A comparative study of the cloudy apple juice sterilized by high-temperature short-time or high hydrostatic pressure processing: shelf-life, phytochemical and microbial view

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.

Keywords:
cloudy apple juice; shelf life; high hydrostatic pressure sterilization; high-temperature short-time sterilization