Pomace from colored fruits as a source of bioactive ingredients

Juice production is a significant part of worldwide fruit processing. This involves the generation of high amounts of pomace. Although fruit pomace is a potentially rich source of bioactive components, its use for food purposes is only marginal. Due to the limited shelf life of fresh pomace, it may be considered expedient to obtain freeze-dried pomace. Lyophilized pomace has both a long shelf life and makes an attractive addition to desserts or baked goods.

The aim of this study was to determine the content of bioactive components in fresh and freeze-dried pomace obtained from kamchatka berry, black chokeberry, blackberry, and dark grape fruits. The efficiency of pomace obtention, dry matter content, total polyphenols content, and quantitative and qualitative anthocyanin composition were determined.

The fresh pomace contained from 21.5±0.1% (blue honeysuckle) to 27.5±0.1% dry weight (blackberry), and the values for the freeze-dried ones ranged from 97.4±0.1% (blue honeysuckle) to 97.9±0.1% d.w. (blackberry). The content of polyphenols and anthocyanins significantly depended on the type of raw material used. The total content of polyphenols ranged from 1379.7±11.0 (dark grapes) to 6303.6±86.1 mg/100 g d.w. (black chokeberry). After the freeze-drying process, the polyphenol content decreased by 4.3-19.2%. The studied pomace was also a rich source of anthocyanins, the content of which in fresh pomace ranged from 422.3±40.7 (dark grape) to 3626.9±12.9 mg/100 g d.w. (black chokeberry), and in freeze-dried pomace, these values did not change significantly and were 414.7±18.1 and 3743.5±65.2 mg/100 g d.w., respectively.

Pomace from colored fruits can be a valuable source of bioactive components and pigments. Particularly rich sources of polyphenols and anthocyanins are black chokeberry and kamchatka berry. Feeeze-dried pomace, in particular, is an interesting product for enriching foods in the studied components, as well as for food coloring.