A novel process for synthesis of soybean protein hydrolysates and study of its effectiveness as a biostimulant and emulsifier

Abstract

We study in extensive detail synthesis of protein hydrolysates (PHs) from soybean meal (SBM) using high shear stator-rotor impeller. The effects of alkali concentration, soaking and shearing time, SBM loading and combination of soaking and shearing on the extent of SBM hydrolysis and protein/amino acid concentration are elucidated. Effectiveness of soybean protein hydrolysates (SPHs) as a plant-based biostimulant and as an emulsifier for the synthesis of oil-in water emulsions was investigated. Use of a high shear mixer and alkaline conditions resulted in up to 80% extraction of protein in 30 min at room temperature. Amount of protein extracted increased with NaOH concentration, SBM loading and shear mixing time. However, alkali concentration and application of shear mixer were dominant factors for maximum SBM hydrolysis and protein extraction. SPHs showed excellent biostimulant activity for wheat and fenugreek plants. Wheat and fenugreek plants which received SPHs treatment showed enhanced percent germination, survival and overall growth of the plants (shoot and root length and dry weight). SPHs stabilised oil-in water emulsions showed excellent long-term stability and its emulsifying properties were comparable with the similar emulsions stabilised by soy protein isolates.