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PubMed1997

Preservation of hatchery waste by lactic acid fermentation. 2. Large-scale fermentation and feeding trial to evaluate feeding value.

Two waste streams from a Leghorn hatchery were preserved and recycled by fermentation with a by-product carbohydrate and extrusion processing into new feed ingredients that were evaluated with broiler chickens. Cockerel chicks (CC) and a 60:40 ratio of CC:shell waste (CC:SW) were fermented in 189-L barrels for 21 d following grinding, then mixing with a liquid culture (0.2%) and carbohydrate source at 15 and 16.66%, respectively. At 2 wk, pH was 4.44 and 5.09 for the CC and CC:SW products compared with higher values of 6.54 and 6.98 for the raw ingredients at the onset. Negligible hydrogen sulfide and no ammonia gas were recorded during the fermentation period. At 21 d, the fermented CC and CC:SW were extruded, dried, and ground to meals containing CP and TMEn levels of 47.4%, 3,187 kcal/kg, and 33.1%, 2,696 kcal/kg, respectively. Broiler chickens were fed a control diet and the CC (5 and 10%) and CC:SW (2.5 and 5%) ingredient diets with corn and soybean meal for 6 wk to evaluate feeding value and carcass yield. Body weight, gain and feed conversion at 42 d for birds fed diets supplemented with CC or CC:SW at all levels were comparable to those of the control. Diets supplemented with hatchery by-product had no negative effect on carcass measurements except ready to cook carcass and wing yield, which were significantly greater for the 10% CC:SW birds than for the control. These data indicate that nutrient dense hatchery by-products can be preserved with fermentation up to 21 d and support broiler live performance and carcass yield as dietary ingredients equal to or better than a corn-soybean meal control.

Analysis of Variance↗
PubMed1999

Polyphasic study of the spatial distribution of microorganisms in Mexican pozol, a fermented maize dough, demonstrates the need for cultivation-independent methods to investigate traditional fermentations.

The distribution of microorganisms in pozol balls, a fermented maize dough, was investigated by a polyphasic approach in which we used both culture-dependent and culture-independent methods, including microbial enumeration, fermentation product analysis, quantification of microbial taxa with 16S rRNA-targeted oligonucleotide probes, determination of microbial fingerprints by denaturing gradient gel electrophoresis (DGGE), and 16S ribosomal DNA gene sequencing. Our results demonstrate that DGGE fingerprinting and rRNA quantification should allow workers to precisely and rapidly characterize the microbial assemblage in a spontaneous lactic acid fermented food. Lactic acid bacteria (LAB) accounted for 90 to 97% of the total active microflora; no streptococci were isolated, although members of the genus Streptococcus accounted for 25 to 50% of the microflora. Lactobacillus plantarum and Lactobacillus fermentum, together with members of the genera Leuconostoc and Weissella, were the other dominant organisms. The overall activity was more important at the periphery of a ball, where eucaryotes, enterobacteria, and bacterial exopolysacharide producers developed. Our results also showed that the metabolism of heterofermentative LAB was influenced in situ by the distribution of the LAB in the pozol ball, whereas homolactic fermentation was controlled primarily by sugar limitation. We propose that starch is first degraded by amylases from LAB and that the resulting sugars, together with the lactate produced, allow a secondary flora to develop in the presence of oxygen. Our results strongly suggest that cultivation-independent methods should be used to study traditional fermented foods.

Agriculture↗
PubMed1990

Effects of Aspergillus oryzae fermentation extract on fermentation of amino acids, bermudagrass and starch by mixed ruminal microorganisms in vitro.

