The intestinal epithelial cells serve as a frontline to the intestinal tract. These cells serve various important functions and harbor the detoxification enzymes that function as an essential intestinal biological barrier system. The detoxification enzymes catalyze oxidation (phase I), conjugation (phase II), and excretion (phase III) reactions in three phases of metabolism to eliminate toxic compounds from the body. These detoxification enzymes are regulated by transcription factors, particularly nuclear receptors and drug receptors, such as the pregnane X receptor (PXR) and the aryl hydrocarbon receptor (AhR). On the other hand, because intestinal epithelial cells are routinely exposed to food, the activity of detoxification enzymes is thought to be regulated by food components. In this review, we highlight research from our group and others that have focused on understanding the role of food components in regulating the expression of detoxification enzymes via transcription factors in intestinal epithelial cells.
Pulsed Electric Field processing is a non-thermal alternative to sucrose extraction from sugar beet. The aim of the study was to investigate the impact of pulsed electric field (PEF) treatment on the viscoelastic properties of sugar beet tissue. The electrical conductivity disintegration index was used for characterization of the PEF-induced damage of sugar beet tissue. Cell membrane disintegration increased with increasing field strength and pulse number. Stress-relaxation tests were also performed. The changes in viscoelastic properties were quantified as a result of applied field strength and pulse number and were correlated with cell disintegration index. The generalized Maxwell model was used to fit the measured stress–relaxation data. The rheological constants, elastic module (MPa), equilibrium elastic module (MPa) and relaxation time (s) were decreased significantly with increase of cell disintegration index. Scanning electron microscope images of the intact and PEF- treated samples showed increased deformation of cells and larger intercellular spaces for the PEF-treated samples.
The chemical compositions, fatty acids, total flavonoids content (TFC), total polyphenols content (TPC), and minerals of walnuts were investigated after freeze drying (−55 °C) and heat drying (60 °C, 105 °C, 140 °C) process. The results showed that the contents of protein, soluble sugar, minerals (except for Mn), and carbohydrate were increased with the rise of temperature from −55 °C to 105 °C. Linoleic acid and oleic acid could be detected as the main fatty acids, with the highest contents were also observed at 105 °C (309.0 mg/g and 79.6 mg/g). However, the TFC and TPC were notably increased by 36.9% and 33.9% in kernel when the temperature was increased from −55 °C to 140 °C. In general, the freeze drying and heating drying had an inhibition effect and irritation effect on the nutritional qualities of walnuts, respectively. Therefore, heating treatment could significantly improve the nutritional qualities of walnut, and the recommended temperature for walnut drying was 105 °C.
Protein hydrolysates are used for various purposes such as hypoallergenic food, clinical applications, and functional food. However, hydrolysed peptides usually present intense bitter tastes. We previously created a new type of silica gel without chemical modification and found that this material highly adsorbed hydrophobic or positively charged peptides under neutral conditions. Bitter peptides possess bulky basic groups or hydrophobic groups, and we examined the applicability of these as a new bitterness removal carrier. As a result, we confirmed that bitter peptides were more selectively adsorbed compared to other commercial materials and the bitter taste was significantly reduced. These results indicate the utility of our material as a pretreatment carrier. Moreover, silica gel is approved as a food additive and we created this material by subjecting to heat treatment only; thus, it has high food safety and is applicable as a bitterness-masking material.
A novel method was developed to separate the tea polyphenols epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) by two-step chromatography. In the first-step, four different macroporous absorption resins were compared by dynamic desorption, of which only AB-8 resin resulted in enriched fractions for EGCG and ECG. Their purity was 53.69%, and 65.77%, with recovery rates of 88.05%, and 83.46%, respectively. For the second-step, The recovery rates of 85.36% and 86.09% for EGCG and ECG were obtained respectively by a novel stationary phase of β-CD bonded agar gel. The overall recovery efficiency of the complete procedure was 75.16% for EGCG and 71.85% for ECG, respectively, and the purity of the obtained preparations reached 97.63% for EGCG and 98.09% for ECG. The chromatographic behavior of β-cyclodextrin bonded agar gel was studied with elution by acetonitrile, which indicated that both hydrophilic and hydrophobic interactions between the polyphenols and the solid phase occurred.
