Evaluation of the effects of pasteurization temperature and holding time on the quality of red-flesh dragon fruit (Hylocereus polyrhizus) - strawberry (Fragaria × ananassa) juice

Abstract

This study was conducted to evaluate the effects of pasteurization temperature and holding time on the quality of red-flesh dragon fruit (Hylocereus polyrhizus) - strawberry (Fragaria × ananassa) juice. The juice was blended at a ratio of 7:3 (v/v), treated with pectinase enzyme, supplemented with sugar and ascorbic acid, and subsequently pasteurized at three temperature levels (80, 85, and 90 °C) for corresponding holding times (3, 5, and 7 minutes). The evaluated parameters included pasteurization unit (PU), inhibition efficiency against aerobic bacteria, yeasts, and molds, betacyanin and vitamin C content, as well as sensory quality. The results demonstrated that both pasteurization temperature and holding time had significant impacts on all examined criteria. Among the tested conditions, pasteurization at 85 °C for 5 minutes achieved a PU ≥ 5, ensured microbiological safety, and preserved the characteristic color, natural aroma, and high nutritional value of the product. Therefore, this condition was identified as optimal for producing red-flesh dragon fruit - strawberry juice with desirable sensory properties, high nutritional retention, and appropriate microbiological stability.