Saara Sammalisto's doctoral thesis improves the understanding of oat baking

In her doctoral thesis, Saara Sammalisto (Doctor of Food Sciences) investigated factors affecting the quality of oat baking.

In her doctoral thesis, Saara Sammalisto (Doctor of Food Sciences) investigated factors affecting the quality of oat baking. Doctoral thesis included studying hydrothermal steaming and tempering treatment of oats (which is included in the milling process of oats), examining baking properties of twenty oat cultivar samples, and investigating functionality of various hydrocolloids in oat baking. All baking studies were conducted as 100% oat baking, without wheat or gluten additions.

Both native oat groat properties and hydrothermal treatment parameters were shown to affect oat flour particle size. At higher treatment temperatures, softer oat groats were obtained, which were milled into finer oat flours. Oat cultivar samples varied regarding processability as in softer native groats, also moisture content during hydrothermal treatment affected oat flour particle size. Thus, by choosing soft groats and by altering the hydrothermal treatment parameters, oat flour particle size can be optimized for specific uses, such as for baking applications.

Twenty whole grain oat cultivar samples showed notable variation in their baking properties, such as in optimized dough yield, dough consistency, specific volume, and bread crumb properties. Best baking properties were obtained with the oat cultivar samples which had the highest optimal dough yields. According to the statistical analysis, higher fat content and smaller particle size of the whole grain oat flours were related to good baking properties of oats, such as high specific volume and soft crumb structure of the bread. Presumably, higher fat content of the oat flours improved gas cell stabilization in oat dough, which led to increased volume of oat bread. Smaller particle size was related to softer bread crumb structure and reduced staling rate, probably by improved hydration of oat flour components and more evenly distributed water in the dough. Instead, protein, starch, ash, dietary fiber, and β-glucan contents of the oat flours did not notably influence baking properties of whole grain oat cultivar samples.

Regarding hydrocolloids studied in oat baking, it was observed that commercial hydrocolloids could be replaced in oat dough with oat β-glucan extract. With oat β-glucan extract as a hydrocolloid, similar specific volume and softer bread crumb structure were obtained in oat bread compared with use of common commercial hydrocolloids (psyllium and HPMC) at optimized addition level. Apparently, β-glucan in oat β-glucan extract could bind water better and stabilized the viscosity of aqueous phase of oat dough. Removal of the insoluble fraction from oat bran concentrate was necessary for the improvement in crumb properties, as it presumably caused disruptions in oat dough structure and interfered water distribution in the dough. In oat doughs containing all fractions of OBC or psyllium and HPMC, competition for water was presumably increased, which decreased dough stability and bread quality.

The results of this study provide better understanding about factors affecting the baking properties of oats. The findings can be utilized in design of new oat bakery products and they provide a starting point for future oat baking research.

Link to the doctoral thesis: