不同预处理对提高大果沙棘热风干燥效果的对比分析

Comparative Analysis of Different Pretreatment on Improving Hot Air Drying Effect of Seabuckthorn (Hippophae rhamnoides L.)

摘要:

通过研究不同预处理对大果沙棘热风干燥微观结构、干燥特性及品质的影响，以期为筛选适宜大果沙棘热风干燥的预处理方式提供理论依据和技术参数。以新鲜大果沙棘为原料，采用不同预处理（蒸馏水（对照）、70 ℃烫漂、150 W超声、2% Na2CO3、2%促干剂和2% NaHCO3）对大果沙棘预处理后进行热风干燥，分析不同预处理对大果沙棘干燥前表皮微观结构、干燥过程中的干燥特性及干燥后品质指标的影响。结果表明，不同预处理对大果沙棘果实表皮微观结构均有不同程度的影响，2% Na2CO3预处理对其蜡质溶解和气孔结构破坏最为明显；70 ℃烫漂、2% Na2CO3、2%促干剂和2% NaHCO3预处理均可显著缩短大果沙棘热风干燥时间，其中2% Na2CO3预处理效果最显著，仅需44 h，与对照（118 h）相比，缩短了62.71%；经2% Na2CO3预处理后，大果沙棘热风干燥品质较优，其中Vc含量为351.90 mg/100 g DW、总黄酮含量为12.86 mg RE/g DW、总酚含量为7.50 mg GAE/g DW，且色泽最接近于新鲜果实。可见，2% Na2CO3浸泡1 min为热风干燥较佳的预处理方式，可在生产中进行应用和推广。

Abstract:

The effects of different pretreatments on the microstructure, drying characteristics and quality of hot air drying of Hippophae rhamnoides L. were studied, which provided theoretical basis and technical parameters for screening suitable pretreatment methods of hot air drying of Hippophae rhamnoides L. Fresh Hippophae rhamnoides L. was used as raw material. Different pretreatments (distilled water (control), blanching at 70 ℃, 150 W ultrasound, 2% Na2CO3, 2% grape drier and 2% NaHCO3) were used to dry the pretreated Hippophae rhamnoides L. with hot air. The effects of different pretreatments on the microstructure of epidermis before drying, drying characteristics during drying and quality indexes after drying were analyzed.The results showed that different pretreatments had different effects on the epidermis microstructure of Hippophae rhamnoides L. fruits, and 2% Na2CO3 pretreatment had the most obvious effect on wax dissolution and stomatal structure destruction. Blanching at 70 ℃, pretreatment with 2% Na2CO3, 2% grape drier and 2% NaHCO3 can significantly shorten the hot air drying time of Hippophae rhamnoides L. Among them, pretreatment with 2% Na2CO3 is the most effective, requiring only 44 hours, which is 62.71% shorter than that of the control (118 hours).After pretreatment with 2% Na2CO3, the hot air drying quality of Hippophae rhamnoides L. was better, with the Vc content of 351.90 mg/100 g DW, the total flavonoids content of 12.86 mg RE/g DW, and the total phenol content of 7.50 mg GAE/g DW, and the color and luster were the closest to those of fresh fruits. It can be seen that soaking 2% Na2CO3 for 1 min is a better pretreatment method for hot air drying, which can be applied and popularized in production.