Ultrasound and enzyme-pretreated extraction for the valorization of pea pod proteins

Pea pod (PP) is an agricultural by-product with 10%–13% protein content which has a potential to be converted to value-added ingredients. In this study, different protein extraction strategies including three different solvents (water, salt, and alkaline) and two different pretreatments (ultrasound [US] and enzyme such as pectinase and Viscozyme®) before conventional alkaline extraction were employed to maximize the extraction yield. The US-pretreated alkaline extraction achieved the highest yield (21.1%) in protein extracts under optimum conditions (30% amplitude for 5 min). PP protein concentrates showed significant differences in solubility, sodium dodecyl sulfate–polyacrylamide gel electrophoresis protein patterns, scanning electron microscopy images, and color depending on the applied extraction method. All PP residues after extraction still remained protein (5.2–8.0 g/100 g) regardless of the extraction techniques, representing the challenges in protein extraction from agricultural by-products with a lignocellulosic matrix. The combined use of US and enzyme treatments should be further investigated for higher extraction yields. Practical Applications: Agricultural wastes and by-products could be potential protein sources; however, their lignocellulosic structure could be challenging for protein extraction. In the current study, different extraction strategies including ultrasound (US) and enzyme pretreatments were performed for the extraction of proteins from pea pods which is an agro-industrial by-product. Results suggest that US pretreatment may have promising applications for the extraction of valuable compounds from agricultural and industrial by-products, contributing to sustainable food processing strategies.