Fermentation

Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Fermentation

  • acid fermentation
  • alcoholic fermentation
  • anaerobic fermentation
  • bacterial fermentation
  • batch fermentation
  • carbohydrate fermentation
  • coli fermentation
  • continuous fermentation
  • escherichia coli fermentation
  • ethanol fermentation
  • fed-batch fermentation
  • glucose fermentation
  • h fermentation
  • lactic acid fermentation
  • malolactic fermentation
  • microbial fermentation
  • natural fermentation
  • rumen fermentation
  • ruminal fermentation
  • solid-state fermentation
  • sourdough fermentation
  • spontaneous fermentation
  • submerged fermentation
  • subsequent fermentation
  • vitro fermentation
  • wine fermentation
  • xylose fermentation
  • yeast fermentation

  • Terms modified by Fermentation

  • fermentation ability
  • fermentation activity
  • fermentation broth
  • fermentation characteristic
  • fermentation condition
  • fermentation kinetics
  • fermentation media
  • fermentation medium
  • fermentation parameter
  • fermentation pathway
  • fermentation pattern
  • fermentation performance
  • fermentation period
  • fermentation ph
  • fermentation process
  • fermentation product
  • fermentation products
  • fermentation profile
  • fermentation rate
  • fermentation strategy
  • fermentation system
  • fermentation technology
  • fermentation time

  • Selected Abstracts


    EFFECT OF LACTIC ACID FERMENTATION OF CASSAVA ON FUNCTIONAL AND SENSORY CHARACTERISTICS OF FUFU FLOUR

    JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2008
    A.O. SOBOWALE
    ABSTRACT The effects of lactic acid fermentation of cassava on the functional and sensory characteristic of fufu flour were investigated. Two strains of Lactobacillus plantarum were used as starter cultures for the fermentation of cassava to fufu for 96 h. The resultant wet fufu samples were dried at 65C in a cabinet dryer for 48 h, and were analyzed for functional and sensory characteristics. Fermentation reduced the water-binding capacity of the fufu flour from 176.6% to between 118 and 125%. The pasting characteristics of the traditional and starter culture-fermented fufu flour samples were not significantly different from that of the unfermented cassava flour. When subjected to sensory evaluation, the traditional and starter culture-fermented cassava fufu flour were not significantly different in terms of color, odor and texture, but the cassava fufu flour produced, using starter culture SL19, had the highest overall acceptability (P < 0.05). PRACTICAL APPLICATIONS Traditionally, processing of cassava to fufu is usually carried out by using the old stock from a previous fermentation to initiate the fermentation of a new batch. This old method usually results in fufu that has a strong odor that may not be acceptable to some consumers. The use of starter culture like Lactobacillus plantarum will reduce the strong odor of fufu; this will increase its acceptability by consumers and ensure the overall quality. Also, the functional properties of fufu are not affected. The development of lactobacilli strains could help in optimizing the traditional processes, therefore increasing the economic returns. [source]


    STUDIES ON THE FERMENTATION OF TOMATO JUICE BY USING ,-CARRAGEENAN IMMOBILIZED LACTOBACILLUS ACIDOPHILUS

    JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2008
    JEN-HORNG TSEN
    ABSTRACT Lactobacillus acidophilus was entrapped in ,-carrageenan and used to perform tomato juice fermentation in order to raise the survival of the bacteria in the product. Gel beads with diameters approximately 3.0 mm for cell immobilization were obtained, fresh raw tomatoes were used to make the juice and both free and immobilized cells were applied to carry out the fermentation for 80 h. Cell leakage from the gel beads and proliferation in the juice during the fermentation of immobilized cells were observed. The final viable cell number was attained with 107 cfu/mL in the juice, over 1010 cfu/mL-gel in gel beads for the fermentation of immobilized cell, and ca. 109 cfu/mL for the free cell. Immobilized cells could withstand the unfavorable low pH environment in tomato juice and better growth was achieved compared with free cells. The viable cell counts of immobilized L. acidophilus in the fermented tomato juice could maintain the level of 106 cfu/mL-gel after 10 weeks of cold storage at 4C, in comparison with 104 cfu/mL for free cells. The immobilized cell fermented tomato juice also showed better overall palatability than that of free cells in cold storage at 4C. PRACTICAL APPLICATIONS This study demonstrates the applicability of ,-carrageenan immobilized Lactobacillus acidophilus in the fermentation of tomato juice. The unfavorable low pH condition in tomato juice could be overcome and certain benefits were provided by cell immobilization. [source]


    DETERMINATION OF ULTRASONIC-BASED RHEOLOGICAL PROPERTIES OF DOUGH DURING FERMENTATION,

    JOURNAL OF TEXTURE STUDIES, Issue 1 2004
    SUYONG LEE
    ABSTRACT An ultrasonic technique was used to study the changes of the rheological properties of dough during fermentation at 37C and compared with the extensional properties of fermented dough obtained from tensile tests carried out in a Universal Testing Maching. The velocity and attenuation of a longitudinal wave (P-wave) propagated through the dough samples were measured and analyzed to obtain the viscoelastic moduli of the dough; the storage modulus M' and the loss modulus M". These moduli include both the bulk and the shear moduli. A wavelet analysis also was used to determine the effect of frequency on the ultrasonic-based viscoelastic moduli and the effect of the fermentation process on the ultrasonic velocity dispersion. A decrease in ultrasonic velocity was observed with increasing fermentation times. Ultrasonic waves were strongly attenuated in the dough subjected to long fermentation times and fermentation had a large influence on the viscoelastic moduli of the dough. The ultrasonic velocity increased with increasing frequency, clearly showing the viscoelastic nature of the fermented dough. The analysis also showed significant ultrasonic velocity dispersion upon fermentation. Ultrasonic measurements yielded results that agreed with those obtained from conventional rheology commonly used to characterize the extensional properties of dough. Both tests clearly showed the loss of elasticity by the dough samples upon fermentation. [source]


