Passion fruit juicing with or without seeds treated by high-pressure processing and thermal pasteurization: Effects on the storage stability of enzymes and quality properties

This study evaluated the changes of enzymes and quality properties of passion fruit juice juicing with (PFJ-1) and without seeds (PFJ-2) treated by high-pressure processing (HPP, 600 MPa/5 min) and thermal pasteurization (TP, 85 °C /30 s) during storage at 4 °C for 35 days. Juicing with seeds resulted in PFJ-1 with 76.83, 68.25 and 28.12% higher activities of polyphenol oxidase, peroxidase and superoxide dismutase than PFJ-2, respectively, and its apparent viscosity at 10−1 s and L* were also 148.60 and 1.47% higher, respectively. The total sugars, organic acids, and volatile compounds in PFJ-1 were 9.16, 4.97 and 53.85% higher than PFJ-2, respectively. Quality properties, including sugars, organic acids, volatile compounds in PFJ-1-HPP were all more susceptible towards degradation than PFJ-2-HPP under storage, which were decreased by 21.93, 26.14 and 18.47% after storage. This research provided new insights for production of high-quality passion fruit juice. At present, the passion fruit juice is the dominated product in passion fruit industry, but there are few studies reported on the difference between the juice quality under different juicing methods by juicing with or without seeds. The seeds in passion fruit contains a great variety of substances such as oxidative browning enzymes, unsaturated fatty acids, which can significantly affect the quality of passion fruit juice after entering in juice. This research is of great significance as a theoretical basis to further research on the influence mechanism of enzyme and phytochemicals in seeds on the quality of passion fruit juice, and also provides a guide to production for quality orientated passion fruit juice based on consumer and producer demands.