Bioaccessibility of phytoene and phytofluene is superior to other carotenoids from selected fruit and vegetable juices

Highlights

• Carotenoid bioaccessibility (BA) was assessed in 4 vegetable and fruit juices.

• The BA of the major dietary carotenoids and that of phytoene/phytofluene was compared.

• Phytoene had the highest BA, followed by phytofluene in almost all juices.

• The markedly different shape of phytoene/phytofluene could explain their high BA.

• The BA of phytoene varied between 32 and 97%, that of phytofluene between 27 and 94%.

Abstract

Phytoene and phytofluene are major abundant dietary carotenoids largely ignored in the context of agro-food and health. The bioaccessibility of phytoene and phytofluene in tomato, carrot, blood orange (sanguinello cultivar), and apricot juices was analysed following simulated gastro-intestinal digestion with coffee cream as a lipid source, and compared with that of other main carotenoids from these matrices. The bioaccessibility of phytoene and phytofluene, and also total carotenoid bioaccessibility, followed the order: sanguinello > apricot > tomato > carrot. Phytoene was consistently the carotenoid with the highest bioaccessibility, up to 97%, generally followed by phytofluene. The higher bioaccessibility of these carotenoids could mainly be due to their marked difference in chemical structure and matrix distribution. For most juices, cis-isomers presented a higher bioaccessibility than their all-trans counterparts (P < 0.05). The dietary source that provided highest amounts of potentially absorbable phytoene/phytofluene was by far tomato juice (5 mg/250 mL juice).

Introduction

Many studies suggest that a diet rich in fruits and vegetables can decrease the risk of developing certain chronic diseases (World Cancer Research Fund & American Institute for Cancer, 2007). A convenient and efficient way to include fruits and vegetables in our daily diet is via juices. Juices are a rich source of nutritionally important compounds such as vitamins and minerals. Many juices are also a good source of carotenoids. Within the carotenoid family, there are compounds that have been largely ignored in the context of agro-food and health such as phytoene (PT) and phytofluene (PTF). Although the beneficial effect of these carotenoids on human health is still disputed, several reports have raised questions about their influence on human health (Kaulmann and Bohn, 2014, Meléndez-Martínez et al., 2015, Nishino et al., 2002). However, these colourless carotenoids are present in a wide variety of fruits and vegetables. According to one study, the daily per capita intake of phytoene and phytofluene combined has been estimated to represent 16% of the total dietary intake of carotenoids (Biehler et al., 2012). Interestingly, in the same study, the intake of phytoene (2.0 mg) appeared to be superior to that of carotenoids such as lycopene or lutein (1.8 and 1.5 mg, respectively). As the intake in the studied country (Luxembourg) is expected to be similar to that of other European countries, the results emphasize the importance of these carotenoids regarding carotenoid dietary intake in Europe. However, in order to estimate possible health benefits of these carotenoids, it is not only necessary to know their dietary intake, but also which fraction of this is truly available to the human body for supporting physiological functions i.e. their bioavailability.

Taking into account that carotenoids are lipophilic, they must be released from the food matrix and emulsified into lipid droplets and then incorporated into mixed micelles prior to their uptake and absorption. These are considered key steps regarding the bioavailability of carotenoids and some of the factors that govern these steps can be evaluated in part by in vitro models (Alminger et al., 2014, Biehler and Bohn, 2010). Despite that these models are often static and do not account for host factors influencing carotenoid bioavailability such as transporters (Bohn et al., 2017), in vitro studies can be very useful to study the impact of the food matrix on carotenoid release and potential availability during the digestion process. These methods are cheaper, less time-consuming, simpler and more reproducible than in vivo models, due to controlled conditions, and elimination of inter-individual differences (e.g. genetic differences (Biehler & Bohn, 2010)), and are thus proposed for hypothesis building prior to confirmation by human studies.

The objective of the present work was to compare the bioaccessibility of phytoene and phytofluene with that of other major dietary carotenoids in fruit and vegetable juices with different carotenoid patterns, in order to assess the importance of phytoene/phytofluene regarding their contribution to total carotenoid intake and availability, as very little information on this topic is available. The effect of the cis-trans configuration of the carotenoids on their bioaccessibility was also evaluated. This study provides information on the concentration of the colourless carotenoids and their bioaccessible fraction from several fruit and vegetable juices, and contributes to the understanding of factors that can modulate the bioaccessibility of lipophilic secondary plant constituents.