毛酸浆发酵过程中非酶褐变影响因素研究

为解析毛酸浆果汁在发酵过程中非酶褐变的机理,研究在同时接入酵母菌和乳酸菌,于25℃和37℃的发酵过程中各影响因素对非酶褐变的影响。以色差(△E)值为指标,检测其在发酵过程中引起非酶褐变的抗坏血酸(Vc)、5-羟甲基糠醛(5-HMF)、多酚、还原糖、氨基态氮等主要致褐因素的变化。通过通径系数分析方法,分析毛酸浆发酵过程中非酶褐变的主要影响因素。结果表明,在25℃发酵条件下,5-HMF对色差△E值起到的直接作用最强,5-HMF和氨基态氮的交互作用是决定色差△E值的第一决定因素;在37℃发酵条件下,5-HMF对色差△E值起到的直接作用最强,5-HMF和还原糖的交互作用是决定色差△E值的第一决定因素。说明毛酸浆发酵液中5-HMF、还原糖和氨基态氮是导致毛酸浆发酵过程中非酶褐变的最重要因素。

Factors Affecting Non-enzymatic Browning of Fermented Physalis pubescens L.Juice

Key elements involving in the non-enzymatic browning of fruit juice of Physalis pubescens L.during fermentation were analyzed to understand the underlying mechanism.A symbiotic fermentation on the juice using yeast and lactic acid bacteria simultaneously at 25℃ or 37℃ was conducted.Color changes,△E,along with the contents of vitamin C,total phenols,5-hydroxymethylfurfural (5-HMF),reducing sugar,and amino acid nitrogen of the juice during the entire process at various temperatures were monitored for a path coefficient analysis.The results indicated that 5-HMF had the strongest effect on △E,and that its interaction with the amino acids was the main cause of the non-enzymatic browning at 25℃.At 37℃,the interaction between 5-HMF and reducing sugars appeared to be the prime source for the browning of the juice.It was,thus,concluded that 5-HMF,reducing sugars and amino acids were among the key elements that led to the color change of the fruit juice during fermentation.