**4.5. Intake**

In food chemistry, anthocyanins have been studied [68, 147, 148] in relation to changes and stability of colors in foods such as fruits during processing and storage and also for their use as natural colorants. Indeed, many types of anthocyanin food colorants have been developed and are now available to customize the appearance of foods. In horticulture, color conversion of flower pigments has become possible by new findings of anthocyanin research. Creation of flowers in new colors enriches our life; for example, the creation of blue roses [109] is a noteworthy achievement. Genetic engineering is the key technology for converting flower color and it became possible after the discovery of genes involved in anthocyanin biosynthesis and

**Figure 5.** Schematic of the general flavonoid biosynthetic pathway relevant to flower color (ANS: anthocyanidin synthase; CHI: chalcone isomerase; CHS: chalcone synthase; DFR: dihydroflavonol 4-reductase; F3H: flavonoid-3′ hydroxylase; F3´5H: flavonoid-3′5´hydroxylase FLS: flavonole synthase; 3GT: flavonoid 3-O-glucosyltransferase; MT:

elucidation of their expression mechanisms.

126 Phenolic Compounds - Natural Sources, Importance and Applications

Malonyl transferase) [146].

Anthocyanins are widely ingested by humans, mainly due to consumption [159] of red fruits (like berries and red grapes), vegetables such as red cabbage, red wines, cereals and purple corn. Accurate estimation of anthocyanin contents in foods and daily intake is critical in food science, nutrition and other related research fields. The type and concentration of anthocyanins differ widely among different fruits and vegetables. Intake levels of anthocyanins varies widely with region, season and among individuals with different social, cultural and educational backgrounds. High intake levels of anthocyanins can be achieved with the regular consumption of fruits (blueberries, blackberries, raspberries, strawberries, red grapes and saskatoon berries). Depending on nutritional habits, the daily intake has been estimated in the range [58] from several milligrams to hundreds of milligrams per person, while the consumption of other phytonutrients such as carotenoids, vitamin E and vitamin C are estimated at 5, 12 and 90 mg/day, respectively.

Regular consumers of red wine are likely to have [149] significantly higher intakes. A glass of red wine provides around 115 mg of polyphenols, contributing toward a total intake [58] of phenolic compounds of 1171 mg/person/day. In the United States, an average daily intake of anthocyanins has been estimated [119] at 215 mg during the summer and 180 mg during the winter. Wu et al. [160] estimated that the mean daily intake of anthocyanins is 12.5 mg/person in the United States; such a huge difference of the total anthocyanin daily intake estimation must result from different food intake data. The influence of methodological differences in the assessment, as well as nutritional, social and cultural differences of the investigated populations, may also explain the wide range of anthocyanin consumption estimated by different authors. Anthocyanin intake in the German young shows differences between girls and boys [161], decreasing from young childhood to adolescence.

Up to now, anthocyanins have not been detected in processed food such as canned food, bread, or cereals. Also, although prepared baby food containing blueberries, rich in anthocyanins, are expected to find these compounds, analyses have hardly detected them [162]. In young infants [163] the anthocyanidin intake was found to be zero.

Due to antioxidant and other potential beneficial properties, grapes, various berries, red cabbage and other anthocyanin-rich foods are becoming more popular. Berry extracts are also being commercialized as nutraceuticals and dietary supplements [164] to meet consumer demands.

Currently, there is no recommended intake level of anthocyanins for optimal health or to avoid adverse effects; however, future research and continued consumer interest will undoubtedly present opportunities for pursing dietary guidance recommendations.
