Lists of ice cream “defects” often include some
characteristics that can be positive or negative, depending on the context.
Such terms would be considered as defects only when they are not appropriate to
the target flavor profile of a specific product. On the other hand, many
descriptive terms are unequivocally defects that detract from quality whenever
they are detected. Both types will be described briefly below, broadly
organized as to their source. When appropriate, a brief reference to causative
factors will be included.
- Added flavorings: lacks fine flavor—flavor profile
falls short of target or is not “balanced”); wrong flavor—incorrect flavoring
used; excessive, deficient, unnatural, atypical of designated flavor; foreign
flavor—flavor profile alien to the flavor descriptor.
- Sweeteners: syrup—similar to Karo syrup, from
high corn syrup solids levels or corn syrup solids that have deteriorated due
to excessive age or exposure to high temperature; excessive, deficient,
unnatural.
- Dairy ingredients: whey flavor—like graham
crackers or aroma of alfalfa hay, from high levels or poor quality of whey
solids; salty—high levels of MSNF/whey solids or (rarely) added sodium
chloride; lacks freshness/old ingredient—stale characteristics associated with
old dairy components; rancid—like grated cheese, caused by hydrolysis of milk
fat; oxidized—so-called “cardboard” flavor, produced by the oxidation of milk
fat in dairy ingredients or the ice cream itself (most often due to exposure to
ultraviolet light); fermented/acid (tart)—flavor profile similar to that of
cultured dairy products, caused by growth of lactic acid organisms;
unclean/bitter/putrid—general unpleasant flavor and/or aftertaste, caused by
the growth of psychrotrophic microorganisms.
- Processing (mix or dairy ingredients):
cooked—milk custard character, caused by high heat treatment; burnt—an extreme
cooked character, resulting from very high temperature exposure or multiple
high heat exposures.
- External: characteristics resulting from
chemical, physical, or microbiological contamination can include, but are not
limited to, contamination by cleaning/sanitizing chemicals, contamination of
added flavors or flavorings themselves and the like; inclusions can contribute
to flavor defects either through poor quality per se or deterioration through
prolonged storage.
The direct perception of flavor involves two elements: taste (sweet, salty,
sour, bitter sour, and, most recently, umami/savory), which is perceived by
taste buds in the mouth; and aroma, which is detected by odor perceptors in the
nasal passage. The nature of flavor can be influenced by other sensory
characteristics, such as body and texture. For example, the presence of ice can
anesthetize the taste buds temporarily to an extent that depends upon the
amount of ice and the size of the particles. Also, the viscosity of the product
after it melts can interfere with the vaporization of aroma components and slow
their passage to the aroma perceptors, a phenomenon referred to as “flavor
masking.” When considering flavor profiles that seem to lack a particular
flavor element or show an uncharacteristic balance, it is important to
understand that such situations may result from a masking of a flavor profile
rather than an error in the type or level of flavoring added.
The inclusion of effective sensory evaluation in an ice cream quality assurance
program—i.e., the capability to identify flavor attributes that fall short of
expectation and identifying their sources—is a critical element to the
retention of positive attributes and the avoidance of negative influences (true
defects). Once shortcomings and their sources are known, corrective action can
be applied to ensure success in the marketplace.
