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PubMed2005

The use of a biofilter for reducing off-gas odour from an industrial fermentation process.

This study evaluated the performance of a lab-scale, closed bed biofilter for the removal of odour in off-gas released from an industrial fermentation facility. This off-gas was emitted from the facility periodically after the sterilization of fermentation medium. The lab scale biofilter was operated for over two months, totalling 30 medium sterilizations. The biofilter was subjected to a shock odour load for each sterilization cycle and to two airflow conditions: the fermentation off-gas and compressed room air, which was cooler and drier than the fermentation off-gas. The biofilter was effective in removing odour under shock loading and variable operating conditions (temperature and relative humidity). An odour reduction rate of 72% was achieved immediately after medium sterilization when odour levels were highest (32 800 OU m(-3)). The filter had an odour removal efficiency of 61% and 67% for 24 h and 50 h after sterilization, respectively.

Air Movements↗
PubMed1982

Legume-based fermented foods: their preparation and nutritional quality.

Legume-based fermented foods are very popular in the Southeast Asia, the Near East, and parts of Africa. They form an appreciable part of daily diet of people as a main source of protein, calories, and certain vitamins. Preparation of legume-based fermented foods has remained to some extent an art, and their nutritional quality has been of interest to both professionals and layman. The fermentation process helps not only in improving the organoleptic quality of legumes but also enhances nutritional quality. This review examines the production of various legume-based fermented foods and critically assesses their nutritional quality.

Chromatography, High Pressure Liquid↗
PubMed2000

Dietary carbohydrates affect caecal fermentation and modify nitrogen excretion patterns in rats. I. Studies with protein-free diets.

In a two-factorial experiment on 96 young male rats, the effects of substituting 10% raw potato starch (PS), pectins (PEC), or cellulose (CEL) for corn starch (CS) were studied using an unsupplemented protein-free (PF) diet or a PF diet supplemented either with DL-methionine or urea. The pH and the short chain fatty acids (SCFA) content in caecal digesta, as well as caecal digesta and tissue weights were determined and used as the criteria of caecal fermentation intensity. Blood urea level, amount of N excreted via faeces and urine, DAPA content, and amino acid composition of faecal protein were analyzed as indices of protein metabolism. A 10-day adaptation period to the carbohydrates fed with the casein diet preceded the experimental period of feeding the respective carbohydrates with protein-free diets. Dietary carbohydrates significantly influenced total and individual SCFA content in caecal digesta, as well as other parameters related to the intensity of fermentation. Potato starch and pectins were more intensively fermented than cellulose. Supplementation of the PF diet with methionine and urea affected only caecal isobutyric and valeric acid content in a way dependent on the carbohydrates present in the diet. Carbohydrates significantly altered the routes of N excretion. Faecal excretion was increased by all carbohydrates studied compared to corn starch, pectins had the most marked effect. Urinary excretion was significantly increased by cellulose (as compared with the PEC and PS groups) and decreased by pectins as compared with all other groups. There was an interaction between the effects of carbohydrates and type of protein-free diet on faecal and urinary excretion. The sum of amino acids in faecal protein was the lowest on the PEC diet, but the amino acid composition expressed as a per cent of total amino acid content was similar in all groups. It can be concluded that dietary carbohydrates alter the excretion patterns of endogenous nitrogen in rats in different ways and that this effect is related to the intensity of their fermentation in the hind gut.

Animals↗
PubMed2000

Dietary carbohydrates affect caecal fermentation and modify nitrogen excretion patterns in rats. II. Studies with diets differing in protein quality.

