In-season heat stress compromises postharvest quality and low-temperature sweetening resistance in potato (Solanum tuberosum L.)

Abstract

The effects of soil temperature during tuber development on physiological processes affecting retention of postharvest quality in low-temperature sweetening (LTS) resistant and susceptible potato cultivars were investigated. 'Premier Russet' (LTS resistant), AO02183-2 (LTS resistant) and 'Ranger Russet' (LTS susceptible) tubers were grown at 16 (ambient), 23 and 29 °C during bulking (111-164 DAP) and maturation (151-180 DAP). Bulking at 29 °C virtually eliminated yield despite vigorous vine growth. Tuber specific gravity decreased as soil temperature increased during bulking, but was not affected by temperature during maturation. Bulking at 23 °C and maturation at 29 °C induced higher reducing sugar levels in the proximal (basal) ends of tubers, resulting in non-uniform fry color at harvest, and abolished the LTS-resistant phenotype of 'Premier Russet' tubers. AO02183-2 tubers were more tolerant of heat for retention of LTS resistance. Higher bulking and maturation temperatures also accelerated LTS and loss of process quality of 'Ranger Russet' tubers, consistent with increased invertase and lower invertase inhibitor activities. During LTS, tuber respiration fell rapidly to a minimum as temperature decreased from 9 to 4 °C, followed by an increase to a maximum as tubers acclimated to 4 °C; respiration then declined over the remaining storage period. The magnitude of this cold-induced acclimation response correlated directly with the extent of buildup in sugars over the 24-day LTS period and thus reflected the effects of in-season heat stress on propensity of tubers to sweeten and lose process quality at 4 °C. While morphologically indistinguishable from control tubers, tubers grown at elevated temperature had different basal metabolic (respiration) rates at harvest and during cold acclimation, reduced dormancy during storage, greater increases in sucrose and reducing sugars and associated loss of process quality during LTS, and reduced ability to improve process quality through reconditioning. Breeding for retention of postharvest quality and LTS resistance should consider strategies for incorporating more robust tolerance to in-season heat stress.

Low oxygen storage modulates invertase activity to attenuate cold-induced sweetening and loss of process quality in potato (Solanum tuberosum L.)

“…The high affinity of SP for small linear maltodextrins and low affinity for high molecular weight branched chain glucans indicate a downstream role (if any) in the catabolism of starch in leaves. Similarly, silenced SPL did not attenuate total sugar (Suc + RS) buildup during LTS of potato, suggesting the plastidic isoform is not required for cold-induced starch catabolism; however, the isoform was induced in non-SPL-silenced heat-stressed tubers undergoing LTS (Knowles, unpublished shown by Zommick et al (2014a). In addition to a potential downstream role in starch catabolism, plastidic SP can participate in starch synthesis and functions at relatively low temperatures (Fettke et al 2010;2012).…”

“…French fry process quality was also evaluated at each sampling date using methods detailed in Zommick et al (2014a). French fry planks (9.5-mm-thick x 2.9-cm-wide x length of tuber) were cut longitudinally along the apical to basal axis from the larger half (see above) of each tuber (one plank per tuber) and the 12 planks representing a cultivar from a particular treatment chamber were collectively fried for 3.5 min at 191 o C in vegetable oil.…”

“…Tuber carbohydrates were extracted from lyophilized tissue by modifying the methods of Zommick et al (2014a). Lyophilized tissue (250 mg) was extracted by vortexing with 3 mL 60% (v/v) methanol in triethanolamine·HCl (TEA) buffer (30 mM, pH 7.0).…”

Factors Influencing the Acrylamide Content of Fried Potato Products

“…The transformation of starch into reducing sugars such as glucose and fructose occurs in potato tubers stored at low temperatures (Isherwood, 1973). This phenomenon has been studied extensively over the years (Burton, 1965;Ewing, 1974;Sowokinos, 1990;Hertog et al, 1997;Edwards et al, 2002;Zommick et al, 2014). The accumulation of reducing sugars at low temperature is referred to as "low temperature sweetening (LTS) (Edwards et al, 2002;Zommick et al, 2014) and was noted to occur after prolonged storage of potatoes at 10℃ (Burton, 1965) or below 8℃ (Agle and Woodbury, 1968).…”

Allele Variability of Amylase Inhibitor Gene Ai in Potato Varieties and Lines

“…При высокотемпературной термической обработке происходит взаимодействие редуцирующих сахаров с -аминокислотами и образование акриламида, являющегося канцерогеном, а также ухудшаются вкусовые качества (19)(20)(21). На процесс холодового осахаривания влияют такие факторы, как зрелость клубней, механические повреждения, биотический и абиотический стресс (20,22).…”