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PubMed2004

Production of fibrinolytic enzyme from soybean grits fermented by Bacillus firmus NA-1.

Bacillus firmus NA-1 producing fibrinolytic enzyme was isolated from Japanese traditional fermented soybean (Natto). Seed starter was cultured in 5% soy milk prepared with micronized soybean powder. To optimize the production of fibrinolytic enzyme, the soybean grits were mixed with 1 volume of water and sterilized at 121 degrees C for 5 minutes, and then used as the medium for solid-state fermentation at 42 degrees C. The fibrinolytic enzyme activity of the fermented grits was 1,120 plasmin units/100 g (wet weight) after fermentation for 24 hours. The water extract of the fermented grits showed the highest viscosity after fermentation for 12 hours. However, the tyrosine content was the highest (962 mg%) after fermentation for 60 hours. The color of raw soybean grit was affected by heat treatment. The activity of fibrinolytic enzyme was stable after freezing-drying, but was completely destroyed by heating at 70 degrees C for 10 minutes. The color of soybean grit was greatly darkened by increasing fermentation time. Soybean grits were completely converted into valuable functional ingredients containing fibrinolytic enzyme, peptide, and mucilage by the solid-state fermentation.

Bacillus↗

PubMed1995

The effect of fibre source and fermentation on the apparent hydrophobic binding properties of wheat bran preparations for the mutagen 2-amino-3,8- dimethylimidazo[4,5-f]quinoxaline (MeIQx).

Preparations of dietary fibre have an ability to bind potentially toxic compounds in vitro, but it is unclear how the measured binding properties are a reflection of either the relative affinity of such compounds for fibre or the saturation binding capacity of the fibre. Cooking and processing of foods and fermentation activity in the colon can result in significant modification of the structure of the fibre matrix. Hence, binding properties measured in vitro may be significantly altered from those at the proposed site of fibre activity. Using cell wall material (CWM) prepared from three distinct wheat fibre sources, the effects of fermentation have been monitored and the consequences on the binding properties assessed. The CWM preparations were feremented for either 0, 6, 18 or 24 h in vitro, using a human faecal inoculum. The coarse bran CWM was also subjected to a simulated gastric treatment. Fermentation resulted in a loss of material from each CWM preparation, the loss being consistent with the bran source, and the maximum extent of fermentation was reached within 18 h. The in vitro binding of the mutagen 2-amino-3,8- dimethylimidazo[4,5-f]quinoxaline (MeIQx) to the unfermented and fermented fibre fractions showed fine bran CWM had a much higher affinity for MeIQx than coarse bran. A 6 h fermentation had little effect on the binding affinity to fine bran, but the affinity for coarse bran became similar to that of the fine bran. Further fermentation for 18 h or 24 h resulted in a further slight increase in the binding affinity for coarse and fine bran, but, more significantly, the binding capacity of each was increased. The binding properties of the beeswing bran were not significantly affected by fermentation. Wheat bran has the potential to bind hydrophobic mutagens in the diet and this potential can be enhanced after fermentation under colonic conditions.

Animals↗

PubMed1997

The association of yogurt starters with Lactobacillus casei DN 114.001 in fermented milk alters the composition and metabolism of intestinal microflora in germ-free rats and in human flora-associated rats.

