Transformation of citric acid to acetic acid, acetoin and diacetyl by wine making lactic acid bacteria.

<p style="text-align: justify;">Acetic acid and lactic acid bacteria were present at all stages of wine making. A lower pH and a highter ethanol concentration limit the risks of alteration. During the conservation, a low temperature, good use of S0<sub>2</sub> and frequent checkings ensure control of bacterial growth and metabolism.</p>

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Interesting Starter Culture Strains for Controlled Cocoa Bean Fermentation Revealed by Simulated Cocoa Pulp Fermentations of Cocoa-Specific Lactic Acid Bacteria

Applied and Environmental Microbiology ◽

10.1128/aem.00594-11 ◽

2011 ◽

Vol 77 (18) ◽

pp. 6694-6698 ◽

Cited By ~ 33

Author(s):

Timothy Lefeber ◽

Maarten Janssens ◽

Frédéric Moens ◽

William Gobert ◽

Luc De Vuyst

Keyword(s):

Acetic Acid ◽

Lactic Acid ◽

Citric Acid ◽

Lactic Acid Bacteria ◽

Starter Culture ◽

Lactobacillus Fermentum ◽

Cocoa Bean ◽

Bacterial Strains ◽

Content Type ◽

Cocoa Bean Fermentation

ABSTRACTAmong various lactic acid bacterial strains tested, cocoa-specific strains ofLactobacillus fermentumwere best adapted to the cocoa pulp ecosystem. They fermented glucose to lactic acid and acetic acid, reduced fructose to mannitol, and converted citric acid into lactic acid and 2,3-butanediol.

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Fermentation quality and aerobic stability of Napier grass ensiled with citric acid residue and lactic acid bacteria

Tropical Grasslands - Forrajes Tropicales ◽

10.17138/tgft(9)52-59 ◽

2021 ◽

Vol 9 (1) ◽

pp. 52-59

Author(s):

Xuxiong Tao ◽

Chongwen Ji ◽

Sifan Chen ◽

Jie Zhao ◽

Siran Wang ◽

...

Keyword(s):

Acetic Acid ◽

Lactic Acid ◽

Citric Acid ◽

Lactic Acid Bacteria ◽

Water Soluble ◽

Neutral Detergent Fiber ◽

Napier Grass ◽

Pennisetum Purpureum ◽

Aerobic Stability ◽

Fermentation Quality

This study was conducted to investigate the effects of adding citric acid residue (CAR) with or without lactic acid bacteria (LAB) to Napier grass (Cenchrus purpureus; syn. Pennisetum purpureum) cv. Sumu No. 2 at ensiling on the fermentation quality and aerobic stability of the resulting silage. Treatments included: Control (Napier grass forage without additives); and Napier grass inoculated with lactic acid bacteria (Lactobacillus plantarum and L. buchneri) at 1 × 106 cfu/gfresh weight (FW) forage (LAB) or 36 g citric acid residue/kg FW forage (CAR) or a mixture of CAR and LAB (CL). Forty-five days after ensiling the silages were tested for chemical and microbial composition and an aerobic stability test was conducted. The addition of CAR with or without LAB increased the DM and lactic acid concentrations in silage and decreased pH plus acetic acid, ammonia nitrogen (NH3-N), neutral detergent fiber and cellulose concentrations relative to Control. The pH in LAB silage was lower than in Control, while lactic acid concentration was higher. During the first 2 days of aerobic exposure, all additives increased the water-soluble carbohydrate (WSC) and lactic acid concentrations and decreased pH plus NH3-N and acetic acid concentrations. Moreover, CL silages had the highest WSC and the lowest NH3-N and acetic acid concentrations during aerobic exposure. However, all additives failed to improve the aerobic stability of the silage. While CAR with or without LAB inoculant improved the fermentation quality of silage made from Napier grass, more studies are warranted to identify additives which can improve aerobic stability of the silage after opening.

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Kinetic Analysis of Strains of Lactic Acid Bacteria and Acetic Acid Bacteria in Cocoa Pulp Simulation Media toward Development of a Starter Culture for Cocoa Bean Fermentation

Applied and Environmental Microbiology ◽

10.1128/aem.01206-10 ◽

2010 ◽

Vol 76 (23) ◽

pp. 7708-7716 ◽

Cited By ~ 64

Author(s):

Timothy Lefeber ◽

Maarten Janssens ◽

Nicholas Camu ◽

Luc De Vuyst

Keyword(s):

Acetic Acid ◽

Lactic Acid ◽

Citric Acid ◽

Lactic Acid Bacteria ◽

Starter Culture ◽

Acetic Acid Bacteria ◽

Cocoa Bean ◽

Cocoa Bean Fermentation ◽

Acid Tolerant ◽

Species Specific

ABSTRACT The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.

