Improving the Storage Stability of Tomato Paste Enriched by Different Concentrations of Zinc Micronutrient

This study evaluates the fortification of tomato paste with zinc (Zn) micronutrient and its impact on quality control during storage. Industrial tomato paste was divided into four groups: a control group and three groups fortified with 20 ppm zinc (Zn-20 ppm), 40 ppm zinc (Zn-40 ppm), and 60 ppm zinc (Zn-60 ppm). The samples were stored at 4°C for 60 days, with physical tests: L*, a*, b*, ∆E, and a*/b*, chemical tests: pH, total soluble solids (TSS), lycopene, total phenol content (TPC), and antioxidant capacity (AC), and microbiological tests: acid-resistant mesophilic bacteria (ARMB) and mold and yeast (MY), assessed every 15 days. Additionally, the aroma properties of the paste were analyzed using an electronic nose system. The results demonstrated a decline in L*, a*, b*, and a*/b* indices and reductions in lycopene, TPC, and AC levels across all treatments during storage. In contrast, ∆E, ARMB, and MY counts increased over time. Lycopene, TPC, and AC exhibited the highest reductions in the control group by the end of storage, at 84.72%, 16.29%, and 38.69%, respectively, while the Zn-40 ppm group showed the minor decreases, with reductions of 70.85% for lycopene, 3.39% for TPC, and 22.86% for AC. Analysis of variance (ANOVA) indicated that the storage period, fortification levels, and their interactions had significant effects (p ≤ 0.01) on the properties of the tomato paste. The overall accuracy of quadratic discriminant analysis (QDA) in identifying and distinguishing samples across all storage periods was 100%, with no misclassifications among the 32 samples analyzed.