Microbial control of postharvest diseases has been extensively studied and appears to be a viable technology. Food safety must be ensured at each postharvest processing step, including handling, washing of raw materials, cleaning of utensils and pipelines, and packaging. Several commercial products are available for this purpose. The time is ripe for developing new techniques and technologies. The use of electrolyzed water (EW) is the product of a new concept developed in Japan, which is now gaining popularity in other countries. Little is known about the principle behind its sterilizing effect, but it has been shown to have significant bactericidal and virucidal and moderate fungicidal properties. Some studies have been carried out in Japan, China, and the USA on the pre- and postharvest application of EW in the field of food processing. EW may be produced using common salt and an apparatus connected to a power source. As the size of the machine is quite small, the water can be manufactured on-site. Studies have been carried out on the use of EW as a sanitizer for fruits, utensils, and cutting boards. It can also be used as a fungicide during postharvest processing of fruits and vegetables, and as a sanitizer for washing the carcasses of meat and poultry. It is cost-effective and environment-friendly. The use of EW is an emerging technology with considerable potential.
Quality of frozen tiger puffer meat was evaluated in a comparative study with frozen yellowtail. After being frozen by air blast freezing, the fish samples were stored at -50°C for 1-6 months. Two different methods of thawing were tested ; in running water at 17°C and in still air at 4°C. The breaking force of fish meat for yellowtail decreased rapidly over the first month, however, no significant difference was observed for the tiger puffer regardless of freezing duration. The amount of free drip in the yellowtail was relatively low compared that observed in the tiger puffer which increased continually for three months. Histological observations showed less damage in the tiger puffer cells than in the yellowtail, with cell structure prior to thawing in the yellowtail being subjected to significant extracellular freezing, while intracellular freezing occurs in the tiger puffer.
The effects of adding gelatinized starches to a kneading dough (a process known as yukone in Japanese) on the crumb grain of baked white breads were studied using magnetic resonance imaging (MRI) and using scanning electron microscopy (SEM) with and without distilled-water soaking of the samples. MRI revealed that pores became larger and rounder in yukone breads compared to control breads using the sponge dough method, while the number of pores decreased in yukone breads. SEM revealed many starch granules on the surface of pore walls in the control breads, whereas the yukone breads contained starch gels cemented between starch granules. Gluten nets were found to be uniform and oriented in the control breads and became thicker and coarser in the yukone breads. Comparing the SEM images of two commercial white breads made by the yukone method, the fine gluten nets under the starch walls were found to be considerably different.
Frozen surimi (fish-meat) gel samples with different moisture contents were subjected to measurement of their fracture stress (bending energy) in a low temperature range. The optimum conditions for low-temperature cutting ( ”cryo-cutting”) were estimated from the values of enthalpy change measured by a differential scanning calorimeter (DSC). Frozen surimi gel of 90% moisture could not be cut by bending at -40°C, although it could be cut this way at -60°C. The temperature, A, at which surimi gel starts to be cut by bending fell in conjunction with a reduction in moisture content. Bending energy was observed to fall around -70°C and was nearly constant below temperature B. The glass transition start point temperature (Tig) obtained by DSC measurement corresponded to temperature B and the glass transition end point temperature (Teg) corresponded to temperature A. As a result, the appropriate cutting temperature as calculated by DSC measurement was below -80°C, but was dependent on moisture content.
We extracted the protein fraction (QP) from quinoa seeds. Mice were fed on 0.5% cholesterol diet, containing 0%, 2.5% and 5.0% of QP (control, QP 2.5% and QP 5.0%, respectively) for 4 weeks. Neither supplemental QP diet produced a difference in food intake and body weight gain. The QP supplementation significantly prevented the increase in plasma and liver total cholesterol levels. Fecal weight and excretion of bile acids in the QP groups was significantly higher than in the control group. QP showed bile acid-binding activity in vitro. Expression of mRNA of 3-hydroxy-3-methylglutaryl coenzyme A reductase in the liver, a key enzyme for cholesterol biosynthesis, was suppressed by the QP diet, whereas the expression of cholesterol-7α-hydroxylase, a cholesterol catabolic enzyme, was found to be stimulated. These results suggest that the prevention of increases in plasma and liver cholesterol levels in mice fed the QP diet can be ascribed to the inhibition of the re-absorption of bile acids in the small intestine and control of cholesterol synthesis and catabolism.
