Probiotics have been defined as live microbial food supplements that have been shown to benefit human health. Probiotic products are marketed widely throughout the world. Until recently, probiotics were mainly selected on the basis of technological properties and resistance to acid and bile and were used in products aimed at promoting the well-being of consumers. However, now research efforts are focusing on the development of probiotics with special functional properties. Lactobacillus gasseri OLL2716 (LG21) was selected as a promising probiotic for Helicobacter pylori infection by in vitro and animal studies. The effects of yogurt containing LG21 on H. pylori infection in humans were examined. The ingestion of yogurt containing LG21 decreases the number of H. pylori and alleviates mucosal inflammation in the stomach. LG21 was shown to be effective as a probiotic for H. pylori infection.
Mechanical analysis of injury of spores of B. subtilis by quick decompression was investigated. The stress on the stress concentration point of germinated spores under 200, 300 and 400 MPa treatment was calculated to be 800 MPa, 1200 MPa and 1600 MPa, respectively, where this point was the highest point of stress concentration on the sporecoat. The stress showed values 4 times larger than treatment pressure. Sporecoat is a keratin-like scleroprotein. The tensile strengths of some polymers were 70 MPa (polyester), 50 MPa (vinyl chloride), 70 MPa (nylon) and 20 MPa (polyethylene). From stress analysis, minimum stress of the spore model on the stress concentration point (800 MPa) was higher than the tensile strength of the above polymers. It was indicated that the sporecoat is disrupted by the stresses produced by expansion of inner-spore-water with quick decompression.
This paper proposes a method for predicting the temperature in a metal can based upon the apparent viscosity of a liquid food, which was estimated from the initial temperature in the can under the condition where natural convection is taking place. In the absence of natural convection, we estimate its thermal diffusivity in a similar manner, and predict the temperature based on the estimation. We first evaluated the proposed method using water and glycerin. The viscosities estimated by this method agreed closely with the literature values. Subsequent experiments and analyses performed using four types of juice having different viscosities indicate the feasibility of predicting the temperature in the can. In addition, when we conducted experiments and observations regarding the flow of liquid using ink used as a tracer, the results agreed with the predictions whether natural convection was present or not.
The effects of repeated pressure treatment (RP treatment) and continuous pressure treatment (CP treatment) at 25°C, 400 MPa for 30 min on the breakdown of spore clumps were investigated and RP treatment was found to be effective in breaking the clumps as the ratio of clumps decreased with increase in decompression time. It was deduced that this breakdown effect was one reason for the higher sterilization effect of RP treatment than CP treatment.
Effects of light-colored (Usukuchi) andregular soy sauces(Koikuchi) on rheological properties of boiled foods were determined using a rheometer. The amounts of soy sauces were added to the ingredients with the same levels as those providing the highest and best scores for the sensory test. A taro corm, potato tuber, pumpkin fruit, Japanese radish root and carrot root were boiled according to a recipe in an electric cooker. Firmness of taro, potato and Japanese radish boiled with Usukuchi was significantly softer than that boiled with Koikuchi. The cooking time of taro with Koikuchi was longer than that with Usukuchi, but the tissue of taro boiled with Usukuchi was still softer. In a boiling test at the same NaCl concentration of 2.0% (w/w), the firmness of boiled potato decreased in order of NaCl alone solution, Usukuchi and Koikuchi solutions. Therefore, the taste or food texture of food boiled in Usukuchi might be due to the cooking property of this sauce, which softened the firmness of the boiled food as compared with that of Koikuchi. The cooking property of Usukuchi might be influenced by its higher concentration of NaCl, and also the co-existence of organic acids, amino acids and browning products.
