| Abstract [eng] |
Presently, a strong focus is given on the development of vegetable protein production technology, and grain legumes are among the most popular plants grown under the local conditions which can be used for development of new food additives and/or products. However, their processing requires development of both efficient technological solutions for extraction of protein material and biological means for minimisation of antinutritional factors as well as improvement of functional properties. The goal of the study is the development of bean processing technology, including processes for extraction of protein fractions and biotechnological means which would allow reduction of antinutritional factors in the raw plant material as well as improvement of functional properties of products; organization of non-waste processing of beans using the biorefinery concept, evaluation of the possibility of using bean shells for production of lactic acid. It was found that air classification was a viable processing technology for obtaining bean meal fractions richer in protein: following air classification, the protein content in bean meal was 3.6 % higher in comparison with raw beans (unprocessed). During solid state fermentation by lactic acid bacteria (SSF LAB), a decrease (15 %) of the content of water soluble proteins was measured following 72 h of fermentation in water, compared to unfermented bean meal. SSF LAB had the greatest impact on bean proteins of low molecular mass, whereas protease processing influenced fractions of high molecular mass materials. In order to improve the functional properties of bean meal and bean proteins, such as the capacity of bean protein emulsion production, it was important to select an optimum duration of SSF LAB as well as processing of raw material with other enzymes, which was respectively 24 h and 30 min, since a decrease (2,8 %) of protein emulsion production capacity was observed after 72 h of SSF. In addition, SSF LAB can be used for reduction of antinutritional factors of beans: after 72 h of fermentation, the activity of protease inhibitors in bean meal decreased by 9,5 %, and digestibility of bean meal after fermentation increased by 5 %. It was found that ultrasound was an efficient method for reduction of microbial pollution of raw plant material (before LAB fermentation): following 60 min of ultrasound processing, the total bacterial count halved. In order to carry out non-waste processing of beans, the shell-rich fraction can be used for production of lactic acid. In order to increase the yield of lactic acid (39 %), it is recommended to treat bean shells (before LAB fermentation) with enzymatic preparation, which consists of cellulases, xylanases and β – glucanases. In summary, the tested bean processing technological solutions (air separation, ultrasound processing) in combination with biological means allow obtaining protein rich bean fractions to reduce bacterial pollution of raw plant materials and antinutritional factors as well as enhance the functional properties of protein rich fractions of beans. Solid state fermentation with use of selected lactic acid bacteria would allow for the development of new bean products and expand the range of their application in food industry. |
