Vanillin content in boiled peanuts.

A high-performance liquid chromatographic (HPLC) method for determination of vanillin in boiled peanuts has been developed. Vanillin was extracted with acetonitrile by blending at high speed followed by purification of an aliquot of the extract on a minicolumn packed with Al(2)O(3). Vanillin was quantitated by HPLC on silica gel with n-hexane/2-propanol/water/acetic acid (2100/540/37/2, v/v) as a mobile phase. The recovery of vanillin added to fresh peanut hulls at 0.50 and 2.50 microg/g was 78.7 +/- 2.7 and 79.9 +/- 3.1%, respectively. The detection limit of vanillin in boiled peanuts was estimated at 0.05 microg/g. UV-detector response to vanillin was linear to at least 2.5 microg/injection. Free vanillin has been found in two commercial brands of boiled peanuts at low ppm levels. Both the kernels and the hulls contained vanillin, which was formed during hydrolysis of lignin, one of the major constituents of the peanut hulls. Since vanillin has a low flavor threshold, it could be considered as one of the major ingredients that determines the flavor of boiled peanuts.

trans-resveratrol content in commercial peanuts and peanut products.

A modified high-performance liquid chromatographic (HPLC) method for determination of trans-resveratrol (resveratrol) in peanuts and peanut products has been developed. Resveratrol was extracted with acetonitrile-water (90/10, v/v) by blending with diatomaceous earth at high speed followed by purification of an aliquot of the extract on a minicolumn packed with Al(2)O(3)-ODS (C(18)) mixture. The column was eluted with acetonitrile-water (90/10, v/v), eluate was evaporated under nitrogen, and residue was dissolved in HPLC mobile phase. Resveratrol in an aliquot of purified extract was quantitated by HPLC on silica gel with n-hexane-2-propanol-water-acetonitrile-acetic acid (1050/270/17/5/1, v/v) as a mobile phase. The recovery of resveratrol added to diatomaceous earth at 0.05 microg/g was 98.95 +/- 17.79%; the recovery of the standard added to fresh peanuts (with 0.070 microg/g natural level of resveratrol) at 0.50, 5.00, and 10.00 microg/g was 117.23 +/- 8.87, 100.10 +/- 2.49, and 100.45 +/- 1.51%, respectively. The quantitation limit of resveratrol in fresh peanuts was about 0. 01 microg/g. Roasted peanuts had the lowest content of resveratrol of 0.055 +/- 0.023 microg/g (n = 21), while in peanut butter its concentration was significantly higher, 0.324 +/- 0.129 microg/g (n = 46), and boiled peanuts had the highest level of 5.138 +/- 2.849 microg/g (n = 12). Resveratrol content in commercial peanut products was similar to the resveratrol content of the raw peanut fractions routinely used for making them.

[A method of determining the levels of deoxynivalenol (vomitoxin) and its metabolites]. / Metod opredeleniia dezoksinivalenola (vomitoksina) i ego metabolitov.

A method has been developed for assay of deoxynivalenol (DON) and its metabolite desepoxideoxynivalenol (DOM-1) in animal excrements with the use of reversed-phase high-performance liquid chromatography with UV-detection (218 nm). The method includes purification in the mini-column with activated carbon and aluminium oxide. The detection limit was 50 ng/g, relative standard deviation--0.05-0.1, the degree of toxin isolation--76-89%. DON isolated from Fusarium macroceras, strain 579a, cultivated in rice under laboratory conditions, and DOM-1 obtained as a result of DON incubation with the contents of the beef first stomach, were used in the study. The structure of toxins isolated has been proved by the mass-spectrometry method. The method developed by the authors was used in the study of DON metabolism in vivo in monkeys.

[The effect of the trichothecene mycotoxin deoxynivalenol (vomitoxin) on calcium homeostasis, vitamin D metabolism and receptors in rats]. / Vliianie trikhotetsenovogo mikotoksina dezoksinivalenola (vomitoksina) na gomeostaz kal'tsiia, obmen i retseptsiiu vitamina D u krys.

Metabolism of calcium and vitamin D was studied in young rats administered with trichothecene-related mycotoxin deoxynivalenol (vomitoxin) at a daily dose of 10 mg/kg perorally within 7 days. The vomitoxin treatment caused a moderate hypocalcemia, a decreased absorption of calcium in small intestine as well as led to decrease of alkaline phosphatase activity in blood and small intestine mucosal membrane. Density and saturation of bone tissue with minerals were not altered. Concentration of 25-OHD in blood and activity of vitamin D3(25)-hydroxylase in liver tissue were decreased by 40% and 30%, respectively. Development of 1,25(OH)2D3 and 24,25(OH)2D3 as well as concentration of total and free 1,25(OH)2D3 receptors were not altered in kidney. At the same time, these impairments of calcium and vitamin D metabolism were prevented by providing high content of vitamin D in the ration--0.25 mg/kg of food. Impairments in calcium metabolism caused by vomitoxin may be partially related to development of a secondary deficiency in vitamin D.

