The purpose of this study was to develop sprouted brown rice (SBR), where germinated brown rice (GBR) is cultivated until the shoot and first leaf emerge. SBR is a combination of GBR, which contains high levels of GABA, and sprouts, which are known for their chemopreventive effects. This study showed that SBR with intact grains and almost no roots can be grown by anaerobic water cultivation using weakly acidic electrolyzed water. Amino acids in SBR, which are associated with secondary and tertiary functions, and phenols reached maximum contents after 14–19 and 7 days of culture, respectively, and GABA content (134 mg /100 g dw) was higher than that previously reported in GBR. In addition, the viable cell count of fresh SBR after washing satisfied conditions for raw consumption. SBR has high potential as a novel approach to consuming brown rice with enhanced functionality.
This study performed a kinetic analysis of the oxidation of partially oxidized linoleic acids to understand the oxidation process under practical conditions. In these experiments, lipid was spotted on the bottoms of test tubes, which were then held in a water bath at 50 °C for 0, 1, or 2 h to obtain controlled partially oxidized lipid. The test tubes were then stored at 5 °C for 6 days in the dark. The conjugated diene structure of the primary oxidation products was measured to evaluate the progress of autoxidation of the lipid by spectrophotometry. The oxidation processes of linoleic acid at 5 °C after the storage period at 50 °C differed among samples and could not be explained without the effect of accumulated primary oxidation products at the start of oxidation at 5 °C. These oxidation processes were described by a square root autoxidation model.
The sorption isotherms and diffusion coefficients of glucose and sodium chloride on konjac and egg white gel were measured at temperatures ranging from 4 °C to 80 °C to systematically organize the transport of seasoning compounds during food manufacturing. The distribution coefficients, defined as the slopes of the sorption isotherms, decreased as the temperature increased. The enthalpy changes calculated from the temperature dependence of the distribution coefficients for glucose and sodium chloride on konjac and egg white gel were approximately −2 kJ/mol. The effective diffusion coefficients ranged from 10−10 to 10−8 m2/s and increased with the temperature. The activation energies of diffusion in konjac and egg white gel were approximately 17 and 9 kJ/mol, respectively; glucose and sodium chloride had similar activation energies for diffusion. Diffusion in multi-component systems was also studied; the degrees of sorption in multi-component systems differed from those in single-component systems.
We examined the effect of taro drying processes on the properties of taro flour and taro flour products. Taro flour produced by blast-drying with hot air was characterized by the formation of aggregated starch granules during storage. Consequently, pastes made from blast-dried flour exhibited higher hardness and adhesiveness than pastes made from fresh taro. Pastes made from freeze-dried flour exhibited similar increases in hardness and adhesiveness due to the formation of aggregated starch granules during heating. Starch granules did not aggregate in flour that was blast-dried after heating, and the hardness and adhesiveness of pastes were lower than those of fresh taro. Bread substituted with 10 % blast-dried flour after heating exhibited softening and increased cohesiveness. The results demonstrated that the drying processes of taro flour have a marked effect on the texture of products by affecting the aggregation and swelling of starch granules.
The majority of dairy cows in Japan are Holstein cows. Milk items containing only milk from Jersey cows are sold at a premium price. Therefore, it is important to keep Holstein milk from contaminating the milk labeled as pure Jersey milk to maintain brand value. Here, genetic testing was conducted on packaged milk items. Polymorphisms of the melanocortin-1 receptor (MC1R) gene, which controls variations in coat color, were assayed in addition to the frequencies of MC1R alleles in Holstein and Jersey cows in Japan. In Holstein cows, the frequency of the ED allele was 0.876, but this allele is absent in Jersey cows. Thus, detection of the ED allele clearly indicates the presence of Holstein DNA. This DNA-based test was also useful in testing sterilized milk products. The results of the DNA-based test show that pure Jersey milk can be easily distinguished from Holstein milk.
