Quality improvement of plant protein isolates – SensoLeg

Determination of the cause of the bitter-astringent taste of plant protein isolates and identification of technological parameters for quality improvement

Protein isolates are widely used for their emulsifying, foam-forming, and water-binding properties for the manufacture of a variety of foods including baked goods, soups, sauces, and sausage products. Up until now animal proteins such as casein/caseinate, whey protein, and egg powder have been largely used, even though plant proteins are more sustainable raw materials and are economically more attractive. The use of plant proteins has, however, been held back hitherto by their unacceptable taste. Plant protein preparations, besides having a bean-like and grassy flavor, are often also very bitter and astringent and in general have a dull and unharmonious taste impression compared to animal proteins. Depending on the food, these off-flavor attributes can dominate, limiting the use of plant protein preparations in foods or requiring the addition of masking agents.

There is a growing need for high-quality protein proteins with favorable sensory properties for various food applications. The SensoLeg project aims to analyze protein concentrates and isolates from peas, soybeans, and rapeseed which have a bitter/astringent taste. The orosensory active molecules will be identified using fractionated taste dilution analysis. The acquired knowledge will be used to optimize the processing steps (deoiling, extraction, precipitation/filtration) for manufacturing protein preparations. Improved protein ingredients with less bitterness/astringency will result. Application studies will then be undertaken with the improved protein ingredients. New uses for the proteins in the food industry will also be explored. Furthermore, simplified analytical methods will be developed to allow small and medium-sized companies to analyze ingredients for key bitter and astringent components so allowing rapid and reliable quality evaluation of commercially available protein preparations.