This study was conducted to characterize the bacteriostatic activities of aqueous garlic bulb- (GBE), ethanolic lemon peel- (ELPE), and ethanolic orange peel (EOPE) extracts against Escherichia coli K-12, E. coli O157:H7, Salmonella enterica serovars, Listeria monocytogenes, and Staphylococcus aureus in a tomato-based meat sauce. The maximum permissible supplementation (MPS) levels of GBE, ELPE, and EOPE in the meat sauce formulation determined through sensory evaluations were 6.0%, 3.0%, and 3.0%, respectively. However, the MPS values of ELPE and EOPE did not inhibit any of the test organisms in the subsequent antibacterial assays, with minimum inhibitory concentration (MIC) values of 6.0 – 9.0% (ELPE) and 7.5 – 10.0% (EOPE). On the other hand, GBE had an MIC values range of 1.0 – 2.5%. Thus, the study also determined the minimum inhibitory combination (MICo) values of GBE+ELPE and GBE+EOPE. Results showed that co-supplementations of the test extracts resulted in MICo values of 3.0% GBE +3.0% ELPE and 3.0% GBE +3.0% EOPE. Supplementation of the meat sauce with these MICo resulted in products with similar consumer acceptability scores as the non-supplemented control. Supplementation of inoculated meat sauce with the MICo of the test extracts exhibited bacteriostatic effect on selected pathogens in time-temperature abused (31°C, 8 h.) meat sauce.
This study investigated the influence of mixing and fermentation times on the chemical and physical properties of white pan bread, a typical bread consumed in Japan. Sixteen bread samples were made by combining four dough mixing stages and four dough fermentation times, and were analyzed for compression force, acids, sugars, amino acids, volatile chemicals, and overall preference in a sensory evaluation. Acids, sugars, and amino acids were analyzed using HPLC, while volatile flavor compounds were analyzed with GC/MS. The effects of mixing and fermentation times on these parameters were analyzed using analysis of variance (ANOVA). Fermentation time was positively correlated with the majority of volatile chemicals and acids, and negatively correlated with amino acids. Compression force and sugars, such as galactose and maltose, were affected by both mixing and fermentation times. Overall preference was highest in the breads mixed to the over-mixing stage and fermented for 60 min. The results of this paper are expected to be of importance in controlling the flavor, taste, and texture of white pan bread.
This study evaluates the effects of a microwave and steam cooking combination on the sugar composition, phytochemical compounds (total phenolics, total flavonoids, total anthocyanins and phenolic acids and anthocyanin compositions) and antioxidant capacity of purple sweet potatoes (PSPs). The combination of microwave and steam cooking could significantly decrease the cooking time. The results show an obvious increase in the quantity of total phenolics, flavonoids, and anthocyanins in PSPs after cooking. The microwave and steam cooking combination induced the greatest increase for the total flavonoids and total phenolics, with values of 22.2% and 26%, respectively. Among the phenolic acids in the PSP extract, chlorogenic acid was the major constituent, and phenolic acid concentrations increased after cooking, except for caffeic acid. An HPLC-MS analysis of anthocyanin showed that the cyanidin-3-(6″-caffeoyl-6″′-feruloylsophoroside) -5-glucoside and peonidin-3-(6″-caffeoyl-6″′-feruloylsophoroside)-5-glucoside contents in PSPs cooked with steaming for 10 min followed by microwaving for 3 min (S10 − M3) were highest among the cyanidin and peonidin compounds. The PSPs exhibited a greater antioxidant capacity after cooking, and the S10 − M3 cooking method produced the greatest antioxidant capacity. Therefore, an appropriate combination of microwave and steam cooking can better retain phytochemical compounds in PSPs and increase antioxidant capacity compared with only steaming or microwaving.
In order to improve the processing properties of texturized wheat gluten (TWG), we studied the effect of calcium stearyl lactylate (CSL) (0 – 0.12%, w/w) on the physicochemical properties and structure of TWG using a twin screw extruder. Results showed that the hardness, adhesiveness, and chewiness of TWG significantly increased by 161.55%, 225.06% and 138.54%, respectively, with addition of 0.08% CSL during twin-screw extrusion processing. Moreover, Raman spectroscopy indicated that CSL encouraged new disulfide bond formation during extrusion treatment. Infrared spectroscopy and reducing electrophoresis demonstrated that CSL inhibited the Maillard reaction. Increasing the amount of CSL resulted in shifts from α-helix and β-turn structures into β-sheet and random coil structures, as evidenced by secondary structure analyses. Overall, features of TWG were modificated by CSL which made TWG a valuable material can be used for the development of fibrous meat alternatives, thus widening the application of wheat gluten products for meeting consumer requirements.
