Download to read offline
Microbiology of fermented foods ppt.pptx
- 1. CMP Degree College (AConstituent PG College of University of Allahabad) Topic: Microbiology of fermented foods Presented to: Dr.Avinash singh Presented by: Nitesh Kumar Yadav M.Sc. (Botany) III Semester DEPARTMENT OF BOTANY
- 2. Historical Background ofFermentation • Fermentation is one of the oldest food preservation techniques, used for over 8000 years. • Historical records show beer fermentation in Mesopotamia (6000 BC) and bread-making in Egypt (4000 BC). • In India, traditional products like dahi, idli, dosa, gundruk have been fermented for centuries. • Pasteur (1857) first demonstrated that microorganisms were responsible for fermentation, not just chemical processes. • This discovery led to the foundation of industrial microbiology.
- 3. Definition and Importance •Fermentation: Anaerobic breakdown of carbohydrates by microorganisms into simpler end-products like lactic acid, ethanol, CO₂, etc. • Enhances: ◦Shelf-life ◦Nutritional value ◦Digestibility ◦Flavor and texture ◦Safety by inhibiting pathogens • Fermentation is now central in biotechnology, food industry, and probiotic production.
- 4. Types of MicroorganismsInvolved 1.Lactic Acid Bacteria (LAB) ◦Lactobacillus, Leuconostoc, Streptococcus, Pediococcus ◦Produce lactic acid lowers pH preservation → → 2.Yeasts ◦Saccharomyces cerevisiae, Candida spp. ◦Alcoholic fermentation bread, beer, wine → 3.Molds ◦Aspergillus, Rhizopus, Penicillium ◦Break complex molecules using enzymes used in soy and cheese → fermentation 4. Acetic Acid Bacteria: - Acetobacter aceti
- 5. Classification of Fermentation(Based on Product Formed) 1.Lactic Acid Fermentation 2.Alcoholic Fermentation 3.Acetic Acid Fermentation 4.Alkaline Fermentation 5.Mixed (Multiple Microbes) Fermentation
- 6. Lactic Acid Fermentation InvolvesLactic Acid Bacteria (LAB) • Anaerobic process sugars converted into → lactic acid • Lowers pH prevents spoilage → • Examples: Curd, yogurt, kimchi, idli, sauerkraut • Bacteria: Lactobacillus bulgaricus, Streptococcus thermophilus
- 7. Alcoholic Fermentation • Performedby Yeasts, especially Saccharomyces cerevisiae • Sugars ethanol + CO₂ → • Used in wine, beer, bread, toddy • CO₂ helps in leavening bread
- 8. Acetic Acid Fermentation •Conversion of ethanol acetic acid by Acetobacter → aceti • Aerobic process • Used in vinegar production • pH drops to ~3 acts as preservative →
- 9. Alkaline Fermentation • InvolvesBacillus species, produces ammonia, raises pH • Common in fermented legumes, fish • Examples: Natto, kinema, ugba • Microbe: Bacillus subtilis
- 10. Mixed Microbial Fermentation •Multiple microbial groups act together • LAB + Yeasts (e.g., Idli, dosa) • Yeasts + Acetic acid bacteria (e.g., Kombucha) • Molds + Bacteria (e.g., fermented soy) • Complex interactions better flavor, texture, safety →
- 11. Benefits of MicrobialFermentation • Preservation: Organic acids inhibit spoilage/pathogens • Improved Digestibility: Breaks down proteins, starches, fibers • Nutritional Enhancement: B-vitamins, amino acids increase • Health Effects: Probiotic activity improves gut health • Flavor & Aroma: Volatile compounds produced
- 12. Safety and Qualityin Fermentation • Fermentation lowers pH and O₂ inhibits → Clostridium, Salmonella • Starter cultures ensure predictable and safe fermentation • Requires clean equipment and proper time-temperature control • Traditional methods use back-slopping, but industrial methods prefer pure cultures.
- 13. References: Prescott, L. M.,Harley, J. P., & Klein, D. A. (2005). Microbiology (6th ed.). McGraw-Hill. Pelczar, M. J., Chan, E. C. S., & Krieg, N. R. (2001). Microbiology (5th ed.). Tata McGraw-Hill. Frazier, W. C., & Westhoff, D. C. (1995). Food Microbiology (4th ed.). Tata McGraw-Hill. Jay, J. M. et al. (2005). Modern Food Microbiology (7th ed.). Springer. Adams, M. R., & Moss, M. O. (2008). Food Microbiology (3rd ed.). RSC.
- 14.