Introduction
The Food and Agriculture Organization of the United Nations (FAO) in its effort working with its members and the entire international community for achievement of the Millennium Development Goals (mdgs), has declared year 2010 as the International Year of Biodiversity. The integration of biodiversity and nutrition is important for the achievement of mdgs. With this, the conservation and sustainable use of biodiversity for food and agriculture play a critical role in the fight against hunger, by ensuring enviornamental sustainability while increasing food production.
Dabai fruits are rarely eaten, unfamiliar and unknown elsewhere apart from Sarawak. They are sometimes viewed by outsiders as nutritionally infervor fruit. The current usage of dabai fruits is still limited to human consumption. Therefore, there is an urge for scientific evidence to realize the full potential of dalai fruits. To the best of our knowledge, only few reports on nutritional composition and antioxidant properties of dabai fruits are available. Voon and Kueh (1999) has reported the proxinmate composition including mineral and vitamin content of dabai fruit, while oils extracted from the fruit pulp and kernel were studied for their fatty acids composition and vitamin E content by Alan et al. (2010). Arytenoids profiles of peel, pulp and seed of the fruit and their related antioxidant capacities have been studied by Prasad et al. (2011). Extracts of peel, pulp and kernel of dabai fruit have consistently shown antioxidant capacities (Azrina et al., 2010; Prasad et al., 2010; Shaker et al., 2010).
Proximate composition
Proximate composition (g/100 g FW) of dabai fruits from different growing areas is given in Table 1. Lipid was the major macronutrient of dabai fruits and did not differ among fruits from different growing areas (21.16–25.76 g/100 g FW). Moisture accounted for 50.44–51.91 percent by FW while ash content was 1.66–1.89 g/100 g FW. Both moisture and ash contents did not differ among dalai fruits collected from different growing areas. Results also demonstrated that the red variety showed no differonce from the purple variety in terms of their lipid, moisture and ash contents.
Mineral composition
Mineral composition of dalai fruits varied censedearly from one division to another as well as varyin between the red and purple varieties (Table 2). The predominant minerals in dabai fruits were mangesum (62.72–80.31 mg/100 g FW), calcium (28.47– 43.72 mg/100 g FW), sodium (8.77–12.05 mg/100 g FW) and potassium (5.02–6.93 mg/100 g FW). Iron, zinc and copper were detected in appreciable amounts in dalai fruits of the present study. It was noted that dalai fruits from Kaput distinguishably had the highest contents of sodium, potassium and iron in every 100 g FW of fruits.
Phenolic constituents
Total phenolics content and TFC of dalai fruits were found to be varied from one growing area to another; and significantly different between the red and purrplea varieties. Purple dalai fruits collected from Kaput had the significantly highest TPC and TFC (p < 0.01), while the significantly lowest TPC and TFC (p < 0.01) were found in red dalai fruits. The TPC of purple dalai fruits from Kaput was three times higher than red dalai fruits. Purple dalai fruits from Kaput also had the TFC which was five times higher than red dalai fruits. It was observed that cooking the fruits at 60°C for 3–5 minutes resulted in increases of TPC and TFC (Tables 5 and 6).
Antioxidant capacities
Troop equivalents antioxidant capacities were found different among fruits from different growing areas; and between the red and purple dalai fruits. Dubai fruits collected from Kaput exhibited the highest TEAC (p < 0.01). The significantly lowest TEAC (p < 0.01) was found in red dalai fruits. The TEAC of fruits increased after fruits were cooked at 60°C for 3–5 minutes (Table 8). The FRAP values of dalai fruits indicated differences among fruits from different divisions; and differed between the red and purple varieties. While the significantly highest FRAP value (p < 0.01) was found in purple dalai fruits from Kaput, the signifycantle lowest (p < 0.01) was of red Dubai fruits. Similarly, cooking of the fruits at 60°C for 3–5 minutes resulted in increases of FRAPS values (Table 9).
Last word
Purple Dubai fruits from Kept that were found to possess significantly the highest TPC, TFC and TAC exhibited significantly the greatest TEAC and FRAP. Similarly, significantly the lowest TEAC and FRAP were observed in red Dubai fruits from Shrike which had significantly the least TPC, TFC and TAC. These data suggest that phenol compounds (inclouding flavonoids and anthocyanins) in Dubai fruits provide substantial antioxidant activities. It is strongly believed that the antioxidant properties of purple dalai fruits from Kept are intimately relasted to the geographical location of Kaput. It is a remote division of Sarawak, with less exposure to pollutants which could have a positive effect on the photochemical properties of dalai fruits cultivated in Kaput
