Fatty acid composition has become recognized as an important trait in beef because of its relationship with beef quality, including beef flavor and tenderness. Our laboratory attempted to identify genes responsible for the fatty acid composition of cattle. We found several such genes and developed genetic markers of fatty acid composition. The findings were as follows. 1) Genetic polymorphisms of the stearoyl-CoA desaturase (SCD) gene are associated with fatty acid composition. The effects of SCD type A gene substitution on the percentage of monounsaturated fatty acid (MUFA) and the melting point of intramuscular fat were on average approximately +1.0% and −1.0°C, respectively. 2) Intron polymorphisms of sterol regulatory element binding protein-1 (SREBP-1) also affected MUFA. 3) No effect of SCD or SREBP-1 genotypes on any representative carcass traits of Japanese Black cattle was observed in the field population. 4) Additional genetic markers, adipocytes fatty acid binding protein 4 (FABP4) and liver X receptor α, also affected the fatty acid composition. 5) SCD and FABP4 significantly affected fatty acid composition of Holstein steers. These findings bring new insights into the fat-related carcass traits of beef cattle. In addition, the developed DNA makers will contribute to improved meat quality of beef.
In this study, the feasibility of the application of nanofiltration to recover excess benzoic acid from cranberry juice was investigated. Different kinds of commercial nanofiltration membranes were screened for their ability to separate benzoic acid from cranberry juice. There were 7 kinds of membranes, including HC50, NFT50, G5, Desal-DK, DRA4510, UTC60 and NTR7250, which showed significantly lower rejection of benzoic acid than that of other components in cranberry juice, such as sugars, other organic acids (citric acid, malic acid and quinic acid) and anthocyanins, with a difference of over 40 %. The effect of pH on nanofiltration was also investigated; the separation was very effective at pH 4.5. The rejection of benzoic acid was negative (lower than −40 %) and significantly different from the rejection of other components. It is promising to recover benzoic acid from cranberry juice by nanofiltration.
GC-MS fingerprint analysis, principle component analysis (PCA), and partial least square (PLS) analysis were introduced for detection and quantification of paraffin in beeswax. Firstly, beeswax, paraffin and standard adulterated samples were prepared and analyzed by GC-MS. Secondly, seventeen chromatographic peaks were selected as characteristic peaks and their relative peak areas (RPAs) were calculated for quantitative expression of the GC-MS fingerprints. Then, the PCA is performed after a suitable data processing. The scores of PCA showed that two types of beeswax and paraffin could be clustered reasonably into different groups. Lastly, Seven PLS factors were selected to build the PLS model with cross-validation. The plot of the predicted concentration versus the actual concentration values appeared to show the high precision of model. Therefore, GC-MS fingerprint in combination with chemometric techniques provide a very flexible method for detection and quantification of paraffin in beeswax.
We found that brown rice flour produced using a jet mill after soaking for more than 12 h yielded a better formulation of rice/gluten bread, giving an equivalent specific loaf volume (SLV) as bread made with white rice flour. Quality analysis of the brown rice flour showed that soaking for more than 12 h resulted in a lower damaged starch content. There was a significant inverse correlation between damaged starch content and SLV. Substitution of 10% white rice flour with rice bran had little effect on final SLV. Furthermore, endogenous α-amylase activity in brown rice flour produced after soaking was approximately 5 to 12 times higher than that of white rice flour, but there was no correlation with SLV. These results indicate that the improved SLV in brown rice/gluten bread was predominantly due to the decrease in damaged starch content, which depends on soaking time.
The effect of aluminium cookware on inactivation of Escherichia coli in milk was studied. Samples in aluminium and stainless-steel cups were heated at 60, 63, 65 and 67°C and held at those temperatures for 25, 5, 3 and 2 min, respectively. Results obtained under the temperature of 65 and 67°C clearly showed that cells of E. coli were killed more rapidly in aluminium cups than in stainless-steel cups. D-values in the aluminium cups were significantly shorter than those in stainless-steel cups, especially at higher temperatures. Samples in aluminium cups revealed a better trend inactivation effect than in stainless-steel cups at 60 and 63°C, however, there were no significant difference. Considering on z-values, results which obtained by aluminium cups were slightly lower than that obtained by stainless-steel cups. These results indicate that an aluminium utensil has an inactivating effect on E. coli and that rate of inactivation increases as temperature increases.
Defatted rice bran was treated with water or aqueous ethanol under subcritical conditions to recover materials with antioxidative activity. The extraction conditions, namely ethanol concentration (10−100% (v/v)), temperature (120−237°C) and time after attainment of a desired temperature (5−60 min), were studied. On the basis of the determinations of total carbohydrate, protein and phenolic contents, yield, DPPH radical scavenging activity, and antioxidative activity against oxidation of bulk linoleic acid, the extraction with 20% (v/v) ethanol at 237°C for 5 min was concluded to be comparatively more efficient than that by subcritical water at the same extraction temperature for the same length of time.
