Changes in physicochemical properties of Gac fruit (Momordica cochinchinensis Spreng.) during storage

Abstract

Gac fruits were evaluated during storage to observe detailed changes in aril quality (lycopene, β-carotene and oil concentration). The relationships of these qualities with fruit firmness, skin colour and the total soluble solids (TSS) of aril were also explored to identify any potential indicators of aril quality. Mature fruit were manually picked and sorted for size from two field crops in Vietnam and a greenhouse crop in Australia. They were stored in plastic containers at ambient conditions until the fruit was considered unsalable (7 days at 30°C in Vietnam and 21 days at 21°C in Australia). Storage for a week generally improved aril quality in terms of increasing the concentrations of lycopene (up to 4.3 mg g-1 dry weight), β-carotene (up to 1.5 mg g-1 dry weight) and oil (up to 0.4 g g-1 dry weight) and these were strongly correlated with firmness (lycopene -0.923, β-carotene -0.754, oil -0.764, p < 0.01) and TSS (lycopene -0.747, β-carotene -0.664, oil -0.672, p < 0.01). However, quality declined with further storage. Skin colour did not relate well to aril quality but fruit firmness and aril TSS are candidates in the development of simple indices for the quality management of commercial Gac fruit.