Coconut is grown in tropical and subtropical areas worldwide. The endosperm (water and meat) is consumed and processed in different forms. This study investigated the antioxidant activities and identified the phenolic compounds existing in the water and meat of coconut fruits at three different maturity stages, i.e., 180, 190, and 225 days after pollination from two planting areas in Thailand. Total phenolic content and antioxidant activity indices increased as the coconut matured from 180 to 190 days after pollination and then decreased or remained unchanged at 225 days after pollination. Catechin and salicylic acid were the major phenolic compounds found in the water, while gallic, caffeic, salicylic, and p-coumaric acids were found in the meat. The fat content of the meat increased significantly with maturity stage. Medium chain fatty acids profiles were also analyzed. The results are important for producers, processors, and consumers to realize an optimal quality and functionality of coconut water and meat when used for specific purposes.
Dried turmeric is used as a spice and traditional medicine. The common drying methods for turmeric (Curcuma longa L.) are sun drying and solar drying. In this study, turmeric slices with a thickness of 2 mm were dried at 40, 50, 60, and 70 °C in a laboratory hot-air dryer with a simulated solar radiation applied through transparent polycarbonate cover (UV impermeable) and PMMA cover (UV permeable). Air velocity and relative humidity of drying air were fixed at 1.0 M·s−1 and 25 g H2O kg−1 dry air, respectively. Light significantly increased the sample temperature under both covers. Page was the best model to predict the drying characteristics of turmeric slices. Drying rate correlated with the effective moisture diffusivity, which increased at higher temperature. The hue angle (h°) of turmeric was distinctly lower at 70 °C under both covers. The dried products were of intensive orange color. Curcumin, demethoxycurcumin, and total curcuminoids were affected by the cumulated thermal load (CTL). The lowest curcumin content was found at 40 °C under PMMA (highest CTL). The optimum drying condition was 70 °C under polycarbonate cover due to shorter drying time and better preservation of color and curcuminoids in the dried product.