An issue often imposed on engineering is said to be essentially an inverse problem. Not to calculate the lethality of microorganisms in a packaged food under a given heat sterilization condition, but to find a heating condition to realize a demanded lethality is an example of inverse analysis. Using this technique, a problem that cannot be challenged through a traditional deterministic process can be solved. This article surveys the research related to the way of on-line control to appropriately manage the required heat sterilization effect on a product without knowing its thermal properties and to the manner of controlling a freezing system of a food that has thermal properties intensely dependent on temperature.
A method of determining soy sauce chromaticity by a spectro colorimetric method was investigated to objectively evaluate the chromaticity usually decided by a visual sensory test. The objective chromaticity calculated by the product of 0.6 and Commission International de l'Eclairage (CIE) 1976 lightness (L*) were lower than the ones by the sensory test. The equation 0.855L*−0.001(b*)2+0.413 (correlative coefficient 0.998) was created by multiple regression analysis, in which a dependent variable was the chromaticity decided by the sensory test and independent variables were the CIE 1976 L*, a*, b* values, to correctly calculate the chromaticity. According to the results by calibration of chromaticity values, it was confirmed that the synthesized combination of the spectro colorimetric method and the regression analysis could be applied to quality control based on the chromaticity of soy sauce in factories by installation of a proposed equation to a spectrophotometer.
The qualities of flours milled from various kinds of wheats (Norin 61, Hokushin, Nebarigoshi and Haruibuki) grown in Japan were studied for application to breadmaking. Protein contents of these wheat flours were in the range of 7.2 ∼ 10.0%, lower than that of a commercial hard-type wheat flour, Cameria (12.4%). Norin 61, Hokushin and Nebarigoshi had higher peak viscosity and breakdown, lower final viscosi-ties and setback than those of Cameria, while Haruibuki with high amylose content (29.2%) had lower peak and final viscosities than did the others. The dough made from the domestic wheat flours had significantly lower water absorption, development and stability time than that from Cameria. Among the domestic wheat flours, Hokushin had a strong consistency of dough for stretching than the others. In contrast, Haruibuki made less extensible and firmer dough than the others. Loaf volume of bread baked from the domestic wheat flours was considerably lower than that from Cameria. Also, the firmness of bread from the domestic wheat flours was significantly higher than that of Cameria after baking and during storage for 5 days. Among the domestic wheat flours, Hokushin exhibited good dough strength and big loaf volume of bread. In contrast, the present flour of Haruibuki was found to have inferior dough and breadmaking qualities.
The Food Kansei Model has been developed to formulate the causal relationships between the analyzed characteristics and perceived quality of food products. It was applied to correlate the physicochemical properties with the food perception, preference and pleasantness quantitatively. The model was applied to the practical design of flavor- and taste-active components in green tea beverages. Instrumental analyses using gas chromatography and high performance liquid chromatography were carried out for test samples of green tea beverages. Sensory evaluation was also performed by three consumer groups belonging to different social categories. The perception of tastes and flavors was summarized in new sets of uncorrelated sensory factors by applying principal component analysis to sensory data. Preferences were indicated by regression coefficients estimated to correlate hedonic ratings with the sensory factors. The relationships among the green tea components and the sensory factors were analyzed by the use of an artificial neural network. The preferable intensities of sensory factors and the concentration ratio of the components were estimated for each consumer group. Relatively high levels of roasted and sweet flavor components were found to cause higher smoothness that was preferred by female students. In contrast, female and male office workers preferred the samples containing a greater amount of flowery flavor and total amino acid, which offered greater thickness and fragrance.
Ice crystal structure was analyzed for frozen agar gel under unidirectional freezing in various operating conditions to elucidate the mechanism of the process of ice crystal growth. A linear relationship was obtained between the mean ice crystal size and the inverse of the moving speed of the freezing front. The slope of the correlation was in the same order as the diffusion coefficient of water, suggesting the important role of the molecular diffusion in this growth process. No meaningful effect of the agar concentration was observed on the ice structure showing that the agar matrix structure does not affect the ice structure in an agar concentration ranging from 1.5 to 5%.
