Novel vegetable proteins, like those extracted from abundant raw materials (grass) or agri-food by-products and waste streams (oilseed meals), are expected to be used as replacers for animal-derived proteins, due to higher production efficiency, reduced life cycle environmental impact and possibility to meet consumers' dietary or cultural preferences. Although having a versatile functionality (emulsifying, foaming, gelling, texturizing agents), application of proteins is limited since their properties highly depend on their structure and composition, environmental factors (pH, ionic strength, presence of other micro-and macro-molecules in food matrices) and isolation method and conditions. The objective of this article is to review the current techniques used to isolate the proteins from vegetable raw materials and comment on the influence of extraction method and conditions (pH, ionic strength, extraction media temperature, extraction time, etc.) on protein properties (yield, purity, appearance, solubility, denaturation degree, emulsification efficiency, etc.). The utilization of novel technologies such as ultrasound assisted extraction, electro-activation technique and approaches (enzyme-assisted extraction) to improve protein extraction yield or functionality was also discussed.

Different types of instant porridges have become a popular choice for breakfast, and it is known that breakfast is an important meal for daily appetite control. On our market there is porridge of uniform composition based on cereals, primarily oats. However, high-protein porridge is not available, which is a significant deficiency in the assortment of these products. In addition, insufficient intake of quality protein remains a dietary problem, particularly among children and the elderly, where diets consist mainly of cereals. Plant proteins in combination with cereals could be used to produce high protein instant porridge. In this study, proteins from legumes such as soybean and pea, specifically soy protein concentrate, soy protein isolate, and pea protein isolate were applied. Protein preparations were added to the main mixture composed of the buckwheat and corn extrudate and other additional ingredients. The protein preparations were added at three different levels: soy protein concentrate at 0, 7.5 and 15% (w/w main mixture basis) and soy protein isolate and pea protein isolate at 0, 15 and 30% (w/w main mixture bases), with the objective of optimizing the composition of the high-protein instant porridge. The aim of optimization was to maximize the protein content and overall acceptability. The optimal doses of protein preparations were determined using the method of desirability function and it was found that the optimized dose for the soy protein concentrate was 1.43 g/100 g, soy protein isolate 21.07 g/100 g and pea protein isolate 14.83 g/100 g. The prediction value for protein content was 24.77 %/DM and overall acceptability 4.09. The obtained experimental values were close to the prediction values: 24.32 %/DM for protein content and 4.41 for overall acceptability. The protein content of the formulated porridge was 24.32 %/DM, which is more than twice as high as that in the oat porridge present on the market. Based on standard nutritional values, the newly formulated high-protein instant porridge could be recommended as appropriate breakfast meal for adults.