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Lycopene is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables, such as red carrots, watermelons, gac melons, and papayas, but it is not present in strawberries or cherries. Although lycopene is chemically a carotene, it has no vitamin A activity. Foods that are not red may also contain lycopene, such as asparagus and parsley.
Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids. Vitamin A has multiple functions: it is important for growth and development, for the maintenance of the immune system, and for good vision. Vitamin A is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light and color vision. Vitamin A also functions in a very different role as retinoic acid, which is an important hormone-like growth factor for epithelial and other cells. Yet the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal.
Golden rice is a variety of rice produced through genetic engineering to biosynthesize beta-carotene, a precursor of vitamin A, in the edible parts of rice. It is intended to produce a fortified food to be grown and consumed in areas with a shortage of dietary vitamin A, a deficiency which each year is estimated to kill 670,000 children under the age of 5 and cause an additional 500,000 cases of irreversible childhood blindness. Rice is a staple food crop for over half of the world's population, making up 30–72% of the energy intake for people in Asian countries, making it an excellent crop for targeting vitamin deficiencies.
Carotenoids, also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria and fungi. Carotenoids give the characteristic color to pumpkins, carrots, corn, tomatoes, canaries, flamingos, and daffodils. Carotenoids can be produced from fats and other basic organic metabolic building blocks by all these organisms. The only animals known to produce carotenoids are aphids and spider mites, which acquired the ability and genes from fungi, and it is produced by endosymbiotic bacteria in whiteflies. Carotenoids from the diet are stored in the fatty tissues of animals, and exclusively carnivorous animals obtain the compounds from animal fat. In the human diet, absorption of carotenoids is improved when consumed with fat in a meal. Cooking carotenoid-containing vegetables in oil increases carotenoid bioavailability.
Chromoplasts are plastids, heterogeneous organelles responsible for pigment synthesis and storage in specific photosynthetic eukaryotes. It is thought that like all other plastids including chloroplasts and leucoplasts they are descended from symbiotic prokaryotes.
β-Carotene is an organic, strongly colored red-orange pigment abundant in plants and fruits. It is a member of the carotenes, which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons. Among the carotenes, β-carotene is distinguished by having beta-rings at both ends of the molecule. β-Carotene is biosynthesized from geranylgeranyl pyrophosphate.
Ingo Potrykus is Professor Emeritus of Plant Sciences at the Institute of Plant Sciences of the Swiss Federal Institute of Technology (ETH), Zurich from which he retired in 1999. His research group applied gene technology to contribute to food security in developing countries. Together with Peter Beyer, he is one of the co-inventors of golden rice. In 2014 he was chairman of the Golden Rice Humanitarian Board.
γ-Carotene is a carotenoid, and is a biosynthetic intermediate for cyclized carotenoid synthesis in plants. It is formed from cyclization of lycopene by lycopene cyclase epsilon. Along with several other carotenoids, γ-Carotene is a vitamer of vitamin A in herbivores and omnivores. Carotenoids with a cyclized, beta-ionone ring can be converted to vitamin A, also known as retinol, by the enzyme Beta-carotene 15,15'-dioxygenase; however, the bioconversion of gamma-carotene to retinol has not been well-characterized.
Cryptoxanthin is a natural carotenoid pigment. It has been isolated from a variety of sources including the petals and flowers of plants in the genus Physalis, orange rind, papaya, egg yolk, butter, apples, and bovine blood serum.
Blakeslea trispora is a mould and member of the division Zygomycota. This species has been well studied for its ability to produce carotenoids, particularly, β-carotene and lycopene. β-carotene is a vitamin A precursor and both of β-carotene and lycopene play a significant role in the inhibition of oxidative stress. Blakeslea trispora is commonly isolated from soil samples throughout the Southern United States and Southern Asia. B. trispora is a pathogen of tropical plants. In vivo pathogenicity testing using animal models suggests this fungus is not a cause of animal or human disease.
