In this study, the strength of kamaboko gels heated by microwaves was investigated, and the change of elasticity of kamaboko gel during microwave heating was determined. The strength of gels made under direct microwave heating was low ; therefore, a new method using microwaves to set and to cook the gels was developed. It was found that the strength of two-step gels prepared by microwave heating had a value similar to gels heated using a water bath. Moreover, setting and cooking the gels using microwave heating took 11 minutes, which constituted an 80% reduction in production time compared to the boiling method.
Two types of lipids rich in arachidonic acid content were encapsulated using various saccharides as the wall material, and the oxidation processes of the encapsulated lipids were measured at 50°C and 12% relative humidity. One of the lipids contained arachidonoyl residue at a content of ca. 40%, and another was a structured lipid, the major component of which was 1,3-octanoyl-2-arachidonoyl glycerol. Microencapsulation effectively retarded their oxidation. In particular, among the tested saccharides, soluble soybean polysaccharide and gum arabic were the best two wall materials for the suppression of both lipids.
Sawdust and logs for shiitake cultivation were prepared from the same wood. Shiitake mushrooms were cultivated on the logs and on the sawdust substrate using the same mushroom seed. The proximate compositions, free amino acid and 5′-GMP contents of the harvested mushrooms were compared. Protein content in the sawdust-shiitake was significantly higher than that in the log-shiitake. The total free amino acid content was higher in the sawdust-shiitake. Sweet and umami components were also higher in the sawdust-shiitake, as was the bitter component. However, the 5′-GMP content was slightly higher in the log-shiitake.
To gain insight into the process of retronasal olfaction, flavor release from skimmed milk and full fat milk (containing 3.75% fat) was investigated using a model mouth system with a screw plunger. Large differences were determined in the quantity of flavor released using two different methods : with screw plunger movement, which represents “retronasal” flavor release, and without the screw plunger, which represents “orthonasal” flavor release. The screw plunger motion accelerated the release of diacetyl and 2-heptanone in both skimmed and full fat milk. The amount of diacetyl released was not influenced by the fat content of the milk in either case (with or without screw plunger operation), while the amount of 2-heptanone released was lower in full fat milk both with and without screw plunger motion. The influence of fat content on the amount of flavor released was explained by the lipophilicity of the flavor components, and mass transfer also contributed to release of the hydrophilic flavor compound.
Instrumental and sensory analyses were carried out on sesame-flavored dressings to identify the odorants affecting their perceived quality. The sampling of the odor-active compounds was performed by simultaneous steam distillation extraction (SDE) and solid-phase microextraction (SPME). The odor intensity and character of the compounds were evaluated and quantified using gas chromatography/olfactometry (GC/O). The GC/O and the sensory data were processed and analyzed on the basis of food kansei model. Seven perceptual factors affecting the aroma and flavor were abstracted by principal component analysis (PCA) of the sensory data. According to the percentage of contribution, the first perceptual factor of “roast and spicy” was identified as a key factor. The correlations between the odorants and the “roast and spicy” factor clarified the importance of sulfurous compounds. Four sulfurous compounds were identified as butanethiol, prenyl mercaptane, 2-methyl-3-furanthiol and dimethyl trisulfide.
In the present study, to develop a new, soft and nutritious peanut product (P-tempeh) to encourage their consumption, peanuts were steamed and were fermented with Rhizopus oligosporus. P-tempeh was suggested to have more free fatty acids than ordinary peanuts and to be readily digestible. Frying and roasting proved to be the preferred ways to prepare P-tempeh. Fried, roasted or steamed, P-tempeh was rated as being more flavorful than soybean-tempeh (S-tempeh), but had 1.7 times the calorific content of soybean tempeh. However, when P-tempeh was prepared with peanuts substituted with 20% quinoa (P8Q2-tempeh), the calorific content decreased to 1.2 times that of S-tempeh. While this made it less preferable in comparison to P-tempeh, it remained comparable with S-tempeh. When P8Q2-tempeh was pre-seasoned with miso, taste scores improved and were similar to those of P-tempeh. Based on these results, when prepared properly, P8Q2-tempeh tastes good, and is a very nutritious and digestible new food source that holds considerable promise.
