Black pepper (Piper nigrum L.) is a tropical crop with extensive medicinal potential in ethnomedicine and nutraceutical applications. The essential oil of black pepper finds wide applications in inhabitation of respiratory infections and soothing of muscular pains due to its warming and energizing property. The pungent bioactive piperine is responsible for this function, and therefore, efficient technology is required for an optimal extraction process of this compound. In the present article, we have developed a procedure for extracting black pepper essential oil from Vietnam, optimizing conditions that affect the extraction process. The effect of process parameters, namely material size, preservation method, the concentration of sodium chloride, the concentration of soak time, the ratio of material to water, temperature extraction, time extraction on the extraction yield, and relative efficiency were investigated. Results demonstrated that 20 g of black pepper milled with a mesh size of 160 obtained 0.48 g of essential oil (2.4%) at a raw material to water ratio of 1/21 (g/mL) at 150 °C in a time of 5.2 h. GC-MS (Gas chromatography–mass spectrometry) spectra showed that 3-carene (29.21%), D-limonene (20.94%), caryophyllene (15.05%), and β-pinene (9.77%) were present as major components. These results suggested that the essential oil extracted from Vietnamese black pepper is applicable in the manufacturing processes of insecticides and air deodorizers.

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Cashew apple (Anacardium occidentale) is considered as a by-product of the cashew processing industry. Efficient utilization of this material source contributes to valorization of cashew and reduces the burden of agricultural waste placed on the environment. This study investigated the effects of various blanching conditions on the total tannins, the ascorbic content and the phenolic contents of cashew apples. The three parameters including blanching temperature, blanching duration and salt concentration of the blanching solution were considered. It was found that optimal blanching conditions (heating at 70°C, NaCl concentration at 1% within 2 mins) resulted in cashew apples with vitamin C content and tannin retention rate of about 78.125% and 45% compared to those of the fresh samples, respectively. The cashew apple texture seemed to be insensitive to the heating process, however, the colors (mainly red gamuts of carotenoids) were lost during blanching.

Abstract-Square-wave stripping voltammetry at a carbon paste electrode was used to develop a method to measure silver ions at concentrations as low as 0.2 g/L in surface waters. Sample matrix was found to be an important factor affecting the measurement results. Because of these matrix effects, the peak shape of the voltammograms varied, and multiple stripping peaks for silver were observed. Total charge provided a more reliable measure of deposited silver than did peak height. The precision of the method for the analysis of standard reference materials containing silver was estimated to be 7.2% relative SD at 1 SD using a 95% confidence interval of the individuals. A full factorial experiment was performed to determine how the following factors affected measurement variability: electrode, renewal of the carbon paste electrode surface, silver ion concentration, preparation of standards and samples, and day-to-day variability. Samples of lake and river water were collected and analyzed for silver ion. In all samples the measured concentration of silver ion was Ͻ0.2 g/L, whereas the concentration of total silver was typically Ͼ0.5 g/L. Spiking experiments showed that the constituents of the river water samples had a greater ability to bind (remove) silver ion than did the lake water.