Identification of metabolites associated with boiled potato sensory attributes in freshly harvested and stored potatoes

Abstract
Modern potato breeding programmes have to balance agronomic and consumer preferences, as they seek to develop high yielding and nutritious potatoes that are tolerant to abiotic/biotic stresses. The recent focus on consumer preference has generated sensory data to assess potato flavour intensity, umami, sweetness, acidity, bitterness and mealiness in a panel of 60 cultivated and four wild potato accessions. The potato tubers were assessed immediately after harvest and after a five-week cold storage period. The cultivated accessions included diploid landraces of S. tuberosum L. Andigenum groups Phureja and Stenotonum, diploid hybrids of these, and advanced tetraploid breeding lines. The wild accessions represented tuber-bearing Solanum species, implicated in potato domestication. Sensory data highlighted 20 advanced breeding lines that were relatively weak in potato flavour, sweetness and umami before storage, but increased to the intensities of the landrace and hybrids bred from them after storage. The data observed 42 metabolites which were significantly different (~3-fold) between storage times and associated with sweetness, umami, bitterness and acidity tastes. A comparison to potatoes with high potato flavour emphasised that lower levels of specific metabolites associated with sweetness (e.g. glucose, fructose, glycine and serine), acidity (oxalic, ascorbic and citric acid) and umami (aspartic acid) were related to a higher rating for potato flavour. This corroborates the hypothesis, that perception of sensory traits is based on a complex metabolic composition in potato tubers. This data also indicates that metabolomic analysis can play an important role in augmenting future breeding programmes considering consumer traits.