Uticaj zamesa i termičke obrade na antioksidativnu aktivnost pšeničnog brašna sa dodatkom brašna pečurke Boletus edulis
Stojanović, Jelena S.
Faculty:University of Niš, Faculty of Technology, Leskovac
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- Natural products of plants and lichens: isolation, identification, biological activity and application (MPNTR-ON 172047)
Numerous studies have shown that mushrooms are a source of biologically active compounds, such as polyphenols, which have antifungal, antibacterial, antioxidant and antiviral effect. Porcini (Boletus edulis) is one of the best quality mushroom because it is rich in protein whose composition is similar to the composition of animal origin protein, an excellent source of fibres, vitamins, minerals and polysaccharide. As porcini does not contain starch and sucrose, it is especially recommended for diabetics. Modern diet is mailny based on the use of food based on wheat flour, and baking industry has offered to consumers in the second half of the 20th century products named "healthy food" obtained from wheat flour with the addition of other kinds of flour which contain components that have a positive effect on human health. Starting with the assumption that the addition of porcini flour can improve the nutritional and physiological value of wheat flour, in dissertation, the content
of the ingredients essential for nutritional and energy value of porcini flour was determined, and the rheological properties of dough were tested. Acylglycerols, and fatty acids content, the content of the free and bound polyphenols in the mixture of wheat and porcini flour and their antioxidant activity were also determined. The separate part of the dissertation consists of the examination of the effect of mixing and thermal processing of dough from a mixture of wheat and porcini on the antioxidant activity, as well as on the content of some phenolic acids. A porcini mushroom from the eco-regions Piskupovo - Leskovac was used in the examination, and the flour was obtained by drying fresh mushrooms and subsequent grinding and sieving. The solid-liquid extraction for extracting the free polyphenols, and a method of alkaline hydrolysis for isolating bound polyphenols was used. Rheological properties of dough were determined by the methods of determining the quality of flour by farinograph and extensograph and amylograph, while a polyphenol content and antioxidant activity of extracts were determined by corresponding spectrophoto-metric methods. GC-MS method was used for determination of the fatty acids composition, and HPLC for determinationofthe content of individual acylglycerols and specific phenolic acids. The product obtained from the mixture of wheat and porcini flour was characterized by „ratio of thermal processing“, loss of mass and volume increase after thermal processing. The results show that the addition of porcini flour is a good way to increase both the nutritional value and the antioxidant activity of wheat flour, as a flour mixture have a higher content of protein, lipid, ash, cellulose, tannin, free fatty acids, mono-acylglycerols, total unsaturated fatty acids, content of minerals (Mg, Na, K and Fe) and the content of total polyphenols, and the extracts of free and related polyphenols from porcini flour have significantly higher anti-oxidant activity compared to the wheat flour. After dough mixing and thermal processing, the content of free polyphenols is higher than the content in a mixture of flour, and 87% of the total content of detected phenolic acids remains retained. The product obtained from a mixture of wheat and porcini flour by described recipe have the higher content of total polyphenols, a better antioxidant activity, a smaller mass loss during thermal processing and a higher volume, compared to product made only from wheat flour. In order to obtain food products with satisfactory rheological properties which are simultaneously enriched by porcini ingredients, it is recommended that the flour mixture contains 10-15% of the porcini flour.View More
Keywords:vrganj; porcini; polyphenols; antioxidant activity; phenolic acids; dough; mixing; thermal processing; polifenoli; antioksidativna aktivnost; fenolne kiseline; testo; zames; termička obrada