The quality and yield of Luzhou-flavor liquor is directly determined by the quality of pit mud from the Luzhou-flavor liquor distillery. The aged pit mud produces the good quality liquor while new pit mud dose not. The aim of this study was to investigate the prokaryotic community diversity between new and aged pit mud by high-throughput sequencing technique and the real-time quantitative PCR (qPCR) assay. Results indicated that diversities of prokaryotic community in new pit muds were higher than those in aged pit muds. The abundances of the phylum Bacteroidetes in aged pit muds were significantly (P < 0.05) higher than those in new pit muds, while the abundances of the genus Lactobacillus and Bacillus changed in the opposite trend. Additionally, the quantity of Clostridium Kluyveri in aged pit mud was higher than that in new pit mud. Bacteroidetes, Lactobacillus, Bacillus and C. kluyveri may be the potential indicator-like microbe to distinguish new and aged pit mud fast, conveniently and reliably by qPCR. Results presented in this study provide specific understanding of the differences in prokaryotic community between the new and aged pit muds, and have laid initial foundation for identifying aged pit mud and for advancing pit mud aged.
In this study, the storage characteristics of high-amylose rice gel and emulsified rice gel, two intermediate food materials, were investigated. High-amylose rice was gelatinized and sheared at a high speed to create rice gel. Cooking oil was added to the rice gel and the mixture was mixed at a high speed to create emulsified rice gel. The ratio of rice to liquid, which is water in the rice gel and water and oil in the emulsified rice gel, was set to 1:1.5 or 1:4. The emulsified rice gel and rice gel were stored under refrigerated (4°C) and freezing (−20°C) conditions. Temporal changes in the physical properties were compared by measuring the dynamic viscoelasticity after 1, 7, and 14 days of storage. The results show that the temporal changes in E* and tanδ for the emulsified rice gel were smaller than those for the rice gel. The results suggest that the emulsification process can effectively suppress changes in the physical properties of rice gel over time.
Pullman type white breads with or without Yudane dough at 10 and 20% (w/w, flour base) were made by the no first fermentation method. Yudane dough was prepared by mixing boiling water and flour at a 1:1 ratio. The breads were stored at various temperature conditions and then subjected to analyses of bread hardening (temporal changes in hardness), hardening rate constant of bread (HRC), and simulation of hardening behavior using a hardening model. The results were as follows: The hardening of all breads slowed with the increase in storage temperature. The hardening of breads made with Yudane dough (Yudane breads) was slower than that without Yudane dough (Control) at any storage temperature. The HRC of all breads sharply decreased with the increase in storage temperature. By using the hardening model, the hardening behavior of all breads stored at various temperature conditions was simulated with considerable accuracy.
The surface roughness of spaghetti is an important factor influencing noodle quality during and after cooking. In this study, we describe a novel, rapid, and low-cost method, based on the principal that an object with a rougher surface refracts more light, to measure the surface roughness of spaghetti using images acquired with a common digital camera. This method helps determine the surface roughness using gray-level frequency distributions from transmission images and facilitates the measurement of surface geometry to the same accuracy as that of traditional, high-performance laser-scanning microscopy techniques. Furthermore, this method enables rapid measurement of the entire surface geometry of the spaghetti, including the steeply sloped and shaded regions, which are difficult to measure by the conventional laser method, owing to lower reflectance or shielding of the laser beam.
Dimethyl trisulfide (DMTS) develops in wine during storage, creating an unpleasant aroma. However, the mechanisms of DMTS formation during the wine-making process are poorly understood. We attempted to identify the factors that affect DMTS development during storage. We found that the death of yeast cells, followed by the leakage of their cell contents into the must, enhanced DMTS formation, but this effect varied between grape cultivars. Oxidation of the must and insufficient clarification of the grape juice can also lead to DMTS development during storage. However, DMTS-P1 and methanethiol, precursors of DMTS in other beverages, contributed little to DMTS formation in wine. When synthetic grape must was fermented instead of grape juice, less DMTS developed, despite most yeast cells having died. These findings indicate that unknown compounds contained in grape juice are involved in DMTS formation and that the key compounds involved in DMTS formation in wine originate from grapes.
