Potato tubers used for the manufacture of potato chips and fries need to meet stringent quality control guidelines. One of the most important of these is a requirement that fried products are uniformly light colored after cooking.
Storing potatoes at low temperatures results in an accumulation of the sugars glucose and fructose. These undergo chemical reactions during cooking that give rise to dark-colored, bitter-tasting chips and fries that may have unacceptable amounts of acrylamide. Acrylamide is a compound found in carbohydrate-rich cooked at high temperatures, and health concerns have been raised recently about consumption of dietary acrylamide.
Strongly reducing the activity of a single enzyme, the vacuolar acid invertase, allowed for low temperature storage of potato tubers without an accumulation of glucose and fructose. This approach was used with four potato varieties currently in commercial production and was successful in each of them. Greenhouse evaluation of the lines from these four cultivars as well as field evaluations have indicated so far that silencing of does not have negative impacts on plant growth and yield. However, large-scale field trials will be required to validate these initial observations.
In each case, when acid invertase activity was greatly reduced using molecular tools, tuber quality after low temperature storage was dramatically improved. These data clearly define a specific genetic target for improvement of potatoes that will benefit consumers and producers by improving tuber quality and the healthiness of finished potato products. Furthermore, waste caused by spoilage is likely to be reduced since tubers with decreased acid invertase activity could be stored at cooler temperatures than those from conventional varieties of potato.
Material summarized from:
Lei Wu, Pudota B. Bhaskar, James S. Busse, Ruofang Zhang, Paul C. Bethke and Jiming Jiang
Developing Cold-Chipping Potato Varieties by Silencing the Vacuolar Invertase Gene
Crop Science 2011 51:981-990
Photo provided by authors.