بررسي رابطه فراسنجه هاي ارزيابي كيفيت فرآيند تبديل برنج اصفهان و خواص فيزيكي و مكانيكي آن

چكيده انگليسي :

Abstract In spite of good aroma and flavor of cooked rice for common rice varieties in Isfahan province they have excessive breakage losses qualitatively So the knowledge of effective parameters on these losses is vitally important In this research the main quality assessment parameters of rice milling including head rice yield HRY and degree of milling DOM were determined from milling experiments The experiment were conducted for common rice varieties in Isfahan as Sazandegi Nogaran and Sorkheh at different moisture contents MC of 7 9 9 11 11 13 and 13 15 w b by two laboratory rice miller types abrasive and frictional As the inherent properties of kernel could affect HRY and DOM values some physical and mechanical properties were determined as well The physical properties included size and shape for rough rice and coefficient of external friction for brown rice The mechanical properties were rupture force rupture energy specific rupture energy and maximum bending stress The experiments were carried out with factorial layout in completely randomized design The independent variables were variety type rice miller type and MC To determine HRY and DOM first the selected rough rice sample for each treatment was dried in a fixed bed dryer at three replications and then was husked and whitened by a roll rubber sheller and two rice miler types respectively HRY was computed through USDA standard procedures and DOM was determined by two methods 1 a milling meter DOMMM and 2 the amount of bran removed from the brown rice DOMM Two compound index were defined by multiplication of HRY and two degree of milling C IM and C IMM respectively by HRY and DOMM and HRY and DOMMM Three main dimensions equivalent diameter and sphericity were measured at 100 replications for each treatment and external coefficient of friction of brown rice was measured on four different surfaces at 3 replications Mechanical properties experiments were conducted by three point bending test performed by a universal tension compression test device model instran 1140 at 10 replications for each treatment The desired characteristics were determined and computed from force displacement curve The results indicated that the rice miller type had a significant effect on HRY DOMM DOMMM C IM and C IMM According to the investigated parameters the abrasive type had a better performance than frictional type The effect of variety type on HRY and DOM and all physical and mechanical properties was significant HRY decreased by increasing MC but DOM showed no obvious trend Except for major diameter the MC affected all other physical properties significantly so the intermediate and minor diameters sphericity and equivalent diameter increased and external coefficient of friction decreased as the MC increased All above mentioned mechanical properties reduced by increasing MC Considering HRY and mechanical strength Sorkheh variety had a higher performance in comparison with two other varieties Consequently its DOM was significantly lower than Sazandegi and Nogaran varieties This could be because of the size and shape of the varieties and verifies that Sazandegi is modified variety of Nogaran The correlation of HRY to three main dimensions showed that this parameter varied reversing by intermediate changes of the varieties but based on the bending stress formula this relation is not logical and has been obtained through physical properties and natural strength of Sorkheh variety In comparison varieties relation between HRY and fracture force maximum bending stress fracture energy and In comparison moisture contents relation between HRY and fracture force and maximum bending stress were significant pdfMachine Is a pdf writer that produces quality PDF files with ease Produce quality PDF files in seconds and preserve the integrity of your original documents Compatible across nearly all Windows platforms if you can print from a windows application you can use pdfMachine Get yours now

حسينيان، حسن

بررسي رابطه فراسنجه هاي ارزيابي كيفيت فرآيند تبديل برنج اصفهان و خواص فيزيكي و مكانيكي آن

سازندگي، نوگران،سرخه , DOM , برنج قهوه اي