Fewer studies on the effects of heat treatment on casein under acidic conditions have been reported compared with those under neutral conditions. This study aims to clarify the effect of heat treatment under acidic conditions on the properties and functions of milk proteins. The turbidity of reconstituted skimmed milk increased with increasing temperature (70 – 90°C) and pH (3.40 – 3.55). Suspensions of heated samples were stable and did not sediment at low-speed centrifugation. Mean particle diameters of heat-induced particles were 200 – 680 nm. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis and ion-exchange high-performance liquid chromatography revealed that heat-induced colloidal particles comprised αS1-casein and β-casein. αS2-Casein did not participate in aggregate formation. The proportion of αS1-casein and β-casein did not change regardless of temperature, whereas the proportion of β-casein was dependent upon pH. The results showed that heat-sensitivity of casein constituents at pH 3.30 – 3.55 is markedly different from that under neutral conditions, and some caseins aggregate into stable colloidal particles upon heating.
Gelatin is extracted from animal tissues using heat usually with low yields, but pepsin may increase high quality gelatin yield per unit of tissue. Gelatin from bovine lungs was extracted using heat and pepsin and the resulting gelatins were characterized. Pepsin increased gelatin yield by about 9-fold that of heat extraction alone. All bovine lung gelatin contained protein as the major proximate component, with little ash and non-detectable fat. Bovine lung gelatin had pH, moisture and protein comparable to or less than that of commercial bovine gelatin and decreased ash. Transmittance of bovine lung gelatin was substantially reduced compared to that of commercial bovine gelatin but had increased water and fat-binding capacity, and comparable or increased gelling and melting temperature. Gel strengths of bovine lung gelatin were comparable to or lower than and foam stability and emulsifying activity were lower than commercial bovine gelatin. Increased imino acid (proline and hydroxyproline) content was associated with increased gelling and melting temperatures and was comparable to commercial bovine gelatin. Heat-extracted bovine lung gelatin contained predominantly collagen γ– chains, β– chains and α– chains (α1(I) and α2(I)), with some low molecular weight peptides, while the pepsin-extracted lung gelatins were characterized by comparatively decreased β– and α– chains and increased low molecular weight peptides. The gel strength of heat-extracted bovine lung gelatin was higher than that of pepsin-extracted gelatins, indicating that additional yield was associated with reduced gelatin quality. Bovine lung is a potential source of gelatin for application in diversified industrial fields and use of pepsin is a viable method for extracting additional gelatin after heat extraction of high quality (increased gel strength) gelatin from bovine lung.
To quantitatively evaluate the production of staphylococcal enterotoxin A (SEA) in cooked rice, we inoculated 11 strains of SEA-producing Staphylococcus aureus into cooked rice, incubated the samples at 15 – 37°C, and quantified SEA. The maximal concentrations of SEA were 0.0 (not detected)-4.0 ng/g at an incubation temperature of 15°C, 0.4 – 8.4 ng/g at 20°C, and 2.3 – 53.8 ng/g at 37°C with an inoculum size of 106 CFU/g. There were few correlations among the maximal concentrations of SEA at incubation temperatures of 15, 20, and 37°C or between the maximal concentrations of SEA produced in a liquid medium and in cooked rice. Although the predicted amounts of SEA produced in a rice ball under conditions of 16 h of incubation at 20°C or 4 h at 37°C appeared to reach levels capable of causing staphylococcal food poisoning, S. aureus growth under these conditions was not organoleptically detected.
Turmeric (Curcuma longa) is used as a food ingredient, coloring agent, and traditional medicine. While various medicinal properties of turmeric have long been known, scientific reports on its prevention and alleviation of alcohol hangover are scarce. In this study, we employed an assay system for the preventive effect of a turmeric extract against ethanol-induced hepatocyte injury, a presumed cause of alcohol hangover, and screened for its active compounds. The preventive effect of the turmeric extract and its fractions was assessed using primary hepatocytes isolated from Sprague-Dawley rats. The turmeric extract containing 6 µM curcuminoids showed stronger cytoprotective activity than the purified curcuminoids at 6 µM. The structures of additional active compounds were determined as ar-turmerone and bisacurone by NMR and mass spectrometry. Among curcumin, ar-turmerone, and bisacurone, bisacurone appeared to be most effective and showed preventive effects at concentrations as low as 1 µM.