The contribution of phytate to the gelation properties of soymilk was studied by a phytase treatment to reduce the phytate in soymilk. The breaking stress of the gel prepared from the phytase-treated soymilk was higher than that from the untreated soymilk when glucono-δ-lactone (GDL) was used as a coagulant. As the phytate content of the soy protein isolate was decreased, so the breaking stress of the GDL-gel was increased as in the case of soymilk. This result indicates that the phytate in soy protein affects its coagulative reaction and hardness of the GDL-gel. An increase in viscosity and change in the zeta potential of soymilk resulted from the decomposition of phytate.
Changes in electrical and rheological properties in freezing-thawing were measured and compared for various food materials, which could be classified into three groups. In the first group, plant tissue (vegetables and fruits) showed large and frequency-dependent impedance and clear characteristic Cole-Cole arc in their fresh state. These electrical properties drastically changed after freezing-thawing: impedance greatly decreased and the Cole-Cole arc disappeared, suggesting the serious change in the cell structure. Correspondingly, the dynamic elasticity and viscosity substantially decreased. In the second group, animal and fish meats showed the lower impedance and unclear Cole-Cole arc as compared with plant tissue, but these properties scarcely changed after freezing-thawing. Rheological properties were also unchanged reflecting the large freezing-tolerance for food materials in this group. In the third group, konnyaku (alimentary yam paste) and tofu (soyprotein curd) showed increase both in impedance and viscoelasticity after freezing-thawing reflecting the freeze-denaturation of the major components.
Characterization of the mechanisms of improvement of Chinese noodles by dry-heated egg white, were estimated by rheological and spectroscopic data of the effects of dry-heated egg white on wheat starch gel and gluten dough. The dry-heated egg white significantly increased breaking stress and elasticity of the starch gel but had little effect on retrogradation of the gel and distribution of proteins in the gel. On the other hand, the dry-heated egg white had a negligible effect on creep curves and IR spectra of gluten dough. From these data, improvement of Chinese noodles by the dry-heated egg white is believed to be due to interaction between the dry-heated egg white proteins and gelatinized starch molecules rather than gluten proteins. However, the effect of the dry-heated egg white on starch gel was unexpectedly small compared to the effect on the noodles.
In this study, the superoxide dismutase (SOD)-like activity and the ROS (superoxide anion, hydroxyl radical, singlet oxygen, t-butylperoxyl radical) scavenging activities were evaluated for the extracts from 2 varieties (black and red rices) of ancient rice brans (8 types) by the nitro-blue tetrazolium (NBT) and ESR-spin trapping methods. All the extracts from ancient rice brans (black and red rice) had SOD-like activity, which was stronger than those from present-day rice brans (Koshihikari, Akitakomachi, Haenuki). It was proven by NBT method that the activities of ancient rice brans were significantly stronger than those of L-ascorbic acid, however, L-ascorbic acid exhibited higher scavenging activity as evaluated by ESR spin-trap method. The ancient rice brans have remarkably strong ROS scavenging activities compared with those of the present-day rice brans (Koshihikari, etc.). The ROS scavenging activities and SOD-like activities of the extracts varied depending on the rice species and the planting region. In addition, the extracts from ancient rice brans inhibited the Maillard reaction, which is known to be involved in physiological aging processes. Thus, the present results suggest the utility of the extracts from ancient rice brans as antioxidative materials.
After sautéing or frying onions as a first procedure in making onion soup, major onion antioxidants (quercetin 4′-glucoside and quercetin 3,4′-diglucoside) remained mostly intact. In the onion soup prepared with sautéed onions, the quantity of flavonoids remained high, but in the onion soup prepared with fried onions, a part of them was changed during cooking. The heating stability of these flavonoids was investigated through simple boiling and oven heating of these compounds. Major onion antioxidants were quite stable in a simple cooking model of boiling and oven heating at 100°C but considerably degraded in that of oven heating at 200°C. DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity of sautéed onions was similar to that of raw onions, and fried onions exhibited much higher activity based on equivalent amounts of raw onion. Fried onions had much higher browning degree than sautéed onions, and the browning substance was found to contribute to the radical scavenging activity. The onion soup prepared with sautéed onions had DPPH radical scavenging activity similar to plain sautéed onions, but the onion soup prepared with fried onions had much lower activity than fried onions alone.