The leavening of gluten-free rice flour bread is enhanced when soymilk is used instead of water. However, as the amount of batter is increased to bake bread in the shape of a square, the crumb becomes less dense. This study aimed to investigate the effects of hydrocolloids (xanthan, guar, curdlan, methylcellulose, and hydroxypropyl methylcellulose) on crumb hollowing. When 0.5 % methylcellulose or hydroxypropyl methylcellulose was added to gluten-free bread made with soymilk, the crumb could be baked without hollowing. The addition of 1 % or more of cellulose derivatives is needed to ensure satisfactory leavening of gluten-free bread. By combining cellulose derivatives with soymilk, a homogeneous crumb structure could be achieved with the addition of 0.5 % of cellulose derivatives. These results suggest that cellulose derivatives are effective for preventing bread from losing density, as they contribute to bubble stabilization via their interfacial activity and promote superior viscosity.
Desirable bright cherry-red meat color of tuna depends on the redox state of myoglobin (Mb). Mitochondria involved in energy production in live muscle, also influence the redox state. However, no research has determined metmyoglobin (metMb) reduction in tuna muscle via mitochondria. This study aimed to assess the metMb reductase activity in the mitochondrial fraction from the dark muscle of tuna with a high concentration of Mb. As a result, elevated assay temperature resulted in increasing mitochondrial metMb reductase activity in the range of 10–30 °C. There was no significant change in the activity between pH 5.7–6.8, but a significant decrease was observed at pH 7.0. Furthermore, NADH, as the cofactor, was found to initiate the metMb reduction, while exhaustion of NADH resulted in metMb formation. Therefore, maintenance of NADH concentration was considered to be essential to maintain the color of tuna meat during chilled storage.
In this study, the dynamics of the microbial communities and metabolites for soy sauce were investigated. The succession of microbiota was divided into three phases in process. Dynamics of physicochemical properties coincided with the succession of dominant genera in the first 3 months, hereafter changed slightly. The contents of L-malic acid, pyroglutamic acid, and lactic acid were increased by 11.79, 11.39, and 3.19 times (p < 0.05), respectively, compared with that in the initial moromi. The contents of volatiles were changed in the later phase significantly, and dominant constituents were positive correlated with the dominant genera. The ethyl carbamate (EC) and seven kinds of biogenic amines (BAs) reached the maximum in the third month, then their contents decreased. The EC forming involved in two phases, the metabolic pathway was partly shared with that of putrescine biosynthesis. These results laid an important foundation in reducing the endogenous hazards by bioturbating.
Japanese sake is manufactured via the moromi (fermentation mash)-filtration process using filter cloths. We measured volatile compounds accumulated in used filter cloths and detected many esters, including fatty acid ethyl esters (FAEEs), suggesting that filter cloths adsorb esters from sake. The profile of volatile compounds trapped in filter cloths differed depending on the material. Moreover, we demonstrated that medium and long-chain FAEEs, but not fatty acids (FAs), were decreased in the initial period of practical automatic pressing. These results indicated that medium and long-chain FAEEs are likely to be adsorbed to filter cloths made of polyethylene terephthalate, which is generally used in automatic pressing. The ratio of FAs to FAEEs with 8 and 10 carbons increased after automatic pressing. This is possibly one reason why organoleptic properties are changed after moromi-filtration.
Flos Dolichoris Lablab, as a flower of a homologous plant with medicinal and food applications, has rich plant activity with research value. In this article, we studied flavonoids in Flos Dolichoris Lablab, and an effective semipreparative HPLC separation method was established. Then, seven flavonoids from Flos Dolichoris Lablab were prepared in one step, and their antioxidant activity was evaluated. The results show for the first time that the seven flavonoids kaempferol 3-O-sophoroside (1), quercetin 3-rutinoside (2), quercetin 3-glucoside (3), kaempferol-3-O-robinobioside (4), kaempferol-3-O-rutinoside (5), isorhamnetin 3-O-neohesperidoside (6), and kaempferol-3-O-galactoside (7) were isolated from the genus Lablab. Antioxidant activity results with individual compounds show that compounds 2, 3, and 7 exhibit better antioxidant activity. Experiments on different combinations of flavonoids of Flos Dolichoris Lablab indicate that the interaction of flavonoids can affect the mixture's total antioxidant activity. This research provides guidelines for preparing flavonoids present in Flos Dolichoris Lablab and structure-activity relationship studies.
