Metabolomic profiles of not from concentrate orange juice after different sterilization treatments based on HS-SPME-GC-MS and UPLC-QTOF-MS.

Not from concentrate (NFC) orange juice is minimally processed, natural-appearing food, and has become more popular. Sterilization is an important stage for NFC orange juice production. Here we present a comprehensive analysis of the effect of sterilization on the metabolites of NFC orange juices, including three thermal (pasteurization, high-temperature short time, and ultra-high temperature) and one nonthermal (high hydrostatic pressure) method. A total of 108 metabolites, including 59 volatiles and 49 nonvolatiles were identified in orange juice. Of which, only butyl butanoate and 3-carene were detected in fresh orange juice. Sterilization significantly changed the metabolites of orange juice, and different methods caused various changes. Esters were downregulated by both thermal and nonthermal sterilization, while most flavonoids and terpenes were upregulated. With comparative analyses of three thermal sterilization, we found that high temperature and relatively short-time treatment preserved esters and ascorbic acid more effectively than low temperature and prolonged treatment. Aldehydes, however, were the opposite. Nonthermal sterilization is effective in preserving the metabolites of orange juice, especially for esters, terpenes, and flavonoids. In addition, 19 distinct metabolites were characterized between thermal and nonthermal samples by chemometrics analysis. These findings provide a new sight of the optimization of sterilization methods and references for different types of NFC orange juice identification. PRACTICAL APPLICATION: This study provides a reference for the optimization of sterilization methods and identification of HHP and thermal NFC orange juice and also benefits the purchase of consumers.