Characterization of Cohesive Cake Formation and Stickiness of Starches at Various Water Levels in the Presence of Palm oil and Palm Oil Fractions

A key feature of the biscuit manufacture is the combination of the raw ingredients. Different oils are likely to change the quality of dough. The factors important in agglomeration of starch materials are poorly understood and therefore work was carried out to try and establish the behaviour of oil and water on the material properties of starches. An understanding of particle-particle behaviour in the presence of oils and water is relevant to a food production process such as biscuit making, that requires preparation and mixing of these ingredients at ambient conditions. The way these powders pack and flow could have a significant impact on the final quality of the product. Powder flow analyser was used to measure the caking and cohesion properties for different type of starches. Besides the powder type as a variable, three levels of water and four types of oils at 5 % (d.b) concentration were also tested. The presence of water with the powder plays an important role for the way the cereals powders pack and flow. Although tapped bulk densities did not vary much the water had a great impact on the powder caking strength and cohesion index. For samples without oil, the results showed that these parameters were increased significantly as the water level increased for all starches. Plasticization by addition of water to the food powder is believed to be the major factor contributing to the results obtained. Addition of oil to starches increased the caking and cohesion indices where liquid oils showed the greatest impact compared to solid oils.