Varietal Differences in Physical and Milling Properties of Paddy Grains

ABSTRACT: Physical and milling characteristics of paddy grains are important in many problems associ at ed wi t h t he desi gn, devel opment as wel l as t he anal ysi s of t he behavi or of t he agri cul t ur al pr oduct s duri ng post -harvest processi ng. I n t hi s st udy some physi cal and mi l l i ng propert i es f or f i ve varieties of rough rice namely, Tarom, Khazar, Fajr, Nemat and Neda were determined. The results reveal ed t hat rough ri ce of Nemat vari et y has t he hi ghest mean l engt h, wi dt h, equi val ent di amet er, gr ai n vol ume and surf ace area. The Tar om vari et y regi st ered t he l owest l engt h, t hi ckness, equi val ent di amet er and vol ume; whi l e t he maxi mum t hi ckness bel onged t o Neda vari et y. The aver age val ues of aspect rat i o and spheri ci t y f or t he f i ve t est ed vari et i es were 0. 22 and 34%, respect i vel y. The bul k densi t y f or of Neda was si gni f i cant l y di f f erent f rom t he ot her f our vari et i es. There was no si gni f i cant di f f erence i n t he angl e of repose among di f f erent vari et i es. The hi ghest st at i c coef f i ci ent of f ri ct i on was obt ai ned on mi l d st eel sur f ace, f ol l owed by r ubber and gal vani zed mi l d st eel . I n t er ms of mi l l i ng pr opert i es, t her e was a si gni f i cant di f f erence bet ween some of t he t est ed paddi es. The hi ghest br oken mi l l ed ri ce was obt ai ned f or Nemat vari et y and t he l owest was bel onged t o Faj r. I n addi t i on, Nemat variety has the maximum weight of paddy and head brown rice compared to the other varieties.