The Role of Color in Perception of Quality in Fruits and Vegetables

Color is a critical factor in determining the quality of fruits and vegetables, serving as a primary indicator of ripeness and maturity. This visual cue is largely influenced by the pigments present in the produce.

During ripening, the degradation of chlorophyll—the green pigment—reveals the underlying yellow carotenoids in fruits like peaches and yellow apples, signaling readiness for consumption. This transformation is a key aspect of the natural ripening process that consumers associate with freshness and flavor.

However, a similar yellowing in green vegetables, such as broccoli, is often viewed negatively. This discoloration is perceived as a sign of aging or poor quality, despite it being a natural process. The contrast in consumer perception highlights how the desirability of color changes can vary between fruits and vegetables.

Other significant pigments include lycopene, which imparts the rich red color to tomatoes and watermelon, and betacyanins, responsible for the vibrant red and yellow hues in beets. Anthocyanins, found in apples, blueberries, and red cabbage, contribute to a wide spectrum of reds, blues, and purples, enhancing the visual appeal and marketability of these products.

Browning in fruits and vegetables, often seen as an indicator of spoilage, primarily results from an enzymatic reaction triggered by the rupture of cell membranes. This reaction is undesirable as it affects both the appearance and perceived freshness, thereby reducing the product's overall quality in the eyes of consumers.
The Role of Color in Perception of Quality in Fruits and Vegetables

Food Appearance and Color

The fundamental factor influencing the visual characteristics of any food is its color, especially when it is directly associated with other qualities linked to food excellence. This phenomenon is evident in scenarios like the changes that unfold during the ripening of fruits or the decline in color quality as food deteriorates or grows stale.

To elaborate, consider the case of edamame (vegetable soybean). The green color it displays can function as an indicator of freshness, in contrast to the yellow hue that signifies a reduction in freshness. The process of yellowing points to a decrease in the edamame's freshness and is tied to the breakdown of free amino acids, sugars, and ascorbic acid.

The color of food assumes a pivotal role in shaping consumers' initial perceptions of food items. There is a well-established understanding that color stands out as one of the most noticeable visual cues linked to the projected sensory attributes, such as taste and flavor, of the food individuals are on the brink of consuming.

However, relying solely on specifications related to color falls short in capturing the entirety of food appearance. Various factors, such as the caliber of color illumination encompassing factors like brightness, color temperature, fidelity to the actual color, along with the inherent structure of the product, collectively contribute to its appearance.

Furthermore, food colors possess the capacity to convey a range of meanings and thereby give rise to diverse expectations, especially across distinctive age groups and cultures. Genetic divergences, including an individual's sensitivity to taste, can also mold the psychological impact of food color on how flavors are perceived.

Beyond color, there exists a spectrum of additional visual attributes that can be evaluated in food, encompassing dimensions like size, shape, visible surface texture, reflectivity, glossiness, opacity, and translucency.
Food Appearance and Color

Colorimeter

A colorimeter is a device that is used in Colorimetry. It is a light-sensing device that is used to measure the absorbance and transmittance of light as it moves through a sample of liquid. The Hunter is a filter colorimeter which separates the components of reflected color into a three-dimensional color scale.

The colorimeter is usually used to measure the concentration of a known solute in a given solution with the help of the Beer-Lambert law, which postulates that the absorption and concentration of a liquid sample are directly proportional. To analyze color against an existing standard, the colorimeter sends an illuminate through a liquid sample.

The colorimeter was invented in the year 1870 by Louis J Duboscq. In the 1940’s, Richard Hunter introduced a tri-stimulus model, Lab, which is scaled to achieve near uniform spacing of perceived color differences. At that time many scientists involved with color measurement were working on uniform color scales. There were several permutations of the Hunter L, a, b color scale before the current formulas were released in 1966.

The L,a,b color scale views color in a similar manner to which the human eye sees color.
• L scale: Light vs. dark where a low number (0-50) indicates dark and a high number (51-100) indicates light.
• a scale: Red vs. green where a positive number indicates red and a negative number indicates green.
• b scale: Yellow vs. blue where a positive number indicates yellow and a negative number indicates blue.

There are two different types of colorimeters:
- Color densitometers: Measure the density of primary colors.
- Color photometers: Measure color transmission and reflection.

Colorimeters are typically used to compare the results of a new sample to an existing one. Common colorimeter applications include monitoring the growth of a yeast or bacterial culture, assessing beverage color and measuring ink colors.
Colorimeter

Food quality: Color

People accept food on the basis of certain characteristics that they define and perceive with their senses.

Food color has been usually related to the product quality and influences the perception of other attributes such as flavor, sweetness and saltiness. Food color is governed by the chemical, biochemical, microbial and physical changes which occur during growth, maturation, postharvest handling and processing.

Color is the first characteristic that consumers rely on when making food choices, and even the slightest changes can deter a potential buyer and alter the consumer’s perception of product quality.

Color changes are accompanied by undesirable changes in texture, taste, or odor. Overage cheese, beer, meat, and fish all develop off-color, which the consumer recognizes as being associated with poor flavor quality.

