Effects of dried natto diet on the transcript levels of the peroxisome proliferator-activated receptor-γ, coactivator-1α and -1ß, and nuclear receptor corepressor 1 genes in laying hens.

The effects of natto, a fermented soybean food, on transcript levels of hen peroxisome proliferator-activated receptor-γ (PPARG), PPARG coactivator-1α and -1ß (PPARGC1A and PPARGC1B), and nuclear receptor corepressor 1 (NCOR1) were investigated using real-time polymerase chain reaction in white leghorn (Julia strain) hens. Twenty-one- and 34-week-old hens were fed a basic or 3% dried natto-supplemented diet for 8 weeks. In the 21- and 34-week-old hens fed the natto-supplemented diet, hepatic PPARGC1B and NCOR1 transcript levels and adipose and hepatic PPARG transcript levels were significantly lower, respectively, than those in the control group. Furthermore, 34- and 42-week-old hens were fed a basic diet supplemented with 3% of the protein/fiber-enriched fraction (PFB) or 0.6% of the fat-enriched fraction (FAT) of natto, respectively, for 8 weeks. Adipose PPARG transcript levels were higher in the FAT diet group and significantly lower in the PFB diet group than in the control group. However, both FAT and PFB diet groups showed significantly lower hepatic PPARG transcript levels than did the control group. These results suggest that dried natto influences the transcript levels of PPARG, PPARGC1B, and NCOR1, and the FAT and PFB of natto influence the adipose and hepatic PPARG transcript levels in hens.

Metabolomic analyses of plasma and liver of mice fed with immature Citrus tumida peel.

In this study, we investigated the effects of dietary supplementation of Citrus tumida hort. ex Tanaka on food intake, body and fat tissue weights, and metabolic profiles of plasma and liver in mice. Supplementation with 5% (w/w) of peels of immature C. tumida (PIC) for 4 weeks significantly suppressed body weight gain and decreased adipose tissue weight in epididymal, perirenal, and subcutaneous fats. Metabolome analyses showed that 2-hydroxyvaleric acid levels were reduced in the blood plasma of mice fed with PIC. PIC supplementation significantly elevated dipeptide (Thr-Asp, Ser-Glu, and Ala-Ala), glucuronic acid, and S-methylglutathione levels, and significantly reduced betaine aldehyde levels in the liver. In conclusion, PIC supplementation affects the metabolism of fatty acids, pectin, glutathione, and choline, showing potential beneficial effects for metabolic syndrome and obesity. PIC may be developed as a functional food and used in the treatment of these diseases.

Dietary intake of the citrus flavonoid hesperidin affects stress-resilience and brain kynurenine levels in a subchronic and mild social defeat stress model in mice.

Depressive disorders are partly caused by chronic inflammation through the kynurenine (KYN) pathway. Preventive intervention using anti-inflammatory reagents may be beneficial for alleviating the risk of depression. In this study, we focused on the Japanese local citrus plant, Citrus tumida hort. ex Tanaka (C. tumida; CT), which contains flavonoids such as hesperidin that have anti-inflammatory actions. The dietary intake of 5% immature peels of CT fruits slightly increased stress resilience in a subchronic and mild social defeat (sCSDS) model in mice. Moreover, the dietary intake of 0.1% hesperidin significantly increased stress resilience and suppressed KYN levels in the hippocampus and prefrontal cortex in these mice. In addition, KYN levels in the hippocampus and prefrontal cortex were significantly correlated with the susceptibility to stress. In conclusion, these results suggest that dietary hesperidin increases stress resilience by suppressing the augmentation of KYN signaling under sCSDS.

Dietary Intake of Immature Citrus tumida Hort. ex Tanaka Peels Suppressed Body Weight Gain and Fat Accumulation in a Mouse Model of Acute Obesity.