During research on the Maillard reaction between xylose and lysine (Lys), we detected a major peak showing an absorbance maximum at about 280 nm by diode-array-detection (DAD)-HPLC. In this study, the peak was isolated and identified as 4-hydroxy-5-methyl-3(2H)-furanone (HMFO). This compound accounted for 60 – 80% of the total area of HPLC peaks (280 nm), and about 20 mg/100 mL of HMFO was produced from a solution containing 200 mg/100 mL of xylose. HMFO was produced not only from xylose, but also from arabinose and ribose, and ribose was the best precursor. When HMFO was heated in a buffer solution with or without Lys, it was decomposed or polymerized, and colored and colorless polymers appeared. Diacetyl and methylglyoxal were the major decomposed dicarbonyl compounds from HMFO; these dicarbonyl compounds are considered to be the major precursors for polymers formed from HMFO.
Baking with bread dough containing fresh rice flour/fresh wheat gluten flour was found to produce good quality rice bread. However, bread dough containing stored rice flour displayed inferior bread-making properties. The stored rice flour exhibited hydrophobicity, which is known to be closely associated with inferior bread-making properties. To reduce the hydrophobicity of the stored rice flour, various amounts of sucrose fatty acid ester (SFAE) were added during an oil-binding test. When 0.5 mL of 2.7% SFAE solution was added to the stored rice flour in the oil-binding test, the hydrophobicity of the rice flour disappeared. Thus, the addition of SFAE to stored rice flour improved its bread-making properties. Dry-heated rice flour demonstrated the same poor rice bread-making properties as stored rice flour. The addition of SFAE to dry-heated rice flour in the oil-binding test reduced the hydrophobicity of the flour.
This study was to examine the effects of certain methodologic choices for testing glycemic index (GI), incremental area under curve (IAUC), and blood glucose responses in 12 healthy adults, who were fed white rice, rice porridge, and overnight rice. Blood samples were collected from venous plasma (VP), capillary plasma (CP), and capillary blood (CB). The results showed the mean GI value (VP; 87 ± 2.5, CP; 85 ± 2.5, and CB; 84 ± 2.6); the mean IAUC (CB; 5006 ± 292, CP; 4844 ± 287, VP; 3784 ± 221 ); the mean postprandial glucose response (CB; 118.2 ± 3.3, CP; 115.2 ± 3.2, VP; 90.7 ± 2.4); Significant correlation was observed between three sampling methods (p < 0.01). In conclusion, the VP sampling approach had a lower degree of dispersion and a higher stability that is a more effective methods to determine GI, IAUC and blood glucose responses. and rice porridge produced the highest GI, followed by white rice and overnight rice.
Tight junction (TJ) integrity is one of the key factors governing intestinal health. Isomaltodextrin (IMD), a highly branched α-glucan, has been characterized as a new type of soluble dietary fiber. Here, we evaluated the efficacy of IMD to improve the barrier function of TJs. Transepithelial electrical resistance (TER) and Lucifer Yellow (LY) leakage were measured after treating Caco-2 cells in vitro with IMD. A mouse model of dextran sulfate sodium (DSS)-induced colitis was used for the in vivo studies. IMD treatment in vitro maintained TER at higher levels and reduced LY leakage significantly. IMD preloading of mice reduced the signs of DSS-induced colitis compared with the Water group. Immunohistochemical and western blotting analyses of the colon in the IMD group revealed enhanced claudin-3 and ZO-1 expression, indicating the role of IMD-induced TJ strengthening in the alleviation of colitis. The ingestion of IMD has beneficial effects on colon health by improving TJ integrity.
Nonalcoholic steatohepatitis (NASH) is characterized by excess lipid accumulation and inflammation in hepatocytes. In this study, to provide insight into the preventive effects of d-allose, a rare sugar, on the onset of NASH, we designed animal experiments using male STAM mice treated with streptozotocin and fed a high-fat diet (HFD). Experiments were initiated when the mice reached 5 weeks of age and lasted 3 weeks. After the 3-week protocol, mice fed the HFD containing d-allose exhibited significantly decreased serum alanine aminotransferase levels, hepatic lipid accumulation and inflammation, and improved nonalcoholic fatty liver disease activity score compared to mice fed HFD without d-allose (p < 0.05). Further, hepatic mRNA expression of sterol regulatory element binding protein-1 (Srebp-1) and monocyte chemotactic protein-1 (Mcp-1) was lower in mice fed d-allose. These results suggested that d-allose prevented NASH by blocking hepatic lipid accumulation and progressive inflammation.
