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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Citrus and Other Subtropical Products Research » Research » Publications at this Location » Publication #319788

Research Project: Quality, Shelf-life and Health Benefits for Fresh, Fresh-cut and Processed Products for Citrus and Other Tropical/Subtropical-grown Fruits and Vegetables

Location: Citrus and Other Subtropical Products Research

Title: Evaluation of natural colorants and their application on citrus fruit

item Bai, Jinhe
item SUN, XIUXIU - University Of Florida
item RITENOUR, MARK - University Of Florida
item Plotto, Anne
item Baldwin, Elizabeth - Liz

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/17/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Warm temperatures can often result in poor peel color of some citrus varieties, especially early in the harvest season. Under these conditions, Florida oranges, temples, tangelos, and K-Early citrus fruit are allowed to be treated with Citrus Red No.2 (CR2) to help produce a more acceptable peel color. Unfortunately, CR2, the commercial colorant used in Florida, has been listed as a group 2B carcinogen by the European Union (EU) and the International Agency for Research on Cancer (IARC). Although not likely dangerous at levels used on citrus, and on a part of the fruit that is not ingested, there is a negative health perception, and thus, a need for natural or food grade alternative colorants to replace CR2 for use on citrus. The current research demonstrated that three out of five oil-soluble natural red/orange colorants resulted in peel colors somewhat similar to the industry standard CR2. These three (annatto extract, paprika extract and paprika oleoresin) were selected for further in vivo studies. The stability of the natural colorants along with CR2 was evaluated by applying them on test papers and then on fresh ‘Hamlin’ oranges. All natural colorants were found to be easily oxidized and faded when applied on test papers. However, coating the colored surfaces with carnauba wax apparently inhibited oxidation and the subsequent discoloration of the surface. When applying the natural colorants to ‘Hamlin’ oranges before waxing, the treatments retained the improved color after storage in the dark at 5 °C, simulating cold storage. However, only annatto extract maintained a stable color when subsequently stored in a simulated market condition, at 23 °C exposed to 300 Lux of standard fluorescent white light.