gets a lot of attention from food product designers, but color often doesn't
get the attention it deserves. For fresh fruits and vegetables, for example,
color is an indication of taste and flavor quality (e.g., freshness, over-ripeness
or under-ripeness), and it is usually the primary attribute consumers
consider in making purchasing decisions. Color measurements are useful
for grading commodities.
association of certain colors with the acceptance of specific types of
foods begins early in childhood development and is maintained throughout
life. The blue-green mold on bread and the off-color of meats, fruits
and vegetables are warning signals that the food may be microbiologically
contaminated, or at least contain off-flavors.
and vegetable processors often base decisions to harvest on color measurements.
Furthermore, measuring the color of various parts of the plant may provide
information that allows farmers to optimize applications of fertilizers
processors also use color measurements to assess the quality of their
products. Measuring the extent of red and brown is a good indicator of
meat freshness, as well as consumer appeal and acceptance.
the color of processed foods can be a critical quality control tool. For
example, the color of extruded cereal and snack products is a good indication
of over- and under-processing conditions. Also, color measurements can
be a useful indicator of the quality of incoming raw materials and ingredients
used to prepare processed foods.
animals eat, but humans feed," says Fergus M. Clydesdale, Ph.D., professor
and department head, Department of Food Science, University of Massachusetts,
Amherst. "Eating is a festive occasion, and color adds to the enjoyment
can dramatically influence the flavor perception of food. Food technologists
often use various colored lights in their tasting sessions to mask the
color of the foods being taste-paneled so tasters will make their acceptability
judgments based on flavor rather than color. One study dramatically illustrates
the influence of color on food acceptability (J. Wheately, "Putting Color
into Marketing," Marketing, October 26, 1973). In this study, panelists
were offered a dinner of steak, peas and french fries abnormally colored
but served under color-masked conditions. Panelists enjoyed the meals
until normal lights were switched on. The appearance of blue steak, red
peas and green french fries was so overwhelmingly objectionable to some
of the panelists that they became ill.
to Clydesdale, studies show that when red color of fruit-flavored products
is enhanced, the perceived sweetness level increases. Food product designers
could potentially reduce sugar and calorie levels in fruit-flavored products
without reducing perceived sweetness by increasing the level of red color
in these products. This phenomenon has been observed in strawberry- and
cherry-flavored beverages containing various levels of red color. Other
colors also have been observed to affect sweetness perception, depending
on the appropriate combination of color, flavor and sucrose.
addition, Clydesdale (in "Color as a Factor in Food Choice," Critical
Reviews in Food Science and Nutrition, 33(1): 83-101, 1993) reports that
color affects taste thresholds. Studies indicate that the threshold concentrations
at which the basic tastes (salt, sour, bitter and sweet) are perceived
are color dependent. In the study, the effects of red, green and yellow
on the threshold concentrations of sweet, sour, salty and bitter tastes
were measured. The yellow-colored sweet solution was detected at a significantly
higher concentration than the colorless control. Therefore, tasters did
not associate yellow color with a sweet taste. However, the green-colored
sweet solution was detectable at a concentration significantly below that
of the control.
sour solutions, the red-colored sour solution was detected at a slightly
higher concentration than the colorless control sour solution. However,
the sour flavor in yellow and green solutions was detected at significantly
higher concentrations than in the control.
salt solutions, color had little influence on the perception of saltiness.
However, with the bitter solutions, yellow and green solutions were detected
at significantly higher concentration than the colorless bitter control,
but the red bitter solutions required the highest concentrations before
they were detected.
potentially useful application of color manipulation is with foods for
the elderly. After age 40 the senses of smell and taste tend to deteriorate.
Clydesdale says that paying more attention to color can help food processors
compensate for the loss of taste perception and significantly improve
the appeal of foods to the elderly. Food processors' interest in this
area of color application is likely to escalate since the average age
of consumers is rapidly increasing as the massive baby boom generation
ages. Clydesdale has recently initiated a study to determine if color
affects mouthfeel perception of foods.