Effect of jet milled whole wheat flour in biscuits properties

• Micronization of whole wheat flour (WWF) by a jet mill.
• Successful substitution of biscuit flour at different ratios.
• Best products at 50% substitution levels.
• Higher substitution level: cohesive batter, hard, dark biscuits.

There is a great interest of improving the quality of whole wheat products. In our study whole wheat flour (WWF) was micronized substituting biscuit flour (BF) at different levels. Four micronized flours (JMWWF), of particle sizes ranged from d50:53.49 μm to d50:17.02 μm, were produced in different milling conditions. The water holding capacity (WHC) of the fine whole flour increased up to 9%. However, the viscosity of the produced batter was up to 8 fold greater than that of the control, negatively correlated with the particle size of JMWWF. Consequently, the produced biscuits became very hard as flour particle size decreased and substitution level increased, suggesting that the intense milling resulted in detachment of wheat compounds and enhancement of the interactions among different ingredients in baking process. Biscuits' snap force was further positively correlated with moisture, but negatively to spread factor (SF) and lightness. Biscuits prepared with WWF showed the strongest decrease (23%) in SF when substitution level increased from 18.5 to 100%. A reduced SF and a high density was noticed in all samples at 80% and 100% substitution level. Biscuits with 50% JMWWF had good sensory attributes. Higher substitution levels are not recommended.