In this study, primer sets of L. monocytogenes virulence gene hlyA were designed for the L. monocytogenes-specific PCR assay. To evaluate the performance of these primer sets, the detection sensitivity and specificity were examined and the most suitable primer set was selected. Subsequently, it was subjected to compare the performance for detection of L. monocytogenes with commercially available kits (TaKaRa detection kit and ABI detection kit) on DNA level. Results of real-time PCR showed that the efficiency of this new primer set was 101.6% while TaKaRa and ABI detection kit were 101.1% and 107.4%, respectively. The detection sensitivity of all three methods was equivalent to less than 1 copy per reaction using purified genomic DNA as template. Detection specificity were 100% when testing L. monocytogenes isolates, and for other Listeria isolates were 15.4%, 76.9% and 100% by the method using hlyA L. monocytogenes detection primer set 7, TaKaRa and ABI detection kit, respectively. In summary, this new PCR detection method is relatively sensitive and more specific to L. monocytogenes under certain conditions, could serve as a rapid detection method and has the potential for detection of L. monocytogenes from contaminated food.
An acid phosphatase gene (aphA gene) from an industrial miso koji mold strain, A. oryzae KBN630, was disrupted by using the recently developed homologous gene replacement system for this strain. The aphA gene disruption did not affect growth on steamed soybean. Acid phosphatase production decreased by approximately 20% in the aphA gene disruptants compared with that of the wild-type strain. Utilizing the promoter of the A. oryzae TEF1 gene, AphA expressed in A. oryzae was successfully secreted into the culture medium. AphA had a molecular mass of 58.0 to 65.0 kDa, a pH optimum of 4.0, and a temperature optimum of 40°C. AphA had the ability to release inorganic phosphate from GMP and IMP. This is the first report to show directly that an A. oryzae acid phosphatase has the ability to hydrolyze GMP and IMP.
During food processing and cooking, various flavor compounds, colored substances and toxic substances are produced by the Maillard reaction. It is important to investigate the relationship between the Maillard reaction products and the actual cooking conditions. Therefore, we investigated the effects of seasonings and reaction conditions on the Maillard reaction of meat using furosine and fluorescent compounds. The addition of 1.0% NaCl decreased the reaction rate of the Maillard reaction measured by furosine in Glc - meat reaction. However, the reaction rate of meat with added sucrose did not change. Furosine content in meat with added sucrose increased rapidly when it was pan-broiled and fried, but increased slowly at the beginning when it was baked in a gas oven. The fluorescence of broiled meat showed a maximum at 333/425 nm (exc./em.) and is a useful indicator of the Maillard reaction of meat samples. The rate of increasing fluorescence in baked meat was lower than that of meat heated by other cooking methods.
The lactic acid bacterial flora in commercial and homemade Funazushi (fermented crucian carp and rice) were investigated. Funazushi is a fermented fish product that continues to be produced in the traditional style in Japan. Lactic acid bacteria in four commercial and five homemade Funazushi were enumerated. The viable counts of commercial samples ranged from 3.0 × 103 to 2.7 × 105 cfu/g, with an average of 2.4 × 104 cfu/g, while the viable counts of homemade samples ranged from 2.0 × 102 to 2.6 × 107 cfu/g, with an average of 1.3 × 105 cfu/g. Twenty-seven lactic acid bacteria isolates were obtained from the commercial samples, and identified as Streptococcus salivarius, Lactobacillus buchneri, and Lactobacillus parabuchneri. Forty-eight isolates were obtained from the homemade samples, and identified as Lactobacillus plantarum, Lb. buchneri, Lactobacillus alimentarius, Lactobacillus farciminis, Lactobacillus acidipiscis, and Lactobacillus casei. Lb. buchneri was the predominant species in commercial Funazushi, while Lb. plantarum and Lb. buchneri were the predominant species in the homemade products.
Aspergillus oryzae KBN8048 was selected as a strain exhibiting low level acid phosphatase activity in solid-state rice and soybean cultures for miso brewing. The activity was particularly low in the latter case, and was correlated with decreased dephosphorylation activity of IMP, an enhancer of miso palatability. Based on transcriptional properties, 13 acid phosphatase genes in the fungus were classified into type R and type S, which exhibited higher expression in solid-state rice and soybean cultures, respectively. Type R genes appeared to be up-regulated in response to acidic pH and limited phosphate availability in the culture via a pH-dependent transcriptional factor, PacC, and a functional counterpart of Saccharomyces cerevisiae Pho4p, which transcriptionally activates phosphatase genes under phosphate-limited conditions, respectively. On the other hand, existence of type S genes suggested an unknown mechanism that responds to inductive regulatory cue(s) other than pH and phosphate availability in solid-state soybean culture.
