Brining and Fermentation Overview

Advantages of Brining and Acid Fermentation

• Preserves food by resisting microbial spoilage and toxin development between harvest and consumption
• Reduces the likelihood of pathogenic microorganisms
• Modifies flavor and improves nutritional value

Brining and Fermentation Principles

• Salt draws water and nutrients from fruits and vegetables, creating a substrate for lactic acid bacteria.
• Salt and fermentation acids inhibit undesirable bacteria and prevent softening.

Microorganisms Involved

• Primarily lactic acid bacteria
  • Leuconostoc mesenteroides (heterofermentative)
  • Lactobacillus plantarum (homofermentative)

Fermented Fruits and Vegetables Products

• Pickles
• Kimchi
• Fermented green mango

Pickle (Specifics)

• Food preserved in vinegar, brine or similar solutions. Often refers to pickled cucumbers
• Preserved with or without fermentation
• Originates from the Dutch word pekel (brine)
• Popular due to flavor and improved nutritional value (especially B vitamins)
• Fruit and vegetables may undergo a preliminary brine fermentation before pickling solution addition
• Varying sugar content in fruits and vegetables results in varying lactate amounts during fermentation.

Types of Pickles

• Salt or Salt-Stock Pickles

  • Preparation involves salting
    • Dry Salting Method: Two stages using the same recipe.
    • Wet Salting Method: Place cucumbers in brine (10.6% salt). Check solution strength after 3 days. Maintain concentration by adding salt and weighting on top.

• Dill Pickles

Methods of Fermentation

• Traditional Fermentation: Typically takes 6-9 months.
• Salt-tolerant bacteria may initially grow in brine.
• Controlled Fermentation: Minimizes the common defects associated with traditional methods.

Dill Pickles (Specifics)

• Flavored with dill and often additional spices.
• May be unfermented or fermented.
• Lower salt concentration compared to salt-stock pickles.
• Acidity comes from added vinegar; can be unfermented, fermented, or made from salt-stock pickles.
• Brine is acidified.

Dill Pickle Nutrition

• High in sodium (350-500 mg per spear).
• Varying sodium content depending on the type (sour vs. sweet).

Microbial Changes

• Salt-tolerant bacteria (like Pseudomonas, Flavobacterium, Achromobacter, Bacillus) initially grow in brine.
• At lower salt concentrations, Leuconostoc, S. faecalis, and Pediococcus increase acidity.
• L. plantarum often becomes the dominant fermentation microorganism in brines.

Biochemical Changes

• pH decreases during fermentation (typically to 4.6 or lower).
• Acidity increases due to lactic acid production (up to 1.2-1.5%).
• Increased acidity inhibits more spoilage microorganisms.
• Potential for yeast growth in certain situations; yeasts further ferment sugars to alcohol or carbon dioxide.
• Film yeasts can cause spoilage.

Commercial Production (Process)

• Cucumber is washed and sanitized.
• Acidified with acetic acid (glacial acetic acid).
• Purged with nitrogen.
• Sodium acetate is added.
• Incubated (10-24h) and inoculated.
• Fermentation (10-14 days) with nitrogen purging and additional salt.
• Additional steps for packaged production: Cutting cucumbers, arranging in jars, pouring pickling solution, draining, pasteurizing solution and sealing jars.