The cecal microflora of rats coadministered Lactobacillus rhamnosus KY-3 (L. rhamnosus KY-3) and cellobiose was analyzed by fluorescence in situ hybridization. When compared with L. rhamnosus KY-3 administration alone, simultaneous administration of L. rhamnosus KY-3 and cellobiose led to an increase in the number of lactic acid bacteria (LAB), particularly L. rhamnosus, and a significant decrease in the number of Gammaproteobacteria in the cecum. These results indicate that administration of L. rhamnosus KY-3 cells passed through the upper digestive tract to the cecum where it is likely that they proliferated through the assimilation of cellobiose.
We evaluated the volatile compounds of Japanese green tea using GC/O with the original aroma simultaneously input to the sniffing port (OASIS) method in order to determine the relationship between the volatile compounds and the green tea aroma. Application of OASIS to the volatile fractions of Japanese green tea infusions revealed 11 odor-active peaks. Those of cis-1,5-Octadien-3-one, 4-mercapto-4-methyl-2-pentanone, 3-methylnonane-2,4-dione, geraniol, decanal and cis-3-hexenol emphasized the green note of the tea. 2-Acetylpyrrole, 2-ethyl-3,5-dimethylpyrazine and 2-acetyl-3,5-dimethylpyrazine emphasized the roast note. Indole strengthened the overall green tea odor. β-Ionone emphasized the sweet note in the green tea. Of these odorants, 2-acetyl-3,5-dimethylpyrazine was identified for the first time as a volatile compound in tea.
A mixture of genistein, daidzein and bisphenol A was intragastrically given to male Sprague-Dawley rats. The tissue distribution of these compounds and equol, a metabolite of daidzein, was examined by high-performance liquid chromatography after administration. In the serum, liver and kidney, genistein, daidzein and bisphenol A were clearly detected at 6 to 24h. Equol was detected at 0h and levels subsequently dropped and then increased again, reaching the initial level at 24h. In the mesenteric lymph node (MLN), thymus and spleen, genistein and daidzein were detected at 6 to 24h. Bisphenol A and equol in the MLN was detectable at 6 to 24h and 24h, respectively. In the testicle, epididymis, spermatheca and prostate, higher levels of genistein and daidzein were detected around 6h. Bisphenol A was detected in the epididymis at 6 to 12h. These results suggest that the distribution of these chemicals and their tissue affinities in rats vary from tissue to tissue.
Sea cucumber is a traditional food item in Asia and has been reported to exhibit antifungal, antitumor, and antioxidant bioactivity as well as other properties. In this study, sea cucumbers were treated with hot water at 98°C for 60min to prepare extracts that were then used to assess their effect on the proliferation and H2O2 susceptibility of human colon adenocarcinoma Caco-2 cells. The growth of Caco-2 cells was significantly inhibited by sea cucumber extracts in a dose dependent manner. Cell proliferation was inhibited by high molecular weight sea cucumber extract at a concentration of 0.108mg/mL. No growth was observed at 1.04mg/mL of the hot water extract after 96h incubation. Cell damage by sea cucumber extract was evident above 1mg/mL. H2O2 showed concentration dependent cytotoxity to Caco-2 cells. In addition, coadministration of sea cucumber extracts intensified the H2O2 cytotoxity.
An α-galactosidase gene belonging to glycoside hydrolase family 27 from Streptomyces coelicolor was cloned and expressed in E. coli. The purified enzyme showed a single protein band on SDS-PAGE with a molecular mass of 64kDa. It was quite stable from pH 5.0 to 10.0 after treatment at 40°C for 60min, and was thermally stable up to 50°C. The enzyme acted on galacto-oligosaccharides, galactomanno-oligosaccharides and galactomannans as well as plant α-galactosidases. It consisted of an N-terminal catalytic domain (400 amino acid residues) and a C-terminal region (260 amino acid residues). The catalytic domain of the enzyme was constructed by deleting the C-terminal region from the enzyme and was found to be stable from pH 5.5 to 8.5 and up to 40°C. The catalytic domain showed the same specificity towards galacto-oligosaccharides, galactomanno-oligosaccharides and galactomannans as the enzyme containing the C-terminal region. These results indicated that the Cterminal region probably has an important role in stabilizing the enzyme.
