Now in Japan, healthy foodstuffs have been strongly requested, and several kinds of saccharides were developed for the purpose of cholesterol reduction, stool regulation, belly conditioning, protection from caries, bifidus factor etc. Polysaccharides, reserve saccharides such as starch, structural polysaccharides such as cellulose, hemicellulose and chitin show some biofunctional effects according with their molecular weight and structure. Especially the density and the location of branches may play an important role in biofunctional effects, and the branches should be at every key point. Several kinds of oligosaccharides having 2-5 units and polysaccharides were commercialized as healthy foodstuffs. Oligosaccharides having biofunctional effects against plants and microbes were also composed of around 6 units of monosaccharide. Moreover, even monosaccharides themselves having a certain structure show some biofunctional effects.
The applicabilities of Epstein and Plesset's theory and Lemlich's theory to the change in bubble-size distribution under a constant temperature were studied on bubbles impregnated in homogeneous viscous solutions. The numerical calculation based on Epstein and Plesset's theory that took into account the change in the dissolved air concentration in the surrounding solution agreed well with the measured results, while Epstein and Plesset's theory, which assumed the dissolved air concentration in the surrounding solution to be constant, and Lemlich's theory, did not fit the measured results.
Most of the published methods to predict temperature history during food freezing require knowledge of the thermal properties of foods. However, it is difficult to estimate the precise thermal properties of food which show a significant change during freezing. In this paper, an inverse numerical procedure was developed using the modified Marquardt iterative method; a procedure which collects time/temperature data during the early stages of cooling, analyzes these data to determine the thermal property coefficient ratio associated with the heat conduction equation and predicts the time/temperature profile during the remainder of the freezing phase using the system parameters. A numerical experiment using the literature data of lean beef validated that this procedure was able to predict the temperature history even when the measured temperature included a random error of ±0.2°C.
Konjac mannan absorbs large amounts of water and forms gels that can be used in various processed foods. Moreover, it is a very interesting saccharide in that it is not decomposed by enzymes in the human body. However, few foods contain Konjac mannan. In this study, compared with control pound cakes, which contain soft wheat flour, egg, butter and sugar in a ratio of 1:1:0.75:0.75, the use of Konjac mannan gel in place of butter was examined. With 50% Konjac mannan substituted for butter (batter A), adequate physical properties and taste were obtained by increasing the amount of B.P. added to 3-4% of the weight of the wheat flour. Compared with the 28.9% water content of the control batter, the water content of batter A was 39.0%. Therefore every batter in this study was controlled to have a water content of 39.0%. Batter B consisted of 25% Konjac mannan and water, batter C contained equal amounts of Konjac mannan and egg white, and batter D only contained egg white; all yielded preferable pound cakes by increasing the amount of B.P. added to 3-4% of the weight of the wheat flour. The degrees of caloric intake suppression were about 21, 17, 14 and 14% for A, B, C and D, respectively.
Changes in the viscoelastic storage modulus (G') of a soybean flour dough (42% moisture content) during heating at constant temperature in the range of 60 to 190°C were followed by pressure rheometry (3.44 MPa). G' varied due to three simultaneous phenomena: initial softening, structuring and breakdown. The ratio G'f/G'0 measured at the end and beginning of the heating period started to increase at 110°C, reached a maximum at 150°C and decreased at higher temperatures. This result has been related to texture development and breakdown due to temperature in a thermoplastic extruder. A kinetic model was proposed to simulate the effect of the three underlying phenomena.