Color is one of the most important quality components of fresh fruit and vegetables. Fruit ripening is a complex, genetically programmed process that culminates in dramatic changes in texture, color, flavor and aroma.
Food quality: Color

Food quality: Food appearances

Many experts suggest that investigated consumers most frequently use freshness, taste, and appearance to evaluate food quality. The first impression of a food is usually visual, and a major part of customer willingness to accept a food depends on its appearance.

Appearance of the products including appearance, color, size, and shape. Appearance is determined by physical factors including the size, the shape, the wholeness, the presence of defects (blemishes, bruises, spots, etc.), finish or gloss, and consistency. Size and shape may be influenced by cultivar, maturity, production inputs, and the growing environment.

The most important attribute of any food's appearance is its color, especially when it is directly associated with other food-quality attributes, for example the changes that take place during the ripening of fruit or the loss in color quality as food spoils or becomes stale.

An important problem is discoloration or the fading of the colors of various raw and processed fruits and vegetables. In some cases, color changes are accompanied by undesirable changes in texture, taste, or odor. Overaged cheese, beer, meat, and fish all develop off-color, which the consumer recognizes as being associated with poor flavor quality.

Color plays an essential role in food appearance and acceptability. Synthetic or artificial colors, i.e., coloring agents that are not nature-identical and have been obtained by chemical synthesis, are routinely added to food products to impart desirable sensory characteristics.

Color is derived from the natural pigments in fruits and vegetables, many of which change as the plant proceeds through maturation and ripening. The primary pigments imparting color quality are the fat-soluble chlorophylls (green) and carotenoids (yellow, orange, and red) and the water-soluble anthocyanins (red, blue), flavonoids (yellow), and betalains (red).
Food quality: Food appearances

Color of foods

People associate certain colors with certain flavors, and the color of food can influence the perceived flavor in anything from candy to wine. Consumers perceive that yellow goes with “lemon” and pink goes with “grapefruit.”

Color, a primary indicator of maturity of ripeness, is derived from the pigments found in the product. Loss of the green pigment chlorophyll to unmask yellow carotenoids is a desirable part of the ripening process in many fruits, such as peaches and yellow cultivars of apples.

Red fruits and vegetables are colored by natural plant pigments called “lycopene” or “anthocyanins.” Lycopene in tomatoes, watermelon and pink grapefruit, for example, may help reduce risk of several types of cancer, especially prostate cancer.

Other pigments of important in fruits and vegetables: the red pigment in tomatoes and watermelon: the betacyanins, the red and yellow pigments in beets; and the anthocyanins, the reds, blues, and purples of many fruits and vegetables, including apples, blueberries, and red cabbage. Browning on these products is primarily due to an enzymatic reaction that occurs in response to rupture of the cell membranes.

Green fruits and vegetables are colored by natural plant pigment called “chlorophyll.” Some members of the green group, including spinach and other dark leafy greens, green peppers, peas, cucumber and celery, contain lutein. Lutein works with another chemical, zeaxanthin, found in corn, red peppers, oranges, grapes and egg yolks to help keep eyes healthy.

Color, in a quantitative sense, has been shown to be able to replace sugar and still maintain sweetness perception in flavored foods. It interferes with judgments of flavor intensity and identification and in so doing has been shown to dramatically influence the pleasantness and acceptability of foods.
Color of foods

Color and food acceptability

Color plays a key role in establishing consumer acceptability of food. Of the three sensory properties of foods; food scientists tell that color is more important than flavor and texture in the initial food selection process.

In addition, the colors of food contribute significantly to people to enjoy their meals. For this reason it is desirable to maintain as much of the natural color of fresh and processed foods as possible.

The food processer makes every effort to retain good color characteristics of his/her food products because he or she understands the importance of this property in promoting his/her sales.
Color and food acceptability

Perception of Quality: Color and Texture

Perception of Quality: Color and Texture
Color, a primary indicator of maturity of ripeness, is derived from the pigments found in the product. Loss of the green pigment chlorophyll to unmask yellow carotenoids is a desirable part of the ripening process in many fruits, such as peaches and yellow cultivars of apples. A similar yellowing of green vegetables such as broccoli is considered undesirable. Other pigments of important in fruits and vegetables include lycopene, the red pigment in tomatoes and watermelon: the betacyanins, the red and yellow pigments in beets; and the anthocyanins, the reds, blues, and purples of many fruits and vegetables, including apples, blueberries, and red cabbage. Browning on these products is primarily due to an enzymatic reaction that occurs in response to rupture of the cell membranes.

Texture, like appearance, is evaluated in the context of specific expectations. Crispness and crunchiness are expected in fresh apples, carrots, and celery, but softness or tenderness is desired is asparagus, peas, and plums. The texture of plant products is a consequence of cell wall structure and internal pressure within the cells. Products that maintain structure and turgor during handling and storage remain crisp and may contain an abundance of cell-wall biopolymers. Soft fruits undergo an enzymatic degradation of the cell-wall polysaccharides during ripening. In many fruits, such as peaches and tomatoes, the softening is attributed to pectinolytic enzymes, but cellulose may be important in the ripening of avocadoes. Lignin, a complex biopolymer containing phenolics, can accumulate in cell walls and lead to an objectionable woody texture in products such as asparagus. The mushy texture associated with bruises results from the release, upon rupture of cells, of enzymes that degrade cell-wall polysaccharides, primarily pectin.
Perception of Quality: Color and Texture