A system using immobilized enzyme according to Oki et al., [Biol. Pharm. Bull. 23(9) 1084-1087 (2000)], which mimics the small intestinal membrane, was applied to the screening of several kinds of vegetables, fruits and herbs in terms of their inhibitory effects on α-glucosidase (AGH). AGH was partially purified from hog intestinal membrane by salting out, followed by immobilization on CNBr-activated Sepharose 4B as a matrix. As substrate, p-nitrophenyl-α-D-glucopyranoside (PNPG) was employed, producing p-nitrophenol (p-NP) by enzymic hydrolysis. Seven vegetables (Japanese radish, cabbage, onion, Chinese cabbage, tomato, cucumber, and carrot), 5 fruits (mandarin, apple, watermelon, melon, and grapefruit) and 4 herbs (Italian parsley, rucola, mache, and dill) were subjected to evaluations of the inhibitory effect on AGH. All of the test samples exerted an inhibitory effect on immobilized AGH (iAGH). Raw Chinese cabbage and boiled tomato among vegetables, mandarin among fruits and dill among herbs exerted the strongest inhibitory effect on iAGH.
The physicochemical properties of starches isolated from eight potato cultivars were analyzed. The phosphorus and amylose contents and median granule size, as well as the rapid visco-analyzer (RVA) pasting properties, differential scanning calorimetry (DSC) gelatinization properties, and gel firmness, were differed significantly among the starch samples tested. Korean-style cold noodles were prepared from wheat flour : potato starch (1 : 1) blended flours with alkali and salt solution using a specific wheat flour and one of the 8 potato starches. Variations were observed in the textural properties of the cooked noodles were measured with a rheoner for each of the starch samples used. The phosphorus and amylose content, RVA pasting properties, DSC gelatinization properties, and gel firmness did not affect the elasticity of the noodles. In contrast, the granule size was seen as the most important factor for determining the elasticity of the cold noodles, and Konafubuki, Irish Cobbler, Kitamurasaki, and Toyoshiro starches with relatively small granule size appeared to be desirable for making cold noodles. The firmness of the noodles was not affected by any of the potato starch properties.
A micellar electrokinetic capillary chromatographic (MEKC) method was developed for the two major polymethoxylated flavones, nobiletin and tangeretin, using a fused-silica open-tubular capillary in a 70% methanol extract from citrus albedo tissue. A MEKC separation buffer (pH 7.0), consisting of 32mM sodium dodecyl sulphate (SDS), 20mM sodium dihydrogen phosopate, 12mM disodium tetraborate and 20% methanol, was selected in order to optimize separation conditions. The order of elution was nobiletin and tangeretin. Of the 46 species and cultivars in the Citrus genus, 17 were assayed for nobiletin and/or tangeretin in this study. The Acrumen and Pseudofortunella sections, classified by Tanaka, were found to contain the highest flavone concentrations.
To study the anti-tumor activity of sea cucumber extracts, human colon adenocarcinoma Caco-2 cells were exposed to hot water extract of sea cucumber. Morphological changes with apoptotic bodies were observed in the cells treated with the extract. We demonstrated the induction of apoptosis using phosphatidylserine translocation (APOPercentage Assay kit), terminal deoxynucleotide transferase-mediated dUTP-biotin nick-end labeling (TUNEL), and DNA fragmentation observed as DNA ladder. These results show that apoptosis was induced by a high molecular weight fraction in a dose dependent manner. These data suggest that water soluble and high molecular weight compounds from sea cucumber might exhibit anti-tumor activity by triggering apoptosis. The apoptosis-inducing activity may contribute to cancer chemopreventive effects of sea cucumber.
We studied the effects of cryofocusing on the resolution of volatile components in solid-phase microextraction (SPME). Retention times, resolutions and peak areas estimated using cryofocusing were compared to those observed without cryofocusing. The resolution and peak areas with cryofocusing were found to be greater than those obtained without cryofocusing. Hence, SPME cryofocusing is effective in trace analysis of the volatile components in orange juice.
In this study, we analyzed the influence of proteins and polysaccharides on the viscous properties of mucilage extracted from Dioscorea opposita Thunb. (Chinese yam). The viscosity of the mucilage was greatly reduced by treatment with protease or mannanase, although not by treatment with cellulase. These results show that the interactions with mannan of certain soluble proteins in the mucilage play an important role in its viscosity, so we identified the major soluble proteins present. Chinese yam mucilage contained at least nine types of major soluble proteins, some of which showed a high percentage of identity with dioscorin, mannan-binding lectin and other functional proteins in the N-terminal amino acid sequence. From these findings, it was suggested that the viscosity of Chinese yam mucilage may be caused by interaction between mannan and soluble proteins such as mannan-binding lectin.