Using the D/S ratio to determine the quality of premium grade Monthong durian for domestic and export markets

Abstract

Monthong durian (Durio zibethinus L.) is Thailand’s main durian variety for domestic and export markets, especially China. Nowadays, the area for growing Monthong durian has increased around Cambodia, Laos, Myanmar, and Vietnam (CLMV), so competition for Monthong durian is challenged due to quality. The premium-grade Monthong durian quality was up on the flesh must have good taste, aroma, and mild (unpleasant odor). The ratio of dry matter (%D) and sulfur contents (%S) as the D/S ratio of unripe Monthong durian aril was employed to determine the quality of premium-grade Monthong durian for domestic and export markets, conducted at Chanthaburi and Nonthaburi province Thailand. Moreover, the effects of potassium sulfate and potassium chloride fertilizer application at one month before harvest on the quality and volatile compounds of the aril were compared. The results showed that KCl application in durian tree had a higher ester compound (ethyl 2-methyl butyrate) than K₂SO₄ application, while sulfur-containing compound (ethanethiol) was lower than that of K₂SO₄ treatment. As for effect on durian pulp quality, the K₂SO₄ treatment had a higher lightness and color angle in ripe durian pulp than in the KCl treatment. The texture of durian pulp was not significantly different in terms of hardness, adhesive force, and adhesiveness with both KCl and K₂SO₄ treatment. The D/S ratio was highly correlated with the sulfur content in unripe durian pulp and showed the tendency of the ratio to increase when the sulfur in the durian pulp decreased. The recommended D/S ratio for premium Monthong durian must exceed 316 units. The D/S ratio for premium quality Monthong durian at 32%DM is recommended to have a sulfur content below 0.1010%, and this value can be increased as durian dry matter increases. However, the D/S ratio must be above 316 units.