Minimum inhibitory concentration (MIC) isobolograms of fresh garlic extract (FGE) and NaCl against Staphylococcus aureus test strains ATCC 25923 and ATCC 6538 in Brain Heart Infusion broth (BHIB) and Pork Sausage broth (PSB) were constructed. Additive and synergistic relationships were observed in BHIB and PSB against the test strains, respectively. Action of indirect antimicrobic ingredients in PSB was used to explain the synergistic relationship of FGE and NaCl established. The Fractional Inhibitory Concentration (FIC) indices of the agents validated the antimicrobic relationships established in the MIC isobolograms. An Iodonitrotetrazolium-Direct Microscopic Count (INT-DMC) method was used to measure staphylococcal cell count reductions in both broth systems containing concentrations of FGE and NaCl typically used in sausage production. Garlic incorporation of ≥1.20 (v/v) together with minimum levels of NaCl (<2% w/v) can be recommended in cured pork sausage formulations for control of staphylococcal growth.
Several novel antioxidative peptides from the hydrolysate of water-soluble royal jelly protein (WSRJP) were isolated, identified, and characterized. WSRJP was extracted from royal jelly and hydrolyzed with protease N, and the resulting hydrolysate was fractionated by ultrafiltration with cutoff membranes of 1 and 3kDa. Three fractions (<1kDa, 1-3kDa, and>3kDa) were separated. The antioxidative activity of the fractions against the peroxidation of linoleic acid was determined in vitro, using the 1,3-diethyl-2-thiobarbituric acid method. The<1kDa fraction, which exhibited the highest antioxidative activity, was further purified using anion-exchange and reverse phase high performance liquid chromatography. Fourteen antioxidative peptides were identified using a protein sequencer and electron spray ionization-mass spectrometry. Among these, four dipeptides (Phe-Asp, Trp-Val, Leu-Trp, and Trp-Leu) were revealed to have potent antioxidative activity against lipid peroxidation. Moreover, three of these antioxidative dipeptides (Phe-Asp, Trp-Val, and Leu-Trp) were found to protect against oxidative stress-induced cell death in human cultured cells.
This study was undertaken to estimate the effect of high-oleic peanut oil (HO) on the promotion stage of lung tumorigenesis in mice. On day 30 after methyl nitrosourea administration, dietary HO inhibited ornithine decarboxylase activity, induced the inactivation of Mek, and reduced the level of proliferating cell nuclear antigen in lungs of mice more than did high-linoleic safflower oil. A parallel effect was observed in the level of prostaglandin E2 in the lungs. These results suggest that HO suppresses the promotion stage of lung tumorigenesis in mice and that the suppression correlates to the level of PGE2.
The heat resistance characteristics of Salmonella Enteritidis (BIOTECH 1963) at 60°, 65° and 70°C in liquid quail eggs (LQE) and peptone-saline (PS) were determined using various non-selective and selective recovery plating media. The highest mean D-values recorded in LQE at 60°, 65° and 70°C were 3.11, 2.50 and 2.20min, respectively. Generally, the mean D-values in PS at all test temperatures were lower than in LQE. The highest established Z-values in LQE and PS were 21.71°C and 13.52°C, respectively. The potential of using the heat resistance parameters established in the study in the calculations for pasteurization schedules for LQE was recommended.
We examined the correlation between amount of curcumin intake and its physiological effects on indices of liver function, serum and liver lipid profiles in rats. Animals were fed diets containing 0.5, 5 and 50mg curcumin per 100g body weight for 28 days. HDL-cholesterol concentrations of rats fed curcumin diets were significantly higher (P<0.05) than those of the control group, and serum TG concentration of rats fed the x100 curcumin diets was significantly lower (P<0.05) than that of the x1 curcumin group. Serum TG concentration of rats fed curcumin diets tended to decrease in a curcumin dose-dependent manner. These results indicate that curcumin intake can improve serum lipid profiles effectively.
Debaryomyces hansenii NBRC 0855 accumulated high amounts of glucosylceramide relative to 25 strains of salt-tolerant yeasts in the genera Candida, Debaryomyces, Kodamaea, and Pichia. The constituents of glucosylceramide were principally 2-hydroxystearic acid as a fatty acid, 9-methyl-trans-4, trans-8-sphingadienine as a sphingoid base and glucose as a hexose. Strain NBRC 0855 was able to produce glucosylceramide when cultured on actual effluent from a pickle manufacturer.