SEMI-SOLID FAT BY INTERESTERIFICATION OF RED PALM OIL WITH OTHER VEGETABLE OILS

Interesterification of appropriate blends of vegetable oils offers an alternative method for obtaining semi-solid fats without hydrogenation. Random interesterification was carried out on blends of different oils, namely palm oil and sunflower oil (8:2, 7:3 and 6:4 w/w), palm oil and rice bran oil (8:2 and 7:3 w/w), palm oil and coconut oil (9:1 and 6:4 w/w), as well as palm oil and soybean oil (7:3 w/w), in the presence of sodium methoxide as a catalyst (0.2% w/v). The melting characteristic of the interesterified fat obtained from a blend of refined red palm oil and sunflower oil blend, in the ratio of 4:1 (w/w; slip melting point 41C) indicated that this combination could be an ideal margarine fat base.     

Optical, magnetic and structural characterization of Zn1 − x Co x O nanoparticles synthesized by solvothermal method

Nanoparticles of Co-doped ZnO with 3·8, 7·2 and 11·5 wt% were synthesized by solvothermal method through oxalate precursor route. X-ray diffraction studies showed the formation of hexagonal ZnO structure for x?= 0·038, however, secondary phase of Co₃O₄ arises on increasing the Co content up to 11·5%. Transmission electron microscopic studies showed that particles are in the nano-metric regime and the grain size decreases on increasing the Co concentration. Optical reflectance measurements showed an energy bandgap, which decreases on increasing Co concentration. Specific surface area of these nanoparticles was found to be very high and comes out to be 97·6, 112·1 and 603·8 m²g^???1, respectively. All the solid solutions showed paramagnetism with weak antiferromagnetic interactions. It is seen that the antiferromagnetic interaction increases on increasing Co concentration.     

QUALITY OF FRESH-CUT TOMATOES

Tomato fruit at pink or light-red stages of ripening were cut into slices, rinsed with water containing 50 μL.L⁻¹ sodium hypochlorite and drained. They were stored in perforated polyethylene package at 1C in air or controlled atmosphere for five and ten days. Weight loss, chlorophyll and lycopene contents, seed discoloration, fungal infection, total soluble solids content, titratable acidity, sugar/acid ratio, pH, flavor and taste, firmness, ascorbic acid content, rate of respiration and ethylene production, and electrolyte leakage were evaluated after each storage period. The overall quality of controlled atmosphere-stored slices was better than that of air stored slices. Slices from light-red fruit had lower weight loss, minimum seed discoloration, lower     

ASSESSMENT OF OXIDATION IN HEATED SAFFLOWER OIL BY PHYSICAL, CHEMICAL AND SPECTROSCOPIC METHODS

Safflower oil was heated at 180C by static heating in an open pan or in an oven, or by heating through intermittent heating-cooling cycles (as in frying) over a period of 8 h. The extent of deterioration of the oil was followed by measurement of physical characteristics such as color and viscosity and the chemical indices such as free fatty acid, peroxide, iodine, conjugated diene and triene values, unsaponifiable matter and oxidized fatty acids. The extent of oxidation was also assessed by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopic techniques through analysis of oxidized fatty acids. The results indicated that heating in open pan caused deterioration in oil faster than in other treatments. Furthermore, the IR, and NMR studies of the oil heated in an open pan indicated cross polymerization while during oven heating and frying cross polymerization was not observed.     

UNSAPONIFIABLE MATTER AND OXIDATIVE STABILITY OF COMMERCIALLY PRODUCED INDIAN RICE BRAN OILS

Chemically and physically refined rice bran oils (RBO) were investigated for their content and composition of unsaponifiable matter and oxidative stability. The chemically and physically refined rice bran oils contained 2.6 and 4.5% unsaponifiable matter, respectively. The content and composition of unsaponifiable matter for chemically and physically refined RBO were phytosterols, 0.96%and 1.40%; 4-methyl sterols, 0.51%and 1.12%; triterpene alcohols, 0.52% and 0.86%; and nonpolar components, 0.61% and 1.13%, respectively. The corresponding oxidative stability for the two oils were 2.80 h and 4.37 h, respectively. The content of unsaponifiable matter was influenced by residual amounts of wax and oryzanol in the refined oil as shown by the model experiments. Thus physical refining of rice bran oil requires a thorough dewaxing step to obtain a refined oil without haziness and with a lower amount of unsaponifiable matter.