Citrus fruits have several potential benefits for maintaining our health. In this study, we investigated the anti-obesity effects of immature Citrus tumida hort. ex Tanaka (C. tumida) peels using an acute obesity mice model. C57BL/6J male mice were divided into 2 groups; HFD-LL subjected to a high fat diet (HFD) and constant light exposure (LL), and HFDC-LL subjected to a HFD containing immature peel powder of C. tumida (5% w/w) and LL. Dietary ingestion of immature C. tumida peels significantly suppressed body weight gain following decreased epidydimal, perirenal, and subcutaneous fat weights. Blood levels of triglyceride and total cholesterol in the HFDC-LL were significantly lower than those in the HFD-LL group; however, there was no significant difference in food or calorie intake between the 2 groups. These results suggested that immature C. tumida peels have a beneficial effect on the prevention of obesity and metabolic syndrome via its biochemical activities of lipid metabolism.

Effects of combined treatment with fermented soybean (natto) intake and exercise on bone metabolism in ovariectomized rats.

OBJECTIVES: Using ovariectomized rats, we examined the influence of combined exercise tolerance and natto intake on the bone loss inhibitory effect. METHODS: We divided female Wistar rats into the following groups: Ovariectomy, Ovariectomy + Exercise, Ovariectomy + Natto Intake, Ovariectomy + Exercise + Natto Intake, and Pseudo-operative (Sham group). After conducting experiments on each group, we collected the tissues and performed morphological and molecular biological analyses. RESULTS: In comparison with the Ovariectomy group, only in the Ovariectomy + Exercise group was there a significant bone loss inhibitory effect in the femoral cancellous bone. Although there was a tendency toward this trend seen in the Natto Intake and Exercise + Natto Intake groups, these differences were not significant. The increase in messenger RNA expression levels of alkaline phosphatase (osteoblast marker) in the bone marrow caused by ovariectomy was suppressed by individual factors, and by those in combination. However, messenger RNA expression levels of estrogen receptor alpha in the bone marrow showed a decreasing tendency with each factor, and decreased significantly with the combination, similar to the Sham group. CONCLUSION: This suggests that natto intake and exercise maintain bone mass by different molecular mechanisms and that these two factors do not simply act synergistically in combination to maintain bone mass.

Evaluation of the thermal property of bovine intramuscular adipose tissue using differential scanning calorimetry.

The thermal property of bovine intramuscular adipose tissue (IAT) was evaluated using differential scanning calorimetry (DSC) and compared with the melting point temperature (MP) of the fat extract of IAT, which was measured using the slip point method. The beef samples were classified according to the beef marbling score (BMS). Beef with a high BMS contained less protein than that with middle or low BMS. Beef with a high BMS contained significantly more fat than that with a low BMS (P < 0.05). The endothermic point temperature (EP) of IAT, measured by DSC, was significantly higher than the MP of IAT fat (P < 0.05). The EP showed no significant difference among the three marbling grade groups. Although the MP was correlated with the monounsaturated fatty acids (MUFA) content of IAT (R2  = 0.505), there was no correlation between the EP and the MUFA (R2  = 0.040). However, the EP of IAT treated with collagenase was relatively highly correlated with the MP (R2  = 0.655). Thus, these results suggested that DSC analysis would give us the practical thermal information regarding the melt-in the-mouth of beef such as the gelatinization of collagen, along with the melting of fat in IAT.

Characterization and classification of Japanese consumer perceptions for beef tenderness using descriptive texture characteristics assessed by a trained sensory panel.

Meat tenderness is an important characteristic in terms of consumer preference and satisfaction. However, each consumer may have his/her own criteria to judge meat tenderness, because consumers are neither selected nor trained like an expert sensory panel. This study aimed to characterize consumer tenderness using descriptive texture profiles such as chewiness and hardness assessed by a trained panel. Longissimus muscles cooked at four different end-point temperatures were subjected to a trained sensory panel (n=18) and consumer (n=107) tenderness tests. Multiple regression analysis showed that consumer tenderness was characterized as 'low-chewiness and low hardness texture.' Subsequently, consumers were divided into two groups by cluster analysis according to tenderness perceptions in each participant, and the two groups were characterized as 'tenderness is mainly low-chewiness' and 'tenderness is mainly low-hardness' for tenderness perception, respectively. These results demonstrate objective characteristics and variability of consumer meat tenderness, and provide new information regarding the evaluation and management of meat tenderness for meat manufacturers.

