Kurosu,a Traditional Vinegar Produced from Unpolished Rice,Suppresses Lipid Peroxidation in Vitro and in Mouse Skin

The in vitro antioxidative activities of various kinds of vinegar were investigated by using a linoleic acid autoxidation model detected by the thiobarbituric acid (TBA) method and the 1,1-diphenyl-2-picrylhydrazyl radical system. An ethyl acetate extract of Kurosu (EK), a vinegar made from unpolished rice, exhibited the highest antioxidative activity in both systems. EK (5 mg) inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema formation (14%) and myeloperoxidase activity (52%, P<0.01) in female ICR mouse skin. Furthermore, EK significantly suppressed double TPA application-induced H₂O₂ generation (53%, P<0.01) and lipid peroxidation determined by the TBA-reacting substance level (95%, P<0.01). In a two-stage carcinogenesis experiment with dimethylbenz[a]anthracene/TPA, EK significantly reduced the number of tumors per mouse by 36% (P<0.05) at 15 weeks after promotion. These results suggest that the antitumor-promoting effect may be partially due to the antioxidative properties of EK such as the decomposition of free radicals and interference with free radical-generating leukocytes.     

Succession of Selected Strains of Acetobacter pasteurianus and Other Acetic Acid Bacteria in Traditional Balsamic Vinegar

The application of a selected Acetobacter pasteurianus strain for traditional balsamic vinegar production was assessed. Genomic DNA was extracted from biofilms after enrichment cultures on GYC medium (10% glucose, 1.0% yeast extract, 2.0% calcium carbonate) and used for PCR/denaturing gradient gel electrophoresis, 16S rRNA gene sequencing, and enterobacterial repetitive intergenic consensus/PCR sequencing. Results suggested that double-culture fermentation is suitable for traditional balsamic vinegar acetification.The use of selected starter cultures (SSC) in fermented food production is widely applied throughout the food industry, in particular for wine, dairy products, sausages, and a variety of vegetables (3, 11). The advantages of their use are related to the improvement of the process control, hygiene, and quality with respect to fermented foods obtained through indigenous fermentation. Vinegar is one of the fermented beverages produced without SSC inoculation, in both small- and large-scale production, mainly for the following reasons: (i) the majority of vinegars have low commercial value, and often technological innovation is not considered profitable, and (ii) there is limited knowledge of the ecophysiology of acetic acid bacteria (AAB) due to the difficulty in accessing, sampling, isolating, and preserving strains (2, 12, 15, 16, 17). Among vinegars, traditional balsamic vinegar (TBV) is an Italian aged condiment produced by “seed vinegar,” the so-called “mother of vinegar” that is an indigenous starter culture withdrawn from acetifying vinegar through back-slopping procedures. The raw material is a fermented and cooked grape must (here indicated as must) at a soluble solids content ranging from 20 to 60°Bx (10). TBV production is regulated by denomination of protected origin guidelines that specify procedures and final product features. In particular, the raw material characteristics, the production process (e.g., must cooking, alcoholic fermentation, acetic oxidation, and ageing), features of the production area (no environmental condition management is permitted), and analytical and sensorial parameters are stated as follows: acidity (not less than 4.5% [wt/wt], expressed as grams of acetic acid per 100 g of product), density at 20°C (not less than 1.240 g per liter), color, aroma, and taste. The production is performed in wood barrels, and the process is carried out by sequential refilling to acetify the must and replace the volume lost by evaporation. AAB grow on the surface of liquid by biofilm formation. No addition of any substance can be made except for the acetifying must as a starter (7). Microbial studies of TBV reported culture-dependent and -independent approaches to evaluating AAB occurrence in TBV musts (5, 10). These studies highlighted the occurrence of Gluconacetobacter europaeus as a widespread indigenous species, as well as Acetobacter pasteurianus, Acetobacter aceti, and Acetobacter malorum. However, no comprehensive studies of AAB diversity and the correlation between species occurrence and technological steps of TBV production have been published, due mainly to the difficulty of easy access to AAB microflora in vinegar matrix by both culture-dependent and -independent approaches.Regarding production technology, at least one drawback of current production procedures has been acknowledged. It concerns the difficulty of start-up acetification, which affects the minimum acidity value required for the final product. In fact, some studies showed that many variables regulate AAB growth and activity. Above all is the sugar concentration among substrates and the temperature among physical parameters. To efficiently control the acetification start-up, it is necessary to understand the function of AAB responsible for the initial colonization of musts and to investigate the microbial succession suitable to complete the acetification. Our previous researches on TBV showed that AAB strains exhibit different growing abilities. In particular, strains of Acetobacter pasteurianus grow quickly on laboratory synthetic media, wine, and cooked must. In contrast, strains belonging to G. europaeus do not grow or grow very slowly on cooked and fermented must (9, 10).The goal of this study was to implement a laboratory SSC to test it on a factory scale for TBV production purposes. In particular, we focused our attention on the effect of A. pasteurianus strain AB0220 on the acetification and dynamics of species at the end of the process. The SSC effectiveness was assessed by monitoring analytical parameters (acetic acid, ethanol, and pH), species succession, and strain persistence during three stages by the following molecular analyses: PCR/denaturing gradient gel electrophoresis (DGGE), 16S rRNA gene sequencing, and enterobacterial repetitive intergenic consensus (ERIC)/PCR sequencing using genomic DNA extracted from biofilms recovered on GYC (10% glucose, 1.0% yeast extract, 2.0% calcium carbonate) plates.     

