Use of electronic sterilisation to increase the biological protein value and increase the shelf life of semi-finished oyster mushroom products
The question of the biological value of mushroom protein is not limited to the study of its composition. In addition, the associated problem of its digestibility and assimilability is widely discussed in the scientific community, including in the scientific publications discussed in this article. Mycoprotein derived from protein-rich unicellular fungi biomass is commonly used in contemporary food-production processes. In Russia, however, an alternative source of protein consists in the higher fungi including the common oyster mushroom (Pleurotus ostreatus). It is known that fungal proteins having a rich amino acid composition are absorbed at the level of plant proteins, since they are “packed” in the intercellular chitinous membrane. Various technological methods are used in the processing of raw fungi materials in order to destroy the membrane and release the protein macromolecule. These include traditional processing methods, such as grinding, thermal exposure, etc. In the present article, electromagnetic sterilisation of convenience foods is considered as a means of improving product safety. The authors studied the effect of ionising electron radiation on the physicochemical properties of mushroom products using the example of a heat-treated, vacuum-packaged, semi-finished oyster mushroom product. The applied radiation doses were 1, 3, 6 and 9 kGy. The obtained data showed that, when a semi-finished product is irradiated with a dose of 1 to 6 kGy, a greater amount of protein is released compared to unirradiated samples; moreover, that the content of a number of essential amino acids also increases. Therefore, this method allows the biological activity of the nutrients to be increased. The sterilising effect of ionising radiation was achieved with a dose of 6 kGy due to slowing the growth of microorganisms: no pathogenic microorganisms were detected and no growth was observed over a period of 21 days. Thus, electronic ionising radiation as part of the technological process of processing mushrooms allows the biological value of the protein to be increased, preventing the growth of microorganisms and thereby extending the shelf life of mushroom products.