The breadmaking quality of Pastiche

Abstract

Pastiche was provisionally recommended by the Cereal Trials Advisory Committee as a hard milling, breadmaking wheat in 1989 and became available in commercial quantities in 1990. By September 1990, the major UK milling companies had rejected Pastiche for breadmaking purposes on the basis of their assessments of commercially-grown samples. An investigation was therefore carried out to discover why a variety which had been provisionally recommended as a breadmaking wheat was found to be unsuitable for that purpose when grown in commercial quantities.

During the first three years of trialling, the performance of Pastiche was assessed against Avalon as the control variety. From the 1989 harvest, Mercia was adopted as the new control for winter breadmaking wheat and was therefore the variety against which Pastiche was judged on commercially-grown wheat.

The results obtained in this project with commercially-grown wheats supported the assessments made on trial assessments using the same testing procedures. Based on the use of potassium bromate as a flour treatment agent, on average Pastiche performed better than Mercia in a three hour Bulk Fermentation Process (BFP) and similar to Mercia in the Chorleywood Bread Process (CBP). Using the CBP with ascorbic acid as the sole flour treatment agent, which was adopted following the withdrawal of clearance for use of potassium bromate as a flour treatment agent in the UK in April 1990, commercially-grown samples of Pastiche were found on average to be poorer than those of Mercia but, in contrast, there was no difference in the average breadmaking performance of Pastiche and Mercia with the 1990 RL samples. Accordingly, the difference in the comparative assessment of Pastiche and Mercia would appear to be due to differences in the properties of commercial and trial samples.

The commercial samples in this study were selected to cover as wide a range of protein contents as possible in order to examine the relationship between loaf volume and flour protein content. Irrespective of the milling and baking procedure used, when individual loaf volumes of the Pastiche samples were plotted against protein content, there was no significant response of loaf volume to increasing protein content and the variation in loaf volume appeared to be greater at higher levels of protein. With Mercia, on the other hand, there is a consistent increase in loaf volume with additional protein content. Since the samples of Avalon, Mercia and Pastiche grown in National and Recommended List trials from 1986 to 1990 were generally of much lower protein content than would be considered by millers to be suitable for inclusion in breadmaking grists, extrapolation of the trial assessments to commercial practice was misleading. This finding would account for the reported difference in the breadmaking performance of Pastiche as assessed on trial and on commercially-grown samples. It is therefore imperative for successful evaluation of breadmaking quality of new wheat varieties that trialling procedures are designed and carried out to reflect, as far as possible, commercial husbandry practice for the production of breadmaking wheat with a minimum protein content of 11% at 14% moisture content and that samples of potential breadmaking varieties which are unsuitable in this respect are not assessed.

Overall, the results of this study confirm the milling industry's reservations about the breadmaking quality of Pastiche and demonstrate that the different assessments obtained between trialling and commercial practice were due to the generally low protein contents of the trial samples which did not enable the lack of response of breadmaking performance to additional protein content in this variety to be identified. These findings are unaffected by the testing procedures used.