Detection of tricresyl phosphates and determination of tri-o-cresyl phosphate in edible oils

Tricresyl phosphate (TCP) in contaminated edible oils was extracted using acetonitrile and detected by thin layer chromatography as well as gas chromatography (GC). The chromatoplate was developed with isooctane-ethyl acetate (90 + 10) and visualized by spraying with 2,6-dichloroquinone chloroimide. TCP gives a characteristic blue-violet spot when heated at 100 degrees C for 15 min. The method is direct and sensitive and can be used to detect as low as 2.5 micrograms TCP or TOCP (tri-o-cresyl phosphate). GC was carried out using 10% OV-101 as the stationary phase and flame ionization detection for confirmation and quantitation of TOCP in oils.     

Microwave drying of selected greens and their sensory characteristics

Green leafy vegetables which supply minerals and vitamins to the diet, are highly perishable. Therefore, post harvest losses are extremely high. Limited studies are available in the literature with regard to preservation of greens.The effect of microwave drying and storage on physical and sensory properties of selected greens (coriander, mint, fenugreek, amaranth and shepu) were therefore studied. Microwave drying was carried out at 100% power and a frequency of 2450 mHz. The drying time varied from 10 to 16 min for different greens. Microwave drying affected color, appearance and odor of all the greens. The relative reconstitution capacity (RRC) for different greens was coriander-10.3, mint-10.3, amaranth-38.3, fenugreek-31.7 and shepu-32.8. The RRC appeared to influence acceptability. Coriander and mint, which exhibited the lowest RRC (10.3%), had the lowest scores for flavor and color while amaranth, with the highest RRC (38.3%), had scores similar to those of fresh amaranth. Scores for the products prepared with dried fenugreek and shepu,although low, were not statistically significant. Microwave drying was highly suitable for greens such as amaranth; moderately suitable for shepu and fenugreek and less suitable for coriander and mint.     

A qualitative colorimetric test for brominated vegetable oil in soft drinks

A simple and precise method of detecting brominated vegetable oil (BVO) in soft drinks is described. After extraction of BVO using diethyl ether, the concentrated ethereal solution was treated with a small quantity of zinc dust to convert the organic bromide to inorganic form; the solution was subsequently treated with lead dioxide to liberate bromine. The bromine evolved was detected by means of fluorescein-impregnated filter paper strip that turns pink because eosin is formed. The test can detect as low as 10 ppm (2 mg/200 ml) of BVO under experimental conditions. Gas chromatography was carried out on sodium methoxide derivatives prepared from ether extract for quantitation.