Formulating a natural colorant containing wax for a one-step color-add application for fresh citrus

Authors: Bai, Jinhe; SUN, XIUXIU - University Of Florida; Baldwin, Elizabeth - Liz; HAGENMAIER, ROBERT - Former ARS Employee; RITENOUR, MARK - University Of Florida

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/24/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: In Florida, the early season fruits such as ‘Parson Brown’ and ‘Hamlin’ reach full maturity in terms of internal quality during early fall, but their peel are often still green due to the lack of cold nights needed to turn the fruit orange. The improvement of citrus peel color to better meet consumer expectations is important to the citrus industry. The current packinghouse practice is to first apply a dye, Citrus Red Number 2 (CR2), to improve the surface color and then to apply fruit wax to impart shine, retain moisture and slow fruit senescence. Citrus Red Number 2 used in the current practice has been listed by the European Union (EU) and the International Agency for Research on Cancer (IARC) as a group 2B carcinogen, which is why the citrus industry is looking for an alternative. In this research, a new method was developed to formulate natural colorant containing citrus waxes. Natural colorants, extracted from annatto seeds or red peppers, and carnauba wax (common wax used on citrus) were used as the major ingredients. The coatings were evaluated for shine and retention of moisture (properties of a wax), and as a surface color enhancer for citrus fruit (properties of a colorant). For wax function, the coatings were compared with carnauba wax alone (control) for reduction of water loss, maintenance of a proper internal modified atmosphere, reduction of respiration, and for imparting gloss to citrus fruit. For color enhancement, the effect of the coatings on masking the green/yellow colors and blemishes as well as imparting natural orange-like colors were determined. The stability of the coated fruit color was assessed under different temperature and light exposure conditions to simulate commercial storage and marketing. This research not only made use of alternative colorants from natural sources, but also made it possible to apply the colorant and wax in a one-step process, which protected the colorant from oxidation by combining the color in the wax.