Potatoes impact

In a very recent study in potatoes, inhibition of LCYE accumulation was accomplished by an antisense LcyE driven by the patatin promoter and allowed rechanneling of lycopene toward the P-carotene branch of the pathway to produce up to 14-fold increased levels of P-carotene as well as up to 2.5-fold increased total carotenoids. RNAi and TILLING for manipulation of carotenogenesis have yet to be reported, but these new techniques for suppression of function and generation and selection of allelic diversity are likely to impact future research and production of varieties with enhanced pigment accumulation. 

Bell, H. A., Down, R.E., Fitches, E.C., Edwards, J.P. and Gatehouse, A.M.R. (2003). Impact of genetically modified potato expressing plant derived insect resistance genes on the predatory bug, Podisus maculiventris (Heteroptera Pentatomidae). Biocontrol Science and Technology 13 729-741. 

The development of a by-production system could further minimize the cost of such plant-derived products. For example, potatoes are the raw material for the production of technical grade starch. During this process, soluble proteins are separated by heat treatment and sold as animal fodder. Recombinant proteins could be produced in transgenic potato tubers as a by-product of starch extraction, and this would be useful for proteins produced in large amounts with a low commercial impact, like structural fiber proteins. 

In practice this means that BHT can be present at up to 100 mg/kg in the fat fraction of manufactured foods such as baked goods and fried foodstuffs such as potato crisps or fried chicken. Although higher levels are permitted in chewing gum and dietary supplements, these might be expected to have a lesser impact on intakes because of the relatively small amounts of such foods consumed. 

Researchers are working to produce recombinant proteins from viruses in plants so that the leaves, fruit, or root (such as potatoes) would be edible forms of vaccine. A vaccine that is eaten may be more appealing and suitable than injections, particularly in poor parts of world with limited access to skilled health-care professionals. But there are barriers to the development of plant vaccines. First, there are technical issues. For example, would conditions within the stomach allow the immune system to respond to the protein to provide protection Additionally, some people are concerned about the environmental and health risks of growing vaccine-producing plants in fields. Could the food be safely processed and shipped While the development of plant-based vaccines has been a research success since first reported in 1992, it remains uncertain whether this form of biotechnology will eventually have a major impact on public health. 

The phenotype of a potato plant is very plastic (environmentally variable) with regard to many traits of interest for potato breeders. The effect of production environment on traits such as yield, tuber number, tuber size, specific gravity, and processing quality presents a challenge that is difficult to overcome. It requires the testing of clones in multiple years and locations. For example, quantitative trait loci have been detected for tuber starch content, but few were stable across environments (Schafer-Pregl et al., 1998). Similarly, environment has a laige impact on... 

Friedman, M., McDonald, G. (1999a). Postharvest changes in glycoalkaloid content of potatoes. In L. Jackson, M. Knize (Eds.). Impact of Food Processing on Food Safety, Vol. 459 (pp. 121-143). Plenum Press, New York. 

Shomer, L, Rao, M. A., Bourne, M. C., Levy, D. (1993). Impact of temperature and cellulose treatments on rheological behaviour of potato-tuber cell-suspensions. J. Sci. FoodAgric., 63, 245-325. 

Urrutia-Benet, G., Balogh, T., Schneider, J., Knorr, D. (2007). Metastable phases during high-pressure-low-temperature processing of potatoes and their impact on quality-related parameters. J. Food Eng., 78,375-389. 

Nutritional Value of Potatoes Digestibility, Glycemic Index, and Glycemic Impact... 

In this chapter we review the relationship between potato consumption and blood glucose responses, and explore causes and variations in the glycemic impact of potatoes, and the opportunities that they provide for the potato industry. 

Relevance to potatoes Gl gives an inflated idea of the glycemic impact of entire potatoes (Table 13.2) because it refers to the available carbohydrate alone, yet potatoes contain only about 20% available carbohydrate. Because it is an index, Gl does not directly indicate how glycemic impact is affected by the quantity of food consumed, unlike RGI. 

Relevance to potatoes Unlike Gl, RGI refers to the relative glycemic effect of the entire food, and depends on food quantity consumed (Table 13.2), so it allows a direct comparison ofthe relative glycemic impact of any amount of potato, such as a serving or lOOg, with a serving or any other amount of another food (Table 13.2). For potato RGI is much lower than Gl because fresh potatoes contain only about 20% available carbohydrate. 

Definition A single unit of RGI. One GGE unit is equivalent in glycemic effect to one gram of glucose. For example, one microwaved potato (Table 13.2) with a relative glycemic impact (RGI) of 15 GGE would... 

Relevance to potatoes Because it has weight units GGE can be used as if it were a food component, but representing glycemic impact. It allows the relative effect of a food to be shown concurrently with nutrient values for the food in food composition tables (e.g. Table 13.2), so has been termed a Virtual Food Component (Monro, 2004). 

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