Potato Glycoalkaloids: Chemistry, Analysis, Safety, and Plant Physiology

Abstract

Potatoes, members of the Solanaceae plant family, serve as a major, inexpensive food source for both energy (starch) and good-quality protein, with worldwide production of about 350 million tons per year. U.S. per capita consumption of potatoes is about 61 kg/year. Potatoes also produce potentially toxic glycoalkaloids, both during growth and after harvest. Glycoalkaloids appear to be more toxic to man than to other animals. The toxicity may be due to anticholinesterase activity of the glycoalkaloids on the central nervous system and to disruptions of cell membranes affecting the digestive system and other organs. The possible contribution of glycoalkaloids to the multifactorial aspects of teratogenicity is inconclusive. Possible safe levels are controversial; guidelines limiting glycoalkaloid content of potato cultivars are currently being debated. This review presents an integrated, critical assessment of the multifaceted aspects of the role glycoalkaloids play in nutrition and food safety; chemistry and analysis; plant physiology, including biosynthesis, distribution, inheritance, host-plant resistance, and molecular biology; preharvest conditions such as soil composition and climate; and postharvest events such as effects of light, temperature, storage time, humidity, mechanical injury, sprouting inhibition, and processing. Further research needs are suggested for each of these categories in order to minimize pre- and postharvest glycoalkaloid synthesis. The overlapping aspects are discussed in terms of general concepts for a better understanding of the impact of glycoalkaloids in plants and in the human diet. Such an understanding can lead to the development of potato varieties with a low content of undesirable compounds and will further promote the utilization of potatoes as a premier food source for animals and humans.