Optimization of process variables viz., temperature and time for vacuum concentration of pitahaya (Hylocereus polyrhizus) fruit juice, its effect on total soluble solids, water activity, total betalain content and antioxidant activity

The objective of the study is to optimize the process parameters viz. temperature and time for the concentration of pitahaya juice. It investigates the influence of temperature and processing time on the vacuum concentration of H. polyrhizus juice in rotary evaporator. Through systematic experimentation and statistical analysis by Response surface methodology (RSM), using Central composite design (CCD). Key parameters such as total soluble solids (TSS), water activity, total betalain content, and antioxidant activity were evaluated. Results indicate significant effects of temperature and time on these parameters, with optimal conditions identified for maximizing TSS (60 ˚C and 174.34 min), betalain content (60 ˚C and175.40 min), and antioxidant activity (55 ˚C and 150 min) while minimizing water activity (60 ˚C and 180 min). Statistical modelling confirms the reliability of the findings, offering practical insights for optimizing the vacuum concentration process of H. polyrhizus juice to enhance its quality and handling efficiency.