As the global population and its demand for seafood increases more of our fish will come from aquaculture. Farmed Atlantic salmon are a global commodity and, as an oily fish, contain a rich source of the health promoting long-chain omega-3 fatty acids, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Replacing the traditional finite marine ingredients, fishmeal and fish oil, in farmed salmon diets with sustainable alternatives of terrestrial origin, devoid of EPA and DHA, presents a significant challenge for the aquaculture industry. By comparing the fatty acid composition of over 3,000 Scottish Atlantic salmon farmed between 2006 and 2015, we find that terrestrial fatty acids have significantly increased alongside a decrease in EPA and DHA levels. Consequently, the nutritional value of the final product is compromised requiring double portion sizes, as compared to 2006, in order to satisfy recommended EPA + DHA intake levels endorsed by health advisory organisations. Nevertheless, farmed Scottish salmon still delivers more EPA + DHA than most other fish species and all terrestrial livestock. Our findings highlight the global shortfall of EPA and DHA and the implications this has for the human consumer and examines the potential of microalgae and genetically modified crops as future sources of these important fatty acids.

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Impact of sustainable feeds on omega-3 long-chain fatty acid levels in farmed Atlantic salmon, 2006-2015.

The oil palm tree is an ancient tropical plant that originated from West Africa. Palm oil has centuries׳ long use as food and medicine. This review covers the recent significant materials found in the literature on palm oil processing, refining, and use in frying especially in blends with other vegetable oils. Crude palm oil (CPO) is obtained from the fruit of the oil palm tree (Elaeis guineensis). The oil is rich in palmitic acid, β-carotene and vitamin E. CPO has been fractionated mainly into liquid palm olein and solid palm stearin in order to diversify its food applications. Palm oil is highly stable during frying especially due to the synergistic activity of β-carotene and tocotrienol. In recent years there has been a shift from the use of animal fats and hydrogenated vegetable oils in frying and other food applications. The use of naturally stable oils such as palm oil and composite oils like blends of palm oil and other fats and oils is practiced to ensure that maximum benefits are derived from the oils. Blending offers functional, nutritional and technical advantages, such as tailoring the oil to suit frying applications. The objective of this review is to combine and condense the body of research on the processing, characterization and use of palm oil especially in frying as well as suggest areas that need further research.

Palm oil: Processing, characterization and utilization in the food industry – A review

Ass's milk yield and chemical composition were investigated in two lactations at d 28, 45, 60, 75, 90, 105, 135 and 150 after parturition. Milk yield per milking (averaging 740 mL) of 6 asses of Martina Franca (n = 3) and Ragusana (n = 3) breeds, which quickly adapted to the milking machine procedures, increased in the second (or third) milking per day but was unaffected by stage of lactation or breed. Year of lactation, stage of lactation, breed and milking time did not influence the gross composition of the milk, except for fat and protein contents. The overall average protein percentage (1.72 g·100 g-1 of milk), showing a significant negative trend throughout lactation, was characterised by low casein (47.3% of crude protein) and whey protein contents (36.9% of crude protein). A specific whey protein profile was also found, being the relative percentage on total whey protein 4.48%, 6.18%, 29.85%, 21.03% and 22.56% for respectively lactoferrin, serum albumin, β-lactoglobulin, lysozyme and α-lactoalbumin. The low average fat content of ass's milk (0.38 g·100 g-1 of milk), showing a high individual variability, was significantly affected by the year of the study; the lipid fraction was also characterised by high levels of linoleic (average 8.15 g·100 g -1 of total fatty acids) and linolenic acid (average 6.32 g·100 g -1 of total fatty acids). The ash content of ass's milk (0.39 g·100 g -1 of milk) was constant throughout the experimental period and showed high levels of Ca and P, the ratio of which, ranging between 0.93 and 2.37, was on average 1.48. ass's milk / protein / fatty acids / minerals

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Composition and characteristics of ass's milk

The development of methods for analyzing fatty acids that provide rapid and reliable results is currently in great demand. Recently, different lipid extraction procedures such as microwave or supercritical fluid extraction have been researched. Both procedures avoid the use of large volumes of solvents and provide rapid lipid isolations. Only a few papers have reported work on microwave extraction, but many studies about supercritical fluid extraction have been carried out and have been gaining acceptance within the scientific community. Avoiding the lipid isolation step, by synthesizing fatty acid esters by simultaneous lipid extraction and derivatization through in situ reactions, has also been proposed. The saving of time and reagents is significant. Owing to the differences among the procedures, some knowledge of their characteristics is essential in order to improve methods and achieve reliable and accurate results. Clearly, results depend on factors such as the type of catalysis selected, the use of nonpolar solvents, heating applied during the synthesis, and the degree of suitability of the procedure chosen for the particular features of each sample.

Development in lipid analysis: some new extraction techniques and in situ transesterification.

One-step method for quantitative and qualitative analysis of fatty acids in marine animal samples

A. Introduction B. Acid-Catalysed Esterification and Transesterification 1. General mechanism 2. Methanolic hydrogen chloride 3. Methanolic sulfuric acid 4. Boron trifluoride-methanol 5. Other acidic catalysts C. Base-Catalysed Transesterification 1. General mechanism 2. Sodium and potassium methoxide catalysts 3. Organic base catalysis D. Diazomethane and Related Reagents 1. Diazomethane and methyl ester preparation 2. Preparation of UV-absorbing and other derivatives E. Pyrolysis of Tetramethylammonium Salts of Fatty acids for the Preparation of Methyl Esters F. Preparation of Esters and Amides via Activated Fatty Acids 1. Acid halides 2. Fatty acid anhydrides 3. Imidazolides 4. Other coupling reagents G. Reaction of Alkyl or Aryl Halides with a Base 1. Derivatives for gas chromatography 2. Phenacyl esters and other derivatives for high-performance liquid chromatography H. Alternative Methods for the Preparation of Esters, Amides and Other Fatty Acid Derivatives 1. Dimethylsulfate with dicyclohexylamine 2. Preparation of esters with alkyl formamide derivatives 3. Trimethylsilyl esters 4. Preparation of pyrrolidides from esters 5. Preparation of hydroxamic acid and related derivatives 6. Reaction with Grignard reagents I. Special Cases 1. Short-chain fatty acids 2. Fatty acids with unusual structures 3. Sphingolipids and other N-acyl lipids 4. Sterol esters 5. Selective esterification of free fatty acids in the presence of other lipids J. Preparation of Esters in the Presence of Adsorbents for Thin-Layer Chromatography K. Simultaneous Extraction from Tissues and Transesterification L. Artefacts of Esterification Procedures M. The Choice of Reagents a Summary

William W. Christie

Papers

Preparation of ester derivatives of fatty acids for chromatographic analysis