*5.3.3 Application of cochineal in food coloration*

Carmine has a color that is similar to cured pork [82]. Cochineal-derived colors are commonly found in alcoholic beverages, yoghurts, juices, ice creams, and confectionary, but they can also be found in jams and some processed meat items [83]. Typical applications of carmine dye in food are sausages and salami displaying an intense red color [84].

## *5.3.3.1 Color produced*

Cochineal produces intense purple color and the scarlet red color is obtained on complexing with aluminum.

#### *5.3.3.2 Extraction & application conditions*

For foodstuffs, extraction conditions for cochineal/carminic acid generally involve acid and/or enzymatic hydrolysis with or without solid-phase extraction (SPE). Carminic acid from cochineal is precipitated onto an alumina hydrate substrate. The precipitated complex called carmine is dried, grounded, and used as a food colorant. Though insoluble in water, carmine can be rendered water-soluble by reaction with a strong alkali. The color of carmine is dependent on the pH; at pH–4 and below, it is orange in color; as pH increases, it becomes redder and bluer until it becomes purplish-red above pH–6.5. The color pigment shows excellent heat and light stability.

#### *5.3.3.3 Functional properties related to food application*

Although carminic acid does not produce any genotoxic or cytotoxic effects, it has been related to cause anaphylactic reactions, asthma, urticaria, and angioedema in many individuals.

#### *5.3.3.4 Case study-11*

Surimi, minced beef, and milk were colored with naturally occurring carminic acid to change their color. Color modulation of carminic acid and carminic aluminum lake colored surimi, minced meat, and milk through the addition of different food additives, proteins, and metal ions was assessed [85]. Carminic acid rendered a light purple color to surimi while carminic aluminum lake rendered a magenta

*Colorimetric Measurement and Functional Analysis of Selective Natural Colorants… DOI: http://dx.doi.org/10.5772/intechopen.102473*

color. Minced meat and milk turned red and gray-green respectively with carminic acid. Iron and copper changed the color of the samples significantly. Changes were also observed in the case of the presence of food additives. The presence of myofibrillar protein, whey protein isolates, and soy protein isolate changed the pH of the medium resulting in a red color. Sodium nitrite is used as a preservative in the meat industry and as a chromogenic agent as well. Carminic acid changed to yellow with the addition of sodium nitrite though no change was observed in the case of the carminic aluminum lake. Also, no change in color was observed for ascorbic acid. Due to the chelation of the dye in presence of calcium ions, the color of the foodstuff changed. Hence, this dye was not found suitable for food samples rich in calcium and iron.

#### **Figure 2.**

*UV–vis curves in the visible range with λmax values of aqueous extracts, and chemical structures of the coloring pigments present in the source of different natural colors.*


**Table 12.**

*Determination of carminic acid in strawberry-flavored milk and candy using differential pulse polarography and UV–visible spectrophotometry.*

#### *5.3.3.5 Case study-12*

Pulse polarography was used to quantify carmine food dye in strawberryflavored milk and candies and the results were compared with the UV–visible spectrophotometric analysis [77]. A pH 2.0 Britton-Robinson (B-R) buffer solution was used to perform differential pulse polarography on a falling mercury electrode (peak at 489 mV). Strawberry flavored milk and candy samples were added into the polarographic cell containing B-R buffer (pH 2.0) and polarograms were taken. The concentrations were measured using the standard addition method. To compare the validity of this electroanalytical method, the samples were analyzed using UV– visible spectrophotometry (**Figure 2**). The relationship between the peak current and carminic acid concentration was linear in the range of 1 μM to 90 μM with a detection limit of 0.16 μM. The results of both methods showed similar accuracy and precision. The pulse polarographic method was advantageous as it showcased high sensitivity, low limit of determination, simple instrumentation, and easy operation (**Table 12**). The UV-vis curves with the peak of maximum absorbance of turmeric [7], annatto [41] and cochineal [75] along with chemical structures of the main coloring component present in turmeric [9], annatto [50] and cochineal [58] are given in **Figure 2**.

#### **6. Conclusion**

With the introduction of synthetic dyes like aniline, alizarin, and indigo in the mid-1800, natural dyes lost their economic and commercial significance. Synthetic dyes now dominate the market due to their wide range of colors, ease of production, and excellent fastness features. Existing limitations and technical problems in the procurement of natural dyes have further compelled the shifting of focus from natural dyes to synthetic dyes. However, within a period of 150 years, some serious drawbacks associated with synthetic dyes have come to light; synthetic dyes are suspected to release harmful chemicals that are allergic, carcinogenic, and detrimental to human health. The use of eco-friendly natural dyes that are fairly nonpolluting, automatically harmonizing, more challenging, and have rare color ideas in textile and food applications is now becoming increasingly popular due to the strict environmental requirements set on the harmful chemicals used in synthetic dye production. Renewability and eco-friendliness are the two major reasons that have led to the revival of these dyes and their gradual replacement with synthetic colorants.

*Colorimetric Measurement and Functional Analysis of Selective Natural Colorants… DOI: http://dx.doi.org/10.5772/intechopen.102473*
