Composition and properties of starches extracted from tubers of different potato varieties grown under the same environmental conditions

Twelve commercially relevant potato cultivars were grown in a field plot in Perthshire (UK) in 1996. Starches were extracted from these tubers and their physico-chemical properties were investigated with a particular focus on aspects of granule order and corresponding gelatinisation characteristics. There was little variation in (average) granule diameter (21.4 +/-1.6 mum), amylose content (28.7 +/- 1.9%) or phosphorus (0.54 +/- 0.16 mug mg(-1)) content. Structural elements of amylopectin were essentially constant in terms of unit distributions and chain lengths (average DP 28 +/- 2) with long (F-1) and short (F-2) chains with average DP of 56 +/- 2 and 19 +/- 1, respectively. The structures of the (debranched) beta-limit dextrins of the amylopectin molecules, were also very similar with the average DP of the two major fractions (F-1beta and F-2beta) being 48 +/- 3 and 37 +/-2, respectively. Peak gelatinisation temperatures (T-p) and enthalpy (DeltaH) were also correspondingly similar (63.2 degreesC +/- 1.2 and 18.6 degreesC +/- 0.8, respectively). The constancy of physico-chemical properties for these starches is in marked contrast to variation in different parameters induced by environmental factors, especially growth temperature. (C) 2003 Elsevier Science Ltd. All rights reserved.