Microwave‐assisted enzymatic extraction of plant protein with antioxidant compounds from the food waste sesame bran: Comparative optimization study and identification of metabolomics using LC/Q‐TOF/MS

Abstract

This study aimed to investigate the effects of microwave-assisted and combined microwave-assisted enzymatic extraction techniques for the recovery of plant-based protein and antioxidant compounds from the food waste sesame bran. The effects of independent variables, that is, process temperature (25–55 °C), time (10–120 min), and enzyme concentrations (0.12–2.40 AU/100 g) were examined using a central composite design by the response surface methodology and were all found to have significant effects on protein yield, total phenolic content, and antioxidant capacity values. Optimal process conditions for microwave-assisted extraction were 51 °C process temperature and 29 min time; and for combined microwave-assisted enzymatic extraction were 1.94 AU/100 g enzyme concentration, 49 °C, 98 min. Protein fractions of extracts by SDS-PAGE, cellular structures of sesame brans by the scanning electron microscope, and identification of protein subunits and phenolic compounds by LC/Q-TOF/MS analyses were also inspected and compared with a standard alkaline method. Practical applications Cereal and oilseed by-products like brans have gained great importance in food technology due to their valuable protein contents. Recently, several attempts were performed to recover plant-based protein from various food wastes. Sesame bran is an unevaluated agro-industrial by-product and is a potential source of plant protein with phenolic compounds possessing functional properties. Latest studies showed that sesame processing plants reveal a huge amount of bran which have valuable compounds such as sulphur-containing amino acids. This study shows that highest recovery rates of plant-based protein with bioactive compounds from sesame bran could be achieved by the microwave-assisted enzymatic extraction technique. Obtained protein isolates could be evaluated in functional food developments. Results of this study could be an insight into researchers and food technologists who like to carry out studies on similar subjects.