Functional and Healthy Yogurts Fortified with Probiotics and Fruit Peel Powders

The application of processing waste by-products along with probiotics is an interesting choice to confer potential functional aspects to food products. This study was designed to investigate the nutritional capacity of freeze-dried mango peel powder (MPP) and banana peel powder (BPP) in the presence of a mixture of three probiotic species (1% of each of three probiotics (Lacticaseibacillus casei (431®), Lacticaseibacillus rhamnosus (LGG®) and Bifidobacterium subsp. Lactis (Bb-12®)) as sources of additional nutrients and prebiotics in fresh and rehydrated freeze-dried (RFD) yogurts for 28 days of refrigerated storage. The net count of probiotics in yogurt fortified with MPP and BPP increased by at least 1 log CFU/g after 4 weeks of refrigerated storage. Adding fruit peel powder (FPP) significantly (p < 0.05) increased fat, ash, and protein contents in both fresh and RFD yogurts in comparison with the control yogurt. Similarly, the total phenolic contents (TPC) and antioxidant activity (AOA) was enhanced significantly (p < 0.05). The TPC reached 2.27 ± 0.18 and 2.73 ± 0.11 mg GAE/g in RFD enriched with BPP and MPP compared to a TPC of 0.31 ± 0.07 mg GAE/g in the control. Additionally, yogurt samples enriched with BPP (Y-5) and MPP (Y-6) demonstrated 12% more sugar contents than non-fortified yogurts (Y-1). Higher titratable acidity and lower pH values were also recorded in the RFD yogurt. Significant differences (p < 0.05) in the color parameters were detected in both fresh and RFD yogurts with reduced brightness (L*) and increased redness (a*) of the product. These findings demonstrated the suitability of MPP and BPP in yogurt formulations to optimize the advantages of such synbiotic products with higher availability of phenolic compounds.

Development of rice based probiotic yogurt enriched with some fruit pulps and its quality analysis

Yogurt is one of the popular dairy products produced by the bacterial fermentation of milk. Researches proved that fruit enriched Rice-based yogurt is good alternative for the traditional yogurt. Hence, four different combinations of rice-based yogurt were prepared by adding rice slurry. Rice-based yogurt containing 25% milk and 75% rice slurry scored best in microbial analysis. Count of both Streptococcus salivarius ssp. thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were higher in this combination but organoleptic quality was poor. The one with 75% milk and 25% slurry scored best in organoleptic analysis as it scored high in all the characters under study. Hence the combination with 75% milk and 25% slurry was selected and was enriched with the fruit pulps of Annona, Papaya and Guava. The one with 20% Annona fruit pulp and one with 5% Papaya fruit pulp were selected as the best combinations as they got the highest overall acceptability score and the count of both the bacteria were higher in these combinations, proved that fruit enrichment doesn't affect bacteria in yogurt. Cost analysis proved that collection of fruits from wild will help to reduce the price of the yogurt. Thus, Rice-based Probiotic Yogurt with 75% milk and 25% rice slurry with 20% Annona fruit pulp and one with 5% Papaya fruit pulp were developed as best combinations and can replace normal yogurts currently available in the market with low cost.