Influence of the selected factors on the liquid food density

Abstract

The density of materials can be used for assessing their quality. The density of food materials depends on temperature and is caused by thermal expansion during heating. The density of a material is defined as a ratio between the mass of the material and its volume at the same temperature. One of the most exact methods for measuring liquid density is the pycnometric method. Measurements of materials density could also be performed using hydrometers or densimeters, where the exact value of density can be discerned on the hydrometer scale or on the display of measurement devices. During our experiments, we used two methods of density determination: pycnometric method and determination by a densimeter Mettler Toledo DM 40. Measurements were performed in the approximate temperature range (0 -30) °C. The effect of various parameters (such as temperature, fat content, alcohol content and short storing time) on the density of the material was analysed in this paper. A linear decreasing character was applied for temperature dependencies of the sample density in the measured temperature range. The highest fat content of milk caused the lowest density, whereas lower fat contents (less than 1.5 %) were not consistent with this proportion due to different amounts of proteins in the measured samples of milk. The effect of the alcohol content on density had to be investigated alongside the material composition (wine, whisky and piña colada). The density values obtained were a bit higher after a short storage period due to the water loss during storage. REZIME Gustina materijala može se koristiti za procenu njegovog kvaliteta. Gustina prehrambenih materijala zavisi od temperature i izazvana je toplotnom ekspanzijom tokom zagrevanja. Gustina materijala je definisana kao odnos mase materijala i zapremina pri istoj temperaturi. Jedna od najtačnijih metoda merenja tečnosti je piknometrijska metoda. Merenje gustine materijala, takođe, može se obaviti pomoću hidrometara ili densimetara , pri čemu se tačna vrednost gustine može očitati na skali hidrometra ili na displeju mernih uređaja. Tokom eksperimenata korišćene su dve metode određivanja gustine: piknometrijska metoda i određivanje denzimetarom Mettler Toledo DM 40. Merenja su obavljena u približnom temperaturnom opsegu (0 -30) °C. U radu je analiziran efekat različitih parametara (kao što su temperatura tečnosti, sadržaj masti, sadržaj alkohola i kratko vreme čuvanja) na gustinu materijala. Linearno smanjenje karaktera je primenjeno za zavisnost gustine od temperature u mernom opsegu temperature. Najveći sadržaj masnoće u mleku uzrokovao je najmanju gustinu, dok sadržaj masnoće (manje od 1,5%) nije bio u skladu sa ovim sadržajem, zbog različitih količina proteina u izmerenim uzorcima mleka . Efekat sadržaja alkohola na gustinu moraose ispitati uz sastav materijala (vino, viski i pina kolada). Dobijene vrednosti gustine su bile malo veće nakon kratkog vremena skladištenja usled gubitka vode tokom skladištenja.