Comparison of lipid damage during frozen storage and the capacity of the natural antioxidant to retard oxidation of polyunsaturated fatty acids in swordfish muscle were investigated. Swordfish fillets were packaged in low density polyethylene with or without the natural antioxidant and frozen for 12 months at −20°C. In the twelfth month, swordfish packed with natural antioxidant showed a lower lipid hydrolysis than in swordfish control sample. Furthermore, swordfish packed with natural antioxidant showed a lower lipid oxidation (primary and secondary lipid oxidation) than in muscle of swordfish control sample. In fact, the total oxidation observed was lower in the samples packed with natural antioxidant than the control during the frozen storage. The results confirm the efficacy of an active packaging with a natural antioxidant derived from barley husks to slow down the progress of lipid hydrolysis and increase oxidative stability in swordfish muscle.
Microwave-assisted extraction (MAE) technique was employed for the extraction of himematsutake (Agaricus blazei Murrill) polysaccharide (PMAE) and optimized by Box-Behnken design. The optimum conditions were extraction time 29.37 min, microwave power 400 W, extraction temperature 74.64°C and ratio of water to material 32.7:1 with an enhanced yield of 12.35%. Furthermore, PMAE had increased antioxidant activity in various oxidative systems in vitro when compared to polysaccharides extracted by conventional methods. The data obtained clearly showed that MAE is a fine way to extract the polysaccharides in A. blazei Murrill. Further, PMAE may be developed into a functional food as well as potential therapeutic agent.
Samples of red sea bream (Pagrus major), a white-meat fish, were grilled under an infrared heater, and the temperature and color of the sample surface was measured. For the change in color, brightness component L* and two chromatic components a*(from green to red) and b*(from blue to yellow) were measured. As the browning reaction proceeded, L* decreased monotonously and a* and b* varied in a complex way; however, a* and b* were correlated with L*. The browning reaction was treated as a first-order reaction and it was assumed that L* decreased in proportion to the reactive product. The reaction rate constant of the diminution rate of L* was determined to be in agreement with the values obtained from the experiment in which sample temperatures were maintained at a certain level. The estimated values of L*, a*, and b* were in good agreement with experimental values.
Effectiveness of a novel developed sanitizer, stable ozone microbubble-containing water (ozone microbubble water; OMBW), on reducing 13 kinds of bacteria was evaluated in vitro. The effectiveness of dip inoculated Escherichia coli O157:H7 or naturally attached bacteria on four kinds of leafy vegetables was also evaluated. For the purpose of comparison, the effectiveness of gaseous ozone (GO), sodium hypochlorite solution (NaClO) and distilled water (DW) were also evaluated. A 5.0 to 7.4 log reduction of viable cells was observed in an in vitro study. In contrast, a 0.8 to 1.2 or 0.9 to 1.8 log CFU/g reduction in E. coli viable cells was observed after washing with OMBW or NaClO, respectively, for all tested leafy vegetables. No significant difference was observed in the effectiveness of OMBW, ozonated water (OW) and DW. No reduction of viable cells was observed after exposure of leaves to GO. Similar experimental results were observed with the naturally attached bacteria. No difference in color and appearance was observed with DW and other sanitizing treatments. These results suggest that the effectiveness of OMBW in surface decontamination of leafy vegetables is similar to that of OW.
Nagamo (Sargassum horneri) processing residue was extracted using a hot water extraction method at various temperatures and solvent/material ratios and analyzed for total sugar (TS). The extraction characteristics of TS were characterized by Peleg’s model, and the optimum extraction conditions for the Nagamo processing residue were obtained at 85°C at a solvent/material ratio of 5. At experimental temperatures and solvent/material ratios, the TS content increased rapidly for the first 2 h and then reached the equilibrium concentration. Additionally, the antioxidant activity (SOD) of the extraction was 60.8% or higher. Thus, it was concluded that the Nagamo processing residue contains biologically active polysaccharides, which can be obtained by using a transportable 400 L-batch extraction process with hot water.
Sericin is a structural polypetide of silk, consisting of a unique composition of amino acids. The use of sericin as an ingredient for salad dressing was evaluated in an o/w emulsion system with rape oil and vinegar. The low-viscosity sericin from white cocoon showed poor emulsifying activity, whereas non-separable dressing with a low peroxide value (POV) could be produced by the addition of high-viscosity sericin. The use of colored sericin, prepared from yellow-green cocoon shell, maintained a relatively low POV in spite of low viscosity and emulsifying activity levels. Total content of flavonol aglycons in yellow-green sericin was quantified after acid hydrolysis, showing that relatively high amounts of quercetin and kaempferol were detected in the colored sericin.