A novel peptide PYPYEPYEPYPY from Yak bone hydrolysate (YBG) was purified by Sephadex G-25, RP-HPLC and identified by ESI-TOF-MS. The peptide exhibited some antioxidant activity in HepG2 cells and the dipeptidyl peptidase IV (DPP-IV) inhibition activities in vivo. In HepG2 cells, when the concentration of peptide was 20–160 µM, it could increase the half-lethal rate (LD50) of cells and showed cytoprotective effect, while at 20–40 µM reduced the reactive oxygen species (ROS) content. The peptide PYPYEPYEPYPY exhibited the highest DPP-IV inhibition activities with IC50 value of 189.4 µM among the nine peptides from YBG. Molecular docking predicted the interaction of peptide PYPYEPYEPYPY with DPP-IV residues TRP62, THR304 and SER462, and the binding between them mainly depends on van der Waals forces and hydrogen bonds. Glucose tolerance tests were performed on C57 mice orally administered synthesized PYPYEPYEPYPY. The maximal decrement in the blood glucose was 10.28 ± 0.47 mmol/L induced by one-time gavage of PYPYEPYEPYPY at 100 mg/kg. This is the first report that both DPP-IV inhibitory activity and antioxidant activity have been identified from yak bone hydrolysate.
β-Linked water soluble polysaccharides are important bioactive components of mushrooms and plants, they possess various biological activities, such as anti-inflammation, immunomodulation, anti-tumor and others. This study aimed to examine the comparative anti-inflammatory effects of five different β-linked water soluble polysaccharides from fungi and plants [i.e. Xylaria nigripes (XN), Grifola frondosa (GF), Lentinula lentodes (Len), Laminaria digitata (Lam) and Hordeum vulgare (BG)] in lipopolysaccharides-stimulated RAW264.7 macrophages. Although the selected five polysaccharides showed different potencies in anti-inflammatory activity, XN exhibited the strongest inhibitory effects on NO, TNF-α and IL-6 production, and iNOS and COX-2 expression, whereas the inhibitory activity of BG was the weakest. Among the polysaccharides with β-(1→3, 1→6) glucose linkages and triple-helix structures, the inhibition of GF and Len on TNF-α and IL-6 production was weaker than XN and Lam. This study concludes that the monosaccharide composition, glycosidic linkage and tertiary conformation were the main factors affecting the anti-inflammatory activity of polysaccharides, and polysaccharides with β-(1→3, 1→6) glycosidic linkages possessed stronger anti-inflammatory activity than β-(1→3, 1→4)-linked polysaccharides.
Poly-gamma-glutamic acid (γ-PGA) is a major constituent of the fermented soybean product “natto”. We developed a high-accuracy method for quantifying γ-PGA content in natto rich in γ-PGA by lyophilizing and powdering the natto and optimizing protein and peptide removal, ethanol precipitation, degradation by hydrochloric acid, and quantification as glutamic acid using high-performance liquid chromatography. In this method, protein and peptide contaminants were removed from natto samples by trichloroacetic acid precipitation. The γ-PGA content of both γ-PGA-rich and γ-PGA-poor natto was measurable using this method. A single-laboratory validation test showed a repeatability relative standard deviation of 1.9 %–4.3 % and intermediate relative standard deviation of 1.8 %–3.9 %. The recovery of γ-PGA from natto samples spiked with three different amounts of γ-PGA was 98.5 %–101.0 %. These results show that our developed method has high accuracy and repeatability. Therefore, this method serves as a practical quantification protocol for determining the γ-PGA content of natto.
