Production of probiotic sweet lime juice powder: process optimization, quality assessment, and storage stability

The present study aims to optimize process parameters for spray drying of citrus fruit juice, i.e., sweet lime (Citrus limetta), using response surface methodology. The independent variables were maltodextrin concentration (5-15% w/v), inlet temperature (120-180 °C), and feed rate (10-25 mL/min), while the dependent variables used for optimization were drying yield and retention of vitamin C. The optimal conditions for producing sweet lime juice powder were 150 °C inlet temperature, 15% w/v maltodextrin concentration, and 19 mL/min feed rate, resulting in a maximum powder yield of 17.5% and greater vitamin C retention (21.8 mg/100 g). The study also examines the effect of inlet air temperature (120, 150, and 180 °C) on encapsulation efficiency and viability of probiotic microorganism Lactobacillus plantarum subspecies plantarum, incorporated in sweet lime juice. The probiotic powder produced at 150 °C showed 76.87% encapsulation efficiency and good powder properties with quicker rehydration time (57.5 s). Storage studies of probiotic sweet lime juice powder showed that refrigerated (4 °C) temperature well protected the viability of Lactobacillus plantarum (≥ 10⁸ cells/g) with better powder quality for 45 days compared to storage at room temperature (~ 25 ºC).