Coffee is the most popular drink in the world and coffee intake may be a risk factor for gastroesophageal reflux disease (GERD), which is a common disorder and its worldwide prevalence is increasing. However, the effect of coffee on GERD remains to be fully elucidated. The relationship between GERD and coffee consumption is not clear given the existing literature, whose results are diverse and contradictory. Existing systematic investigations are not adequate and further well-designed prospective studies are needed to clarify the effect of coffee on GERD.
The main objective of this study was to investigate the influence of different commercial wine yeast strain combinations on wine varietal aroma and glutathione concentration. Four combinations of yeast strains were selected to produce Sauvignon Blanc wine under controlled conditions. The concentration of volatile thiols and methoxypyrazines in produced wines was quantified using GC-MS and the concentration of glutathione during fermentation was monitored and quantified using HPLC-FLD. Sensory analysis of wines was performed by a group of experienced wine assessors. The results indicated that the yeast strain combinations differed significantly in terms of their ability to release volatile thiols and to preserve glutathione levels, but had no impact on methoxypyrazine concentrations. In accordance with the chemical composition of wines, significant differences were found in their sensory quality. It can be concluded that the selection of an appropriate yeast strain combination for alcoholic fermentation presents the potential to greatly modulate wine aroma.
The drying conditions of spaghetti affect its properties, such as appearance, hardness and water sorption. The dried spaghetti is eaten after cooking. In this context, the water sorption kinetics of spaghetti dried under different conditions was measured at various cooking temperatures. The spaghetti was characterized by the maximum temperature during the drying: 50°C, 70°C and 85°C. The water sorption processes of the spaghetti at any cooking temperature could be expressed by an empirical kinetic equation of the hyperbolic type, and the equilibrium moisture content and the initial rate of water sorption were estimated, taking the loss of spaghetti mass during cooking into consideration. The loss of spaghetti mass was lower for spaghetti dried at higher temperature. Maximum temperature affected the change in the enthalpy of water sorption in the temperature region to a greater degree than the gelatinization temperature of starch in the spaghetti, while it had no effect on the activation energy for the initial rate of water sorption.
The objective of this study was to evaluate the effect of low erucic acid content mustard seed on model sausage type products with regards to oxidative stability, by measuring oxidation-reduction potential, color, heme iron content and fatty acids composition during storage at 4°C. Investigations were carried out on model sausage type product produced from pork meat (m. biceps femoris) and fat. The addition of ground mustard seed at the level of 0.2 and 0.5% was not effective in lowering the oxidation-reduction potential (ORP) in model meat product. Model sausage type product samples with added mustard seed showed, in general, higher amounts of heme iron and the amount of n-3 fatty acids compared to the controls. Results suggest that the addition of mustard seed should be considered as a good method to improve oxidation stability and functional values of muscle foods.
Humidified baking was investigated in the light of producing breads envisaged to have better quality and freshness. Open bread loaves were prepared using the straight dough method where baking was performed with or without humidity at three levels of temperatures of 185, 195 and 205°C, and baking times of 25, 30 and 35 min. Baked breads were evaluated by measuring its crust color and thickness, and bread crumb moisture content and firmness. Humidified baking has no significant effect in enlightening bread crust color (P > 0.05) but significantly reduced the crust thickness (P < 0.001) and increased the initial moisture content (IMC) of bread crumb. The higher IMC of bread crumb led to a higher final moisture content (FMC) of bread during storage and these helped to reduce the firming rate of bread during a 96 h storage especially for the lower baking temperatures and times. Significant differences (P < 0.001) were observed on crust color and thickness, and bread crumb moisture content and firmness as effect of baking temperature and time.
The composition of volatile components in 18 Citrus Archicitrus species, 17 Citrus Metacitrus species and two Fortunella species, according to the classification system established by Tanaka, was investigated using headspace gas chromatography-mass spectrometry. The composition of 48 volatile compounds in the juice of these species was determined, and principal component analysis was performed. Scores for the 1st and 2nd principal components are plotted as a scatter diagram. In Citrus Archicitrus, samples of Citrophorum, Cephacitrus and Aurantium formed individual groups, but others did not. In Citrus Metacitrus, samples of Acrumen were divided into two different groups. The composition of volatile components in citrus juice was consistent with each grouping of Tanaka’s system, in particular, in the case of dividing the Citrus genus into the two subgenera Archicitrus and Metacitrus.
The role of disulfide bonding in the structure of gels formed from soybean proteins was investigated. Heat-induced gels of 11S globulin (11S) and soybean protein isolate (SPI) were prepared using magnesium chloride as a coagulant, and the effects of 2-mercaptoethanol (2-ME), which prevents the formation of disulfide bonds, on the viscoelastic properties and microstructures of these gels were determined. The effects of 2-ME were quantified using dynamic viscoelastic measurement (DVM) and confocal laser scanning microscopy (CLSM). DVM indicated that 11S gels showed higher storage modulus (G’) and lower mechanical loss tangent (tan δ) than SPI gels. CLSM was used to examine microstructures of 11S and SPI gels, and to determine their fractal dimension and the average density of network structures. The 11S gels showed lower fractal dimension and denser gel networks than SPI gels. These characteristic viscoelastic properties and microstructures of the 11S gel were lost with increasing 2-ME concentration, suggesting that the characteristic properties of 11S gels are due to disulfide bonding.