In 2 two-factorial experiments, each conducted on 80 growing male rats, the effects of substituting 10% raw potato starch (PS), pectins (PEC), or cellulose (CEL) for wheat starch (WS) and the addition of tannic acid to WS (WSTA) were studied using diets differing in protein quality. Casein unsupplemented or supplemented with DL-methionine and gluten unsupplemented or supplemented with lysine, methionine and tryptophan were used as protein sources in Experiment 1 and 2, respectively. Parameters indicative of caecal fermentation intensity (pH, acetic, propionic and butyric acid contents, digesta and tissue weight) and of protein metabolism (urea blood concentration, faecal and urinary nitrogen excretion) were determined. Ten-day balance experiments were preceded by a 10-day adaption period to respective carbohydrates given in a diet containing balanced protein. In both experiments the type of carbohydrates affected the caecal concentration of individual and total SCFA and other parameters of fermentation intensity. Pectins and potato starch were fermented more intensively than cellulose. Faecal N excretion was increased by all carbohydrates substituted for cereal starch, and by tannic acid. Urinary excretion was greater on CEL than on PEC and WSTA containing casein and on other diets containing gluten. In both experiments urinary N excretion was the lowest on PEC diets. Protein quality had the greatest effect on apparent biological value and net protein utilization but all indices of protein utilization were also affected by carbohydrates. It is concluded that not only the amount of N excreted in faeces but also in urine is affected by the type and fermentability of carbohydrates.

Animal Feed↗
PubMed2006

Effect of different types of fibre supplemented with sunflower oil on ruminal fermentation and production of conjugated linoleic acids in vitro.

An in vitro study was conducted to determine the effect of different types of fibre supplemented with sunflower oil on ruminal fermentation and formation of conjugated linoleic acids (CLA) by mixed ruminal microorganisms. Cell wall components extracted from wheat straw (representing lignified fibre), soybean hulls (representing easily digestible fibre), and purified cellulose were used as substrates. Sunflower oil was supplemented at the same level for all three types of fibre. After 24 h of incubation, ruminal fermentation parameters (including 24 h gas production, pH value, concentration of ammonia nitrogen and volatile fatty acids) and the concentration of long chain fatty acids in the culture fluid were determined. Results showed that the type of fibre influenced ruminal fermentation traits and the biohydrogenation of unsaturated C18 fatty acids in vitro. Composition of LCFA and profile of CLA were altered by the fibre type. Compared to the digestible fibre and purified cellulose, lignified fibre significantly increased the production of cis-9, trans-11 CLA and total CLA (sum of cis-9, trans-11 CLA, trans-10, cis-12 CLA, trans-9, trans-11 CLA, and cis-9, cis-11 CLA) by ruminal microorganisms. It was concluded that ruminal fermentation and production of CLA can be affected by the type of dietary fibre.

Animal Feed↗
PubMed1993

Influence of Rhaponticum carthamoides Wild on the growth of ruminal bacteria in vitro and on fermentation in an artificial rumen (Rusitec).

The fermentation of a basal diet composed of hay and barley (80:20%) was compared with fermentation of three rations in which 5 and 10% of hay and 10% of basal diet were replaced with the above-ground part of Rhaponticum carthamoides Wild in an artificial rumen (Rusitec). Results of 14 days experiments indicated that the digestibility of dry matter, organic matter, detergent fibre, production of CO2 and methane, NH3-N in effluent and total and individual VFA (mmol/day) were not affected in the process of fermentation of experimental diets in comparison with the basal diet. Addition of Rhaponticum carthamoides did not modify the production, utilization and recovery of metabolic hydrogen, glucose utilization, ATP production, YATP and effectiveness of microbial biomass synthesis expressed in g of microbial N/kg of organic fermented biomass. Water extracts of Rhaponticum carthamoides had no influence on growth parameters of a mixed culture of rumen bacteria. Overall results of this experiment indicated that the above-ground part of Rhaponticum carthomoides fully replaced the 5 and 10% portions of hay or 10% portion of the whole diet.

Ammonia↗
PubMed1999

[Investigations on the fermentation quality of silage from low-nitrate green forage].

In 3-year-experiments green forage from Dactylis glomerata and Festuca species, produced by differentiated cutting frequencies, was ensiled under laboratory conditions. The forage was almost without nitrate. Because of the higher content of water-soluble carbohydrates the fermentability coefficients of Festuca species were above of Dactylis glomerata. The fermentability coefficients of both plant species were inferior in the second and third cut, even if the first cut was delayed until July. Despite of similar fermentability coefficients of the two plant species silages contained different amounts of lactic and butyric acid. The portion of lactic acid amounted to 52 to 57% and 60 to 73% of total acids, the proportion of butyric acid 30 to 35% and 18 to 25% for Dactylis glomerata and Festuca species, respectively. According to the high fermentability coefficients silages free of butyric acid would be expected, however, by both species butyric acid always was formed, in some cases at high concentrations. In the contrary the amounts of ammonia, acetic acid and alcohol as well as the pH-value were almost extremely low. It can be concluded that the quality of silages produced of green forages with low nitrate cannot be assessed adequately by the current evaluation key.

