Submitted to: Journal of Food Processing and Preservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2007
Publication Date: 2/1/2008
Citation: Onwulata, C.I. 2008. Baking Properties of Milk Proteins-Coated Wheat Bran. Journal of Food Processing and Preservation. 32(2008):24-38.
Interpretive Summary: Many consumers in the US are not consuming their daily recommended dietary fiber intake through their diets; most processed foods that they consume are low in fiber, which is essential in maintaining optimum health. Food processors keep the amount of fiber to a minimum because fibers in formulated foods cause texture problems such as soggy and dry patches. Large amounts of dietary fiber in formulated foods absorb moisture from the surrounding ingredients, so its amount is kept to a minimum. To solve this problem, we coated dietary fiber from wheat bran with modified milk proteins, whey and casein; the modified proteins formed a protective barrier around the fibers, preventing them from absorbing moisture from their surroundings. The milk protein coated red wheat bran was used to formulate cookies and muffins, replacing 5, 10, and 15 wt% of the flour. The coated fiber reduced the rate of water absorption by 250 percent and using it in baked cookies and muffins improved volume by up to 60%. Coated dietary fiber can be used in larger quantities in foods to provide many health benefits since they can be added in amounts of up to 15 g per 100 g serving.
Technical Abstract: Increasing the dietary fiber content of formulated foods will benefit the health and nutrition of consumers. The problem has been that it is difficult to add substantial amounts of dietary fiber to formulated foods. Fiber absorbs significant amounts of water from the surrounding ingredients creating texture problems such as soggy and dry patches in the finished products. In this study, red wheat bran milled and sieved below 140 microns was coated by spraying it with a 50/50 emulsion of whey protein isolates (WPI) and casein. The emulsion was produced first by blending and shearing the milk proteins in ice and water, and then evaporating under partial vacuum for 75 min at 45 deg C. Cookies and muffins were made with the milk protein coated red wheat (MPCF) bran and the non-coated wheat bran (NCF) replacing 5, 10, and 15 wt% of the flour and were compared to control cookies and muffins made without added fiber. The water holding capacity of the MPCF and NCF were determined along with their moisture, color, hardness, and volume in the baked cookies and muffins. There was a significant (p< 0.01) improvement (250%) in loss of water holding capacities of MPCF over NCF. In cookies, MPCF absorbed significantly less water and were slightly darker at 5 wt% substitution than NCF, but were between 12 to 60 % higher in baked volume than the control. MPCF muffins were lighter in color and harder except for the 5 wt% sample which was soft and higher in percent baked volume. We’ve concluded that adding up to 15 g MPCF per 100 g product can be added to baked cookies and muffins to increase fiber content and improve water holding capacity and volume.