苹果浓缩汁美拉德反应有关影响因素的研究

以苹果制汁新品种鲁加1号和鲁加3号特拉蒙（Telemon）×富士（Fuji）]的浓缩果汁为试材，研究了苹果浓缩汁贮藏过程中氨基酸、还原糖和5．羟甲基糠醛（5-HMF）含量的变化，并利用几种氨基酸和还原糖分别在柠檬酸-磷酸缓冲液（pH3．20）与苹果浓缩汁中进行美拉德模拟试验。实验结果表明：贮藏过程中，苹果浓缩汁中的赖氨酸、苯丙氨酸、亮氨酸、异亮氨酸、蛋氨酸、苏氨酸的含量呈下降趋势；还原糖含量成波浪式变化，即先上升后下降，然后上升再下降；5-HMF含量先上升后下降；在柠檬酸．磷酸缓冲液中进行美拉德模拟试验其氨基酸与还原糖的反应活性分别与苹果浓缩汁中的反应活性存在较大差异，在两个实验中赖氨酸都具有较大的反应活性。

Study on Factors Influencing Maillard Reaction in Apple Juice Concentrate

Studies were carried out on changes of amino acids,reduce sugar and 5-HMF contents in apple juice concentrate of Lujial and Lujia3(Lu for Shandong province,China;Jia for processing)derived from the cross between Telamon and Fuji. Maillard reaction had been simulated with amino acids(lysine,phenylalanine,leucine,isoleucine,methionine,threonine)and reduce sugars(fructose,glucose,arabinose,galactose,xylose)respectively in citric acid-phosphate buffer(pH3.20)and in apple juice concentrate.The results showed that lysine,phenylaianine,leucine,isoleucine,methionine and threonine contents in apple juice concentrate decline during storage.Reduced sugar content increases first,then decreases,while roses and descends again.5-HMF content increases first,then descreases.Amino acids activities in Maillard reaction show great differences between in citric acid-phosphate buffer(pH3.20)and in apple juice concentrate,and also in reduce sugars activities. Lysine activity is high in both experiments.