Glycoalkaloid Concentration of Potato Tubers Following Exposure to Daylight

Abstract

The total glycoalkaloid concentrations in white‐ (cv Pentland Hawk), pink‐ (cv Kerrs Pink) and red‐ (cv Desiree) skinned potato tubers were measured following 21 days exposure to daylight using high‐performance liquid chromatography. Average daytime irradiance during this period was 232 μmol m−2 s−1. Regardless of cultivar, glycoalkaloid concentrations were increased after light exposure compared with initial concentrations. Glycoalkaloid concentrations fluctuated with time and continuous accumulation of glycoalkaloids with time was not demonstrated. Glycoalkaloid synthesis was maximal in the sequence cv Kerrs Pink<cv Pentland Hawk<cv Desiree. Exposure to daylight altered the ratio of α‐chaconine: α‐solanine in tubers of cv Desiree but not those in cv Pentland Hawk and Kerrs Pink. Glycoalkaloid concentrations in all cultivars were higher than the recommended food safety level, this was reached after 8 days in cv Kerrs Pink and Desiree and at 13 days in Pentland Hawk. The implications of these results in terms of food safety are discussed.

Effect of light and temperature on the formation of glycoalkaloids in potato tubers

“…A similar behaviour was observed by Percival, Dixon, and Sword (1996) for the cultivars Kerrs Pink, Pentland Hawk and Desiree. Although an increase of the TGA level was verified after exposure of the tubers to natural light for 21 days, the authors reported that the TGA contents fluctuated during the experiment, with no continuous accumulation of these compounds by the potato varieties studied.…”

Extraction and determination of the potato glycoalkaloidα-solanine in soil

“…All these factors usually increase the glycoalkaloid concentration in the tubers. In tubers exposed to daylight for 21 days, the content increased 3.6-10 times depending on the cultivar [20]. Mechanical injuries doubled the content [21] and pests caused a 50% increase [22].…”

“…After 0, 7, 17, and 36 days, three subsamples were taken, and the content of -solanine was determined as described above. Potato tubers of the cultivar Sava were placed in daylight at room temperature for about 3 weeks to induce the -solanine production [20]. Potato tubers were finely grated by a juicer (Braun MP-80 Juicer), separating the potato juice and the potato pulp.…”

Effect of bruising on the total glycoalkaloid and chlorogenic acid content of potato (Solanum tuberosum) tubers of five cultivars

“…Such stresses include, principally, light exposure (Dale et al 1993 ;Percival et al 1996) and tuber damage. Tuber damage during harvest and store operations can result in various symptoms including bruising, shatter cracks and splits.…”