Acetic Acid↗
PubMed2004

Liquid state bioconversion of sewage treatment plant sludge in batch fermenter and shake flask.

A study on liquid state bioconversion of sewage treatment plant (STP) sludge was assisted to evaluate the performance of batch fermenter compared to shake flask in a laboratory. Bioconversion of STP sludge was highly influenced by the mixed fungal culture of Penicillium corylophilum and Aspergillus niger after 4 days of treatment. The results showed that about 24.9 g kg(-1) dry sludge cake (DSC) was produced with enrichment of fungal biomass protein in fermenter while 20.1 g kg(-1) in shake flask after 4 days of fungal treatment. The effective biodegradation of STP sludge was recorded in both fermenter and shake flask experiment compared to control (uninnoculated sample). The results presented in this study revealed that the overall performance of fermenter in terms of sludge cake (biosolids) accumulation and biodegradation of STP sludge was higher than the shake flask.

Aspergillus niger↗
PubMed1975

Effects of betel nut and fermented fish on the thiamin status of northeastern Thais.

Thiamin deficiency could result either from inadequate intake of thiamin or consumption of food containing antithiamin factors. Dietary surveys conducted in northeastern Thailand indicated that both thiamin and caloric intake of subjects under studies were sufficient. In Thailand, correlation exists between the consumption of food containing antithiamin factors and the prevalence of thiamin deficiency. Betel nuts and raw fermented fish possess antithiamin activity. Abstention from both betel nut chewing and raw fermented fish consumption resulted in a significant reduction of thiamin pyrophosphate effect. The thiamin pyrophosphate effect again increased significantly when the subjects resume their chewing habits. Cooking of fermented fish destroyed thiaminase, resulted in a significant decrease of thiamin pyrophosphate effect of the subjects. Thiamin supplementation (10 mg/day) could further reduce their thiamin pyrophosphate effect. This amount of thiamin could counteract the effect of raw fermented fish consumption but was not sufficient to neutralize the effect of betel nut chewing.

Adolescent↗
PubMed1988

Fermentation of oat fiber in the rat intestinal tract: a study of different cellular areas.

Intestinal fermentation of dietary fiber from oat husk, bran, and white flour and a commercial oat bran was investigated through balance experiments in rats. Both solubility and monomeric composition of the fiber differed widely. Fiber from husk was only 0.5% soluble and nearly completely resistant to fermentation whereas fiber from bran (38% soluble) and white flour (24% soluble) was more fermentable (62% and 55% of the intake, respectively). Fiber from commercial bran (37% soluble) was most extensively fermented; only 19% of the fiber could be detected in feces. The fecal dry weight with the husk in the diet was significantly (p less than 0.001) higher than that for the other preparations. Most of the fecal dry weight increment for husk (approximately 95%) could be accounted for as fiber whereas only 45-65% of the increment was undergraded fiber for the other preparations. An additional 20-30% could be explained by protein and approximately 15% by fat with these preparations.

Animals↗
PubMed1998

Production rate of acetate during colonic fermentation of lactulose: a stable-isotope study in humans.

