A procedure for determining the viscoelastic properties of apple flesh has been proposed based on compression tests and FEM optimization. Short-term simple compression tests and long-term relaxation tests were performed with cylindrical specimens of apple flesh to measure mechanical properties, and the viscoelastic behavior was predicted using FEM optimization models. Through short-term optimization, the elastic modulus and Poisson's ratio were determined by comparing two kernel functions based on 1) shear only and 2) shear and bulk terms. Long-term stress-relaxation behavior of the specimen was reasonably predicted by two FEM optimization steps within 3.8 % error. The FEM optimization algorithms developed in this research might be applied to determine the viscoelastic properties of bio-materials and also to predict mechanical behavior of these materials under various loading conditions.
Although the viscosity of aqueous solution of high methoxyl pectin is known to increase drastically when sugars coexist, the detailed mechanism for the increase in viscosity was not fully understood. Therefore, the viscosity of citrus and apple pectin solutions with various sugars compositions was measured with temperature varying from 5 to 40°C to analyze the intermolecular interactions among pectin molecules. For single-composition pectin solutions, the activation energy for viscosity, Ea, increased from 17.5 to 31.9 kJ/mol with an increase in pectin concentration up to 2% for the case of citrus pectin, reflecting the increase in pectin-pectin interaction. For pectin solutions with coexisting sugars, Ea increased more with increasing sugar concentration. When compared at the same water activity, the increase in Ea is also dependent on the type of sugar. Sugars with stronger solvent-ordering activity produced greater increases in Ea. These results suggest that sugars increase the pectin-pectin interaction both through their own hydration effect, which enhances the hydrogen bonding among pectin molecules, and through the solvent-ordering effect to enhance the hydrophobic interaction.
Enhanced production of bacteriocin by Staphylococcus sp. NPSI 38 (NPSI 38) using koji extract medium was investigated. The bacteriocin produced by NPSI 38 in MRS medium was found to be effective for inhibiting the growth of Lactobacillus hilgardii NBRC 15886T, one of the representative hiochi-bacteria. In cultivations using test tubes without pH control, meat extract and Polypepton were effective for bacteriocin production by NPSI 38 with 10%(v/v) koji extract medium. When the koji extract medium supplemented with hydrolyzate of a rice protein preparation was used instead of meat extract and Polypepton, NPSI 38 produced 160 U/ml of bacteriocin in the cultivation with pH control, which was almost as high as that (156 U/ml) observed in cultivation using MRS medium with pH control. When the cells of L. hilgardii NBRC 15886T collected at logarithmic growth and stationary phases were inoculated into fresh modified MRS medium with 11 U/ml of the bacteriocin, negligible cell growth was observed, irrespective of different growth phases of cells inoculated. Little or no increase in cell concentrations in the media containing bacteriocin showed that the action of the bacteriocin produced by NPSI 38 was bacteriostatic against the hiochi-bacterium.
A tubular ice system is effective for the scale-up of progressive freeze-concentration. The effective partition coefficient, K, as an index for the effectiveness of progressive freeze-concentration, is defined by the ratio of solute in ice and liquid phase. K is dependent both on the ice crystal growth rate and the mass transfer coefficient at the ice-liquid interface, as described by the concentration polarization model. The limiting partition coefficient, K0, corresponds to K at the infinitesimal ice crystal growth rate and/or infinite mass transfer at the interface. K0 is an important process parameter for progressive freeze-concentration. A method is proposed for determining K0 experimentally for a tubular ice system. K0 increased with increase in the concentration of solute, which suggests that K0 is not determined by the equilibrium process but by the nonequilibrium process at the ice-liquid interface.
We examined the effects of orally administered flavonoids isolated from buckwheat (Fagopyrum esculentum Moench) sprouts in restrained mice. These flavonoids have been shown to have antioxidant activities in vitro. A propylene glycol (PPG) or flavonoid (mixture of rutin, orientin, isoorientin, vitexin, and isovitexin in PPG) solution (100 mg/kg body weight) was administered to mice intragastrically once per day for three days, after which the mice were restrained for 24 h. Unrestrained mice were administered PPG solution with or without free access to feed and water. Restraint stress induced increases in plasma corticosterone, plasma glutamic-oxaloacetic transaminase activity, and the amount of thiobarbituric acid-reactive substances in plasma and liver tissues. In contrast, these variables were suppressed in the mice that were administered flavonoids. These results suggest that flavonoids from buckwheat sprouts have in vivo anti-stress effects against the reactions induced by immobilization in mice.
