No abstract

Cereal Chem. 82(5):601-608The effects of varying the gluten composition at constant protein, protein content at constant composition, and glutenin-to-gliadin (glu/gli) ratio on durum semolina rheological properties and the quality of the spaghetti derived from these doughs was investigated using the reconstitution method. Reconstituted flours were built up from a common durum starch and water-soluble fraction but with varying gluten types from a range of wheats at both 12 and 9% total protein. A 10-g mixograph and microextensigraph properties were affected by the source of the gluten, which was related to glutenin composition and polymeric molecular weight distribution. Cooked pasta firmness was highly correlated to mixograph development time (MDDT). Furthermore, varying the protein content (9-20%) showed an increase in mixograph peak resistance (PR) with no effect on extensigraph Rmax. Pasta firmness increased and stickiness decreased with increasing protein content. In another experiment, the glutenin and gliadin fractions isolated from durum wheat were added to the respective base semolina to investigate the effect of varying the glu/gli ratio by 1.3-1.6 fold. Increasing the ratio increased MDDT but had no effect on PR and resistance breakdown. Variable effects were obtained for spaghetti firmness. The information obtained should prove useful to durum breeders by providing further evidence for the importance of protein to pasta quality.

Cereal Chem. 89(2):84-93-Glucan is known to have valuable properties for preventative health and is finding widespread use in foods. This study investigated the benefit of adding a commercial source of -glucan, Barley Balance (BB) flour, as a functional ingredient in spaghetti. Durum wheat semolina was substituted with BB at levels of 7.5, 15, and 20%, from which spaghetti was prepared on a laboratory scale. The substitution of BB increased the -glucan content of semolina from 0.3 to 6% in uncooked and 8% in cooked pasta. Antioxidant activity (measured by 2,2-diphenyl-1-picrylhydrazyl) increased with BB and did not decline significantly on process-ing and cooking. Compared with the control, 7.5% BB had no or minimal effect on pasta cooking loss, stickiness, water absorption, aroma, and sensory texture. However, at higher doses, pasta became less yellow and more brown, firmer, of inferior aroma, more rubbery, and chewy, but less floury to the mouth. The extent of starch digestion decreased with increasing quantities of BB, suggesting that BB may lower glycemic index, with microscopy data suggesting that this decrease was mediated through the development of a more intensive fiber or fiber/protein matrix retarding enzymatic access to starch granules.* The e-Xtra logo stands for "electronic extra" and indicates that Figures 1, 3, 4, and 5 appear in color online.

Selected Indian durum wheats including five newly released varieties and seven landraces were studied for their grain quality, gluten strength (sodium dodecyl sulphate-sedimentation and mixograph) and pasta making properties. Landraces were found to have good grain size, protein content, and gluten strength but they had lower test weight and semolina yield than released varieties. As protein composition affects gluten strength, landraces having combination of low molecular weight (LMW-GS) with 5, 12, 15 and 19 linked to Gli-B1 43.5 and high molecular weight (HMW-GS) 2*, 14 + 15 provide a dough strength comparable with the 7 + 8 and LMW-GS 2, 4, 6, 12, 15 and 19 (caa) allelic pattern, typically associated with good gluten strength. Landraces have rare combinations of glutenins and gliadins, which are not seen in commercial Indian durums, and in some cases, these rare alleles seem to favour good gluten strength and pasta firmness. Introduction of these alleles through breeding should improve the gluten strength and pasta making properties of Indian durum cultivars.

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.