Abstrakt

Fruit pomace should not be considered as a waste product but as a by-product as it contains a lot of valuable components such as dietary fiber, bioactive compounds and a source of nutrients. The reasonable way to utilize these by-products, both fresh or dried, could be the fermentation of its extracts, leading to beverages with functional properties. In our research, we checked the possibility of using chokeberry, apple and blackcurrant pomace as a raw material for obtaining fermented fruit beverages. The starter culture was a tea fungus traditionally used to prepare tea kombucha. This consortium contains acetic bacteria and osmophilic yeast and sometimes lactic acid bacteria. Some functional properties of bacterial cellulose (BC) membrane have also been investigated. It was verified whether microorganisms perform metabolic processes in the fruit pomace extract based on pH and total acidity measurements. The antioxidant activity of beverages and BC was determined using spectrophotometric technique with ABTS and antimicrobial activity using agar diffusion method. Increase in total acidity of fruit pomace extracts and in antioxidant activity was observed in all beverages. The highest activity occurred in chokeberry and blackcurrant beverages. Cellulose membranes also demonstrated antioxidant activity, with the major one being that formed on chokeberry beverage. Both, beverages and BC, possessed antimicrobial properties. The chokeberry drink inhibited the growth of both gram-negative and gram-positive bacteria. In contrast, the apple beverage was only active against gram-negative bacteria. In the case of BC obtained from chokeberry beverage antimicrobial activity only against gram-negative bacteria was observed, while that from apple beverage against gram-positive and gram-negative bacteria.

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