Effect of Leaf Extract from Lycium barbarum on Preservation of Cherry Tomato Fruit

Abstract

The preservation of cherry tomatoes is a challenge for farmers, sellers, and processors. In recent years, natural extracts of plants have been increasingly used for the preservation of fruits and vegetables. In this study, we investigated the effect of treatment with goji berry (Lycium barbarum) leaf extract on the postharvest freshness of cherry tomatoes, and we determined the active ingredients, antioxidant capacity, and antifungal activity of the extract. Goji leaf extracts were tested at different concentrations (0.2–1.0 g/L) to assess their effects on preserving the freshness of cherry tomatoes at 5 °C and 20 °C. The goji berry leaf extract was rich in polysaccharides, saponins, polyphenols, and other active ingredients (1.11–45.83 mg/g), and the antioxidant capacity and antifungal activity were outstanding. Treatments with 0.2, 0.4, and 0.6 g/L of goji berry leaf extract at 20 °C helped to preserve tomato fruit, where 0.4 g/L was the most effective, followed by 0.2 and 0.6 g/L. However, 0.8 and 1.0 g/L had no effect. Treatment with 1.0 g/L of goji berry leaf extract at 5 °C effectively reduced the loss of quality of tomato fruit. This treatment maintained the firmness and color of the tomatoes and maintained the levels of nutrients such as vitamin C, total acids, and total soluble solids. The next most effective doses were 0.8 g/L and 0.6 g/L. Cherry tomatoes treated with goji berry leaf extract could be stored for 21 days at 20 °C and for 35 days at 5 °C. Compared with the control groups treated with distilled water and no treatment, the storage period was extended by 3–6 days at 20 °C and by 7–14 days at 5 °C. The results obtained in this study provide a theoretical basis for extending the storage period of cherry tomatoes using goji berry leaf extract and the development of natural preservatives as well as enhancing the utilization of germplasm resources.