Specific detection and enumeration of Salmonella enterica in food using conventional culture-based methods (CCBM) are time consuming and labor intensive. This study was conducted to develop a rapid S. enterica detection and enumeration method by combining fluorescence in situ hybridization (FISH) with micro-colony formation culture (FISHFC). Specificity tests of the SAL343 probe for S. enterica detection revealed that SAL343-associated fluorescent micro-colonies were observed specifically for S. enterica, but not for any other organisms. This finding suggests that SAL343 is highly specific for detecting S. enterica using FISHFC. For validation, FISHFC with SAL343 was compared to CCBM, with multiple selective agar, using spiked food samples; no significant differences in enumeration were found between FISHFC and CCBM (p > 0.05). The FISHFC method allowed enumeration of S. enterica within 10 h while CCBM allowed enumeration within 5 days. Therefore, the FISHFC method has potential application for more rapid and specific enumeration of S. enterica in food samples compared to other available methods.
Oxygen radical absorbance capacity (ORAC) value and polyphenol contents of extracts from 71 crops cultivated in Japan were determined. Hydrophilic ORAC values (H-ORAC) ranged from 194 − 29,830 μmol TE/100 g fresh weight (FW), whereas lipophilic ORAC values (L-ORAC) ranged from 6 − 2,076 μmol TE/100 g FW. High total ORAC value was indicated in the following vegetables and fruits: mulukhiya (Corchorus olitorius), perilla (Perilla frutescens), water spinach (Ipomoea aquatica), edible burdock (Arctium lappa), blueberries (Vaccinium corymbosum) and hardy kiwifruit (Actinidia arguta) (6,562 − 31,802 μmol TE/100 g FW). These extracts showed a strong positive correlation between ORAC value and polyphenol content (r = 0.98). In addition, to gain a better understanding of ORAC variability in Japanese crops, we also discussed the influence of environmental factors on the ORAC value of stem mustard (Brassica juncea) “Umino” grown in three different regions. Regional variations of ORAC in stem mustard likely result from different levels of ultraviolet radiation and fertilizer application regimens specific to those regions.
Amylase isozymes from non-glutinous japonica and indica rice types showed various band patterns, strengths and intensities based on zymography. Major bands were presumed to be α- and β-amylase according to their molecular weights; other amylases, 270 and 200 kDa in size, were also detected. Three debranching enzymes (DBEs) were detected from the dye pattern as well. Amylase activities were observed at pH 7.0 during rice cooking. However, the α-amylase activity at pH 7.0 was 50% lower than that at pH 5.0; DBE, β-amylase, and α-glucosidase values were similarly reduced by 25%, 90% and 99%, respectively. α-Amylase activity and DBE activities correlated positively with both the amount of malto-oligomer leached during rice cooking and the adhesiveness of cooked rice. Thus, it is considered that the activity of amylase isozymes affects the palatability of cooked rice. Therefore, enzymes from rice endosperm may represent a new and highly useful biomarker for evaluating the palatability of cooked rice.
Yeast strain 39-A was isolated as a lipase producer from the digestive juice of Nepenthes ventricosa. The yeast was identified as Cryptococcus flavescens by morphological tests and comparative 26S rDNA-D1/D2 and ITS-5.8S rDNA gene sequence analysis. The lipase from strain 39-A was purified from a culture filtrate by (NH4)2SO4 precipitation, and by chromatography with CM-Toyopearl 650M, Butyl-Toyopearl 650M, and Toyopearl HW-55. The purified enzyme appeared as a single band with 34 kDa on SDS-PAGE. The optimum temperature and pH were approximately 30°C and 7.0, respectively. The fatty acid specificity in milk triglyceride was similar to that of Lipase PGET, a pregastric esterase with short-chain fatty acid specificity in triglycerides. Lipase addition during the mozzarella cheese-making process produced a favorable cheese flavor. These results show that the lipase produced by C. flavescens 39-A has the potential to replace pregastric esterase in the dairy industry.