To seek out a cheap source of dietary polyphenols and antioxidants along with anti-amylase and anti-glucosidase activities, ethanol extracts of eleven cheap Bangladeshi fruits were investigated. The extracts were also examined for anti-allergic activity using rat peritoneal exudate cells exposed to the calcium ionophore A23187. Phyllanthus emblica (emblic myrobalan) had the highest total polyphenol content (339 mg gallic acid equivalent (GAE)/g), followed by Syzygium cumini (Indian blackberry; 192.3 mg GAE/g), and Aegle marmelos (wood apple; 53.7 mg GAE/g). P. emblica, and S. cumini also exhibited the most potent DPPH radical scavenging activity, with an IC50 of 2.1 and 8.6 μg/mL respectively. These extracts also showed promising reducing powers with P. emblica having the greatest such activity (optical density (O.D.) 1.66), followed by S. cumini (O.D. 1.34), at a concentration of 0.2 mg/mL. The extracts of Artocarpus heterophyllus (jackfruit) and S. cumini showed promising chelating activities. At a concentration of 1 mg/mL, Dillenia indica (chalta) showed the highest inhibition of α-amylase activity (60%), and A. marmelos, D. indica, P. emblica, Spondias dulcis (hog-plum) & S. cumini completely inhibited α-glucosidase activity (100%). Apart from A. heterophyllus, D. indica and Phyllanthus acidus (star-gooseberry), all other extracts inhibited the release of histamine from the peritoneal exudate cells, with S. cumini having the strongest effect. These fruits therefore have activities beneficial to physiological health.
The objective of this study was to develop a new approach that can be used to estimate the in-mouth release characteristics of odorants in chewing gum. This technique, called the “Retronasal Flavor Impression Screening System (R-FISS),” is based on a modified dynamic headspace gas sampling technique. By application of the R-FISS technique, the in-mouth release characteristics of odorants during the chewing of gum was indicated by the peak area ratio, which was calculated by comparing the peak area for 10 min to the peak area for 1 min, of each odorant exhaled from the human nose. In addition, a good overall regression coefficient was found for the correlation between the peak area ratios of each odorant in the model chewing gum obtained by R-FISS and the retention indices on a polar stationary phase GC column (DB-Wax). Therefore, the in-mouth release of odorants in chewing gum seems to be capable of being predicted by their RIs on a polar stationary phase GC column (DB-Wax), and these results appear to suggest that two parameters (vapor pressure and hydrophobicity/hydrophilicity) are the key factors for determining the in-mouth release of odorants from chewing gum.
We investigated the possible anti–influenza virus function of Goishi tea, which is a Japanese traditional microbial fermented tea, in in vitro and in vivo tests. We found that Goishi tea hot water extract (GTE) inhibited hemagglutination caused by influenza A/ Puerto Rico/ 8/ 34 (PR8, H1N1) and influenza A/ Guizhou/ 54/ 89 (Guizhou, H3N2) viruses, viral growth in Mardin-Darby canine kidney (MDCK) cells caused by PR8, and viral infection of mice caused by nasal inoculation of PR8. Furthermore, we investigated the functional fractions of GTE and found that a high-molecular-weight fraction of GTE inhibited viral adsorption to MDCK cells and that low-molecular-weight fractions inhibited subsequent stages of infection, such as viral invasion, genomic multiplication, and release, after adsorption. These results indicate that GTE exerts an inhibitory property against influenza virus infection by inhibiting various stages of infection.
The lactic acid fermentation of instant Chinese noodle sheet by Lactobacillus plantarum NRIC 0380 changed the noodle quality as evaluated by texture and sensory tests. This interesting change was induced by only a short 2-h fermentation time, however the noodle quality subsequently degraded with prolongation of the fermentation of up to 24 h. SDS-PAGE analysis of proteins in the noodle sheet indicated no change in proteins extracted from the 2-h fermented noodle sheet compared to non-fermented noodle sheet. In contrast, native-PAGE analysis showed a shift in molecular weight of gluten proteins, with those extracted from the 2-h fermented noodle sheet having a higher molecular weight than those from non-fermented noodle sheet. These results strongly suggested a conformational change of gluten proteins in the noodle sheet caused by the short 2-h fermentation. The 2-h lactic acid fermentation decreased the pH from 8.5 to 7.5, but gluten proteins extracted from noodle sheet made with the addition of lactic acid to adjust the pH to 7.3 did not show this increase in molecular weight. Thus, the change from native state of gluten proteins does not seem to be induced by the presence of the lactic acid itself but by other factor(s) associated with lactic acid fermentation. On the other hand, the reduction of noodle quality by prolonged fermentation for up to 24 h seems to induce degradation of albumin and globulin proteins as revealed by SDS-PAGE analysis and also the change in the native state of gluten proteins as detected by native-PAGE analysis.
