The evaluation of the bioaccessibility of almond nutrients is incomplete. However, it may have implications for the prevention and management of obesity and cardiovascular disease. This study quantified the release of lipid, protein, and vitamin E from almonds during digestion and determined the role played by cell walls in the bioaccessibility of intracellular nutrients. Natural almonds (NA), blanched almonds (BA), finely ground almonds (FG), and defatted finely ground almonds (DG) were digested in vitro under simulated gastric and gastric followed by duodenal conditions. FG were the most digestible with 39, 45, and 44% of lipid, vitamin E, and protein released after duodenal digestion, respectively. Consistent with longer residence time in the gut, preliminary in vivo studies showed higher percentages of nutrient release, and microscopic examination of digested almond tissue demonstrated cell wall swelling. Bioaccessibility is improved by increased residence time in the gut and is regulated by almond cell walls.

Carotenoids form one of the most important classes of plant pigments and play a crucial role in defining the quality parameters of fruit and vegetables. Their role in the plant is to act as accessory pigments for light harvesting and in the prevention of photo‐oxidative damage, as well as acting as attractants for pollinators. Their function as antioxidants in the plant shows interesting parallels with their potential role as antioxidants in foods and humans. Carotenoids are products of the isoprenoid biosynthetic pathway. The enzymes leading to carotenoid biosynthesis have all been characterised, and more recently the genes encoding these enzymes have been cloned from bacteria, fungi and plants. New information on enzyme activities and the factors leading to the regulation of the pathway is reviewed. Vitamin A deficiency is a widespread problem in the developing world, causing blindness, particularly in the young. This has driven research into finding ways of introducing provitamin A carotenoids into staple crops, and this has recently been achieved in rice and canola through genetic manipulation. The fact that carotenoids show protective activity in vitro and in vivo against a variety of degenerative disease end points has also give impetus to studying whether increasing intakes of the commonly consumed carotenoids would have public health benefits in the developed world. Human intervention studies have been undertaken using supplements of β‐carotene rather than utilising foods with enhanced carotenoid levels, but no potential benefit has been shown. Indeed, there is evidence of an increased health risk from the consumption of β‐carotene supplements. These observations suggest that the threshold between the beneficial and adverse effects of some carotenoids is low and provides a strong stimulus to further understanding the functional effects of specific carotenoids. Specific needs for future research are identified in the review. © 2000 Society of Chemical Industry