Antioxidant Properties of Functionalized Tomato Sauce and Leather

Abstract

As global concern about health, sustainability and food security grow, valorizing food byproducts has become an essential strategy in functional food development. In this context, this study aimed to develop and evaluate functional tomato-based product (tomato leather and tomato sauce) by incorporating tomato byproducts with key mediterranean ingredients such as olive powder, pea protein and aromatic herbs. The tomato byproducts were processed into powdered form and incorporated into new formulations of tomato leather and sauce. In this study, Soxhlet extraction was used to measure total phenolic content (TPC) and antioxidant activity assessments were conducted using the Folin-Ciocalteu (F-C) method and ABTS essay. Accelerated shelf-life analysis (high temperature- high humidity) over 12 weeks evaluated changes in antioxidant potential, color, pH, water activity, and microbial safety of the newly formulated tomato products. Statistical analysis assessed differences and antioxidant potential and product stability. Results showed that tomato seeds had the highest TPC (91.43 mg GAE/100 g), while the skin exhibited better antioxidant potential (31.45 μmol TE/g). The tomato leather, enriched with olive powder and spices, had higher TPC (210.1 mg GAE/100 g) and antioxidant activity (41.02 μmol TE/g) compared to the tomato sauce enriched with olive powder and tomato peel powder (142.79 mg GAE/100 g; 23.85 μmol TE/g). A strong correlation (Pearson's coefficient R = 0.953) between TPC and antioxidant potential was observed. Over 12 weeks, tomato leather maintained stable water activity and microbial load, though its pH decreased. Its antioxidant potential showed an overall increase, linked to color darkening due to Maillard reactions. Tomato sauce showed fluctuations in water activity and a slight decrease in pH, with antioxidant potential increased over time, correlated with color changes. The study demonstrates the potential of using tomato byproducts and Mediterranean ingredients to enhance both sustainability and nutritional value.