Water that maintains its liquid state in the temperature range from 100°C to 374°C is called subcritical water, compressed hot water or pressurized hot water. This type of water has unique properties compared to ambient water. One is a low relative dielectric constant and another is a high ion product. Due to these properties, this water can be used to extract functional substances from natural resources. In this article, the application of subcritical water for the extraction of substances from agricultural products or their wastes is reviewed.
This study was intended to build 3D FEM geometry models of actual ‘Fuji’ apples by digitizing their surfaces, and to determine elastic modulus by FEM simulation based on the F-D curves of radial compression test from a point on apple equator. Also, the general protocol of ASAE S368.4 for predicting the apparent modulus of elasticity and the maximum contact stress for convex-shape food materials was evaluated for its appropriateness. The model apple for FEM analysis was composed of approximately 35,000 geometry elements that closely resemble the surface of an actual apple. Through FEM simulation, the average elastic modulus of 7.732 MPa was obtained at the loading condition of 0.5 BP, which was 8.3% smaller than the average apparent modulus of elasticity predicted by the ASAE standard. The maximum Von Mises stress at the points of initial contact with the compression target plates evaluated by FEM simulation was about 37% smaller than the maximum contact stress determined by the ASAE standard, and a poor correlation was found between the results of the two methods. These results could be explained by that a whole apple, in general, has an anisotropic structure with many complex and small curvatures, has flesh texture bonded biologically, and is covered with more elastic membrane shell which contributes to prevent dehydration during compression.
The mechanical properties of six cabbage varieties harvestable in May in Miura Peninsula, Japan, were measured by subjecting strap-shaped specimens to tensile testing. The fracture properties greatly differed with direction of veins and cultivars. No single parameter characterized the physical properties of cabbage varieties. The mechanical variables in tensile tests conducted parallel and perpendicular to the veins were subjected the principal component analysis. The six cultivars were evidently categorized into three groups. Intermediate varieties were separated into two; one resembled to the Winter type, which is suitable for shredded cabbage, and the other was similar to the Spring type.
Strains of wine yeast are differentiated based on their ability to ferment grape juice. To advance enology and food technology, many efforts have been invested in the detection and breeding of yeast with high fermentation ability. In this study, we investigated the enological character of 96 yeast strains isolated from spontaneously fermented botrytized grape juice with a high sugar level(35%). The 96 isolates produced wines with ethanol concentrations of 6.7-14.9% (average, 10.9%) from grape juice containing 35% sugar. Among these isolates, KN-35 strains produced 15.8% and KN-94 strains produced 16.2% ethanol in botrytized Kerner grape juice after 50 days of fermentation. Furthermore, we observed that several aroma compounds and higher alcohols present in KN-35- and KN-94-fermented wines were similar to those found in popular wines. The results of this study demonstrated that the KN-35 and KN-94 yeast strains were useful as a starter culture in wine-making, particularly for the fermentation of botrytized grape juice.
In this study, we examined the effects of Spirulina platensis, a multicellular filamentous blue-green algae currently used world-wide as a food supplement, upon acute and subchronic treatments to rodents. For short-term treatment, no signs of toxicity were observed within 7 days after feeding male Swiss mice at the high dose of 30 and 10 g/kg body weight of fresh and dried S. platensis, respectively. For the subchronic toxicity study, two separate experiments were also performed to evaluate both forms of S. platensis. In each experiment, four groups of six Sprague-Dawley male and female rats were given fresh or dried alga at various doses by feeding daily for 12 weeks. In all instances, the consumption of algae showed no effect on behavior, food and water intake, growth or health status of these animals during the course of this investigation. The values in clinical chemistry monitored throughout the study period did not reveal significant differences between the control and treated groups. In addition, post-mortem examination found no abnormalities in the gross findings. Our results thus demonstrate for the first time that short-term and long-term consumptions of S. platensis, up to high feeding levels, did not produce any adverse effects in experimental animals.
