Enhancing functional attributes of rice protein concentrate through Aspergillus awamori MTCC 6652 assisted solid-state fermentation: Development of value-added vegan smoothie

Abstract

The study investigated the effects of solid-state fermentation using Aspergillus awamori MTCC 6652 on rice protein's functional properties, characteristics, and application in product formulations for varying durations (48, 72, and 96 h). Fermentation for 72 h notably enhanced the RPC's protein content by 7.83 % and improved its color profile towards lighter shades, evidenced by increased L* values and decreased a* and b* values, indicative of enzymatic degradation and pigment alteration, particularly notable after 96 h. Enhanced functional properties were observed at 72 h of fermentation, including increased protein solubility (by 9.8 %), oil and water holding capacity (by 14.33 % and 18.96 %, respectively), foaming capacity and stability (by 14.03 % and 14.11 %, respectively), and emulsifying capacity and stability (by 5.047 % and 5.69 %, respectively). Structural changes in fermented rice protein were observed through scanning electron microscopy, indicating alterations induced by A. awamori MTCC 6652. Fourier transform infrared spectroscopy and thermogravimetric analysis show shifts in peak positions and increased thermal stability of Fermented RPC. Additionally, microbial analysis of smoothie samples containing fermented protein showed increased microbial counts over storage time. Sensory analysis revealed comparable attributes between fermented protein-incorporated smoothies and standard smoothies initially, with slight reductions over time. This study emphasizes the considerable impact of fermentation on rice protein's properties and its potential in smoothie formulations. Overall, these findings highlight the significant impact of fermentation on the structural, chemical, and sensory properties of rice protein, thereby expanding its potential applications in smoothie formulations and potentially other food products.