Due to climate change sorghum might gain widespread in the Western countries, as the grain is adapted to hot climate. Additionally sorghum contains a notable amount of health-promoting nutrients. However, Western countries do not have a long history of sorghum consumption, and thus little experience in processing it. Milling systems in these areas were mostly developed for wheat or rye milling. In the present work, the effectiveness of sorghum milling when using a stone and a roller milling system (pilot scale) was investigated as well as its impact on the chemical and physical properties of the obtained flour fractions and whole-grain flours. Results showed that both milling systems could be successfully adapted to producing chemically and physically distinct flour and bran fractions from the small sorghum kernels. Fractions with increased bran material that contained higher amounts of ash, protein, fat, total dietary fiber, and total phenolic content but less starch, showed enhanced water absorption indices and water solubility indices. Interestingly, no significant difference was found in the ash and fat content of the different fractions obtained from stone milling. Overall, the study provided information on the production and composition of distinct flour fractions, which offer a wider range of future food applications.

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Background and objectives Lipases are applied in breadmaking as an enzymatic replacement for typical bakery surfactants like Diacetyl tartaric ester of monoglycerides (DATEM) (diacetyl tartaric ester of monoglycerides). In this study, the influence of six commercially available lipases and DATEM on bread staling and bread height was investigated. Therefore, a microbaking experiment was conducted, where 15 g of dough was used for each bread. Microbaking breads were analyzed for height, baking loss, and crumb firmness. Evolution of crumb firmness was measured seven times during a storage period of up to 10 days, under a controlled atmosphere (20°C). Findings All additives increased bread height significantly in comparison with the control (without DATEM and lipase). Maximum height was achieved by addition of DATEM. All additives had a significant antistaling effect in comparison with the control. The lowest bread firmness throughout the whole storage period was achieved by addition of DATEM. Between the six lipases significant differences existed, suggesting a diverse influence of their lipid products on bread staling and bread height. Conclusions Taken together, none of the lipases was able to replace DATEM without the occurrence of reduced bread height and worsened staling behavior at the applied concentrations. Significance and novelty Although lipase addition in general had a positive effect on increasing bread height and retarding staling, it has to be considered in future work that none of the studied lipases was able to replace DATEM and great differences between the single lipases existed.

SummaryIn general, micro-baking tests are used to determine the baking quality when only low amounts of test flour are available, for example, in grain breeding. Several micro-methods are described in literature, but none of them allows the determination of bread crumb texture parameters. Therefore, a micro-baking procedure that offers this option was developed, and it was also evaluated for bread made from pre-fermented frozen doughs. In this procedure, Rapid Visco Analyser (RVA) sample cans were used as baking pans. To examine the capability of this procedure, three wheat flours with different starch properties were chosen. The obtained breads were analyzed with respect to specific loaf volume, crust color and bread crumb firmness. Additionally, a storage test (0-5 days) was performed to determine the crumb firming parameters by kinetics of the Avrami equation. The obtained specific bread volumes revealed significant differences between the flours and the coefficients of variation ranged between 4.2 and 5.5%. Crumb firmness measurement was able to identify significant differences within the samples. The obtained data on firming kinetics reflected the expected properties of samples with different starch properties. Overall, this work demonstrated the feasibility of crumb property measurement on breads on a micro-scale.Keywords: bread staling, wheat quality, Avrami, bread crumb properties, Rapid Visco Analyser ZusammenfassungMikrobackversuche werden zur Bestimmung der Backqualität bei Vorliegen von nur geringen Mehlmengen angewendet. In der Literatur sind dazu bereits mehrere Methoden beschrieben, jedoch bietet keine die Möglichkeit, Texturparameter der Brotkrume zu erfassen. Darum wurde in dieser Arbeit eine Methode entwickelt, die dies ermöglicht. Es wurde auch eine Methode für Brot aus vorgegarten Tiefkühlteiglingen definiert. Als Backformen kamen Probenbehälter des Rapid Visco Analysers (RVA) zum Einsatz. Um die Differenzierungsfähigkeit dieser Prozedur zu bestimmen, wurden drei Weizenmehle mit verschiedenen Stärkeeigenschaften dem Test unterzogen. Von allen Broten wurde das spezifische Volumen, die Krustenfarbe und die Krumenfestigkeit bestimmt. Außerdem wurde ein Lagertest (0-5 Tage) durchgeführt, um basierend auf der Avrami-Gleichung die kinetischen Parameter des Altbackenwerdens zu ermitteln. Die spezifischen Volumina der einzelnen Brote unterschieden sich signifikant voneinander, wobei die Variationskoeffizienten der einzelnen Versuche zwischen 4.2 und 5.5 % lagen. Auch bei der Messung der Krumenfestigkeit konnten signifikante Unterschiede zwischen den einzelnen Mehlen identifiziert werden. Die kinetischen Kennzahlen zur Beschreibung des Altbackenwerdens spiegelten wie erwartet die unterschiedlichen Stärkeeigenschaften der einzelnen Proben wieder. In der vorliegenden Arbeit konnte erfolgreich die Durchführbarkeit der Bestimmung von Krumeneigenschaften im Mikrobackversuch demonstriert werden.

Wheat flour pasting properties change during flour storage. Only little is known about the contribution of α‐amylase on this effect. This study aimed to monitor the changes in rapid visco analyser (RVA) pasting viscosities of four different wheat flours during 360 days of storage. To get an isolated view on the influence of α‐amylase, RVA curves were determined either with water or with 2 mM silver nitrate to inhibit α‐amylase. After 360 days of storage RVA final viscosity of the flours increased between 31 and 56%. When α‐amylase was inhibited it increased only by 12–28%. Remarkably, trough viscosity did not change during a storage time of 180 days when α‐amylase was inhibited. To estimate the α‐amylase activity of flours the ratio between peak viscosities of flour with and without inhibition was calculated. The estimation resulted in a decrease of α‐amylase activity by 22–43% during 360 days of storage. These findings suggest that the decrease of α‐amylase activity is a major influencing factor in the increase of pasting viscosity during flour storage. Additionally, differential curves from analyses with and without α‐amylase inhibition are a helpful tool to improve the understanding of the enzymes mode of action.