Effects of vacuum microwave dehydration on the off-flavour intensity, functionality and nutritional properties of pea and soy protein isolates


 Philip Pui-Li Yen1, Anubhav Pratap Singh1

1 Food Nutrition and Health Program, Faculty of Land and Food Systems, The University of British Columbia, 2205 East Mall, Vancouver, BC V6T 1Z4, Canada.


Plant-based foods are increasingly preferred in lieu of animal-based foods, driving Canadian food industry to incorporate plant proteins into food formulations. However, raw plant proteins may have grassy off-flavours, and their functional and nutritional properties are often inferior to those of animal-based proteins. Direct steam injection may reduce the off-flavour intensity of plant proteins, but may impart a cooked off-flavour and decrease nutrient content, hence an alternative must be investigated. Thus, my research will explore vacuum microwave dehydration, as the efficient volumetric heating of microwaves, coupled with a large vapour pressure differential caused by the vacuum, may remove the off-flavour causing volatiles with little to no thermal deterioration. The overall objective of my research is to develop a vacuum microwave dehydration process for removal of off-flavours and improvement of functional and nutritional properties of pea and soy protein isolates used in non-dairy yogurts. Moisture content, microwave power and vacuum pressure will be adjusted according to a 3 factor, 5 level central composite rotatable design. Organoleptic properties (off-flavour intensity), functionality (solubility, emulsifying capacity/stability, sulphur group content, surface hydrophobicity) and nutritional properties (protein content, amino acid composition) of the plant protein isolates will be optimized using response surface methodology. Three optimal samples will be incorporated into non-dairy yogurts and subjected to accelerated shelf-life testing and sensory evaluation. By using vacuum microwave dehydration, off-flavours may be removed with no deleterious effects on quality. Thus, more high-protein, plant-based products can be produced, improving consumer health, augmenting agricultural sustainability, while bolstering the Canadian plant-based market.

Supported by Daiya Foods Inc.