Development and Characterization of Milled Flaxseed Fortified Extruded Bean Snack

N. Vadukapuram¹, C. Hall III^1*, M. C. Tulbek²

Department of Cereal and Food Sciences, North Dakota State University, ²Northern Crops Institute, Fargo, ND.

*Corresponding author: 210 Harris Hall, Dept. Cereal Food Sciences, NDSU, Fargo, ND 58105. clifford.hall@ndsu.edu, 701-231-6359.

Abstract

The importance of omega-3 fortified and gluten free foods is growing daily. Flaxseed is a rich source of omega-3 fatty acids and other healthful components such as fiber and lignan. Beans are known to be highly nutritious due to high content of protein and lysine. Flaxseed fortification in extruded bean snacks will benefit consumers in delivering these healthful components. The impact flaxseed has on the physicochemical properties as well as shelf life and sensory properties of an extruded bean snack were studied. Combination of bean flours were fortified with different levels (0 - 20%) of cold milled flaxseed and extruded in a twin screw extruder. Extrusion was conducted according to standard corn curl processing method developed by Wenger Manufacturing, Inc. Attributes such as water activity, expansion ratio, color and texture were evaluated. Scanning electron microscopy analysis of extruded snack was conducted using magnification X10 and X550. Shelf life stability of extruded bean snacks was evaluated by headspace volatile analysis. Sensory evaluation was conducted using a seven member trained panel. Extruded snack quality analysis indicated that 5 and 10% cold milled flaxseed addition did not affect expansion ratio, bulk density, water activity and snack firmness parameters. Bulk density scores significantly (p < 0.05) increased as the percentage of cold milled flaxseed increased in bean snacks. Extruded snacks fortified with 15 and 20% cold milled flaxseed significantly (p < 0.05) increased water activity values of extrudates. Propanal, the primary aldehyde of α-linolenic acid degradation was observed in samples in aluminum pouches stored at room temperature for four months. Flaxseed addition at 5 and 10% level did not affect sensory scores. Thus, cold milled flaxseed can be incorporated at a 5 to 10% level in bean snacks. Combinations of flaxseed and bean flours resulted in good quality, shelf stable, gluten