Staling of cereal bran enriched cakes and the effect of an endoxylanase enzyme on the physicochemical and sensorial characteristics.

The staling of cakes enriched with untreated brans and endoxylanase-treated brans was evaluated by monitoring the changes in physicochemical, thermal, and sensorial properties of cakes during 7-d storage. Oat and rice bran were treated with different levels (0, 70, and 700 ppm) of an endoxylanase enzyme and added to cakes on 30% flour weight basis. Moisture losses, water activity, crumb firmness, starch retrogradation, and sensorial characteristics were used as staling indicators. Avrami-type equations were efficiently used for modeling the starch retrogradation kinetics, while linear models most adequately described crumb firming kinetics. Cake staling induced an increase in crumb firmness and enthalpy of amylopectin retrogradation, and a decrease in crumb moisture and sensory quality and acceptability scores of cakes. Oat bran-containing cakes better maintained their characteristics compared to the ones containing rice bran along the 7-d storage. Endoxylanase treatment of brans delayed the changes naturally induced during staling in crumb moisture content, amylopectin retrogradation enthalpy, and crumb firmness in the respective cakes. Deterioration of the sensorial characteristics was slower for the cakes containing endoxylanase-treated brans, as well. The level of endoxylanase treatment did not differentiate significantly (P < 0.05) any of the staling indicators. Overall, this study demonstrated that addition of endoxylanase-treated brans can result in cakes with improved nutritional characteristics and increased shelf life.

CONCLUSIONS

The results of the study show the potential of using enzymes to modify underutilized food sources that can be properly incorporated in baked goods, improving their nutritional value, their quality characteristics, and providing longer shelf life. The developed procedure and results can be utilized by the bakery industry to make high fiber and low cost bakery products with improved sensorial characteristics that are appealing to the consumers.