Extraction of nattokinase, a fibrinolytic enzyme in natto bacillus, was attempted by the following 4 methods: 1) extraction with saline, 2) treatment with the organic solvents acetone, toluene and hexane prior to extraction, 3) alkaline treatment at pH 11.0 and, 4) autolysis in the presence of 0.1% NaN3 at 4\\xa1 C. Each fraction showed not only a strong fibrinolytic activity, but also H-D-Val-Leu-Lys-pNA and Suc-Ala-Ala-Pro-Phe-pNA amidolytic activities. Doses of 50–200 mg/kg natto bacillus (11011 active cells/g) were orally administered for rat experimental pulmonary thrombosis and to healthy human volunteers. A decrease in thrombus count and plasma euglobulin lysis time (ELT), as well as an increase in tissue plasminogen activator (t-PA), indicate that natto bacillus serves to activate plasma fibrinolysis in vivo.
Occurrence of polyphenol oxidase (PPO, o-diphenol: oxygen oxidoreductase, EC.184.108.40.206) in the fruits of nine cultivars of banana (Musa spp.) commercially cultivated in China was investigated. All banana fruits peel and pulp tested had PPO activity, and all PPO strongly oxidized dopamine and 3-hydroxytyramine (tyramine). However, very weak and/or no oxidative activity was recognized on such trihydroxybenzenes as phloroglucinol and gallic acid. Similar substrate specificity of PPOs toward phenolic compounds was detected in the pulp and peel of all banana cultivars tested. The specific PPO activities toward dopamine for pulp were between 5.11 and 25.72, and those of peel were between 6.75 and 26.86 units/mg protein. However, PPO activities toward dopamine in the pulp and peel of AAA and AA genome group bananas were higher than those of ABB and AAB groups. The changes of pulp and peel PPO activities during fruit development were also determined in the three banana cultivars. During this development a remarkable decrement in pulp and peel PPO activities was found in all banana cultivars used.
Maitake mushroom was cultivated on logs and in sawdust substrate. Comparisons of proximate compositions, content of free amino acid, 5′-nucleotides and vitamin D2 were conducted. Effects of the log and sawdust substrate compositions on the mushroom composition were also examined. Protein and ash in sawdust mushroom were significantly higher than that in the log mushroom. Protein content of fruit body cultivated on sawdust substrate was closely related to the content of the substrate. This fact well explained the difference in protein and ash contents between mushroom cultivated on log or sawdust substrate. Free amino acid content as MSG-like and sweetness components, and 5′-GMP were significantly higher in log mushroom. The content of vitamin D2 was appreciably higher in sawdust mushroom than that in log mushroom.
Using natural prawn (Penaeus japonicus), a comparison study was conducted between super chilling (2°C) and cool (5°C) storage for the effectiveness of keeping fish meat fresh. Brightness of the tail color could be retained longer using super chilling storage compared to traditional refrigeration. In addition, a significant color difference in a values between the two methods was confirmed when a colorimeter was used. As a physical property of the meat, significant softening was observed after 2 days refrigeration. However, in super chilling storage, no softening was observed even after 3 days of storage. Light microscopy showed the lowering of intercellular connections in the softened meat. The rise in K-values was suppressed in super chilling storage. From these results, it can be expected that super chilling storage is able to maintain the color of prawns and the physical properties of the meat, and consequently offers potential as a new storage technique suitable for replacing refrigeration.
The solubilization of cattle achilles tendon with actinidin was investigated under neutral and acidic conditions. 1.43 to 1.92 and 0.97 to 3.19% of collagen were solubilized by treating the cattle achilles tendon with actinidin at 20°C at pH 6.0 and 3.3, respectively. Furthermore, SDS-polyacrylamide gel electrophoresis of reaction mixtures with actinidin demonstrated that actinidin degraded the tendon into collagen subunit chain, β- and α-chain and peptide fragments of various sizes at 20°C at pH 6.0 and 3.3. These results indicated that actinidin could solubilize the insoluble collagen in unheated cattle achilles tendon at 20°C at pH 6.0 and 3.3 and that a large proportion of the resulting peptide fragments by actinidin seemed to be actinidin digests against elastin with a small contribution of hydroxyproline.
