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.
