The influence of color on food acceptance

In spite of the numerous ways by which the appearance attributes of food affect consumer acceptance, the majority of research on the role of appearance in food acceptance has focused on the influence of color.

Color is an important property of foods that adds to enjoyment of eating. 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.

On study showed that when jellies were colored in an atypical manner, the fruit flavors were incorrectly identified.  It appears that color references for foods are the result of experience, culture and conditioning.

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 variations in foods throughout the seasons and the effect of food processing and storage often require that manufacturers add color to certain foods to meet consumer expectations. The general principles for the application of colors to products are described with the overall aim of matching what the consumer expects from the particular food product.

Account must be taken of the effects of pH and processing, especially browning from the Maillard reaction and loss of initial color.
The influence of color on food acceptance

Carotenoid pigments as food colorants

Many colorants are natural and these include the yellow, from the annatto seed; green form chlorophyll; orange from carotene; brown form burnt sugar; and red from beets tomatoes and the cochineal insect. 

The carotenoids, particularly their nature-identical synthetic counter parts, beta-app-8’-carotenal,beta-carotene and canthaxanthin, are popular food colorants.

Carotenoids are classified as oil soluble but most foods require water soluble colorants; thus their approaches were used to provide water dispersible preparations. Carotenoids colorants are appropriate for a wide variety of foods.

The carotenoids add yellow, red and orange pigmentation to foods. Beta-carotene and beta-apo-8’-carotenal have vitamin activity but canthaxanthin does not.

Federal regulations permit addition of beta-carotene to foods at any concentration but specify maximum limits fro beta-app-8’ carotenal (1.5 mg/lb or pinto food).

Beta-carotene is used to colour margarine, shortening, butter, cheese, baked goods, confections, ice cream, egg nog, macaroni products, soups, juices, pudding and beverages. Beta-carotene has good tinctorial strength fair light stability, poor oxidation stability and good pH stability.

Beta-apo-8’-carotenal may be used to colour juices, fruit drink, soups, jams, jellies, gelatine, processed cheese, margarine, sale dressing and fats and oils.
Carotenoid pigments as food colorants

What are betalains?

Betalains are a group of pigments found in red beet and to some extent, in cactus fruits, pokeberries and a number of flowers (bougainvillea). More than 50 naturally occurring betalains are known.

The pigments are red and yellow and resemble the anthocyanins and flavonoids in an appearance. However the betalains contain nitrogen.
 
As with anthocyanin, betalains are present in flowers or fruits and may play a role as attractants for vectors in the pollination process and in seeds dispersal by animals.

Basic structure of betalains

The term ‘betalains’ was introduced by Mabry and Dreiding in 1968. They are immonium derivatives of betalamic acid.

Betalains have been proposed as a defense mechanism because they are accumulated when tissues are injured. Moreover, their appearance occurs in association with antifungal proteins in some plants.

The betalains are stable in the pH range 4-6 and they are subject to degradation by thermal processing as in canning.

Within these limitations, betalains are ideally used to color products have a short shelf life, are packaged to reduce exposure to light, oxygen and high humidity, do not received extended or high heat treatment and are marketed in the dry state.

Despite these limitations, betalains have been suggested for coloring ice cream, yoghurt, cake, mixes, gelatin, desserts, meat substitutes, gravies, frostings and many others.
What are betalains?

What is anthocyanidin?

When the sugar moiety of an anthocyanin is hydrolyzed, the aglycone (non-sugar hydrolysis product) is referred to as an anthocyanidin.

The color of anthocyanins and anthocyanidins results from excitation of molecule by visible light. At pH values lower than 3, the anthocyanidin appears as the red flavylium cation, and at pH values higher than 6 it is preset as the blue quinonoidal base form.

The richest sources of anthocyanidins to the diet are red wine and fruit, particularly berries. Foods can have one or a variety of anthocyanidins and the concentration is influenced by environmental conditions, ripeness, cultivar, cultivation site, processing and storage.

Only three types of anthocyanidins have been identified in plant tissues. Pelargonidin, cyanidin and delphinidin are wide spread in nature with cyanidin the most common.

Cyanidin is the anthocyanidin found in red cabbage, pelargonidin occurs in radishes and red-seeded varieties of bean and delphinidin occurs in aubergines.

Anthocyanidins are less water soluble than their corresponding glycosides (anthocyanins) and they are not found free in nature.

Freezing may be the best method of preserving anthocyanidins in foods so as the consumption can continue throughout the year even when particular foods such as berries are not in season.
What is anthocyanidin?

Color of Food

Color of Food
Color is important to many food, both those that are unprocessed and those that are manufactured.

Together with flavor and texture, color plays an important role in food acceptability.

In addition, color may provide an indication of chemical changes in a food, such as browning and caramelization.

For a few clear liquid foods, such as oils and beverages, color is mainly a matter of transmission of light.

Other foods are opaque - they derive their color mostly from reflection.

Some hues occur frequently in foods provided by nature. Green, red, pink, orange, yellow and purple are common. Blue green is rare and no blues exist at all.

It is instructive to consider the fundamental natural rules governing the colors of the world around us and the food we eat.

Color is the general name for all sensations arising from the activity of the retina of the eye. When light reaches the retina, the eye’s neural mechanism responds, signaling color among other things.

Light is the radiant energy in t wavelength range of about 400 to 800 nm. According to this definition color cannot be studied without considering the human sensory system.

The color perceived when the eye views an illuminated object is related to the following three factors: the spectral composition of the light source, the chemical and physical characteristics of the object and the spectral sensitivity properties of the eye.

To evaluate the properties of the object we must standardize the other two factors. Fortunately, the characteristics of different people’s eyes for viewing colors are fairly uniform; it is not too difficult to replace the eye by some instrumental sensor or photocell that can provide consistent results.

There are several systems of color classification; the most important is the CIE system (Commission International de I’Eclairage –International Commission on Illumination. Other systems used to describe food color are the Munsell, Hunter and Lovibond systems.

Added colorants in foods dates from at least 3,700 BC when Egyptians were coloring their candy.

Sugar imported into Europe from Alexandra in the twelfth century was colored with madder and kermes, but the use of cochineal probably predates this.

Awareness of browning would have predated the use of color additives. For an extended shelf life in fresh fruits and vegetables, enzymatic browning must be eliminated.

Foods depending on enzymatic browning for their quality include black tea, dates, prunes and raisin, Non enzymatic browning provides many of the flavors of baking and cooking.
Color of Food