A simple and rapid colorimetric method was developed to determine the lipase activity for fat splitting Free fatty acids produced by lipase from triacylglycerols were determined by observing the color developed using cupric acetate-pyridine as a color developing reagent This modified method requires only a few minutes to determine the free fatty acids, whereas it takes over 20 min by the conventional methods which require solvent evaporation and centrifugation steps The sensitivity and reproducibility of the method were good for caproic, caprylic, capric, lauric, myristic, palmitic, stearic and oleic acids

A simple and rapid colorimetric method for determination of free fatty acids for lipase assay

Crude vegetable oils are usually oxidatively more stable than the corresponding refined oils. Tocopherols, phospholipids (PL), phytosterols, and phenols are the most important natural antioxidants in crude oils. Processing of vegetable oils, moreover, could induce the formation of antioxidants. Black cumin (Nigella sativa L.), coriander (Coriandrum sativum L.), and niger (Guizotia abyssinica Cass.) crude seed oils were extracted with n-hexane and the oils were further fractionated into neutral lipids (NL), glycolipids (GL), and PL. Crude oils and their fractions were investigated for their radical scavenging activity (RSA) toward the stable galvinoxyl radical by electron spin resonance (ESR) spectrometry and toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical by spectrophotometric method. Coriander seed oil and its fractions exhibited the strongest RSA compared to black cumin and niger seed oils. The data correlated well with the total content of polyunsaturated fatty acids, unsaponifiables, and PL, as well as the initial peroxide values of crude oils. In overall ranking, RSA of oil fractions showed similar patterns wherein the PL exhibited greater activity to scavenge both free radicals followed by GL and NL, respectively. The positive relationship observed between the RSA of crude oils and their color intensity suggests the Maillard reaction products may have contributed to the RSA of seed oils and their polar fractions. The results demonstrate the importance of minor components in crude seed oils on their oxidative stability, which will reflect on their food value and shelf life. As part of the effort to assess the potential of these seed oils, the information is also of importance in processing and utilizing the crude oils and their byproducts.

Radical scavenging activity of black cumin (Nigella sativa L.), coriander (Coriandrum sativum L.), and niger (Guizotia abyssinica Cass.) crude seed oils and oil fractions.

Structure and occurrence of unusual fatty acids in minor seed oils

Recent developments in tetrazole chemistry. a review

Attack or defend! A smart polymer surface has two reversibly switchable equilibrium states, a cationic N,N-dimethyl-2-morpholinone (CB-Ring) and a zwitterionic carboxy betaine (CB-OH). CB-Ring will kill bacteria upon contact under dry conditions, whereas CB-OH will release the previously attached and dead bacteria and further resist adhesion of bacteria under wet conditions.

Reversibly Switching the Function of a Surface between Attacking and Defending against Bacteria

Seed oils ofSida acuta andSida rhombifolia were found to contain sterculic (110, 108%) and malvalic (17, 20%) acids respectively, in addition to the normal fatty acids Co-occurrence of these acids was established by gas liquid chromatography of the silver nitrate-methanol-treated methyl esters usingSterculia foetida esters as a reference standard This gas liquid chromatography technique of quantitation was found most suitable to estimate these acids in low level cyclopropenoid acid-containing seed oils

Cyclopropenoid fatty acids in seed oils ofSida acuta andSida rhombifolia (malvaceae)

Eriolaena hookeriana seed oil: A rich source of malvalic acid

Methyl 4-oxo-trans-2-octadecenoate (II), when treated with excess hydrazoic acid in the presence of BF3-etherate, produced 66% methyl 5-aza-nonadec-trans-2-enoate (4,5-d)-tetrazole (III), 10% methyl 5-aza-nonadec-4-oxo-trans-2-enoate (IV) and 7% pentadecamide (V). Individual products were characterized by spectral and elemental methods.

Synthesis of tetrazole from α,β-unsaturated carbonyl fatty acid

Seed oils ofGnetum scandens (Gnetaceae) andSterculia pattens (Sterculiaceae) were found to contain sterculic (28.57,6.97) and malvalic (11.27,3.87) acids, respectively. Gas Chromatographic analysis of silver nitrate/meth-anol-treated methyl esters was used to establish the co-occurrence of these two acids.Sterculia foetida methyl esters were used as a reference standard.

Cyclopropenoid fatty acids ingnetum scandens and itsterculia pallens seed oils

Alkyl chain substituted oxathiolanes from allylic oxo are described. Reaction of methyl 4-oxo-trans-2-hexadecenoate (1) with β-mercaptoethanol yields methyl 4-oxathiolane-trans-2-hexadecenoate (II), methyl 4-oxathiolane-2(3)-(S-β-mercaptoethyl acetate) hexadecanoate (III) and methyl 4-oxathiolane-2(3)-(S-β-mercaptoethanol)hexadecanoate (IV).

M. S. Ahmad

Papers

Cyclopropenoid fatty acids in seed oils ofSida acuta andSida rhombifolia (malvaceae)

Eriolaena hookeriana seed oil: A rich source of malvalic acid

Synthesis of tetrazole from α,β-unsaturated carbonyl fatty acid

Cyclopropenoid fatty acids ingnetum scandens and itsterculia pallens seed oils

Synthesis of sulfur heterocycles from α,β-unsaturated carbonyl fatty acid esters