Determination of red colour and lycopene development of Platinum, Padma and Abhiman varieties of tomatoes stored at different temperatures and preparation of tomato puree with watermelon pulp

Lycopene is responsible for red colour development in tomatoes. Since locally grown tomatoes have less lycopene content, it negatively affects the production of tomato sauce at required quality.  The aim of this study was to determine the best post-harvest practices to improve the lycopene content in locally grown tomato (Solanum lycopersicon) varieties namely, Platinum, Abhiman, and Padma. They were harvested at the colour break stage and stored at room temperature (32 °C – 34 °C) and cold room temperature (22 °C) for 14 days. Thereafter, they were subjected to analysis, content and colour development (a*) and the obtained values were compared. Lycopene was extracted using a mixture of hexane, ethanol and acetone (2:1:1 ratio) and lycopene analyzed spectrophotometrically. Watermelon is rich in lycopene and pulp extracted from it was incorporated with tomato purees at different ratios to improve the red colour of tomato purees. Results revealed that the average lycopene content of ripe tomatoes at the harvesting stage ranged from 8.34 ± 1.91 to 9.32 ± 2.21 mg/100 g fresh weights.  Tomatoes stored at cold room temperatures contained significantly higher amounts of lycopene (37.05 ± 2.50 to 43.03 ± 1.52 mg/ 100 g fresh weight) compared to that of tomatoes stored at room temperatures (16.50 ± 3.10 to 19.04 ± 2.54 mg/100 g fresh weight). Results revealed that the incorporation of watermelon pulp did not contribute to elevating the colour of tomato puree, even at different ratios.