The aim of this study is to comprehensively investigate the composition and properties of apple by-products, generated during the production of frips, as well as to assess its potential for use in various fields. To achieve this goal, modern chemical analysis methods were used, including chromatographic, spectroscopic, and microbiological methods, as well as chemical methods to determine the content of soluble and insoluble dietary fiber. The study focused on by-products generated during the processing of 18 apple varieties at an operating frips production facility in southern Russia. It was established that the quality of frips obtained from the studied apple varieties is determined by the ratio of protopectin to soluble pectin. A multifaceted analytical study revealed that the total dietary fiber content in the secondary apple raw material samples studied was 49.3–49.5% of dry matter, of which 13.6–13.8% was accounted for soluble fractions. The concentration of polyphenolic compounds, which are key antioxidants, reached 299.5–399.8 mg per 100 g of dry matter, indicating their significant presence and potential biological activity. It has been established that the prebiotic index of apple fiber is 1.8, which exceeds the threshold level of 1.0 and indicates its pronounced ability to stimulate the growth and metabolic activity of commensal microorganisms in the intestine.
Donchenko et al. (Thu,) studied this question.