Oilcrop pomace as a source of vegetable protein

Abstract

Scientists predict that the demand for animal proteins will double in the next 25 years. The availabilit y of animal proteins is becoming increasingly problematic due to factors such as pollution, climate change, high energy consumption, and rising prices. Consequently, research into alternative, environmentally friendly protein sources is attracting increasing attention. Plant sources rich in proteins with favourable amino acid composition are particularly promising. Once extracted, these plant proteins can serve as food supplements, are easily digestible, non-toxic, and

suitable as substitutes for animal proteins. In addition, there is an increasing focus on addressing the problem of food waste by converting it into products suitable for human consumption. An

example of such agro-waste is oilseed pomace, a by-product of oil production that can be a valuable source of protein. Methods of extracting valuable proteins from oil refinery by-products using new technologies have been analysed. Depending on the method of oil extraction, the wastes are divided into two categories: pomace (residues after mechanical extraction) and cakes (residues

after chemical extraction). Despite the high oil yield of the chemical method, pomace is more valuable because it is not exposed to chemicals and is a more environmentally friendly product. In addition, pomace is rich in biological substances, minerals and vitamins. The chemical composition depends on the type of pomace, but it is mainly rich in phosphorus, magnesium, folic acid, tocopherol, thiamine, etc. To extract protein from the pomace, water, alkalis, saline solutions, organic solvents or acids

are usually used. The process starts with the alkaline solubilisation of proteins, after which insoluble substances such as starch and fiber are removed by centrifugation. The protein is then precipitated at the isoelectric point using hydrochloric acid. Spray drying is often used to obtain powdered concentrate, which is advantageous in that it avoids overheating the product, preserving its quality, and avoids the need for additional grinding. Modern methods aim to reduce the use of

chemicals, reduce temperature, shorten extraction time, and increase efficiency and protein yield. These methods include high-pressure treatment, microwave extraction, supercritical fluid extraction, ultrasonic extraction, cold plasma treatment, pulsed electric fields, and radio frequency treatment. The protein yield after extraction can reach 80% with lower phenolic content. The obtained concentrates are widely used as food supplements as a source of vegetable protein, have antioxidant properties and are rich in minerals.