Vacuum microwave dehydration decreases volatile concentration and soluble protein content of pea (Pisum sativum L.) protein

BACKGROUND Peas are an inexpensive yet nutritious and sustainable source of protein. However, it is challenging to incorporate pea proteins into food formulations owing to their beany or green off-flavours and their limited water solubility. RESULTS Vacuum microwave dehydration (VMD) of pea protein with an initial moisture content of 425% (dry basis, db) at 2 W g(-1)specific microwave energy and 200 Torr vacuum level for 88 min led to an 83% reduction in total volatile compound concentration. VMD processing at high initial moisture contents facilitated the Maillard reaction, enhancing the extent of protein cross-linking, leading to a marked decrease in soluble protein content, to 11 g kg(-1). Reducing the initial moisture content to 56% db greatly retained protein solubility (112-113 g kg(-1)), but it only led to a minor reduction in total volatile compound concentration (2-11% reduction). A high microwave energy (20 W g(-1))-short time (2 min) treatment at 200 Torr vacuum level was found optimal, reducing both volatile levels and soluble protein content by similar to 50%. CONCLUSION Evidently, it is difficult to employ VMD without reduction of pea protein solubility and corresponding changing in functionality. Yet, if optimized, VMD has the capability to decrease volatile concentrations while retaining protein solubility. Future sensory analysis should be conducted to determine whether the aforementioned reductions in total volatile compound concentration may have a notable effect on consumer palatability. (c) 2020 Society of Chemical Industry

Automated summary

The study demonstrates that vacuum microwave dehydration can reduce volatile compound levels in pea protein, with high initial moisture content facilitating the Maillard reaction but decreasing soluble protein content. Short-time, high-energy treatment under specific conditions is an effective method for reducing volatile levels while also decreasing soluble protein content. Future sensory analysis is needed to determine the impact of reduced volatile compound concentration on consumer palatability.