Higher Loaf Volume Research Articles

Relationship between High Molecular Weight Glutenin Subunits and Loaf Volume in Wheat as Measured by the Sodium Dodecyl Sulphate Sedimentation Test1

The objective of this investigation was to evaluate the contribution of different high molecular weight (HMW) glutenin protein subunits in wheat (Triticum aestivum L.) to loaf volume as measured by the sodium dodecyl sulphate sedimentation test. Two segregating populations were developed from parental lines differing in their HMW glutenin subunits. ‘Buck Pucara,’ a hard red spring cultivar developed by Criadero Buck in Argentina, was crossed to two spring wheat hexapioids, lines 13 and 14, developed at the Volcani Institute in Israel and derived from wild emmet (Triticum turgidum L. var. Dicoccoides Korn Bowden). Parents, F2 individual plants, and F2‐derived F4 segregating lines were evaluated. Combined effects of the good quality glutenin subunits from each of the alleles tested were not additive as previously reported. Bands 5 and 10 in a homozygous state always were associated with higher loaf volumes than bands 3 and 12 or the heterozygous state bands 5 and 10 + 3 and 12, contributed by the D genome. The importance of individual subunits in the A and B genome depended on the interaction with other glutenin proteins. There was evidence for intra‐allelic interactions among HMW glutenin subunits in a heterozygous state. Hybrid wheat breeders may find it difficult to predict loaf volume based on the banding pattern of the corresponding parental combinations.

Soy flour in European‐type bread

Effect of soy flour, soy protein concentrate, and isolate on dough and loaf properties of breads produced from flour, yeast, salt, and water with no shortening or added improvers was investigated. Wheat flour, rye flour, and mixtures of the two were included in the studies. Three wheat flours, varying in baking quality and extraction, ash content 0.65 and 0.80%, were used; 1.5, 3, and 5% soy products, flour basis, were added. Water absorption increased 3.8–4.7% at the 3% soy level and 6.1–7.3% at the 5% level of soy product addition. Dough development time and stability were increased and dough softening reduced. Dough gassing power increased ca. 7–25%. By using a shorter proofing time, more intensive mixing, and the sponge dough process, loaves only slightly smaller in volume than the control were obtained at the 3% soy level. Panel evaluations scored bread highest with 1.5 or 3% soy flour and that with 3 or 5% soy protein concentrate as lowest, but acceptable. Use of 2% lard as shortening, or 2% lard plus emulsifier, produced soy breads of excellent quality and ca. 25% higher loaf volume than controls.

Influence of a gene causing hardness on the milling and baking quality of two wheats

Near-isogenic lines of Falcon, a hard wheat with good baking quality and high milling extraction, and Heron, a soft wheat of medium baking quality and rather low milling extraction, were produced differing only in the gene which determines hardness as measured by the particle size index. It is shown that the superiority of Falcon in milling extraction, loaf texture, and dough handling characteristics is very strongly associated with the gene which causes it to be a hard wheat. While Falcon generally has a loaf volume superior to that of Heron, if the genetic background of two wheats is identical except for hardness, soft wheats have higher loaf volumes. Because these three variables, which largely constitute total loaf score, are not all favoured by the same particle size index, total loaf score is less clearly influenced by hardness. Nevertheless hard wheats are always superior to, or not significantly different from, soft wheats of the same pedigree in this respect. This work points out the difficulty of producing really good quality soft wheats but on the other hand shows that soft wheats can easily be improved in at least some features of baking quality by the simple process of making them hard.