Characterization and valorization of soybean residue (okara) for the development of synbiotic ice cream

There is an increasing challenge in probiotic viability and stability during food product formulation, processing, and storage. However, synbiotic functional foods have promising potential to deliver the targeted benefits. This study aimed to isolate the okara from soybean residue, and obtained okara flour was further characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Synbiotic ice cream was developed by fortification with Lactobacillus rhamnosus GG and okara at different concentrations (1-3%). Additionally, the synbiotic ice cream was subjected to physicochemical and sensory attributes over 60 days of storage. High viability of L. rhamnosus GG (8.17 log CFU/mL) was observed during storage at 3% okara. Moreover, adding okara at 2% or higher improved viscosity, reduced overrun, and maintained probiotic viability. When compared to the control (ice cream without okara), synbiotic ice cream exhibited a higher protein content and a lower fat level. The synergistic combination of probiotics and okara in ice cream is a potentially novel approach for developing functional ice cream. The addition of okara is not only helpful in increasing the nutritional value of the ice cream but will also be a way forward to minimize agricultural waste. Synbiotic ice cream developed in this study may be considered a potential functional food rich in protein and low in fat.