Discerning intra-tuber differences in textural properties in cooked Solanum tuberosum group Tuberosum and group Phureja tubers

Abstract

The method developed is valid and consistent for assessing textural differences within potato germplasm. The relationship between PME activity and enhanced resistance to fracture suggests that PME may modulate pectin cohesiveness, perhaps through increasing Ca(2+)-bridges, to provide greater resistance to fracture.

Potato tuber pectin structure is influenced by pectin methyl esterase activity and impacts on cooked potato texture

“…The potato samples were boiled for 10 min and the wedge fracture test (as outlined by Vincent et al , 1991) was used as described by Ross et al (2010). Briefly, using an acrylic wedge descending through the cooked tuber cube at 5 mm min −1 , two measurements were recorded for each sample; work done is the energy required to penetrate to 10 mm while peak force is the maximum force required for the wedge initially to cut and then force the tissue apart and propagate a crack in the cube ahead of the wedge.…”

“…The relative importance of the different factors involved is not yet clear. Several studies have described potato germplasm that produces tubers with markedly different textural properties (Van Marle et al , 1994; Ducreux et al , 2008; Ross et al , 2010). In particular, members of the Solanum tuberosum group Phureja (Phureja) have been identified which exhibit a boiled tuber texture described as extremely floury or crumbly (De Maine et al , 1993, 1998).…”

“…In particular, members of the Solanum tuberosum group Phureja (Phureja) have been identified which exhibit a boiled tuber texture described as extremely floury or crumbly (De Maine et al , 1993, 1998). The cooking time of Phureja tubers is generally in the order of half that taken for typical Solanum tuberosum group Tuberosum (Tuberosum) tubers at the same developmental stage (Ducreux et al , 2008; Ross et al , 2010). …”

“…Good correlations between the wedge fracture and panel sensory tests for a range of different food types were demonstrated. More recently, the method has been developed to assess cooked potato tuber texture (Ross et al , 2010) and it was demonstrated that tubers from the Phureja group, when cooked (by steaming or boiling) gave significantly lower peak force and work done values during fracture than typically observed for those from Tuberosum. Apart from the stem end of the tuber, which is enriched in vascular tissues, there was little variation in tuber textural properties throughout the rest of the tuber.…”

“…The much higher ( c . 10-fold) expression level of the PEST1 gene and total PME activity in Tuberosum tubers may underpin changes in pectin structure and contribute to the differences in textural properties compared with Phureja (Ross et al , 2010). In all plants studied to date, several PME genes are expressed (reviewed in Pelloux et al , 2007).…”