Abstract Cloudy apple juice (CAJ) is popular due to its potential health benefits and pleasant flavor. However, the common used sterilization methods of CAJ by High hydrostatic pressure (HHP) or high-temperature short time (HTST) still showed many inadequacies. The present work studied the impact of HHP (400MPa/10 °C/10 min) and HTST (98 °C/50s) on CAJs made from a new cultivar Changfu 2 planted in Loess plateau area. We comparatively evaluated the microbes inactivation, enzymatic activity, phytochemical parameters, and sensory quality after the HHP and HTST treatment and during the cold storage (4 °C). Results showed that during the cold storage, both HHP and HTST treated CAJ showed a declining trend in sensory attributes like aroma, taste and overall acceptability. HTST showed a higher killing rate of bacteria, and the CAJ was detected a higher diversity of microorganisms (expressed as OTU) during the cold storage. At the end of shelf-life, Rickettsia, oxyphotobacteria, and pseudomonas were detected as the dominant genera in both HHP and HTST treated CAJs. Spearman bivariate correlate analysis determined the relationship between the bacterial profiles and enzymatic activity, phytochemical parameters, and sensory quality after the HHP and HTST treatment.

Abstract The authentication of fresh apple juice (FAJ) is a significant issue. However, the main characteristics of FAJ, diluted apple juice (DAJ) with added concentrated apple juice (DAJ+CAJ), and DAJ with added sucrose (DAJ+s) are not different when using classical chemical analyses in juice authentication. In this study, isotope ratio mass spectrometry (IRMS) was used to determine the δD, δ18O, and δ13C in adulterated apple juice for juice authentication. The δD and δ18O values were decreased in adulterated juice. A linear correlation was found between δD and δ18O in apple juices with different amount of adulteration. Therefore, this linear relationship can be used to determine the amount of adulteration that took place. The δ13C value and the content of each component in real apple juice are within specific ranges. The adulteration can be recognized once the δ13C value and the content of each component in the apple juice are out of these ranges. The implementation of this method would help maintain the juice market’s stability and protect consumers’ interests.

Abstract A direct steam injection pretreatment was added before the microwave-assisted extraction procedure for the extraction of flavonoids from seeds of Hovenia dulcis Thunb, and the antioxidant activity of flavonoid extracts was determined. Based on the experimental results, the addition of direct steam injection simultaneously increased the extraction yield of total flavonoids compared with direct microwave-assisted extraction, and antioxidant activity of flavonoid extracts obtained by adopting the steam injection pretreatment was higher than that by direct microwave extraction alone. Myricetin was isolated from the flavonoid extracts, and the structure was identified by infrared spectroscopy (IR), electrospray ionization mass spectrometry (ESI-MS), and 1H nuclear magnetic resonance (1H-NMR). Recovery yield of total flavonoids was increased by 11.63% when the direct steam injection pretreatment was added to direct microwave extraction.