Chlorogenic acid (CA) has strong oxidative resistance. The content of CA is high in Eucommia ulmoides leaves which are easily available and low cost. Therefore, in this work, using Eucommia ulmoides leaves enzymatic hydrolysate (EEH) as the main material, the fermentation conditions of Eucommia ulmoides leaves vinegar (EV) were studied to increase the antioxidant activity of the vinegar. Box-Behnken design indicated the following optimal fermentation conditions: EEH 48%, acetic acid bacteria solution 10%, ethanol addition 6%. Under above conditions, the acetic acid content and CA content of EV was 41.5±2.2 mg/mL and 1.1±0.17 mg/mL, respectively. EV exhibited the higher antioxidant activity, with IC50 values of 2.62 µg/ mL, 27.21 µg/mL and 1.72 mg/mL for DPPH, hydroxyl radical scavenging activity and reducing power, respectively. The addition of Eucommia ulmoides leaves increased the antioxidant activity of vinegar.
The “Koshitanrei” rice cultivar is grown and widely used for sake brewing in Niigata Prefecture; however, the starch characteristics of this cultivar have not yet been elucidated. Therefore, we investigated the influence of starch properties on the gelatinization properties and digestibility of this cultivar, which are very important in sake production. Starches of rice samples milled to 60% yield from “Koshitanrei,” “Yamadanishiki,” “Gohyakumangoku,” and “Koshiibuki” were subjected to iodine colorimetric scanning analyses and pasting properties were investigated using a rapid viscosity analyzer. The correlation between iodine absorption and digestibility was analyzed following steaming of the rice samples. The findings of our study showed that the maximum wavelength of the iodine absorption curve (λmax), which is derived from the chain length distribution of amylopectin, of Koshitanrei was the same as for Yamadanishiki, followed by Gohyakumangoku and Koshiibuki. Further, we found that λmax was significantly correlated with enzyme digestibility. The results of our study show that enzyme digestibility can be estimated by a simple evaluation method, that is, iodine absorption scanning analysis.
Manual pipette methods are conventionally used to determine the viscosity (η) of gelatin solutions. The purpose of this study is to demonstrate the accuracy and precision of viscosity measurements of gelatin solutions using a rotational rheometer. Seven gelatin samples with different molecular weights were tested. The 2 × standard deviations of the obtained η were within ± 2.4% of the mean values in triplicate measurements, suggesting the evident precision of the viscosity measurements. Accuracy was demonstrated by the triplicate measurements of the standard liquids for a viscometer. The sample volume required by the rheometer was only 0.6 mL, whereas gelatin solutions of approximately 100 mL are usually required for pipette methods. We propose viscosity measurement using a rheometer as an alternative method to the pipette ones.
In this study, we investigated the starch, pasting, thermo-physical, and iodine absorption spectrum properties of Chou 2418, a new amylopectin long-chain (ALC) rice cultivar developed by crossing a high amylose rice cultivar Koshinomenjiman and amylose extender mutant rice cultivar EM10. Chou 2418 exhibited high apparent amylose content, high pasting temperature, and low breakdown viscosity. The iodine absorption spectrum indicates that Chou 2418 contains long-chain glucans of amylopectin and also has high amylose content. Boiled rice grains of Chou 2418 contained more resistant starch (RS) than those of high amylose rice cultivars. The RS content of Chou 2418 rice grains increased following the retrogradation of starch granules, and the grains became hard and non-sticky. The RS content of Chou 2418 was 25 times higher than that of Koshihikari, the most popular rice cultivar. Taken together, these data suggest that Chou 2418 is a suitable raw material for bio-functional foods that help prevent diabetes.
The physical properties of dough (PPD), instantaneous elasticity, regularity coefficient of viscosity, and relaxation time (τ0), of various white bread doughs without yeast addition were measured by the creep method based on a Maxwell-2-element model (Maxwell model). It was assumed that PPD do not change during fermentation and thus the stress of various doughs in the proofing process could be obtained using Euler's method. Simulation results revealed that dough with large elastic characteristics, a large τ0, and fermented quickly had a high stress peak during the expansion process and that the final stress (σend) also had a high value compared to other doughs. Meanwhile, dough characterized by a small τ0 and slow fermentation showed the opposite tendency. Additionally, the calculated σend was significantly correlated with the gas retention of dough and specific loaf volume (SLV). These results demonstrated that SLV of various white bread doughs could be estimated using PPD and fermentation speed.