Fish meat emulsion was prepared from egg-yolk, very low-lipid sardine meat (which was prepared through grinding or suspending in weak alkaline solution), salad oil, and vinegar. The microstructures of the oil droplet surface and myofibrillar matrix were investigated. By Polytron homogenization, the myofibrils were shattered to a much smaller size in ground-meat emulsion, according to the original smaller fragment size. The network structure was formed by the myofilaments spread apart from the shattered myofibrils in the fish meat emulsion. The mesh size of this structure was smaller in the ground-meat emulsion than in the suspended-meat one and corresponded to the oil droplet size. In the suspended-meat emulsion, the oil droplet size was smaller at oil ratio 1.1 to sardine meat than at the ratio 1.6. In the non-fish conventional emulsion, the viscosity increase due to the dispersion of oil droplets to the egg-yolk matrix was not sufficient to prevent irreversible shear breakdown induced by coalescence. In fish meat emulsion, the network structure made of myofilaments showed a remarkable increase in viscosity and held the oil droplets tightly during the application of high shear rates to prevent the coalescence and exhibit a weak trend of thixotropy.
To propose an optimum packaging design and storage conditions for a tobacco product, which is composed of various solid components, a simulation model has been developed for predicting the amounts of water and flavor distribution among components during storage. The model is based on the adsorption equilibria of volatile vapors for the tobaccos, papers, filter and activated carbon as well as the permeation rate through the packaging films. The results of the simulation were in sufficient agreement with the experimental data to warrant the practical application of the model. The “Ethanol Adsorption Treatment” (EAT) for flavors with poor water solubility was confirmed to be remarkably effective when cigarettes were packaged with a film having a thin polyvinylidene chloride layer. When the products packaged with this film were stored under normal conditions for commercial marketing, such as inside a vending machine during the summer season, the water loss was predicted to be greater than the flavor loss, leading to a deterioration in the quality of the tobacco products. The optimum packaging designs and required conditions were obtained as follows: (1) the EAT for the filter tip, (2) storage conditions at lower temperatures, (3) selection of packaging film having a high vapor barrier against flavors.
A red wine was made from must consisting of dried roselle calyces, water, yeast extract, sugar, and NH4H2PO4. The pHs of wine samples were adjusted to various values within the range 2.5 to 4.0, or SO2 was added prior to yeast addition to give concentrations ranging from 0 to 250 mg/l, and the wines were stored at 25°C. After storage for 35 months, the pH of each wine was regularized, and the wines were then analyzed to determine their general composition and various red color parameters. There was little difference in general composition among the wines stored under different pHs and containing various concentrations of SO2. There were, however, appreciable differences in color density, color hue, and polymeric pigment color, but little difference in the wine color measured at wine pH and at pH 0.25, among the wines stored under different pHs. On the other hand, there were noticeable differences in all the above color parameters, except for color hue, among the wines stored under various SO2 concentrations. Wine color and anthocyanin color were more stable in wines stored at lower pHs or at lower concentrations of SO2, whereas the degree of contribution of polymeric pigment to wine color (at pH<0.5) increased with increasing storage pH and was lowest in the wines to which 100 or 150 mg SO2/l was added. Sensory analysis indicated that the addition of SO2 at 100 mg/l when bottling imparted the best overall quality to the roselle wines stored under the various conditions tested.
The bioavailability of iron in ferrous sulfate and in hemosiderin, prepared from pig liver in the laboratory, was evaluated in terms of the “hemoglobin regeneration efficiency” (HRE) and hematological indices. The anemia was induced in rats by feeding a casein-based, iron-deficient diet for 1 week and by withdrawal of blood from the retroocular vein. The anemic rats were fed for an additional 6 weeks the iron-deficient diet or the same diet supplemented with ferrous sulfate or hemosiderin at 6, 12, 18, 24 mg iron/kg diet. After 2 weeks, there was no significant difference in the HRE of the anemic rats fed with either hemosiderin or ferrous sulfate diets (31-55% for hemosiderin-fed groups against 28-52% for ferrous sulfate-fed groups). Blood parameters, levels of nonheme iron in the liver and spleen and iron contents in the liver, spleen, kidneys, heart and lungs of the rats fed with the hemosiderin diet were not significantly different than those of the rats fed with the ferrous sulfate diet. No significant difference was observed between the two experimental diets regarding the levels of available iron when assessed by the in vitro digestion method. The results indicated that hemosiderin is a good nutritional source of iron.
