Influence of Natural Pigments on Egg Quality and Yolk Colour Intensity - A Review

Abstract

Eggs are a great source of animal protein that are rich in fatty acids, selenium, B vitamins, provitamin A, amino acids, and folic acid. Egg quality and yolk colour are important attributes for consumers. They associate a higher intensity colour of yolk with a healthy egg which its rich in nutrients. Because hens are unable to synthesise pigments, they must come from feed mixtures. Furthermore, the synthetic colourants are added to laying hens diets to improve the yolk colour intensity. However, human health received more attention in the last time, so, the consumers are attracted by natural-coloured eggs. Carotenoids are the most numerous and widespread group of pigments in nature. They are a class of widely distributed pigments that include red, yellow, and orange colour. Numerous studies have examined the use of carotenoids, particularly yellow carotenoids, in animal feed, which aid to make egg yolks more orange in colour. They are found in different plants, microalgae, bacteria, fungi and have various biological functions, including increasing production, antioxidant, anti-inflammatory, antibacterial and immunomodulator role. For practical purposes, the cost of carotenoids from natural sources needs to be considered. The objective of this review was to summarise the recent findings in available literature data on the supplementation with natural pigments based on marigold and calendula flowers and paprika extracts for egg quality and yolk colour pigmentation which are preferred over pigments of synthesis, due to their costs and biodisponibility.

Keywords

• carotenoids
• laying hens
• marigold flowers
• paprika powder extract
• yolk colour