    COMPARISON OF HEADSPACE SOLID PHASE MICROEXTRACTION AND XAD-2 METHODS TO EXTRACT VOLATILE COMPOUNDS PRODUCED BY SACCHAROMYCES DURING WINE FERMENTATIONS

    JOURNAL OF FOOD QUALITY, Issue 1 2006
    JEFFRI C. BOHLSCHEID
    ABSTRACT A modified headspace solid phase microextraction (HS-SPME) method was compared with Amberlite® XAD-2 resin for the extraction of volatile compounds. In the HS-SPME method, volatiles were extracted using an 85 ,m polyacrylate fiber from wines that contained a standardized amount of ethanol (10% v/v), NaCl (0.325 g/mL) and internal standards (dodecanol and nonanoic acid). Both extraction procedures yielded high relative recoveries (>92%) and reproducibilities (coefficient of variations , 11%) for the different higher alcohols, esters and medium-chain fatty acids. Overall, limits of detection for the HS-SPME and XAD-2 methods were below sensory threshold concentrations. HS-SPME and XAD-2 performed similarly in the analysis of a Riesling wine; however, the HS-SPME method did not require organic solvents and was generally quicker to perform. In applying the HS-SPME method, differences in concentrations of volatile compounds produced in Riesling and Chenin blanc wines by 11 different yeast strains were noted. [source]


    Acclimation Strategy of a Biohydrogen Producing Population in a Continuous-Flow Reactor with Carbohydrate Fermentation

    ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2006
    Q. Ren
    Abstract Poor startup of biological hydrogen production systems can cause an ineffective hydrogen production rate and poor biomass growth at a high hydraulic retention time (HRT), or cause a prolonged period of acclimation. In this paper a new startup strategy was developed in order to improve the enrichment of the hydrogen-producing population and the efficiency of hydrogen production. A continuously-stirred tank reactor (CSTR) and molasses were used to evaluate the hydrogen productivity of the sewage sludge microflora at a temperature of 35,°C. The experimental results indicated that the feed to microorganism ratio (F/M ratio) was a key parameter for the enrichment of hydrogen producing sludge in a continuous-flow reactor. When the initial biomass was inoculated with 6.24,g of volatile suspended solids (VSS)/L, an HRT of 6,h, an initial organic loading rate (OLR) of 7.0,kg chemical oxygen demand (COD)/(m3,×,d) and an feed to microorganism ratio (F/M) ratio of about 2,3,g COD/(g of volatile suspended solids (VSS) per day) were maintained during startup. Under these conditions, a hydrogen producing population at an equilibrium state could be established within 30,days. The main liquid fermentation products were acetate and ethanol. Biogas was composed of H2 and CO2. The hydrogen content in the biogas amounted to 47.5,%. The average hydrogen yield was 2.01,mol/mol hexose consumed. It was also observed that a special hydrogen producing population was formed when this startup strategy was used. It is supposed that the population may have had some special metabolic pathways to produce hydrogen along with ethanol as the main fermentation products. [source]


    The Composition of Jerusalem Artichoke (Helianthus tuberosus L.) Spirits Obtained from Fermentation with Bacteria and Yeasts

    ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 1 2005
    K. Szambelan
    Abstract The composition of spirits distilled from fermentation of Jerusalem artichoke (Helianthus tuberosus L.) tubers was compared by means of gas chromatography. The microorganisms used in the fermentation processes were the bacterium Zymomonas mobilis, strains,3881 and 3883, the distillery yeast Saccharomyces cerevisiae, strains,Bc16a and D2 and the Kluyveromyces fragilis yeast with an active inulinase. The fermentation of mashed tubers was conducted using a single culture of the distillery yeast Saccharomyces cerevisiae and the bacterium Zymomonas mobilis (after acid or enzymatic hydrolysis) as well as Kluyveromyces fragilis (sterilized mashed tubers). The tubers were simultaneously fermented by mixed cultures of the bacterium or the distillery yeast with K.,fragilis. The highest ethanol yield was achieved when Z.,mobilis,3881 with a yeast demonstrating inulinase activity was applied. The yield reached 94,% of the theoretical value. It was found that the distillates resulting from the fermentation of mixed cultures were characterized by a relatively lower amount of by-products compared to the distillates resulting from the single species process. Ester production of 0.30,2.93,g/L, responsible for the aromatic quality of the spirits, was noticed when K.,fragilis was applied for ethanol fermentation both in a single culture process and also in the mixed fermentation with the bacterium. Yeast applied in this study caused the formation of higher alcohols to concentrations of 7.04,g/L much greater than those obtained with the bacterium. The concentrations of compounds other than ethanol obtained from Jerusalem artichoke mashed tubers, which were fermented by Z.,mobilis, were lower than those achieved for yeasts. [source]


