Wheat gluten is the most important by-product of the starch industry and it is composed of two major fractions, gliadins and glutenins. After drying and pulverization, the powder also known as vital gluten is used in a wide variety of foods. When water is added again, vital gluten regains its cohesive, elastic and viscous properties that ensure high water-binding capacity and gluten network formation. One of the main fields of application for vital gluten is the baking industry where it strengthens the gluten network, delays staling and improves product quality. To prevent nitrate from leaching into the ground water, nitrogen and phosphate fertilization during wheat production are increasingly being restricted and this is known to cause lower protein content in wheat. The use of vital gluten is thus a possibility to compensate for the decreasing protein content and maintain product quality. However, vital gluten functionality shows large variability even if comparable specifications are met and even from the same manufacturer, but between different batches. The baking test is typically used to assess functionality, but easier and faster tests are required for wheat breeders, handlers, millers and bakers.<br/>The aim of our study was investigate the suitability of new tests to predict the functionality of vital gluten in bread making. The new tests were the determination of gliadin/glutenin ratios, the microscale extension test and the gluten aggregation test.<br/>Two high-protein bread recipes were used to evaluate the bread making performance of 46 vital gluten samples. Hierarchical cluster analysis of the specific bread volumes efficiently separated the samples into good, medium and poor baking quality. Correlation analyses were carried out between all parameters of the tests and bread volume. Significant correlations were subsequently used to develop a scoring system. The gliadin/glutenin ratio only showed a weak correlation (r = 0.3, p &lt; 0.05) with the specific volume and was not sufficiently accurate to predict gluten functionality. In contrast, the microscale extension test assigned 52% of vital gluten samples to the correct quality class and the gluten aggregation test even 63%. Both tests were, therefore, suitable to predict vital gluten functionality. Compared to the baking test, both new alternative tests require less time and labor and will help determine which batch of vital gluten is best suited for specific applications in the food industry.

New tests to predict the functionality of wheat gluten in bread making

ACS Fall 2021

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