The application of proanthocyanidins (PCs) in food industry is limited because of its instability and vulnerability against oxidative damage. In this work, by taking advantage of the reversible assembly characteristic of ferritin, apo-red bean ferritin (apoRBF)-PCs composites (FPs) were designed, and results showed a ratio of 1/10 of PCs (PCs/apoRBF, w/w) were encapsulated into a ferritin cage, and the encapsulation ratio was 23.8%. The FPs exhibited a homogeneous form, and maintained a spherical morphology. Further more, the thermal and light stability of PCs in FPs was significantly increased compared to free PCs (p < 0.05). The in vitro digestion indicated that apoRBF could prolong the release of PCs in simulated gastrointestinal tract. Additionally, the antioxidant activity of FPs was partly retained (56.6%) as compared to free PCs. This work offers a novel method to encapsulate and stabilize polyphenols and might be favorable for the application of ferritin in food industry.
We attempted to reduce the digestibility of potato starch by adding fatty acids (palmitic or linoleic acid) and treating with heat in order to develop a starch product with high consumer acceptability. The starch digestion rate was measured by enzymatically hydrolyzing starch samples using porcine pancreas α-amylase (EC 188.8.131.52) and amyloglucosidase (EC 184.108.40.206), and measuring the amount of glucose released after 90 min. In addition, we evaluated the starch digestion rate by calculating the in vitro glycemic index (EGI) using the method of Goni et al. (1997). The greatest EGI reduction (approximately 60% reduction compared to non-treated samples) was observed in potato starch samples adjusted to 20% moisture content and to which at least 3% fatty acid had been added. In this study, we were able to create a resistant potato starch by using simple food processing techniques of fatty acid addition and heat treatment.
Wasabi is a plant of Japanese origin. It belongs to the Brassicaceae family and produces various isothiocyanates (ITCs). Because 6-methylsulfinylhexyl isothiocyanate (6-MSITC) is particularly stable among wasabi ITCs, it has potential as a functional compound. To clarify the antioxidative activity of 6-MSITC, we investigated its inhibitory effect on superoxide anion (O2•−) generation from phorbol 12-myristate 13-acetate (PMA)-stimulated differentiated HL-60 human promyelocytic leukemia cells. Our results showed that 6-MSITC inhibited O2•− generation in these cells (IC50 value: 28.9 µM). 6-MSITC at 0.8, 4, and 20 µM significantly inhibited the consumption of exogenously added NADH compared with the control. On the other hand, < 263 µM 6-MSITC did not scavenge O2•− in cell-free experiments. Therefore, we suggest that 6-MSITC inhibited O2•− generation by decreasing an enzymatic reaction with NADPH oxidase. Thus, 6-MSITC may be useful as a functional compound.
1-Deoxynojirimycin (DNJ) is an effective sugar analogue that suppresses the elevation of postprandial blood glucose. Therefore, food products containing DNJ are expected to be promising functional foods in preventing the onset of diabetes. To examine the absorption kinetics of DNJ, we prepared 15N-labeled DNJ from the culture medium of a Bacillus amyloliquefaciens DSM7 strain. In the process, we found that lactose markedly increased the production of DNJ at a carbon/nitrogen ratio of 6.25:1, reaching 1140 mg/L with 5 days of cultivation. Comparisons between lactose and glucose on cell growth and DNJ production suggested that lactose made the DSM7 strain grow more slowly and maintained DNJ production in the long term. These findings may be useful for efficient microbial DNJ production or in the development of DNJ-containing fermented food products.
There are few reports on the combined effect of epigallocatechin gallate (EGCG) and quercetin (QU) on the arteriosclerosis index (AI) in mice fed a normal diet. The effects of diets with high flavonoid contents on body and liver weights, and AI were investigated in C57BL/6 J mice. Five-week-old C57BL/6 J mice were fed diets containing EGCG (0.01 – 1.0%), QU (0.01 – 1.0%), or EGCG + QU (0.03% each) for 4 weeks. After breeding, body and liver weights were measured. Blood samples were collected by cardiac puncture and total, HDL, and LDL cholesterol levels were measured. The flavonoid containing diets appeared to have slight effects on both body and liver weights. Cholesterol levels changed slightly after breeding of mice fed any of the three diets. The results indicated that these flavonoids have very slight effects on weight gain and liver weight. AI was significantly reduced in breeding mice fed the combination (EGCG + QU) diet. These results suggest that the combination of EGCG and QU is beneficial for the maintenance of cardiovascular health.