    The Kluyver effect revisited

    FEMS YEAST RESEARCH, Issue 4 2003
    Hiroshi Fukuhara
    Abstract Yeast species can grow on various sugars. However, in many cases the growth on certain sugars (especially oligosaccharides) occurs only under aerobic conditions, and not in anaerobiosis or in the absence of respiration. Fermentation is blocked under these conditions. This apparent dependence of sugar utilization on the respiration has been called Kluyver effect, and such ,respiration-dependent' species are called Kluyver effect positive. A yeast may be Kluyver effect positive for some sugars and not for others. The physiological meaning and the molecular basis of the phenomenon are not clear. It has recently been reported that Kluyveromyces lactis, which is Kluyver effect positive for galactose and a few other sugars, could be converted into a Kluyver effect-negative form by introduction of relevant sugar transporter genes. Such results offer for the first time a direct support to the hypothesis that the immediate cause of the Kluyver effect may be the low level of sugar transporter activities which is not sufficient to sustain the high substrate flow necessary for fermentative growth, whereas the energy-efficient respiratory growth does not require a high rate of sugar uptake. We examined to what extent this sugar transporter theory of the Kluyver effect can be generalized. [source]


    The effect of harvest date and inoculation on the yield, fermentation characteristics and feeding value of forage pea and field bean silages

    GRASS & FORAGE SCIENCE, Issue 3 2001
    M. D. Fraser
    Two experiments describe the ensiling potential of whole-crop forage peas (Pisum sativum) and field beans (Vicia faba). In Experiment 1, forage peas (cv. Magnus) and field beans (cv. Mayo) were harvested at 10, 12 and 14 weeks after sowing, and ensiled in 10 kg mini-silos either untreated or treated with an inoculant (Lactobacillus plantarum). In terms of yield and ensiling potential, the optimum growth stage for harvesting forage peas occurred at 12 weeks of growth. In contrast, delaying the harvest of field beans until 14 weeks gave the highest yields of dry matter (DM) and crude protein (CP). Changes in crop maturity had little effect on the chemical composition of the fresh forages, but between-harvest date differences were observed in the DM, ammonia-N, CP, water-soluble carbohydrates (WSC), acid-detergent fibre (ADF), neutral-detergent fibre (NDF), lactic acid and volatile fatty acids (VFA) concentrations and pH of the corresponding silages. Fermentation was improved by applying an inoculant. In Experiment 2, forage peas and field beans were harvested at 14 weeks after sowing and ensiled as round-bale silage, either untreated or treated with an inoculant. The yields of the crops were similar, and the only difference in the chemical composition of the wilted forages was a higher CP concentration in the field beans. However, after the ensiling process was complete, the forage pea silages were found to have significantly higher DM, WSC, starch and butyric acid concentrations compared with the field bean silages, and lower ammonia-N, CP, ADF, acetic acid and lactic acid concentrations. Inoculation was found to increase the lactic acid concentration and reduce the pH and ammonia-N and acetic acid concentrations of the silages. Each of the silages produced in Experiment 2 was offered to six Suffolk crossbred wether lambs, aged 10 months. Voluntary DM intakes were similar on all treatments, despite the apparent digestibility of the forage pea silages being significantly higher than that of the field bean silages. Nitrogen retention was higher for lambs offered forage pea silage. Application of an inoculant was found to have a negative effect on the amount of N retained, indicating the necessity for more detailed investigations into proteolytic activity within these crops during the fermentation process. [source]


    Effect of fermentation on in vitro digestibilities and the level of antinutrients in moth bean [Vigna aconitifolia (Jacq.) Marechal]

    INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 11 2008
    Amrit Bhandal
    Summary The effect of fermentation with varying temperatures and time periods on the nutritive value of Moth bean was studied. Results indicated that at 30 °C, protein digestibility increased from 60% in the non-processed moth bean to 77%, 78% and 80% and at 35 °C, increased to 81%, 83% and 85% following 12, 18 and 24 h of fermentation (controlled) period, respectively. Fermentation also caused an appreciable enhancement (96,133%) in starch digestibility with increase in period and temperature of fermentation. Fermentation of moth bean resulted in 24,34% reduction in phytic acid content at 30 °C and 33,42.5% at 35 °C. Polyphenol content was reduced by 42%, 48% and 51% at 30 °C and by 44%, 49% and 54% at 35 °C after 12, 18 and 24 h of fermentation period, respectively. Prolonging the period of fermentation from 12 to 18 and 24 h at 30 °C also caused a loss in TIA. [source]


    Effect of lactic acid fermentation of onions (Allium cepa) on the composition of flavonol glucosides

    INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2007
    Barbara Bisakowski
    Summary Fermentation of red onions inoculated with Lactobacillus plantarum S1 (starter treatment) resulted in acid production to pH 4.5, after 48 h of incubation at 19 °C, which has proven to be adequate for proper preservation. In the presence of erythromycin (starter + antibiotic), acidification to pH 5.2 resulted, which was similar to that of the uninoculated control. The bacterial population was about 108 CFU mL,1 of brine after 3 days for the three treatments, suggesting that in the starter + antibiotic treatment, the antibiotic effectively suppressed the activity of the starter but not the native flora. Before lactic fermentation, the red onions contained 297.4 mg of total quercetin (Q) per kg wet weight, which consisted of 58.3%, 41.6% and 0.1% in quercetin diglucoside (Qdg), quercetin monoglucoside (Qmg) and free Q, respectively. For the starter treatment, Qdg decreased to 41.8% and 18.3% at 48 and 72 h, respectively, and a substantial amount of free Q had accumulated. The fermentation substantially increased the proportion of Qmg, which may have a positive effect as fractions containing higher ratios of Qmg to Qdg have been reported to have higher antioxidant activity. [source]


    Inhibition of ruminal microbial methane production by ,-cyclodextrin iodopropane, malate and their combination in vitro

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 5-6 2004
    N. Mohammed
    Summary The objective of this study was to evaluate the effects of different concentrations of l -malate (0, 5, 10 and 20 mm), 2-iodopropane- , -cyclodextrin complex (CD-IP) (0, 0.1, 0.2 and 0.4 mm) and a combination of malate (10 and 20 mm) plus CD-IP (0.2 and 0.4 mm) on methane production from corn starch. Ruminal fluid was collected from dairy cows, mixed with phosphate buffer (1 : 2) and incubated (30 ml) anaerobically at 38 °C for 6 h with or without additives. Fermentation of corn starch in the presence of malate resulted in an increase (p < 0.05) in pH of the medium, total volatile fatty acid (VFA), total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were unchanged. Methane production was decreased (p < 0.05) (15.5 to 20.4%). Addition of CD-IP in corn starch resulted in an increase (p < 0.05) in total VFA and molar proportion of propionate. Acetate, pH and ammonia-N concentration of the medium were decreased (p < 0.05). Total gas production was unchanged. Methane production was decreased (p < 0.05) (25.2 to 97.1%) and hydrogen production was increased (p < 0.05). Addition of l -malate to CD-IP resulted in an increase (p < 0.05) in total VFA, total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were decreased (p < 0.05). No effects were observed on medium pH. Methane production was decreased (p < 0.05) (49.5 to 97.1%). Hydrogen production was also decreased (p < 0.05) (54.5 to 64.1%) compared with those of CD-IP alone. Therefore, these additives may be used as supplements to inhibit methane production as well as to improve rumen fermentation and animal performance. [source]


    Nutritional evaluation of fermented black gram (Phaseolus mungo) seed meal in compound diets for rohu, Labeo rohita (Hamilton), fingerlings

    JOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2007
    S. Ramachandran
    Summary Six isonitrogenous (approximately 35% crude protein) and isocaloric (approximately 4.0 kcal g,1) diets were formulated incorporating raw and fermented black gram, Phaseolus mungo, seed meal at 20%, 30% and 40% levels by weight into a fishmeal-based control diet fed to rohu, Labeo rohita, fingerlings (mean weight, 1.81 ± 0.21 g) for 80 days for a study of fish performance. A particular bacterial strain (Bacillus sp.) isolated from the intestine of adult common carp (Cyprinus carpio) reared in the wild having significant amylolytic, cellulolytic, lipolytic and proteolytic activities was used for fermentation of seed meal for 15 days at 37 ± 2°C. Fermentation of P. mungo seed meal was effective in significantly reducing the crude fibre content and antinutritional factors such as tannins and phytic acid, and enhancing available free amino acids and fatty acids. In terms of growth, feed conversion ratio and protein efficiency ratio, the 30% fermented black gram seed meal incorporated diet resulted in a significantly (P < 0.05) better performance of rohu fingerlings. In general, growth and feed utilization efficiencies of diets containing fermented seed meal were superior to diets containing raw seed meal. The apparent protein digestibility (APD) values decreased with increasing levels of raw seed meal in the diets. The APD for raw seed meal was lower at all levels of inclusion in comparison to those for the fermented seed meals. The maximum deposition of protein in the carcass was recorded in fish fed the diet containing 40% fermented seed meal. The results indicate that fermented black gram seed meal can be incorporated in carp diets up to the 30% level compared to the 10% level of raw seed meal. [source]


    Fermentation of glucose and starch particles using an inexpensive medium

    JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2010
    Nancy Bawa
    Abstract BACKGROUND: In North America, compared with sugar, starch is a more economical raw material to produce ethanol. Recently low temperature processing of starch granules directly to ethanol has been commercialized. With a view to minimizing process costs while maintaining a satisfactory ethanol yield, an inexpensive medium that does not require the addition of commercial ,-amylase has been developed for low temperature, direct fermentation of starch particles. RESULTS: Compared with an expensive medium that contained both yeast extract and ,-amylase, the inexpensive medium resulted in identical and 10% higher ethanol yields using glucose and starch granules as the raw substrates, respectively, but required longer processing times. Based on the different ingredient prices for expensive and inexpensive media, the operating cost to produce 10 million litres per year of ethanol utilizing simultaneous raw starch hydrolysis and fermentation is reduced over $ 2 million (Cdn) per year when using inexpensive medium. CONCLUSION: The new inexpensive medium and simultaneous raw starch hydrolysis and fermentation is considered the best strategy to produce ethanol directly from starch particles in North America. Copyright © 2009 Society of Chemical Industry [source]