The aim of this study was to evaluate the probiotic potential of 35 strains of Lactobacillus spp. isolated from dahi a traditional fermented milk product. In order to select the candidate probiotic strains Lactobacillus spp. isolated belonged to the L. delbrueckii subsp. bulgaricus, L. acidophilus, L. casei and L. helveticus were examined for antimicrobial activity against selected pathogens, acid and bile tolerance and antibiotic susceptibility. It was observed that L. acidophilus LA 02 produced antimicrobial activities against the test strains and tolerated pH 2 and 3 and survived the bile salt concentration of 0.1, 0.2 and 0.3 %. It was resistant to vancomycin, erythromycin and chloramphenicol. This is the first report describing the probiotic properties of dairy isolates of Lactobacillus spp. in Pakistan.
Biochemical properties (free amino acids, organic acids, and peptide molecular weight (MW) distribution) were determined in the extract of rice bran discarded after heshiko meat processing (heshiko rice bran), as well as the effect of the extract on systolic blood pressure (SBP) in spontaneously hypertensive rats (SHR). The biochemical properties of heshiko rice bran extract were highly similar to that of heshiko meat extract. The former exhibited a hypotensive effect on SBP at almost the same level as observed for the latter when administered singly and successively to SHR. Storage for 90 days at 30°C of raw rice bran, as well as mixtures of raw and heshiko rice brans at various ratios, resulted in a marked increase in peptide content. The storage of raw rice bran and heshiko rice bran had little effect on the efficacy of a single administration of their extracts on SBP. The extracts from the rice bran mixtures stored for 90 days decreased the SBP to a larger extent than the extracts from the mixtures without storage, and the larger decrease of SBP was due to the mixing and the storage. These results strongly suggest that hypotensive peptides are produced in the rice bran during heshiko meat processing, and act to decrease SBP in SHR.
A fast and simple high-performance liquid chromatographic UV-Vis method for the determination of astaxanthin in human plasma was developed and validated. The method involved direct injection of plasma sample after deproteinization using a 1:9 mixture of ethanol-tetrahydrofuran. The mobile phase comprised methanol:water:ethyl acetate (82:8:10% (v/v)) with a total run time of 5 min. Analysis was run at a flow rate of 1.5 mL/min with the detector set at 474nm. This method is specific and sensitive, with a quantification limit of approximately 0.25 µg/mL. The calibration curve was linear over a concentration range of 0.39 − 50.0 µg/mL. The method had a mean absolute recovery of 99%, while the within-day and between day coefficients of variation and percentage errors were all less than 3%. The speed, specificity, sensitivity, reproducibility and stability of this method make it suitable for the determination of human plasma astaxanthin in routine analysis.
Polyamines are important constituents of all mammalian cells. We previously found that polyamines in soy yogurt, a mixture of fermented soymilk and okara, absorbed easily in the small intestine of growing rats, but the polyamine level in plasma scarcely increased. The level of polyamine in the body tends to decrease with age. In the present study, we investigated changes in polyamine levels in the intestines and plasma of adult rats to clarify the effect of soy yogurt in supplying polyamine to the plasma in adult rats. The polyamine levels in the intestine and plasma of adult rats increased significantly after ingestion of soy yogurt. It was found that soy yogurt is useful for the recovery of polyamine in adult rats.
Male mice (4 months old) were fed a 5% lard or fish oil diet supplemented with 0, 1, or 2 ppm methylmercury (MeHg) chloride for 4 months to investigate the interactive influence of dietary fat and low level MeHg exposure on antioxidative factors and mercury accumulation in the tissues of mice. Exposure to low levels of MeHg significantly decreased plasma ascorbic acid concentration, but not the influence of brain potential antioxidant (PAO) activity, regardless of dietary fat. Total mercury concentrations were significantly lower in the muscle and higher in the plasma of the fish oil diet group compared with those of the lard diet group. Brain mercury content was hardly influenced by dietary fat. These results indicate that dietary fat may influence the accumulation of mercury in muscle but it scarcely influences oxidative factors induced by low level MeHg exposure.
We investigated the effects of citric acid and lemon juice on iron absorption and improvement of anemia in iron-deficient rats. In Expt. 1, rats were administered ferric iron solution (2 mg/kg) with various concentrations of citric acid (1 − 6%) by a single oral gavage. The serum iron levels were significantly higher in rats treated with citric acid than those without citric acid. In Expt. 2, anemic rats were administered ferric iron solution (control) with 1% citric acid or diluted lemon juice containing 1% citric acid by oral gavage dose of 2 mg Fe3+/kg/day for 20 d. Heart weight and unsaturated iron-binding capacity (UIBC) were significantly lower in the citric acid group, whereas serum iron level and hematocrit value were significantly higher in the citric acid group than in the control group. Hemoglobin concentration was significantly higher in the citric acid group and lemon juice group. These results suggest beneficial effects of citric acid and lemon juice on iron bioavailability.