Miso (fermented soybean paste) had been shown to contain negligible or no Gly m Bd 30K, a major soybean allergen, by a sandwich enzyme-linked immunosorbent assay (ELISA). The fate of the allergen in miso with aging was systematically examined by ELISA and immunoblotting with a monoclonal antibody or sera from soybean-sensitive patients. The allergen in three types of miso (rice-koji, barley-koji and soybean-koji miso) was clearly shown to be rapidly digested as fermentation proceeded. These findings may provide useful information in the selection of these miso as one of the safe and hypoallergenic foods for soybean-allergic patients.
The protective effect of epigallocatechin gallate (EGCg) on paraquat-induced oxidative stress was determined in rats. Decreases in food intake, body weight gain, and liver triacylglycerol level, which were all caused by being fed a paraquat diet, were mitigated by supplementing EGCg in the paraquat diet. Blood and liver antioxidative enzyme activities were not significantly different among the control, paraquat, and paraquat+EGCg diets-fed rats. The liver thiobarbituric acid reactive substances, however, markedly decreased when the paraquat diet was supplemented with EGCg. These results indicate that EGCg acted in a preventive fashion against paraquat-induced oxidative stress.
Histological and physicochemical changes in the mantle muscle tissue of squid (Sepioteuthis lessoniana) during storage were studied. When raw squid mantles were broken parallel to the circular musculature, the rupture energy (RE) was significantly lowered along with the storage. In the case of breaking across the circular musculature, the RE was slightly lowered but the yield point (YP) in the stress-strain curve shifted to a larger strain during storage. In the case of heated squid meat, the YP shifted to a lower strain during storage. The electron microscopic observation of the muscle tissue of raw squid indicated that a number of voids appeared between the muscle bundles and the muscle fibers during storage, and after cooking, obvious detachment was observed between the muscle fibers and muscle bundles. No significant changes in the molecular sizes of major protein components (muscle fibril proteins) were observed, indicating that the muscle fibril proteins were not degraded.
For two types of “Shibazuke” samples matured at Ohara in Kyoto, the organic acid composition using HPLC analysis, Hunter's diagrams and sensory evaluation were investigated. One type has a good color tone (vivid magenta color) and is called a normal product (G-S). The other type has poor color and is called abnormal (P-S). The main organic acid component of both samples was lactic acid, and followed by acetic acid. Butyric acid, propionic acid and valeric acid were detected, especially in P-S. The pH of 4.2 in P-S is higher compared with the pH of 3.4 in G-S. Both samples are located on the purple color side in Hunter's diagrams. The difference in macroscopic evaluation between G-S and P-S was recognized as “perceivable” by the total color-difference of ΔE values of 17.2 N.B.S. P-S showed a significantly lower value in a sensory evaluation of flavor, but it did not smell putrid. The sensory evaluation value of sourness showed no significant difference, while that of color and total evaluation value were significantly higher in G-S.
In order to optimize production of fermented tomato juice, suitable lactic acid bacteria were selected, and the changes in constituents during fermentation were investigated. Fermentation and sensory evaluation showed that Lactobacillus bulgaricus IAM-1120 and L. helveticus JCM-1120 produced a preferable juice among ten strains of lactic acid bacteria. These two strains produced much lower diacetyl and acetoin than the other strains in tomato juice that contains a high level of citric acid. These results suggested that the minimal production of these compounds from citric acid as well as sugar was an important factor for selection of bacteria in preferable fermented vegetable juice. Moreover, a decrease in hexanal, a representative aldehyde in tomato juice, appeared to contribute to taste improvement after fermentation. The nutritional requirements for amino acids, vitamins and bases for the growth of the two bacterial strains were also characterized.
