Effects of dietary n-3 polyunsaturated fatty acids and ... - FINS

1 st WorkshopXIII International Feed Technology SymposiumINFLUENCE OF INDICATOR PARTICLE SIZE ON THE MIXEREFFICIENCY EXAMINATION RESULTSRadmilo Čolović, Đuro Vukmirović, Slavica Sredanović, Olivera Đuragić, DušicaIvanov, Bojana KokićInstitute for Food Technology, Bulevar cara Lazara 1, 21 000 Novi Sad, SerbiaABSTRACTAchieveing mixture homogeniety is one of the basic objects in feed production. Now adays, usage of colored iron tracer particles is the most used method for mixer efficiencyexamination. Three different granulation of “microtracers” were used in this paper: FS, Fand RF. Mixing efficiency of rotary drum shape additive mixer was examined for threedifferent mixing time. The aim of this experiment was examination of influence ofvarious tracer particle size on results of mixing efficiency testing. It is fortified that withincreasing of mixing time, segregation of mixture appeared when FS and F tracers wereused. With RF tracers, totally opposite results were obtained.Key words: homogeneity, mixing, tracers, particle size distributionINTRODUCTIONMixing is one of the most important unit operations in feed production process. Mainobjective in the mixing process is to produce a mixture in which probability of findingany component particle is the same in all positions in the mixture, but ideal mixing is notpossible to achieve. If feed is not properly mixed, single portions will contain eithermore or less ingredients than it is formulated. These variations in feed composition cancause animal illnes, and, thus, economic losses to animal producers. Periodic routinemixer testing is very important from the aspect of safety, but also from economic andethic point of view, especially for premix production. Different substances, includingamino acids, microminerals and salt have been used as tracers to measure feed mixingefficiency. For many years, the colored iron tracer particles, which can be separated fromthe rest of feed magnetically, have been successfully used in practice. These iron-basedproducts, from the Microtracers TM company, are including following tracer types,differed by size distribution and number of particles per gram: 1. Microtracer F (ColoredIron grit, 25.000 particles per gram); 2. Microtracer FS (Colored Stainless steel grit,50.000 particles per gram); 3. Microtracer RF (Colored iron powder > 1.000.000particles per gram). Microtracers can be detected and quantified by using RotaryDetector - laboratory magnetic separator, or by use of special magnetic probe [1, 2, 5, 6,7]. The size uniformity of various ingredients that comprise finished feed can directlyimpact on final ingredient distribution. If physical properties of ingredients are relativelythe same, then mixing becomes fairly simple, but if physical characteristics ofingredients differ more, blending and segregation problems become complex [4]. The177