The nutritional enhancement of plant foods 201 GGPP Phytoene synthase Phytoene Phytoene desaturase Lycopeneβ- cyclase (Icy) tend β-ca Fig 8. 2 The carotenoid biosynthetic pathway(simplified) of an endosperm-specific promoter. The choice of promoter will very much affed the timing and tissue-specific expression of a gene Surprisingly, seeds that expressed psy and crt did not accumulate lycopene Instead they contained B-carotene and other xanthophylls. Thus it would seem that the enzymes required to make these metabolites are either normally expressed in rice endosperm or are induced if lycopene is formed. The maximum level of carotenoids in the endosperm of plants that were heterozygous for the transgenes was 1.6mgkg" which is likely to help to meet the nutritional needs of people consuming rice as a staple. Interestingly, good progress is being made in adding a gene coding for ferritin-the iron storage protein found in mammals nd plants-to rice. It is likely that this would, in addition, help improve the iron deficiency also seen in these communities if it is shown to be bioavailable The controversy over the use of advanced technologies for producing sus- tainable food in the developing world has been addressed by the developers of modified rice. They have in effect waived all intellectual property rights for exploitation of the technologies in the developing world and are actively involved in assisting the International Rice Research Institute to breed stable and agro- nomically successful lines for use in vitamin A-deficient areas. 8.5 Relationship of structure to nutritional quality cavalla The overall content of a given nutrient in a food is not always a useful indicator of its nutritional value because not all of the nutrient present is absorbed. Nutri- tionists must concern themselves with understanding the proportion of an avail-of an endosperm-specific promoter. The choice of promoter will very much affect the timing and tissue-specific expression of a gene. Surprisingly, seeds that expressed psy and crt did not accumulate lycopene. Instead they contained b-carotene and other xanthophylls. Thus it would seem that the enzymes required to make these metabolites are either normally expressed in rice endosperm or are induced if lycopene is formed. The maximum level of carotenoids in the endosperm of plants that were heterozygous for the transgenes was 1.6 mg kg-1 which is likely to help to meet the nutritional needs of people consuming rice as a staple. Interestingly, good progress is being made in adding a gene coding for ferritin – the iron storage protein found in mammals and plants – to rice.20 It is likely that this would, in addition, help improve the iron deficiency also seen in these communities if it is shown to be bioavailable. The controversy over the use of advanced technologies for producing sus￾tainable food in the developing world has been addressed by the developers of modified rice. They have in effect waived all intellectual property rights for exploitation of the technologies in the developing world and are actively involved in assisting the International Rice Research Institute to breed stable and agro￾nomically successful lines for use in vitamin A-deficient areas. 8.5 Relationship of structure to nutritional quality (bioavailability) The overall content of a given nutrient in a food is not always a useful indicator of its nutritional value because not all of the nutrient present is absorbed. Nutri￾tionists must concern themselves with understanding the proportion of an avail￾The nutritional enhancement of plant foods 201 Fig. 8.2 The carotenoid biosynthetic pathway (simplified)