Hideki Ushio

High-pressure processing of fish and fish products

Abstract High hydrostatic pressure has recently been applied in food processing, and several commercial fruit and vegetable products have already been put on sale. High hydrostatic pressure results in protein denaturation, resulting in inhibition of some inherent enzymatic activities and of the biogenic activity of some microorganisms. However, high pressure also accelerates lipid oxidation in muscle tissues. Recent intensive research on the effects of high hydrostatic pressure on fish tissues has gradually revealed the benefits and defects of this novel processing technology.

Anti‐inflammatory effects of phytosteryl ferulates in colitis induced by dextran sulphate sodium in mice

We have recently reported that phytosteryl ferulates isolated from rice bran inhibit nuclear factor‐κB (NF‐κB) activity in macrophages. In the present study, we investigated the effect of γ‐oryzanol (γ‐ORZ), a mixture of phytosteryl ferulates, cycloartenyl ferulate (CAF), one of the components of γ‐ORZ, and ferulic acid (FA), a possible metabolite of γ‐ORZ in vivo, on a model of colitis in mice.

Sphingomonas cloacae sp. nov., a nonylphenol-degrading bacterium isolated from wastewater of a sewage-treatment plant in Tokyo

A nonylphenol-assimilating bacterium isolated at a sewage-treatment plant in Tokyo was studied phenotypically, genotypically and phylogenetically. Analysis of the 16S rDNA sequence, the G+C content of the DNA (63 mol%) and the isoprenoid quinone composition, as well as the presence of sphingoglycolipid and the whole-cell fatty acid profile, revealed that the isolate is a member of the genus Sphingomonas. However, the sequence similarity of the 16S rDNA with that of known Sphingomonas spp. was found to be at most 96%, implying that the isolate is distinctive. Furthermore, the results of DNA-DNA hybridization experiments and its physiological characteristics clearly indicated that the isolate represents a new Sphingomonas species, for which the name Sphingomonas cloacae is proposed; strain S-3T (= JCM 10874T = IAM 14885) is the type strain.

Effects of droplet size on the oxidative stability of oil-in-water emulsions.

The effects of droplet size and emulsifiers on oxidative stability of polyunsaturated TAG in oil-in-water (o/w) emulsions with droplet sizes of 0.806±0.0690, 3.28±0.0660, or 10.7±0.106 μm (mean ± SD) were investigated. Hydroperoxide contents in the emulsion with a mean droplet size of 0.831 μm were significantly lower than those in the emulsion with a mean droplet size of 12.8 μm for up to 120 h of oxidation time. Residual oxygen contents in the headspace air of the vials containing an o/w emulsion with a mean droplet size of 0.831 μm were lower compared with those of the emulsion with a mean droplet size of 12.8 μm. Hexanal developed from soybean oil TAG o/w emulsions with smaller droplet size showed significantly lower residual oxygen contents than those of the larger droplet size emulsions. Consequently, oxidative stability of TAG in o/w emulsions could be controlled by the size of oil droplet even though the origins of TAG were different. Spin-spin relaxation time of protons of acyl residues on TAG in o/w emulsions measured by 1H NMR suggested that motional frequency of some acyl residues was shorter in o/w emulsions with a smaller droplet size. The effect of the wedge associated with hydrophobic acyl residues of emulsifiers was proposed as a possible mechanism to explain differences in oxidative stability between o/w emulsions with different droplet sizes.

Toughness and Collagen Content of Abalone Muscles

Toughness and collagen content were measured for various muscle parts of the Japanese abalone, kuro-awabi (Haliotis discus), in relation to muscle structures. The dorsal surface of the foot was toughest, followed by the hard and soft part of the foot, then the upper and middle part of the adductor muscle, irrespective of being reared or wild specimens. When compared with other abalone species, kuro-awabi showed the highest toughness for all the muscle parts, followed by madaka (H. sieboldii) and megai-awabi (H. gigas), while ezo-awabi (H. discus hannai) was softest. Collagen content was parallel with muscle toughness: the higher the collagen content, the tougher the muscle. Light micrographs of kuro-awabi showed that foot and the dorsal surface of foot were dominated by connective tissues, while adductor muscle was mainly composed of myofibrils. Transmission electron micrographs demonstrated that myofibrils in the foot were surrounded by thick layers of collagen fibrils of about 1 μm, confirming light microscopic observations.

The effects of hydroxycinnamic acid derivatives on adiponectin secretion

Adiponectin is positively correlated with insulin sensitivity. Hydroxycinnamic acid derivatives (HADs), observed ubiquitously in plants, have some physiological functions. In this study, we investigated the effect of HADs on serum adiponectin concentrations in mice and on adiponectin secretion of 3T3-L1 adipocytes. In mice, serum adiponectin concentrations were increased by gamma-oryzanol administration. CAPE, curcumin, and trans-ferulic acid markedly enhanced the adiponectin secretion of 3T3-L1 adipocytes, but not gamma-oryzanol. To clarify the effects of gamma-oryzanol in mice or the effects of HADs on the underlying mechanisms of adiponectin secretion, we further investigated the effect of HADs on adiponectin secretion in the NF-kappaB activation state. Although the adiponectin secretion was reduced in the presence of lipopolysaccharide plus TNF-alpha and IFN-gamma, only gamma-oryzanol supported the activity of adiponectin secretion under NF-kappaB activated condition. The results indicate that these HADs might regulate adiponectin secretion by the inhibition of NF-kappaB activation. HADs might be effective for ameliorating type 2 diabetes.

Biological abilities of rice bran-derived antioxidant phytochemicals for medical therapy.

