Quantification of starch physicochemical characteristics in a cassava segregating population

Abstract

Culinary cassava (Manihot esculenta L.) qualities that make a variety popular are a function of starch physicochemical properties. Hence, in response to inferior root qualities in some released cassava varieties in Uganda compared to the local germplasm, a study was undertaken to examine: (i) starch physicochemical characteristics in both introduced and local varieties; and (ii) the variation in the starch properties of their F 1 progenies. The local varieties included Bao, Nyaraboke, Kakwale, and Bamunanika; and the introduced genotypes SE/95/00036, NASE 10, NASE 12, TME 5, and TME 14. Of the generated 7000 F 1 seedlings, 1077 seedlings were selected, cloned (6-8 plants per genotype) and established in a single-row trial. Root samples were collected per clone and examined for starch physicochemical properties. Considerable variations were observed in the F 1 families compared to the parental lines with weak correlations in most starch properties (r < 0.25). Amylose content ranged from 10 to 25%, with the amylose: amylopectin ratio between 1:3 and 1:9. Among the F 1 families, solubility and swelling power ranged from 1-15g100g -1 and 40-140g100 g -1 starch at 60 o C, respectively. In the parents, it ranged between 1.3-8.6 and 50-67g100g -1 starch at 60 o C, respectively. Fresh root starch yield ranged from 18 to 34%, with dry matter content varying from 19-47% in both the F 1 families and the parents. Ash and lipid content varied among the F 1 families and parents with ranges 0.05-0.29% for ash and 0.1-0.32% for lipids. In both the parents and the F 1 families, the reducing sugar and protein content ranged between 0.7-1.7 and 0.23-0.43%, respectively. These findings demonstrate: (i) existence of considerable genetic variations in starch physicochemical properties in both local and introduced cassava genotypes and their progenies, and (ii) potential utilisation of cassava starches for various applications based on the inherent differences in physicochemical characteristics.Key Words: Amylose, cassava starch, Manihot esculenta, protein, reducing sugar RÉSUMÉLes qualités qui rendent le manioc culinaire (Manihot esculenta L.) une variété populaire sont fonction des propriétés physico-chimiques de l'amidon. Ainsi, en réponse aux qualités inférieures des racines dans certaines variétés de manioc diffusées en Ouganda en comparaison avec les matériels génétiques locaux, une étude avait était menée dans le but d'examiner: (i) les caractéristiques physico-chimiques de l'amidon aussi bien dans les variétés locales que dans les variétés exotiques introduites; en plus (ii) la variation dans les propriétés de l'amidon des progenies F 1 . Les variétés locales sont Bao, Nyaraboke, Kakwale, Bamunanika et les génotypes exotiques SE/95/ 00036, NASE 10, NASE 12, TME 5 et TME 14. De 7000 F 1 plantules générées, 1077 plantules ont été sélectionnées, clonées (6-8 plants par génotype) et établies dans un essai en ligne unique. Les échantillons des racines avaient été collectées par clone et examinées pour les propriétés physico...

Use of cassava starch as gelling agent during in vitro micropropagation of banana

“…According to Morrison & Tester (1993), this yield difference is associated with genetic predisposition. The moisture content AKENA and TM 2961 extracted starch was low and it was in the range described by Nuwamanya et al (2009). These low moisture ranges are not conducive for microbial growth hence ensuring a long shelf life for the starch types.…”

“…The ash content of both cassava starches was low. According to Nuwamanya et al (2009) these ranges imply that the levels of inherent contaminants like Potassium (K) and Calcium (Ca) were very low and thus do not significantly change the basic salt formulations when supplemented in in vitro medium. The lipid content of TM 2961 was higher than that for AKENA.…”

“…Extraction of cassava starch was carried out at NCRRI by using modified Nuwamanya et al (2009) method. The roots were peeled, washed and crushed by using a mechanical grinder.…”

“…The swelling power was evaluated using Leach et al (1959) method. The pH, presence and absorbance of amylase were analysed according to Nuwamanya et al (2009). Starch ash and lipid content were determined according to Helrich (1990).…”

Characterisation and role of <i>Isoamylase1 (Meisa1</i>) gene in cassava

“…Cassava starch has wide uses in food and non-food applications based on physico-chemical characteristics (Nuwamanya et al, 2009), which are influenced by the proportions of amylopectin and amylose. Starch is a huge complex structure made of α-glucan monomer units stored in the chloroplast as transient starch and amyloplast as storage starch.…”