Storage Stability of Chinese Bayberry Juice after High Pressure or Thermal Treatment

Abstract

The effect of high pressure (HP) and thermal (TP) treatments on storage stability of Chinese bayberry juice was investigated. Samples were treated for 5 min at 500 MPa (HP treatment) at room temperature or in a water bath (TP treatment) at 55C for an effective time of 8 min and stored at 4 and 25C. The soluble solids content of the HP- and TP-treated samples was stable at both temperatures, while it decreased at 25C in control samples. Color retention was better in the HP-treated samples than in TP-treated samples. Anthocyanin retention values in the HP- and TP-treated samples were 96.5 and 85.1%, respectively, while ascorbic acid retention values were 89.2 and 58.3%, respectively. Anthocyanin and ascorbic acid degradation during storage followed a first-order kinetics, and the rate constants were lowest for the HP-treated samples followed by TP treatment and were highest for the control samples. Practical Applications Chinese bayberries (Myrica rubra Sieb. et Zucc.) are highly susceptible to mechanical injury and microbiological spoilage, which limits their postharvest life even at refrigerated conditions. Extraction of bayberries to juice followed by thermal treatment is a practical process for shelf life extension. The juice has a strong antioxidant capacity because of its anthocyanin, phenolic and ascorbic acid contents. Consumption of fruit and vegetable juices containing anthocyanins and ascorbic acid can contribute to reducing the severity of various degenerative diseases. However, anthocyanins and ascorbic acid are very sensitive to heat. Thermal processing may cause detrimental quality changes. High pressure processing is one of the promising novel nonthermal techniques with potential for better retention of color, flavor and nutritional parameters of food. Our study showed that high pressure treatment was more efficient in preserving some physicochemical properties of Chinese bayberry juice as compared to thermal treatment. This work provides relevant information for further study of Chinese bayberry juice.