Do classical wheat quality assessments deliver relevant results for modern wheat cultuvars?

Abstract

For cereal food production, quality assessment of wheat is targeted at specific processing demands among which those for yeast leavened goods, especially bread, play a crucial role. In this regard, a baking test would deliver the most comprehensive information. A baking test, e.g. according to ICC Standard No. 131, however, is time consuming and affords a respective technical equipment which is mostly not available on most of the levels of the cereal production and processing chain (breeders, traders, etc.). Further, in labour-intensive time periods, like harvest and collection of the bulk goods, there is no time for a long duration baking procedure. Therefore, it is a world-wide common practice to make use of indirect quality criteria for predicting the tentative processing, especially baking performance, of an individual wheat lot. Adapted to the specific quality expectations of baked goods in different parts and/or countries of the world, respective favoured analytical quality-related methodologies may vary. But due to the significant role gluten plays in wheat baking, all quality assessment systems have protein/gluten related methods in common, such as ICC Standards No. 105/2 (crude protein content), 106/2 (wet gluten content) or 116/1 (Zeleny sedimentation value), respectively. With examples from the German wheat market, it can be outlined that prediction of the baking behaviour of a specific wheat cultivar, of bulk wheat raw material or flour prepared thereof, respectively, has been well established and accepted as being sufficiently precise for decades, based on traditional quality parameters resulting from respective internationally standardized methods. Thus, knowing the cultivar was sufficient so far to analyse the total protein content plus the sedimentation value of a sample to calculate the baking volume to be expected of the baked good. This theoretical result calculated by means of a specific equation has been well in accordance with the real volume as result of a standardized baking test (RMT = Rapid Mix Test). This established system worked well with “traditional” wheat cultivars having “classical” gluten functionality. In very modern wheat varieties, however, a distinct discrepancy between theoretical volume prediction and the real baking result becomes obvious as these varieties are characterized by lower total protein (and gluten) content but much improved gluten functionality, i.e. volume forming capacity. The meaning of these findings for wheat breeding, trading (payment!) as well as processing, are important. In consequence, the question has to be answered if novel (rapid) quality assessment methods will be needed or if existing standard methods will have to be improved or adapted.