The objective of this study was to examine the effects of Aspergillus oryzae fermentation extract (Amaferm) on the in vitro ruminal fermentation of coastal bermudagrass, soluble starch and amino acids. Mixed ruminal microorganisms were incubated in anaerobic media for either 24 h (Amaferm alone, soluble starch, amino acids) or 48 h (bermudagrass). Amaferm was added to the incubation bottles (n = 4) at concentrations of 0, .4 or 1.0 g/liter. When mixed ruminal microorganisms were incubated with only Amaferm, the 1.0 g/liter concentration increased the production of hydrogen (H2; P less than .001), methane (CH4; P less than .01), acetate (P less than .05), butyrate (P less than .01), total VFA (P less than .05) and NH3 (P less than .05). Addition of both levels of Amaferm to soluble-starch fermentations tended to enhance the production of H2 (P less than .11), CH4 (P less than .15), acetate (P less than .29) and total VFA (P less than .19); propionate production was increased (P less than .10) by 1.0 g/liter Amaferm, resulting in a decrease (P less than .05) in the acetate:propionate ratio. Fermentation of amino acids plus 1.0 g/liter Amaferm enhanced the production of acetate (P less than .05), propionate (P less than .05), valerate (P less than .01) and total VFA (P less than .10) and decreased the acetate:propionate ratio (P less than .05). In addition, NH3 production tended (P less than .19) to increase with both levels of Amaferm. When bermudagrass was the substrate, few changes in fermentation products were observed with Amaferm treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1991

Fermentation to short-chain fatty acids and lactate in human faecal batch cultures. Intra- and inter-individual variations versus variations caused by changes in fermented saccharides.

The fermentation to short-chain fatty acids, lactate, and ammonia from several non-starch polysaccharides, glucose, and albumin was investigated in 16.6% faecal homogenates. Increasing concentrations (0-30 mg/ml) of glucose, wheat bran, pectin, ispaghula, cellulose, or albumin incubated for 24 h in homogenates pooled from three individuals increased short-chain fatty acid production linearly. Amounts and ratios of short-chain fatty acids formed were highly dependent on the type of substrate fermented. Fermentable saccharides increased ammonia assimilation, in contrast to the metabolic inert cellulose. Nine faecal homogenates sampled from three individuals at three occasions were incubated for 6 and 24 h. The production of total short-chain fatty acids, acetate, propionate, and butyrate and the accumulation of D- and L-lactate changed considerably in relation to the type of substrate added (cellulose, ispaghula, wheat bran, pectin, gum arabic, and glucose; p less than 10(-4)-10(-7). In contrast, there were no significant (p greater than 0.05) differences in organic acid formation between the nine homogenates, and the intra- and inter-individual variations were of the same magnitude. Variations in fermentation, when measured as organic acid formation, were therefore related to the type of substrate fermented rather than the individual tested.

Adult↗
PubMed2004

Short communication: effect of carbohydrate fermentation rate on estimates of mass fermented and milk response.

Current prediction equations were used to evaluate the effects of rates of fermentation of fiber or starch in individual feeds on amounts of carbohydrate fermented ruminally and milk yield responses. The small predicted increases in carbohydrate fermented and milk response associated with doubling the rates of fermentation suggest that current prediction equations are relatively insensitive to changes in rate of fermentation.

Animals↗
PubMed2005

Influence of starter culture on flavor and headspace volatile profiles of fermented whey and whey produced from fermented milk.

Rennet whey and skim milk were compared as media for fermentation by commercial cheese, yogurt, and probiotic starter cultures. Effect of culture, medium, and their interaction on flavor was assessed and compared by sensory descriptive analysis and headspace volatile analysis by proton transfer reaction-mass spectrometry. In general, the aroma of fermented whey was similar to that of whey separated from fermented milk, indicating a favorable possibility of substituting milk with whey in the manufacture of fermented milk-like beverages. Starter culture significantly affected most sensory characteristics of the products. Key volatile compounds for the characteristic flavor of yogurt, such as acetaldehyde and diacetyl, were not significantly affected by medium when fermented with the yogurt culture, and reached similar levels in both systems. Volatile analysis results were consistent with the results of the sensory evaluation, indicating the high reliability of proton transfer reaction-mass spectrometry in detecting important volatile compounds for aroma. Integration of this sensory and chemical information allows a better understanding of how flavor and related compounds are affected by ingredients or processing, which may be useful for the development of value-added whey products.

Acetaldehyde↗
PubMed1969

Fermentation patterns of poorly fermenting cabbage hybrids.

