Genetic diversity of organoleptic properties in water yam (Dioscorea alata L)

Abstract

Improving the food quality of yams (Dioscorea spp) is an ongoing challenge to yam breeders and researchers. Forty accessions of D alata were evaluated for the suitability of their tubers for the preparation of two dominant food forms (boiled and pounded) as part of an effort to identify potential parents for use in genetic improvement. Trained panellists were presented with randomised, replicated and coded samples of boiled yam tuber pieces and asked to rate them for mealiness, colour, wetness, softness and taste. The sensory attributes considered for pounded yam (dough from boiled and pounded tubers) were consistency, colour, sheen, smoothness, stickiness, elasticity and hardness. Ratings were based on hedonic scales. Cluster analysis revealed groupings of accessions into eight and nine similarity clusters for boiled yam and pounded yam respectively. The mean scores for general preference were regressed on individual attribute scores. Mealiness, colour and taste were important in the general preference for boiled yam. Consistency, colour and stickiness determined the general preference for pounded yam. Of the accessions, 67% were identified as being suitable for preparation as a boiled vegetable, while 55% were assessed to be good for pounded yam, based on the respective quality attributes evaluated.

Physico-chemical characterisation of yam (Dioscorea alata L.) tubers from Vanuatu

“…Egesi et al (2003) evaluated 40 accessions for the suitability of their tubers for the preparation of boiled and pounded yams. Ratings were based on hedonic scales and the mean scores for general preference were regressed on individual attribute scores.…”

“…In the Pacific, although some preliminary work has been done at the inter-specific level (Bradbury and Holloway 1988), the lack of information on the variation within D. alata hinders its prospective utilisation as a high quality exportable vegetable. Egesi et al (2003) studied the extent of genetic diversity existing for organoleptic properties in 40 water yam varieties cultivated in Nigeria. Two thirds of their accessions were identified as being suitable for boiled yam, while more than half of these accessions were good for pounded yam.…”

Dioscorea

“…The passport or characterization data of most of the accessions are also incomplete and duplicates are yet to be eliminated. Yam germplasm has been characterized for morphological characters (Dansi et al 1998(Dansi et al , 1999(Dansi et al , 2000a, physico-chemical characteristics (Lebot et al 2006), organoleptic properties (Egesi et al 2003), soluble tuber protein profiles (Ikediobi and Igboanusi 1983), or isozyme patterns (Lebot et al 1998;Dansi et al 2000a;Mignouna et al 2002a). Similarly, use of molecular markers such as amplified fragment length polymorphism (AFLP), RAPD and simple sequence repeat (SSR) markers have also been reported Malapa et al 2005;Egesi et al 2006;Scarcelli et al 2006;Tamiru et al 2007;Tostain et al 2007) in diversity studies of yams.…”

Determination of relevant sensory properties of pounded yams (Dioscorea spp.) using a locally based descriptive analysis methodology

“…Theses studies especially concerned the agronomic potential of yam varieties (Pistorius, 1992), the intensive farming systems (Olojede, Ohiri, & Chukwu, 2001), the techniques for reducing tubers post-harvest losses under fresh (Tschannen et al, 2002) and dried forms (Akissoe et al, 2001), and the characterizations of physicochemical and functional properties of yam tubers (Otegbayo, Aina, Asiedu, & Bokanga, 2005). Few data (Egesi, Asiedu, Egunjobi, & Bokanga, 2003;Onayemi, 1985) exist on the perception of the quality of processed yam using analytical tools, allowing to generate an extended array of sensory descriptors, responsible for consumers preference. When an analytical method was used as sensory texture profile technique (Onayemi, 1985), the attributes developed were not sufficiently defined as relevant for the expectations of the quality yam by consumers.…”