Thirty-five predominant lactic acid bacteria (LAB) were isolated from six samples of traditional Mongolian Airag (fermented mare's milk) collected in four provinces near Ulaanbaatar, and the bacteria were classified into ten types of LAB by 16S rDNA sequencing. Two types of yeast were also isolated and identified by 26S rDNA sequencing. Two supernatants produced by Lactobacillus hilgardii (Uvu-21) and L. diolivorans (Tuv-33) were found to have potent antibacterial and proteolytic activities, with high thermal and wide pH range stabilities. The activities disappeared after protease treatment, suggesting that the biological activity originated from peptides produced by the LAB. In addition, the fermentation ability of the yeasts was weaker than that of K7 yeast used in sake brewing. These results provide useful information about Airag as a healthy daily beverage in Mongolia.
Fuzzy mathematics was applied to comprehensively evaluate the sensory quality of instant sea cucumber. Color, flavor, and fleshy elasticity were the evaluation factors considered and given with appropriate weights. The optimal conditions for instant sea cucumber were determined using single-factor and response surface methodology. The optimum processing parameters were as follows: cooking time, 60 min; cooking temperature, 83°C; water-swelling time, 42.5 h; and seasoning concentration, 100%. Under these conditions, the sensory evaluation score was 94.28, which matched well with the predicted value. Moreover, instant sea cucumber can keep its various nutritional values better. It is also found to have a better and nutritionally more beneficial amino acid composition than commercial sea cucumber.
Paocai was a traditional fermented food in China and produced by spontaneous fermentation of various vegetables. The microbial community occurring in industrial matured Chinese paocai (IMCP) from different factories was investigated by PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR). The dominant bacteria were different in IMCP from different factories. Three genera including Debaryomyces, Pichia and Candida were identified and Debaryomyces was mutual and dominant yeast in all IMCP. Fifteen bands from DGGE profiles of lactic acid bacteria (LAB) were identified and four genera were detected. Alkalibacterium and Lactobacillus were dominant in all IMCP. In conclusion, the IMCP from different factories possessed different dominant bacteria. The community of LAB in IMCP from different factories was different, and Lactobacillus and Alkalibacterium were main LABs in all IMCP. The quantity of LAB was quantitated and shown to exist at 107 – 109 copies in the IMCP from different factories.
In recent years, food consumption trends in Japan have been changed greatly by the “westernization of the meal”. In particular, the increased consumption of dairy products and decreased consumption of rice are remarkable. Thus, we investigated the possibility of producing a cheese-like food from rice milk. Rice milk was pasteurized, fermented by lactic acid bacteria (LAB), and coagulated with various coagulation agents. Several heating conditions were applied for pasteurization of the rice milk, and the most rapid and efficient condition was achieved when the rice milk was heated at 65°C for 30 min. After fermentation, the population of LAB and pH of the fermented rice milk were found to be similar to those of fermented dairy milk. Some samples went through a dehydration step before coagulation with gelatin, xanthan gum, or agar. The dehydrated samples containing gelatin were similar in breaking strength to standard dairy cheese, and thus were used in sensory evaluation. In the sensory test, the sample containing 2.5 wt% gelatin received the highest overall acceptance of 41.6%.
The aim of the present study was to investigate the effects of Lepidium meyenii (maca) on hypoxia tolerance and fatigue relief, and to determine its active constituents. The results showed that, in the mouse model, maca powder could significantly prolong hypoxia time (HT) and forced swim time (FST) and optimize blood sugar ratio (BSR), liver glycogen (LG), muscle glycogen (MG), blood lactic acid, and lactic dehydrogenase. Based on these results, aqueous extracts and maca water-soluble polysaccharide (MWP) were isolated. The total sugar content of MWP is 90.41 ± 2.55%, and the main monosaccharide component is glucose (79.88%). In the mouse model, HT (40.76 ± 7.97 min), FST (48.32 ± 10.76 min), BSR (4.49 ± 4.04%), LG (11.27 ± 0.61 mg/g), and MG (1.45 ± 0.17 mg/g) were all significantly enhanced in groups given maca powder compared to the control group (p < 0.05). In summary, maca is effective in improving hypoxia tolerance and relieving fatigue, and MWP is the active substance.
