Bioavailability of Carotenoids Incorporated Into Processed Foods: Bread and Mayonnaise

Carotenoids are a diverse group of natural-occurring fat-soluble pigments. Whilst over 600 different types have been characterised around 20 have been found in human tissue in the postprandial state, however, over 90% of these absorbed carotenoids are made up of 6 specific types (alpha-Carotene, beta-carotene, Lycopene, Lutein, Zeaxanthin and Cryptoxanthin)

There is good evidence to suggest that carotenoids play a notable role in human health both through their pro-vitamin activity and as biological antioxidants. Carotenoids are believed to be responsible for the beneficial effects of fruits and vegetables in preventing human chronic diseases such as cancer and cardiovascular disease. Increasing fruit and vegetables intakes in individuals can sometimes be difficult and unsustainable, therefore, increasing bioavailability may be an effective alternative approach to maximise health outcomes.

A notable number of vegetables are rich sources of carotenoids, however, the amounts available to the human body for metabolism are often small due to poor bioavailability. For instance, studies have shown that bioavailability of carotenoids from carrots and tomatoes can be as low as 1-3%. The bioavailability of carotenoids has been shown to depend on factors such as their source, degree of cooking, processing, mechanical breakdown, presence of fat and interactions between carotenoids. Whilst the presence of fat significantly increases carotenoid absorption, the oil type, quantity and form it is in all affect bioavailability.

Recent work suggests that carotenoid bioavailability improves when fat is present in the form of mayonnaise rather than as plain oil. This may be due to the emulsion properties of mayonnaise which allows better solubilisation of amphiphilic compounds such as carotenoids. Mayonnaise has also been shown to be more miscible in gastric juices (compared to plain oil) and this too may be contributing to the greater absorption of carotenoids.

The present study builds upon this previous work and studies carotenoid bioavailability in processed food systems. Using a bread-mayonnaise meal the study compares carotenoid bioavailability when it is incorporated either into the bread or the mayonnaise. Furthermore, the study investigates the impact of mayonnaise on the bioavailability of carotenoids incorporated into a processed food (bread). The study will focus on the bioavailability of three principle carotenoids found in foods, alpha-carotene, beta-carotene and lycopene. Carrot and tomato are used as the sources of carotenoids.