Nonspecific lipid transfer protein 1 (nsLTP1) is widely distributed in plants and has been recognized as a widely cross-reacting plant pan-allergen. In the present study, a recombinant protein of rice nsLTP1 was prepared with an Escherichia coli expression system, and polyclonal antiserum was raised by immunizing rabbits with this recombinant nsLTP1. The antiserum specifically immunoreacted with rice nsLTP1 and homologous nsLTP1 proteins of other kinds of cereal grains. Moreover, the antiserum was applied to compare nsLTP1 content among rice cultivars and among rice fractions separated by grain-milling. Variation of nsLTP1 contents were observed among rice cultivars, and rice nsLTP1 was proved to be mainly located in the outer layer of rice grains, providing evidence for decreasing nsLTP1 content by grain-milling.
The anti-Helicobacter pylori (H. pylori) activity of a water extract of Chinese chive (Allium tuberosum) (WCC) was investigated. On disk diffusion assay, WCC effectively inhibited the growth of all 21 strains tested, including isogenic mutants, showing inhibition diameters of 12 to 29 mm, irrespective of drug susceptibility and clinical manifestation. The minimum inhibitory concentration (MIC) of WCC was 2.45 mg dry weight/mL. Killing assay with multiples of MIC confirmed that WCC had bactericidal activity and that the inhibitory effects were dose dependent. In addition, to determine whether the inhibitory activity of WCC under severe stress conditions, such as heat and acidity, is altered, the stability of WCC was evaluated. The inhibitory activity of WCC exposed to acidic conditions (pH 1.0 to 6.4) was stable, while heat-treated WCC (100°C, 10 min) showed slightly decreased inhibition activity. On combination assay with antibiotics frequently used in clinical practice, WCC was found to be an innocuous agent for antibiotic activity. These results suggest that daily intake of WCC is able to prevent H. pylori colonization in the stomach, and that it could be applied as adjuvant therapy in H. pylori eradication.
Anthocyanins are pigments in plants. Anthocyanins and their aglycons, anthocyanidins, have various biological effects. In the present study, we examined the effects of cyanidin and cyanidin-3-glucoside on intracellular reactive oxygen species (ROS) levels and on proliferative effects, using four cancer cell lines and one normal cell line, and we found that cyanidin (100 μmol/L) has significant effects when compared with cyanidin-3-glucoside. Cyanidin reduced intracellular ROS levels in MCF-7, HuH-7, HepG2, Caco-2 and HUVEC cell lines, but cyanidin-3-glucoside did not. Cyanidin inhibited the proliferation of MCF-7, HuH-7, HepG2 and Caco-2 cells, but cyanidin-3-glucoside did not. Cyanidin and cyanidin-3-glucoside had no effect on the proliferation of HUVEC. We also tested cyanidin-3-rutinoside, peonidin and peonidin-3-glucoside, but the presence of a sugar in their structure hampered the biological effects of aglycons. These results suggest that a sugar in the anthocyanin structure affects biological activity.
The effects of carbonation with heating (CH) on germination of Bacillus subtilis spores were investigated. Treatment conditions for CH and heat treatment alone were set to obtain an approximate 1 log reduction in viable count. Pre-treatment of spores with CH at 80°C and 5 MPa for 30 min significantly decreased their heat resistance to a subsequent heating process at 90°C for 30 min, as compared with pretreatment by heat alone at 90°C for 30 min. Treatment with CH also decreased refractility and enhanced DAPI staining when compared with heat treatment alone, thus suggesting that CH effectively initiates and stimulates germination of B. subtilis spores.
