棚元 憲一

Food manufacturing enzymes are named according to enzyme functions in Japan. Active enzyme proteins are not identified as substances. Therefore, in the List of Existing Food Additives, most items consist of enzymes from different origins. If a chemical analysis of proteins in enzyme products can identify origins, the method will be a probable candidate for a simple identification test for enzyme origins. SDS-PAGE was applied to α-amylases, β-amylases, catalases, β-galactosidases, glucoamylases, cellulases, proteases, and hemicellulases. As many products as possible were collected to cover most of currently circulating products in Japan. One hundred and three products available in Japan were analyzed by SDS-PAGE. Molecular weights of major proteins were calculated. Characteristic electrophoresis patterns were found in most products. Useful information on relationships between origins and separation patterns of proteins was obtained. Identification of species was achieved for all products from plants and many products from bacteria or fungi although identification was limited to the genera level for some microorganisms like Bacillus.

Ozokerite, a natural gum base used as a food additive, is described as a purified wax substance found in veins of wax shale and is composed mainly of C₂₉-C₅₃ hydrocarbons, in the Notice (1996) relating to existing food additives in Japan. In order to evaluate the quality of commercially available ozokerite, we have analyzed the constituents. GC/MS analysis of ozokerite showed that the main components were saturated C₂₂-C₃₈ hydrocarbons, while the minor components were saturated C₃₉-C₅₈ hydrocarbons. The range of carbon numbers observed in the main saturated hydrocarbons was lower than those referred to in the Notice. The total concentration of the main saturated C₂₂-C₃₈ hydrocarbons was found, by GC/FID analysis, to be 81%.

MyD88およびIRAK-1により誘導されるNF-<SUB>k</SUB>Bの活性化にどのような機序でTRAF6が関与するのかを解説した。

ヘッドスペースガスクロマトグラフィー(HS-GC法)は薬品、食品添加物および食品中の残留溶媒の分析法として頻繁に用いられている方法である。本研究では、増粘安定剤(カロブビーンガム、グアーガム、ジェランガム)中のメタノールおよび2-プロパノールを分析対象とし、標準添加法を用いたヘッドスペースガスクロマトグラフィー法(HS-GC法)および水で蒸留後、留液をガスクロマトグラフィーで分析する方法(蒸留-GC法)により分析し、両方法で得られる溶媒量の比較検討を行った。その結果、HS-GC法と蒸留-GC法ではほぼ同程度の溶媒量が検出された。以上の結果から、増粘安定剤のような粘性の高い試料に対して、標準添加法によるHS-GC法は蒸留-GC法などと同等有用な方法であると考えられた。また、いずれの分析法においてもキャピラリーカラム(Aquatic-2ジーエルサイエンス(株))を用いて良好な分離が得られた。

In Europe, semicarbazide (SEM) was detected from bottled baby foods. SEM is a thermal degradation product of azodicarbonamide which is a foaming agent for plastic gaskets on metal lids. In this paper, a determination method of SEM by the incremental standard addition technique was established. And SEM in 64 of bottled foods marketed in Japan were surveyed. In the bottled baby food, SEM was detected 5.7-46.7 μg/g in 9 samples, and not detected in 2 samples. This contamination level is almost the same as that of the investigation in EU. In the general bottled food, SEM was detected 0.6-45.2 μg/g in 23 samples, and not detected in 30 samples. This level was slightly higher compared with that of EU. In all the bottled foods containing SEM, SEM or hydrazodicarbonamide was detected also from their sealing gasket. These results indicate that SEM detected from bottled food is degradation product of ADC added to the sealing gasket.

