High-fiber extruded cereal product incorporates apple.

We all know that incorporating fiber into our diets offers many positive health benefits. Fiber promotes the wavelike contractions that keep food moving through the intestine. Also, high-fiber foods expand the inside walls of the colon. This eases the passage of waste. Fiber is not digested by the human body. For this reason, it can help correct disorders of the colon and keep it functioning normally.

Mexican researchers wanted to develop and evaluate a high-fiber product of acceptable quality, manufactured by extruding a mixture of apples, oats and wheat bran. In this product, all three components supplied fiber. Apples supplied flavor. Oats were the cereal base. The significance of this research is that it was possible to make an acceptable high-fiber extruded cereal product by incorporating apple. Adding this component led to a product with good appearance, flavor and color.

Scientists developed an experimental design using two moisture levels--24% and 28%--and four levels of apple content--0%, 2.5%, 7.5% and 12.5%. The product's base mixture contained 70% oats and 30% wheat bran. Investigators kept a variety of extrusion parameters constant: die design, screw speed (140 rpm) and barrel temperature distribution (70 C, 90 C and 100 C).

After extrusion, the product was dried to a 4% moisture content. Quality parameters evaluated in the final product included color (L, a, b); water solubility; absorption and expansion indices; apparent density; shearing stress; TBA value; crude fiber; and mouthfeel. The L and b parameters significantly decreased and increased, respectively, by increasing the amount of apple in the product. The "a" parameter and apparent density were unaffected.

The water absorption and solubility indices, as well as shearing stress, were significantly affected by moisture and apple content. Crunchiness increased based on apple content. Samples containing the maximum amount of apple (7.5% and 12.5%) exhibited lower TBA values. Fiber content increased with increasing apple content. Sensory testing was unaffected by apple content. The extruded product was found to be "moderately liked" by testers.

Further information. Victor Santana-Rodriguez, Faculty of Chemical Sciences, Universidad Autonoma de Chihuahua, Av. Escorza y Venustiano Carranza S/N., CP 31000, Chihuahua, Chih., Mexico; phone: [phone]; fax: [phone]; URL: www.uach.mx.