Effects of ingredients and process conditions on 'Amaretti' cookies characteristics

This research aimed at determining the influence of different factors (i.e. ingredients and process conditions) on the most important characteristics defining consumers' appreciation of 'Amaretti' cookies using DOE (design of experiment) technique. A different recipe than the original one was used in the manufacturing of the cookies, where saccharose was partially replaced with fructose and bamboo fibre was added as a new ingredient. Besides fructose/saccharose ratio and fibre, the effect of egg white, baking time and baking temperature on quality responses (hardness, water activity, moisture content and colour) of 'Amaretti' was measured by using a fractional factorial design in a screening test. Responses were affected mostly by changes in temperature and fructose/saccharose ratio levels and then by baking time; bamboo fibre had a statistically significant influence only on hardness. The power of fit of the regression models was significant for all four responses and had R ² value in the range of 0.886–0.997. However, the power of prediction was significant only for hardness, moisture content and colour and had Q ² value in the range of 0.584–0.965. The mathematical model for water activity resulted inappropriate to explain the link between factors and response. The achieved results can represent a useful tool to address and facilitate the next phase of optimisation.