Agricultural Academy

Abstract MENKOV, N. D., K. DINKOV, A. DURAKOVA and N. TOSHKOV, 2009. Sorption characteristics of buckwheat grain. Bulg. J. Agric. Sci., Moisture equilibrium data (adsorption and desorption) of buckwheat grain were determined using the static gravimetric method of saturated salt solutions at three temperatures 10, 25 and 40°C. The range of water activities for each temperature was between 0.11 and 0.85. Equilibrium moisture content decreased with increase in storage temperature at constant water activity. A suitable model was selected to describe the water sorption isotherms. The monolayer moisture content of the grain was estimated and the optimal storage water activity was proposed

INVESTIGATION OF PROCESS CHARACTERISTICS AND OF PRINCIPAL COMPONENTS OF ULTRAFILTRATION RETENTATES

ABSTRAC

PECULIARITIES OF THE HORSE MEAT AGING

Over the last decade the horse meat has gone deeper into the field of vision of both consumers and scientists. The objective of this study is to identify the specific features during aging of the horse meat. The changes in microstructure, morphology, protein autolysis, soluble proteins, pH, WHC, drip loss and colour were studied in horse m. Longissimus dorsi during 12 d of wet aging at 0 - 4°C. At 3 d post mortem the A- and I-zones were more difficult to distinguish. Some shortening of the sarcomere was observed. The rigor mortis period in the horse meat occurs between day 3 and day 5. Within this period the muscle fibres were contracted, the red colour component was decreased by 2 - 3 units, the pH and the WHC were minimal - 5.80 and 13 - 14%, respectively, and the drip losses were maximum about 20%. Intra-cellular spaces released free water was found. After 5 d post mortem single cracks and strains were observed - an indicator of the ongoing autolytic processes. The solubility of the proteins stabilized at about 1.750 mg/ml. An increased share of protein fractions with a molecular weight of 28 - 23 KDa, considered as an indicator of increased meat fragility, was found after 5 days. From 5 to 12 d, higher levels of α-actinin, deskman and light meromyosin were found. After 7 d of post mortem the destructive changes were deepening. Z-lines were very much torn. A- and I-discs were difficult to distinguish. Myofibrils were highly fragmented and I-zones were not distinguishable

Comparison of Empirical Models to Predict Viscosity of Secondary Vacuum Gas Oils

This work presents characterization data and viscosity of 34 secondary vacuum gas oils (H-Oil gas oils, visbreaker gas oils, and fluid catalytic cracking slurry oils) with aromatic content reaching up to 100 wt.%. Inter-criteria analysis was employed to define the secondary VGO characteristic parameters which have an effect on viscosity. Seven published empirical models to predict viscosity of the secondary vacuum gas oils were examined for their prediction ability. The empirical model of Aboul-Seud and Moharam was found to have the lowest error of prediction. A modification of Aboul-Seoud and Moharam model by separating the power terms accounting for the effects of specific gravity and average boiling point improves the accuracy of viscosity prediction. It was discovered that the relation of slope of viscosity decrease with temperature enhancement for the secondary vacuum gas oil is not a constant. This slope increases with the average boiling point and the specific gravity augmentation, a fact that has not been discussed before

Evaluation of the Different Compatibility Indices to Model and Predict Oil Colloidal Stability and Its Relation to Crude Oil Desalting

Thirty crude oils, belonging to light, medium, heavy, and extra heavy, light sulfur, and high sulfur have been characterized and compatibility indices defined. Nine crude oil compatibility indices have been employed to evaluate the compatibility of crude blends from the thirty individual crude oils. Intercriteria analysis revealed the relations between the different compatibility indices, and the different petroleum properties. Tetra-plot was employed to model crude blend compatibility. The ratio of solubility blending number to insolubility number was found to best describe the desalting efficiency, and therefore could be considered as the compatible index that best models the crude oil blend compatibility. Density of crude oil and the n-heptane dilution test seem to be sufficient to model, and predict the compatibility of crude blends