Simple method for isolation of glyceraldehyde 3-phosphate dehydrogenase and the improvement of myofibril gel properties.

Porcine glycolytic enzyme, glyceraldehyde 3-phosphate dehydrogenase (G3PD) was prepared effectively by a combination of ethylene diamine tetra-acetate (EDTA) pretreatment and affinity purification. After salting out of porcine sarcoplasmic proteins (SP) with ammonium sulfate at 75% saturation, the obtained supernatant (SP-f3) was treated with EDTA, leaving G3PD in the supernatant (G3PD-E) and most other SPs in the precipitate. At that time, the separation of G3PD-E required more than 20 mmol/L EDTA. G3PD-E was then subjected to affinity purification by batchwise method using blue-sepharose CL-6B, and purified G3PD (G3PD-AP) was obtained using 2 mol/L potassium chloride (KCl) as an eluent. Texture analysis showed that the hardness, adhesiveness and gumminess of the myofibril gel at 0.2-mol/L NaCl increased with the addition of G3PD-AP. Scanning electron microscopy revealed that the G3PD-AP reinforced the gel network of the myofibril. However, scanning electron micrograph analysis showed that the network-structure of the gel by the addition of G3PD-AP developed in a different manner from that by adding 0.6 mol/L NaCl. These results showed that glycolytic enzyme, G3PD, contributes to the improvement of the rheological properties of meat products.

Determination of short-chain fatty acids in rat and human feces by high-performance liquid chromatography with electrochemical detection.

A simple method for determining short-chain fatty acids (SCFAs) in rat and human feces was developed using high-performance liquid chromatography with electrochemical detection (HPLC-ECD). A two-channel HPLC-ECD system was fabricated using an ion exclusion column and an electrochemical detector with a glassy carbon working electrode. Aqueous solutions of 0.1 mM HClO(4) and of ethanol containing 2-methyl-1,4-naphthoquinone served as a mobile phase and a quinone solution, respectively. Peak areas for lactic, acetic, propionic, butyric, isovaleric, and valeric acids at a detection potential of -0.9 V vs. an Ag/AgCl electrode showed a linear relationship with the acid amount in the range 0.1 to 40 nmol. Standard acids at 4 nmol were determined ten times with relative standard deviations (RSD) of less than 2.0%. The analytical results of healthy human feces were measured within 35 min. RSD (n = 5) in all SCFAs were less than 2.7%, and recoveries of SCFAs were more than 92%. The present method was characterized by reproducibility with the simple and rapid procedure without derivatization of analytes, and it has the potential for clinical and biomedical applications.

Purification and identification of a ACE inhibitory peptide from oyster proteins hydrolysate and the antihypertensive effect of hydrolysate in spontaneously hypertensive rats.

Oyster (Crassostrea talienwhanensis Crosse) proteins were produced from fresh oyster and subsequently digested with pepsin. The separations were performed with a Sephadex LH-20 gel filtration chromatography and a RP-HPLC. A purified peptide with sequence Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe (VVYPWTQRF) was firstly isolated and characterized from oyster protein hydrolysate and its ACE inhibitory activity was determined with IC50 value of 66µmol/L in vitro. Stability study for ACE inhibitory activity showed that the isolated nonapeptide had the good heat and pH stability and strong enzyme-resistant properties against gastrointestinal proteases. Kinetic experiments demonstrated that inhibitory kinetic mechanism of this peptide was non-competitive and its Km and Ki values were calculated. The yield of this peptide from oyster proteins was 8.5%. Furthermore, the oyster protein hydrolysate (fraction II), prepared by pepsin treatment firstly exhibited antihypertensive activity when it was orally administered to spontaneously hypertensive rat (SHR) at a dose of 20mg/kg. These results demonstrated that the hydrolysate from oyster proteins prepared by pepsin treatment could serve as a source of peptides with antihypertensive activity.