The aim of this study was to compare the effects of milk and of various fermented milks on the composition and metabolic activities of the intestinal microflora. Groups of eight rats were fed for 6 wk a diet containing 30% nonfermented milk (M), yogurt (Y), milk fermented with Lactobacillus casei (LcFM) or milk fermented with the association of L. casei DN 114.001 and yogurt starters (LcYFM). In the first study, the survival of the lactic acid bacteria from the fermented milks was assessed by bacterial enumeration in feces of germ-free rats (GF rats) fed milk or fermented milks. The metabolic activities of the lactic acid bacteria were studied in these rats by the measurement of glycolytic activities and products of bacterial fermentation, i.e., acetate and lactate (isoforms L and D). In a second study, the effects of fermented milks on the composition and metabolism [gas, glycolytic activities, short-chain fatty acids (SCFA), alcohol and ammonia] of human flora were studied using human flora-associated rats (HF rats). In GF rats, the survival of L. casei in the feces did not differ between those fed the LcFM and LcYFM diets. L. bulgaricus was detected in the feces of the rats fed Y, whereas Streptoccus thermophilus was found in the feces of the LcYFM group. In HF rats, fecal concentration of Bifidobacteria was greater in the LcFM group than in the others. beta-Glucuronidase (EC 3.2.1.31) activity was lower in rats fed LcFM and Y than in those fed M and LcYFM, whereas beta-galactosidase (3.2.1.23), alpha-glucosidase (EC 3.2.1 20) and beta-glucosidase (EC 3.2.1.21) activities were higher in the LcYFM group compared with the others. Methane excretion was higher in rats fed Y than in other groups. Cecal SCFA concentrations did not differ in LcFM, Y and M groups, but total SCFA, acetate, propionate and butyrate were significantly greater in the LcYFM group. These results suggest that milk fermented with the combination of L. casei and yogurt starters leads to specific effects that are different from the simple addition of the effects found with yogurt and milk fermented with L. casei. These specific effects are potentially beneficial to human health.

Acetates↗

PubMed2000

In vitro fermentation pattern of D-tagatose is affected by adaptation of the microbiota from the gastrointestinal tract of pigs.

Knowledge of the fermentation pattern of D-tagatose is important for the assessment of energy value and compliance of D-tagatose. In vitro fermentation experiments with pig intestinal contents and bacteria harvested from the gastrointestinal tract of pigs were used to investigate the degradation of D-tagatose and the formation of fermentation products. Two groups of eight pigs were fed either a control diet containing 150 g/kg sucrose or a diet which had 100 g/kg of the sucrose replaced by D-tagatose. After 18 d the pigs were killed and the gastrointestinal contents collected for in vitro studies. No microbial fermentation of D-tagatose occurred in the stomach or in the small intestine, whereas the sugar was fermented in the cecum and colon. Formate, acetate, propionate, butyrate, valerate, caproate and some heptanoate were produced by the microbial fermentation of D-tagatose by gut microbiota. Hydrogen and methane were also produced. The population of D-tagatose-degrading bacteria in fecal samples and the capacity of bacteria from the hindgut to degrade D-tagatose were higher in the pigs adapted to D-tagatose compared with unadapted pigs. In unadapted pigs, the major fermentation product from D-tagatose was acetic acid. Much more butyric and valeric acids were produced from D-tagatose by bacterial slurries of tagatose-adapted pigs compared with unadapted pigs; this was especially the case for samples from the colon. We conclude that D-tagatose is not fermented in the upper gastrointestinal tract, and the ability of the large intestinal microbiota to ferment D-tagatose is dependent on adaptation.

Acetic Acid↗

PubMed2004

The role of indigenous yeasts in traditional Irish cider fermentations.

AIMS: To study the role of the indigenous yeast flora in traditional Irish cider fermentations. METHODS AND RESULTS: Wallerstein laboratory nutrient agar supplemented with biotin, ferric ammonium citrate, calcium carbonate and ethanol was employed together with PCR-restriction fragment length polymorphism analysis of the region spanning the internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene in the identification of indigenous yeasts at the species level, from traditional Irish cider fermentations. By combining the molecular approach and the presumptive media it was possible to distinguish between a large number of yeast species, and to track them within cider fermentations. The Irish cider fermentation process can be divided into three sequential phases based on the predominant yeast type present. Kloeckera/Hanseniaspora uvarum type yeasts predominate in the initial 'fruit yeast phase'. Thereafter Saccharomyces cerevisiae type yeast dominate in the 'fermentation phase', where the alcoholic fermentation takes place. Finally the 'maturation phase' which follows, is dominated by Dekkera and Brettanomyces type yeasts. H. uvarum type yeast were found to have originated from the fruit. Brettanomyces type yeast could be traced back to the press house, and also to the fruit. The press house was identified as having high levels of S. cerevisiae type yeast. A strong link was noted between the temperature profile of the cider fermentations, which ranged from 22 to 35 degrees C and the yeast strain population dynamics. CONCLUSIONS: Many different indigenous yeast species were identified. The mycology of Irish cider fermentations appears to be very similar to that which has previously been reported in the wine industry. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has allowed us to gain a better understanding of the role of indigenous yeast species in 'Natural' Irish cider fermentations.

