加热后低温放置对美拉德反应特征颜色和抗氧化性的影响

Effect of two phases of high and low temperatures on characteristic color development and antioxidant activity in Maillard reaction system

为分析短时加热与低温相结合对美拉德反应颜色特征、抗氧化性和反应进程的影响,利用木糖与甘氨酸模式美拉德反应体系,在60℃预加热0、0.5、1h后,置于4℃条件下观测反应变化。通过吸光值和色差的测定、紫外可见吸收光谱的分析、ABTS及DPPH自由基清除率的变化反应体系特征颜色和抗氧化性的变化。结果表明,60℃加热时间越长,木糖-甘氨酸美拉德反应体系的初始吸光值、b值和自由基清除率越大且变化幅度较快,而初始L值和a值则越小。在4℃下放置,反应体系的吸光值均随着反应时间的延长呈现上升趋势;L、a、b值均呈现下降趋势;加热0和0.5h的反应体系在紫外区265nm处出现特征峰,而加热1h的体系无此特征峰出现,不同体系在可见光区均在580nm和630nm处出现特征峰,且随着反应时间的增加吸光强度不断增大;ABTS、DPPH自由基清除率均随着反应时间的延长呈现上升趋势,但ABTS自由基清除率的增加较明显,而DPPH自由基清除能力增加较平缓。

Characteristic color development and free radical scavenging activity in XyI-Gly Maillard reaction system was investigated under two phases of high and low temperatures.The XyI-Gly Maillard reaction system was heated at 60~C for 0,0.5, ] h and then set at 4~（3 for 15d.The results showed that,the longer time heated at 60~C,the greater initial values of absorbance, b and free radical scavenging rates.The absorbance intensity gradually increased, and the color values of L, a, b all decreased during t5d at 4~C. The characteristic peaks at 265,580 and 630nm appeared on the UV-Vis,with increased absorbance intensity at 580 and 630rim and disappearance of the peaks at 265nm. ABTS and DPPH radical scavenging rates increased with increasing time at 4~C. Preheating could promote the Maillard reaction in low temperature, but the characteristic peak at 265nm disappeared as heating temperature increased.