反应时间对大豆肽-木糖美拉德反应体系的影响

Effect of Reaction Time on Soybean Peptide-Xylose Maillard Reaction Systems

为了考察反应时间对大豆肽在美拉德反应中的变化规律,本研究以不同分子量分布大豆肽-木糖(SP1/SP2/SP3/SP4/SP5-xyl)为反应体系,研究不同反应时间(0-180min)对pH、A420、游离氨基酸和不同分子量分布肽含量的影响。结果表明,随着反应时间的延长,各体系的pH逐渐降低,褐变强度逐渐增强,其中SP1-Xyl体系中两指标变化程度最大,而SP5-Xyl体系变化程度最小。同时发现,各反应体系中游离氨基酸含量先降低而后稳步增加。随着反应时间的延长,SP1-Xyl和SP2-Xyl体系中美拉德肽含量逐渐增加,相对分子质量小于1000的产物含量逐渐减少,大于5000的产物含量逐渐增加;SP3-Xyl体系中美拉德肽含量变化不显著;SP4-Xyl和SP5-Xyl体系中美拉德肽含量逐渐降低,相对分子质量大于5000的产物含量逐渐增加,小于1000的产物含量仅在后者体系中显著增加。感官评定结果显示,反应时间控制在120-150min,所获得的MRPs提升鲜味、醇厚味和持续感的呈味效果较好。

The five soybean peptides （SPs） characteristic were researched during heating with xylose （Xyl） as a function of time （0-180min）, by the investigations of pH, A420, the content of free amino acids and peptides with the different molecular weight distribution. The results showed that pH value decreased and browning intensity became strong as the heating time increased in five systems. The changes in pH and browning intensity were the highest in SP1-Xyl system, the lowest in SP5-Xyl system. Additionally, the free amino acids contents of all sys-tems decreased and then gradually increased with the prolonged heating time. In SP1/SP2-Xyl systems , increase time favored the formation of Maillard peptides and the MRPs above 5000 Da , while causing the decrease of the MRPs below 1000 Da; in SP3-Xyl system, the content of Maillard peptides was not greatly affected by heating time; in SP4/SP5-Xyl systems, prolongiong time was unfavorable for the effective conversion of Maillard peptides as well as to the accumulation of MRPs above 5000 Da, however, the MRPs below 1000 Da only increased in the latter system. Sensory evaluation revealed that MRPs prepared in a range of time 120-150min , exhibited strong fla-vor-enhanced characteristics including umami, moulthfullness and community and was proper for preparation of fla-vorings with enhanced-flavor properties.