Alcoholic Beverages↗

PubMed2005

Upregulation of ALD3 and GPD1 in Saccharomyces cerevisiae during Icewine fermentation.

AIMS: To determine acetic acid, acetaldehyde and glycerol production by wine yeast throughout Icewine fermentation. The expression of yeast cytosolic aldehyde dehydrogenases (ALD3 and ALD6) and glycerol-3-phosphate dehydrogenase (GPD1) were followed to relate metabolites in the wines to expression patterns of these genes. METHODS AND RESULTS: Icewine juice (38.8 degrees Brix, 401 +/- 7 g l(-1) sugar), diluted Icewine juice (21.3 degrees Brix, 211 +/- 7 g l(-1) sugar) and the diluted juice with sugar levels equal to the original Icewine juice (35.6 degrees Brix, 402 +/- 6 g l(-1) sugar) were fermented in triplicate using the commercial wine yeast K1-V1116. Acetic acid production increased 7.1-fold and glycerol production increased 1.8-fold in the Icewine fermentation over that found in the diluted juice fermentation. ALD3 showed a 6.2-fold induction and GPD1 showed a 2.5-fold induction during Icewine vs the diluted fermentation. ALD3 was not glucose repressed when additional sugar was added to diluted juice, but was upregulated 7.0-fold. CONCLUSIONS: The NAD+-dependant aldehyde dehydrogenase encoded by ALD3 appears to contribute to acetic acid production during Icewine fermentation. Expression of GPD1 was upregulated in high sugar fermentations and reflects the elevated levels of glycerol. Solutes in Icewine juice in addition to sugar contribute to the yeast metabolic response. SIGNIFICANCE AND IMPACT OF THE STUDY: This work represents the first descriptive analysis of the fermentation of Canadian Icewine, the expression patterns of yeast genes involved in metabolite production, and their impact on Icewine quality. A role for ALD3 in acetic acid production during Icewine fermentation was found.

Acetaldehyde↗

PubMed2006

Managing high-density commercial scale wine fermentations.

AIMS: To investigate the effects of grape juice dilution and different temperature/nitrogen addition regimes on commercial-scale, high-density Shiraz and Chardonnay fermentations. METHODS AND RESULTS: Duplicated fermentations (30 hl) were conducted at two temperatures for Shiraz and for Chardonnay. Two additional tanks of Chardonnay and Shiraz were diluted. Nitrogen was added once at inoculation or in aliquots over several days. Yeast concentration and viability was determined by flow cytometry. Fermentation chemistry was monitored by Fourier transform infrared spectroscopy. Fermentations arrested in both of the undiluted, higher temperature duplicate tanks of Shiraz. Different fermentation temperature resulted in sensorially different Shiraz, but not Chardonnay, wines made from undiluted musts. The converse was observed for wines made from diluted musts. CONCLUSIONS: High-density musts can be fermented completely using reduced fermentation temperature coupled with incremental nitrogen addition. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study in duplicated, commercial-scale, high-density grape juice fermentations to address temperature, nitrogen addition, and juice dilution effects on stuck fermentation potential and wine sensory properties.

Commerce↗

PubMed2006

Isolation and characterization of brewer's yeast variants with improved fermentation performance under high-gravity conditions.

To save energy, space, and time, today's breweries make use of high-gravity brewing in which concentrated medium (wort) is fermented, resulting in a product with higher ethanol content. After fermentation, the product is diluted to obtain beer with the desired alcohol content. While economically desirable, the use of wort with an even higher sugar concentration is limited by the inability of brewer's yeast (Saccharomyces pastorianus) to efficiently ferment such concentrated medium. Here, we describe a successful strategy to obtain yeast variants with significantly improved fermentation capacity under high-gravity conditions. We isolated better-performing variants of the industrial lager strain CMBS33 by subjecting a pool of UV-induced variants to consecutive rounds of fermentation in very-high-gravity wort (>22 degrees Plato). Two variants (GT336 and GT344) showing faster fermentation rates and/or more-complete attenuation as well as improved viability under high ethanol conditions were identified. The variants displayed the same advantages in a pilot-scale stirred fermenter under high-gravity conditions at 11 degrees C. Microarray analysis identified several genes whose altered expression may be responsible for the superior performance of the variants. The role of some of these candidate genes was confirmed by genetic transformation. Our study shows that proper selection conditions allow the isolation of variants of commercial brewer's yeast with superior fermentation characteristics. Moreover, it is the first study to identify genes that affect fermentation performance under high-gravity conditions. The results are of interest to the beer and bioethanol industries, where the use of more-concentrated medium is economically advantageous.