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Effect of pH, Acidulant, Time, and Temperature on the Growth and Survival of Listeria monocytogenes

Journal of Food Protection ◽

10.4315/0362-028x-52.8.571 ◽

1989 ◽

Vol 52 (8) ◽

pp. 571-573 ◽

Cited By ~ 116

Author(s):

KENT M. SORRELLS ◽

DAVIN C. ENIGL ◽

JOHN R. HATFIELD

Keyword(s):

Antimicrobial Activity ◽

Acetic Acid ◽

Lactic Acid ◽

Listeria Monocytogenes ◽

Citric Acid ◽

Hydrochloric Acid ◽

Malic Acid ◽

Incubation Temperature ◽

Growth And Survival ◽

Ph Values

The effect of different acids, pH, incubation time, and incubation temperature on the growth and survival of four strains of Listeria monocytogenes in tryptic soy broth was compared. Hydrochloric acid (HCl), acetic acid (AA), lactic acid (LA), malic acid (MA), and citric acid (CA) were used to acidify tryptic soy broth to pH values 4.4, 4.6, 4.8, 5.0, and 5.2 pH. Incubation times were 1, 3, 7, 14, and 28 d at 10, 25, and 35°C. The inhibition of L. monocytogenes in the presence of high acidity appears to be a function of acid and incubation temperature. Based on equal pH values, the antimicrobial activity is AA > LA > CA ≥ MA > HCl at all incubation times and temperatures. When based on equal molar concentration, the activity appeared to be CA ≥ MA > LA ≥ AA > HCl at 35 and 25°C, and MA > CA > AA ≥ LA > HCl at 10°C. Greatest antimicrobial activity occurred at 35°C. Greatest survival occurred at 10°C and greatest growth occurred at 25°C. Final pH of the medium was as low as 3.8 in HCl at 28 d. All strains grew well at pH values lower than the minimum previously reported (5.5–5.6).

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Microbiological and Physicochemical Characterization of Small-Scale Cocoa Fermentations and Screening of Yeast and Bacterial Strains To Develop a Defined Starter Culture

Applied and Environmental Microbiology ◽

10.1128/aem.01144-12 ◽

2012 ◽

Vol 78 (15) ◽

pp. 5395-5405 ◽

Cited By ~ 86

Author(s):

Gilberto Vinícius de Melo Pereira ◽

Maria Gabriela da Cruz Pedrozo Miguel ◽

Cíntia Lacerda Ramos ◽

Rosane Freitas Schwan

Keyword(s):

Acetic Acid ◽

Lactic Acid ◽

Citric Acid ◽

Dominant Species ◽

Starter Culture ◽

Physicochemical Characterization ◽

Cocoa Bean ◽

Small Scale ◽

Content Type ◽

Cocoa Bean Fermentation

ABSTRACTSpontaneous cocoa bean fermentations performed under bench- and pilot-scale conditions were studied using an integrated microbiological approach with culture-dependent and culture-independent techniques, as well as analyses of target metabolites from both cocoa pulp and cotyledons. Both fermentation ecosystems reached equilibrium through a two-phase process, starting with the simultaneous growth of the yeasts (withSaccharomyces cerevisiaeas the dominant species) and lactic acid bacteria (LAB) (Lactobacillus fermentumandLactobacillus plantarumwere the dominant species), which were gradually replaced by the acetic acid bacteria (AAB) (Acetobacter tropicaliswas the dominant species). In both processes, a sequence of substrate consumption (sucrose, glucose, fructose, and citric acid) and metabolite production kinetics (ethanol, lactic acid, and acetic acid) similar to that of previous, larger-scale fermentation experiments was observed. The technological potential of yeast, LAB, and AAB isolates was evaluated using a polyphasic study that included the measurement of stress-tolerant growth and fermentation kinetic parameters in cocoa pulp media. Overall, strainsL. fermentumUFLA CHBE8.12 (citric acid fermenting, lactic acid producing, and tolerant to heat, acid, lactic acid, and ethanol),S. cerevisiaeUFLA CHYC7.04 (ethanol producing and tolerant to acid, heat, and ethanol), andAcetobacter tropicalisUFLA CHBE16.01 (ethanol and lactic acid oxidizing, acetic acid producing, and tolerant to acid, heat, acetic acid, and ethanol) were selected to form a cocktail starter culture that should lead to better-controlled and more-reliable cocoa bean fermentation processes.

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