Rice bran contains important bioactive phytochemicals. Among these phytochemicals, steryl ferulates including γ-oryzanol and its major components such as cycloartenyl ferulate (CAF), 24-methylenecycloartanyl ferulate (24-mCAF), β-sitosteryl ferulate (β-SF), and campesteryl ferulate have been intensively studied due to their crucial roles in pathological processes. On the basis of experimental studies published during the last decade in relation to antioxidant, anti-inflammatory, anti-ulcerogenic, hypolipidemic, anti-neoplastic, anti-diabetic, and anti-allergic phenomena, these bioactive phytochemicals are reviewed in this paper. Particularly, in vivo and in vitro studies have clarified that rice bran phytosteryl ferulates mediate anti-inflammatory effects by down-regulating the inflammatory transcription factor, nuclear factor κB (NF-κB), which in turn reduces expression of inflammatory enzymes such as COX-2 and iNOS, and proinflammatory cytokines such as IL-1β, IL-6 and TNF-α. Moreover, rice bran phytosteryl ferulates up-regulate blood adiponectin levels via indirect activation of peroxisomal proliferator-activated receptor γ (PPARγ) through NF-κB inhibition. In this review, we discuss potential pharmacological aspects of rice bran phytosteryl ferulates in the clinical setting.

The effect of trans-ferulic acid and gamma-oryzanol on ethanol-induced liver injury in C57BL mouse

The effects of the oral administration of trans-ferulic acid and gamma-oryzanol (mixture of steryl ferulates) with ethanol (5.0 g per kg) for 30 days to c57BL mice on ethanol-induced liver injury were investigated. Preventions of ethanol-induced liver injury by trans-ferulic acid and gamma-oryzanol were reflected by markedly decreased serum activities of plasma aspartate aminotransferase, alanine aminotransferase and significant decreases in hepatic lipid hydroperoxide and TBARS levels. Furthermore, the trans-ferulic acid- and gamma-oryzanol-treated mice recovered ethanol-induced decrease in hepatic glutathione level together with enhancing superoxide dismutase activity. These results demonstrate that both trans-ferulic acid and gamma-oryzanol exert a protective action on liver injury induced by chronic ethanol ingestion.

Quantitative determination of total lipid hydroperoxides by a flow injection analysis system

A flow injection analysis (FIA) system coupled with a fluorescence detection system using diphenyl-1-pyrenylphosphine (DPPP) was developed as a highly sensitive and reproducible quantitative method of total lipid hydroperoxide analysis. Fluorescence analysis of DPPP oxide generated by the reaction of lipid hydroperoxides with DPPP enabled a quantitative determination of the total amount of lipid hydroperoxides. Use of 1-myristoyl-2-(12-((7-nitro-2-1,3-benzoxadiazol-4-yl)amino) dodecanoyl)-sn-glycero-3-phosphocholine as the internal standard improved the sensitivity and reproducibility of the analysis. Several commercially available edible oils, including soybean oil, rapeseed oil, olive oil, corn oil, canola oil, safflower oil, mixed vegetable oils, cod liver oil, and sardine oil were analyzed by the FIA system for the quantitative determination of total lipid hydroperoxides. The minimal amounts of sample oils required were 50 μg of soybean oil (PV=2.71 meq/kg) and 3 mg of sardine oil (PV=0.38 meq/kg) for a single injection. Thus, sensitivity was sufficient for the detection of a small amount and/or low concentration of hydroperoxides in common edible oils. The recovery of sample oils for the FIA system ranged between 87.2±2.6% and 102±5.1% when PV ranged between 0.38 and 58.8 meq/kg. The CV in the analyses of soybean oil (PV=3.25 meq/kg), cod liver oil (PV=6.71 meq/kg), rapeseed oil (PV=12.3 meq/kg), and sardine oil (PV=63.8 meq/kg) were 4.31, 5.66, 8.27, and 11.2%, respectively, demonstrating sufficient reproducibility of the FIA system for the determination of lipid hydroperoxides. The squared correlation (r2) between the FIA system and the official AOCS iodometric titration method in a linear regression analysis was estimated at 0.9976 within the range of 0.35−77.8 meq/kg of PV (n=42). Thus, the FIA system provided satisfactory detection limits, recovery, and reproducibility. The FIA system was further applied to evaluate changes in the total amounts of lipid hydroperoxides in fish muscle stored on ice.

Effects of ergothioneine from mushrooms (Flammulina velutipes) on melanosis and lipid oxidation of kuruma shrimp (Marsupenaeus japonicus).

The antimelanosic and antioxidative properties of a hot water extract prepared from the fruiting body of the edible mushroom (Flammulina velutipes) were evaluated by dietary supplementation in Kuruma shrimp (Marsupenaeus japonicus) for possible aquaculture application. The extract contained ergothioneine (ERT) at a level of 2.05 mg/mL. A commercial standard of l-ergothioneine (l-ERT) and the mushroom extract showed inhibitory activity against mushroom polyphenoloxidase (PPO). Feeding of the extract had no adverse effects on the immune systems of the shrimp under the present experimental conditions. Supplementation of the extract in the diet significantly suppressed PPO activities in the hemolymphs of the shrimp. Expression of the prophenoloxidase (proPO) gene decreased in the hemocyte of the Kuruma shrimp fed with the mushroom extract. Consequently, development of melanosis was significantly suppressed in the supplement fed shrimp during ice storage. Lipid oxidation was also effectively controlled in the supplement fed group throughout the storage period. In vitro experiments showed that l-ERT effectively inhibited the activation of proPO in the hemocyte lysate supernatant (HLS). The transcript of the proPO gene in the hemocyte showed lower expression in the l-ERT-treated HLS. It was concluded that dietary supplementation of the mushroom extract in shrimp could be a promising approach to control post mortem development of melanosis and lipid oxidation in shrimp muscles.