BACKGROUND: Breath tests are currently used to qualitatively assess colonic fermentation; no quantitative estimations are available for healthy subjects. OBJECTIVE: This study describes a stable-isotope-dilution method to measure acetate production quantitatively from colonic bacterial fermentation. DESIGN: Six volunteers received a primed, constant, intravenous infusion of [1-13C]acetate at a rate of 1.01 +/- 0.04 micromol x kg(-1) x min(-1) for 7 h. They ingested 20 g pure lactulose after 1 h of the tracer infusion. Expired air and arterialized venous blood were sampled every 15 min. RESULTS: Before lactulose intake, the breath-hydrogen concentration was 7 +/- 2 ppm and the plasma acetate concentration and isotopic enrichment were 141 +/- 14 micromol/L and 14.8 +/- 1.4 moles percent excess, respectively. Whole-body acetate turnover was 6.0 +/- 0.7 micromol x kg(-1) x min(-1). After lactulose ingestion, maximum breath hydrogen and acetate concentrations reached 63 +/- 15 ppm (P = 0.004) and 313 +/- 25 micromol/L (P = 0.002), respectively, whereas [13C]acetate enrichment decreased to 9.9 +/- 1.3 moles percent excess (P = 0.03). Whole-body acetate turnover increased to 9.8 +/- 1.5 micromol x kg(-1) x min(-1) and later decreased almost to baseline values. Colonic lactulose fermentation yielded 140 +/- 12 mmol acetate over 6 h, representing 86% of the production based on stoichiometric equations. CONCLUSION: This new method provides a quantitative estimate of colonic carbohydrate fermentation via evaluation of acetate production.

Acetates↗
PubMed2002

Effects of high-resistant-starch banana flour (RS(2)) on in vitro fermentation and the small-bowel excretion of energy, nutrients, and sterols: an ileostomy study.

BACKGROUND: Resistant starch (RS) has attracted interest because of its effects in the colon and implications for health. Knowledge of how RS influences small-intestinal absorption of nutrients, sterol metabolism, and colonic fermentation is sparse. OBJECTIVES: The objectives of this study were to measure the effect of RS(2), a type of RS in banana flour, on the ileal excretion of energy, nutrients, and sterols, and to compare in vivo measurement of RS in the ileostomy model with previously published intubation data. In addition, we sought to estimate a fermentation pattern by using ileal effluents for in vitro fermentation. DESIGN: The present study was divided into 2 parts. Study A involved 10 ileostomy subjects who were given a controlled diet with the addition of 30 g raw green banana flour (RBF)/d, which contains RS(2), or cooked green banana flour (CBF)/d in random order. Study B involved 7 ileostomy subjects who were given a plant-polysaccharide-free diet with the addition of 30 g RBF/d. RESULTS: In study A, the dry weight of the ileostomy effluents and the ileal excretion of energy, iron, and chenodeoxycholic acid, but not total sterols, were higher after the addition of RBF than of CBF to the diet. In vitro fermentation of the ileal effluents obtained after the addition of RBF to the diet showed higher concentrations of acetate and butyrate. In study B, the ileal excretion of starch was lower than the amount calculated from earlier studies by use of the intubation technique. CONCLUSIONS: The addition of RBF containing RS(2) to the diet of ileostomy subjects did not interfere with small-bowel absorption of nutrients or total sterols, except for a small increase in iron excretion. The ileostomy model seems to give reliable results for in vivo measurement of RS.

Adult↗
PubMed1983

Colonic function and fermentation in men consuming high fiber diets.

The relationships between fermentation in the gut and colonic function were studied by using data derived from a human metabolic study. Five healthy men were fed diets that were fiber-free or contained cellulose, xylan, pectin or corn bran. Fermentation was assessed by measuring the excretion of flatus gas, volatile fatty acids (VFA) in feces and fecal pH. Colonic function was assessed by measuring transit time, fecal frequency, fecal output and fecal composition. Fibers that were only marginally fermented included cellulose and corn bran, and these fibers caused large fecal output, frequent defecations and prolonged the residence time of digesta in the gut; feces contained high levels of neutral detergent fiber (NDF); neither diet influenced fecal pH nor flatus gas excretion; and only corn bran increased VFA excretion in feces. Fibers that were mostly fermented in the gut included xylan and pectin, and these fibers did not influence fecal frequency or fecal output, but they did decrease transit time; both diets caused high levels of flatus gas to be excreted; pectin caused higher VFA excretion in feces and lower fecal pH. The excretion of VFA in feces was highly correlated with total fecal output, and high levels of VFA were associated with low flatus gas excretion. Mutagenic activity in feces was negligible for all subjects on all diets as measured by the fluctuation test.

