Effect of elevated temperature storage on stability of pink guava juice added with melastoma malabathricum fruit

Abstract

This study focus on the stability of natural pigment from Melastoma malabathricum fruit in pink guava juice at 30°C and 60°C storage temperature. Analysis on the content of vitamin C, total phenolic content, lycopene, anthocyanin and color were conducted for 30 days. In general, the results showed higher reduction in all quality parameters at higher storage temperature. Freshly made PGJ contains 86.55±5.18 mg/100mL of vitamin C, 5.36±0.27 mg/L of lycopene, 933.50± 60.11 mgGAE/L of total phenolic content (TPC) and 1.36±0.32 mg/L of total monomeric anthocyanin. At day 30 of storage, vitamin C was reduced to 56.4% and 9.4% at 30°C and 60°C respectively. Total monomeric anthocyanins content was reduced to 38.2% and 7.2% at 30°C and 60°C respectively. Total phenolic content remained at day 30 was 12.1% and 7.5% at 30°C and 60°C respectively. While lycopene was found to be least affected by storage temperature compared to other quality attributes analyzed. The total color difference was increased drastically at 60°C between days 0 to 5 while linear increase was observed at 30°C storage. These studies provide useful information on the availability of the health beneficial compounds in fruit juice as well as their stability as natural food colourant during storage.