Isolation and Identification of Acetic Acid Bacteria for Submerged Acetic Acid Fermentation at High Temperature

Industrial vinegar production by submerged acetic acid fermentation has been carried out using Acetobacter strains at about 30°C. To obtain strains suitable for acetic acid fermentation at higher temperature, about 1,100 strains of acetic acid bacteria were isolated from vinegar mash, soils in vinegar factories and fruits, and their activities to oxidize ethanol at high temperature were examined. One of these strains, No. 1023, identified as Acetobacter aceti, retained full activity to produce acetic acid in continuous submerged culture at 35°C and produced 45% of activity at 38°C, while the usual strain of A. aceti completely lost its activity at 35°C. Thus the use of this strain may reduce the cooling costs of industrial vinegar production.     

Evolution of Acetic Acid Bacteria During Fermentation and Storage of Wine

Acetic acid bacteria were present at all stages of wine making, from the mature grape through vinification to conservation. A succession of Gluconobacter oxydans, Acetobacter pasteurianus, and Acetobacter aceti during the course of these stages was noted. Low levels of A. aceti remained in the wine; they exhibited rapid proliferation on short exposure of the wine to air and caused significant increases in the concentration of acetic acid. Higher temperature of wine storage and higher wine pH favored the development and metabolism of these species.     

Dynamics and Biodiversity of Populations of Lactic Acid Bacteria and Acetic Acid Bacteria Involved in Spontaneous Heap Fermentation of Cocoa Beans in Ghana

The Ghanaian cocoa bean heap fermentation process was studied through a multiphasic approach, encompassing both microbiological and metabolite target analyses. A culture-dependent (plating and incubation, followed by repetitive-sequence-based PCR analyses of picked-up colonies) and culture-independent (denaturing gradient gel electrophoresis [DGGE] of 16S rRNA gene amplicons, PCR-DGGE) approach revealed a limited biodiversity and targeted population dynamics of both lactic acid bacteria (LAB) and acetic acid bacteria (AAB) during fermentation. Four main clusters were identified among the LAB isolated: Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc pseudomesenteroides, and Enterococcus casseliflavus. Other taxa encompassed, for instance, Weissella. Only four clusters were found among the AAB identified: Acetobacter pasteurianus, Acetobacter syzygii-like bacteria, and two small clusters of Acetobacter tropicalis-like bacteria. Particular strains of L. plantarum, L. fermentum, and A. pasteurianus, originating from the environment, were well adapted to the environmental conditions prevailing during Ghanaian cocoa bean heap fermentation and apparently played a significant role in the cocoa bean fermentation process. Yeasts produced ethanol from sugars, and LAB produced lactic acid, acetic acid, ethanol, and mannitol from sugars and/or citrate. Whereas L. plantarum strains were abundant in the beginning of the fermentation, L. fermentum strains converted fructose into mannitol upon prolonged fermentation. A. pasteurianus grew on ethanol, mannitol, and lactate and converted ethanol into acetic acid. A newly proposed Weissella sp., referred to as “Weissella ghanaensis,” was detected through PCR-DGGE analysis in some of the fermentations and was only occasionally picked up through culture-based isolation. Two new species of Acetobacter were found as well, namely, the species tentatively named “Acetobacter senegalensis” (A. tropicalis-like) and “Acetobacter ghanaensis” (A. syzygii-like).     

