‘Kampuchea’ guavas were treated with 300, 600 and 900 nL L‾¹ 1-methylcyclopropene (1-MCP) for 0,
3 and 6 h, and stored at 27˚C with 70% relative humidity. The C* values, soluble solids concentration, titratable acidity and pH of these fruits were not affected by both the 1-MCP concentrations and exposure duration while h˚ values and flesh firmness were affected by these treatments. The L* values, vitamin C content and weight loss were affected by the concentrations of 1-MCP, but not by the exposure duration. Less weight loss and disease incidence in fruit treated with 600 and 900 nL L-1 1-MCP. Fruit exposed to 6 h 1-MCP showed lowest disease incidence compared to other exposure duration in 5 days of storage. Treating Kampuchea guava fruit with 600 nL L‾¹ 1-MCP and exposure duration of 6 h was able to retain fruit colour, flesh firmness and delayed disease development for 5 days.
Red-fleshed pitaya fruit is a potential fruit for betacyanins extraction. However, there is lack of report on profiles and total contents of betacyanins in the peel and flesh. The objectives of this study were to determine colour, total betacyanins content and its separation in the peel and flesh of red-fleshed pitaya fruit harvested at 25, 30 and 35 days after flower anthesis (DAA) and to examine the usefulness of tristimulus colour measurement as predictors of pigment content in red-fleshed pitaya fruits. There were significant relationships between DAA and colour (L*, C* and h° values), and total betacyanins contents of peel and flesh of red-fleshed pitaya fruit. A total of three types betacyanins were separated from peel and flesh of pitaya fruit at 30 and 35 DAA while for 25 DAA, only one type of betacyanins was separated. The total concentration of betacyanins in the fruit peel of 25, 30 and 35 DAA was 0.24, 3.99 and 8.72 mg/mL, respectively. The fruit flesh contains 2.40, 7.93 and 11.70 mg/mL betacyanins at 25, 30 and 35 DAA, respectively, which was higher than peel. The tristimulus measurements can be adequately used to estimate the total betacyanins content of peel and flesh of red-fleshed pitaya fruit instead of tedious pigment extraction methods.