A survey of the occurrence of deoxynivalenol in wheat from 1986-1988 harvests in the USSR.

The occurrence of deoxynivalenol (DON; vomitoxin) in wheat from 1986-1988 harvests in the USSR was surveyed. A significant frequency of DON contamination (81.3% of samples analyzed) was observed. A correlation between levels of DON contamination and percentage of Fusarium-damaged kernels was demonstrated. It was shown that DON contamination did not exceed the maximum tolerated level (MTL) established in the USSR (1.0 mg/kg) if samples contained no more than 0.6% of Fusarium-damaged kernels.

[The contamination of the 1986-1988 wheat harvests with deoxynivalenol (vomitoxin)]. / Izuchenie zagriazneniia pshenitsy urozhaev 1986--1988 gg. dezoksinivalenolom (vomitoksinom).

The authors used high-performance liquid chromatography to estimate the content of deoxynivalenol (vomitoxin) trichothecene mycotoxin in 175 samples of wheat harvested in the Krasnodar Territory in 1986-1988. High incidence rates and levels of wheat intoxication have been recorded: 42.8% in 1986, 25% in 1987, and 80.28% of wheat samples in 1988 contained deoxynivalenol in concentrations exceeding MPC (1 mg/kg). A correlation was noted between the degree of wheat affection with Fusarium and the level of its intoxication with deoxynivalenol. A conclusion has been made on the necessity of using the criteria of the degree of wheat affection with Fusarium and the level of its intoxication with deoxynivalenol in hygienic recommendations for safe utilization of fusarial grain for food purposes.

A survey using normal-phase high-performance liquid chromatography of aflatoxins in domestic and imported foods in the USSR.

A survey of the occurrence of aflatoxins B1, B2, G1 and G2 in Soviet domestic and imported cereals and nuts (totalling 4532 samples) collected in 1985-87, showed that 26.9% of imported peanuts, 2.2% of corn and 28.3% of cotton seeds were contaminated by aflatoxins at levels exceeding the maximum tolerated level established in the USSR (5 micrograms/kg for aflatoxin B1 in foodstuffs of all types excluding baby foods); maximum concentrations were 3650, 600 and 153 micrograms/kg, respectively. A highly sensitive normal-phase high-performance liquid chromatographic method was developed. The detection limit was 0.1 microgram/kg and the coefficients of variation were 11% and 8.5% at contamination levels 10 and 100 micrograms/kg of aflatoxin B1, respectively.

[Determination of epoxide hydrolase activity by high performance liquid chromatography]. / Opredelenie aktivnosti époksidgidrolazy s ispol'zovaniem vysokoéffektivnoi zhidkostnoi khromatografii.

A new highly sensitive method of microsomal epoxide hydrolase activity has been worked out. The product of styrene oxide enzyme hydrolysis--phenylethyleneglycol (PEG) was extracted by n-butanol, and its aliquot was analysed by high-performance liquid-chromatography on Silica Gel using hexane-isopropanol-water (80:28:2) mobile phase. PEG was detected at 210 nm. The detection limit of PEG was 5 pmol per injection. The coefficient of variation of the method was 3.7%.

[Comparative characteristics of microsomal epoxide hydrolase in the rat liver and small intestine mucosa]. / Sravnitel'naia kharakteristika mikrosomal'noi époksidgidrolazy pecheni i slizistoi obolochki tonkoi kishki krys.

Activity of epoxide hydrolase was studied in microsomes of rat liver and small intestinal mucosa with styrene oxide as substrate using high performance liquid chromatography. Specific activity of epoxide hydrolase in microsomes from small intestine constituted 5-10% of the activity in liver microsomes. Both these enzymes had similar kinetic parameters, the same pH optimum around pH 8.7; their activity was altered only slightly in presence of anionic detergents. The enzyme activity was increased in liver and small intestine after administration of benzyl, trans-stilbene oxide, 2-acetamidofluorene and butylated hydroxytoluene. 1,2-epoxy-3,3,3-trichloropropane and 2-brom-4-nitroacetophenon inhibited similarly epoxide hydrolase in hepatic and intestinal microsomes. Cyclohexene oxide inhibited both these enzymes by the non-competitive type, exhibiting the higher affinity to liver epoxide hydrolase.

Laser Doppler velocimeter as an optoelectronic data processing system.

Using Fourier optics, the conditions of the laser Doppler velocimeter (LDV) optimization in relation to the scattering center size, laser parameters, and photoreceiver aperture are found. The measurement errors are estimated for average and instantaneous velocities with regard to the statistics of the scatterers. The compensating scheme, which eliminates a low-frequency component of the signal and laser noise, is described. The results of its experimental applications are given.