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

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:

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