Thirteen varieties of cabbage, including five commonly used commercial varieties and eight newly developed hybrids, were analyzed for their ability to undergo lactic acid fermentations. The rates of fermentation, total quantities of acids produced, and chemical analyses indicate that 11 of the 13 selections could support adequate fermentation at any of the three stages of maturation. However, two varieties G27 x G51 (105) and G60 x W-1 (106), harvested during the earlier phases of the 1967 and 1968 growing seasons, failed to undergo proper fermentations and consistently resulted in producing putrid products. These hybrids when harvested at the late stage of maturation were capable of producing total titratable acidities comparable to the acceptable varieties. However the resulting sauerkrauts were judged to be of poor quality. The inability of these varieties to support adequate fermentations may be due to growth inhibitory substances or the lack of inherent maturation-dependent growth factor(s) essential for the growth of lactic acid bacteria.

Journal Article↗
PubMed1990

Fermentation of pearl millet flour with yeasts and lactobacilli: in vitro digestibility and utilisation of fermented flour for weaning mixtures.

Single as well as mixed culture fermentation by yeasts (S. diastaticus; S. cerevistiae) and lactobacilli (L. brevis; L. fermentum) at 30 degrees C for 72 h improved the starch and protein digestibility (in vitro) of pearl millet flour significantly. The flour fermented by Saccharomyces diastaticus, a starch hydrolysing yeast, had the highest starch digestibility whereas fermentation by Saccharomyces cerevisiae enhanced the in vitro protein digestibility of the flour significantly. Weaning mixtures prepared from the fermented flour were also found to be organoleptically acceptable.

Dietary Carbohydrates↗
PubMedDate not supplied

Growth of fermentative and non-fermentative yeasts in natural yoghurt, stored in polystyrene cartons.

Permeation of oxygen through polystyrene packaging is a factor in the growth of yeasts in natural yoghurt. Diffusion of oxygen through the packaging material can permit the growth of non-fermentative yeasts in yoghurt stored at refrigeration temperatures. Yarrowia lipolytica, a non-fermentative yeasts which does not utilize lactose was isolated from yoghurt. The growth in natural yoghurt of Yarrowia lipolytica and the lactose-fermenting yeast Kluyveromyces marxianus was investigated. Both yeasts grew in yoghurt with reduced fat content. Storage of yoghurt in an anaerobic atmosphere eliminated growth of Yarrowia lipolytica but permitted fermentative growth of Kluyveromyces marxianus.

Fermentation↗
PubMed1998

Production of fermented milk using a malty compound-producing strain of Lactococcus lactis subsp. lactis biovar. diacetylactis, isolated from Zimbabwean naturally fermented milk.

Malty compound-producing Lactococcus lactis subsp. lactis biovar. diacetylactis strain INF-DM1, originally isolated from naturally fermented milk in Zimbabwe was used to prepare fermented milk from ordinary milk, milk enriched with 2.5% (w/v) skimmed milk powder and by 2.5% (w/v) increase in dry matter by ultrafiltration. Inoculated milk was incubated at 22, 30 and 37 degrees C. Analyses were made after 0, 9, 18 and 24 h incubation and also after 24 h incubation followed by storage for one week at 4 degrees C. Samples were analysed for volatile compounds including malty compounds and for organic acids, pH and log cfu/g. All samples were also judged for sensory attributes. Products made from enriched milks showed increased viscosity which was most marked in ultrafiltrated milk incubated at 30 and 37 degrees C. The levels of certain compounds (lactic acid, citrate and diacetyl) were significantly affected by milk type. Incubation temperature had a significant effect on starter growth rate and the rate of production and amount of the malty compounds, lactate, diacetyl, ethanol, acetoin and acetaldehyde. 3-Methyl butanal concentrations were above the taste threshold level of 0.06 ppm in almost all products, including stored products. Although initial growth rate was fastest at 37 degrees C, an uncoupling of acid production and growth was observed after 9 h incubation, suggesting that this is above the optimum temperature for this strain. In addition, products incubated at 37 degrees C showed a tendency to whey separation, indicating that this temperature is also too high to give optimum product quality. All products attained good scores in sensory analysis provided that fermentation was complete. Variation in the levels of malty compounds during the fermentation had no significant effect on the sensory score for total flavour.

Acetaldehyde↗
PubMedDate not supplied

Human chymotrypsinogen B production with Pichia pastoris by integrated development of fermentation and downstream processing. Part 1. Fermentation.

