Quality characteristics of edible vegetable oil blends

Two edible oil blends, namely groundnut oil:rice-bran oil and mustard oil:rice-bran oil, were prepared in different proportions and stored for a period of three years. Their physicochemical characteristics were determined. The results agreed with expected values except for free fatty acid percents and butyrorefrac-tometer readings, presumably due to rancidity. Fatty acid compositions of the blends were determined and ratios of characteristic fatty acids, like lignoceric to palmitic for groundnut oil:rice-bran oil blends, and erucic to palmitic for mustard oil:rice-bran oil blends, were calculated to identify individual oils in the blend.     

Development of chemically interesterified healthy coconut oil blends

Edible vegetable oil blends, such as coconut:linseed; coconut:safflower; coconut:sunflower; coconut:rice‐bran oils; in the ratio of 70:30 and 60:40 v/v and pure coconut oil (CNO) were interesterified using sodium methoxide 0.5% and subsequently refined to prepare nutritionally superior flowable CNO blends which remained liquid even at sub‐zero temperatures. The slip melting point of chemically interesterified fats could not be determined as they are liquified just after removing from freezing chamber in comparison with the slip melting point of 21.5–26.5 °C for their uninteresterified counterparts. These interesterified fats were liquid and flowable at 6 °C for more than 4 h in a cooling chamber and their solidification temperature ranged between ?2.0 and ?5.5 °C. Free fatty acids showed an increasing trend from 0.35% to 2.0% resulting in decrease in triglycerides After refining these oil blends showed values similar to their controls. However, iodine value of interesterified and uninteresterified oils were close to each other. Differential scanning calorimetry showed the onset of crystallisation at lower temperatures and lower solid fat content for interesterified fats. A nutritionally superior combination of CNO blend which is flowable at low temperature could be prepared.     

Oxidative Rancidity in Refined Sunflower Oil with Respect to Storage Variation

Refined sunflower oil was stored in brown and colorless glass bottles at ambient temperature (18–32°C) and 37°C to assess the effect of light, heat and air on the stability fo the oil and to record the progress of oxidative rancidity especially the secondary stages with respect to storage variation and time. Oil sample stored in brown color bottle was found to be superior (FFA 0.15 to 0.53; PV 0.5 to 80; HV 3 to 12; oxirane oxygen 0.2 to 2.3) over oil stored in colorless bottle (FFA 0.15 to 0.60; PV 0.5 to 91; HV 3 to 8; oxirane oxygen 0.1 to 2.8) at ambient temperature. Samples stored at 37°C deteriorated very fast. Silver nitrate test, oxidised fatty acid formation, urea adduct formation, picric acid-TLC test, Kreis test, DNP-TLC test, DNP-precipitation test have been devised to detect and follow oxidative rancidity. These tests worked well even at the lower levels of oxycompounds. No conjugation was detected in any of the oil.     

Methods for Detection of Rice-Bran,Mustard, Karanja Oils and Rice-Bran Deoiled Cake

Methods have been developed to detect rice-bran (Oryza sativa), mustard (Brassica sp.) and karanja (Pongamia glabra) seed oils in other edible vegetable oils, and deoiled rice-bran cake into other deoiled oilseed cakes. The methods depend on the presence of oryzanol in rice-bran oil, isothiocyanates in mustard oil, karanjin, karanjone, pongaglabrone and pongamol in karanja oil, and acylsteryl glycoside in deoiled rice-bran cake. Rice-branoil and karanja oil may be detected by TLC and mustard oil can be detected in a test tube by developing a green colour complex.     

Derivatization of keto fatty acids: I. Synthesis and mass spectrometry of thiazolidinones

The synthesis of alkyl chain-substituted thiazolidinones from oxo acids is described. Reactions of mercaptoacetic acid with three oxoesters, methyl 10-oxoundecanoate, methyl 12-oxooctadecanoate and methyl 9,10-dioxooctadecanoate gives excellent yields of the corresponding thazolidinones. Mass spectral fragmentation patterns of these long-chain thiazolidinone derivatives are discussed. Presented at the ISF/AOCS World Congress, 1980, New York.     

Addition of N,N-Dibromobenzenesulfonamide to Methyl Oleate,Elaidate and trans-2-Hexadecenoate II

Addition of N,N-dibromobenzenesulfonamide (NNDBS) to methyl cis/trans-9-octadecenoales and methyl trans-2-hexadecenoate afforded the corresponding vicinal dibromides, bromohydrins and threo/erythro α-bromo-N-benzenesulfonamide adducts. The isomeric threo/erythro-9(10)-bromo-10(9) - (N-benzenesulfonamido) octadecanoate were inseparable mixtures, while the 2(3)-bromo-3(2)-(N-benzene-sulfonamido) hexadecanoates were separated by column chromatography. The configuration of threo and erythro adducts was established by their conversion to cis-and trans-aziridines. Structures of the products were established by spectral studies.     

Leucas urticaefolia Seed Oil - A Rich Source of Laballenic Acid

As a part of our continuing screening programme of unusual fatty acid containing seed oils it was observed that the oil of Leucas urticaefolia seeds contains an allenic acid (24 %) which was characterized as 5,6-octadecadienoic (Laballenic) acid by using spectral and chemical degradation methods.     

Studies on Herbaceous Seed Oils XI

Seeds from eight species were analysed by standard procedures for oil and protein contents. The fatty acid composition of the oils was determined by GLC. Five species were found to contain oils above 20% and none of them is rich in protein. Some of the oils have a composition fairly similar to the oils at present in common use. Five seed oils are interesting in having more than 50% of saturated acids of the total fatty acids. T. involucrata seed seems to be a promising species because of its high oil and linoleic acid (61.7%) contents.     

Evaluation of the turbidity and thin layer chromatographic tests for detection of castor oil

Detection procedures for castor oil in genuine and treated groundnut oils were screened and false turbidity was noticed when ammonium molybdate/sulfuric acid reagents were added to rancid groundnut oil. Successively bleached and neutralized rancid groundnut oil samples do not respond to the tests. Turbidity did not appear for groundnut oils containing 10 and 20% castor oil and even for pure castor oil sample. Thin layer chromatography (TLC) was found to be quite effective for most of the treated, adulterated, genuine, old and fresh oil and fat samples, but showed a streaking, when applied to rancid groundnut oil. However, streaking could be greatly reduced and TLC could be successfully performed with bleached and neutralized, rancid groundnut oil samples.