Optimization and investigation on physicochemical, microbial and sensory quality of permeate-based probiotic orange beverage

Permeate (PM) is a by-product produced from milk or whey ultrafiltration process. Due to its flavour off-notes, little attention has been given by food manufactures and researchers. To increase nutritional value of PM and their conversion to forms that are suitable for human consumption, production of probiotic juice beverage is one of the best choice. By this way, an economical product with appropriate functional properties and beneficial health can be produced. At the beginning, formulation of PM non-probiotic fruit beverages were optimized using Response Surface Methodology founded on central composite design. Based on primary experiments, PM (12.95-97.04ml), water (19.7770.22ml) and orange juice concentrate (5.95-16.04g) were selected as the constant factors. Formulation of orange juice was optimized based on 45.63 ml, water; 38.75 ml PM; and 14 g orange juice concentrate, respectively. At the next stage, the best sample was inoculated with Lactobacillus acidophilus (LA5) and were kept on refrigerator (4°C) till the end of storage. Antioxidant capacity (amounts of anthocyanin, total phenol, Trolox, Frap and vitamin C), probiotic cell counts and physicchemical and sensory attributes of probiotic beverages were monitored during a 28-day storage period. Probiotic fruit beverages had high probiotics bacteria count (>107 cfu/ml) at the beginning till the end of storage. After 28 days storage, the amount of total phenol, Trolex, Frap and vitamin C of probiotic PM juice was recorded as 22.48mg/100 g, 1.48µmol/g, 3.63 mol/g and 7.3mg/100g, respectively.