THE INFLUENCE OF GRAPE POWDERS ON THE RHEOLOGICAL PROPERTIES OF DOUGH AND CHARACTERISTICS OF THE QUALITY OF BUTTER BISCUITS

Abstract

The effect of grape powders on the rheological properties of dough and the indicators of butter biscuits quality have been investigated. Butter biscuits were cooked with the addition of powdered grape seeds and grape skins from the grape pomace obtained in the southern regions of Ukraine. The grape powders were added to the dough in an amount of 15.0% of the weight of the wheat flour. It has been shown that the presence of powdered grape skins increases the dough’s effective viscosity by 3.9 times, of powdered grape seeds – by 5.4 times, as compared to the reference sample, and it makes the dough more resistant to destruction. Adding powdered grape skins increases the plastic viscosity of the samples by 31.4%, powdered grape seeds – by 38.1%. The higher plastic properties of the dough allow the biscuits to hold their shape better and to retain the pattern on their surface. With grape powders added, the adhesive strength of the dough decreases. When powdered grape skins are added, the adhesion strength decreases by 23.0 %, and if we add powdered grape seeds, by 33.0%. It facilitates the work of moulding equipment and reduces the production losses of the dough during processing and moulding. The values of physicochemical parameters of the quality of butter biscuits – the specific volume and the wetting ability – slightly increase as compared to the reference sample. Products hold their shape better, and do not become runny during baking, because of a higher degree of form stability. Organoleptic indicators of the quality of butter biscuits with experimental additives are becoming better. Biscuits acquire a pleasant nutty taste after adding powdered grape seeds, and the taste and flavour of prunes and raisins after adding powdered grape skins. Butter biscuits take a deep chocolate colour or chocolate with a violet tint.