I. L. Batey

Sources of Variation for Starch Gelatinization, Pasting, and Gelation Properties in Wheat

ABSTRACT The starch of wheat (Triticum aestivum L.) flour affects food product quality due to the temperature-dependent interactions of starch with water during gelatinization, pasting, and gelation. The objective of this study was to determine the fundamental basis of variation in gelatinization, pasting, and gelation of prime starch derived from seven different wheat cultivars: Kanto 107, which is a partial waxy mutant line, and six near-isogenic lines (NILs) differing in hardness. Complete pasting curves with extended 16-min hold at 93°C were obtained using the Rapid Visco Analyser (RVA). Apparent amylose content ranged from 17.5 to 23.5%; total amylose content ranged from 22.8 to 28.2%. Starches exhibited significant variation in onset of gelatinization. However, none of the parameters measured consistently correlated with onset or other RVA curve parameters that preceded peak paste viscosity. Peak paste viscosity varied from 190 to 323 RVA units (RVU). Higher peak, greater breakdown, lower final visc...

Optimization of Rapid-Visco Analyser test conditions for predicting Asian noodle quality

ABSTRACT A variety of Rapid-Visco Analyser (RVA) operating conditions have been tested with starch, flour, and wholemeal for predicting the quality of wheats for the manufacture of Japanese white-salted noodles. Using starch as the substrate, an initial temperature of 60°C has been found to be optimum, and the best heating time from this initial temperature to the peak temperature of 95°C was ≈6 min. Significant correlations were found between peak viscosity of starch pastes and noodle quality under these operating conditions. For flour and wholemeal samples, the correlations were not as high as for isolated starch. The correlations with wholemeal or flour and noodle quality could be improved by the addition of α-amylase inhibitors. Measuring RVA viscosity of flour or wholemeal in the presence of silver nitrate gave viscosities which showed highly significant correlations with noodle quality. These correlations were similar to those obtained with isolated starch. It appears that the improvement is due to ...

Effects on pasting viscosity of starch and flour from different operating conditions for the Rapid Visco Analyser

ABSTRACT Three wheat flours, three wheat starches, a regular maize starch and a waxy maize starch were subjected to a number of different RVA profiles. Five different initial temperatures were used, 40, 50, 55, 60, and 65°C, with different initial holding times (0–3 min), heating times (2fl–10 min), holding times at 95°C (0–6 min), cooling times (2–6 min), and final hold times (0–10 min) being applied. A range of final temperatures of 30–60°C was also utilized. Significant variations in viscosity were observed with these conditions, particularly in wheat starch and flour. The most important parameters causing these variations were the initial temperature, the heating rate, and the final holding time. Short initial holding times also resulted in a wider spread of values for peak viscosity although there was little effect on the mean value and no significant effect on the holding strength or final viscosity. The final temperature was also important in that lower temperatures gave more viscous gels. Provided...

Effect of source and proportion of waxy starches on pasta cooking quality

ABSTRACT Starches from the endosperm of three types of total-waxy cereals (bread wheat, maize, and barley) were used in reconstitution studies of durum wheat semolinas to investigate the effect of waxy starch on pasta cooking quality. The chemical composition and the pasting and gelatinization properties of the starches used in this study were evaluated to define the functional properties of each waxy starch. The rheological properties of dough semolinas were evaluated by small-scale mixograph. Spaghetti was prepared using a small-scale pasta extruder and its cooking quality was assessed using a texture analyzer. Cooked pasta firmness, resilience, and stickiness were measured. The substitution of semolina starch with waxy starches from different sources changed the functional properties of dough and their pasta quality. A decrease in firmness was detected in all the semolinas reconstituted with waxy starches. An increase in stickiness was found when semolinas with waxy starch from wheat were evaluated. No...

Genetic mapping of commercially significant starch characteristics in wheat crosses

Starch properties were measured on the doubled haploid progeny of 2 crosses, one between Cranbrook and Halberd and the other between CD87 and Katepwa. Properties studied included starch peak and final viscosity measured by Rapid Visco Analyser, starch granule size distribution measured by laser light scattering, starch gelatinisation temperature by differential scanning calorimetry, and flour swelling volume. In the Cranbrook × Halberd cross (samples from 2 environments), a highly significant quantitative trait locus (QTL) was located on chromosome 4A for both starch peak viscosity and starch/flour swelling volume, centred around the Wx-B1 locus. In previous studies, this locus has been found to be linked to Japanese noodle quality. The increases in starch peak viscosity and flour swelling volume are derived from the Halberd parent, consistent with the fact that Halberd is null for the Wx-B1 locus on chromosome 4A and is missing the respective granule-bound starch synthase protein, whereas Cranbrook is a wheat line carrying the normal 3 Wx loci. The final starch viscosity also showed an association with the Wx-B1 locus. In the CD87 × Katepwa cross, the progeny showed an association between peak viscosity and a marker on chromosome 7A. This appeared to be near the Wx-A1 locus. In some experiments, flour viscosity showed a highly significant QTL on chromosome 7B, apparently at the same locus as the late maturity α- amylase derived from the Cranbrook parent. Starch gelatinisation onset temperature indicated a significant QTL on chromosomes 2B and 7A (LOD = 2.58 and 3.66, respectively, in interval analyses). Starch gelatinisation peak temperatures indicated a QTL on chromosome 7A, which, although not in the significant (P = 0.05) class based on regression analyses, indicated a LOD score of 3.06 in interval analyses. Heat of gelatinisation (∆H) indicated a suggestive QTL (LRS = 14.5 with a threshold of 14.7 for P < 0.05, LOD = 2.65 for interval analysis), on chromosome 4A, at the Wx-B1 locus with an increased effect coming from the Halberd parent. The A:B granule ratio analysis indicated a significant QTL on chromosome 4B, but this was not observed in all environments and may be due to the fact that the QTL corresponded to the position of a major QTL controlling plant growth. Additional keywords: viscosity, gelatinisation, granule size, genetics, quantitative traits. I M S. h C. K. . A Genetic mapping ofstarch characteristics