Beer↗

PubMed1997

Influence of invertase activity and glycerol synthesis and retention on fermentation of media with a high sugar concentration by Saccharomyces cerevisiae.

In the past, the fermentation activity of Saccharomyces cerevisiae in substrates with a high concentration of sucrose (HSuc), such as sweet bread doughs, has been linked inversely to invertase activity of yeast strains. The present work defines the limits of the relationship between invertase activity and fermentation in hyperosmotic HSuc medium. Fourteen polyploid, wild-type strains of S. cerevisiae with different invertase levels gave a similar ranking of fermentation activity in HSuc and in medium in which glucose and fructose replaced sucrose (HGF medium). Thus, invertase is unlikely to be the most important determinant of fermentation in sweet doughs. Yeasts produce the compatible solute-osmoprotective compound glycerol when exposed to hyperosmotic environments. Under low sugar concentrations (and nonstressing osmotic pressure), there was no correlation between glycerol and fermentation activities. However, there was a strong correlation between the ability of yeasts to ferment in HSuc or HGF medium and their capacity to produce and retain glycerol intracellularly. There was also a strong correlation between intracellular glycerol and fermentation activity of yeasts in a medium in which the nonfermentable sugar alcohol sorbitol replaced most of the sugars (HSor), but the ability to produce and retain glycerol was greater when yeasts were incubated in HGF medium under the same osmotic pressure. The difference between the amounts of glycerol produced and retained in HSor and in HGF media varied with strains. This implies that high fermentable sugar concentrations cause physiological conditions that allow for enhanced glycerol production and retention, the degree of which is strain dependent. In conclusion, one important prerequisite for yeast strains to ferment media with high concentrations of sugar is the ability to synthesize glycerol and especially to retain it.

Carbohydrate Metabolism↗

PubMed2002

Yeast diversity and persistence in botrytis-affected wine fermentations.

Culture-dependent and -independent methods were used to examine the yeast diversity present in botrytis-affected ("botrytized") wine fermentations carried out at high ( approximately 30 degrees C) and ambient ( approximately 20 degrees C) temperatures. Fermentations at both temperatures possessed similar populations of Saccharomyces, Hanseniaspora, Pichia, Metschnikowia, Kluyveromyces, and Candida species. However, higher populations of non-Saccharomyces yeasts persisted in ambient-temperature fermentations, with Candida and, to a lesser extent, Kluyveromyces species remaining long after the fermentation was dominated by Saccharomyces. In general, denaturing gradient gel electrophoresis profiles of yeast ribosomal DNA or rRNA amplified from the fermentation samples correlated well with the plating data. The direct molecular methods also revealed a Hanseniaspora osmophila population not identified in the plating analysis. rRNA analysis also indicated a large population (>10(6) cells per ml) of a nonculturable Candida strain in the high-temperature fermentation. Monoculture analysis of the Candida isolate indicated an extreme fructophilic phenotype and correlated with an increased glucose/fructose ratio in fermentations containing higher populations of Candida. Analysis of wine fermentation microbial ecology by using both culture-dependent and -independent methods reveals the complexity of yeast interactions enriched during spontaneous fermentations.

Botrytis↗

PubMed2003

Bacteriophage ecology in commercial sauerkraut fermentations.