    Fermentation of enzymatic hydrolysates from olive stones by Pachysolen tannophilus

    JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2009
    Manuel Cuevas
    Abstract BACKGROUND: Olive stones were pretreated with liquid hot water (LHW or autohydrolysis) at maximum temperatures between 175 and 225 °C (severity factors, logR0, between 2.73 and 4.39) to be subjected (both liquid and solid components) afterwards to enzymatic hydrolysis with cellulases from Trichoderma viride. Ethanol fermentation of hydrolysates was performed with the non-traditional yeast Pachysolen tannophilus ATCC 32691. RESULTS: After the enzymatic step, yields of hemicellulose solubilization reached 100%, while the cellulose was only partially hydrolysed (23%, logR0 = 4.39). The maximum yields in total reducing sugars and acetic acid, at the upper end of the severity range, was close to 0.25 and 0.04 g g,1 dry stone, respectively. During the fermentation stage, the increase in R0 reduced the maximum specific growth rate, biomass productivity, and overall biomass yield. The overall yields of ethanol and xylitol ranged, respectively, from 0.18 to 0.25 g g,1 and from 0.01 to 0.13 g g,1. CONCLUSIONS: The results demonstrate the possibility of producing ethanol from olive stones, making use of the cellulose and hemicellulose fraction of the waste. It was confirmed that the overall yield in xylitol strongly depended on severity factor, while the overall yield in ethanol remained practically constant for all the pretreatment conditions tested. Copyright © 2008 Society of Chemical Industry [source]


    EFFECT OF LACTIC ACID FERMENTATION OF CASSAVA ON FUNCTIONAL AND SENSORY CHARACTERISTICS OF FUFU FLOUR

    JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2008
    A.O. SOBOWALE
    ABSTRACT The effects of lactic acid fermentation of cassava on the functional and sensory characteristic of fufu flour were investigated. Two strains of Lactobacillus plantarum were used as starter cultures for the fermentation of cassava to fufu for 96 h. The resultant wet fufu samples were dried at 65C in a cabinet dryer for 48 h, and were analyzed for functional and sensory characteristics. Fermentation reduced the water-binding capacity of the fufu flour from 176.6% to between 118 and 125%. The pasting characteristics of the traditional and starter culture-fermented fufu flour samples were not significantly different from that of the unfermented cassava flour. When subjected to sensory evaluation, the traditional and starter culture-fermented cassava fufu flour were not significantly different in terms of color, odor and texture, but the cassava fufu flour produced, using starter culture SL19, had the highest overall acceptability (P < 0.05). PRACTICAL APPLICATIONS Traditionally, processing of cassava to fufu is usually carried out by using the old stock from a previous fermentation to initiate the fermentation of a new batch. This old method usually results in fufu that has a strong odor that may not be acceptable to some consumers. The use of starter culture like Lactobacillus plantarum will reduce the strong odor of fufu; this will increase its acceptability by consumers and ensure the overall quality. Also, the functional properties of fufu are not affected. The development of lactobacilli strains could help in optimizing the traditional processes, therefore increasing the economic returns. [source]


    Ghanaian Cocoa Bean Fermentation Characterized by Spectroscopic and Chromatographic Methods and Chemometrics

    JOURNAL OF FOOD SCIENCE, Issue 6 2010
    Patrick C. Aculey
    Abstract:, Export of cocoa beans is of great economic importance in Ghana and several other tropical countries. Raw cocoa has an astringent, unpleasant taste, and flavor, and has to be fermented, dried, and roasted to obtain the characteristic cocoa flavor and taste. In an attempt to obtain a deeper understanding of the changes in the cocoa beans during fermentation and investigate the possibility of future development of objective methods for assessing the degree of fermentation, a novel combination of methods including cut test, colorimetry, fluorescence spectroscopy, NIR spectroscopy, and GC-MS evaluated by chemometric methods was used to examine cocoa beans sampled at different durations of fermentation and samples representing fully fermented and dried beans from all cocoa growing regions of Ghana. Using colorimetry it was found that samples moved towards higher,a* and,b* values as fermentation progressed. Furthermore, the degree of fermentation could, in general, be well described by the spectroscopic methods used. In addition, it was possible to link analysis of volatile compounds with predictions of fermentation time. Fermented and dried cocoa beans from the Volta and the Western regions clustered separately in the score plots based on colorimetric, fluorescence, NIR, and GC-MS indicating regional differences in the composition of Ghanaian cocoa beans. The study demonstrates the potential of colorimetry and spectroscopic methods as valuable tools for determining the fermentation degree of cocoa beans. Using GC-MS it was possible to demonstrate the formation of several important aroma compounds such 2-phenylethyl acetate, propionic acid, and acetoin and the breakdown of others like diacetyl during fermentation. Practical Application:, The present study demonstrates the potential of using colorimetry and spectroscopic methods as objective methods for determining cocoa bean quality along the processing chain. Development of objective methods for determining cocoa bean quality will be of great importance for quality insurance within the fields of cocoa processing and raw material control in chocolate producing companies. [source]


    Fermentation of Cucumbers Brined with Calcium Chloride Instead of Sodium Chloride