Based on an integrated approach of genetic engineering, fermentation process development, and downstream processing, a fermentative chymotrypsinogen B production process using recombinant Pichia pastoris is presented. Making use of the P. pastoris AOX1-promotor, the demand for methanol as the single carbon source as well as an inducer of protein secretion enforced the use of an optimized feeding strategy by help of on-line analysis and an advanced controller algorithm. By using an experimental system of six parallel sparged column bioreactors, proteolytic product degradation could be minimized while also optimizing starting conditions for the following downstream processing. This optimization of process conditions resulted in the production of authentic chymotrypsinogen at a final concentration level of 480 mg.L(-)(1) in the whole broth and a biomass concentration of 150 g.L(-)(1) cell dry weight, thus comprising a space-time yield of 5.2 mg.L(-)(1).h(-)(1). Alternatively to the high cell density fermentation approach, a continuous fermentation process was developed to study the effects of reduced cell density toward oxygen demand, cooling energy, and biomass separation. This development led to a process with a highly increased space-time yield of 25 mg.L(-)(1).h(-)(1) while reducing the cell dry weight concentration from 150 g.L(-)(1) in fed-batch to 65 g.L(-)(1) in continuous cultivation.

Chymotrypsinogen↗
PubMed2001

Application of multistage continuous fermentation for production of fuel alcohol by very-high-gravity fermentation technology.

A fermentation system to test the merging of very-high-gravity (VHG) and multistage continuous culture fermentation (MCCF) technologies was constructed and evaluated for fuel ethanol production. Simulated mashes ranging from 15% to 32% w/v glucose were fermented by Saccharomyces cerevisiae and the dilution rates were adjusted for each glucose concentration to provide an effluent containing less than 0.3% w/v glucose (greater than 99% consumption of glucose). The MCCF can be operated with glucose concentrations up to 32% w/v, which indicates that the system can successfully operate under VHG conditions. With 32% w/v glucose in the medium reservoir, a maximum of 16.73% v/v ethanol was produced in the MCCF. The introduction of VHG fermentation into continuous culture technology allows an improvement in ethanol productivity while producing ethanol continuously. In comparing the viability of yeast by methylene blue and plate count procedures, the results in this work indicate that the methylene blue procedure may overestimate the proportion of dead cells in the population. Ethanol productivity (Yps) increased from the first to the last fermentor in the sequence at all glucose concentrations used. This indicated that ethanol is more effectively produced in later fermentors in the MCCF, and that the notion of a constant Yps is not a valid assumption for use in mathematical modeling of MCCFs.

Biomass↗
PubMed1999

Culture-independent quantification of physiologically-active microbial groups in fermented foods using rRNA-targeted oligonucleotide probes: application to pozol, a Mexican lactic acid fermented maize dough.

Nine phylogenetic oligonucleotide probes were used to describe at the genus level the microbial community responsible for the spontaneous fermentation of maize, leading to the production of Mexican pozol. Ribosomal RNAs of specific groups and genera, in particular, lactic acid bacteria, were quantified using a culture-independent approach. In the early stage of the fermentation, Lactococcus and Leuconostoc appeared to be the dominant genera. A contrario, these represented minor genera at the end of the fermentation when Lactobacillus dominated the process. In addition, eukaryotes seemed to play a significant role throughout the fermentation and enterobacteria could be detected by this method.

Enterobacteriaceae↗
PubMed1995

The antimicrobial activity of lactic acid bacteria from fermented maize (kenkey) and their interactions during fermentation.

A total of 241 lactic acid bacteria belonging to Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus fermentum/reuteri and Lactobacillus brevis from various processing stages of maize dough fermentation were investigated. Results indicated that each processing stage has its own microenvironment with strong antimicrobial activity. About half of the Lact. plantarum and practically all of the Lact. fermentum/reuteri investigated were shown to inhibit other Gram-positive and Gram-negative bacteria, explaining the elimination of these organisms during the initial processing stages. Further, widespread microbial interactions amounting to 85% to 18% of all combinations tested were demonstrated amongst lactic acid bacteria within the various processing stages, i.e. raw material, steeping, 0 h and 48 h of fermentation, explaining the microbial succession taking place amongst lactic acid bacteria during fermentation. The antimicrobial effect was explained by the combined effect of acids, compounds sensitive to proteolytic enzymes and other compounds with antimicrobial activity with the acid production being the most important factor. The pattern of antimicrobial factors was not species-specific and the safety and storage stability of fermented maize seem to depend on a mixed population of lactic acid bacteria with different types of antimicrobial characteristics. This means that introduction of pure cultures as starters may impose a risk to the product.

