Modeling and Designing the Composition and Properties of Products Using Extracts of Grape Stems

This study aimed to investigate the modeling and design of product compositions using grape stem extracts, with an emphasis on phenolic compounds and antioxidant activity. Grape stems, a significant byproduct of winemaking, are a rich source of bioactive phenolic substances.

Aqueous ethanol extracts were obtained from grape stems of European varieties; the Magarach Institute developed a new selection. Phenolic compounds were quantified using ultraviolet-visible spectrophotometry via the Folin-Ciocalteu method and high-performance liquid chromatography (HPLC). Antioxidant activity was evaluated using an amperometric method. In addition, mathematical models have been developed to predict product composition based on mixing various components. Key HPLC parameters (detection wavelength, flow rate, column temperature, injection volume) and amperometric calibration procedures are described.

The mass concentration of phenolic substances in the extracts ranged from 7.95 to 16.40 g/dm³, and the antioxidant activity ranged from 6.30 to 13.90 g/dm³. Identifying the compositions of stem extracts was conducted with a focus on studying substances with a non-flavonoid structure: phenolic acids, esters, and stilbenes. Statistical analysis (analysis of variance (ANOVA) with post-hoc t-tests) confirmed significant differences (p < 0.05) between grape varieties. Furthermore, the developed mathematical model-validated using coefficient of determination (R²) and Root Mean Squared Error (RMSE) metrics-demonstrated robust predictive capabilities for product compositions.

These results indicate that grape stems are a valuable source of bioactive compounds for developing functional products. In addition, the proposed mathematical modeling approach offers a reliable method for designing product compositions. These findings provide a basis for developing software tools to optimize product formulation in the food industry.