Effect of Strong Electrolytes on Edible Oils Part 1: Viscosity of Sunflower Oil In 1,4- Dioxane at Different Temperatures

The viscosity of sunflower oil in 1,4-dioxane used as a diluent in the presence and absence of strong electrolytes (HCl, NaOH, NaCl) at different temperatures (298K to 323K) was accomplished. The viscosity of sunflower oil was found to increase with the increasing concentration and decreased with the increase in temperature. It was further observed that viscosity of sunflower solution in 1,4-dioxane increases under the influence of electrolytes. The values of Jones-Dole coefficient A and B were evaluated. The positive values of Bcoefficient increased with the rise of temperature. This led to conclusion that ion-solvent interactions increase and electrolytes such as HCl, NaOH and NaCl behave as structure breaker in sunflower-1,4-dioxane system. The change in the values of fluidity parameters such as (a, k, α1, α2, β, β*) with concentration of oil and temperature suggests that fluidity parameters are structural. The energy of activation (ΔEv), latent heat of vapourization (ΔLv) and molar volume of oil (Vm) were also calculated. Effect of electrolytes show that, the concentration of electrolytes increases the value of (ΔEv) and (ΔLv) whereas the value of molar volume (Vm) decrease with the concentration of oil and electrolytes. In brief, unsaturations of fatty acids of oil are responsible for the changes in the values of different parameters determined. The results for (ΔEv) and (ΔLv) are influenced by the concentration of sunflower oil. @JASEM The importance of oils and fats in human nutrition is well recognized (Salunkhe et al 1992). These form of vital components of many cell constituents are an important source of energy and act as a carrier of fatsoluble vitamins. Besides they contribute significantly as function of ingredients in improving the sensory characteristics of several process food products. The ingredients of oils are the glyceric compounds of glycols and fatty acids. They are usually triglycerides in which one molecule of glycerols has combined with three molecules of fatty acids with the elimination of three molecules of water. The three molecules of fatty acids are rarely of but one kind so that the glycerides are mainly mixed triglycerides. Monoglycerides may be present in fatty acids to varying percentage, diglycerides are more rarely present. Free fatty acids and unsaponificable matter e.g., sterols, fatty alcohols hydrocarbons coloring matter etc are also the part of fatty acids. The edible oils, which are in daily human use, include canola, soyabean, peanut, cottonseed, sunflower, mustard, palm oils etc. These edible oils are major energy source of the human and animal organism. The energy values of fatty acids depend on their chain length. It decreased with the reduction of carbon (C) atoms. C6-C8 fatty acids contain only 34 kJg whilst 38 kJg is obtained from the fatty acids containing C16-C18 atoms (Shama 2004). The main aim to revise the importance of edible oils for the use of human diet is to find out the effect of electrolytes like HCl, NaOH and NaCl, which are some how the others are related to digestion of human food. What happens when these electrolytes come in contact with edible oils? The effect of these electrolytes is studied on the viscosities of oil solution as a function of electrolytes concentration and temperature. The viscosities are measured in 1, 4-dioxane. The oil selected, for this study is extracted from the seeds of sunflower. EXPERIMENTAL Material: 1,4-dioxane (BDH), HCl, NaOH, NaCl, oxalic acid of E. Merk were used without further purification. Oil of sunflower was extracted from dried and dehulled seeds. Sunflower seeds were bought from the local market in Karachi, Pakistan. Oil was extracted from washed, dried, dehulled and crushed sunflower seeds. Extracted oil was filtered and used without further purification. The density of oil at 298K was determined as 0.978 g.cm. Procedure: Experiments are accomplished to measure the viscosities and densities of oil solutions in 1,4-dioxane in the presence of electrolytes. Viscosities of oil solutions in 1,4-dioxane are measured at different temperatures ranging from 298K to 323K with the help of Ostwald viscometer. Temperature was kept constant through out the course of experiment with the help of a thermostatic water bath type (circulator model YCM-01, volt 230Ac, Hz 50, Amp 5). A known fixed volume of oil *Corresponding author: E-mail: [email protected] Effect of Strong Electrolytes on Edible Oils Part 1 16 solution was taken in viscometer, temperature of the solution was maintained by placing the viscometer in the thermostatic water bath having a constant circulation of water. Densities of solvent and solutions were measured with the help of relative density bottle having a capacity of 10 ml by volume at different temperatures. Viscosities and densities were measured as a function of oil concentration, electrolytes concentrations and temperatures. Each measurement was recorded at least three times to ensure the reproducibility in the observations. RESULTS AND DISCUSSION Oil extracted from the seeds of sunflower is ensured from any impurity present in it. Density of this oil is measured at different temperatures by using relative density bottle. The density of oil changes slightly in the 3 decimal place with temperature difference 5K shown in Table 1. It shows that oil is thick and volume of oil up to temperature 323K spreads slowly and changes in unsaturation occur. Viscosity of oil solutions (5-25%) is measured in 1,4-dioxane at different temperatures ranging from 298K to 323K with the help of Ostwald type viscometer. The results are summarized in Table 2 and shown graphically in Fig. 1. These results reveal that viscosity of oil increases with increase in concentration of oil and gets decreased as the mercury level rises in Fig. 2. Fig. 1 : Plot of viscosity (η) (cp) of sunflow er oil versus % concentration. 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5