citrifolia fruit. This review also aimed to provide the reference for further research on the natural fermentation process of foods