The characteristic aroma compositions of Citrus junos Sieb. ex Tanaka (yuzu) cold-pressed peel oil were studied by both instrumental and organoleptic methods. The samples were obtained from 5 popular yuzu production districts: Kochi, Tokushima, Ehime, Oita and Wakayama prefectures of Japan, at common harvesting periods early, middle and late November. Of 174 compounds detected, 67 compounds were identified and quantified. The compositional and olfactometry profiles of yuzu essential oils from Kochi were compared with those from the 4 other origins. The ratio of monoterpene to sesquiterpene hydrocarbons also presented the characteristic citrus aroma profile. Principal component analysis based on frequency of descriptive notes was carried out. Some difference was identified between the samples from Kochi and other origins, even those harvested in the most common harvesting period. In general, the profile of yuzu from Oita and Wakayama was approximately the same as that from Kochi.
Significant physicochemical properties of Danish pastry samples have been identified to establish a methodology for optimally designing product with maximized palatability, using the food kansei model (Ikeda et al., 2004). A series of procedures for textural measurements and analyses has been proposed for the samples, as follows: 1) fixing linear ranges in which force is proportional to strain, and 2) identifying the intrinsic textural attributes from viscoelastic moduli obtained by creep tests. Analysis of variance was used to select food kansei variables at the level of 5% among the instrumental and sensory data. Multiple regression analysis was employed to correlate palatability with the rotated principal component scores of perception. The optimal values of ingredients and physicochemical properties were consequently determined by multivariate-spline and regret function. The results of validation by cluster analysis indicated that the maximum height, density, water and oil contents, instant elasticity E0 , and permanent viscosity ηN were the optimal combination for describing physicochemical properties of Danish pastry samples.
Glucosinolates, precursors of isothiocyanates, are present in cruciferous vegetables such as the turnip (Brassica rapa L.). Glucosinolates are usually broken down through hydrolysis catalyzed by myrosinase released from damaged plant cells. Glucosinolates and their breakdown products, in particular isothiocyanates, have long been known to have various pharmaceutical benefits, including anticarcinogenic, antimicrobial and antioxidant properties. In this study, quantitative analyses of isothiocyanates and total glucosinolates in turnip, which was divided into three parts, were performed by UV-spectrometer, GC and GC/MS. Total glucosinolates showed no significant differences among different parts of turnip. However, the amounts of 3-butenyl and 4-pentenyl isothiocyanates in turnip leaf were higher than those in other parts. β-Phenylethyl isothiocyanate, abundant in the peel, showed the highest content in turnip. In addition, β-Phenylethyl isothiocyanate inhibited the growth of human-derived hepatoma cell line (HepG2) in a concentration-dependent manner (IC50 value of 24.5 μM), assessed by the MTT method. β-Phenylethyl isothiocyanate also exhibited antimicrobial activity against food-borne pathogens Vibrio parahaemolyticus, Staphylococcus aureus and Bacillus cereus. In particular, minimum inhibitory concentration (MIC) against Vibrio parahaemolyticus was the most efficient, at 100 μg/ml. These results suggest that the major isothiocyanate in turnip is β-phenylethyl isothiocyanate. Furthermore, β-phenylethyl isothiocyanate may have anticancer effects and antimicrobial properties against food-borne pathogens.
Roselle (Hibiscus sabdariffa L.) is known to possess strong antioxidative capacity mainly due to its high content of anthocyanins and ascorbic acid. This study aimed to elucidate the ratio of contribution of these compounds in Roselle extract towards superoxide anion scavenging capabilities through analysis using electron spin resonance (ESR) coupled with the hypoxanthine/xanthine oxidase system and DMPO spin trapping technique. The ESR analysis indicated that the IC50 of Roselle extract against superoxide anion was 0.25 mg/ml. After depleting the ascorbate in Roselle extract (0.25 mg/ml) with ascorbate oxidase, the remaining superoxide anion scavenging capacity was determined to be 30.5%, which revealed that ascorbic acid substantially facilitated the scavenging process. By both HPLC and LC/MS analyses, the major active anthocyanins in Roselle crude pigments were identified as delphinidin-3-sambubioside (71.2% of total peak area), delphinidin-3-glucoside (8.7% of total peak area) and cyanidin-3-sambubioside (16.1% of total peak area). Approximately 80% of the superoxide anion scavenging capacities of these anthocyanins was from delphinidin-derivatives (delphinidin-3-sambubioside and delphinidin-3-glucoside); the other 20% was from cyanidin-derivative (cyanidin-3-sambubioside).