The application of ethylene to germinating seeds in the practical production of mungbean sprout has been used to get thicker, shorter and harder hypocotyls. In our experiment, a similar response was induced by 2-chloroethyl phosphonic acid treatment (2-CPA). Neutral sugar concentration of the pectin fraction was higher in 2-CPA-treated hypocotyls than in non-treated ones throughout the experiment, while uronic acid concentration in the 2-CPA-treated ones was slightly higher than that in the non-treated on days 3 and 5. In water-soluble pectin, a lower concentration of galactose and a higher concentration of arabinose and rhamnose (and/or xylose) in 2-CPA-treated hypocotyls as compared to the non-treated ones were observed on days 1 and 3. From these results, we hypothesized that the changes in neutral sugar concentration and composition of water-soluble pectin fraction by 2-CPA-treated might contribute to physical and/or morphological change in these hypocotyls.
Lactic acid bacteria (157 stock cultures) were screened for their ability to produce extracellular proteinase with milk-clotting activity. A strain identified as Enterococcus faecalis TUA2495L showed the highest ratio of milk-clotting activity (MCA) to proteinase activity (PA). The molecular weight of the purified enzyme from the strain was estimated to be 34–36 kDa by gel filtration and by SDS-PAGE. Its isoelectric point was about 5.4, and the Km value on casein (Hammarsten) was 0.61% (w/v). The optimum temperature was 70°C for MCA and 50°C for PA. The MCA increased with a decrease in the pH from 7.8 to 5.8 but the PA was optimum at pH 8.0–9.0. Both MCA and PA were stable within the pH range of 5.5–10.0. The enzyme was inhibited by heavy metal ions (Fe2, Cd2, Ni2, Cu2 and Al3), SDS and EDTA. Reactivation of the enzyme activity with Co2, Mn2 or Zn2 indicates the importance of these metals in the catalytic function of the enzyme. The enzyme was especially active on κ-casein, and SDS-PAGE analysis showed that the degradation patterns of κ-casein by Ec. faecalis enzyme and Mucor miehei milk-clotting enzyme were almost the same.
A method using solid-phase extraction (SPE) and GC-MS was developed for the determination of a series of polar and unstable flavor compounds: reductones, furans and volatile organic acids, in aqueous model matrices. The SPE procedures were optimized mainly on the pH-dependency of the analytes with regard to their adsorption characteristics. Good recovery of the reductones except DDMP was obtained at pH 2 and 4.5. Furan derivatives were generally recovered in high yields under the acidic to neutral pH conditions examined. All organic acids were recovered almost quantitatively at pH 2. An essentially comparable result was obtained in a model Maillard reaction mixture. In order to apply this method to alcoholic beverages, effect of the ethanol concentration on the SPE adsorption of the analytes was also investigated.
The effects of pH on the formation of maltol and furanmethanol as well as other minor reductones and furans on heating an aqueous solution of maltose under conditions in the absence (caramelization) and presence (Maillard reaction) of proline were examined. The experiments employing a pH-stat device clearly demonstrated the pH dependency on the formations of the products. The products of maltulose and proline-maltulose, which were postulated as the initial intermediates for the two pathways of maltose degradation in the presence of proline, were also examined. On the basis of the results, the reaction pathways of the formation of volatile products from maltose were discussed.
We prepared fermented lemon peel (FLP) with high antioxidative activity by fermentation of the lemon peel (LP) with Aspergillus saitoi. The antioxidative activity of LP and FLP was examined by the radical-scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) in vitro, and the suppressive effect against exercise-induced oxidative damage in rat liver. FLP exhibited higher radical-scavenging activity against DPPH than LP. The administration of LP and FLP prior to exercise significantly suppressed the increases in thiobarbituric acid-reactive substance caused by lipid peroxidation during exhaustive exercise, with FLP having a tendency of higher activity than LP. Moreover, FLP showed a significant suppressive effect of Ne-(hexanonyl)lysine content, a primary oxidative stress marker, which increases due to exhaustive exercise, whereas LP did not. The fermentation of LP with A. saitoi was thought to produce a high antioxidative activity. The high antioxidative activity of FLP was assumed to be related to the production of antioxidative flavonoids, as a hydroxyflavanone and aglycones, by the fermentation of lemon peel with Aspergillus saitoi.
