Understanding mechanisms and identifying markers for the onset of senescent sweetening of potato (Solanum tuberosum)

Storage potential of processing potatoes is often terminated prematurely by the unpredictable onset of senescent sweetening. The condition, characterised by a rise in reducing sugar content (fructose and glucose), results in darkening of chips and crisps increasing the risk of acrylamide formation through the Maillard reaction. Information is lacking on biochemical mechanisms that trigger senescent sweetening and better predictive methodologies for growers/processors are urgently needed. This study aims to understand mechanism(s) underpinning senescent sweetening and develop predictive tools. Commercial varieties Lady Rosetta (‘susceptible’ to sweetening) and VR 808 (able to maintain a ‘stable’ sugar profile), were planted from common seed tubers at 3 UK locations (Norfolk, Shropshire, Yorkshire) during the 1st year, Norfolk (Norwich) during the 2nd year and Yorkshire during the 3rd year of the study. During the first two years Pentland Dell and Russet Burbank, were included in the trial as additional material that provided contrasting profiles of sugar accumulation during storage. During the 3rd year P. Dell tubers chitted (250 days) and non-chitted were added to the trials to determine the influence in aged seed in Senescent Sweetening. Cured and CIPC treated tubers were stored at 10°C (Sutton Bridge Crop Storage Research) and sampled every 6-8 weeks for tuber quality (NRI) for physiological changes during long-term storage at 10°C. Effects of calcium (Ca) in storage potencial were studied in tubers from a fertilization trial, and its effects on dormancy break/sprout growth were tested as well. Duration of storage had the largest impact on sugar accumulation and respiration. Significant varietal differences effected senescent sweetening: respiration and sugar accumulation were higher in L. Rosetta and P. Dell than in VR 808 and R. Burbank. Comparison of fluctuations and the abundance of ROS activity captured by staining help to link possible mechanisms for a decrease in vitamin C during 10°C storage. Quantifying changes in amyloplast integrity, water dikinases activity and ROS activity could help with the development of diagnostic markers for predicting changes in tuber health and be used in the longer term for genetic marker development. It was concluded that Ca regulation had a significant impact in senescent sweetening.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Greenwich

Year dc:date.issued

2017

Author dc:creator

• Goncalves Da Silva Carvalho, Cláudia

Advisors dc:contributor.advisor

• Colgan, Richard
• Rees, Deborah

• SB Plant culture

Language dc:language

en