Effects of gamma-irradiation at doses of 1, 5, 10 kGy on electrophoretic patterns of insoluble proteins, water absorption properties and cooking quality of dry bean and chickpea samples were investigated. SDS-PAGE patterns of the samples in each variety did not differ in terms of relative mobilities. The densitometric analysis results indicated that the effects of irradiation on SDS-PAGE patterns of dry bean and chickpea proteins seem to be minor. Generally, lower irradiation doses did not significantly affect the water absorption properties of the food legumes. On the other hand, the dry and wet cooking times of the irradiated samples were found to be significantly reduced in all dry bean and chickpea samples.
Effect of direct current on soymilk coagulation was studied to establish a new processing method for food. Soymilk was treated with direct electric current (60 mA) in an anode chamber. The treated soymilk gave tofu-like gel only by simple heating. The obtained tofu-like gel showed appearance and texture similar to a commercial kinu-tofu. Sodium dodecyl sulfate gel electrophoresis showed that the electric treatment did not change the state of covalent cross linkage including disulfide bridges among the soybean protein molecules. Therefore, non-covalent intermolecular interactions may play an important role in the gel network formation. Though the oxidation of the soymilk in the anode chamber cannot be ruled out, the treated soymilk caused almost no change on peroxide value of the oil component, the active chloride content or the oxidation-reduction potential. Nor was any mutagenicity observed for the treated soymilk. Therefore, the electric treatment with direct current is considered a safe technique for food processing.
Gastrointestinal disorders after ingesting a sports drink were investigated during bicycle exercise. The experiment consisted of a preliminary exercise, a 10 min rest, and 30 min of exercise. Seven healthy untrained volunteers ingested either water or a sports drink based on highly branched cyclic dextrin (HBCD), commercially available dextrin of DE16 or glucose immediately after the preliminary exercise. The mean gastric emptying time after ingestion of the HBCD-based sports drink was significantly faster than that of the glucose-based drink. Gastrointestinal disorders were monitored by a questionnaire. The mean degree of subjective flatulence and the mean number of belches were few with the HBCD-based drink during exercise. When volunteers drank the sports drink based on 10% HBCD during bicycle exercise, they experienced few gastrointestinal disorders and consequently could continue the exercise comfortably with little fatigue.
In the current studies, we produced a purple sweet potato lactic acid bacteria drink (PSPLABD) using a variety of lactic acid bacterial strains. The various PSPLABD were analyzed for color, pH, and flavor. We found that Lactobacillus helveticus B-1 was the most efficient strain for fermentation. In addition, optimal conditions included a purple sweet potato content of 10%, a skim milk content of 7%, a white sugar content of 7.5%, fermentation at 35°C, and a pH adjusted to 3.5 (fermentation time ∼24 h). PSPLABD had 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity (IC50 = 130 μl) and inhibited lipid peroxidation (equivalent to 103 μM butylated hydroxytoluene). Fermentation had no effect on the antioxidant activity of PSPLABD, but the purple sweet potato and the lactic acid bacteria drink components had a synergistic effect on the inhibition of lipid peroxidation. Thus, the PSPLABD could be used as a health food which has antioxidant activity and an appealing flavor and color.
Application of a colorimetric method for determination of lipid peroxides in foods was investigated. We identified the optimal amount of potassium iodide used in the method. It was confirmed that by adopting this optimal amount the method could be satisfactorily applied to triacylglycerols and free fatty acids. Furthermore, in order to extend the scope of its application to phospholipids, we made several additional modifications including replacement of the solvent and established an improved technique applicable to phospholipids having a peroxide value of 40 or more.
In this research, selected bakery products that contain high amount of fat (>10%) were stored under ambient conditions until the end of shelf life. Changes in oxidative stability and fatty acid composition of the samples including biscuits, crackers, wafer and fruit cake were determined with three months of interval. Free fatty acidity, peroxide value, and Rancimat induction times changed significantly (p < 0.05) in all samples. However, acidity and peroxide values remained under the maximum limits allowed by standarts. Total fat contents ranged from 13.3% (petit beurre) to 27.1% (wafer), and the major fatty acids in the samples were palmitic, stearic, oleic, trans oleic, and linoleic acids. Changes in unsaturated fatty acids which majorly affects the lipid oxidation were insignificant (p > 0.05), and according to the obtained results all samples maintained their oxidative stability throughout shelf life.
