COMPARISON OF PROVITAMIN-A DETERMINATION BY NORMAL-PHASE GRAVITY-FLOW COLUMN CHROMATOGRAPHY AND REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

The provitamin A content of some food samples was determined by methods involving MgO:Hyflosupercel gravity-flow column chromatography (GFCC) and reversed phase high performance liquid chromatography (HPLC), the quantitation being done by external standardization (HPLC-ES) or internal standardization (HPLC-IS) with Sudan. The results obtained with alpha- and beta-carotene in carrots, beta-carotene and beta-cryptoxanthin in papaya and beta-carotene in tomato and kale agreed well, showing that any of the these techniques can be used, provided the analysis is done under optimum conditions. Good separation of the different provitamins using GFCC depends on the analyst's skill and visual acuity. HPLC-ES required a constant supply of provitamin standards, thus the varying purity of commercially available standards and the high instability of these compounds could pose grave problems. Due to the stability of Sudan, HPLC-IS appeared to be the method of choice although passage of the extract through a MgO: Hyflosupercel minicolumn was required prior to injection to separate chlorophylls, dihydroxy- and polyoxycarotenoids which would otherwise elute with Sudan. Nonconformity of the Sudan structure to those of the provitamins did not effect the quantitative results. The chromatographic separation, identity and quantification of the provitamins could be more easily established by using HPLC-IS, complemented with GFCC.334173213313

Occurrence of aflatoxin M(1) in milk and dairy products commercialized in Campinas, Brazil

One hundred and fifty-two samples of pasteurized milk, powdered milk, cheese and yoghurt, marketed in Campinas, Brazil in 1989-1990, were analysed for aflatoxin M(1) by the AOAC TLC method (visual quantitation) 980.21. Fifty-two pasteurized milk samples were also analysed in 1992 by the AOAC HPLC method 986.16. Aflatoxin M(1) was not detected in the 1989-1990 samples. Four milk samples of the 1992 batch were contaminated at 73-370 ng/l. Except for the sample with 370 ng/l, which would have been also found positive by the TLC method, the detection of aflatoxin M(1) in 1992 reflects the higher sensitivity of the HPLC method, not a greater occurrence of the toxin. Contamination of milk and milk products with aflatoxin M(1) does not appear to be a serious public health problem in the city of Campinas at the moment.13216917

EVALUATION OF SOYBEAN OIL DEORDIZATION DESTILLATE FOR VITAMIN-E RECOVERY

Deodorizer destillate, a by product of the sor bean oil refining process, was demonstrated to be a good raw material for production of vitamin E. In this paper we report the composition of tocopherols, free fatty acids, unsaponifiable matter and some physicochemical properties of the deodorizer destillates from three industrial samples obtained from industries in the State of Sao Paulo. Diferences in the destillates were total tocopherol and isomers of observed for unsaponifiable matter, tocopherol (alpha,beta,gamma,delta) between the samples. This allowed us to select the mast suitable sample for further studies as a vitamin E source. Analysis of the destillate samples showed an unsaponifiable matter of 27.1%, 18.6% and 3.5% and total tocopherol of 8.6%, 9.3% and 3.7% respectively. The sample that contained 9.3% of total tacopherol and 1.1% of a-tocopherol was selected as the most suitable for vitamin E recovery research.3741003101

Cytotoxic activity of Guettarda pohliana Mull. Arg. (Rubiaceae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The cytotoxic activity of crude extracts and their fractions from leaves and roots of G. pohliana was assessed against nine human cancer cell lines: melanoma (UACC-62), breast (MCF-7), breast expressing the multidrug resistance phenotype (NCI-ADR), lung (NCI-460), prostate (PCO-3), kidney (786-0), ovarian (OVCAR), colon (HT-29) and leukaemia (K-562). The hexane fraction from leaves (HL) and ethyl acetate (EAR), chloroform (CR) and hydromethanolic (HMR) fractions from roots were the most active fractions against K-562 with GI(50) values being lower than 1gmL(-1). Also, CR and HMR fractions were active against UACC-62 cell line in the same order of magnitude. The phytochemical study of the CR fraction allowed identifying the known iridoids secoxyloganin, sweroside and loganin.271816771681Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES