Late sowings may represent a way of increasing pasta cooking quality whenever they place grain filling under thermal conditions able to increase protein percentage, although the accompanying decrease in yield may represent a drawback in environments prone to drought stress during ripening. The lower protein percentages of modern durum wheat cultivars under conventional sowing times results in a lower pasta cooking quality despite higher gluten strength.

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Woods, S. M. 2003. The effect of extra-strong gluten on quality parameters in durum wheat. Can. J. Plant Sci. 83: 525-532. Durum wheat (Triticum durum L.) cultivars with extra-strong gluten characteristics have become a unique quality type preferred by several domestic and international pasta processors. Durum genotypes with extra-strong gluten characteristics were compared to conventional gluten strength types to determine the relative levels of gluten strength and the importance of this characteristic in pasta quality. All extra-strong genotypes had similar gluten index levels that were significantly greater than cultivars traditionally grown in western Canada. For improved endproduct texture, the level of gluten strength appeared to be less important than protein content and wet gluten weight, which were the variables most closely linked to spaghetti viscoelasticity. The general positive relationships between texture and protein content of high temperature dried spaghetti followed the findings of previous studies. However, extra-strong gluten genotypes with lower protein content could not match the superior texture characteristics obtained with higher protein conventional strength cultivars. When dried at 70°C, pasta texture, measured as viscoelastic properties, was dependent on gluten strength rather than protein content, so the higher gluten strength types had an advantage even at lower protein levels. While the relationship between gluten strength and texture of low temperature dried products has been noted previously, this study shows that this relationship is somewhat dependent on having a range of gluten strength types present. Although there was a positive relationship between spaghetti viscoelasticity and protein content, and between pasta disc viscoelasticity and gluten strength, there appeared to be a negative relationship between gluten strength and protein quantity factors. Scatter plot matrices of the means indicated the negative correlation was likely due to clustering of similar genotypes, but that a positive relationship was apparent within the extra-strong gluten types. ) à gluten extra-fort dont ils apprécient la qualité particulière. Les auteurs ont comparé les génotypes à gluten extra-fort aux génotypes ordinaires en vue d'établir la résistance relative du gluten et l'importance de cette propriété pour la fabrication de pâtes alimentaires. Les génotypes à gluten extra-fort ont un indice semblable pour le gluten, indice sensiblement supérieur à celui des variétés habituellement cultivées dans l'ouest du Canada. La résistance du gluten semble moins intervenir dans la texture du produit fini que la teneur en protéines et le poids du gluten humide, ces deux variables étant les plus étroitement associées à la viscoélasticité du spaghetti. Des études antérieures avaient déjà illustré le lien généralement positif entre la texture et la teneur en protéines du spaghetti séché à haute température. Néanmoins, les génotypes à gluten extra-fort et à plus faible teneur en protéines ne reproduisent pas ...

Fu, B. X., Hatcher, D. W. and Schlichting, L. 2014. Effects of sprout damage on durum wheat milling and pasta processing quality. Can. J. Plant Sci. 94: 545–553. Due to concerns over the unusual sprouting problem observed in the 2010 harvest of Canada Western Amber Durum Wheat (CWAD), it was deemed necessary by the industry to investigate and determine if appropriate tolerances for sprout damage were in place, particularly for No. 3 CWAD. More information on the impact of visually assessed sprout damage on durum quality is needed to better define the associated acceptable level of falling number (FN). To this end, two different samples of CWAD were sourced for this project: a No. 1 CWAD (FN 479 s) and a No. 5 CWAD (FN 68 s) degraded primarily due to sprout damage. A total of 19 samples were used in the study, i.e., a series of eight composite samples prepared by blending the No. 1 with increasing amounts of No. 5, as well as the two control extremes. The FNs of the blends were well characterized, displaying an incremental decrease of ∼50 s with increasing sprout damage. Each wheat sample was milled in duplicate. The resulting semolina was analyzed for ash, pigment, pigment loss, yellowness (b*), and speckiness. Protein content, gluten index and alveograph parameters were also evaluated. The semolina was made into spaghetti for colour measurement and texture evaluation. Results indicated that there was no change in ash content, pigment or semolina b* value even at 50% blend (FN 101 s). However, a noticeable increase in total speck count and the number of dark specks in the semolina were detected once the blending ratio reached the 35% level (FN 208 s). The increase in speck count was largely due to mildew associated with the No. 5 CWAD sample. The influence of sprout damage on gluten strength was minimal at all levels of blending. A significant increase in spaghetti redness (a*) was detected in blends with 25% (FN 152 s) or more of No. 5 CWAD. A decline in spaghetti brightness (L*) was also observed when transitioning from the 15% blend (FN 204 s) and very evident at the 35% blend (FN 123 s) level. No discernible differences due to sprout damage were noticed within the composite blends in terms of processing properties, firmness and cooking loss of the cooked pasta, although spaghetti made from the No. 5 sample showed slight checking, higher cooking loss and lower firmness.

Cereal Chem. 85(3):440-444A standardized method to determine cooked spaghetti firmness was developed. The effects of process and instrument variables were investigated and optimized to provide reproducible results between laboratories and to enable discrimination among samples with similar firmness characteristics. Commercial spaghetti samples of varying thickness were chosen to artificially create a range in firmness, and used to investigate the effect of a wide range of variables on cooked spaghetti firmness including sample preparation, cooking procedure, postcooking treatment, sample presentation, and instrument settings. Cooked spaghetti firmness determined using a TA-XT2i texture analyzer was significantly affected by optimum cook time, postcook cooling, rest time, and crosshead speed (P < 0.001), as well as strand length, spaghetti to cooking water ratio, number of strands cut, and strand position (P < 0.05). Although previous work showed a reasonable correlation between laboratories when using in-house methods (r = 0.85), the correlation improved to r = 0.96 when using the standardized method to analyze 29 commercially produced spaghetti samples. The Spearman rank correlation increased from r s = 0.81 to r s = 0.95, prestandardization and poststandardization, indicating greater agreement between laboratories in sample ranking.

Cereal Chem. 88(3):264-270Pasta yellowness depends on the semolina carotenoid content, carotenoid degradation by lipoxygenase (LOX), and pasta processing conditions. In breeding programs, early generation lines are selected for high grain yellow pigment content with the intent to improve pasta color. This approach has been successful in increasing the grain yellow pigment of Canadian durum wheat in the last few decades. In recent years, however, a weak relationship between pasta yellowness (b*) as measured by a Minolta spectrophotometer and semolina yellow pigment content (r = 0.19-0.52) was noted in the Canadian durum wheat lines. Thus, total semolina yellow pigment content cannot effectively predict the yellowness of its pasta product. Therefore, a fast and simple method was developed to predict pasta yellowness by measuring semolina dough sheet color at different time intervals after sheeting (0.5, 2.0, and 24 hr). Spaghettis were processed from the semolina samples at two drying temperature cycles (70 and 90°C). There were significant correlations between dough sheet b* values at all three times and spaghetti b* values at both drying temperatures (r = 0.87-0.94). Semolina dough sheet can be easily prepared in 15 min and requires only 30 g of material. Shortly after sheeting (30 min), dough sheet b* values can be used to predict pasta yellowness without producing the end product (involving mixing, extrusion, and drying). In this study, we also found that dough sheet b* values increased significantly with time over the sampling intervals after sheeting for those breeding lines with superior pasta color. DNA analysis revealed that all those lines lacked the Lpx-B1.1 duplication.

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. 2004. Effect of durum wheat (Triticum turgidum L. var. durum) semolina extraction rate on semolina refinement, strength indicators and pasta properties. Can. J. Plant Sci. 84: 1001-1013. Since the 1980s, there have been general trends in the durum wheat milling industry to higher semolina extraction rate, and in the pasta processing industry to the use of higher drying temperatures. During this time, specification of gluten strength by gluten index, mixograph mixing properties and alveograph parameters has also become widespread. These trends prompted this study of the appropriateness of protocols for quality testing of Canadian durum wheat breeding lines. Four cultivars with intrinsic differences in yellow pigment levels and gluten strength were grown in field plots in Swift Current, Saskatchewan for three consecutive years. A laboratory-scale milling procedure was modified to produce semolina at extraction rates from about 65% to about 80%. Milling to extraction rates above 65%, the extraction rate used routinely in quality testing of Canadian durum wheat breeding lines, had a major impact on semolina ash content and colour, but did not offer any advantage in ranking cultivars for either semolina yield or semolina refinement. Gluten strength, as measured by gluten index, was independent of semolina extraction rate. Dough strength, as measured by mixograph properties and alveograph properties, showed a tendency to weakening at high extraction, particularly for strong cultivars. Semolina was processed into spaghetti using low-temperature (LT), high-temperature (HT) and ultra-high-temperature (UHT) drying cycles. The firmness of cooked spaghetti was predominantly influenced by protein content. As a result, cultivars generally ranked in spaghetti firmness according to protein content. Regardless of drying cycle or cultivar, spaghetti firmness increased as drying temperature increased. Spaghetti dried at LT was less yellow than spaghetti dried at HT or UHT, probably due to thermal inactivation of the bleaching enzyme lipoxygenase at HT and UHT. Regardless of drying cycle, spaghetti became duller, more red and less yellow as extraction rate increased. For each spaghetti trait, cultivar ranking remained relatively constant regardless of extraction rate or drying temperature. On the basis of these results, there appears to be no advantage to increasing semolina extraction rate beyond 65% for evaluation of durum wheat milling performance, gluten strength or pasta properties. In addition, it appears that one drying cycle is adequate to reliably evaluate durum wheat lines for spaghetti colour and firmness. Depuis les années 80, la tendance générale dans l'industrie meunière consiste à extraire de plus en plus de semoule du blé dur alors que l'industrie des pâtes alimentaires recourt à des températures de séchage de plus en plus élevées. Durant le même laps de temps, la détermination de la fermeté du gluten d'après l'indice de gluten, les propriétés de pétrissage révélées au mixographe et les paramètres de l'alvéographe...