Phytochemicals, nutritional, antioxidant activity, and sensory analyses of Moringa oleifera Lam. collected from mid-hill region of Nepal.

This study was aimed to determine the phytochemicals and nutritional compositions, antioxidant activity and sensorial properties of Moringa oleifera extracts. The powders prepared from leaves and pods were mixed separately at the ratios of 1:0, 0:1, 0.25:0.75, 0.5:0.5 and 0.75:0.25 and labelled as mixtures A, B, C, D and E, respectively. Mixture A exhibited highest chlorophylls, tannins, phenolics and flavonoids contents (17.8 mg/g, 9.1 mg GAE/g, 91.1 mg GAE/g and 38.1 mg QE/g, respectively). The crude proteins content was higher (18.03%) in mixture A. The fats, fibres and carbohydrates amounts were higher (2.96%, 11.02% and 67.86%, respectively) in mixture B. The highest energy value (335.62 Kcal/100 g) and the highest antioxidant activity (83.2%) were in mixture A. However, most of the sensory attributes were ranked high for mixture D, signifying to use the equal proportion of leaves and pods powder of M. oleifera for the development of food products.

Ground water quality in the Kathmandu valley of Nepal.

A study was undertaken to assess the quality of groundwaters in the Kathmandu Valley, Nepal. The groundwater samples were randomly collected from shallow well, tube well, and deep-tube wells located at different places of Kathmandu, Lalitpur, and Bhaktapur districts in the Kathmandu valley. Physical, chemical, and microbiological parameters of the samples were evaluated to estimate the groundwater quality for drinking water. It was found that the groundwater in the valley is vulnerable to drink due to presence of iron and coliform bacteria. Iron was estimated to be much higher then the acceptable limit of World Health Organization (WHO) drinking-water quality guidelines (1.9 mg/L). Total coliform bacteria enumerated in groundwaters significantly exceeded the drinking-water quality standard and observed maximum coliform (267 CFU/100 mL) in shallow wells. The electrical conductivity and turbidity were found to be 875 µS/cm and 55 NTU, respectively, which are above the WHO recommendations for drinking water guidelines. However, pH value was measured within the acceptable limit. Arsenic, chloride, fluoride, and hardness concentrations were found to be in agreement with the recommendations of WHO drinking-water quality guidelines.

Carboxymethylation of corn starch and characterization using asymmetrical flow field-flow fractionation coupled with multiangle light scattering.

Asymmetrical flow field-flow fractionation (AsFlFFF) was coupled online with multiangle light scattering (MALS) to study the changes in the molecular weight and the size distribution of the corn starch during carboxymethylation. A corn starch was derivatized with sodium chloroacetate in alcoholic medium under alkaline condition to produce carboxymethyl starches (CMS) having various degrees of substitution (DS). The change in thermal characteristics and granule structure of the native corn starch and CMS were compared using Thermogravimetric analysis and scanning electron microscope. The ionic strength of the carrier liquid (water with 0.02% NaN(3)) was optimized by adding 50mM NaNO(3) to minimize the interactions among the starch molecules and between the starch molecules and the AsFlFFF membrane. A field-programmed AsFlFFF allowed determination of the molecular weight distribution (MWD) of starches within about 25min. It was found that carboxymethylation of starch results in reduction in the molecular weight due to molecular degradation by the alkaline treatment. The weight-average molecular weight (M(w)) was reduced down to about 4.4x10(5) from about 7.2x10(6) when DS was 0.14. It seems AsFlFFF coupled with MALS (AsFlFFF/MALS) is a useful tool for monitoring the changes taking place in the molecular weight and the size of starch during derivatization.