The Physicochemical and Antioxidant Properties of Pomelo (Citrus grandis Osbeck) Extract from Three Thai Cultivars

Pomelo (Citrus grandis Osbeck or Citrus maxima) is the largest citrus fruit, which is commonly consumed in Asian countries. The pulp is available in red, pink and white colors, composed of large, spindle-shaped extract sacs. Pomelo extracts have a sharp taste and flavor, which contains high levels of vitamin C and citric acid.

Determining physical properties, phytochemical content including phenolics, flavonoids and tannins; to evaluate antioxidant activity among pomelo extracts from Kao Yai, Thong Dee and Siam Ruby cultivars, which were the members of the white, pink and red groups, respectively.

The pomelo extracts were varied in color and turbidity. The odor and taste of them were citrus aromatic with a sour-sweet taste. The pomelo extracts from the Siam Ruby cultivar was the highest pH (4.01±0.3). However, Kao Yai pomelo extracts had the highest sweetness (°Brix = 0.5772%). The viscosity of pomelo extracts from Thong Dee cultivar was the highest and may contain high fibers and pectin. The color of Siam Ruby pomelo extracts was the most attractive color, while Kao Yai pomelo extracts were the tastiest. Total phenolic content (TPC), total flavonoid content (TFC) and tannin content (TC) were significantly different (p<0.05). Thong Dee pomelo extracts contained the highest TPC (45.74±8.12 mg GAE/100 ml) and TC (4.52±0.28 mg TAE/100 ml), while Siam Ruby pomelo extracts were the highest TFC (35.06±3.87 mg RE/100 ml). However, the DPPH scavenging capacities of the three pomelos extracts were not significantly different.