FERMENTATION AND PICKLING

Fermentation

Basics of Fermentation

• Definition: Fermentation is the use of biological processes to create products, utilized for many centuries in food production and preservation.

• Key Characteristics:

  • Involves microorganisms (bacteria and yeast) breaking down food substances chemically.

  • Major uses:

  • Food Production: Creating new food forms.

  • Food Preservation: Extending shelf life.

  • Technical Process: Converts carbohydrates (sugars and starches) into alcohol or organic acids.

  • Function of Byproducts: The acids or alcohols act as natural preservatives by preventing the growth of harmful bacteria and imparting distinct flavors (zest, tartness) to fermented foods.

Types of Fermentation in Foods

1. Alcoholic Fermentation

   • Substrates: Sugars

   • Products: Ethanol + CO₂

   • Microbe: Yeast (Saccharomyces)

   • Examples: Tapuy, Rice Wine, Beer

2. Lactic Acid Fermentation

   • Substrates: Sugars

   • Products: Lactic Acid

   • Microbe: Lactic Acid Bacteria

   • Examples: Atchara, Kimchi, Yogurt, Bagoong

3. Acetic Acid Fermentation

   • Substrates: Ethanol

   • Products: Acetic Acid

   • Microbe: Acetobacter

   • Examples: Vinegar, Sukang Iloko

4. Mixed Fermentation

   • Description: Combination of multiple processes.

   • Examples: Traditional Bagoong, Fermented Rice

5. Proteolytic Fermentation

   • Substrates: Proteins

   • Products: Amino Acids

   • Microbe: Halophilic Bacteria

   • Examples: Bagoong, Patis

Detailed Process of Different Fermentations

1. Alcoholic Fermentation

   • Process:

     • Two-step process where yeast first converts glucose to pyruvate (glycolysis) and then to alcohol under anaerobic conditions.

   • Overall Equation:
     $C<em>6H</em>{12}O<em>6 ightarrow 2 C</em>2H<em>5OH + 2 CO</em>2$

   • Microbe: Yeast, primarily Saccharomyces cerevisiae; variants used include Saccharomyces pastorianus for lager beer and Saccharomyces bayanus for wines.

2. Lactic Acid Fermentation (The “Sour” Pathway)

   • Homolactic Fermentation:

     • Produces predominantly lactic acid (over 90%); no gas produced.

     • Key Microbes: Lactobacillus acidophilus, Lactobacillus bulgaricus, Streptococcus thermophilus, Pediococcus.

   • Heterolactic Fermentation:

     • Produces lactic acid, ethanol, acetic acid, and CO₂.

     • Key Microbes: Leuconostoc mesenteroides, Lactobacillus brevis, Lactobacillus fermentum.

3. Acetic Acid Fermentation

   • Process:

     • Requires oxygen; oxidation of ethanol to acetic acid.

   • Overall Equation:
     $C<em>2H</em>5OH + O<em>2 ightarrow C</em>2H<em>4O</em>2 + H_2O$

   • Microbes:

     • Acetobacter aceti (most common for vinegar).

4. Proteolytic Fermentation

   • Mechanism: Enzymes (proteases) break down proteins releasing free amino acids ( glutamate triggers umami flavor).

   • Microbe: Halophilic bacteria which thrive in high salt conditions, e.g., Halobacterium spp., Tetragenococcus halophilus, Bacillus spp..

Summary Comparison of Types of Fermentation

Importance of Fermentation

1. Preservation:

   • The "Hurdle" Strategy: Ancient cooks used fermentation to create barriers against pathogens by lowering pH in products like Atchara or Sukang Iloko to inhibit Clostridium botulinum growth.

   • Salinity & Osmosis: In Bagoong, high salt draws out moisture, creating an environment that only halophilic bacteria can thrive.

   • Alcohol: Tapuy's alcohol content (10-15%) helped sterilize liquids, rendering them safer than stagnant water.

2. Enhanced Nutrition:

   • Breaking Down Anti-nutrients: Fermentation helps release minerals from grains, legumes, and seeds which would typically be locked by compounds like phytic acid.

   • Vitamin Synthesis: Certain bacteria in fermented foods synthesize B vitamins, enhancing nutrient availability, especially in protein-scarce regions.

   • Detoxification: Traditional fermentation can neutralize naturally occurring toxins in raw products (e.g., cassava).

3. Complex Flavors:

   • Through proteolytic fermentation, amino acids release glutamate leading to umami.

   • Potent fermented foods (e.g., Bagoong, Patis) showcase a flavor economy where small amounts can enhance large meals significantly.

   • Fermentation was also an early zero waste practice, repurposing unused food parts.

Pickling

Definition and Basics

• Pickling: The preservation of food via anaerobic fermentation in brine or immersion in vinegar, creating a high-acid environment (low pH) to inhibit spoilage bacteria.

• Methods:

  1. Fermented Pickles (Slow/Brine Method)

  2. Quick Pickles (Fast/Vinegar Method)

1. Fermented Pickles (Brine Method)

• Key Solution: Saltwater or brine solution.

• Process: Vegetables submerged in brine; salt eliminates harmful bacteria while allowing lactic acid bacteria to flourish, producing lactic acid as a byproduct.

• Result: Tangy, complex flavors that develop over time, and nutrition benefits from probiotics due to the absence of heat.

2. Quick Pickles (Vinegar Method)

• Key Solution: Vinegar solution (usually hot).

• Process: Vinegar, salt, and sugar mixed and poured over vegetables for immediate preservation; no fermentation required.

• Result: Sharp and crisp flavor, sterile with no probiotics; can be shelf-stable if canned.

Summary Comparison of Pickling Methods

Salt Percentage for Pickling

Step-by-Step Procedure for Making Fermented Cucumbers

1. Weigh the empty jar (e.g., 500g).

2. Pack the jar with cucumbers, garlic, dill, and water until covered.

3. Weigh the full jar (e.g., 1500g).

4. Calculate total ingredients: 1500g (full) - 500g (empty) = 1000g.

5. Calculate salt: 1000g x 0.035 (3.5%) = 35g salt.

6. Dissolve salt in some water and pour back in.

Important Concepts in Fermentation and Pickling

Grain Strength

• Definition: Measurement of acetic acid content in vinegar.

• Relationship: 1% acetic acid = 10 Grain (e.g., 5% acetic acid = 50 Grain).

Common Problems Encountered in Fermentation and Pickling

1. Temperature Issues:

   • Cool temperatures lead to sluggish fermentation.

   • High temperatures can damage yeast, promoting spoilage.

2. Excess Sugar: High sugar concentration adversely affects fermentation.

3. Nutrient Deficiencies: Sufficient nutrients (minerals) are crucial for optimal yeast performance.

4. Distilled Water: Lacks minerals and oxygen, negatively impacting yeast reproduction.