The current study aimed to investigate the apoptotic and anti-proliferative effect of essential oils obtained from turmeric (Curcuma longa L.) at cellular level. To test the effects and mechanism, H1299 and HepG2 cells were selected for in vitro experiments. Cytotoxicity assay and morphology of cells analyses were performed to estimate the effect of turmeric essential oil (TEO) on the viability and cell growth. Proapoptotic and anti-proliferative effects of TEO were investigated using flow cytometry. Subsequent experiments assessed cell migration and colony formation of cells to evaluate the anti-metastatic effects of TEO by in vitro wound-healing assays and colony formation assays. The results indicated that treatment with more than 50 mg/L TEO for 48 h could significantly inhibit the proliferation of H1299 and HepG2 cells and could significantly inhibit cell migration and colony formation of cells (p < 0.05).
The yeast strain Hanseniaspora vineae TW15 derived from local wine grapes lacks sucrose fermentation ability, confers palatable aroma and taste in breads made from dough with monosaccharides added instead of sucrose. In this study, strain TW15 was applied along with the baking strain Saccharomyces cerevisiae to the conventional dough containing sucrose. The liquid fermentation ability of sucrose was elevated with the increasing ratio of S. cerevisiae, which synthesizes external invertase. The baking strain was then inoculated along with H. vineae TW15 and the two strains were grown on sucrose. When the mixed cells were used for the conventional dough formula comprising sucrose, the baked breads showed a distinct and acceptable quality similar to those made using H. vineae TW15 alone. Thus, H. vineae TW15 can be applied to the conventional bread making method in mixed culture with a baking strain.
In this study, we investigated the role of ovalbumin (OVA), ovotransferrin (OVT), and lysozyme (LYZ) as the major proteins involved in heat-induced gelation of egg white. OVT and LYZ deficient egg white (OLdEW) solutions were prepared from raw egg white (REW) subjected to heat treatment at 64 °C and centrifugation. OLdEW had almost the same native-OVA protein as in REW, confirmed by gel electrophoresis, differential scanning calorimetry, and surface hydrophobicity measurement. Texture profile analysis, syneresis rate measurement, and observation by scanning electron microscopy were performed for the heat-induced gels. The OLdEW gel had more porous and fibrous networks, resulting in less hardness, more resilience and compatible water holding capacity compared to the REW gel. These results suggest that OVA contributes to the water holding capacity and resilience in egg white gel, while OVT and LYZ contribute to enhanced gel hardness.
Storage conditions significantly affect the quality of natto, a fermented soybean food produced with Bacillus subtilis (natto). We investigated the relationship between the quality of natto and the storage temperature. Manufactured natto samples were stored at 5–20 °C for 20 days, and on every 5th day we evaluated the following: 1) viable bacterial number, 2) ammonia nitrogen, 3) free amino acids, 4) gamma-polyglutamic acid (γ-PGA), 5) hardness, and 6) color of soybean grains. During storage, natto products exhibited damage, especially when stored at 20 °C. Natto products were scored based on these quality indicators, and natto stored at 5 °C for 10 days or at 10 °C for 5 days had similar quality scores. Overseas export of natto is gradually increasing. The quality score proposed in this study is a basic indicator that can be used to rule out inferior products, and this will help to grow the natto market worldwide and facilitate distribution through a cold chain.
This study aimed to use an existing ligand (imidazole)-assisted 1H-nuclear magnetic resonance (1H-NMR) spectroscopy protocol to determine sulfate content of seaweed sulfated saccharides. Twenty seaweed samples – spanning nine species and multiple geographic locations – were analyzed. Extracts were obtained by immersing freeze-dried seaweeds in boiling water, followed by alginate precipitation. Remaining supernatants contained natural crude polysaccharide (CP) fraction, including sulfated polysaccharides. To eliminate free CP carboxy groups that can interfere with the complex formation of imidazole with CP sulfate groups, the carboxy groups were chemically reduced to hydroxymethyl groups prior to 1H-NMR spectroscopy. Resultant sulfate content estimates were comparable to those obtained via a conventional barium-rhodizonate assay. Findings indicate that the imidazole-assisted 1H-NMR spectroscopy is an appropriate method for estimation of seaweed CP sulfate content.
