(P19-020-25) Heat Moisture Treatment Alters the Physicochemical Characteristics of Proso Millet and Enhances Short- Chain Fatty Acids (SCFAs) Production in In-Vitro Fermentation

Objectives: To analyze the effect of heat moisture treatment on physico-chemical properties and microbial fermentability of Proso millet

Methods: Proso millet (Panicum miliaceum), flour was weighed in glass bottles. The moisture contents were adjusted to 20% (HMT-20), 30% (HMT-30), and 40% (HMT-40). The bottles were then sealed and allowed to equilibrate at room temperature. Subsequently, bottles were placed in hot air oven, at temperature 60, 80, 100 and 120^oC respectively for 4h, followed by cooling phase at 4^oC for 24hrs. Finally, the samples were dried at 45^oC overnight to a constant weight.

HunterLab's ColorFlex EZ was used to analyze the color changes in flours. The pasting property was determined by the Rapid Visco Analyzer. Resistant starch (RS) contents were quantified using Megazyme rapid resistant starch kit. Structural Changes were analyzed by FTIR analysis.

For in vitro fermentation, fecal samples were collected from 3 healthy human subjects. Control and modified flour samples were fermented with fecal samples for 48hs under anaerobic condition. SCFAs were analyzed by GC.

Results: No changes in color were observed in flours subjected to 60 and 80^oC however, browning was found in flours exposed to 100 and 120^oC. A gradual increase in pasting temperature was observed up to 40% HMT and 100^oC. At 120^oC, all samples lost their pasting properties and viscosity. RS contents increased significantly in HMT flour up to 100^oC compared to the control.  Maximum increase (25.3%, p< 0.05) was observed in HMT-20 at 80^oC.

In vitro fermentation studies demonstrated that despite the variability in SCFAs production across different donors a significant increase (Acetate 10- 43%, Propionate 5-23% and butyrate 10-45 %) was observed.

Conclusions: These findings suggest physical processing techniques can be used as an effective way to improve microbial fermentability of whole flour.

Funding Sources: We acknowledge USDA-NIFA grant 2022-67017-37184 funded to Dr. Reddivari. Dr Khan acknowledges Indian council of Medical Research- Govt of India for Long term international fellowship for biomedical research.