Adult↗
PubMed1989

Effects of feeding fermentable carbohydrates on the cecal concentrations of minerals and their fluxes between the cecum and blood plasma in the rat.

This study was conducted to determine in rats to what extent fermentable carbohydrates alter the mineral composition of cecal contents and the absorption of the major cations. The carbohydrates studied were as follows: an oligosaccharide (lactulose, 10%); a soluble fiber (pectin, 10%); and an amylose-rich starch, incompletely broken down in the small intestine (amylomaize starch, 25 or 50%). All of these carbohydrates elicited a marked enlargement of the cecum, a drop of cecal pH and an increase in the volatile fatty acids (VFA) pool. With the lactulose diet, the VFA concentration was the lowest, whereas VFA absorption was similar to that observed with the 10% pectin or 25% amylomaize diets. From comparisons between germfree and conventional rats adapted to a fiber-free diet, it appears that VFA are required as counter anions to maintain high concentrations of cations, especially sodium. In conventional rats fed fermentable carbohydrates, sodium concentration in the cecal fluid was approximately 80 mM, except with the lactulose diet (49.5 mM), due to osmotic effects of lactulose. There was, compared to the fiber-free diet, an increase in the cecal concentrations of potassium, calcium and phosphate, but not of magnesium; nevertheless, the cecal pool of all of these minerals was considerably increased. Potassium absorption was increased by fermentable carbohydrates in the cecum, which also appears to be a major site of magnesium and calcium absorption. Thus, fermentable carbohydrates shift aborally the absorption of the major cations, and this point is especially interesting in regard to calcium, since an enhanced supply of calcium in the large bowel has been invoked for fiber effects on colonic carcinogenesis.

Animals↗
PubMed1991

High propionic acid fermentations and mineral accumulation in the cecum of rats adapted to different levels of inulin.

The digestive and metabolic effects of inulin (from chicory) were studied in rats adapted to semipurified diets containing 0, 5, 10 or 20% inulin (wt/wt). Moderate levels of inulin (5-10%) did not significantly affect food intake or body weight gain. Dietary inulin resulted in considerably greater cecal fermentation and a significantly greater intraluminal concentration of propionate (peaking at 58.4 mmol/L). A lower concentration of acetate (42.6 mmol/L) was observed in rats fed 20% inulin. Lactic fermentations were observed in rats fed the 10 or 20% inulin diets. The cecal pool of volatile fatty acids tended to reach a plateau in rats fed diets containing more than 10% inulin (up to 600-700 mumol), but volatile fatty acid absorption was a slightly hyperbolic function of the dietary inulin level. Butyrate absorption was proportionally lower than that of propionate. Inulin-containing diets induced an enlargement of the cecal pool of calcium, phosphate and (to a lesser extent) magnesium. There was also an enhanced absorption of these divalent cations. The cecal pool of bile acids was greater in rats fed inulin, and this oligosaccharide displayed a slight hypocholesterolemic effect, even in rats fed the 5% inulin diet. However, plasma triglycerides were depressed only in rats fed the 20% inulin diet. In conclusion, inulin seems very effective in promoting propionic fermentation and in enhancing the calcium content of the large intestine. However, high levels of inulin (greater than 10%) may affect growth in rats and lead to acidic (pH 5.65) cecal fermentation.

Adaptation, Physiological↗
PubMed1993

Viscosity and fermentability as attributes of dietary fiber responsible for the hypocholesterolemic effect in hamsters.

The attribute(s) of soluble dietary fibers responsible for cholesterol lowering is currently uncertain. A series of experiments were conducted in which viscosity and fermentability was assessed independently for their effect on plasma and liver cholesterol concentration. Hamsters were divided into four dietary groups and fed diets containing 0.12% cholesterol and 5% fiber as high viscosity hydroxypropyl methylcellulose (HV-HPMC group), low viscosity hydroxypropyl methylcellulose (LV-HPMC group), high viscosity guar gum (HV-GG group) or low viscosity guar gum (LV-GG group). Hydroxypropyl methylcellulose is essentially nonfermentable, whereas guar gum is highly fermentable. Plasma cholesterol concentrations at 3, 6 and 11 wk and liver cholesterol concentrations at 6 and 11 wk were significantly lower in the HV-HPMC group relative to the LV-HPMC group (P < 0.05). Intestinal content viscosities of the LV-HPMC and HV-GG groups were similar; consequently, these two groups were compared to examine the independent effect of fermentation. Plasma and liver cholesterol were significantly lower in the HV-GG group compared with the LV-HPMC group at 6 wk (P < 0.05), but not at 3 or 11 wk. Hepatic sterol synthesis rates were not affected by any of the diets. This study shows that greater viscosity of intestinal contents is strongly associated with cholesterol reduction, but that the contribution of fiber fermentation remains uncertain.