Antihypertensive Effects of Acetic Acid and Vinegar on Spontaneously Hypertensive Rats

To clarify the possibility of a preventive effect of dietary vinegar on blood pressure, long-term administration of vinegar or the acetic acid to SHR was examined. As a result, it was observed that acetic acid itself, the main component of vinegar, significantly reduced both blood pressure (p<0.05) and renin activity (p<0.01) compared to controls given no acetic acid or vinegar, as well as vinegar. There were no significant differences in angiotensin I-converting enzyme activity in various organs. As for the mechanism of this function, it was suggested that this reduction in blood pressure may be caused by the significant reduction in renin activity and the subsequent decrease in angiotensin II. From this study, it was also suggested that the antihypertensive effect of vinegar is mainly due to the acetic acid in it.     

广西传统发酵米粉中乳酸菌的分离鉴定

对广西传统米粉发酵液中的乳酸菌进行分离筛选,获得6株纯培养优势菌株。通过形态学鉴定及16S rDNA序列分析,结果表明其中4株乳酸菌属于戊糖片球菌(Pediococcus pentosaceus),另外2株鉴定为植物乳杆菌(Lactobacillus plantarum)。这2种乳酸菌均为对人类及动物安全的益生菌,该结果将为传统发酵米粉中有益微生物资源的挖掘和利用奠定基础。     

Microbiological and Biochemical Characterization of Cassava Retting, a Traditional Lactic Acid Fermentation for Foo-Foo (Cassava Flour) Production

The overall kinetics of retting, a spontaneous fermentation of cassava roots performed in central Africa, was investigated in terms of microbial-population evolution and biochemical and physicochemical parameters. During the traditional process, endogenous cyanogens were almost totally degraded, plant cell walls were lysed by the simultaneous action of pectin methylesterase and pectate lyase, and organic acids (C(inf2) to C(inf4)) were produced. Most microorganisms identified were found to be facultative anaerobes which used the sugars (sucrose, glucose, and fructose) present in the roots as carbon sources. After 24 h of retting, the fermentation reached an equilibrium that was reproducible in all the spontaneous fermentations studied. Lactic acid bacteria were largely predominant (over 99% of the total flora after 48 h) and governed the fermentation. The epiphytic flora was first replaced by Lactococcus lactis, then by Leuconostoc mesenteroides, and finally, at the end of the process, by Lactobacillus plantarum. These organisms produced ethanol and high concentrations of lactate, which strongly acidified the retting juice. In addition, the rapid decrease in partial oxygen pressure rendered the process anaerobic. Strict anaerobes, such as Clostridium spp., developed and produced the volatile fatty acids (mainly butyrate) responsible, together with lactate, for the typical flavor of retted cassava. Yeasts (mostly Candida spp.) did not seem to play a significant role in the process, but their increasing numbers in the last stage of the process might influence the flavor and the preservation of the end products.     

Phytotoxicity of Acetic Acid Produced in the Anaerobic Decomposition of Wheat Straw

Wheat straw was subjected to aerobic and anaerobic decomposition in suspensions of soil. The products of the aerobic process stimulated the root extension of barley seedlings, whereas the anaerobic fermentation yielded products which inhibited growth. Acetic acid was the phytotoxin present in the greatest amount.     

Influence of Turning and Environmental Contamination on the Dynamics of Populations of Lactic Acid and Acetic Acid Bacteria Involved in Spontaneous Cocoa Bean Heap Fermentation in Ghana

The influence of turning and environmental contamination on six spontaneous cocoa bean heap fermentations performed in Ghana was studied through a multiphasic approach, encompassing both microbiological (culture-dependent and culture-independent techniques) and metabolite target analyses. A sensory analysis of chocolate made from the fermented, dried beans was performed as well. Only four clusters were found among the isolates of acetic acid bacteria (AAB) identified: Acetobacter pasteurianus, Acetobacter ghanensis, Acetobacter senegalensis, and a potential new Acetobacter lovaniensis-like species. Two main clusters were identified among the lactic acid bacteria (LAB) isolated, namely, Lactobacillus plantarum and Lactobacillus fermentum. No differences in biodiversity of LAB and AAB were seen for fermentations carried out at the farm and factory sites, indicating the cocoa pod surfaces and not the general environment as the main inoculum for spontaneous cocoa bean heap fermentation. Turning of the heaps enhanced aeration and increased the relative population size of AAB and the production of acetic acid. This in turn gave a more sour taste to chocolate made from these beans. Bitterness was reduced through losses of polyphenols and alkaloids upon fermentation and cocoa bean processing.     

