乳酸菌发酵香菇汁过程中品质变化及动力学模型的建立

Quality Change and Kinetic Model of Lentinula edodes Juice Fermentation by Lactic Acid Bacteria

摘要:

利用乳酸菌发酵香菇汁，研究发酵过程中活菌数、理化指标及抗氧化活性的变化规律，并采用Logistic、SGompertz、Boltzmann和DoseResp模型对发酵过程中乳酸菌生长、总酸生成及还原糖消耗进行非线性拟合，建立乳酸菌发酵香菇汁的发酵动力学模型。结果表明，乳酸菌在香菇汁中生长良好，24 h时活菌数最高，为8.95 log CFU/mL；发酵过程中总酸、总酚、总黄酮、可溶性蛋白含量不断升高，最高分别达到6.86 g/L、232.82 mg/L、101.89 mg/L、291.25 μg/mL；DPPH自由基、羟自由基和超氧阴离子自由基清除能力较发酵前分别提升了54.46%、26.96%和211.84%。在乳酸菌生长和总酸生成的动力学模型中，均采用Dose Resp模型最佳，R2分别为0.998 7和0.999 8；Boltzmann模型和Dose Resp模型均可用于定量描述发酵过程中还原糖的消耗情况，两个模型的R2均为0.999 6。因此，利用乳酸菌发酵可提升香菇汁品质，所选模型与实验值拟合度较高，能够较好反映乳酸菌发酵香菇汁过程中的动力学特征，为乳酸菌发酵香菇汁的进一步工业化生产提供理论依据。

Abstract:

Lactic acid bacteria was used for Lentinula edodes juice fermentation. The changing trends of viable bacterial counts, physicochemical indexes, and antioxidant activities during the fermentation process were investigated. The growth of lactic acid bacteria, total acid production, and reducing sugar consumption were fitted using the Logistic, SGompertz, Boltzmann, and Dose Resp models to establish the kinetic model for Lentinula edodes juice fermentation by lactic acid bacteria. The results show that lactic acid bacteria grew well in Lentinula edodes juice, with the highest viable count (8.95 log CFU/mL) occurring at the 24th h. The total acid content, total phenolic content, total flavonoid content, and soluble protein content increased continuously during the fermentation process, reaching maximal values of 6.86 g/L, 232.82 mg/L, 101.89 mg/L, and 291.25 μg/mL, respectively. The scavenging capacity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, and superoxide anion radical increased by 54.46%, 26.96%, and 211.84%, respectively, compared with those before fermentation. The Dose Resp model was the best kinetic model for both the lactic acid bacteria growth and total acid production, with R2 values being 0.998 7 and 0.999 8, respectively. Both the Boltzmann model and the Dose Resp model can be used to describe quantitatively the consumption of reducing sugars during the fermentation process, with R2 values being 0.999 6 for both models. Therefore, the quality of Lentinula edodes juice can be improved via fermentation with lactic acid bacteria. The selected models fit well with the experimental values, which can reflect the kinetic characteristics of Lentinula edodes juice fermentation by lactic acid bacteria. This study provides a theoretical basis for further industrial production of fermented Lentinula edodes juice with lactic acid bacteria.