Recent applications of bio-engineering principles to modulate the functionality of proteins in food systems

Using casein and gluten protein fractions to obtain functional ingredients

Today, the food industry widely uses both animal and plant proteins. Animal proteins have a balanced amino acid composition, while plant proteins have more pronounced functional properties. However, both types of proteins can act as allergens, which limits their practical application. Therefore, we aimed to select optimal conditions for obtaining hypoallergenic mixtures based on casein hydrolysates and gluten proteins, which have good functional properties and a balanced amino acid composition. We used wheat flour (Makfa, Russia) with 12.6% of crude protein and 69.4% of starch, as well as rennet casein (Atletic Food, Russia) with 90% of protein. The methods included the Lowry method, the Anson method, Laemmli electrophoresis, ion-exchange chromatography, and the enzyme-linked immunosorbent assay. Protex 6L was an optimal enzyme preparation for the hydrolysis of gliadin, while chymotrypsin was optimal for the hydrolysis of glutenin and casein. The optimal amount for all the enzymes was 40 units/g of substrate. We analyzed the effect of casein, glutenin, and gliadin enzymolysis time on the functional properties of the hydrolysates and found that the latter had relatively low water- and fat-holding capacities. The highest foaming capacity was observed in gliadin hydrolysates, while the highest emulsifying capacity was registered in casein and glutenin hydrolysates. Further, protein enzymolysis significantly decreased allergenicity, so the hydrolysates can be used to obtain functional additives for hypoallergenic products. Finally, the mixtures of casein hydrolysate and gliadin or glutenin hydrolysates had a balanced amino acid composition and a high amino acid score. Also, they retained high emulsifying and foaming capacities. The study proved the need for mixtures based on wheat protein and casein hydrolysates, which have good functional properties and hypoallergenicity.

The Source of Protein or Its Value? Consumer Perception Regarding the Importance of Meat(-like) Product Attributes

Food product attributes may significantly influence the general perception of the product itself, as well as the willingness for its consumption. Assessment of the product is based on customers’ beliefs and individual preferences. Because meat-like products are presented as meat substitutes providing sufficient protein values, the present study aimed to determine the effect of protein source and labelling pointing at high protein content on the evaluation of the product. The experimental online study was conducted with a group of 552 respondents. Four versions of product packaging were designed and tested. These packages differed in the presence or absence of the Nutrition Claim and the presence of the text indicating the vegetable or meat origin of the product. Data collected in the experiment were analyzed using a 2 × 2 ANOVA. The study revealed that the source of protein (plant vs. animal) appears to shape consumers’ perception of the product as more eco-friendly (F (1.518) = 38.681, p < 0.001, η2 = 0.069), natural (F (1.518) = 15.518, p < 0.001, η2 = 0.029), and healthy (F (1.518) = 25.761, p < 0.001, η2 = 0.047). Moreover, labelling including a “high-protein” Nutrition Claim increases the willingness to consume the product (F (1.518) = 4.531, p = 0.034, η2 = 0.009), and provides the impression of it being more eco-friendly (F (1.518) = 6.658, p = 0.01, η2 = 0.012) and of a higher quality (F (1.518) = 7.227, p = 0.007, η2 = 0.014). The obtained results may have theoretical significance by improving the understanding of factors determining the perception of food products and the use of meat substitutes.