2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

Adhesion or stickiness plays a dual functional role in many bakery products. In some instances, stickiness is desirable for appropriate baked product quality (chewy, moist products), but on some other instances, it interferes with the system and may cause major interruption during processing. The objective of this work is to develop fundamental rheological methods to evaluate stickiness of dough. In particular the effect of milling conditions on the stickiness and rheological properties of dough was investigated. Rheological properties of dough were determined using a Dynamic Mechanical Thermal Analyzer (DMTA) and a controlled stress rheometer. Stickiness of dough samples was determined with a Universal Testing Machine (Sintech), which was also used to measure the extensional properties of the dough samples. Two types of wheat were used; hard and soft, milled under different conditions. Samples were equilibrated to several moisture content values and the Tg of the flour was determined by DMTA. The Tg range was reported as the mid-point range of the E' vs. temperature (degrees C) curve. Dough samples were also made from flour produced from the two types of wheat at two moisture content levels and tested in a controlled stress rheometer. Results showed that as the moisture content increases, the Tg of the flour sample decreases regardless the milling conditions. As the number of passes during milling increases, the flour particle size decreases and the Tg values increase. Viscoelastic measurements indicated that the storage modulus (E') also increases as the number of passes increases. Stickiness result showed that as the moisture content and the number of passes increases, the stickiness increases as well.