Germinated Wheat Starch as a Substrate to Produce Cyclodextrins: Application in Inclusion Complex to Improve the Thermal Stability of Orange Essential Oil

Wheat pre-harvest sprouting (PHS) is caused by high rainfall especially when the grain is in the filling stage. PHS decreases the grain yield, and is harmful to flour technological quality for baking, with a consequent decrease in economic value. However, the amylolytic activity promoted by germination can facilitate the production of cyclodextrin (CDs). The influence of germinated wheat starch concentration (1% and 10%) on the production of alpha, beta, and gamma-CD is verified. In addition, the thermal stability of the inclusion complex between CDs produced from germinated wheat starch and orange essential oil (CDs/OEO) is also evaluated. The germination promotes the highest conversion yield (54.4%) at the lowest starch concentration (1%) used. The CDs/OEO increase the orange essential oil thermal stability, promoting their protection at high temperatures. Therefore, this study shows that germinated wheat starch is a promising substrate for the cyclodextrin production, adding value to this product that is, normally, not used by the food industry, but for animal nutrition or discarded.