Sucrose degradation pathways in cold-induced sweetening and its impact on the non-enzymatic darkening in sweet potato root

Abstract This study investigated sucrose catabolism during cold-induced sweetening (CIS) and its impact on the quality of sweet potato chips of cultivars with varied levels of tolerance to cold during storage at 6 and 13 °C. In contrast to cultivar Beauregard, cultivar BRS Rubissol and BRS Cuia were cold-sensitive exhibiting intense symptoms of chilling injury at 6 °C. CIS in the sensitive cultivars BRS Rubissol and BRS Cuia was characterized by low accumulation of reducing sugar (RS), high non-reducing sugars content, low invertase activity and high sucrose synthase (SuSy) activity. In the tolerant cultivar Beauregard, the high content of RS was due to high invertases activity. In the three cultivars, the darkening of chips was more influenced by the non-reducing sugars, instead of RS. Our results suggest that SuSy was induced by cold stress in cold-sensitive cultivar, but did not contribute to the CIS in sweet potato.