The reactions of N-succinimidyl benzoates (1) with aliphatic primary amines (2) in acetonitrile or dioxane gave the corresponding N- (arylcarbonyl) amines (3). Reverse phase HPLC analysis of (3) was performed at 210300nm detection wavelengths using acetonitrile containing 070vol% of water as the mobile phase. Plots of log (corrected retention volume : V) vs. carbon number (CN) of alkyl group in (3) showed good linear relationship. The slope of the log V vs. CN plot increased with water content in the mobile phase. An interaction between the aryl group in (3) and the reverse phase appeared to occur in consideration of the result in which it was affected by water. The relative response of (3) at 254nm was found to be correlated linearly with the molar absorptivity of (3) at 254nm. The separation of labelled butylamines was also examined.
The synergistic antioxidant effects of d-tocopherol (Toc) and several spicy compounds on lard and plam oil were investigated by oven and AOM tests. The antioxidant effects of spicy compounds were also studied in the same manner. 1) By the oven test, cinnamaldehyde, capsaicine and thymol showed weak antioxidant effect on lard, but spicy compounds which enhanced the antioxidant effect of Toc were capsaicine, cineol, camphene, phellandrene and geraniol. However, no effect was observed on palm oil. 2) By the AOM test, only capsaicine showed antioxidant effect on lard, but none of the spicy compounds enhanced this effect of Toc. 3) Remnant ratios of the spicy compounds after a month of the oven test were lower than 30%, except in the case of capsicine which may possibly volatilize after such a period of time. However, the ratios of capsaicine and thymol which had antioxidant effects were higher than those of other compounds on lard. The remnant ratio of total Toc in lard increased by the addition of capsaicine, cineol, camphene, phellandrene or geraniol, indicating these compounds to possibly protect Toc from oxidative decomposition.
An automated colorimetric method based on continuous flow analysis has been developed for determining free fatty acids in fats and oils and their derivatives. A 2-propanol solution of a sample was directly introduced into a Technicon Auto Analyzer. o-Nitrophenylhydrazine (ONPH) solution and N-ethyl-N'- [3- (N'', N'' methylamino) propyl] carbodi-imide (EDC) solution containing 5% pyridine were added to the sample solution, followed by heating at 60°C for 12min. The free fatty acids in the sample were converted the corresponding o-nitrophenylhydrazides. The solution was mixed with 1% KOH solution to decrease the absorbance of the reagent blank, followed by measurement at 550nm. The method provides a common molar response to a series of fatty acid from caprylic acid to oleic acid. The sample capacity of themethod is 2040 samples/h. Its reproducibility is within 1% relative and recovery, from of 97100%. It was successfully used for determining lipase activity and quantitating free fatty acids in various fatty acid derivatives.
Amino acid compositions and sulfur content of dry keratin hydrolysate and its fractions obtained by membrane ultrafiltration were determined. Remarkable differences were found in amino acid compositions and sulfur content between the fraction of molecular weight from 500 to 1, 000 and the other fractions. The ferrous salt FeSO4 (NH4) 2SO4·6H2O (Mohr's salt) or ferric solution of Fe2 (SO4) 3xH2O was added at the same concentration to an aqueous keratin hydrolysed solution and its fractions. The ultraviolet and visible absorption spectra of the hydrolysed protein solutions to which ferric solution had been added were the same as those to which the ferrous salt had been added, when concentrations of Fe (II) and Fe (III) were equal. From the above results for absorption spectra and change in the colors of Fe (III) added hydrolysed protein solutions into which 1, 10-phenanthroline solution had been introduced, it is apparent the mercapto group (-SH) containing keratin hydrolysed proteins has reducing activity and can reduce Fe (III) to Fe (II) in hydrolysed protein solutions. Also, the keratin hydrolysate and its fractions were shown to be connected to Fe (II) in a water-soluble chelate configulation in a pH range from 7.0 to 7.5, 25°C.