Keywords L-A scorbic acid determination ; spectrophotometry ; ammonium molybdate reagent ; vegetables and fruitsThe reported methods for the determination of L-ascorbic acid in fruits and vegetables include titrimetryl-3 and spectroph~tometry.*-~ The widely used titrimetric method1 using 2,6dichlorophenolindophenol is subject to interference by other reducing substances.8 Further, the method is laborious and the standard dye solution is unstable and requires standardisation before use.' The specificity of the method using N-bromosuccinimide2 is no better6 owing to its reaction with olefinic and phenolic cornpound~.~~~0 L-Ascorbic acid has also been determined as the molybdophosphate complexll and with Folin -Ciocalteu reagent.12 Ammonium molybdate has been used for the detectionl3 and determination of ascorbic acid in pharmaceutical ~reparati0ns.l~ We have found that the methods using ammonium molybdate and Folin -Ciocalteu reagents cannot be used directly for the determination of ascorbic acid in fruits and vegetables owing to interference by various reducing agents. In this paper a modification of the ammonium molybdate method to minimise these interferences is reported. Experimental Apparatuspath length 1 cm and volume 10 ml.Spectrophotometer. Bausch and Lomb Spectronic-20 spectrophotometer with a cell of ReagentsAll reagents used were of analytical-reagent grade. Ammonium molybdate solution, 5% m/V. Oxalic acid solution, 0.05 M. Sulphuric acid, 5% VlV. Metaphosphoric acidacetic acid solution.Freshly prepared and containing 0.2 mM EDTA.Dissolve, with shaking, 15 g of metaphosphoric acid pellets or freshly pulverised sticks in 40 ml of acetic acid and 200 ml of water, dilute to 500 ml with water and then filter.Freshly prepared.This reagent can be kept for 3 d in a refrigerator.Standard L-ascorbic acid solution, 0.1% m/V in the oxalic acid -EDTA solution. ProceduresPreparation of calibration graph into separate 25-ml calibrated flasks. Pipette 0.1-, 0.2-, 0.3-, 0.4-, 0.5-and 0.6-ml aliquots of the standard L-ascorbic acid solution Add sufficient oxalic acid -EDTA solution to give a

Presence of gallic acid, ellagic acid, corilagin and related ellagitannins, 3,6hexahydroxydiphenoyl-glucose and its isomer, 4,6-hexahydroxydiphenoyl glzrcose, 1-galloyl glucose, 3-galloyl glucose and qtlercetin is reported in the alcoholic extraxt of Jambul seeds. Acetone extract of the bark and seeds contain partially methylated derivatives of ellagic acid i.e. 3,3'-di-0-methyl ellagic acid and 3,3', 4-tri-0-methyl ellagic acid. Alcoholic extraction of tannins results into their extensive degradation into simple phenolic compounds. Jambul (Syzygium cumini SKEELS, Myrtaceae) seeds are known for their medicinal characters to cure diabetes, diarrhoea, dysentry and blood pressure [I]. JAGODZINSKI et al. [2] isolated a principle from Jambul seeds which abolished the glycosurea, hyperglycemia and reduced the polydepsia which occurred in diabetic rats. LAL and CHAUDHURI [3] have reported that the Ja~nbul seeds extracts are capable of lowering blood pressure to the extent of 34.6%. Recent studies with ellagic acid (a phenolic acid) by BHARGAVA et al. [4] have shown that it markedly lowers the blood pressure. In order to ascertain which particular phenolic compounds in Jambul seeds are responsible for their medicinal character, a series of investigations has been started. In the present paper, a detailed account of the polyphenols, present in the seeds, and bark is being reported. Experimental Melting points are uncorrected, U.V. spectra are recorded in ethanol by Hilger and Watts Spectrophotometer and log E values are given in parenthesis. I.R. spectra are recorded in nujol by Perkin-Elmer infracord; only main peaks are cited. Alcoholic extraction The dried seeds (100 g) were extracted with 70% ethanol (500 ml), the extract was concentrated

A simple and accurate colorimetric method has been developed for quantitative determination of capsaicin in capsicum fruits. The method does not involve prior isolation of capsaicin from green capsicum fruits, and interference due to pigments is accounted for by determining a blank. Interfering substances are removed from red capsicum fruits by column chromatography using basic alumina as adsorbent. Capsaicin from the ethyl acetate extract of dried fruits is determined by developing a yellow complex with sodium nitrite–sodium molybdate reagent, which is read at 430 nm. Lambert-Beer’s law is obeyed in the concentration range 1.5–33.5 μg capsaicin/mL. The method is reproducible and is applicable to the rapid determination of capsaicin content.

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