Bread substituted with mashed potato (MP) instead of wheat flour has been attracting attention because of added components, such as gelatinized starch (GS), dietary fibers (DFs), vitamins, and minerals, etc., that have a beneficial effect on the nutritional value, texture, flavor, and taste of the bread. On the other hand, excess amounts of GS and DFs in MP inhibits gluten network formation in dough and greatly deteriorates the bread making quality (BMQ). In this study, we investigated the optimal addition of two types of bakery enzymes, α-amylase (AM) and hemicellulase (HC), to improve the BMQ of MP-added dough. Optimal amounts of added enzymes were determined using the response surface methodology (RSM) and optimization technique (OT). As the results, BMQ, such as specific loaf volume (SLV), gas retention of dough, and bread staling, of MP dough and bread with optimal concentrations of AM and HC were remarkably improved compared to those without enzymes. These results showed that RSM and OT were effective methods to reasonably and easily derive the optimal concentrations of multiple enzymes, resulting in a good quality MP-supplemented bread with high SLV, desirable texture, flavor, and taste, but not crust color.
This work studied the possible use of Thymbra capitata essential oil in the preservation of pomegranate juice qualities. We monitored the effect of the oil on the physicochemical and microbiological qualities of the juice during 245 days of storage at 5 and 20 °C. Treated juices showed slight decrease of pH, total sugars and phenolic contents after 245 days of storage. Additionally, the essential oil had a significant effect on the juice microbiological quality and caused a decrease of bacterial count after the first day of storage. In conclusion, Thymbra capitata essential oil may be used as natural preservative in pomegranate juice to preserve its physicochemical and microbiological qualities in a long-term storage.
Five hundred and sixteen food samples retailed in Japan were examined for viable bacterial counts (VBC), coliforms, and Cronobacter spp. Cronobacter spp. was detected in 12.4% (64/516) of the total food samples, comprising 15.4% (35/228) in agricultural products, 14.7% (28/190) in livestock products, 1.5% (1/65) in marine products, and 0% in infant foods (0/33). Cut and packed vegetables for cooking, flours, and beef offal showed the high prevalence of Cronobacter spp., whereas raw milk, marine products, and infant foods showed the lower prevalence. High correlations were observed between the levels of VBC and the prevalence of Cronobacter spp., and the levels of coliform and the prevalence of Cronobacter spp. in some types of food sample. Cronobacter spp. was seen in bovine feces (37.5%, 3/8), soil (16.7%, 4/24) and composts (10.0%, 1/10). These results suggested that the bovine feces might be one of the potent natural habitats of Cronobacter spp.
This study investigated the effect of epigallocatechin gallate (EGCg) on Staphylococcus aureus to determine its mechanism of antibacterial action. Adsorption of EGCg on the cell envelope of S. aureus after EGCg treatment was demonstrated using a FITC-labeled antibody specific to EGCg. After EGCg treatment of S. aureus for 4 h, abnormalities in septum formation and cell segregation were observed at concentrations greater than 250 mg/L, and debris presumed to arise from cell destruction or leakage of cytoplasmic materials was observed around the cells at 500 mg/L. Two-dimensional electrophoresis of proteins prepared from EGCg-treated S. aureus cells revealed the presence of 18 protein spots that disappeared or showed markedly decreased intensity compared to those from control cells. These proteins included DnaK, elongation factor G, DNA-directed RNA polymerase, l-lactate dehydrogenase, pyruvate dehydrogenase, and acetate kinase. Furthermore, S. aureus showed decreased glucose uptake after EGCg treatment. These results suggest that EGCg inhibits the functions of cell-envelope proteins, and it causes cellular damage and disruption of the cells in S. aureus.
The aim of this study was to investigate the composition and contents of anthocyanins and proanthocyanidins, and the antioxidant capacity of black and red cowpeas grown in Japan, with comparison to grain legumes (black kidney beans, black soybeans, and azuki beans) commonly consumed in Japan. This study revealed that black cowpeas contained seven anthocyanins, the 3–O–galactosides and 3–O–glucosides of cyanidin and delphinidin, and the 3–O–glucosides of malvidin, peonidin, and petunidin, at higher levels than other grain legumes. In addition, black and red cowpeas were rich in proanthocyanidin oligomers (monomers to hexamers) when compared with other grain legumes. Among these, black and red cowpeas showed potent hydrophilic oxygen radical absorbance capacity (H–ORAC), reaching 540.6 and 367.5 µmol–Trolox equivalents/g–dry matter, respectively. The contributions of anthocyanins and proanthocyanidin oligomers to H–ORAC values were 45.8% and 17.5% in black and red cowpeas, respectively.
