INFLUENCE OF FENUGREEK SEEDS FLOUR ON THE RHEOLOGICAL CHARACTERISTICS OF WHEAT FLOUR AND BISCUIT QUALITY

Nowadays, demand for health-oriented products such as functional foods which hashigh fiber products is increasing. So, this work studied the effect of partial replacement of wheat flour(72% extraction) by different levels (5%,10%, 15% and 20%) of raw, soaked and germinatedfenugreek seed flour (Trigonella foenum graecum). The chemical and rheological characteristics forproduced dough blends, and on the sensory, physical and chemical characteristics for producedbiscuits were studied. Results indicated that incorporation of fenugreek seed flour (FSF) obviously (P≥0.05) increased in protein, fat, crude fiber, and ash with increasing FSF supplementing levels. Themineral contents of treated fenugreek seed flours almost was higher than the control samples.Germination process of fenugreek seed flour caused a decrease in the most of minerals compared withthe soaking process. The replacement of wheat flour with fenugreek seed flour caused a decrease (P≥0.05) in extensibility of the dough as measured by the extensograph and an increase (P≥ 0.05) inresistance to extension, proportional number and dough energy tests. Farinograph results showed thatall additions of fenugreek seed flour increased water absorption, dough development time and mixingtolerance index, while decreased dough stability and weakening values in the case of higher replacingwith fenugreek seed flour levels. The effects on dough development time, water absorption, andmixing tolerance indices were intensified with GF (germinated fenugreek seed flour) samples under5% or 10% levels. Generally, the addition of germinated fenugreek flour to wheat flour at ratio of 5 or10 levels had a less deleterious effect on the chemical and rheological properties of dough than that ofRF(raw fenugreek seed flour) and/or SF(soaked fenugreek seed flour). The sensory evaluation resultsof supplemented biscuit showed that a maximum of 10% FSF can be incorporated to made acceptablequality biscuits. While, biscuits containing 15 or 20% FSF were unacceptable to the panelists ascompared with the control biscuit. Results of chemical analyses indicated that incorporation of FSFinto biscuits formula obviously (p≥0.05) increased each of protein, fat, crude fiber, ash andindispensable amino acid (IAAs) contents with increasing FSF supplementing levels. The amino acidscomposition revealed that supplemented biscuits with FSF contained the most of IAAs and will covera highly percentages of reference protein pattern of FAO/WHO (1973). Lysine was the first limitingamino acid in control biscuit samples. Supplemented biscuits with germinated FSF had higher lysinecontents than other treatments. It could be concluded that, incorporation up to a 10% level ofgerminated FSF into wheat biscuit formula resulted in improving their chemical, sensory qualitycharacteristics and complementing the deficiency in lysine amino acid.