Anthocyanin Colorants from Fruits and Vegetables - ACS Symposium

Chapter 6

Anthocyanin Colorants from Fruits and Vegetables S. H a k e and J. Quinn

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GNT USA, Inc., 660 White Plains Road, Tarrytown, NY 10591

Understanding the relationship between the various internal and external factors that influence the color governance of new natural colors is important when choosing a color. This chapter will focus on the industries' criteria for natural colors and explain the driving factors influencing the demand for all natural ingredients, specifically focusing on natural red colors from fruits and vegetables. Two important external factors that influence the color governance are the regulatory or FDA policies and the demand from the customer or marketplace. In addition to research and development, an important internal factor is the relationship between nature, growers, and location.

© 2008 American Chemical Society

In Color Quality of Fresh and Processed Foods; Culver, C., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.

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Today's consumers are more educated than ever about food ingredients and additives. With obesity on the rise, especially in children, focus on portion size and nutritional value in food and beverages is getting a lot of attention from lawmakers in Washington. Retailers are also starting to educate their consumers. Stores such as Whole Foods and Trader Joe's have a strong consumer following because of their commitment to provide healthy, organic, and natural food products. For example, Whole Foods Market's internal quality standards team has developed a list of unacceptable food ingredients. Ingredients on this list include saccharin, FD&C artificial colors, bleached flour, monosodium glutamate, sulfites, and artificial flavors.(%) The retail products in these cases give the consumer the confidence that the products on the shelves will be nutritious and healthy. The demand for natural and organic ingredients has been on the rise over the last couple of years making the organic and natural products sector one of the fastest growing in the industry. In the past, the food and beverage industry has seen many trends including fat free, sugar free, soy, and low carb. More natural and healthy products are no longer a trend but rather a revolution to clean up existing products from artificial additives. New products are now being formulated with emphasis on all-natural ingredients. Consumers are also going through lifestyle changes to improve their eating habits. Food colors play an important role in formulating foods. Traditionally, mainstream products have been colored with artificial FD&C colors, however recently, the demand for an all-natural color has been on the rise. Color manufacturers and users now need to consider numerous factors. In this paper we will focus on red colors derived from fruits and vegetables. We will discuss the multiple steps that one should take into consideration. As shown in Figure 1, the foundation for developing a new color is Research & Development. There are also two outside factors that influence the Business Governance of new natural colors. The first factor is Regulatory / FDA and the second factor is the demand from the Customer / Marketplace. Additionally, there are some driving factors (People, Funding, Marketing) influencing the demand for all natural ingredients. One important factor is the influence that location and growers have on the naturally occurring red colors. While this factor will be discussed in more detail, this chapter will not discuss in depth the importance that Marketing and Funding play with Business Governance.

Research and Development Anthocyanin molecules are responsible for the natural red, blue, violet, and magenta colors found in various fruits, vegetables, and plants. The anthocyanin structure is a glycoside of flavylium or 2-phenylbenzopyrylium salts and are



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Figure 1. Business model for color governance. (See page 6 of color inserts.)

most commonly based on six anthocyanidins: pelargonidin, cyanidin, peonidin, delphinidin, petunidin, and malvidin0 The sugar molecule on this structure, may also be acylated with either a phenolic or aliphatic acid (2). There are currently over 275 identified anthocyanin structures which are closely related to nearly 5,000 flavonoid compounds (3). Figure 2 shows some common antho cyanin structures found in nature. Extraction of anthocyanins for colorants can be done naturally using just water and physical means. This can yield a highly concentrated product that can be used for coloring food substances around the world. When this method is utilized, other naturally occurring substances (vitamins, minerals, phytonutrients) in the fruit or vegetable are also retained. If the extraction process is carried out further by the use of solvents, a pure anthocyanin extract can be achieved. While a pure anthocyanin extract is highly concentrated, it is not currently permitted for use as a colorant in the United States. Anthocyanins act as pH indicators changing in both color shade and color intensity as the pH varies. At a pH of 1, anthocyanins will exhibit a very red color shade. As the pH increases up to 4.0, structural transformations will alter the color to a more red-blue hue. At a pH above 8.0, anthocyanins can shift to a blue, green, yellow, or colorless compound, with the most intensity seen at the lower pH values. While all anthocyanins exhibit a color shade shift with pH variation, the exact color hue will be dependent on the raw material source. With most food applications having a pH value between 3.0 - 5.0, fruit and vegetable juices for color can provide a wide range of natural red, pink and purple shades. Natural red colors from fruits and vegetables can be used in a variety of applications, including but not limited to, fruit preparations, beverages, dairy


72 (a)

OH

(b)