Knowledge of bacteriophage ecology in vegetable fermentations is essential for developing phage control strategies for consistent and high quality of fermented vegetable products. The ecology of phages infecting lactic acid bacteria (LAB) in commercial sauerkraut fermentations was investigated. Brine samples were taken from four commercial sauerkraut fermentation tanks over a 60- or 100-day period in 2000 and 2001. A total of 171 phage isolates, including at least 26 distinct phages, were obtained. In addition, 28 distinct host strains were isolated and identified as LAB by restriction analysis of the intergenic transcribed spacer region and 16S rRNA sequence analysis. These host strains included Leuconostoc, Weissella, and Lactobacillus species. It was found that there were two phage-host systems in the fermentations corresponding to the population shift from heterofermentative to homofermentative LAB between 3 and 7 days after the start of the fermentations. The data suggested that phages may play an important role in the microbial ecology and succession of LAB species in vegetable fermentations. Eight phage isolates, which were independently obtained two or more times, were further characterized. They belonged to the family Myoviridae or Siphoviridae and showed distinct host ranges and DNA fingerprints. Two of the phage isolates were found to be capable of infecting two Lactobacillus species. The results from this study demonstrated for the first time the complex phage ecology present in commercial sauerkraut fermentations, providing new insights into the bioprocess of vegetable fermentations.

Bacteriophages↗

PubMed1966

Multiplication and fermentation of Saccharomyces cerevisiae under carbon dioxide pressure in wine.

Conditions for rapid fermentation of sugar in wine under pressure were sought for use in continuous production of naturally fermented sparkling wine. Wine yeast growth and fermentation were measured under CO(2) pressure. The medium was white wine with added glucose. Pressure was very inhibitory to growth, especially at low pH or high alcohol concentration. Use of various strains of wine yeast, cultures of various ages, or cells adapted to wine did not give more rapid growth. Addition of nutrients increased growth, but under no conditions was growth rapid enough to bring about sufficiently rapid fermentation rates. Conditions for rapid fermentation were sought by use of high levels of cells as inocula. Fermentation rates in wine also were inhibited by pressure, and were dependent on pH and alcohol levels. Addition of nutrients did not increase the fermentation rate, but rapid fermentation rates were obtained, under pressure, by inoculation with high levels of cells adapted several weeks to the base wine. Thus, continuous sparkling-wine production might be practical with proper amounts of adapted cells used as inocula, or perhaps with reuse of the fermentation culture.

Carbon Dioxide↗

PubMed1974

Effect of dissolved oxygen, temperature, initial cell count, and sugar concentration on the viability of Saccharomyces cerevisiae in rapid fermentations.

By using 7 x 10(8) cells of Saccharomyces cerevisiae per ml with which 25 degrees Brix honey solutions were fermented to 9.5% (wt/vol; 12% vol/vol) ethanol in 2.5 to 3 h at 30 C, i.e., rapid fermentation, the death rate was found to be high, with only 2.1% of the yeast cells surviving at the end of 3 h under anaerobic conditions. As the dissolved oxygen in the medium was increased from 0 to 13 to 20 to 100% in rapid fermentations at 30 C, there was a progressive increase in the percentage of cells surviving. The ethanol production rate and total were not seriously affected by a dissolved oxygen concentration of 13%, but fermentation was retarded by 20% dissolved oxygen and still further decreased as the dissolved oxygen content reached 100%. When the fermentation temperature was decreased to 15 C (at 13% dissolved oxygen), the rate of fermentation decreased, and the fermentation time to 9.5% ethanol (wt/vol) increased to 6 h. It was found that the higher the temperature between 15 and 30 C, the greater the rate of death as initial cell counts were increased from 1.1 x 10(7) to 7.8 x 10(8) cells per ml. At the lowest level of inoculum, 1.1 x 10(7) cells per ml, there was actual multiplication, even at 30 C; however, the fermentation was no longer rapid. The addition of 15% sugar, initially followed after an hour by the remaining 10%, or addition of the sugar in increments of 2.5 or 5% yielded a better survival rate of yeast cells than when the fermentation was initiated with 25% sugar.

Aerobiosis↗

PubMed1989

Constancy of glucose and starch fermentations by two different human faecal microbial communities.