Fermentation of Fructooligosaccharides by Lactic Acid Bacteria and Bifidobacteria

Lactic acid bacteria and bifidobacteria were screened of their ability to ferment fructooligosaccharides (FOS) on MRS agar. Of 28 strains of lactic acid bacteria and bifidobacteria examined, 12 of 16 Lactobacillus strains and 7 of 8 Bifidobacterium strains fermented FOS. Only strains that gave a positive reaction by the agar method reached high cell densities in broth containing FOS.     

Characterization,Identification and Application of Lactic Acid Bacteria Isolated from Forage Paddy Rice Silage

There has been growing interest to develop forage rice as a new feed resource for livestock. This study was to characterize the natural population of lactic acid bacteria (LAB) and select potentially excellent strains for paddy rice silage preparation in China. One hundred and twenty-six strains were isolated and screened from paddy rice silage prepared using a small-scale fermentation system, and ninety-nine of these isolates were considered to be LAB based on their Gram-positive and catalase-negative morphology and the production of most of their metabolic products as lactic acid. These isolates were divided into eight groups (A-H) on the basis of their morphological and biochemical characteristics. The Group A to H strains were identified as Lactobacillus (L.) plantarum subsp. plantarum (species ratio: 8.1%), L. casei (5.1%), Leuconostoc (Ln.) pseudomesenteroides (11.1%), Pediococcus (P.) pentosaceus (24.2%), Enterococcus (E.) mundtii (12.1%), Lactococcus (Lc.) garvieae (15.2%), E. faecium (9.1%) and Lc. lactis subsp. lactis (15.2%) based on sequence analyses of their 16S rRNA and recA genes. P. pentosaceus was the most abundant member of the LAB population in the paddy rice silage. A selected strain, namely L. casei R 465, was found to be able to grow under low pH conditions and to improve the silage quality with low pH and a relatively high content of lactic acid. This study demonstrated that forage paddy rice silage contains abundant LAB species and its silage can be well preserved by inoculation with LAB, and that strain R 465 can be a potentially excellent inoculant for paddy rice silage.     

Transformation of Citric Acid to Acetic Acid,Acetoin and Diacetyl by Wine Making Lactic Acid Bacteria

A decrease in citric acid and increases in acetic acid, acetoin and diacetyl were found in the test red wine after inoculation of intact cells of Leuconostoc mesenteroides subsp. lactosum ATCC 27307. a malo-lactic bacterium, grown on the malate plus citrate-medium. Citric acid in the buffer solution was transformed to acetic acid, acetoin and diacetyl in the pH range of 2 to 6 after inoculation with intact cells of this bacterial species. It was concluded that citric acid in wine making involving malolactic fermentation, at first, was converted by citrate lyase to acetic and oxaloacetic acids, and the latter was successively transformed by decarboxylation to pyruvic acid which was subsequently converted to acetoin, diacetyl and acetic acid.

Both the activities of citrate lyase and acetoin formation from pyruvic acid in the dialyzed cell-free extract were optimal at pH 6.0. Divalent cations such as Mn²⁺, Mg²⁺, Co²⁺ and Zn²⁺ activated the citrate lyase. The citrate lyase was completely inhibited by EDTA, Hg²⁺ and Ag²⁺ . The acetoin formation from pyruvic acid was significantly stimulated by thiamine pyrophosphate and CoCl₂, and inhibited by oxaloacetic acid. Specific activities of the citrate lyase and acetoin formation were considerably variable among the six strains of malo-lactic bacteria examined. Some activities of irreversible reduction of diacetyl to acetoin were found in the cell-free extracts of four of the malo-lactic bacteria strains and the optimal pH was 6.0 for this activity of Leu. mesenteroides.     

