Development of fermented beverage from whey and kinnow juice

Abstract

The dairy sector generates large quantities of whey as a residual byproduct, which poses environmental challenges due to its elevated
organic content. Converting this nutrient-rich effluent into functional
beverages represents an eco-conscious strategy for resource
valorization. This investigation focused on formulating a probiotic
beverage by integrating whey with kinnow (Citrus reticulata) juice, a
citrus fruit recognized for its high concentrations of vitamin C and
essential micronutrients. The aim was to develop a fermented
functional drink and systematically evaluate its physicochemical
attributes, sensory appeal, microbial integrity, and storage
performance. Six distinct formulations (T0, T1, T2, T3, T4, T5) were
produced using varying proportions of whey and kinnow juice, with
T0 (100% whey) designated as the control. Each blend was inoculated
with Lactobacillus acidophilus at 1% (v/v) and subjected to
fermentation at 37°C for a duration of 5 hours. Sensory analysis was
carried out by a panel of 10 individuals using a 5-point hedonic scale.
Among the treatments, T2 (70% whey, 30% kinnow juice) achieved
the highest acceptance scores, including 4.23 for taste, 4.05 for flavor,
3.98 for appearance, 3.86 for sweetness, and 4.02 for overall
preference. This formulation was characterized by 0.20% fat, 2.29%
protein, 390 mg/100 ml glucose, and 44.23 mg/100 ml ascorbic acid.
The initial pH and titratable acidity were measured at 4.43 and 0.57%,
respectively. Over 21 days of storage at 4 ± 1°C, pH decreased to 4.29
while acidity rose to 0.73%. Total viable counts remained above 10⁶
CFU/ml, indicating stable microbial levels during the study period.
These findings confirm the feasibility of T2 as a nutritionally
beneficial and environmentally sustainable probiotic beverage
derived from dairy by-products.