In this work the effect of two different modified atmospheres on the growth of naturally occurring microorganisms was evaluated, in kiwifruit and in fruit based salads composed by Granny Smith apples, kiwifruits, peaches and strawberries. The stability time of the samples was modelled in order to check the effect of atmosphere packaging and to assess the most relevant microbial indices for the product quality. The obtained results showed that the stability time of the different products was strongly affected by atmosphere; in fact, packaging in both modified atmospheres, seemed to be able to prolong the stability time relatively to mesophilic and psychrotrophic bacteria and yeasts. Nevertheless, the efficacy in prolonging the stability time of the modified atmospheres was lower in fruit based salads than in kiwifruit samples. The packaging in modified atmospheres during storage resulted in a homogenous bacterial population being constituted mainly by gram-negative bacteria, whereas Rhodotorula glutinis, Cryptococcus laurentii and Candida spp. were the most commonly occurring yeasts in kiwifruit samples and Kloeckera spp. was the only yeast species isolated from fruit based salads.
We investigated the inhibitory effects of oral administration of Tetragenococcus halophilus MN45 (MN45) isolated from miso on the development of atopic dermatitis (AD) using NC/Nga AD model mice. NC/Nga mice were fed a diet containing 0.05% or 0.5% MN45 (0.05% or 0.5% MN45 groups) or lacking MN45 (control group). Mice were sensitized and boosted with picryl chloride by topical application once per week. IgE production in serum, clinical score and ear thickness in both MN45 groups were significantly suppressed. In addition, IgE and IL-17 production from splenocytes from mice in both MN45 groups were significantly decreased. IL-4 production from splenocytes in the 0.5% MN45 group decreased significantly, while IL-10 production from splenocytes in the 0.05% MN45 group increased significantly. These results demonstrate that intake of MN45 is effective in preventing and alleviating the development of type-1 allergic symptoms in humans.
In the present study, it was aimed to enrich standard cookie recipe by addition of pumpkin (Cucurbita moschat Duch. ex. Poir.) pomace powder (PPP) and carrot (Daucus carota L.) pomace powder (CPP). Two different soft wheat flour (Gerek-79 and Guadalupe) were substituted by 4 levels of PPP and CPP (10%, 15%, 20% and 25%) and the effects of increased levels of PPP and CPP on the farinogram properties of wheat flour dough and chemical composition, physical, textural and organoleptic properties of cookies were investigated. Addition of PPP and CPP increased water absorption (approximately 1.5 times), stability and development time as measured by farinograph. Cookies supplemented with PPP and CPP became darker with increasing levels of fiber and the creamy-yellow color of the control samples turned into orange-yellow. Addition of PPP and CPP decreased the spread ratio but increased breaking strength of cookies. Enriched cookies exhibited 1.5-2 times strength than control. In consideration of the results of sensory evaluation, it can be concluded that overall acceptability values decreased depending on increasing levels of PPP and CPP. Highly acceptable cookies could be obtained by incorporating PPP and CPP in both flour samples.
Combined sequential treatment using 100 mg/L sucrose monopalmitate solution under microbubble generation and soaking in slightly acidic hypochlorous water containing 30 mg/L available chlorine for 5 min at 50°C was tested for decontamination of ginger, Japanese ginger, perilla, parsley, Welsh onion and cucumber, and at 20°C for strawberry. Viable bacterial count was reduced by about 2 log cfu/g in perilla, parsley, and Welsh onion. Ginger, parsley and Welsh onion maintained viable counts of less than 5 log cfu/g during 6 days of subsequent cold storage at 6°C. Viable count for cucumber decreased by only 1 log cfu/g after combined treatment, and increased to 5.5 log cfu/g after storage for 6 days at 6°C. For decontamination of strawberry, as 50°C treatment with SAHW damaged the surface, the treatment was performed at 20°C. After combined sequential treatment, viable bacterial count decreased from 4.5 to 2.0 log cfu/g, and increased slightly to 2.5 log cfu/g after storage at 6°C for 6 days. Fungal count for strawberry also decreased from 4.9 to 2.3 log cfu/g immediately after treatment and did not increase after storage for 6 days. These results indicate the great potential of this approach in sanitization of fresh fruits and vegetables.
Freeze-thaw infusion (FI) is a new technology involving the rapid impregnation of food materials with enzymes under reduced pressure. An FI method employing protease was used to produce an angiotensin I-converting enzyme (ACE)-inhibitory peptide within soybean. Protease N “AMANO” G, the enzyme used for this method was selected after testing 11 commercial enzymes. The ACE-inhibitory peptide isolated from FI-treated soybean was identified by a three-step process involving HPLC and LC/MS/MS. Ile-Tyr was isolated as the dominant component of this ACE-inhibitory peptide, and was present at a concentration of 0.11 mg/g in FI-treated soybean.