Previous studies suggested that peptide absorption by peptide transporter 1 (PepT1) contributes to water absorption in the small intestine. Here, we aimed to apply this effect of peptides to a rehydration drink for the effective treatment of dehydration. We first prepared a whey peptide drink (WPD) in which the composition (whey peptides and Na+) was optimized for water absorption in the small intestine. We then evaluated the effectiveness of the WPD in an in vivo dehydration model. The results demonstrated the following: (1) the addition of whey peptides to a carbohydrate-electrolyte drink enhanced the rehydration effect in the rat dehydration model, i.e., it increased the plasma volume more quickly and more abundantly; and (2) the WPD was more effective for rehydration than a general sports drink. The WPD could be considered a new treatment option for the rapid alleviation of dehydration.
Whey protein consumption is reported to reduce serum lipids, however the responses to derived peptides have not yet been fully characterized. In this study, we evaluated the effects of whey protein-hydrolyzed peptides (WPP) on serum and hepatic lipid levels, as well as hepatic lipogenic gene expression in SD rats consuming a high-sucrose AIN-76 based diet. After a 14-day ad libitum consumption of diet containing WPP, serum and hepatic triglycerides, and total cholesterol levels were significantly decreased when compared with the control group. A similar trend was observed in the time-restricted feeding groups, in which food was provided for 2 h at the beginning and the end of the dark period cycle during the 14-day treatment period. Additionally, hepatic gene expression linked to triglyceride and cholesterol biosynthesis, and their enzymatic activities were downregulated in the WPP group. In conclusion, daily consumption of WPP appears to decrease lipid levels in the blood and liver, and potentially protect against dyslipidemia.
Sodium ferric gluconate complex (SFGC) was synthesized by a simple method using D-sodium gluconate (D-SG) and ferric chloride as raw materials, which was found to have chelated iron characteristics by measuring its physicochemical properties. The iron(III) complex was characterized by scanning electron microscopy (SEM), ultraviolet-visible spectrophotometry (UV-Vis), fourier transform infrared (FTIR), X-ray diffraction analysis (XRD) and differential scanning calorimetry (DSC). The results verified that the product was indeed the chelated iron complexes and its iron core was composed of iron oxyhydroxide namely β-FeOOH mineral polymorph. Moreover, antioxidant activity of SFGC was evaluated by the half maximal inhibitory concentration (IC50) against hydroxyl free radical, 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical, nitrite and lipid peroxidation, and their values were 3.65, 8.09, 3.01, 1.90 mg/mL, respectively. These results demonstrate that SFGC is expected to become a good iron supplement with a variety of biological activity or food additive strengthening iron.
Maoberry (Antidesma bunius L.) juice is popularly consumed as a pasteurized juice because of its high levels of antioxidants. Although pasteurization is normally applied to extend the shelf life of fruit juices, this method damages the desired characteristics and antioxidant constituents of fruit juice products. Ultra-sonication is an alternative process to treat fruit juices without impairing their health benefits and consumer acceptance. This study is the first report on ultra-sonication effects on the physicochemical properties, bioactive components, antioxidant activities, and sensorial characteristics of maoberry juice. After ultra-sonication processing at a frequency of 20 kHz and amplitude levels between 20% and 80% for 30 min and when compared with fresh and heated (75°C, 30 min) juices, we found that the physicochemical properties viz. total soluble solids, pH, and viscosity of processed juices did not change. However, a noticeable effect on the color parameters of ultra-sonicated juices shown by decreased lightness and increased redness values was found. The highest chroma value (C*) and total different colors (ΔE) were observed in the heated one. Microbial count levels, polyphenol oxidase and peroxidase activities were low in all treatments, in particular thermally and 80% amplitude treated batches. Total anthocyanins and phenolic compounds increased in the ultra-sonicated maoberry juices treated at 60% and 80% amplitudes. The contents of ascorbic acid in maoberry juice decreased significantly at 80% amplitude and at 75°C. The antioxidant activities (DPPH and FRAP assays) of ultra-sonicated products still retained high levels with no significant difference from the fresh sample. The sensorial attributes of ultra-sonicated juice showed no difference from the control (fresh juice), but higher than the heated sample. In general, ultra-sonication technology could be an appropriate processing technique to maintain the desired quality attribute characteristics of maoberry juice.
