Zeaxanthin-Biofortified Popcorn for Eye Health ^†

Abstract

Zeaxanthin is one of only two dietary carotenoids accumulated in the human macula. A key role of zeaxanthin is to protect the eyes’ photoreceptors from damage induced by blue light. Photoreceptor damage can lead to macular degeneration, which is the leading cause of blindness in Australia. Unfortunately, zeaxanthin is fairly rare in our diet. Popcorn (Zea mays var. everta) is a good dietary source of zeaxanthin, but the creation of zeaxanthin-biofortified popcorn potentially allows less popcorn to be consumed for an increased dietary dose of zeaxanthin. As zeaxanthin is an orange pigment, breeding for zeaxanthin gives popped kernels a naturally buttery colour, unlike standard popcorn, which is virtually white. The creation of naturally buttery-coloured popcorn potentially negates the practise of adding artificial butter-colourants, while also providing an excellent source of dietary zeaxanthin. The action of popping involves a combination of high-temperature and high-pressure, sufficient enough for starch to liquefy, and for the tiny beads of moisture within starch bodies to reach an extremely high pressure. Eventually, the kernel pericarp can no longer withstand this pressure, and an explosion occurs, resulting in butterfly-shaped popcorn. These extreme conditions, however, lead to an approximate 50% decline in zeaxanthin concentration following popping, and a gradual further 25% reduction over the next 24 h. Consequently, in order to optimise zeaxanthin intake, popcorn should be eaten as soon as possible after popping. Zeaxanthin-biofortified popcorn provides an additional dietary source of zeaxanthin, potentially reaching a sector of the community more prone to low zeaxanthin intake.