Enhancing shelf-life in tomato (Solanum lycopersicum) using sustainable seaweed-based coatings

Abstract

Preservation is essential for perishables, but the harmful effects of chemical preservatives on health and the environment highlight the need for sustainable alternatives. Seaweed-based coating offers an effective, safe and cost-efficient solution to these challenges. This study aimed to enhance the shelf life of tomatoes using red seaweed-based coatings. Red seaweeds (Gracilaria verrucosa and Chondrus crispus) were collected and hot water extracts were prepared by extracting 1 g of dried seaweed in 100 mL of water at 80 °C for 3 hours. The antioxidant activity and viscosity of the seaweed extracts were measured, and two total sugar-concentrated solutions (0.05% and 0.1%) were prepared to dip tomatoes for 15 min. Both coated and uncoated tomatoes were stored at room temperature and at 15°C for 32 days. Weight loss, color, firmness, juice percentage, total soluble solids (TSS), total acidity and TSS to acidity ratio were determined at 6 day intervals. Data were analysed using a 3-factor factorial completely randomized design with two temperatures, two concentrations, and two seaweed varieties, each with three replicates. Results show that the antioxidant activities of C. crispus and G. verrucosa extract were 44.87% and 20.83% respectively. Tomatoes coated with 0.1% C. crispus and stored at 15°C for 32 days showed significantly reduced weight loss (3.01 g), along with increased firmness (10.7 N), juice percentage (57.94%) and titratable acidity (0.352 %), while showing reduced TSS (9 ◦ Brix) and TSS/acid ratio (24.6) compared to uncoated tomatoes stored under the same conditions. Higher concentration seaweed-based coatings extend tomato shelf lifeby preventing deterioration and preserving quality, especially when stored at 15°C compared to room temperature. These findings reveal the potential of seaweed-based edible coatings as an eco-friendly postharvest technology for enhancing shelf-life and maintaining the quality of tomatoes under different storage conditions.