Chinese cabbage (Brassica campestris L. ssp. Peckinensis) is the most widely consumed Brassica vegetable in Asian countries including Korea. Brassica vegetables contain glucosinolates, which have been known to contribute health promotion of human being. Glucosinolates are hydrolyzed into isothiocyanates and other breakdown products. Glucosinolates in the Chinese cabbages were characterized using not only GC and GC/MS but also HPLC and LC/MS. The major glucosinolates in Chinese cabbage were identified as 3-butenyl, 4-pentenyl, and 2-phenylethyl glucosinolates, which were gluconapin, glucobrassicanapin, and gluconasturtiin, respectively.
Allium such as leek (A. ampeloprasum L.) and scallion (A. chinense L.) powders blended with wheat flour improved the breadmaking properties of bread height (mm) and specific volume (cm3/g). Brabender farino-graphs of the Allium (leek and scallion) powder/wheat flour showed remarkable changes in the profile such as width of the tail. Size-exclusion high performance liquid chromatography (SE-HPLC) of the wheat proteins in the Allium (leek and scallion) blended or not blended wheat flour showed a profile of low, medium and high molecular weight peaks. The area of the high molecular weight peak of the wheat proteins was larger in the Allium blended flours than in control (wheat flour) indicating that these protein fractions were related to the improvement in breadmaking properties.
A bioactive factor inhibiting adipocyte differentiation was found in the water-soluble fraction of Maitake (Grifola frondosa). The fraction including bioactive factors was isolated by HPLC on Superdex Peptide HR 10/30. This water-soluble fraction was found to inhibit the differentiation of adipocytes as determined by the decrease in the glycerol-3-phosphate dehydrogenase (GPDH) activity, triglyceride (TG) accumulation and leptin levels. Furthermore, this factor inhibited the expression of peroxisome proliferator activated receptor γ(PPARγ), one of the master regulators expressed early in adipocyte differentiation cascades. Thus, this bioactive factor may act on the expression of some factors at earlier stages leading to the expression of PPARγ.
To investigate the long-term effect of feeding royal jelly (RJ) on the testicular function, 32-week old male golden hamsters were fed diet containing RJ at doses of 0 μg/g diet (control), 50 μg/g diet or 500 μg/g diet for 12 weeks. At the end of the experiment, the hamsters were assessed for testicular function in terms of the amounts of intra-testicular free testosterone (TS) and histopathological changes. RJ diet groups showed higher TS levels and more intensive spermatogenesis than the control group in a dose-dependent manner. The intensity of spermatogenesis and TS levels in the 500 μg of RJ/g diet group showed significant differences of p < 0.01 and p < 0.05, respectively, when compared with those in the control group. These results indicate that the long-term feeding of RJ inhibits the age-associated decline in the testicular function of male hamsters.
A spectrophotometric assay system for evaluating reducibility of water-soluble substances using native bovine oxymyoglobin (MbO2) was developed. With incubation of MbO2 solution at fixed temperature and pH, the autoxidation rate to metmyoglobin (metMb) was measured. The reductive effects of test samples on metMb could be estimated as numerical values based on the changes in the rate constants from MbO2 to metMb. The reductive effects of four kinds of water-soluble compounds were examined: L-ascorbic acid (AsA) strongly reduced the autoxidation rate of MbO2, glutathione and kojic acid showed reductive effects inferior to that of AsA, while gallic acid tended to promote autoxidation at high concentrations. The results of test compounds obtained by the present MbO2 assay were compared with data by ferricyanide assay and XTT assay, which are known methods for evaluating reducibility. The MbO2 assay is useful because of its superior features of sensitivity, application flexibility and capability of evaluating pro-oxidant activity of reducing agents.
The production of the high quality rice called brand rice is the increaseing year by year with about one hundred thirty five kinds is known by the name of the place it is produced. We analyzed using GC and GC-MS the volatile components of ten kinds of rice harvested from 2000 to 2002 years. The results indicated that six kinds of carbonyl compounds; Propanal, 1-Butanal, Methyl Ethyl Ketone, 1-Pentanal, 1-Hexanal, and 1-Heptanal, were one causes of the old rice smell. Moreover, Methyl Ethyl Ketone and 1-Pentanal and Propanal were deeply involved in this smell, while 1-Butanal and 1-Heptanal were involved in a fresh rice smell. Furthermore, as for the quality of aroma and the change in strength, it was measured objectively using an Aromalizer (TM). That result, old rice-ization proceeded to have said since before, it was found that the aroma was strongly indicated to be the result of the quality analysis of the rice by the sensor.
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