The fermentation of glucose and corn starch by faecal suspensions from two subjects was examined over a three and a half year period. The substrate specificity and products of the faecal fermentations of each subject were relatively stable during this period and were significantly different between subjects. The major soluble end products of fermentation of glucose or starch were acetate, propionate, and butyrate. Hydrogen temporarily accumulated and was subsequently used in fermentations by both subjects. Hydrogen was used without methane production in fermentations of subject 1, but was used for methane formation in fermentations of subject 2. Although the rates of glucose fermentation were similar between both subjects; subject 1 produced a significantly greater molar ratio of propionate than did subject 2. The rate of fermentation of starch by faecal suspensions from subject 1 was faster than that of subject 2. The molar ratio of butyrate was greater for starch fermentations by subject 2, while the molar ratio of propionate was greater with subject 1. Significant differences were found between subjects in molar ratios and concentration of acetate and propionate and concentrations of butyrate in faeces.

Acetates↗

PubMed2001

Preventive effects of Bifidobacterium- and Lactobacillus-fermented milk on the development of inflammatory bowel disease in senescence-accelerated mouse P1/Yit strain mice.

BACKGROUND/AIMS: We recently discovered inflammatory bowel disease (IBD) in the ileum and cecum of SAMP1/Yit strain mice under specific pathogen-free (SPF) conditions. To determine the effect of lactic acid bacteria (LAB - Bifidobacterium breve, Bifidobacterium bifidum and Lactobacillus acidophilus)-fermented milk on the prevention of IBD in SAMP1/Yit strain mice, we compared the disease severity on the intestinal inflammation among the group of mice fed saline, unfermented milk or LAB-fermented milk. METHODS: Three-week-old SAMP1/Yit strain mice (n = 72) were subdivided into three groups, that were fed saline, unfermented milk and LAB-fermented milk, respectively. The diets were orally administered daily via a gastric tube. When the mice reached 20 weeks of age, they were sacrificed and the IBD scores were compared among the three groups. RESULTS: Administration of the LAB-fermented milk to SAMP1/Yit strain mice reduced histological injury score, compared with those in saline-treated or unfermented milk-treated SAMP1/Yit strain mice. Ileal tissue weight and myeloperoxidase activity also reduced by treatment of LAB-fermented milk. Moreover, the tissue contents of immunoglobulins such as IgG1 and IgG2a were lower in the inflammatory regions in the SAMP1/Yit strain group fed LAB-fermented milk than that fed saline and unfermented milk. Cytokine-specific ELISA assays indicated the production of T-helper 1 cytokines such as interferon-gamma and tumor necrosis factor-alpha in the culture supernatants of MLN cells in the SAMP1/Yit strain group fed LAB-fermented milk was lower than those fed saline and unfermented milk. On the contrary, the production of interleukin-10 in MLN cells increased by prevention with LAB-fermented milk. CONCLUSION: LAB-fermented milk is beneficial for the treatment of murine IBD and this effect may be modulated through stabilization of the mucosal immunity by LAB.

Aging↗

PubMedDate not supplied

In vitro fermentation of high-amylose cornstarch by a mixed population of colonic bacteria.

BACKGROUND: Malabsorbed starch is probably the most important substrate for bacterial fermentation in the human large intestine. Fermentability of starch may depend on the composition of the colonic flora and its adaptation to the substrate supply. METHODS: Ten healthy volunteers were fed a controlled diet containing either 7.0 to 8.3 or 50.7 to 59.7 g/d of resistant starch (Hylon VII) for 4 weeks. At the end of each diet period, fecal starch concentrations were measured. Fecal samples were incubated in 48-hour batch cultures containing 10 g/L Hylon VII or digestible Lintner's starch. Bacterial breakdown of starch and short-chain fatty acid concentrations were measured at 0, 3, 6, 12, 24, and 48 hours. RESULTS: Fecal starch concentrations were higher during the Hylon VII period (35.7 +/- 16 vs 8.9 +/- 3.3 mg/g). Starch was fermented rapidly and completely in vitro in all but two subjects. Fermentability of resistant starch was comparable to that of digestible starch. No differences were found between the dietary periods. Fermentation of resistant starch produced higher rates of n-butyrate. Two subjects had substantially higher fecal starch concentrations. In vitro starch breakdown in these subjects was slow and incomplete. CONCLUSIONS: Fermentation of resistant starch by the colonic microflora was rapid and complete in 8 of 10 subjects. No adaptation of the fermentation capacity was observed after 4 weeks of dietary resistant starch supplementation. Fermentation of resistant starch increased the proportion of n-butyrate in vitro. In two subjects, fecal starch concentrations were substantially higher than in the other subjects and in vitro starch fermentation was slow and incomplete.