.OH HO

H

OH

OH

OH


JDH

HO-

OH

OH

Figure 2. Commonly found anthocyanin molecules, (a) Pelargonidin-3glycosid: main anthocyanin in strawberries, (b) Cyanidin: main anthocyanin in Roses, (c) Delphinidin: main anthocyanin in blue flowers

products, dry mixes, confections, vinegars, and frozen products. Because high concentrations can be achieved, when used as food colorant, they typically do not impart any flavor to the finished product. The stability of the natural colorant will depend on a variety of factors including the raw material source, processing parameters, pH of product, presence of sulfur dioxide, and available oxygen. While anthocyanin colorants are stable in most food applications, they can slowly oxidize over time or react with sulfur dioxide to form a colorless product. An experienced color supplier will be able to guide one in choosing the correct color source for ones application. Naturally occurring anthocyanin compounds can be found in numerous food products such as: red onion, strawberry, purple sweet potato, mango, cherry, plum, blueberry, red radish, tamarillo, and lychee (4). For commercial purposes the color yield, in combination with manufacturing procedures that are not too complex, time-consuming, or costly, must be examined. Traditionally grapes were used as a primary source for extracting anthocyanin based colors because of the wide availability (2), however, because this product is dependent on the wine industry, the price and quantity will vary seasonally. As a result, natural color companies have examined the use of other raw material sources. The most popular raw materials utilized today include elderberry, aronia, red cabbage, black carrot, and hibiscus. Photos of these raw materials can be seen on Plate 1.


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Regulatory/FDA Research shows us that anthocyanin molecules impart red, blue, violet, and magenta colors to food and beverage applications. Before these products can be manufactured commercially, it is important to understand the FDA regulation of colors. FDA does not recognize the term "natural color". Any ingredient used to impart color is considered an additive and must be labeled as a colorant. For example: if a cherry juice imparts a red color to a strawberry yogurt, the cherry juice is considered a color additive. The labeling of the cherry juice must be in compliance with 21 CFR 101.22 (k). Hence, anything that is used for the purpose of adding color to a food product becomes an additive and is therefore regulated as a color by the FDA. Under the color regulation there are certified colors and colors exempt from certification. Certified colors are FD&C colors such as FD&C Red# 40. Each batch of these colors must be certified by the FDA. Colors exempt from certification are not required to have every batch certified by the FDA, however, good-manufacturing practices apply. FDA legal classification for colors derived from fruits and vegetables with a history of edible use is as follows: Color Exempt from Certification: Fruit Juice color 21 CFR 73.259 and Vegetable juice color 21 CFR 73.260. The color regulations mentioned above were amended by GNT in 1994 to include the use of dry materials. Previous to this amendment, the regulations allowed for the fruit or vegetable juice color to be prepared by expressing the juice, using water only (no solvents) from mature varieties of fresh, edible fruits or vegetables only. The juice can only be extracted from the portion of the fruit or vegetable that is typically consumed. With the new amendement, color manufacturers now have the option of using dried fruits and vegetables, with the help of water, to make fruit and vegetable juice colors under 21CFR 73.259 and 21 CFR 73.260. Unlike other areas of federal regulation, the statutory provisions with respect to colors contain no clear mechanisms or avenues for the FDA to pursue a "flexible" approach to the regulation of colors. The current color regulations do not allow for selective extraction of anthocyanins and therefore only fruits and vegetables with a history of edible use would be permitted. This now eliminates anthocyanin sources from plants such as roses. Since selective extraction is not permitted, one can focus on extracting color from the whole fruit and vegetable. When doing this, it is important to have a good understanding of other naturally occurring substances (in addition to anthocyanins) found in fruits and vegetables that will have influence on color hue and stability. Before we focus on the growing challenges of fruits and vegetables, one needs to understand the Customers and Marketplace.


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Customers/Marketplace The food and beverage industry uses color to increase shelf life and to improve the appearance of products. The color appearance of a product catches the consumer's eye and can help move a product off the shelf more quickly. In the past, natural colors were used only in speciality foods aimed at a niche market but because of consumer awareness and increasing health concerns, natural colors are now widely used in mainstream products developed for a wider range of the population. Because today's natural colors from fruits and vegetables can be found in mainstream products, the color industry must be able to produce supply in large volumes. Customers not only demand consistency in color strength and color hue, but also quality of the product. Since nature does not ensure a consistent supply, it is important to work with a supplier that has the capabilities of growing a product in multiple regions and understands how to hedge against these inconsistencies. The marketplace for mainstream products also looks for price stability. A natural color being used in a common food item must provide the price stability that the manufacturer provides to the end consumer. Since color is added to increase the shelf life of a product, stability of the natural color in the end product is essential. The stability of each fruit and vegetable color depends on the way the anthocyanin interacts with other ingredients. An example of this is products containing high doses of vitamin C (greater than 60mg per 8oz serving) could have a negative effect on the stability of the anthocyanin. Stability also depends on a variety of factors such as the raw material source. Various anthocyanin structures found in fruits and vegetables have a different stability in different applications. For optimum stability the right combination of fruits and vegetables should be used and an experienced color supplier can ensure that you are using the correct combination.