In order to set official analytical method in foods, the method of determining polysorbates(PSs) with rapid screening test by TLC and colorimetric assay were developed. PSs were extracted from processed foods with acetonitrile containing methanol. The extract was cleaned up on an alumina column (aluminum oxide, basic, 10g) and a silica gel cartridge (Sep-Pak Plus Silica, 690mg) to remove food color and other interfering substance. Suitable conditions of TLC to determine PS were as follow: adsorbent, silica gel ; developing solvent, dichloromethane -methanol -acetone -water (100 : 20 : 15 : 3) mixture; color development, Dragendorff reagent. The content of PS was obtained by colorimetric assay - cobalt thiocyanate method with PS80 as a standard substance. The recoveries of PS80 from eleven kinds of foods fortified at the level of 0.1 g/kg were 48.8-76.2% except 24.6% for a freezed dry food. The proposed method was applied to cocoa mix containg PS60. PS was confirmed at 0.26g/kg as PS80.

In our previous study, we reported a rapid screening test method of polysorbates (PSs) using TLC. Although the method is useful in terms of obtaining characteristic spot pattern of PSs, it is impossible to discriminate each polysorbate (PS20, 40, 60, 80, 65 or 85) and to identify the molecular species in PSs. Thus we developed a new qualitative analytical method of PSs using LC/MS. PSs were separated on a YMC pack C8 column (150 mm × 2.0 mm I.D., 5 μm, 30 nm) by a gradient elution with a mixture of water-methanol containing 0.1% formic acid. PSs were analyzed in selected ion monitoring (SIM) mode, with Na⁺ adducts produced by electrospray ionization. Selected ion was calculated from the molecule consisting of Na⁺ adducts of 20 oxyethylene (EO) sorbitan (So) mono-, di-, or tri-ester of fatty acids (FA) (So-EO(20)-FA(1〜3)), respectively. the SIM peak of each PS was eluted at different retention time by constituent FA and esterification degree of PS and the PS with different length of EO (12〜35) was found in each SIM peak. Using the method we tried to identify the molecular species in the spots obtained by TLC analysis of PS40. Two major spots of TLC prepared by preparative thin layer chromatography (PTLC) were revealed to contain So-EO(20)-monopalmitate or So-EO(20)-dipalmitate by LC/MS. We also analyzed the extract from cocoa mix containing PS60 in SIM mode by LC/MS and found that it contained So-EO(20)-monostearate, tristearate and monopalmitate, the constituents of PS60. These results show that LC/MS analysis in SIM mode using Na⁺ adducts of So-EO(20)-FA(1〜3) as selected ions is useful not only for the analysis of compositional profile of PS itself, but for qualitative analysis of PS in food.

低エンドトキシン活性を示す<I>Helicobacter pylori</I>リポ多糖の炎症反応惹起機構について解説した。

エンドトキシンによって誘導される血管内皮細胞のアポトーシスを解説した。

TLR4強制発現細胞を用いた血中エンドトキシン活性測定法について解説した。

Eight kinds of polylactide (PLA) made by two manufactures were studied on their properties of pellets and sheets. Their relative viscosity (Rv) values against chloroform were from 2.8 to 4.1, and molecular weight (Mw) were from 120,000 to 160,000. The D-lactic acid contents of sheets were from less than 1% to 11.3%. There was the correlation between Rv value and Mw, except a sheet produced by higher content of D-lactic acid, which showed lower Rv value. Residues of free lactide were 169-1610 μg/g in the sheets. On metal analysis, all sheets contained tin, but no other special metal. It was suggested that 2-ethylhexanoic acid tin (II) salt was used as catalyst in their polymerization. The levels of tin were from 3.4 to 31.8 μg/g, however migration into 4% acetic acid was not observed. In the overall migration test and the consumption of potassium permanganate test, each sample showed low levels. Lactic acid and lactide which were expected to be main migrants were not estimated by overall migration test, because they were vaporized during the heating at 105℃. It is, therefore, necessary to establish the migration test for lactic acid and lactide.

MD-2非発現細胞における新しいLPS認識機構について解説した。

IRAK-1過剰発現によるTRAF6蛋白のproteasome依存性の減少機構について解説した。