Oleanolic acid (OA), a natural triterpenoid found in various edible plants possessing anti-adiposity and antioxidative activities, could be exploited against obesity, a serious global public health problem. To confirm these properties of OA and understand the underlying mechanisms, this study investigated its effects on lipolysis and antioxidative activities in 3T3-L1 adipocytes. The results demonstrated that OA stimulated lipolysis and phosphorylation of hormone-sensitive lipase (HSL) in 3T3-L1 adipocytes, which was blunted by a PKA inhibitor H-89. In addition, OA induced the expression of heme oxygenase-1 (HO-1) and reduced intracellular oxidative stress. HO-1 inhibitor treatment suppressed the antioxidative effect of OA but did not affect its lipolytic activity. These results indicate that OA exerts lipolytic activity through the PKA pathway and possesses antioxidative properties. These findings suggest the potential of OA as a useful candidate for the treatment of obesity and its related oxidative stress.
To determine the effective use of ‘lemon juice squeezed residue’ (LJSR), which contains many functional ingredients, we administered a diet containing 5% LJSR to spontaneously hypertensive rats (SHR) and investigated its hypotensive and oxidative stress-reducing effects. The flavonoid and coumarin contents of LJSR were measured: hesperidin, eriocitrin, and auraptene were detected. Increased systolic blood pressure was gradually reduced in the LJSR-treated group (LJSR group) and was significantly lower when compared with the control group at 4, 6, 8, 10, and 12 weeks. The urinary levels of 8-hydroxy-2′-deoxyguanosine and isoprostane were significantly lower in the LJSR group compared with the control group. The antioxidant activities of LJSR are associated with the actions of flavonoids and coumarin, which act as radical scavengers. These results suggest that LJSR could be used commercially as an antihypertensive food.
In this study, we analyzed the different parts of mushrooms using electron spin resonance (ESR) to identify radical species, and we examined their hydroxyl radical scavenging activities. The four kinds of mushrooms investigated in this study, Agrocybe cylindracea (Shakkiko1 and Shakkiko2), Grifola gargal, and Coprinus comatus were separated into caps, stipes, and bases of stipes. ESR spectra of all specimens consisted of signals originating from organic free radicals, Fe3+, Mn2+, and Cu2+ species. The cap showed the highest Fe content. The different mushroom body parts revealed different hydroxyl radical scavenging activity values, among which the C. comatus stipes were the highest. The radical scavenging activities of the evaluated specimens did not correlate with the Fe contents; however, a positive correlation with the Cu contents was observed.
Our previous study indicated that the water-soluble extract obtained from commercially available natto products inhibited the sucrose-dependent cariogenic biofilm formation of Streptococcus mutans. This inhibitory effect correlated with the protease activity levels of the extract. Subtilisin NAT (nattokinase), a subtilisin-like serine protease, is a dominant protease found in natto products. In this study, we investigated the effect of natto products produced by a subtilisin NAT-deficient mutant (aprN−) of the Bacillus subtilis strain NBRC16449 on S. mutans biofilm formation. The mutation decreased the γ-poly glutamic acid (γ-PGA) levels and reduced protease activity in natto products. A significant reduction of the inhibitory effect was observed in the extract from natto products prepared with the aprN− strain. The γ-PGA obtained from the natto products did not affect biofilm formation. We propose that subtilisin NAT plays a major role in biofilm inhibition induced by natto extract.
Koji molds are safe microorganisms belonging to the genus Aspergillus and are used in the production of traditional Japanese fermented foods, such as miso, soy sauce, and sake. Koji molds produce many types of enzymes, including amylase, lipase, and protease, that are used in food processing treatments. To examine the potential of Koji molds for cheese ripening, we measured the lipase and protease activities on cheese curds ripened using five strains of Koji molds (Aspergillus oryzae or A. sojae) and compared them with curds ripened using Penicillium candidum or P. roqueforti. Compared with Penicillium, Koji molds showed similar or higher protease activity on the cheese surface. Lipase activity varied markedly among Koji mold strains; some showed comparable activity to Penicillium, and others showed lower activity. Considering the lipase and protease activities, some Koji molds can be applied to the production of surface mold-ripened cheeses.