Damascenones are a series of closely related chemical compounds that are components of a variety of essential oils. The damascenones belong to a family of chemicals known as rose ketones, which also includes damascones and ionones. beta-Damascenone is a major contributor to the aroma of roses, despite its very low concentration, and is an important fragrance chemical used in perfumery.
Phytoene synthase is a transferase enzyme involved in the biosynthesis of carotenoids. It catalyzes the conversion of geranylgeranyl pyrophosphate to phytoene. This enzyme catalyses the following chemical reaction
Genetically modified rice are rice strains that have been genetically modified. Rice plants have been modified to increase micronutrients such as vitamin A, accelerate photosynthesis, tolerate herbicides, resist pests, increase grain size, generate nutrients, flavours or produce human proteins.
Peter Beyer is a German Professor for Cell Biology at the Faculty of Biology of the University of Freiburg. He is known as co-inventor of Golden Rice, together with Ingo Potrykus from the ETH Zurich.
A genetically modified tomato, or transgenic tomato, is a tomato that has had its genes modified, using genetic engineering. The first trial genetically modified food was a tomato engineered to have a longer shelf life, but never made it to market. Currently there are no genetically modified tomatoes available commercially, but scientists are developing tomatoes with new traits like increased resistance to pests or environmental stresses. Other projects aim to enrich tomatoes with substances that may offer health benefits or be more nutritious. As well as aiming to produce novel crops, scientists produce genetically modified tomatoes to understand the function of genes naturally present in tomatoes.
Yellow cassava is a new, yellow-fleshed breed of one of the most popular root crops in the tropics. Regular cassava is a staple crop in tropical countries which 300 million people rely upon for at least 10% of their daily caloric intake, in 15 African countries “In the Democratic Republic of the Congo, cassava is estimated to provide more than 1000 kcal/day to over 40 million people”. Three yellow root cassava varieties, UMUCASS 36, UMUCASS 37, and UMUCASS 38, are being grown in Nigeria for their high concentrations of β-carotene. β-carotene is a precursor to Vitamin A. Vitamin A deficiency is a major issue, especially in Africa. Nigeria in particular sees a prevalence of Vitamin A deficiency in nearly one third of children under five years old. Since cassava is a major food staple, yellow cassava shows great potential to alleviate Vitamin A deficiency in Africa.
15-cis-phytoene desaturases, are enzymes involved in the carotenoid biosynthesis in plants and cyanobacteria. Phytoene desaturases are membrane-bound enzymes localized in plastids and introduce two double bonds into their colorless substrate phytoene by dehydrogenation and isomerize two additional double bonds. This reaction starts a biochemical pathway involving three further enzymes called the poly-cis pathway and leads to the red colored lycopene. The homologous phytoene desaturase found in bacteria and fungi (CrtI) converts phytoene directly to lycopene by an all-trans pathway.
Phytoene desaturase (lycopene-forming) are enzymes found in archaea, bacteria and fungi that are involved in carotenoid biosynthesis. They catalyze the conversion of colorless 15-cis-phytoene into a bright red lycopene in a biochemical pathway called the poly-trans pathway. The same process in plants and cyanobacteria utilizes four separate enzymes in a poly-cis pathway.
Prolycopene isomerase is an enzyme with systematic name 7,9,7',9'-tetracis-lycopene cis-trans-isomerase. This enzyme catalyses the following chemical reaction
Paprika is a ground spice made from dried red fruits of the larger and sweeter varieties of the plant Capsicum annuum, called bell pepper or sweet pepper. The most common variety used for making paprika is tomato pepper, sometimes with the addition of more pungent varieties, called chili peppers, and cayenne pepper. In many languages, but not English, the word paprika also refers to the plant and the fruit from which the spice is made.
References
- ↑ Romer, S.; Fraser, P.D.; Kiano, J.W.; Shipton, C.A.; Misawa, N; Schuch, W.; Bramley, P.M. (2000). "Elevation of provitamin A content of transgenic tomato plants". Nature Biotechnology. 18 (6): 666–669. doi:10.1038/76523. PMID 10835607.
- ↑ "The Science of Golden Rice" . Retrieved 14 November 2015.