The effect of freezing speed and storage temperature on the degradation of eight kinds of refrigerated foods was examined using two ¹H-NMR relaxation methods, line width measurement and pulse NMR. The comparison of line width and relaxation time, ΔH and T₂, suggested that freezing process should be interpreted in two different temperature ranges. The freezing speed was defined by the passage time from -1℃ to -5℃. The amount of "mobile water molecules" was compared using pulse NMR data between -1℃ and -5℃. The preferable effect of fast freezing was revealed in bamboo shoot and potatoes in consistent with the sensory test. The amount of mobile water was considered as the rate determining factor on the growth of ice crystals. The effect of storage temperature was examined between -13℃ and -28℃ and the mobility of "mobile water molecules" was compared according to ΔH and T₂ data. The mobility was found to be superior factor on the growth of ice crystals under such low temperature range. The storage temperature effect was revealed in bamboo shoot and cod in consistent with the sensory test. It was suggested that NMR relaxation methods were useful means to anticipate the degradation of foods during refrigeration if they were properly used.

View full abstract

Real-time PCR method and ELISA method for quantitative determination of genetically modified soybean (CMS) and de-fatted soybean were compared. CMS contents in mixed soybean grain samples, IRMM standard, ELISA standard and IP handling soybean were determined using real-time PCR method and ELISA method. In soybean grain samples, a high correlation between GMS contents determined using real-time PCR method and ELISA method was observed. On the other hand, no correlation was observed between the GMS contents (%) determined using real-time PCR method and ELISA method in de-fatted soybean samples. These results suggested that both real-time PCR method and ELISA method would be applicable for the determination of GMS contents in soybean grain samples, but the values determined using real-time PCR method seem to be higher than those using ELISA method in de-fatted soybean samples.

View full abstract

HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase (EC 1.1.1.34) inhibitors (statins) are used for hypercholestemia. HMG-CoA reductase is the rate-limiting enzyme of cholesterol biosynthesis. Rhabdomyolysis is one of the most serious side effects by statins. On the other hand, vitamins are used widely and easily for supplements of nutrition in daily use. Statins are one of the most marketable drugs for hypercholesterolemia. Vitamins are taken without prescription as supplements of nutrition ; the patient who prescribed statins may take vitamins. So the interaction with statins and vitamins were studied by using the in vitro assay system with L6 rat myoblasts. The myopathy was increased by the presence of vitamin A, vitamin D and nicotinic acid. Especially the severe injury was induced to the cells by vitamin A and vitamin D. The other vitamins, vitamin B₁, B₆, B₁₂, vitamin C and vitamin E did not show the reaction on the L6 cells. Taking vitamins together with statins increase the risk of rhabdomyolysis. The results of this study suggest that it is desirable for the person takes statins not to take vitamin A, vitamin D and nicotinic acid.

View full abstract

Garcinia extract, which is extracted from the rind of the Indian fruit, Garcinia cambogia, is available as an herbal supplement and is used to reduce weight. In the present study, free-type or Ca-type Garcinia extract was fed to F344/DuCrj male rats at a dose of 0.2%, 1.0% or 5.0% as a dietary admixture for 13 or 26 weeks, in order to study their toxicity. 1. No mortality during the administration period was observed in all groups including control. Soft stool was sporadically observed in all groups. 2. Body weight gain was suppressed only in the 5.0% of Ca-type extract given group on 1-, 4- and 10-week, and lowered body weight was observed on 4-between 8-week and on 10-between 12-week. 3. There were no toxicological changes in food consumption, in intake of Garcinia extract, in hematology, in blood chemistry and in organ weights. 4. As a result of toxicokinetics, (-)-hydroxycitric acid concentrations in plasma were almost or less than detection (20μg/mL) limit in each group. 5. The pathological examination revealed no marked changes in the gross findings in free-type extract given group on 13- or on 26-week. In 5.0% of Ca-type given group on 26-week, there was one case showing small size of testes, seminal vesicle, prostate and soft testes. 6. As a result of the histological examination, there were no toxicological changes in free-type extract given group on 13- or 26-week. In 5.0% of Ca-type given group on 13-week, there were seven cases showing very slight or slight atrophy of seminiferous tubules, on 26-week, one case had interstitial edema in testes, decreased sperm counts in epididymides, atrophy of seminiferous tubules, seminal vesicle, prostate, 4 cases showed very slight or slight atrophy of seminiferous tubules. These results indicate that the no adverse effect level of free-type Garcinia extract was 5.0% and that of Ca-type Garcinia extract was 1.0%, under the conditions of this study.