Isolation and characterization of angiotensin I-converting enzyme inhibitory peptides derived from porcine hemoglobin.

Animal blood is potentially an untapped source of drugs and value-added food production. More than 400 million pigs are slaughtered each year but porcine blood is usually discarded in China. This study describes the isolation and characterization of angiotensin I-converting enzyme (ACE) inhibitory peptides derived from porcine hemoglobin. The most active hydrolysate was obtained from the peptic digestion of porcine hemoglobin. After the purification of ACE-inhibitory peptides with Sephadex LH-20 gel chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC) on C(18) column, two active fractions were obtained. They were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). They were LGFPTTKTYFPHF and VVYPWT, corresponding to the 34-46 fragment of the alpha chain and the 34-39 fragment of the beta chain of porcine hemoglobin, with IC(50) values of 4.92 and 6.02 microM, respectively. They were the first found from porcine hemoglobin; in particular, LGFPTTKTYFPHF was a novel ACE-inhibitory peptide. In addition, the purified ACE inhibitors both competitively inhibited ACE, and maintained inhibitory activity even after incubation with gastrointestinal proteases. This suggests that these peptides might have a potential antihypertensive effect.

Determination of organic acids by high-performance liquid chromatography with electrochemical detection during wine brewing.

Voltammetric determination of acids by means of the electrochemical reduction of quinone was applied to high-performance liquid chromatography (HPLC) with electrochemical detection (ED) for determining organic acids in fruit wines. A two-channel HPLC-ED system was fabricated by use of an ion-exclusion column and an electrochemical detector with a glassy carbon working electrode. Aqueous solution of 0.1 mM HClO(4) and ethanol containing 2-methyl-1,4-naphthoquinone served as a mobile phase and reagent solution, respectively. Determination of acetic, citric, lactic, malic, succinic, and tartaric acids was made by measuring the peak areas of the flow signals due to the reduction current of quinone caused by the eluted acids. The peak area was found to be linearly related to the acid amount ranging from 0.1 to 40 nmol per 20 microL injection. The present method was characterized by reproducibility with the simple and rapid procedure without derivatization of analytes. The method was shown as an effective means for following acid contents in fruit juices during fermentation with wine yeast.

A disposable voltammetric cell for determining the titratable acidity in vinegar.

A disposable voltammetric cell using three pencil leads as working, reference, and counter electrodes was developed for determining the titratable acidity, i.e. the acid content in vinegar. The materials of the pencil leads were graphite-reinforcement carbons (GRCs). A voltammetric determination of acid was made by measuring the reduction prepeak current of 3,5-di-t-butyl-1,2-benzoquinone (DBBQ) due to the presence of acids in unbuffered solution. The potential stability of the pseudo-reference electrode of GRC was examined. The prepeak current was found to be proportional to the acetic acid concentration from 0.05 to 2.7 mM with a correlation coefficient of 0.999. The cell-to-cell reproducibility for 1 mM acetic acid was evaluated with ten individual disposable cells. The RSD of the prepeak current and the SD of the prepeak potential were 2.56% and 0.008, respectively. The titratable acidity in five vinegar samples was determined by voltammetry using disposable cells and compared with that of the titratable acidity determined by the conventional potentiometric titration method. We then observed the results by both methods, and found a correlation coefficient of 0.972. As such, the voltammetry using disposable-cell required only one thousandth the volume of a vinegar sample for the titration method. The disposable cell was superior to the conventional electrochemical cell, in terms of facility, environment-friendly, and economy, and thus a sensor using the present cell would be useful for routine work in the quality control of vinegar.