Development of a mixed fruit beverage and pulsed light treatment thereof to obtain a microbially safe and enzymatically stable product

Abstract

A mixed fruit beverage was formulated according to D-optimal mixture design using apple ber juice (X1, 45–59% v/v) - an underexplored fruit, carambola juice (X2, 1–20% v/v), and black table grape juice (X3, 35–40% v/v). The crisp overall acceptability (COA) from 16 semi-trained panelists and overall hedonic score (OSH) from consumers were estimated. The best formulation was apple ber: carambola: black table grape juices = 59.0: 3.5: 37.5 v/v with COA and OSH values of 3.23 (on a scale of 5) and 7.55 (on a scale of 9), respectively. Further, the efficacy of pulsed light (PL) (18–30 W cm−2 for 33–167 s; total fluence 600–5000 J cm−2) and thermal treatments (90 °C for 1–5 min) were studied on various attributes of the mixed beverage. The beverages processed at 90 °C for 5 min (thermal treatment) and 5000 J cm−2 (PL treatment at 30 W cm−2 for 167 s) showed no microbial count with a complete enzyme inactivation. The thermally pasteurized sample (90 °C/5 min) was more brown (browning index = 70.15) than the PL pasteurized beverage (browning index = 65.98). Interestingly, the PL pasteurized (5000 J cm−2) beverage showed 25%, 27%, and 19% more vitamin C, antioxidants, and phenolic compounds, respectively, than the thermally pasteurized (90 °C/5 min) beverage. The PL-treated beverage had a greater sensory appeal than the thermally treated beverage. PL-treatment can be an efficient non-thermal pasteurization treatment for ensuring complete microbial and enzymatic inactivation with maximal retention of nutritional and sensory attributes of the blended beverage.