Effect of ohmic heating on protein characteristics and beany flavor of soymilk

Abstract

The functional and nutraceutical food market is growing at the fastest rate in all segments of food. Plant-based milk substitutes' popularity is increasing worldwide as these beverages are rich in functional and nutraceutical compounds. Soymilk is a highly consuming plant-based milk substitute rich in protein, vitamins, minerals and cholesterol-free. The novel ohmic heating technology was potentially applicable in improving protein characteristics with a reduction in beany, off-flavor of soymilk. Ohmic heating is rapid and uniform heating technology. Effect of ohmic heating voltage (160V, 180V, 200V) and target temperature (70 °C, 80 °C, 90 °C) on extraction yield, protein characteristics and the beany flavor were investigated. Maximum yield (83.25±0.17%) of soymilk was found at 200V and 90 °C. Ohmic heating significantly increased (p< 0.05) in crude protein content and soymilk's protein digestibility. The highest amount of protein content (8.14±0.08%) found at 180V and 80 °C. The digestibility of soymilk increased with an increase in temperature and voltage and found a maximum of 75.55±0.55% at 200V and 90 °C. The increase in voltage protein solubility decreased to 8.03±0.29%. The hydroperoxides responsible for beany flavor were significantly decreased (p< 0.05) with increasing temperature and found a minimum 0.47±0.02 meq/kg at 200V and 90 °C target temperature.