The possibilities and limitations in the food kansei model (Ikeda et al., 2004) have been revealed through a case of product development for a ready-to-eat cup-soup that had achieved two-billion-yen sales in 1993. Based on the pre-specified product concept, twelve samples were selected to extract twenty descriptors for the sensory evaluation of the product image, and ten descriptors for that of the quality characteristics. All the sensory scores were summarized by principal component analyses (PCA). The quality characteristic evaluation corresponded to the route of perception in the model, and the image evaluation, the route of cognition as well as the interrelation between the two routes. The model can ensure the marketing success of the specified processed foods only if consumer needs can be precisely incorporated into the initial product concept.
The present study seeks to investigate the bleaching of palm oil with activated plantain peel ash (APPA). Concentrations of β-carotene, iron, copper, lead, and phosphorus in the crude (unbleached) and bleached palm oil were evaluated. The peroxide value, anisidine value, acidity and colour of the oils were also determined. The objectives were to assess the bleaching performance of the APPA, compare the performance of APPA with that of a commercial natural earth (Pure-Flo Neutral B-80) and investigate the effects of particle size of APPA and APPA/oil ratio on the bleaching performance of APPA. The results indicated that APPA significantly decreased all the investigated characteristics apart from acidity. Results also indicated that Pure-Flo Neutral B-80 slightly performed better than APPA under the same experimental conditions.
A double-blind, placebo-controlled clinical trial was performed to investigate the efficacy and safety of 12-week intake of honeybee-collected pollen lump extract (HPLE)-supplemented food in 47 patients with benign prostatic hyperplasia (BPH). The participants were randomly assigned to 3 study food trial groups: a placebo group (0 mg HPLE per day); a lower-dose group (160 mg HPLE per day); and a high-dose group (320 mg HPLE per day) (Groups P, L, and H, respectively). Outcome measures were the change during the 12-week intervention period in subjective symptom scores and 2 urodynamic parameters, maximum flow rate (Qmax) and residual urine volume. Qmax values were significantly increased in Group H (P<0.05) but not in Groups L or P. While residual urine volume was significantly increased in Groups L and P (P<0.05 each), the level in Group H decreased, although the difference between Groups H and P did not reach statistical significance (P=0.052). No HPLE-related health hazards or laboratory abnormalities of clinical significance were encountered.
Microwave-assisted hydrodistillation (MAHD) has recently been attended for the extraction of essential oils from medicinal plants/herbs. In this study, MAHD was investigated for the extraction of essential oils from two genotypes of savory (Satureja hortensis, so-called summer savory, and Satureja montana, so-called winter savory). Three levels of microwave power (220, 440 and 660 W) were selected for the extraction. MAHD resulted in a shorter extraction time compared to that in HD. Total extraction times at 660 W microwave power was 180 min for S. hortensis and 90 min for S. montana. The extraction yield obtained by MAHD was almost equal to that obtained by HD (3.1%, w/w, for S. hortensis and 0.7% for S. Montana). Extraction was more efficient at higher power levels.
The mechanism for the beneficial effects of vitamin C (L-ascorbic acid, AsA) on the quality of the heat-induced fish gel, kamaboko, has been proposed by Nishimura et al. to involve the production of thiyl radical (S·). The generation of S· in myosin by the superoxide anion radical (O2-), produced by the photoactivation of riboflavin, was then examined by electron spin resonance spectroscopy coupled with spin-trapping. Consequently, the production of S· was observed. This generation of S· in myosin was inhibited by the addition of 100 units (u)/ml superoxide dismutase (SOD), whereas heat-inactivated SOD, catalase (1,200 u/ml), and heat-inactivated catalase did not suppress the generation of S·. These results suggested that the generation of S· in myosin occurred due to the presence of O2-.