Development and shelf-life evaluation of drinking yogurt enriched with encapsulated probiotics

Abstract

Encapsulation is an effective approach to deliver probiotics to consumers without compromising their viability. Probiotics are sensitive to processing, storage and gastrointestinal tract conditions, often leading to cell death during production and ingestion. The study aimed to develop drinking yogurt enriched with encapsulated probiotics. Probiotics were obtained from a commercial starter culture and identified through Gram staining and catalase test. The isolated probiotics were encapsulated using the spray-drying method. Viable cells within the encapsulated beads were determined by breaking the beads with a sodium citrate solution (2% w/v, pH 7), and encapsulated probiotics were incorporated into drinking yogurt. Yoghurts were stored at 4°C for 13 days and analysed for total plate count, yeast and mold count and pH. The isolated bacteria produced cream color colonies with entire margins, were Gram-positive and catalase-negative. Encapsulated probiotics showed significantly higher survival at acidic pH (pH 3) compared to free cellswith counts of 6.44 ± 0.09 log10 CFU/mL at pH3 and 7.39 ± 0.12 log CFU/mL at pH7, compared to the control (6.28 ± 0.03, 7.36 ± 0.01 log CFU/mL). Both yoghurt samples showed a significant pH decrease over the 13-day storage period. Probiotic viable cell count increased significantly from day 1 to 13 for both control and encapsulated yoghurt samples. On day 13 encapsulated probiotic yogurt recorded a higher count (6.21 ± 0.14 log CFU/mL) than the control (6.01 ±0.10 log CFU/mL), thought, the difference was not > 2 log CFU/mL. Lactic acid bacteria counts did not change drastically, suggesting the encapsulated probiotics remain intact without being released into the yoghurt matrix, potentially enabling delivery to the large intestine. The encapsulation efficiency was 86.78%. No yeast or mold growth was detected up to day 13 confirming the products shelf life.In conclusion, drinking yogurt enriched with encapsulated probiotics to consumers.