    JOURNAL OF FOOD SCIENCE, Issue 3 2010
    Roger F. McFeeters
    ABSTRACT:, Waste water containing high levels of NaCl from cucumber fermentation tank yards is a continuing problem for the pickled vegetable industry. A major reduction in waste salt could be achieved if NaCl were eliminated from the cucumber fermentation process. The objectives of this project were to ferment cucumbers in brine containing CaCl2 as the only salt, to determine the course of fermentation metabolism in the absence of NaCl, and to compare firmness retention of cucumbers fermented in CaCl2 brine during subsequent storage compared to cucumbers fermented in brines containing both NaCl and CaCl2 at concentrations typically used in commercial fermentations. The major metabolite changes during fermentation without NaCl were conversion of sugars in the fresh cucumbers primarily to lactic acid which caused pH to decrease to less than 3.5. This is the same pattern that occurs when cucumbers are fermented with NaCl as the major brining salt. Lactic acid concentration and pH were stable during storage and there was no detectable production of propionic acid or butyric acid that would indicate growth of spoilage bacteria. Firmness retention in cucumbers fermented with 100 to 300 mM CaCl2 during storage at a high temperature (45 °C) was not significantly different from that obtained in fermented cucumbers with 1.03 M NaCl and 40 mM CaCl2. In closed jars, cucumber fermentations with and without NaCl in the fermentation brine were similar both in the chemical changes caused by the fermentative microorganisms and in the retention of firmness in the fermented cucumbers. [source]


    Optimization of Medium Composition for Nisin Fermentation with Response Surface Methodology

    JOURNAL OF FOOD SCIENCE, Issue 6 2008
    X.-X. Zhou
    ABSTRACT:, Nisin is an effective food biopreservative widely used in food industry. However, 1 problem of concern is limited production rate and final nisin concentration. A nisin-producing strain, L. lactis Lac2, a mutant strain with high yield of nisin, was obtained in our laboratory recently. In the present study, a fractional factorial design was applied to investigate the main factors that affect the yield of L. lactis Lac2. Central composite experimental design and response surface methodology were adopted to derive a statistical model for optimizing the composition of the medium. The results showed that the optimum medium for nisin production of L. lactis Lac2 was composed of 2.68% sucrose (w/v), 0.5% tryptone (w/v), 1% yeast extract (w/v), 0.3% Tween-80 (w/v), 0.02% MgSO4·7H2O (w/v), 0.81% NaCl (w/v), 1.91% K2HPO4 (w/v), 0.05% ascorbic acid (w/v), and 2% agar (w/v) (if necessary) at pH 6.5. When cultured in the optimum medium, the nisin yield is an average of 3381.81 IU/mL, which nearly doubled the yield when incubated in the initial medium. Also, the concentration of tryptone was decreased while that of the sucrose was increased when compared with CM broth, which means a reduction of the fermentation cost. [source]


    Fermentation of Reconstituted Skim Milk Supplemented with Soy Protein Isolate by Probiotic Organisms

    JOURNAL OF FOOD SCIENCE, Issue 2 2008
    T.T. Pham
    ABSTRACT:, Utilization of lactose and production of organic acid were determined in reconstituted skim milk (RSM) and RSM supplemented with soy protein isolate (SPI) (RSMS) by 6 probiotic organisms, including L. acidophilus 4461, L. acidophilus 4962, L. casei 290, L. casei 2607, B. animalis subsp. lactis bb12, and B. longum 20099. The viable counts of probiotic organisms of RSM and RSMS were enumerated and pH measured during fermentation. Our results showed that 3% to 10% more lactose was utilized by all the 6 probiotic microorganisms from RSMS than RSM. All 6 probiotic organisms produced significantly more acetic acid in RSMS than RSM. However, the viable microbial populations in RSMS were lower than those in RSM due to lower pH of the former. It appears that addition of SPI enhanced lactose utilization and acetic acid production but slightly reduced the lactic acid production and the growth of probiotic microorganisms. [source]


    Effects of Leuconostoc mesenteroides Starter Culture on Fermentation of Cabbage with Reduced Salt Concentrations

    JOURNAL OF FOOD SCIENCE, Issue 5 2007
    Suzanne Johanningsmeier
    ABSTRACT:, Sauerkraut fermentations rely upon selection of naturally occurring lactic acid bacteria by addition of 2.0% to 2.25% granulated sodium chloride (NaCl) to shredded cabbage. Excess brine generated is a waste product with high levels of organic material (BOD) and nonbiodegradable NaCl. The objective was to determine whether addition of Leuconostoc mesenteroides starter culture to reduced-salt cabbage fermentations would yield sauerkraut with reproducible and acceptable chemical composition and sensory qualities. Shredded cabbage was salted with 0.5%, 1.0%, or 2.0% NaCl (wt/wt) at 2 starter culture levels, none or L. mesenteroides strain LA 81, ATCC 8293 (106 CFU/g). Fermentation products were quantified by high-performance liquid chromatography, and pH was measured during the initial stages of fermentation and after 10 mo storage at 18 °C. A trained descriptive sensory panel used category scales to rate the flavor and texture of selected sauerkrauts. A modified Kramer shear test was used to measure firmness. Cabbage fermented with L. mesenteroides consistently resulted in sauerkraut with firm texture and reduced off-flavors across all salt levels (P < 0.05). Conversely, sauerkraut quality was highly variable, with softening and off-flavors occurring as salt concentrations were decreased in natural fermentations (P < 0.05). Fermentations were rapid, with a more uniform decline in pH when starter culture was added. L. mesenteroides addition to cabbage fermentations ensured that texture and flavor quality were retained, while allowing 50% NaCl reduction. Application of this technology to commercial sauerkraut production could improve the uniformity of fermentations and substantially reduce generation of nonbiodegradable chloride waste. [source]