Several angiotensin-converting enzyme (ACE) inhibitory peptides have been detected in milk products. There are many traditional milk products in Mongolia. For this study, some Mongolian milk products were collected, and the ACE inhibitory activities of these samples were tested; an active fraction was found in aaruul made from mare’s milk. After purification by dialysis and HPLC, the active fractions were isolated. The molecular weight of the active component was 362.05 M, as determined by mass spectrometry. An authentic standard was used to determine the IC50 value of the inhibitory activity. From the results of molecular weight, the active component in aaruul was identified as 5′-GMP. The activity of 5′-GMP is not much higher than that of the active peptide in sour milk and some flavonoids. However, this is the first report that shows that 5′-GMP inhibits ACE activity. These results will provide useful information for the development of hypertension therapy agents.
An improved method to determine gamma-glutamylcysteine (γ-GC) content in foodstuffs was developed using 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole as a fluorescent reagent in high performance liquid chromatography analysis. The separation of γ-GC derivatives from L-gamma-glutamyl-L-cysteinylglycine (GSH) derivatives was drastically improved when acetic acid was added to the mobile phase instead of trifluoroacetic acid (TFA), resulting in an Rs value of 5.5 compared to an Rs value of 1.4 for TFA. In addition, the linearity, recovery, and precision of analysis were proven with the use of acetic acid in this method. Using this improved method, the γ-GC content in foodstuffs such as foie gras, chicken gizzard, wet yeast, and dry yeast could be determined. The γ-GC content in these foodstuffs was approximately 1–2 mg/100 g. This improved method appears useful for determining the γ-GC and GSH contents in foodstuffs.
A polygalacturonase gene designated as AspecA was isolated from a shoyu koji mold, Aspergillus sojae KBN1340, and characterized. The structural gene comprised 1,226 bp with two introns. The open reading frame encoded a 363-residue protein with a signal peptide of 28 residues. AspecA shared a high degree of sequence identity with Aspergillus parasiticus pecA, Aspergillus oryzae pgaA and Aspergillus flavus pecA. Utilizing the promoter of the A. oryzae taaG2 gene and its signal peptide, AsPecA was successfully expressed in A. oryzae and secreted into the culture medium. AsPecA had a molecular mass of 36.0 kDa, a pH optimum of 5.0, and a temperature optimum of 50°C.
Rats were fed a high fat diet containing 0.2% black tea polyphenols, theaflavins, theasinensin A or thearubigins for 4 weeks. The hepatic cholesterol concentration was significantly lower in rats fed the theaflavins, theasinensin A or thearubigins diet than in those fed the control diet without black tea polyphenols. Theasinensin A and thearubigins significantly accelerated fecal neutral and acidic steroid excretion, respectively. These results suggest that theasinensin A and thearubigins might induce the hepatic cholesterol-lowering activity through the promotion of fecal steroid excretion.
A substantial amount of vitamin B12 (357 ± 42.7 μg/100 g) was detected in pacific bluefin tuna (Thunnus orientalis) liver using a microbiological assay method. To evaluate whether tuna liver contains true vitamin B12 or an inactive corrinoid compound, a corrinoid compound was purified and characterized. The purified compound was identical to that of authentic vitamin B12, judging by TLC and LC/ESI-MS/MS chromatograms, and 1H NMR spectral data. These results indicate that pacific bluefin tuna liver contains substantial amounts of true vitamin B12 and would be an excellent source of the vitamin.
A rapid high-performance liquid chromatographic (HPLC) method with simple extraction procedure for the determination of tocopherols in seafood was developed. A continuous isocratic elution system was used for the analysis with a mixture of acetonitrile and methanol. Tocopherols were identified by comparison of retention times and peak area values with standard of α-, β-, γ- and δ-tocopherols. The HPLC technique used showed good performance parameters (linearity r2 = 0.9999, and relative standard deviation (RSD) ≤ 12.38%). The total recoveries for each tocopherol were 99.7, 99.9, 99.8 and 99.7% for α, β, γ- and δ, respectively. This method was then applied to freshwater and seawater fish species to detect their tocopherol contents. Significant differences (P < 0.05) were observed in the content of tocopherol among fish species. The highest content was obtained from shrimp (81.3 mg/kg), while the lowest was found for whiting (9.8 mg/kg).