Available online at http://journal-of-agroalimentary.ro Journal of Agroalimentary Processes and Technologies 2010, 16 (3), 333-340 Journal of Agroalimentary Processes and Technologies ____________________________________________ Corresponding author: e-mail: maria.iancu@ulbsibiu.ro The influence of potato varieties grown in Fagaras area on rheological characteristics of dough for bread with potatoes Maria Lidia Iancu 1* , Luiza Mike 2 , Vasile Jascanu 3 1 Lucian Blaga”University of Sibiu,Faculty of Agricultural Science ,Food Industry and Environmental Protection , Food Biotechnology Department,5-7, Dr.Ion Ratiu st.,Sibiu,Romania 2 Potato Research and Development Station Targu Secuiesc 55, Ady Endre str.,Targu Secuiesc, Romania 3 Alma Mater “University of Sibiu, 57, Somesului st., Sibiu, Romania Received: 30 May 2010; Accepted: 17 August 2010 ______________________________________________________________________________________ Abstract The objective of this study is to examine the behaviour of white flour with additives dough (WF add) and brown flour with additives (BF add.) which was replaced hydrothermally treated and chopped potato, Laura, Impala, Lady Claire, Lady Christl and Orchestra varieties, at a rate of 5%, 10 %, 20 %,30 %. For the rheological characterization of the mixtures we used Flourgrapf E6 Haubelt. We obtained mixtures with different rheological properties. We compared the parameters characterizing the flourgrams for each potato variety used for each type of flour. The formation time and stability decreased, the degree of softening increased and the quality number was increasingly smaller. The hydration capacity of the mixture lowered on average with 27,9% for the mixture of white flour with additives and 31,2% for the mixture of brown flour with additives. From the results obtained it was concluded that the potato variety that less destabilizes the structure of the mixture is Laura variety if flour is replaced with potato in small proportions, 5% -10% and Lady Christl or Lady Claire, if flour is replaced with potato in large proportions 20% -30%. The quality of the obtained dough is different, although the amount of water was added up to a consistency of 500 HE (Haubelt units). We observed that differences arise due to a change in the composition of the mixture under analysis which implicitly leads to changes in friction, the ratio between hydrophilic and hydrophobic groups and redox reactions. Keywords: rheology , Flourgraph E6 Haubelt, water absorbtion, quality number, flour, potatoes ______________________________________________________________________________________ 1. Introduction Dough rheology play an important role in the quality of baking products [3] and morevor posed many intriguing questions about mechanical behavior. The investigation of dough rheology goes back a long way; the early work (1932-1937) of Schofield and Scott Blair [16] estabilished the solid like behavior of dough, and science then there have been many investigations [3,11]. In 1930 the first special instruments to study dough were created, among which the farinograph and mixograph, that give the force moment generated during dough mixing [11]. The characteristics of dough with hydrocoloids adding was studied using the Brabender farinograph [15]. To determine the rheological characteristics of dough we can also use the E 6 Flourgraph, and dough consistency and softening degree is expressed in HE (Haubelt units). The correlation between the farinographic units and Haubelt units were made for white flour with additives and brown flour with additives. The correlation indices, R 2WFadd = 0,8441; R 2BFadd. = 0,9995 [9] demonstrates that the two devices can similarly characterize the colloidal mixture.