Response Surface Optimization and Impact of Immobilized Enzymes Naringianse and Tannase on the Quality Parameters of Citrus maxima Juice

Abstract

Pomelo has been reported as a rich source of flavanone glycoside with antioxidants and exhibits favorable health effects such as antimicrobial, anti-inflammatory, antiatherogenic, antitumor, and anti-clotting activity. Despite all the beneficial health impacts of Citrus maxima, it still has lower commercial value because of its juice's bitterness due to the presence of naringin and tannic acid. Therefore, an attempt has been made for the cost-effective and economic debittering process using naringinase and tannase enzymes. The 17 experiments were planned according to RSM, BBD to analyze the effect of independent variables with three levels of each, i.e., Enzyme ratio ((Naringinase: tannase) (100:0, 50:50, 0:100)), incubation temperature (30°C, 40°C, 50°C) and incubation time (2, 3, 4 hrs) on physicochemical quality of Citrus maxima Juice. The study's result indicated that independent variables affected the responses (pH, TSS, TA, Naringin content, Tannin content, TPC, and Vitamin C content). Optimization was done using Design Expert 10.0.1 software to debitter and clarify citrus maxima juice by immobilized enzymes. The optimum values were found to be 54.55, 50°C, and 4 hrs. The values for pH, TSS, TA, Naringin content, Tannin content, TPC and Vitamin C content were found to be 3.17, 6.256 °Brix, 0.885 %citric acid , 220.549 μg/ml ,0.311mg/ml, 1256.721 mg GAE/L,30.309 mg/100ml respectively. From the study, it could be concluded that the maximum debittering and clarification of citrus maxima juice could be done under processing conditions, i.e., enzyme ratio 50:50, incubation temperature 50°C and incubation time 4 hrs.