    Effect of Combining Proteolysis and Lactic Acid Bacterial Fermentation on the Characteristics of Minced Mackerel

    JOURNAL OF FOOD SCIENCE, Issue 3 2005
    Li-Jung Yin
    ABSTRACT: To improve the quality of fish muscle, mackerel muscle protein was hydrolyzed by proteases from Aspergillus oryzae, and then fermented by lactic acid bacteria (LAB). The highest protease activities were obtained from A. oryzae after 72 h incubation at 25°C. Acidic protease activity was much higher than neutral and alkaline proteases. SDS-PAGE indicated the degradation of muscle proteins after 1 or 2 h hydrolysis by A. oryzae proteases at 50°C. During 48 h fermentation by Pediococcus pentosaceus L and S at 37°C, rapid growth of LAB, decline in pH, and suppression in the growth of microflora, Enterobacteriaceae, Staphylococcus, and Pseudomonas, occurred while increases in whiteness, nonprotein nitrogen, sensory quality, and free amino acids were observed. These data suggested that the acceptability of LAB -fermented mackerel hydrolysates could be substantially improved. [source]


    Malolactic Activity of Lactic Acid Bacteria during Sauerkraut Fermentation

    JOURNAL OF FOOD SCIENCE, Issue 8 2004
    S.D. Johanningsmeier
    ABSTRACT: The frequency of lactic acid bacteria (LAB) involved in sauerkraut fermentation with (MDC+) or without (MDC - ) the ability to decarboxylate malic acid was determined. The MDC+ phenotype was found in > 99% of homofermentative LAB isolated from commercial fermentations. In contrast, heterofermentative LAB isolates from 0.25, 3, 7, and 10 d had only 53%, 54%, 15%, and 11% MDC+ phenotype, respectively, indicating that more than 1 strain or species was involved. The malolactic reaction was demonstrated in cabbage juice with known strains of Leuconostoc mesenteroides, raising the question of desirability of such activity in cultures selected for the controlled fermentation of cabbage. [source]


    Irradiation Effects on Biogenic Amines in Korean Fermented Soybean Paste During Fermentation

    JOURNAL OF FOOD SCIENCE, Issue 1 2003
    J.-H. Kim
    ABSTRACT: Irradiation effects on biogenic amines (BAs) and microbiological populations of Korean fermented soybean paste were investigated during fermentation. Soybean paste was prepared and irradiated with doses of 5,10, and 15 kGy, and then fermented at 25 °C for 12 wk. Bacillus spp. and lactic-acid bacteria decreased by irradiation but increased during fermentation. Biogenic amines detected were putrescine, cadaverine, ,-phenylethylamine, spermidine, spermine, tryptamine, histamine, tyramine, and agmatine. A significant difference was not observed in BA content between control and irradiated samples immediately after gamma irradiation. However, 4 kinds of BAs, putrescine, tryptamine, spermidine, and histamine, showed significant reduction by irradiation during fermentation (P < 0.05). [source]


    Enzymic Transformation of Isoflavone Phytoestrogens in Soymilk by ,-Glucosidase-Producing Bifidobacteria

    JOURNAL OF FOOD SCIENCE, Issue 8 2002
    D. Tsangalis
    ABSTRACT: Five strains of bifidobacteria were screened for ,-glucosidase activity using p-nitrophenyl-,-D-glucopyranoside as the substrate, and selected strains were used to ferment soymilk. Enumeration of viable bifidobacteria and quantification of isoflavones using HPLC were performed at 0, 12, 24, 36, and 48 h of incubation. Four strains produced ,-glucosidase. B. pseudolongum and B. longum -a displayed the best growth in soymilk, with an increase of 1.3 log10 CFU/mL after 12 h. B. animalis, B. longum -a, and B. pseudolongum caused hydrolysis of isoflavone malonyl-, acetyl- and ,-glucosides to form aglycones, and transformed daidzein to equol in soymilk. Fermentation of soymilk with Bifidobacterium sp. resulted in a significant increase (p < 0.05) in the concentration of aglycones. [source]


    Increase of Conjugated Linoleic Acid Content in Milk by Fermentation with Lactic Acid Bacteria

    JOURNAL OF FOOD SCIENCE, Issue 5 2002
    Y.J. Kim
    ABSTRACT: The objectives of this study were to identify the factors and procedures responsible for increasing the conjugated linoleic acid (CLA) content in fermented milk. Fourteen lactic acid bacteria were screened for CLA-producing ability using sunflower oil (containing 70% linoleic acid) as a substrate. Among the screened strains, Lactococcus lactis I-01 showed the highest CLA-producing ability. The optimal concentration of sunflower oil for CLA production was 0.1 g/L in whole milk, which accounted for 0.25% of total milk fat. Our results demonstrated that CLA formation in fermented milk could be affected by numerous factors such as bacterial strain, cell number, optimal substrate concentration, and the period of incubation at neutral pH. [source]