Adult↗

PubMed1995

In vitro fermentation of selected fibrous substrates by dog and cat fecal inoculum: influence of diet composition on substrate organic matter disappearance and short-chain fatty acid production.

Two in vitro fermentation experiments were conducted to evaluate the influence of source of dietary fiber fed to dogs and cats on fermentative activity of their fecal microflora. In Exp. 1, six English Pointer dogs were fed a diet containing either a non-fermentable fiber (Solka Floc) or a fermentable fiber (citrus pulp). A fecal sample from each dog was used as the inoculum source to determine in vitro OM disappearance (OMD) and short-chain fatty acid (SCFA) production from selected fibrous substrates. When data were pooled across substrates and fermentation times, a lower (P = .02) OMD (24.8 vs 29.4%) and a higher (P = .01; 3.8 vs 2.2) acetate to propionate ratio (A:P) occurred for the Solka Floc than for the citrus pulp diet. In Exp. 2, six short-hair cats were fed a diet containing no supplemental fiber (NF) or a diet containing beet pulp (BP). When data were pooled across substrates and fermentation times, NF resulted in a greater (P < .01) A:P than the BP diet (3.4 vs 1.5). The BP treatment resulted in a slightly higher (P = .07) OMD (42.0 vs 39.3%) and a higher (P = .07) propionate production (.74 vs .47 mmol/g of OM) than the NF diet. In summary, in vitro substrate OMD increased and A:P decreased when fecal inoculum from dogs and cats fed diets containing a supplemental source of fermentable fiber was used. In vitro fermentation of fibrous substrates by fecal microflora from dogs and cats increased with inclusion of fermentable fiber in the diet.

Animal Feed↗

PubMed1993

Tempeh: a mold-modified indigenous fermented food made from soybeans and/or cereal grains.

A variety of indigenous fermented foods exist today; however, tempeh has been one of the most widely accepted and researched mold-modified fermented products. Tempeh is a traditional fermented food made from soaked and cooked soybeans inoculated with a mold, usually of the genus Rhizopus. After fermentation has occurred, the soybeans are bound together into a compact cake by dense cottony mycelium. An important function of the mold in the fermentation process is the synthesis of enzymes, which hydrolyze soybean constituents and contribute to the development of a desirable texture, flavor, and aroma of the product. Enzymatic hydrolysis also may decrease or eliminate antinutritional constituents; consequently, the nutritional quality of the fermented product may be improved. Current technology and new scientific advancements have enabled researchers to examine specific strains of Rhizopus and new substrates such as cereal grains. Because Kansas produces numerous cereal grains, production of a fermented tempeh-like product using wheat, sorghum (milo), oats, rye, barley, corn, and triticale is a definite possibility for generating a Kansas Value-Added Product. In this study, several different tempeh-like products were produced using various cereal grains inoculated with Rhizopus oligosporus NRRL 2549 or R. oligosporus NRRL 2710. Grains used included hard red winter wheat, triticale, yellow sorghum (milo), and red sorghum (milo). The grain source as well as the strain of R. oligosporus used influenced the product's appearance, flavor, and patty integrity. Results showed that R. oligosporus NRRL 2549 produced more mycelium at a more rapid rate than did the R. oligosporus NRRL 2710 strain. The combination of red sorghum and R. oligosporus NRRL 2549 yielded a product with good patty texture, aroma, and appearance. Furthermore, the red sorghum fermented product was well suited for slicing. On the other hand, yellow sorghum inoculated with either R. oligosporus NRRL 2549 or R. oligosporus NRRL 2710 failed to produce an organoleptically suitable product. Triticale also was found to be an unacceptable substrate for the production of a tempeh-like product. Although the fermented wheat product had a desirable aroma and flavor, it lacked patty integrity and crumbled when sliced. Further research is needed to evaluate the economic significance and industrial applications of these tempeh-like products.

Edible Grain↗