Glycogen branching enzyme contributes to the process of glycogen synthesis by creating α (1→6) branches through cleaving the α-1, 4-glycosidic bonds. An intracellular glycogen branching enzyme (named PsGBE) from Paenibacillus sp. SSG-1 was cloned and expressed. The recombinant enzyme was purified by metal-affinity chromatography, exhibited a molecular mass of 84.9 kDa. PsGBE was optimally active at pH 6.6 and 35°C. PsGBE showed high specificity to amylose, soluble starch and amylopectin. PsGBE could attack and change the structures of starch granules. Addition of PsGBE (40 U/100 g of flour) to wheat bread increased specific volume (5.85 mL/g) and decreased crumb firmness (8.16 N) during bread storage. In addition, PsGBE could significantly retard the retrogradation and improve the quality of bread. Therefore, these properties make PsGBE highly potential application in the starch-related industries.
Wasabi is a plant of Japanese origin belonging to the Brassicaceae family. Although the wasabi rhizome is a popular condiment in Japan, the leaf is typically discarded. For utilization of the wasabi leaf, we investigated its anti-obesity effect on Wistar rats fed a high-fat diet containing wasabi leaf extract (WLE) prepared with 50% ethanol. At the experimental endpoint, WLE had significantly decreased the body weight of rats and upregulated the mRNA expression of the β3-adrenergic receptor (Adrb3) in the interscapular brown adipose tissue (BAT). WLE may have promoted lipid absorption from the dietary fat, as the fecal lipid content was considerably lower in the WLE group. These results suggest that WLE suppressed obesity in rats fed a high-fat diet, which was related to the upregulation of Adrb3 mRNA expression in the interscapular BAT without increased fecal lipid excretion. Thus, wasabi leaves may be used as a functional food material for the suppression of obesity.
Tofu-misozuke is a traditional fermented food in Japan, and contains biogenic amines that function as neurotransmitters, but are toxic when consumed at high levels. Analysis of the amine production of bacterial communities is important for controlling the amine content in fermented foods. We investigated the bacterial community and biogenic amine content of tofu-misozuke. The lactic acid bacteria (LAB) ratio in the community and tyramine content were highly related. LAB were isolated to identify the biogenic amine-producing species. Isolated strains from tofu-misozuke were identified, and their tyramine formation potential was evaluated by PCR detection of the tyrosine decarboxylase gene and by cultivation tests. We detected three tyramine-producing bacteria, Enterococcus faecium, Weissella viridescens, and Lactobacillus curvatus, in tofu-misozuke.
Ripened sweet rice wines (mirins) are stored at room temperature for several years to produce a well-balanced sweet flavor. We performed reverse-phase HPLC quantitative analysis of d-amino acids in eight ripened mirins by using derivatization reagents, and investigated the influence of the Maillard reaction on amino acid racemization in mirin during maturation. The relative quantities of d-enantiomers (%d) of Asp, Glu, and Ser in mirins matured for seven years or more were higher than in non-ripened mirins. Based on the calculated correlation coefficient between %D and the amount of Amadori rearrangement products (ARPs) analyzed by LC-MS in ripened mirins for each amino acid, Asp showed a statistically significant strong correlation. Finally, we conducted heating experiments using synthetic ARPs. Our results revealed for the first time that Asp was racemized via ARPs under the influence of pH during mirin maturation.