    Proteolysis During the Fermentation of Ethanol-Supplemented Miso

    JOURNAL OF FOOD SCIENCE, Issue 8 2001
    R.Y.-Y.
    ABSTRACT: Steam-cooked soybeans mixed with rice koji (2:1, w/w) were ground into a fine paste, combined with NaCl (0 to 12.5%) or sucrose (0 to 25%), and supplemented with 15% ethanol for fermentation. The proteolytic activities decreased with NaCl or sucrose; the dose-response effect of NaCl was much more effective than that of sucrose. When fermented with 15% ethanol and 12.5% sucrose at various moisture contents from 30.6 to 53.0%, proteolysis increased proportionally to the increase of moisture content. Mechanical agitation enhanced proteolysis. After 4 w of fermentation, free amino acid contents were higher in products fermented without pH control than in products fermented with pH control. [source]


    Differential Glucose and Fructose Utilization During Cucumber Juice Fermentation

    JOURNAL OF FOOD SCIENCE, Issue 1 2001
    Z. Lu
    ABSTRACT: Glucose (32 mM) and fructose (36mM) of cucumber juice were degraded simultaneously by Lactobacillus plantarum, but at different rates and extents. Glucose depletion was slightly more rapid than fructose during the exponential growth phase, but slower thereafter and stopped before exhaustion. In contrast, fructose degradation continued until all naturally present fructose was exhausted. When cucumber juice was supplemented with fructose and/or glucose, the starter culture continued to ferment fructose, but not glucose, resulting in an increase in lactic acid production and a decrease in terminal pH. Fructose utilization was not affected by the presence of glucose, but the presence of fructose reduced glucose utilization. [source]


    Fermentation of soybean by Rhizopus promotes the calcium absorption ratio in rats

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2008
    Nakamichi Watanabe
    Abstract BACKGROUND: Soy foods are generally considered to be an unfavourable source of calcium because soybean is rich in phytate, which retards the absorption of calcium. The objective of this study was to assess the effect of dietary fermented soybean, such as tempeh, on calcium absorption in rats. The rats were grouped into three dietary groups and fed the experimental diets for 4 weeks. Soybean, conventional tempeh prepared by aerobic fermentation with Rhizopus (tempeh), and novel tempeh prepared by aerobic and successive anaerobic fermentations (anaerobic tempeh) were used as the protein sources of the experimental diets. RESULTS: The order of the calcium absorption ratio for the 3 days before the end of the test period was as follows: tempeh group > anaerobic tempeh group > soybean group. CONCLUSION: The calcium absorption ratio of the tempeh group in particular was significantly higher than those of the other two groups. The high calcium absorption ratio of the tempeh group might be caused by both low phytate contents and peptides that are produced during the fermentation of soybean by Rhizopus. Copyright © 2008 Society of Chemical Industry [source]


    Effect of fermentation metabolites on rheological and sensory properties of fermented rice noodles

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2008
    Zhan-Hui Lu
    Abstract BACKGROUND: Considering the effect of natural fermentation on the textural improvement of fermented rice noodles in China and South Asia, and given the lack of reports concerning the roles of fermentation metabolites (enzymes, organic acids, glucose and maltose), this study aims to determine fermentation metabolites produced during fermentation of raw milled rice grains, and investigate their effects on rheological and sensory properties of rice noodles. RESULTS: ,-Amylase activity was correlated with reducing sugar content significantly in the supernatant during fermentation process (r = 0.76, P < 0.05). Lactic acid was the dominant organic acid produced by fermentation. Protein and lipid content decreased significantly by fermentation. Treating the rice grains with trypsin, lipase or lactic acid could modify the rheological characteristics and improve the sensory properties of rice noodles. Removal of protein and lipid by physical extraction confirmed the results. The residue of glucose and maltose in rice flour weakened the noodle texture. CONCLUSIONS: Fermentation of raw milled rice decreased protein and lipid content, increased the purity of rice starch, and thus improved the texture of fermented rice noodles. The low molecule weight sugars produced during fermentation should be removed for their negative effect on texture. Copyright © 2008 Society of Chemical Industry [source]


    Application of pure and mixed probiotic lactic acid bacteria and yeast cultures for oat fermentation

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2005
    Associate Professor Dr Angel Angelov
    Abstract Fermentation of a prebiotic containing oat substrate with probiotic lactic acid bacteria and yeast strains is an intriguing approach for the development of new synbiotic functional products. This approach was applied in the present work by using pure and mixed microbial cultures to ferment a heat-treated oat mash. Results show that the strains studied were appropriate for oat fermentation and the process could be completed for 6,10 h depending on the strain. The viable cell counts achieved within this time were above the required levels of 106,107 cfu ml,1 for probiotic products. Both single lactic acid bacteria strains and mixed cultures of the same strains with yeast were found suitable for oat fermentation. However, the pure LAB cultures attributed better flavour and shelf life of the oat drinks. The content of the prebiotic oat component beta-glucan remained within 0.30,0.36% during fermentation and storage of the drinks obtained with each of the strains used. Thus, these products would contribute diet with the valuable functional properties of beta-glucan. Also, the viability of pure and mixed cultures in the oat products was good: levels of cell counts remained above the required numbers for probiotic products throughout the estimated shelf-life period. Copyright © 2005 Society of Chemical Industry [source]