View full abstract

A spectrophotometric method was improved for determination of cyanide in foods using picric acid test strips. Cyanide in a food sample reacted with acid to produce hydrocyanic acid (HCN). The HCN vapors reacted with the picric acid and formed red color on a test strip. The red colored compound was extracted with 50% aqueous ethanol solution. The extract was measured absorbance at 500 nm. A linear relationship was obtained between the range of 1-15μg CN. The recoveries of cyanide from various foods fortified at the level of 0.5 and 5.0μg CN/g were 68.3-98.4% and 73.1-99.7%, respectively. The limit of determination in actual sample was 0.5-1.0μg CN. The method was successfully applied to quantitative determination of cyanide in bean paste, beans, health foods, and grain. This method is simple and useful for the routine analysis of cyanide in foods.

View full abstract

About 70% of total lipids in porphyra yezoensis, which is processed for use as edible sea alga, is composed with three types of glycolipids : MGDG (monogalactosyldiacylglycerol), DGDG (digalactosyldiacylglycerol), and SQDG (sulfoquinovosylgalactosyldiacylglycerol). In these glycolipids, SQDG is reported as an inhibitor of DNA synthesis. In this paper, with the aim of studying more about the physiological functions of SQDG extracted from sea alga (A-SQDG), we investigate its effects on the growth and differentiation of murine neuroblastoma cells (Neuro2a). These glycolipids (MGDG, DGDG, and SQDG) extracted from sea alga inhibited the cell growth of Neuro2a, but this inhibition was most potent in A-SQDG, which was extracted from alga. We therefore compared this inhibitory effect of A-SQDG with S-SQDG or C-SQDG extracted from spinach or chlorella, respectively. It was found that A-SQDG and S-SQDG had an equivalent inhibitory effect on cell growth, but C-SQDG had none at all. Furthermore, we investigated the effects of these three types of SQDG on neuritogenesis in Neuro2a cells. We found that A-SQDG revealed a potent effect on neuritogenesis than that by retinoic acid (RA) known as a potent reagent of neuritogenesis. It was also found that S-SQDG revealed the same degree of neuritogenesis as RA, but no neuritogenesis could be found in C-SQDG. The different effects of these three types of SQDG are thought to be originated in their molecular compositions of acyl group. The caspase-3 activity was known as a maker enzyme of apoptosis. As a result, A-SQDG, S-SQDG and C-SQDG almost inhibited etoposide-induced apoptosis. These SQDG were expected to be reagents to prevent neuronal cell death in Alzheimer's disease.

View full abstract

Multi residue method for determining 22 pesticides in agricultural products was examined using high performance liquid chromatograph(HPLC) with photodiode array detector(PDA). Twenty-two kinds of pesticides were divided into 3 groups. They had 0.01〜0.04μg/ml of detective limits using S/N = 3, and showed straight working curves at 3 concentrations of 0.1, 0.5, 1.0μg/ml. Except for 3 pesticides, all were eluted in the 70-140 ml fraction from gel permeation chromatography(GPC) with ethylacetate/cyclohexane (50/50 (v/v)). Chlorfluazuron, flufenoxuron, and hexaflumuron were eluted in the 65-100 ml because of their higher molecular weight. All pesticides were eluted in the 0-25 ml fraction from the mini-column including graphitized carbon black and aminopropyl with toluene / ethyl acetate (10/90 (v/v)). We used this solvent instead of toluene / acetonitrile (25/75 (v/v)). This method is following ; a sample was extracted with acetone / water (70/30 (v/v)), concentrated under reduced pressure and extracted with ethyl acetate / hexane (50/50 (v/v)). The solution was dehydrated with sodium sulfate anhydrous, concentrated under reduced pressure, dissolved in the GPC mobiled phase, and cleaned up by GPC. The fraction of pesticide was concentrated under reduced pressure, dissolved in toluene / ethyl acetate (10/90 (v/v)), cleaned up with the mini-colomn. The solution eluted was concentrated under reduced pressure, dissolved in acetonitrile, and determined with HPLC. We analyzed 9 kinds of agricultural products fortified with 22 pesticides using this method, and got approximately good recoveries in 7 kinds of them as tomato, spinach et al. The HPLC solutions of onion and orange had many peaks caused by matrix on HPLC chromatograms, and we didn't determine recoveries, when they overlapped the peaks of pesticide. We applied this method into 15 kinds of marketed agricultural products, and this method was applicable except for grapefluit. To conclude, this method was considerd to be satisfied for simultaneous method for multi pesticide residues.

View full abstract