| Abstrakt: |
Million tons of food is wasted annually in the EU, and one of the possibilities how to decrease it, is in transformation of food waste into products of commercial use. The aim of this work was to evaluate by-products (BP) of plant processing as a potential source of biologically valuable substances for its further utilization in food/feed processing. Several kinds of BP were tested: apple, buckwheat, grape (Alibernet, Cabernet, Irsai Oliver, Traminer red), chilli and tomato for their content of individual phenolic substances, fiber and nitrogen substances. After their drying and grinding, BP were analyzed and applied as the powder into the food products. Nitrogen substances were analyzed by Kjeldahl method, the crude fiber by the Hennenberg-Stohmann method and phenolic substances by high-performance liquid chromatography with diode-array detection (HPLC - DAD). Having in mind that BP can be an good source of selected nutrients for food/feed industry, we tested their application into gluten free food products such as corn bread and rice muffins in order to evaluate their sensory properties (sensory panel) and texture analysis (TA.XT Plus). Nitrogen substances ranged from 1.7% (buckwheat) to 15% (chilli), fiber from 11% (Tramin red) to 54.11% (buckwheat). High contents of resveratrol (up to 1781.01) were monitored in white varieties of grape BP. Irsai Oliver contained relatively high content of gallic acid (284.11 mg x kg-1), it was also present in Tramin BP (34.48 mg.kg-1). Another interesting component detected was rutin (116.21 mg x kg-1 in tomato BP), but also other phenolics were found. Model gluten free rice muffins with Cabernet grape BP (3%) and cornbread with apple BP (3%) were well evaluated by sensory panel, detected firmness of the products was comparable (1423 vs. 1339 g). We prepared very well accepted gluten free muffins based on rice flour and xylitol with Cabernet BP addition, showing an interesting violet color of products and supposing to have higher content of fiber, protein and phenolic substances as well corn bread with oligofructose and apple BP, both products without any synthetic food additive application that is common for all gluten free products. We can conclude that observed BP are still an excellent source of selected nutrients for food/feed industry. When speaking about BP application into gluten free food products such as corn bread and rice muffins, it is known that in patients with celiac disease, nutrient malabsorption is often observed and deficiencies in several nutrients is demonstrated. [ABSTRACT FROM AUTHOR] |
