Utilization of soy processing by-products in foods
Alphonsus Utioh & Lindsey Boyd
Food Development Centre
- Develop processing methods to modify soy press cakes into formats suitable for development of novel food prototypes.
- Review regulations on the use of soy by-product and its modification methods for inclusion in food.
- Develop one of the food product prototypes and determine the nutritional composition and then assess its acceptability with a consumer panel.
- The use of cold pressed soy press cake in food applications increases the market value of a by-product mainly sold as animal feed; resulting in benefits to soybean producers and processors.
- The incorporation of fermentation into the processing of soy press cake creates a more functional ingredient with potential health benefits and helps reduce the beany flavour for use in food product development.
- The development of new food uses for soy press cake can increase its market value which would in turn increase the demand for farmers to grow soybeans.
Soybeans are a major crop grown in Canada and are processed into a wide variety of foods such as oil, soy milk, flour, miso and soy sauce. Soybean oil processing produces a large amount of soy press cake as a by-product, which typically is sold as animal feed. Soy press cake is high in nutrients including protein, fibre, residual oil, and micronutrients which have been linked to health benefits. Some health benefits of soybeans include reduced risk of cardiovascular disease and cancer. Fermentation of soybeans has been found to reduce unpleasant flavours like beany and bitter, as well as increase digestibility.
The activities and methods used in this project are designed using a systematic approach for developing and commercializing nutritious, tasty food products with potential health benefits. The aim of this research was to modify soy press cake using different pre-treatments, drying, milling and fractionation to create a high protein fraction that has improved physical and sensory attributes. The most desirable fractions obtained were then incorporated into a food application. The pre-treatments applied to the soy press cake included cold and hot water hydration, ethanol extraction, cooking and fermentation and then drum drying the slurry. The drum dried press cake was hammer milled and fractionated using different sieving equipment to try to concentrate the protein based on particle size. Particle size distribution, protein content, proximate composition and bio-active analyses were conducted. The protein content was not increased by any of the pre-treatments, except the ethanol extracted soy press cake due to the reduction in oil content. The protein content was 45% (dry basis) in the cooked and fermented fractions used for product development. The cooked and fermented soy press cake flours/fractions (<149 µm) had better solubility and reduced beany and grassy flavours which created greater opportunities for product development. The cooked and fermented soy press cake flours were made into Asian and garlic flavoured soy hummus dip products, respectively. These products were developed as a dip mix single use package in which the consumer would add oil and water to create a hummus-like product. The products had a smooth mouth feel, pleasant flavour and a texture that facilitated a dipping action for crackers or vegetables. A prototype recipe, nutrition facts table, and a consumer recipe for blending the hummus were developed in this project.