Fermentation defects — When fructose is converted to mannitol by contaminating microbes, the defect is commonly termed:

Microbiology Wine and Beer Difficulty: Easy
Choose an option
  • A
    mannkic
  • B
    mannitic
  • C
    amertume
  • D
    none of these

Answer

Correct Answer: mannitic

Explanation

Introduction / Context:Mannitol fermentation defects appear in dairy and vegetable fermentations when certain heterofermentative bacteria reduce fructose to mannitol. This shifts sweetness, alters osmotic balance, and can co-occur with gas production, impacting texture and flavor expectations of the finished product.

Given Data / Assumptions:

  • Defect involves fructose reduction to the polyol mannitol.
  • Microbial culprits often include Leuconostoc and some Lactobacillus spp.
  • Terminology distinguishes among different spoilage phenomena.

Concept / Approach:The correct descriptive term is “mannitic fermentation,” referring to mannitol formation. “Amertume” denotes bitterness defects; “mannkic” is a misspelling and not a recognized term. Recognizing mannitic defects guides choice of starter cultures, sugar profiles, and temperature to suppress unwanted pathways.

Step-by-Step Solution:

Identify fructose → mannitol conversion as the core biochemical change.Select the standardized descriptor “mannitic.”Exclude unrelated or misspelled terms.

Verification / Alternative check:Fermentation handbooks use “mannitic fermentation” to describe off-traits, sometimes with gassiness and altered acidity profiles in pickles and certain cheeses.

Why Other Options Are Wrong:

  • Mannkic: not a standard term; likely a typographical error.
  • Amertume: indicates bitterness, not mannitol formation.
  • None of these: incorrect because “mannitic” is the accepted term.

Common Pitfalls:Confusing mannitol-related sweetness with lactate-derived sourness; both can coexist but arise from different pathways.

Final Answer:mannitic

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