We examined the effect of tea extracts on immunoglobulin (Ig) production of mesenteric lymph node lymphocytes of Sprague-Dawley rats and found that various extracts suppressed the production of IgA, IgG, and IgM. In addition, the original extracts of green and black teas strongly enhanced IgE production, and their 102 or 103 times diluted samples exerted an inhibitory effect. Similarly, tea polyphenols having a triphenol group enhanced IgE production at 1 mM and inhibited it at concentrations below 100 μM. On the contrary, diphenolic epicatechin did not affect IgE production. Though all tea polyphenols exerted inhibitory effect on the production of IgA and IgG at concentrations above 10 μM, triphenolic compounds, such as epigallocatechin gallate, gallic acid and pyrogallol, exerted an enhancing tendency on IgA production at 0.1 μM. These results suggest that the Ig production-regulating activity of tea extract is partly due to tea polyphenols, especially those having a triphenol group.
Ovariectomized osteoporotic rats were divided into four groups: ordinary egg, vitamin D 2.5 μg fortified egg, vitamin D 10 μg fortified egg and a mixture of ordinary egg and authentic vitamin D. These samples were orally administered and vitamin D intakes of these groups were approximately 0.03, 0.19, 0.77 and 0.77 μg per day per rat. In comparison with the ordinary egg group, the vitamin D 10 μg fortified egg group was significantly higher in femur weight, femur length, tibia length, humerus length and ulna length. From histological photomicrographs of the rat's lumbar vertebrae, the average width of mineralized trabecular bone in the vitamin D 10 μg fortified egg group was larger than that in the ordinary egg group, and active osteoid formation was observed in the former group. Comparing bone parameters between the groups supplemented with the same amount of vitamin D either as egg or as authentic compound, they were significantly higher or slightly higher in the former than in the latter. These results indicated that sufficient amounts of vitamin D supplementation from egg were effective for bone growth even in ovariectomized rats.
Amberlite XAD-2 was selected as a suitable resin for column treatment to remove odorants in fish sauce samples. Amberlite XAD-2 could treat up to 700 times its volume of fish sauce. Headspace gas chromatographic analysis of treated and untreated samples revealed remarkable decreases in each class of volatile compounds studied: acids, 1/8-fold; aldehydes, 1/26-fold; ketones, 1/53-fold; alcohols, 1/2-fold; nitrogenous compounds, 1/5-fold; sulfurous compounds, 1/4-fold and miscellaneous compounds, 1/6-fold.
Loquat fruits (cv. Mogi) were harvested at three stages of ripeness (less-ripe, ripe, and full-ripe) and stored at 5°C to determine the optimal harvest ripeness for storage. During low-temperature storage, the weight of loquats at all three ripeness stages was decreased, whereas the weight losses showed no significant difference with ripeness. The decay of less-ripe fruit was worse than that of ripe and full-ripe fruits. Loquats underwent a significant decrease in titratable acidity (TA), malic acid and sucrose contents, while total sugars (TS), polyphenols, citric acid, succinic acid and fumaric acid contents did not vary greatly and resulted in a significant increase in TS/TA ratios during storage at 5°C. Development of skin color and carotenoids occurred progressively during the first 30 days of storage at 5°C and then did not vary significantly. Fructose and glucose contents of loquats increased during the first 30 days but after that appeared to decrease slightly. The sorbitol content of loquats increased steadily, while galactose decreased to a trace level during storage. Based on the data from this study, harvest ripeness greatly affected the quality of loquats at harvest as well as during storage. Ripe fruit showed superior storage capacity compared to fruits harvested at less-ripe and full-ripe stages.
Eleven chlorogenic acids, caffeoyltryptophan (CaT), and p-coumaroyltryptophan (CoT) in coffee beans (Coffea canephora var. robusta (Robusta) and C. arabica (Arabica)) and instant coffees on the market were analyzed by HPLC. Robusta beans contained more caffeoylferuloylquinic acids and CaT than Arabica beans. CoT was detected only in Robusta beans. The more intensely the coffee beans were roasted, the more all the chlorogenic acids decreased. CoT decreased the most slowly among phenols during roasting. Only instant coffees made of Robusta beans contained CoT. CoT becomes an indicator of Robusta beans.
