Polyphenols as Colorants

Abstract

Kalsec® Inc. 3713 West Main Street Kalamazoo, MI 49024, USA The market for natural colors for food applications is ever increasing. Consumers are Tel. 269-349-9711 seeking simpler and cleaner labels for their foods and are looking for alternatives to synthetic E-mail: dabasd@gmail.com ingredients. As a result, interest in natural products including natural colorants is obvious. This review explores the potential of polyphenols and polyphenol derived molecules as colorants. Special Edition 2 Polyphenols are classified into flavonoids or non-flavonoids and are known for their antioxidant Article Ref. #: 1000AFTNSOJSE2101 and biological activity. Anthocyanins are well known colored flavonoids but other polyphenols including many aurones and chalcones derivatives are also colored. Curcumin, demethoxyxur- Article History cumin, bisdemethoxycurcumin and cyclocurcumin are isolated from turmeric. Turmeric extract Received: January 25th, 2016 is used as a colorant in many food applications owing to its high heat stability. Anthraquinone Accepted: February 23rd, 2016 based pigments occur in nature, one of which is tetrahydroxylated anthraquinone – carminic Published: February 23rd, 2016 acid. Carminic acid and its lake are commonly used pigments and provide a red to pink hue depending on pH of a food or beverage. Usually colorless polyphenols can give rise to colored products by virtue of presence of enzymes or reaction with other substrates or both. Polyphenol Citation oxidase (PPO) plays an important role in these reactions. Typically polyphenol content is lower Dabas D. Polyphenols as colorants. after these reactions occur. Tea pigments are a good example where PPO oxidizes Epicatechin Adv Food Technol Nutr Sci Open J. 2016; SE(2): S1-S6. doi: 10.17140/ and epicatechin-3-O-gallate (EGCG) and other polyphenols. The reaction products being very AFTNSOJ-SE-2-101 unstable in nature interact chemically and generate pigments. During cocoa processing the nibs undergo fermentation, leading up to enzymatic reactions causing color development at the expense of polyphenols. Avocado seeds undergo similar reactions in presence of PPO and oxy- gen. Similarly in wine, new pigments called pyranoanthocyanins are generated from anthocya- nins. During juice extraction in apples, colored products are formed from colorless chalcones as a result of PPO activity. PPO products have been thought to be polymeric in nature but in the reviewed studies that is not the case. Among the polyphenols discussed in the study, aurones, chalcones and Hydroxy-anthraquinones (HAQs) have not been exploited to full potential. More research on optimizing isolation of pigments and using in food systems is needed. Regulatory hurdles will need to be cleared to enable their use in food applications.