高温灭菌过程中三种鲜食玉米汁游离糖与氨基酸含量变化的比较

Change of Free Sugars and Amino Acids in Fresh Corn Juice during Autoclaving

摘要:

为明确鲜食玉米汁在高温灭菌过程中滋味成分的变化特点，采用HPLC对甜玉米、糯玉米和常规玉米汁在灭菌过程中蔗糖、果糖、葡萄糖和19种游离氨基酸的含量变化进行了测定和分析。结果显示，甜玉米汁中蔗糖含量最高，为11.94~18.09 mg/mL，含量最低的为糯玉米汁0.12~0.34 mg/mL。在灭菌过程中，常规玉米和糯玉米汁中的果糖和葡萄糖含量均呈下降趋势，而甜玉米汁中三种糖随时间延长均表现为先上升后下降。甜味氨基酸和鲜味氨基酸为三种玉米汁的主要氨基酸，为总游离氨基酸的68.77%~80.20%。19种氨基酸在灭菌过程中含量变化经主成分分析得到相关性热图和主成分图谱，结果显示甜玉米汁和糯玉米汁中的氨基酸变化相似，均有6种氨基酸随灭菌时间延长含量上升，呈显著相关关系，而常规玉米汁中氨基酸变化与二者差别较大。结果为不同的鲜食玉米汁加工中品质调控提供参考。

Abstract:

Aimed at verifying the changes of taste-related components in fresh corn juice during autoclaving, milk-stage sweet corn, waxy corn and common corn juice were processed and the changes of sucrose, fructose, glucose and 19 free amino acids contents were determined using HPLC. Results showed that sweet corn juice had the highest sucrose content 11.94~18.09 mg/mL, while the waxy corn juice had the lowest value 0.12~0.34 mg/mL. During the sterilization, the fructose and glucose content in waxy corn and common corn juice decreased with the extending time, however, all the sugars in sweet corn juice increased first and then decreased. Sweet taste amino acids and umami amino acids were the main amino acids in the corn juices, and they contribute 68.77%~80.20% of the total amino acids. Moreover, the relationships of the 19 amino acids during sterilization were displayed using heat maps and principle component analysis (PCA) profiles. The changes of amino acids in sweet corn juice were similar to those in waxy corn juice. Both of them had six amino acids that increased during sterilization and showed significant correlations, which was different in common corn juice. These results would contribute to fresh corn juice quality improvement during processing.