Objective: A process was developed for the purification of bran polyphenols from HPD 600 macroporous resin. The purity and antioxidant activity of the extracts were analyzed before and after purification, and the polyphenol fractions in the purified products were characterized. Methods: The bound polyphenols in wheat bran were extracted by alkali hydrolysis, and the dynamic adsorption-desorption conditions of the macroporous resin were optimized by single-factor test to determine the optimal purification process. The antioxidant activity fraction was determined by ABTS and DPPH radical scavenging rate. The characterization of the polyphenol fraction in the purified product was completed by UPLC-MS/MS. Results: Under optimal process conditions, the purity of the polyphenols and the antioxidant activity of the purified product were significantly increased. The purified products contained mainly nine polyphenolic compounds, in order of retention time: p-hydroxybenzoic acid, caffeic acid, vanillin, p-coumaric acid, trans-ferulic acid and salicylic acid. Conclusion: The macroporous resin purification process is effective in enriching bran polyphenols and the resulting purified product has a significantly higher antioxidant capacity, while maintaining the richness of the polyphenolic species.

Objective: Using wheat bran as raw material, the extruded bran is obtained by extrusion stabilization treatment, and the best drying method for extruded bran is determined. Methods: The effects of three drying methods （fluidized bed drying, microwave drying, hot air drying） were studied on the basic components of extruded bran, water holding capacity, water solubility, swelling power, oil holding power, color value and other physical and chemical properties, oxidation resistance, total phenols and total flavonoids; Using antioxidant, total phenols and total flavonoids as indicators to determine the best drying method for extruded bran. Results: The three drying methods have no significant effect on the crude protein, crude fat, ash and TDF of the extruded bran; Compared with fluidized bed drying, microwave drying and hot air drying can increase the content of starch and crude fiber; Drying has an effect on extrusion, and the influence of the water solubility of extruded wheat bran is: hot-air drying ＞ fluidized bed drying ＞ microwave drying; Compared with microwave drying and hot-air drying, fluidized bed drying can improve the expansion force and oil holding capacity of extruded bran; Compared with fluidized bed drying and hot-air drying, microwave drying can improve the water holding capacity, oxidation resistance, total phenol and total flavonoids content of extruded bran, and reduce brightness and whiteness. Conclusion: The best drying method is determined to be microwave drying.

以小麦粉和可食用麸皮为原料,探究经挤压处理后不同麸皮粒度对小麦粉糊化特性和热机械学特性的影响.结果表明:中、小粒度麸皮对小麦粉色差、峰值黏度、最低黏度、最终黏度的影响显著大于大粒度麸皮(P＜0.05),这是因为中、小粒度麸皮与面粉混合得更均匀,减少了反光量、导致色差增大,并通过阻碍面筋网络结构的形成来影响糊化特性;吸水率随麸皮粒度的减小而增大,这也使得面团形成时间和稳定时间显著降低(P＜0.05);中、小粒度麸皮还会显著降低淀粉的回生值,有利于延长面制品的货架期.

文章先通过单因素试验考察了挤压温度、液体进料量、固体进料量以及螺杆转速对小麦麸皮抗氧化能力、可溶性酚酸及黄酮含量的影响.在单因素试验的基础上,设计3因素3水平正交试验,研究挤压工艺对小麦麸皮抗氧化活性和可溶性酚酸含量的影响,探讨最佳的挤压工艺参数.结果表明:挤压加工可以改变小麦麸皮的抗氧化能力、可溶性酚酸含量和黄酮含量.小麦麸皮最佳的挤压参数:挤压温度90℃,液体进料量22％,螺杆转速160 r/min,固体进料量10kg/h.此条件下挤压后,小麦麸皮总抗氧化活性为(13.888±0.15)μmol/g,可溶性酚酸含量为(3.1955±0.10)mg GAE/g.

小麦麸皮由各种组织细胞层组成,依次为果皮层、皮层、透明层和糊粉层.研究表明麸皮食品具有潜在的健康益处.因此,综述小麦麸皮的成分及营养特性,同时对小麦麸皮在食品中的应用研究进展进行介绍.

通过溶液共混法制备了ε-聚赖氨酸的浓度分别为0％、5％和10％的壳聚糖/ε-聚赖氨酸涂液及复合膜,对其抑菌性进行了表征,并将壳聚糖/ε-聚赖氨酸涂液应用于龙眼,考察其对龙眼的保鲜性能影响.结果发现,壳聚糖/ε-聚赖氨酸膜具有优异的抑菌性,其抑菌性随着ε-聚赖氨酸含量的增加而增强.随着ε-聚赖氨酸含量的增加,壳聚糖/ε-聚赖氨酸涂液能更好地抑制龙眼失重率和果皮褐变率的上升,延缓可溶性固形物的减少,从而提高了龙眼的好果率.在本实验中,ε-聚赖氨酸浓度为10％的壳聚糖/ε-聚赖氨酸涂液对龙眼的保鲜效果最好.