Horseradish (Armoracia rusticana) is a traditional herb used mainly in Asia, Europe, and North America. Processed food products that include horseradish as an ingredient have been developed and produced. Here, we report on the detection of multiple myrosinase genes of horseradish that closely resemble each other. For amplification of each myrosinase gene, a primer was designed and subjected to polymerase chain reaction (PCR) to obtain the horseradish DNA fragments (ca. 500 bp). PCR using the myrosinase gene primers obtained no corresponding DNA fragments of other species, including wasabi, radish, spinach, and pea. This amplification technique is therefore applicable for the specific detection of horseradish for processed food products.
The quality of brined Chinese cabbage after washing (tap water, 100 ppm of calcium hypochlorite, or electrolyzed acid water) followed by package (40 μm or 100 μm LDPE), was investigated at 20, 10, 5, and 0°C for 5, 10, 20, and 20 days, respectively. At all treatments, pH, vitamin C, and reducing sugar were gradually decreased in brined Chinese cabbage washed using either calcium hypochlorite or electrolyzed acid water compared to tap water. Total cell counts initially decreased by the treatment of both hypochlorite calcium and electrolyzed acid water and then slowly increased during a storage period. The 100 μm of LDPE package seemed to be more useful in maintaining the quality of brined Chinese cabbages than the 40 μm one at all treatment groups. The use of calcium hypochlorite coupled with 100 μm LDPE was most effective to maintain product quality resulting in the best overall sensory acceptability.
The contact plate is a medium for simple microbial testing in which microbes are sampled by directly contacting its surface with the test surface. In general, sampling may be difficult when the conventional agar-based contact plate is used for sampling from uneven test surfaces. Additionally, a wet trace of nutrient components may be left on the test surface after sampling. In order to solve these problems, we prepared contact plates by the combined use of native gellan gum and agar as solidifiers. Compared to the conventional agar-based medium, the gellan gum and agar-mixed contact plate exhibited better performance of sampling from uneven test surfaces, owing to its relatively softer and more deformable medium gel. These results indicate that media prepared with native gellan gum and agar are suitable for contact plates.
In this study, the inhibitory effect of hop water extract (HWE) on influenza A virus infection was examined by the hemagglutination inhibition (HI) test, inhibition of virus growth in MDCK cells (in vitro) and the morbidity and mortality of mice after nasal infection of the virus (in vivo). HWE significantly inhibited the hemagglutination of influenza A virus at a total polyphenol concentration of 0.6 mg/ml. HWEpretreated influenza A virus could not infect MDCK cells. The 50% tissue culture infectious dose (TCID50) of HWE was 28.6 μg/ml. Furthermore, a treatment of 50 mg/ml of HWE for influenza A virus significantly inhibited the mortality of mice against nasal infection with influenza A virus. HWE exerted an inhibitory effect against viral infection by inhibiting the binding of hemagglutinins of Flu and the sialic acid-containing glycoproteins of epithelial cells. HWE seems to be a promising agent to prevent the influenza A virus infection.
Bond dissociation enthalpies (BDEs) for phenolic constituents from Tessaria integrifolia RUIZ. et Pavon and Piper elongatum VAHL. have been calculated using the semi-empirical molecular orbital (MO) method (PM3). A significant correlation between the BDE of the phenolics and their radical-scavenging effect was found. The BDEs evaluated by semi-empirical MOs can provide a convenient and useful clue for assessment of the antioxidative activity of phenolics.