South african fish products. Part XXVI. Application of the fitelson method of “squalene” determination to some marine oils

Abstract

estimated as calcium pectate and of extraneous ash, it will be seen that this object is best achieved (results of Experiments VIII and XII) by the process of first submitting the crude pectin extract to dialysis followed by precipitation by alcohol at a concentration of 70%. It will be noted, however, that in none of the experiments did the material estimated as calcium pectate reach a higher value than 7574 of the total solid matter.The problems relating to the nature of the residual 25'% of " ballast " material, and to its possible bearing on the gel forming properties of the pectin, are under investigation. It was demonstrated in all the experiments that this ballast material waS reduced more by precipitation than by dialysis, the ash, on the other hand, was removed more completely by dialysis than by precipitation. The value of ionic exchange bases for the purpose of removing ash is rather doubtful ; dialysis experiments demonstrated clearly that a small quantity of inorganic matter is combined with the pectin, while esperiments XIV and XV show that this combined ash may be removed, at least to a large extent, by the exchange bases. This removal is desirable if the inorganic matter is a fortuitous contamination of the pectin due to the method of extraction, but undesirable if it is a normal constituent in the sense that the methoxy groups are normal; in this connection it is noteworthy that the authors have examined many pectins from a wide range of fruits and vegetables which have been extracted under conditions which would render contamination with metallic ions unlikely, and in all cases have found a residual ash after dialysis.It will be noted that in none of the experiments which may be considered as having given maximum purification (namely, I and VIII, XI1 and XIV);did the sum of the saponification value, and free and combined acidic groups equal the theoretical value of 20.5% ; Hinton' found values ranging from 16.2% to 20.2% with an average value of 18.5% for a wide range of pectins, figures which are in good agreement with those reported. It would appear that a criterion of the purity of a pectin is the approach of this figure to the theoretical value of 20.5y0 (the fange 16.2% to 20.2% being regarded as satisfactory), combmed with an increase of the calcium pectate to a maximum. The copper reducingjpower;of the] pectin is of little value as a measure of thelpurification ; the values obtained are in agreement with those obtained by Hinton for the iodine reducing values (which ranged between 2.5% and 23'3%). Conclusion(a) Experiments carried out on the purification of crude Pectin solutions showed that dialysis followed by precipitation from aqueous solution by alcohol (70%) gave a pectin of the highest pectin content (determined as calcium pectate).(b) The process reduced the ash content to a minimum value of the order of 2-4% of the calcium pectatc value which, it is concluded, represents inorganic ions combined with some of the un-esterified carboxyl groups of the pectin.(c) Further reduction of t...

Amount of Squalene and Fatty Acid Composition of Triacylglycerols and Phospholipids in Flesh and Liver Lipids of Some Deep-sea Teleost Fish, Morid Cods and Whiptails

“…Squalene levels in unsaponifiable matters isolated from liver NL of the deep-sea teleost fish examined corresponded to 0.57 1.76% of the liver lipids. Squalene levels in liver lipids from H. johnsonii (1.76%), C. cinereus (1.43%), C. pectoralis (0.86%) and C. acrolepis (0.79%) were higher than those in the drumfish Sciaena hololepidota (0.41%), the cape eel Congermuraena australis (0.18%) and the angler fish Lophius pisatorius (0.12%) (24) Table 2 and Table 3 Differences in percentages of the component fatty acids were found between TG class in the livers and PL class in the flesh of the deep-sea teleost fish examined ( Table 2 and Table 3, respectively). The fatty acid composition of TG in the livers was different from those of PL in the flesh; the former tending to be more monoenoic (mean: 68.6%) with 22:1n-11 (20.1%), 18:1n-9 (13.7%), 20:1n-11 (10.2%), 16:1n-7 (6.9%) and 20:1n-9 (5.8%) acids, and the latter tending to be more polyenoic (40.5%) with 22:6n-3 (25.0%) and 20:5n-3 (8.8%) acids.…”

Composition of diacyl glyceryl ethers in the liver lipids of ratfish, Hydrolagus novaezealandiae.

“…Previous studies show that diacyl glyceryl ethers of the shark liver lipids are limited to a few genera of the Subclass Elasmo-branchii2-6). However, it is noteworthy that almost all ratfish reported hitherto have a much larger amount of the ether-linked lipids in the liver1, 3,[12][13][14][15][16][17][18] . The glyceryl ethers derived from diacyl glyceryl ethers of the H. novaezealandiae liver examined in this study were very similar in composition to those of the ratfish, Chimaera barbouril4), C. mon strosa16-18) and Hydrolagus colliei19).…”