Obtaining Analogues of Fermented Milk Products from Seed Meal Using New Strains of Lactic Acid Bacteria

Abstract

A method has been developed for producing analogs of fermented milk drinks from pumpkin seed meal, which is a massive waste product from oilseed production, using new strains of lactic acid bacteria (LAB) isolated from different samples of kumiss. Based on the results of screening 50 LAB isolates capable of fermenting milk and aqueous meal extracts in a wide pH range, three strains with the best growth characteristics were selected. These strains were identified as representatives of the genus Lacticaseibacillus, most closely related to L. rhamnosus and L. casei (with 99.93 and 99.65% similarity in 16S rRNA gene sequences). An optimal scheme for producing drinks has been selected, including grinding meal, optimized extraction with alkaline solutions, heat treatment of the extract to remove foreign microflora, introduction of the inoculum (3–5% vol/vol) of new LAB strains, and fermentation at 37^oС for ten hours. Compared with the fermented milk product obtained by fermenting milk with the same microorganisms, the drink made from meal extracts was distinguished by the absence of lactose and cholesterol, and increased content of unsaturated fatty acids (2.3 times) and protein (1.7 times), and the presence of essential amino acids in proteins. Thus, pumpkin seed meal, which is still used ineffectively, is a good basis for obtaining analogs of fermented milk products with beneficial properties. The developed method for producing lacto-fermented drinks can be adapted for processing other types of meals and cakes.