Starches from four processing type potato varieties, cultivated in two locations in Hokkaido prefecture of Japan were evaluated for the effects of variety and growing locations on their physicochemical properties. Amylose and phosphorous contents, average granule size, solubility, swelling power, thermal and pasting properties were evaluated. Pearson's correlation analysis and two-way ANOVA were applied and found that significant differences in amylose content, phosphorous content and average granule size were observed among the four varieties and between the two locations (p < 0.05). Swelling power and pasting properties were higher in starches from Kamikawa, while solubility was higher for starches from Tokachi. Higher T0 and TP observed for Kitahime in Kamikawa and T0, TP and TC for Andover and Snowden in Kamikawa suggest presence of more stable crystalline structures in starch granules grown in Kamikawa. Thus, variety and growing locations affected the starch properties, such as thermal and pasting properties significantly (p < 0.05).
Ease of swallowing blender-made rice gruel when half of the non-glutinous japonica rice is replaced with glutinous japonica or non-glutinous indica rice was evaluated by physical measurement and sensory evaluation. Sensory evaluation revealed that blender-made rice gruel containing non-glutinous indica rice was stickier than non-glutinous japonica rice gruel, and was evaluated as harder to swallow. Blender-made rice gruel containing glutinous japonica rice was less sticky than non-glutinous rice gruel and was evaluated as easier to swallow. Blender-made rice gruel containing glutinous japonica rice contains less amylose and, combined with the partial degradation of starch due to the α-amylase in the glutinous rice, results in reduced stickiness of the rice liquid, making the gruel easier to swallow.
To understand the effects of pretreatment of lettuce during cultivation with 0.001% ε-polylysine (PL) in combination with 0.25% milk serum protein (MSP) on the attachment of Salmonella Enteritidis, lettuce leaves were contaminated with S. Enteritidis after a 1-day treatment with food additives, and harvested after cultivation for 1 day. Viable S. Enteritidis counts on lettuce leaves pretreated with the PL and MSP mixture were significantly reduced from 5.7 log CFU/g to 1 log CFU/g after decontamination by washing with water and a subsequent treatment with NaClO. The viable S. Enteritidis counts on radish sprouts grown for 7 d in the presence of 0.01% PL from seeds inoculated with S. Enteritidis were reduced to 3.1 log CFU/50 sprouts after NaClO decontamination. These counts were significantly lower (P < 0.05) than those of plants without additive(s). The treatment with additive(s) did not affect the ascorbic acid and chlorophyll contents of both plants.
This study attempted to isolate bioactive compounds from niihime, a sour Citrus fruit, and to evaluate their bioactivity by simultaneously monitoring superoxide generation and intracellular calcium ion levels in neutrophils. Seven aromatic compounds were isolated from a methanol extract of niihime peel and identified as 6-demethoxynobiletin, 6-demethoxytangeretin, nobiletin, tangeretin, sinensetin, 5,7-dimethoxycoumarin, and saccharic acid 1,4-lactone 3,5-di-O-ferulate. 6-Demethoxynobiletin, 6-demethoxytangeretin, and 5,7-dimethoxycoumarin were newly shown to be contained in niihime fruit. Bioactivity assay of 10 µM saccharic acid 1,4-lactone 3,5-di-O-ferulate revealed a significant increase in both superoxide generation and intracellular calcium ion concentration (p<0.05). This result indicates that saccharic acid 1,4-lactone 3,5-di-O-ferulate has immunostimulatory activity in neutrophils.
We examined the effects of black rice (BR) (Oryza sativa L.) grains and an anthocyanin (AC) extract of the grains on lipid and carbohydrate metabolism and in vivo oxidative stress in type 2 diabetic mice. Mice (C57BL/KsJ-leprdb/leprdb, db/db) were fed an AIN-93G based diet containing 20% (w/w) boiled BR grains or the AC extract (0.015% or 0.03%, w/w) for 21 days. TBARS levels in the liver tissues of the BR- and AC-diet groups were lower than those of the diabetic control (DC) group. Concentrations of other parameters, such as plasma arteriosclerotic index, hepatic lipids, and total cholesterol in liver tissues in the AC-diet fed group were lower than those in the DC group, and tended to be lower in the BR-diet group than in the DC group. Fecal concentrations of bile acids and cholesterol were higher in the BR- and AC-diet fed groups than in the DC group. These results suggest that compounds in the AC extract contribute to the improvement of lipid metabolism and suppression of in vivo oxidative stress by ingestion of BR grains.