Effects of High-Temperature Drying on the Flavor Components in Thai Fragrant Rice

The effects of high-temperature drying on Thai Jasmine rice were investigated. Paddy was first rewetted and then dried using a two-stage drying process, involving a fluidized bed at high temperature, followed by shade drying (ambient air drying). Three high drying temperatures: 100, 125, and 150°C were studied. Volatile compounds were extracted by distillation and extraction in a Likens and Nickerson apparatus, and analyzed by gas chromatography-mass spectrometry. A total of 94 volatile compounds were identified. These included 21 alcohols, 19 aldehydes, 14 ketones, 12 acids, 9 heterocyclic compounds, 8 hydrocarbons, 5 esters, and 6 miscellaneous compounds. 2-Acetyl-1-pyrroline, a major constituent of volatiles in fragrant rice was identified and tended to increase in concentration with increasing drying temperature. The three different drying temperatures used in the fluidized bed dryer were found to have an effect on the volatile components of Thai Jasmine rice. The increase in drying temperature contributed to the formation of new compounds, as well as the loss of other desirable volatiles.     

Effects of Drying Treatments on the Composition of Volatile Compounds in Dried Nectarines

The effects of drying treatments including dryer type, drying conditions, and sample preparation on the composition of volatile compounds in two cultivars of dried Australian nectarines were investigated in this study. A cabinet dryer, a tunnel dryer, and a heat pump dryer were evaluated. The sample preparation included halving or slicing the fruit to different slice thickness and in different directions. The volatile compounds in fresh and dried nectarines were isolated using Likens Nickerson simultaneous distillation and extraction technique and identified by gas chromatography. The results indicated that a heat pump dryer was the best system for preservation of volatile compounds in sliced dried fruit in terms of lactones and terpenoids followed by cabinet dryer and tunnel dryer.     

Effects of Drying Treatments on the Composition of Volatile Compounds in Dried Nectarines

The effects of drying treatments including dryer type, drying conditions, and sample preparation on the composition of volatile compounds in two cultivars of dried Australian nectarines were investigated in this study. A cabinet dryer, a tunnel dryer, and a heat pump dryer were evaluated. The sample preparation included halving or slicing the fruit to different slice thickness and in different directions. The volatile compounds in fresh and dried nectarines were isolated using Likens Nickerson simultaneous distillation and extraction technique and identified by gas chromatography. The results indicated that a heat pump dryer was the best system for preservation of volatile compounds in sliced dried fruit in terms of lactones and terpenoids followed by cabinet dryer and tunnel dryer.