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

A mixed fruit beverage was formulated according to D-optimal mixture design using apple ber juice(X_(1),45-59%v/v)-an underexplored fruit,carambola juice(X_(2),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℃ for 1-5 min)were studied on various attributes of the mixed beverage.The beverages processed at 90℃ 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℃/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℃/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.