Animals↗
PubMed1993

Fiber and large bowel energy absorption: validation of the integrated ileostomy-fermentation model using pigs.

Controversy exists over the contribution of dietary fiber and large bowel fermentation to human energy balance. It has been suggested that large bowel energy absorption, in the form of short-chain fatty acids, can be predicted from in vitro fermentation of human ileal digesta. Because it is difficult to obtain ileal digesta from humans with a functional large bowel to validate this approach, four normal pigs and four pigs fitted with a simple T-cannula at the distal ileum were fed a basal diet supplemented with 0, 5, 10 or 15 g pea fiber per 100 g basal diet in two parallel experiments (Latin-square design). Energy contents of diets, urine, ileal digesta and feces were determined by bomb calorimetry. Apparent total tract energy digestibility did not differ (P > 0.05) between normal and cannulated pigs. Apparent energy digestibility at the ileum decreased with increasing pea fiber intake (P < 0.05). The difference between ileal and fecal gross energy excretions in cannulated pigs was defined as large bowel energy absorption. Aliquots (0.2 g) of freeze-dried ileal digesta were fermented in vitro for 24 h with human fecal inoculum from three donors. In vitro short-chain fatty acid production was correlated with large bowel energy absorption (r = 0.90, P < 0.0001). The metabolizable energy content of pea fiber was determined to be 9.2 kJ/g pea fiber (r = 0.90, P < 0.0001) by regressing metabolizable energy retention against pea fiber intake. The integrated ileostomy-in vitro fermentation model seems to provide accurate estimates of large bowel energy absorption.

Animals↗
PubMed1997

Administration of transgalacto-oligosaccharides increases fecal bifidobacteria and modifies colonic fermentation metabolism in healthy humans.

Transgalacto-oligosaccharides are a mixture of oligosaccharides consisting of glucose and galactose; they are not digested in the human small intestine. In vitro, they specifically stimulate the growth of bifidobacteria. The aim of the present work was to assess tolerance of transgalacto-oligosaccharides and the effects of their prolonged administration on bifidobacteria and fermentative activity of colonic flora. Eight healthy subjects were given 10 g of transgalacto-oligosaccharides per day for 21 d in two daily doses. A breath test and stool sample collection were carried out on d 1, 7, 14 and 21 of transgalacto-oligosaccharides ingestion. The stools of three subjects were collected and mixed before the study, and then inoculated in vitro into a fermentor to which 10 g transgalacto-oligosaccharides was added daily for 14 d. In the eight volunteers, administration of transgalacto-oligosaccharides led to a significant decrease in breath hydrogen excretion (P < 0.01) and a significant increase in fecal concentrations of bifidobacteria from (means +/- SEM) 8.6 +/- 0.6 to 9.7 +/- 0.5, 9.7 +/- 0.6 and 9.5 +/- 0.6 log colony-forming units (CFU)/g on d 1, 7, 14 and 21, respectively (P < 0.05). Fecal concentrations of enterobacteria, as well as stool weight, fecal water and pH did not change during the study. In vitro, transgalacto-oligosaccharides fermentation became more efficient and faster with time. In addition, metabolic alterations such as a rise in acetate proportion and lactate formation after 7 d of fermentation were observed, indicating the transformation of the inoculated fecal flora into an acid-resistant lactic flora. Prolonged administration of transgalacto-oligosaccharides, at a dose which does not induce digestive symptoms, increases the number of bifidobacteria and alters the fermentative activity of colonic flora in humans.

Adult↗