Propolis is a resinous substance collected by honeybees from various plant sources. We examined the antioxidant activity of Japanese propolis from various areas of Japan: Hokkaido, Akita (Minamiakita and Kazuno), Fukushima (Aizuwakamatsu and Futaba), Gifu, Nagano, Tokyo, Kanagawa, Shizuoka, Okayama, Tottori, Fukuoka and Okinawa. We prepared ethanol extracts of propolis (EEP), and evaluated the antioxidant activity of EEP samples by the β-carotene bleaching and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay systems. Further, we identified the major constituents in EEP by HPLC analysis by a photodiode array (PDA) and mass spectrometric (MS) detection, and quantitatively analyzed each component. EEP from Akita (Minamiakita) and Okinawa had relatively strong antioxidant activity, and was correlated with total polyphenol contents. Propolis from Akita (Minamiakita) contained large amounts of the antioxidative compounds, caffeic acid and phenethyl caffeate. Propolis from Okinawa appeared to have antioxidants not seen in propolis from other areas.
Mannooligosaccharides (MOS) were purified from the thermally hydrolyzed mannan in spent coffee grounds, with the aim of achieving the full utilization of natural unused food material. The effects of MOS on fecal microflora and the defecating conditions in eight healthy volunteers were investigated. The subjects were administered MOS at 1.0 g/day and 3.0 g/day for 2 weeks. A 2 week interval was observed between the two dose intake periods. The content of Bifidobacterium significantly increased during the two periods (p < 0.05). It appeared that MOS intake had a tendency to increase the content of Bifidobacterium in fecal microflora depending on the dosage level. Defecating conditions were also improved at both dosage levels (p < 0.05). These results suggested that MOS ingestion caused Bifido-bacterium to be the predominant bacteria in the intestine and improved defecation.
The XTT (3′-[1-(phenylamino)-carbonyl]-3,4-tetrazolium)-bis(4-methoxy-6-nitro)benzenesulfonic acid hydrate) reducibility of practical milk sample enables evaluation of the heat-treatment and storage conditions such as temperature and period. Based on the appearance of absorption maximum at 320 nm in a model heated solution, we suggested that aminoreductone formed during the Maillard reaction of lactose is involved in the reduction of XTT. In this report, the relationship between the XTT reducibility and the formation of aminoreductone was investigated more specifically using HPLC equipped with a photodiode array detector. Lactose and butylamine were heated at 100°C for 15 min, and then analyzed by HPLC. A main peak with absorption maximum at 324 nm, which is thought to be aminoreductone, was recognized in the chromatogram of the heated reaction mixture. The peak corresponding to aminoreductone showed the XTT reducibility. After the addition of Cu2, the main peak and its ability to reduce XTT completely disappeared. Moreover, the formation of aminoreductone under various kinds of heating conditions linearly related with the XTT reducibility of the reaction mixture. These findings strongly suggested that the XTT-reducing substance formed during the Maillard reaction of lactose was aminoreductone.
Kuroawabitake (Pleurotus abalonus) were divided into two parts during development of fruit body: coremia (black-headed coremioid) and fruit body. The proximate compositions and free amino acids were determined. There was no marked difference between the coremia and fruit body in proximate composition of protein and carbohydrate (dry weight). The fruit body was high in moisture and fat, whereas the ash was high in coremia. The fruit body contained higher amounts of total free amino acids than the coremia. The contents of monosodium glutamate-like components, including aspartic and glutamic acids, were high in fruit body, and the two parts were considerably different tasting in their amino acids.
Seven triterpenes, α-amyrin (1), uvaol (2), ursolic acid (3), β-amyrin (4), erythrodiol (5), lupeol (6) and betulin (7), two sterols, β-sitosterol (8) and β-sitosterol 3-O-β-glucopyranoside (9), and one flavonoid, syringetin 3-O-α-rhamnopyranoside (10) were isolated from the methanol extract of the fruit of rabbiteye blueberry (Vaccinium ashei). Their chemical structures were determined on the basis of spectroscopic data. Among them, 3, 4 and 9 exhibited moderate growth inhibitory activity against human lung cancer cells (PC-12) and human colon cancer cells (HCT116) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.