The impact of extrusion processing on fortified breakfast cereals containing β‐glucan‐enriched flour: physical, structural, and nutritional aspects

Abstract

BACKGROUND: This study evaluated the effects of various factors on breakfast cereals containing ⊎-glucan-enriched flour frac-tion (BEFF). A central composite design (CCD) was used to examine the effects of BEFF level, screw speed, and die temperatureon the physical, textural, microstructural, and nutritional properties of the cereals. RESULTS: The addition of BEFF initially increased the L* value by 5.1%, followed by a decrease at higher levels. Porosityincreased linearly, whereas starch digestibility decreased. Screw speed was the most significant independent variable affectingthe physical and structural properties of the cereals, followed by die temperature. The optimum processing conditions were5.1% BEFF, 435 rpm screw speed, and 170 °C die temperature (with the other barrel zones maintained at 40, 50, 70, 90, and100 °C), yielding ⊎-glucan content of 14.3 g kg−1 and starch digestibility of 196.46 mg maltose g−1 . ⊎-Glucan loss was limitedto 42% at most when compared with the unextruded blend. CONCLUSION: Extrusion increased starch digestibility and reduced ⊎-glucan content, and the enthalpy of starch gelatinizationtended to decrease with BEFF incorporation into the control sample. All breakfast cereal products in this study met Food andDrug Administration (FDA) requirements, containing at least 0.75 g of ⊎-glucan per serving portion.