Glycoalkaloids in commercial potato varieties traded in Nairobi, Kenya

Abstract

Background: Glycoalkaloids are naturally occurring toxins in potatoes which, at high levels, pose food safety concerns to consumers. Their concentrations in potatoes are dependent on postharvest handling, variety and stress factors tubers are exposed to. Limited information, however, exists on levels of glycoalkaloids in commercially traded potato tubers in Kenya. The current study sought to determine the glycoalkaloid levels in potatoes traded in Nairobi, Kenya.  Methods: Three potato varieties, Shangi, Dutch Robjin and Royal sold in open-air markets and supermarkets were randomly sampled and their glycoalkaloid levels determined by high-performance liquid chromatography. Results: The levels varied significantly (p<0.05). The Shangi variety had the highest glycoalkaloids with a mean of 410.35 mg kg-1 dry weight with samples from supermarkets having the highest levels (550.8 mg kg-1). The same variety from open air markets averaged 382.26 mg kg-1 dry weight compared to the Dutch Robjin (129.2 mg kg-1 dry weight) and Royal variety (98.2 mg kg-1 dry weight) which had the least levels of glycoalkaloids. Conclusions: The levels in sampled tubers did not exceed the recommended levels of 1000 mg/kg on dry weight basis and, therefore, consumption of these potatoes would not raise safety concerns. There is, however, a need to ensure that marketing of tubers is carried out under conditions that minimize occurrence of glycoalkaloids, especially for the Shangi variety, which is the most common in the markets but had relatively high levels of these toxins. There is also a need to educate marketers on the need for proper storage and handling of potatoes during marketing to avoid risk of accumulation of glycoalkaloids.