The aim of this study was to determine the concentrations of alpha- and gamma-tocopherols in human breast milk samples from different periods of lactation and to compare them with tocopherol content in commercially available formulas for infants at corresponding ages. The study included 93 breast milk samples obtained on the 2nd (colostrum, n = 17), 14th (n = 30), 30th (n = 27) and 90th day of lactation (n = 19), along with 90 samples of commercially available initial and follow-on infant formulas. Concentrations of tocopherols were determined using normal-phase high-performance liquid chromatography. Depending on the stage of lactation, human breast milk contained 2.07-9.99 mg L⁻¹ of alpha-tocopherol and 0.22-0.60 mg L⁻¹ of gamma-tocopherol. Breast milk concentrations of alpha-tocopherol decreased with the time of lactation, while significant differences in gamma-tocopherol concentration were observed only between the 14th and 30th day of lactation. There was no significant correlation between the dietary intake of vitamin E and its estimated breast milk concentration, also in women who declared vitamin supplementation. Compared with colostrum, infant formulas were characterised by significantly lower concentrations of alpha-tocopherol and vitamin E. This finding indicates the need of additional vitamin E supplementation of bottle-fed infants during the initial 2-3 days of life.

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The content and composition of lipids in different byproducts (skins, heads, and backbones) from mechanically processed farmed Atlantic salmon were determined and compared with that obtained from wild salmon. Three different procedures were used to establish the optimal conditions of oil extraction (at high temperature −95°C, “cold” extraction at temperature not exceeding 15°C and enzyme assisted with Alcalase). “Cold” extraction at temperature not exceeding 15°C was very efficient, yielding almost 95% of the oil from skins. In the case of heads the obtained yield of about 71% was not lower than that from extraction performed at 95 °C or extraction supported by enzyme treatment. The peroxide value of oil isolated from the heads using “cold” extraction was at the same level as in oil of the enzyme assisted process, but four times lower than in oil extracted at high temperature. The results showed that the content of lipids from in the farmed salmon byproducts the content of lipids was about 45–55% higher than in byproducts of wild salmon, however the EPA + DHA content was 10–33% lower. Practical applications: With “cold” extraction heating which is commonly used for oil recovery in the fish industry could be eliminated and thus the cost of the process would be lower and oxidative changes in the oil reduced. Furthermore, this method based on rules of “green chemistry” can be more attractive and alternative procedure of oil isolation from fatty fish byproducts than those using organic solvents. The fatty fish byproducts such as heads, skins, and backbones may be used as a source of valuable oils rich in PUFA. The remaining material after oil isolation can be a source of collagen and gelatin used in the food, pharmaceutical, and cosmetic industries and finally of minerals preparation (in the case of heads and backbones) used for enriching animal feed. The oil was extracted from salmon byproducts: heads, backbones, and skins by using different methods. Conventional extraction of the oil at high temperatures ensures high yield but leads to low quality of the product. Enzymatic extraction is more preserving to oils rich in polyunsaturated fatty acids, but has special requirements. An attractive solution can be the “cold” extraction. This procedure allows achieving the oil from fatty fish byproducts with high yield and quality in a simple and cheap way.