The use of hydrocolloids in different foods systems has become more commonly applied to improve the texture and quality of baked products. Nevertheless, the effects of these compounds on partially baked frozen chapatti have not been studied. The objective of the present study was to improve the storage stability, quality and shelf life of partially baked chapatti by adding various hydrocolloids, hydroxyl propyl methylcellulose (HPMC), carboxy methylcellulose (CMC) and guar gum, followed by frozen storage for 28 days. Partially baked and fully baked chapattis after frozen storage were analyzed for chemical and sensory attributes at 7-day intervals. Rheological studies showed an increase in water absorption, dough development time and dough stability after the addition of hydrocolloids. In partially baked chapatti with hydrocolloids after frozen storage, an increase in moisture retention and water soluble starch was observed. Sensory characteristics were also improved by combining both techniques. Among the hydrocolloids, HPMC exhibited the best results, followed by CMC and guar gum. These hydrocolloids and partial baking with frozen storage helped to improve the quality, and extend the shelf life of partially baked chapatti.
In this study, the effects of storage temperature, O2 permeability of packaging materials and variety on phenolic content and free radical-scavenging activity of vacuum-packaged walnut kernels were studied over a 12 months storage period. Methyl gallate (23.70 − 93.75 mg/kg), ellagic acid (137.95 − 569.22 mg/kg), and an ellagic acid pentoside (270.59 − 637.17 mg ellagic acid equivalent/kg) were identified in walnut varieties. While a slight decrease in the amount of ellagic acid was observed during 12 months storage, decreases in the amount of ellagic acid pentoside, total phenolic content and free radical-scavenging activity were severe. The present study concluded that it is possible to protect the phenolic content and antiradical activity of walnut kernels by packaging in Polyamide/Polyethylene laminate pouches having an oxygen permeability lower than 63.40 ± 0.40 (mL/m2/24h at 23°C) under vacuum at 20°C up to twelve months.
Oleanolic acid (OA) and ursolic acid (UA) are natural triterpenoids that have preventive properties such as anti-tumor and anti-hepatitis activities. These triterpenes are known to exist in several medicinal plants and fruit skins. Dried fruits are usually eaten without removing the skin; thus, they may be good resources for oral intake of OA and UA. HPLC analysis of OA and UA contents in a variety of dried fruits showed that raisins contained higher levels of OA than the other fruits investigated, with green raisins containing the highest levels (79.0 mg/100 g). While raisins were found to contain only OA, dried cranberries, blueberries and cherries were shown to contain both OA and UA. The highest level of UA (65.9 mg/100 g) was detected in cranberries, which also exhibited relatively high OA levels (17.8 mg/100 g). Thus, raisins and dried cranberries can be used as rich sources of OA and UA.
The role of superoxide anion radical (O2−) in the improvement of bread dough by L-ascorbic acid (AsA) was examined. Since AsA makes detection of thiyl radicals (S•) difficult, riboflavin was used as a photoinduced O2− producing agent in substitution of the classical improvement molecule. The preparation of soluble glutenin was successfully achieved by means of deamidation using protein glutaminase. Electron spin resonance (ESR) spectroscopy coupled with spin trapping revealed the presence of photoinduced S• in a solution containing riboflavin and soluble glutenin. Unlike catalase, addition of superoxide dismutase suppressed the production of S• in the soluble glutenin. These results suggest that the O2− produced during the oxidation of AsA in dough is responsible for the generation of S• in gluten proteins, thereby increasing the production of inter-protein disulfide bonds and resulting in an improved bread structure.
To investigate the effect of catechins on Cu dynamics in mice, the body hair of mice administered with or without green tea extract was subjected to neutron activation analysis at a research reactor. Neutron activation analysis revealed that green tea extract might have the ability to promote excretion of Cu from the body to the hair.
We investigated 29 Lactobacillus strains isolated from Japanese traditional fermented food products made from rice grain or bran in order to select strains that potently suppress IgE production. First, in vitro screening was carried out to select candidates with strong induction activity for IL-12 and INF-γ production and suppression activity for IL-4 production in mouse splenocytes. Based on the screening data, 3 strains were selected and orally administrated to ovalbumin (OVA)-immunized mice. Among these 3 strains, Lactobacillus paracasei K71 (L. paracasei K71) isolated from sakekasu (sake lees) was shown to be the most potent for decreasing total and OVA-specific IgE levels in serum. L. paracasei K71 may down-regulate IgE production via the induction of Th1 responses and suppression of Th2 responses in vivo.
Wasabi (Wasabia japonica) is a traditional condiment used in Japanese dishes. The wasabi rhizome shows potent amylolytic activity. The amylase activities of 12 Brassicaceae vegetables, including wasabi and three non-Brassicaceae root vegetables, were determined and compared. Among the 15 vegetables, wasabi showed the highest amylase activity (203 U g-1 fresh weight). The second and third highest activities were found in horseradish (14 U g-1 fresh weight) and sweet potato (8.6 U g-1 fresh weight), respectively. The 12 other vegetables exhibited activities less than 3 U g-1 fresh weight. Immunoblot analyses using an anti-radish (Raphanus sativus) β-amylase antibody indicated that wasabi contained an abundance of the antigen. Tissue printing indicated that the β-amylase antigen is generally distributed throughout the wasabi rhizome. These results suggest that wasabi contains a large amount of β-amylase, and therefore shows strong amylolytic activity.