BY-PRODUCTS OF PLANT PROCESSING AND THEIR POSSIBLE APPLICATION INTO INNOVATIVE GLUTEN-FREE FOODSTUFFS

Abstract

Fruit and vegetable waste represent a significant source of nutrients, such as polyphenols, minerals, fibre etc. For the food industry, they make a huge contribution from an economic point of view. In our work, we observed the by-products of plant processing as possible local sources of biologically active componets for the further application in gluten-free products. The total polyphenols, antioxidant activity and crude protein in eight samples of plant by-products (apple, buckwheat, tomato, chilli and grape varieties of Irsai Oliver, Red Traminer, Alibernet, Cabernet) were determined. The crude protein content ranged from 1.4 % in buckwheat pomace to 15 % in chilli pomace. The highest polyphenol content was found to be in Alibernet grape pomace (256.9 mg.kg-1) and the lowest in chilli (155.15 mg.kg-1) pomace. The antioxidant activity of pomace ranged from 535.2 to 1359.49 mg.dm-3. Gluten-free products such as muffins and knäckebrots were designed, into which by-products were applied in the amount of 3%, except for chilli (0.5% addition). Developed gluten-free products were evaluated by sensory and texture methods. As the sample with the highest sensory quality were concluded to be muffins made with 3 % addition of Cabernet pomace. Grape and apple pomace can be recommended in gluten- free muffin production and tomato pomace in gluten free knäckebrot production.