非浓缩还原(NFC)苹果汁加工过程中糖酸风味组分和呼吸速率的变化

Changes of Soluble Sugars,Organic Acids and Respiration Rates of Not-from-concentrate Apple Juice in Different Processing Stages

通过测定NFC苹果汁、固酸比以及糖酵解途径、三羧酸循环途径、磷酸戊糖途径、细胞色素途径和交替途径等的呼吸速率的变化,明确NFC苹果汁加工过程中影响糖酸风味品质的关键环节和转化的大致途径,为优化NFC苹果汁生产工艺提供依据。结果表明,NFC苹果汁加工过程中风味品质变化可分为原料到榨汁和灭酶到灌装两个阶段。第一个阶段,可溶性糖中的葡萄糖和山梨醇含量升高了49.12%和20.59%,有机酸中的苹果酸含量升高了8.06%、草酸含量显著降低了7.01%,TCAC呼吸速率升高0.64倍,CP呼吸速率降低0.85倍;第二个阶段,果糖、葡萄糖、苹果酸、草酸含量和固酸比的变化呈正态分布,与EMP途径、TCAC途径和AP途径的呼吸速率变化相关。因此,各加工环节对于果汁糖酸风味组分和呼吸速率的影响是不同的,热处理是NFC苹果汁加工过程中风味品质调控关键环节,应加强调节该环节果汁中心代谢酶促反应以优化糖酸风味品质。

The changes of sugar and acid flavor substances and respiratory rate of Embden-Meyerhof-Parnas,Tricarboxylic Acid Cycle Pathway,Pentose Phosphate Pathway,Cytochrome Pathway and Alternative Pathway in samples of Non-From-Concentrate(NFC)apple juice processing including raw materials,juice extraction,enzyme inactivation,homogenization,ultrasound,sterilization,and canning were detected.Then,the key links affecting flavor quality and the approximate ways of flavor substance conversion during fruit juice processing were clarified and the basis for further optimizing the industrial production process of NFC apple juice processing was provided.The results showed that the flavor quality change during NFC apple juice processing could be divided into two stages:from raw material to the juice squeezing section and from the enzyme inactivation to canning.In the first stage,the contents of glucose and sorbitol were increased by 49.12%and 20.59%,respectively,the content of malic acid was increased by 8.06%,the content of oxalic acid was decreased by 7.01%,the respiratory rate of the TCAC pathway was increased by 0.64 times and CP was decreased by 0.85 times;In the second stage,the changes of fructose,glucose,malic acid and oxalic acid content and total soluble solid/titratable acidity were normally distributed,which were related to the changes of EMP,TCAC and AP respiration rate.Therefore,the effects of different processing stages on the sugar acid and acid flavor components and respiratory rate of the fruit juice are different.Heat treatment is the key link of controlling flavor quality during NFC apple juice processing.The central metabolic enzymatic reaction of the juice should be strengthened to optimize the flavor quality.