Glycoalkaloid and Calystegine Levels in Table Potato Cultivars Subjected to Wounding, Light, and Heat Treatments

Abstract

Potato tubers naturally contain a number of defense substances, some of which are of major concern for food safety. Among these substances are the glycoalkaloids and calystegines. We have here analyzed levels of glycoalkaloids (α-chaconine and α-solanine) and calystegines (A₃, B₂, and B₄) in potato tubers subjected to mechanical wounding, light exposure, or elevated temperature: stress treatments that are known or anticipated to induce glycoalkaloid levels. Basal glycoalkaloid levels in tubers varied between potato cultivars. Wounding and light exposure, but not heat, increased tuber glycoalkaloid levels, and the relative response differed among the cultivars. Also, calystegine levels varied between cultivars, with calystegine B4 showing the most marked variation. However, the total calystegine level was not affected by wounding or light exposure. The results demonstrate a strong variation among potato cultivars with regard to postharvest glycoalkaloid increases, and they suggest that the biosynthesis of glycoalkaloids and calystegines occurs independently of each other.

Effect of genotype, flesh colour and environment on the glycoalkaloid content in potato tubers from integrated agriculture

“…The content of glycoalkaloids in the flesh of tubers varied for α-solanine from 10.39 to 77.01 mg/kg FM, α-chaconine from 19.14 to 90.76 mg/kg FM and TGA 33.69 to 167.77 mg/kg FM (Table 2). Importantly, the TGA content did not exceed 200 mg/kg FM for any cultivar (equivalent to roughly 1000 mg/kg dry matter, assuming a water content of 80%), which is considered to be hazardous to human health (Tajner-Czopek et al 2012, Petersson et al 2013. The TGA contents found by us are in line with other literature data, which also indicates a significant variability in TGA ranges among cultivars.…”

“…The TGA contents found by us are in line with other literature data, which also indicates a significant variability in TGA ranges among cultivars. Valcarcel et al (2014) indicated a range from 4 to 957 mg/kg dry matter (DM), Friedman et al (2003) from 5 to 592 mg/kg DM, Deusser et al (2012) from 7 to 466 mg/kg DM and Petersson et al (2013) indicated normal ranges between 5 and 100 mg/kg FM.…”

“…In contrast, in experiments provided by Gugała et al (2017), weather conditions in experimental years had an insignificant influence on GA levels in potato tubers. It is difficult to determine the exact causes of increased GA accumulation in tubers, but many authors agree that the synthesis of GA is related to stress in general, during both growth and storage (Petersson et al 2013, Valcarcel et al 2014, Mekapogu et al 2016. Papathanasiou et al (1999) reported that heat stress increases the glycoalkaloid content, with various results reported for low temperatures.…”

Variation for Tuber Greening in the Diploid Wild Potato Solanum Microdontum

“…Cultivars vary for light-induced glycoalkaloids (Grunenfelder et al 2006b). Some may increase eight-fold after illumination (Petersson et al 2013), while Percival (1999) identified the cultivar Maris Piper as being insensitive to lightinduced glycoalkaloid accumulation. Attempts have been made to use greening as a predictor of glycoalkaloids within particular genotypes (Dickie 2004).…”

Biotech Potatoes in the 21st Century: 20 Years Since the First Biotech Potato

“…Wounding and light exposure are known to affect glycoalkaloid content, which could lead to levels beyond the threshold of 20 mg per 100 g fresh weight (Petersson et al 2013), the level considered safe for human consumption (Smith et al 1996). Many wild species of potato naturally produce high levels of glycoalkaloids (Gregory et al 1981), leading to a need to monitor glycoalkaloid content when introducing other traits from these species.…”