Contents of antioxidative vitamins (ascorbic acid, β-carotene and tocopherols), dietary fibers, rutin and various minerals in box thorn leaves collected at different seasons (from mid May to mid October) were determined. The leaves contained 131-192 (mg/100 g) of ascorbic acid. The ascorbic acid content was maximum in June and minimum in July. The content of β-carotene was high (8.7-13.8 mg/100 g), but no α-carotene was found in the leaves. Among the tocopherols in the leaves, α- and β-tocopherol were the major components. α-Tocopherol was maximum in October (25.5 mg/100 g, on dry weight basis), and β-tocopherol, which is not an abundant type in nature, was high in July (27.2 mg/100 g), August (27.2 mg/100 g) and September (26.7 mg/100 g). The contents of dietary fiber (NDF, ADF, hemicellulose, lignin and cellulose) varied with the season. Differently from what has been known, box thorn leaves were not a rich source of rutin. Rutin was detected only in the leaves collected in May and October, and the contents were 0.45 and 0.38 mg/100 g, respectively. The leaves contained calcium (562-1316 mg/100 g), copper (0.26-1.20 mg/100 g), iron (9.42-21.77 mg/100 g), magnesium (403-657 mg/100 g), manganese (24.6-144.8 mg/100 g), potassium (1291-3046 mg/100 g) and zinc (3.2-24.3 mg/100 g). The contents of the individual minerals in the leaves varied greatly with the season.
A peptide mixture with a high Fischer ratio, which is defined as the molar ratio of Val+Leu+Ile to Phe+Tyr, was prepared from a whey protein isolate (WPI) by consecutively hydrolyzing with neutral and acid proteases and then by treating with SP-206 resin to adsorb the aromatic amino acids. The Tyr and Phe concentrations in the supernatant after adsorption on SP-206 resin were reduced by 8.3% and 14.2%, respectively. After this adsorption process had been repeated 7 times, the Fischer ratio of the peptide mixture was 9.0, while that of WPI was 4.7. The molecular weight, total average residue number and free amino acid concentration were 200-2,500, 2.6 and 22.3%, respectively.
Extensive sauce separation occurred in a white sauce containing bovine serum albumin (BSA) upon heating at 90°C; however, this occurred only slightly in the case where the BSA contained sulfhydryl groups which were modified with N-methylmaleimide (NMM) (modified BSA). SDS-PAGE analysis confirmed that BSA homopolymers were formed through disulfide bonds during heating and that α-and β-casein were not involved in the polymer formation during heating. Although the surface hydrophobicity decreased significantly upon heating in the case of BSA solution or the white sauce containing either BSA or the modified BSA, there was no effect of NMM modification on the decrease in surface hydrophobicity, indicating that the degrees of aggregation of both denatured BSAs were similar. On the other hand, the surface hydrophobicity did not change on heating in the case of white sauce alone. These results suggest that the network-formation of denatured BSA through disulfide bonds is responsible for the extensive sauce separation, while the aggregates of denatured BSA due only to noncovalent interactions cause only slight sauce separation.
To evaluate the influence of sugars (glucose, fructose, lactose) and aspartame on the uptake and transport of iron, we investigated iron uptake by monolayers of Caco-2 cells and the transport of iron from the apical to the basal chamber when Caco-2 cells were grown on polycarbonate membrane inserts in serum-free medium (ITS) (ITS; insulin, transferrin and selenious acid). Iron uptake in fructose and glucose was significantly greater than in lactose and the control groups (p<0.05). When the concentration of added fructose or glucose was increased from 2 μM to 20 μM, the uptake and transport of iron significantly increased. Aspartame 2 μM increased the iron uptake and transport rate.
The effects of freezing-thawing on the physical and chemical properties of shiitake were evaluated. It was observed that freezing-thawing did not cause apparent changes in the physical state of shiitake, although a characteristic sulfurous odor was generated. We demonstrated that lenthionine was produced during the thawing of frozen shiitake, and the amount produced varied with the conditions of both freezing and thawing. Among the conditions tested, freezing at —10°C and thawing at 37°C were found to be the most suitable for the production of lenthionine.