Oligomeric polyphenol-enriched specified kiwifruit extract (SKE) is reported to inhibit pancreatic lipase activity in vitro. Therefore, in this work, we investigated the effects of SKE on body weight, visceral fat, and lipid metabolism in mice fed a high-fat diet for 6 weeks. Body weight gain was significantly and dose-dependently suppressed in the groups fed a high-fat diet containing SKE (HF + SKE groups) compared to the high-fat diet control group (HF group). Moreover, Dose-dependent increases in triglyceride (TG) content in feces were observed in the HF + SKE groups. Since we confirmed that SKE inhibits lipase in vitro, these findings indicate that SKE suppresses the hydrolysis of TG by inhibiting lipase activity in the intestinal tract, thereby restricting the absorption of lipids, increasing the excretion of TG in feces, and suppressing the increase in body weight and visceral fat caused by the high-fat diet.
Kefir is an ancient beverage obtained from sugar solution fermentation of kefir grains with lactic and acetic-acid bacteria and yeasts with different probiotic properties. The aim of this work was to study the microbial composition of kefir grown in three different substrates; brown sugar, purified molasses, and high-test molasses. Antioxidant activity, angiotensin converting enzyme-inhibitory (ACE-inhibitory) activity, and antibacterial activity were also evaluated. Counts of lactic acid and acetic acid bacteria and yeasts did not change significantly in the tests; however, the microbial diversity changed depending on the media and fermentation periods used. Some of the species identified were isolated for the first time in kefir beverage (Acetobacter indonesiensis, Acetobacter tropicalis, Gluconobacter oxydans, Lactobacillus farraginis, Oenococcus kitaharae, and Pichia occidentalis). In addition, three media showed ACE-inhibitory activity, which increased after fermentation. Antioxidant and ion-chelating activities decreased after the fermentation of sugar solutions. Three fermentation solutions showed antibacterial activity against Escherichia coli, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus.
Barley miso (Japanese soybean paste) is generally classified into either the light-colored type or the red type based on a short or long maturation time, respectively. In this study, we characterized barley miso with a focus on its koji-like smell. Sensory evaluation showed that koji-like smell was significantly reduced during the maturation process, especially after two months. However, comprehensive analysis of volatile compounds indicated that known constituents of koji-like smell, 1-octen-3-ol and phenylacetaldehyde, were present in similar and lower concentrations, respectively, in the light-colored barley miso compared to the red barley miso. In addition, most compounds, such as aldehydes and esters, were found in larger concentrations in the red barley miso than in the light-colored barley miso. These results suggest that maturation time has an important role in koji-like smell, and the contributions of decreases in 1-octen-3-ol and phenylacetaldehyde to koji-like smell during the maturation process remains unclear.
The aim of this work was to evaluate the antioxidant activity and antimicrobial activity of gelatin edible films incorporated in rosemary essential oil (REO). The essential oil of two varieties of rosemary leaves (Rosmarinus officinalis L. var. Typicus and Troglodytarum) was extracted by hydro-distillation method. The antioxidant activity of REO was investigated using DPPH and β-carotene bleaching assays, and REO compounds were identified and quantified using GC-MS. REO has been incorporated into a biopolymer with gelatin and the antibacterial activity against Escherichia coli was determined using disc diffusion method for both REO and edible film with REO. REO extracted from Typicus variety was characterized with higher antioxidant activity, β-carotene and antimicrobial activity, than Troglodytarum variety. However, when the REO was incorporated in gelatin film lower antimicrobial activity were observed in comparison to rosemary essential oils.
Acid- and pepsin-soluble collagens (ASC and PSC) from scales of carp and lizardfish from temperate and sub-tropical countries were studied in regard to thermostability. SDS-PAGE revealed that ASC and PSC were classified as type I collagen, and the molecular weight of ASC was greater than that of PSC. Both types of collagen from sub-tropical fish scales contained greater imino acids compared to those from temperate fish scales. Carp from Japan and Bangladesh showed similar thermal stability, but lizardfish from Vietnam showed higher stability than lizardfish from Japan for both collagen types. Overall, PSC possessed a slightly lower denaturation temperature than the corresponding ASC, suggesting that a relationship between thermostability and the molecular mass of collagen, as observed in SDS-PAGE, might exist. Maximal solubility was noticed at acidic pH (1-4) and solubility obviously declined at a high salt concentration (>2%). ASC and PSC from these fish scales could be applicable to the food industry in place of mammalian collagens.