Statistical analysis of biscuit physical properties as affected by baking

The variability in the dimensions, weight and moisture content of commercial and laboratory Rich Tea type biscuits has been quantified. An experimental study has been conducted comparing dispersion in dough piece weight and thickness to that of the resulting biscuits. The sensitivity of these biscuit properties to deviations in the baking process and in dough ingredient levels has been investigated. It was found that the dispersion in biscuit weight is primarily due to variability in dough piece weight, which in turn is linked to spatial variations in the thickness of the dough sheet from which the pieces are cut. The baking stage can slightly diminish the distribution in weight by reducing the variability in moisture content between biscuits. The mechanism by which this happens is that wetter dough pieces dry proportionally more than those with lower moisture levels. Biscuit moisture content is sensitive to fluctuations in oven temperature and dough piece moisture content though at a level that may not be commercially significant.