Stereoisomeric Characterization of Tartaric Acid Produced during l-Ascorbic Acid Metabolism in Plants

Labeled tartaric acids from Pelargonium crispum apices which had been fed l-ascorbic acid-6-(14)C and Vitis labrusca and Parthenocissus inserta tissues which had been fed l-ascorbic acid-1-(14)C were examined by chemical means to determine chiral configuration. In each instance, label was associated with (+)-tartaric acid.Similar experiments with labeled tartaric acid from P. crispum which had been labeled with d-glucose-1-(14)C or -6-(14)C led to the same result. No evidence was obtained for formation of labeled meso-tartaric acid in experiments described above. The recent suggestion of H. Ruffner and D. Rast (Z. Pflanzenphysiol. 73: 45-55, 1974) that conversion of l-ascorbic acid to tartaric acid in plants is a nonenzymatic process is re-examined in the light of present findings.     

Coupling of Fermentation and Esterification: Microbial Esterification of Decanoic Acid with Ethanol Produced via Fermentation

Two different kinds of bioprocess, ethanol fermentation and subsequent microbial esterification, were coupled using Issatchenkia terricola IFO 0933 in an interface bioreactor. The strain produced ethyl decanoate (Et-DA) by esterification of exogenous decanoic acid (DA) with ethanol produced via fermentation. The efficiency of the new coupling system depended on the concentration of glucose in a carrier and DA in an organic phase (decane) in an agar plate interface bioreactor. Optimum glucose content and DA concentration were 4% and 29 mM, respectively.     

Characterization and Antibacterial Activity Against Helicobacter pylori of Lactic Acid Bacteria Isolated from Thai Fermented Rice Noodle

Probiotics and Antimicrobial Proteins - A total of 32 lactic acid bacteria (LAB) were isolated from Khanom-jeen, a Thai traditional fermented rice noodle. They belonged to the genus Leuconostoc...     

Biochemical and Molecular Characterization of Potential Phosphate-Solubilizing Bacteria in Acid Sulfate Soils and Their Beneficial Effects on Rice Growth

A study was conducted to determine the total microbial population, the occurrence of growth promoting bacteria and their beneficial traits in acid sulfate soils. The mechanisms by which the bacteria enhance rice seedlings grown under high Al and low pH stress were investigated. Soils and rice root samples were randomly collected from four sites in the study area (Kelantan, Malaysia). The topsoil pH and exchangeable Al ranged from 3.3 to 4.7 and 1.24 to 4.25 cmol_c kg⁻¹, respectively, which are considered unsuitable for rice production. Total bacterial and actinomycetes population in the acidic soils were found to be higher than fungal populations. A total of 21 phosphate-solubilizing bacteria (PSB) including 19 N₂-fixing strains were isolated from the acid sulfate soil. Using 16S rRNA gene sequence analysis, three potential PSB strains based on their beneficial characteristics were identified (Burkholderia thailandensis, Sphingomonas pituitosa and Burkholderia seminalis). The isolated strains were capable of producing indoleacetic acid (IAA) and organic acids that were able to reduce Al availability via a chelation process. These PSB isolates solubilized P (43.65%) existing in the growth media within 72 hours of incubation. Seedling of rice variety, MR 219, grown at pH 4, and with different concentrations of Al (0, 50 and 100 µM) was inoculated with these PSB strains. Results showed that the bacteria increased the pH with a concomitant reduction in Al concentration, which translated into better rice growth. The improved root volume and seedling dry weight of the inoculated plants indicated the potential of these isolates to be used in a bio-fertilizer formulation for rice cultivation on acid sulfate soils.     

杆菌肽产生菌的分离鉴定及其发酵条件初步研究

杆菌肽在畜牧养殖业中应用广泛,开展菌种筛选工作十分必要。以低浓度杆菌肽为筛选方法,分离得到一株杆菌肽产生菌,鉴定并命名为地衣芽孢杆菌Y822(Bacillus licheninformis Y822)。该菌株发酵生产杆菌肽时,最适p H为7.0,溶氧能够促进产物肽积累。将B.licheninformis Y822传代5次,分别进行发酵试验,可得到(783.51±7.34)U/m L杆菌肽,其中A组分占(75.04±0.83)%。B.licheniformis Y822杆菌肽产量较高,生产能力稳定,并且产物中杆菌肽A组分含量高,具有较高的工业应用价值。