Anti-Bacterial Agents↗
PubMed2006

Isolation and characterization of lactic acid bacteria from dochi (fermented black beans), a traditional fermented food in Taiwan.

AIMS: To isolate, characterize and identify lactic acid bacteria (LAB) in dochi (fermented black beans), a traditional fermented food in Taiwan. METHODS AND RESULTS: A total of 30 samples were collected from three different dochi producers and analysed after different periods of storage. Fifty-two cultures of LAB were isolated from dochi samples and the isolates were divided into classes by phenotype and then into groups by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Phenotypic and biochemical characteristics identified six different bacterial groups (A-F) and showed that the majority of the isolates were homofermentative LAB. Enterococcus faecium was the most abundant of the dochi-isolated LAB. All isolated LAB were able to grow in MRS broth containing 6% NaCl, but only Enterococcus, Pediococcus and Tetragenococcus species could grow in MRS broth containing 10% NaCl. Furthermore, antibacterial activities of isolates were determined, and four isolates showed inhibitory activities against the indicator strain Lactobacillus sakei JCM 1157(T). CONCLUSIONS: These results suggest that Ent. faecium is the main LAB present during the fermentation of dochi. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report describing the distribution and varieties of LAB that exist in the dochi fermentation process.

Antibiosis↗
PubMed1976

One-tube oxidation-fermentation methods: limitations posed by atypical fermentative reactions.

Atypical fermentation in the two-tube method of Hugh and Leifson (1953), whereby acid was produced in the sealed tube but not in the open tube, was determined to be the result of a preferential metabolism of peptone over the reactant carbohydrate. These atypical fermentations are only partially detected by one-tube oxidation-fermentation methods, and as such they constitute a source of limitation to the routine use of these abbreviated techniques for oxidative-fermentation determinations.

Aerobiosis↗
PubMed2002

Increasing fermentation efficiency at high sugar concentrations by supplementing an additional source of nitrogen during the exponential phase of the tequila fermentation process.

In the tequila industry, fermentation is traditionally achieved at sugar concentrations ranging from 50 to 100 g x L(-1). In this work, the behaviour of the Saccharomyces cerevisiae yeast (isolated from the juices of the Agave tequilana Weber blue variety) during the agave juice fermentation is compared at different sugar concentrations to determine if it is feasible for the industry to run fermentation at higher sugar concentrations. Fermentation efficiency is shown to be higher (above 90%) at a high concentration of initial sugar (170 g x L(-1)) when an additional source of nitrogen (a mixture of amino acids and ammonium sulphate, different than a grape must nitrogen composition) is added during the exponential growth phase.

Alcoholic Beverages↗
PubMed2000

The cause of "acid-crash" and "acidogenic fermentations" during the batch acetone-butanol-ethanol (ABE-) fermentation process.

Experiments were performed to determine the cause of "acid crash", a phenomenon which occasionally occurs in pH-uncontrolled batch fermentations resulting in premature cessation of ABE (acetone butanol) production. The results indicate that "acid crash" occurs when the concentration of undissociated acids in the broth exceeds 57 - 60 mmol/l. Prevention can be achieved by introducing some limited pH control to minimize the concentration of undissociated acids or by slowing the metabolic rate, and thus the rate of acid production, by, for example, lowering the fermentation temperature. "Acidogenic fermentations", which occur when batch fermentations are performed at pH values close to neutrality, are due to rapid production of acids followed by inhibition of solventogenesis when the total acid concentration reaches 240 - 250 mmol/l. Solventogenesis can be achieved at these pH values by lowering the glucose uptake rate / acid production rate by use of e.g. elevated glucose or lowered yeast extract concentrations in the growth medium.

Acetone↗