Gliadin genes contain heat-shock elements: Possible relevance to heat-induced changes in grain quality

Etat de la recherche sur la biosynthese des proteines du choc thermique dans le ble soumis a une temperature elevee lors de la culture. Mise en evidence de sequences homologues dans ces proteines et dans la gliadine, ainsi que des elements du choc thermique dans 2 genes gliadine. Relation avec la teneur en gliadine et en glutenine

Contribution of the Chemical Structure of Wheat Starch to Japanese Noodle Quality

Wheat starch has been completely digested with bacterial α-amylase, and the pattern of oligosaccharides obtained from this digestion varies with starches from different wheat varieties. Wheat varieties of good Japanese noodle-making quality (based on sensory testing) give relatively small amounts of oligosaccharides with a degree of polymerisation (DP) of 5 or greater, while varieties of poor noodle-making quality give much greater amounts of these larger oligosaccharides. There is a significant negative correlation between the amount of DP5 oligosaccharide and noodle eating quality. The correlation between the amount of this oligosaccharide and starch paste viscosity was much smaller. The size of the HPLC peak corresponding to this oligosaccharide may be used as a rapid method of screening for noodle-making quality. Because oligosaccharides of greater than DP4 should have at least one branch point, the results suggest that the structure of the amylopectin in starch of good noodle-making wheats has relatively few branch points close together. Amylose also appeared to be important for noodle quality. The optimum amylose content seemed to be about 22% for good quality noodles, with starch of higher or lower amylose content coming from flour of lower noodle-making quality. Factors other than amylose content must contribute to noodle quality, as some flours of relatively poor noodle quality also contained close to the optimum amount of amylose.

Protein and Starch Properties of Some Tetraploid Wheats

ABSTRACT The tetraploid relatives (subspecies) of commercial durum wheat (Triticum turgidum L. subsp. turgidum conv. durum (Desf.) MacKey) offer a source of economically useful genes for the genetic improvement of durum cultivars. Thirty-two accessions, representing five different subspecies: var. durum (13 accessions), polonicum (7), persicum (3), turanicum (5), and turgidum (4) were grown at Tamworth, Australia, in 1997 and 1999. These accessions were compared with three durum cultivars: Wollaroi and Kamilaroi (in both years) and Yallaroi (in 1998 only). In this study, the glutenin subunit composition and molecular weight distribution, together with starch properties of these accessions, were studied. A much wider range in both the glutenin subunit composition and the starch RVA paste viscosities and gelatinization profiles were found in the accessions compared with the cultivated durum wheats. Most of the accessions had lower gluten strength and the presence of poor quality LMW alleles, and low proport...

Small-Scale Reconstitution of Durum Semolina Components

ABSTRACT Pasta prepared by extrusion from 25 g of semolina has been compared with that made from a standard laboratory extruder and found to have similar quality. Durum semolina was fractionated into its starch, gluten, water soluble, and residue fractions. The freeze-dried components were reconstituted and the properties of the reconstituted semolina (ReSem) have been measured. Examination using a 2 g-mixograph and micro-extension tester has shown that ReSem behaves similarly to the original semolina. ReSem and semolina were made into pasta using a small-scale pasta extruder and were of comparable cooking quality. The fractionation and reconstitution of durum semolina on this scale is a useful technique to evaluate the contribution of semolina components to pasta quality.

Effect of storage of adzuki bean (Vigna angularis) on starch and protein properties

Differential scanning calorimetry was used to evaluate the effect of storage at 10degreesC, 20degreesC and 30degreesC, and 40% and 65% relative humidity (RH) on adzuki bean starch gelatinisation and protein denaturation temperatures. Storage for 6 months at an elevated storage temperature (30degreesC) caused increases in the starch gelatinisation onset temperature (T-o) and gelatinisation peak temperature (T-p) for both Bloodwood and Erimo varieties. Storage at 40% RH resulted in higher T-o and T-p values than storage at 65% RH. The T-o of starch from Bloodwood and Erimo beans stored for up to 1.5 months at 10degreesC and 65% were similar to those of fresh beans. The changes in the salt-soluble protein component were less clear cut than those of the starch. Nonetheless, protein extracted from beans stored at 40% RH exhibited significantly lower T-o and T-p values compared with those stored at 65% RH. This indicates some destabilisation of the protein at the higher RH. These results suggest that detrimental changes occur in starch and, to a lesser extent protein, of adzuki beans stored under unfavourable conditions. On the basis of these results, the best storage conditions to maintain the characteristics of fresh beans are low temperatures (e.g. 10degreesC) and high RH (e.g. 65%)