Wheat bran proteins – raw material for production of nutritional-valued food

abstract

English

Wheat bran (WB) is a sustainable material produced by milling industry in very high quantities. It forms cover layers of wheat kernel, which are removed during wheat flour production. This secondary product contains many nutritional significant components, which could be utilized for the enhancing the food quality. The protein fraction is one of the most abundant components of wheat bran (13–18 %) and according to its nutritional characteristics, the inclusion to human diet seems to be convenient and required. The proteins are the part of lignocellulosic structure of WB. However, it could be easily isolated thanks to its ampholytic nature by pH-shift method. The protein fraction is extracted by NaOH solution (pH 10 ± 0,1; 2 h; room temperature) in ratio 1:20 with continuous mixing. The proteins were separated from deproteined WB by centrifugation (8000 rcf, 15 min, r.t.) and precipitated by pH adjustment to 4 ± 0,05 (1M citric acid). Precipitated proteins were isolated by centrifugation and dried by lyophilization. The quality proteins are nutritionally very significant commodity which is recommended to be a common part of a diet, especially for the athletes and the elderly. WBPI contains more than 80 % of proteins represented by several protein fractions (up to 170 kDa). As it is typical for plant proteins, the most abundant amino acid of WBPI is glutamic acid. However, there are also high concentrations of amino acids, which are helpful in muscle and wound regeneration, as arginine and proline. This protein isolate seems to be ‘complete’ according to the representation of all essential amino acid. The limiting amino acids of WBPI are phenylalanine and tyrosine. However, the determined 93% digestibility of this material provides the opportunity for utilization of WBPI in production of food with added nutritional value. As the part of this research, WBPI was used for production of several food commodities with added protein value, e. g. baguettes, yogurt, or bars. In all these products the protein content was increased by the addition of WBPI which made them high-protein food. However, during the production it was necessary to reflect the negative side effects of WBPI addition to different food matrices. The defects of products were evaluated by rheological (product fragility/rigidity) or sensory analysis (acidity/bitterness of WBPI) and eliminated by different approaches (change of recipe procedure, flavour masking, etc.).

Wheat bran, wheat bran proteins, high protein food

SLAVÍKOVÁ, Z.; POŘÍZKA, J.; DIVIŠ, P.

12. 10. 2023

International Ecological Engineering Society

ZHAW Life Sciences und Facility Management, Grüentalstrasse 14, 8820 Wädenswil, Switzerland