Impact of fruit powders incorporation on probiotic viability and sensory properties of yogurt

Abstract

Purpose

The primary objective of this study was to investigate the viability of Lacticaseibacillus rhamnosus GR-1 (LGR-1) when combined with four prebiotic-rich fruit powders – apple, papaya, mango, and red beetroot – in probiotic yogurt. Additionally, the study aims to assess customer acceptability of the yogurt fortified with these fruit powders through a sensory evaluation using a nine-point hedonic scale.

Design/methodology/approach

The yogurt samples, inoculated with the LGR-1 probiotic strain, underwent fermentation at 38 °C for 0, 2, 4 and 6 h. Following fermentation, the samples were stored in a refrigerator at 4 °C for 1, 15 and 30 days. Throughout the study, microbial counts and pH level measurements were performed to assess the viability of LGR-1. A sensory evaluation consisted of 89 participants. A nine-point hedonic scale, ranging from 1 (dislike extremely) to 9 (like extremely), along with a questionnaire were used to assess criteria such as appearance, flavor, texture and overall acceptability of the samples.

Findings

All treatments at all time points maintained a minimum viable microbial count of 10⁷ CFU/mL (colony-forming units per mL), which indicated that the addition of fruit powders supported the growth and survival of LGR-1 in yogurt. Treatment 5, fortified with papaya powder, was the only group that exhibited a significant change of microbial count after 30 days of fermentation (p = 0.018). Although there were no statistically significant differences in pH values at the 0- and 2-h time points within each treatment, the pH remained relatively stable after day 15, with an average mean pH of 4.29. Treatment 2 fortified with mango powder obtained the highest overall acceptability score because of its smooth and firm texture as well as mild mango-sweet flavor.

Originality/value

This study explored the viability of probiotics and the sensory properties of yogurt fortified with various fruit powders, while also examining the potential prebiotic effects of fruit powders in enhancing overall sensory appeal. The findings suggested that papain may play a role in increasing probiotic viability in yogurt. Given the inconvenience and inaccessibility of fresh fruits and the generally inadequate prebiotic intake, this research addressed the gap in prebiotic consumption by offering novel ideas for health-enhancing dairy products.

Citation

Cao, Y., Fang, Y. and Hekmat, S. (2024), "Impact of fruit powders incorporation on probiotic viability and sensory properties of yogurt", Nutrition & Food Science, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/NFS-06-2024-0195