Nature/Growers/ Location Through research and development it is shown that various anthocyanins found in fruits and vegetables offer different stability, color shades, and color hues to food and beverages. Because FDA regulation only permits the use of fruits and vegetables with a history of edible use, we can say that the key in delivering consistent, price stable natural colors lies in the raw material source. Under the current regulation, a fruit or vegetable juice color can be concentrated approximately 20 to 30 times. It should be noted that a common mainstream product could require one million pounds of concentrated product. For example, if a company launches a new product with red grape juice color, 20



75 to 30 million pounds of grapes would be needed. This would have a significant effect not only on the supply and demand on grapes, but also on the price stability. To increase the supply of grapes to meet this demand would take five to seven years. A more efficient way to supply natural colors to mainstream products is to grow fruits and vegetables where the supply can easily be increased from one year to another. Additionally, a serious supplier of natural color from fruits and vegetables has to have the capability of growing the product in multiple regions. Since anthocyanin molecules are responsible for the natural red colors found in various fruits and vegetables, the relative anthocyanin content of these red fruits and vegetables has a significant effect on price. Our research found that the anthocyanin content in different fruits fluctuates depending on variety, location, and harvest time. In Figure 3, we measured the anthocyanin content in seven different fruits (5). We found the highest percentage of anthocyanins were in Elderberry. This percentage was then used as a benchmark. It was also seen that while elderberries have the highest percentage of anthocyanins, they also have the highest level of fluctuation. The relative anthocyanin content was also high in chokeberries and black currants.

Figure 3. Relative anthocyanin content in various fruits and vegetables.

In Figure 4 we examined the effect of harvesting date on anthocyanin content in different varieties of red fruits (5). While some varieties showed small fluctuations, others showed a fluctuation of over 30% indicating that understanding the variety, location, and harvest time is all essential to producing a high quality natural color.



Figure 4. Influence of harvesting date on relative anthocyanin content in different varieties of anthocyanin containing fruits and vegetables.

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Having control over the harvesting of fruits and vegetables can also play an important role in price stability. Typically, a fruit or vegetable bought in a grocery store has 30 to 40 % less anthocyanins than one that is grown commercially for the purpose of color. This is mainly due to the fact that fruits found in most stores are picked before they are ripe. Since nature varies but the food and beverage industry wants a natural color that is consistent from year to year, natural color manufacturers must take the inconsistency from nature and standardize the end product. This is where Art meets Science. While the color variation between crops and growing seasons is unpredictable, it can be monitored. Cultivation conditions from soil, weather, and harvesting time, can all influence the color outcome as shown with the various shades of red in Figure 5 (5).

Figure 5. Affect of cultivation conditions, processing conditions, and variety on the color shade and color hue. (See page 6 of color inserts.)



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Plate 1. Fruits and vegetables commonly used for the production of natural food colors, (a) Red Cabbage, (b) Black Carrot, (c) Elderberry, and (d) Hibiscus (See page 7 of color inserts.)



Figure 6. Converting nature's color variation into a standardized natural colorant. (See page 7 of color inserts.)


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81 Art is taking all these variables and mixing them into one standardized color as shown in Figure 6 (5). Making a standardized color from the various starting materials involves influencing the color by optimizing processing conditions. It is a color manufacturer's responsibility to convert the variation into a standardized color that can be used by the food industry.


Conclusion With good Color Product Governance one can achieve a consistent, price stable, natural color from fruits and vegetables. Natural red colors can be found in many mainstream food and beverage applications throughout the United States. As the demand for natural ingredients increases, so will the demand for these natural colors. As homework, the natural color industry must now look into developing a supply of natural blue and green colorants which are currently not available.

References 1. 2. 3. 4.

5.

Whole Foods Market Home Page. http:www.wholefoodsmarket.com (accessed Mar 13, 2007) Henry, B.S. Natural Food Colors in Natural Food Colorants; Hendry, G. A. F., Houghton, J. D., Eds; Chapman & Hall: New York, 1996; pp 40-79. Francis, F.J. Food Colorings in Colour in Food; MacDougall, D. B., Ed.; Woodhead Publishing Ltd.: Cambridge, UK, 2002; pp 297-331. Jackman, R.L.; Smith, J. L. 1996. Anthocyanins and Betalins In Natural Food Colorants; Hendry, G. A. F, Houghton, J. D., Eds.; Chapman & Hall: New York; pp 244-310. Stich, E. 2004. Unpublished. GNT Europa. Kackertstrasse 22, Aachen, Germany.


Anthocyanin Colorants from Fruits and Vegetables - ACS Symposium

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