| Abstract [eng] |
The aim of this work is to analyze the scientific literature related to berries, its pomace and their application to food, and to evaluate the chemical composition and use of defatted lingonberry, raspberry and cranberry pomace as well as lingonberry extract in the development of functional bread and yogurt dessert products. The composition of lingonberry, raspberry and cranberry pomace (defatted using supercritical CO2) was analyzed to determine the possible effects on food. Methods for the determination of 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) radical-cation (ABTS●+) and the determination of oxygen radical absorption capacity (ORAC) were used to determine antioxidant activity. The total content of phenolic compounds (TPC) was determined using the Folin-Ciocalteu method. The antioxidant activity of the solid samples was measured using the QUENCHER method. Maximum antioxidant activity (ABTS●+ - 227,97 ± 11,87 mg TE/g, ORAC – 79,08 ± 5,39 mg TE/g,) and phenolic compounds content (28,45 ± 5,13 GAE/g ) found in lingonberry pomace. In terms of dietary fiber content, most of the dietary fiber was found in raspberry pomace. After the particle size measurements, the smallest particles by volume were characterized in cranberry pomace (207,34 ± 5,37 μm). To evaluate the effect of berry pomace on bread, 5 % of the flour was replaced with lingonberry, raspberry and cranberry pomace. The results showed that raspberry pomace did not have a negative effect on the porosity of the bread, while lingonberry pomace addition reduced the porosity of the bread. The bread with cranberry pomace was unsuitable for research because the dough did not rise, hence the resulting pastry was of unacceptable quality. These changes may have been due to small pomace particles and high dietary fiber content in cranberry pomace. The addition of berry pomace increased the antioxidant activity of the bread compared to the control pastry. Bread with lingonberry pomace had the highest antioxidant activity and content of phenolic compounds. After preliminary sensory analysis, bread without berry pomace was the most acceptable, however breads with lingonberry and raspberry pomace were rated better in terms of color, aroma, and texture. Accelerated solvent extraction was used to obtain ethanolic lingonberry extract from defatted lingonberry pomace. The yield of extraction was 54,61%. The TPC found in lingonberry extract was 28,44 ± 0,91 mg GAE/g extract, antioxidant activity was 78,39 ± 3,19 mg TE/g extract (ABTS●+) and 229,38 ± 19,24 mg TE/g extract (ORAC). The content of proanthanyanidins – 220,27 ± 4,87 mg/g extract and anthocyanins – 119,79 ± 13,11 mg/100 g of extract was also determined. To determine the effect of lingonberry extract on yogurt desserts, two types of yogurt (natural and greek) and different amounts of extract (0 g, 1 g, 2 g) was used. After evaluating the color changes, it was found in both recipes, that by increasing the amount of extract, the yogurt dessert darkens and attains pink color. The yogurt dessert made with natural yogurt had a more intense color than with greek yogurt. Examining the effect of the extract on the pH value, it can be seen that increasing the amount of the extract decreases the pH, which in turn means that shelf life might be increased. The addition of the extract also improves the firmness and stickiness of the yogurt dessert, but reduces its elasticity. |
