Comparative analysis of the prebiotic potential of different flours compared to inulin

Abstract

Prebiotics are non-digestible food components that promote the growth and health of beneficial bacteria in the gut. This has the potential to increase the host’s health. Inulin is a widely studied prebiotic, but interest is growing in alternative plant-based sources. The objective of this study was to investigate and comparatively evaluate the prebiotic potential of yellow sweet potato flour, jackfruit bulb flour, banana pseudo-stem core flour, and sugarcane residue flour, using inulin as a reference, to identify new, sustainable sources of prebiotics. The prebiotic potential was determined by analysing the crude fibre content of the flours and performing fermentation experiments with Lactobacillus rhamnosus cultured in MRS (DeMan, Rogosa, and Sharpe) broth. Optical density (OD) readings were taken to monitor microbial growth at 0, 4, 6, and 24 hours after inoculation. The yellow sweet potato flour exhibited the highest prebiotic activity with an OD value of 0.83±0.02 Abs (10−1 dilution) after 24 hours post-inoculation, suggesting that yellow sweet potato flour has high potential as a source of prebiotics. According to the optical density measurements, banana pseudo-stem core flour observed microbial growth in the early stage of fermentation. The microbial growth in the banana pseudo-stem core flour stabilised by 24 hours, indicating that banana pseudo-stem core flour could be beneficial for short-term promotion of gut health. Sugarcane residue flour, which has a high crude fibre content (25.83%), displayed slower but sustained microbial growth that could be attributed to its increased fibre content, which takes a longer time for microbial digestion. Jackfruit bulb flour displayed moderate prebiotic activity, corresponding with its lower crude fibre content. These flours were also analysed using Fourier Transform Infrared Spectroscopy (FTIR), which revealed broad hydroxyl and glycosidic bond peaks indicating fermentable carbohydrates, together with carbonyl, protein, lipid, and lignin signals, confirming the complex bioactive composition and prebiotic potential of the flours. The data were statistically analysed, indicating that the flours and fermentation times were significantly different, with the results showing the superior performance of yellow sweet potato and banana pseudo-stem core flours. The findings suggest that these alternative flours could serve as prebiotic sources, supporting dietary diversity and gut health.