Milk fat depression (MFD) syndrome, a consistent decrease in milk fat content, is related to important changes in fatty acid composition due to feed imbalances and the consequent ruminal metabolism alteration. Milk produced in two different farming systems was compared: Holstein Friesian fed with unified in intensive production and Podolica raised on a pasture in an extensive system. Milk chemical characteristics and fatty acid composition were determined comparing milk with a normal fat level (>3.8%) to milk with a low fat level (<3.2%) in each breeding system. Holstein Friesian milk showed the decrease in trans-11 and increase in trans-10 C18:1 (shift from trans-11 to trans-10 C18:1) in low fat with respect to normal fat milk with a consequent decrease in the trans-11/trans-10 C18:1 ratio. Even conjugated linoleic acid (CLA), C18:2 cis-9, trans-11, was lower while CLA trans-10, cis-12 was higher in low fat milk than in normal fat milk from Holstein Friesian. These changes, that are indicators of MFD syndrome, were not found in Podolica milk between fat levels. Holstein Friesian milk showed less short-chain fatty acids (9.48 % vs. 11.05%, p < 0.001), trans vaccenic acid (C18:1 trans-11, 0.51% vs. 3.39%, p < 0.001), rumenic acid (CLA C18:2 cis-9, trans-11, 0.32% vs. 1.45%, p < 0.001) and total CLA (0.53% vs. 1.91%, p < 0.001) contents than Podolica milk. Further losses of these human healthy nutrients in low fat Friesian milk reduced the nutritional quality of the milk, while the milk from animals raised on the pasture was of better quality even when the level of fat was low.
The present study evaluates the contents in bioactive compounds, antioxidant activity, oil content and fatty acid composition of Capparis spinosa seeds. Samples were collected from 5 different habitats (AH: Ahar; KU: Kurdistan; U1, U2 and U3: Urmia) in Iran. The oil content in the seeds ranged from 16 to 27%. The predominant fatty acid was linoleic acid (45-50%) followed by oleic acid (30-39%), palmitic acid (2-8%) and stearic acid (2-3%). Total phenolic content (TPC) varied from 16.3 to 24.2 mg GAE/ g DW; total flavonoid content (TFC) ranged from 1.48 to 3.05 mg QE/g DW; and the antioxidant activity (DPPH assay) of the seeds was between 35 and 63%. The compounds obtained from different genotypes of C. spinosa seeds had different compositions, great antioxidant capacity and unsaturated fatty acids, and therefore could be a prospective source of natural bioactive molecules for the food and health industry.
The low saturated fatty acid content of rapeseed oil has resulted in it being classed as one of the most health-benefiting culinary oils. This study determines whether Irish rapeseed oils contain identical fatty acid profiles or whether distinct profiles exist between producers and producers’ successive oil batches. The fatty acid content of Irish rapeseed oils was determined in terms of the desirable MUFA and PUFA and saturated content of these oils. The fatty acid composition demonstrated significant differences in individual unsaturated fatty acid content, while total saturation had insignificant differences. Saturated fatty acid content ranged from 6.10 to 15.8%, while unsaturated fatty acids ranged from 84.20 to 90.10%. Moreover, individual fatty acid content exhibited significant differences (
). Oleic acid (C18:1), linoleic acid (C18:2), and stearic acid (C18:0) contents were considered significantly different from other fatty acids detected. The third successive batch from each producer exhibited lower oleic acid content, and the third batch contained higher linoleic acid content, at the same time maintaining a desirable unsaturated fatty acid composition. Studies suggest that differences in the fatty acid composition may be due to cultivation practices such as climate, soil composition, sowing and harvesting, processing techniques, and oxidation reactions.
Introduction. Modern food science needs new research of food emulsifiers, their composition, properties and effect on the structural characteristics of emulsions. It looks for modern technological solutions on how to select proper emulsifiers and their mixes to produce emulsions with different mass fractions of fat. The research objective was to study the effect of physical and chemical indicators of surfactants on the properties of food emulsions, as well as to develop practical recommendations for the selection of surfactants for various types of products.
Study objects and methods. The research featured model dairy fat emulsions and laboratory-made vegetable oil, as well as hard and soft mono- and diglycerides of fatty acids and lecithins. The emulsifiers were used to determine the melting point, fatty acid composition, iodine number, and solid triglyceride content at various temperatures. The melting point of emulsifiers was determined by fixing the melting temperature in a capillary oven. To identify the fatty acid composition, the methyl esters of fatty acids were subjected to the chromatogram method. After that, the separated components and their quantity were determined by the area of the peaks. The content of solid triglycerides in the emulsifiers was determined by the method of nuclear magnetic resonance. The hydrophilic-lipophilic balance was obtained from the manufacturer's specifications.
Results and discussion. The solid mono- and diglycerides appeared to have a high content of stearic and palmitic acids. Oleic acid predominated in soft monoglycerides; unsaturated fatty acids (linolenic and oleic) also predominated in the monoglycerides/lecithin complex emulsifier. Solid monoglycerides had a high content of solid triglycerides at 35°C (82.93%), which correlated with the high melting point (80°C) and the lowest iodine number (3 mg I2/100 g) of all the samples. The optimal ratio of vegetable oil and the emulsifier was defined empirically. The emulsifiers were dissolved in refined deodorized vegetable oil at 5–7°C above the melting point of the emulsifier. The resulting ratios were between 6:1 and 10:1. The samples of creamy vegetable spreads were obtained using the studied emulsifiers and their compositions in different doses and ratios. The crystallization temperature and phase transition time were determined when studying the process of emulsion overcooling. The article introduces a list of technological and physicochemical indicators of emulsifiers: the fatty acid composition, the degree of saturation, the melting point, and the content of solid triglycerides. By finding out the physicochemical parameters of emulsifiers, producers can vary the ratio of the components of emulsifying compositions to achieve the desired properties of food emulsions. The hydrophilic-lipophilic balance also proved to be an important index since the proportion of hydrophilic and hydrophobic groups in surfactants affects the type of emulsions and makes it possible to adjust the fat content of the finished product.
Conclusion. The research results can expand the theoretical foundations of food emulsions. The article contains scientifically grounded recommendations on how to select optimal surfactants. The research opens up prospects for further studies of emulsifiers and their effect on the quality of finished products.
Several polyunsaturated fatty acids are considered to have beneficial health effects, while saturated fatty acids and industrial trans fatty acids (TFAs) are linked to negative health consequences. Given the increased formation of TFAs during heating, many studies already investigated compositional changes in oils after prolonged heating or at extremely high temperatures. In contrast, our aim was to measure changes in fatty acid composition and in some health-related indices in edible oils after short-time heating that resembles the conventional household use. Potatoes were fried in palm, rapeseed, soybean, sunflower and extra virgin olive oils at 180 °C for 5 min, and samples were collected from fresh oils and after 1, 5 and 10 consecutive heating sequences. Regardless of the type of oil, the highest linoleic acid and alpha-linolenic acid values were measured in the fresh samples, whereas significantly lower values were detected in almost all samples following the heating sequences. In contrast, the lowest levels of TFAs were detected in the fresh oils, while their values significantly increased in almost all samples during heating. Indices of atherogenicity and thrombogenicity were also significantly higher in these oils after heating. The present data indicate that prolonged or repeated heating of vegetable oils should be avoided; however, the type of oil has a greater effect on the changes of health-related indices than the number of heating sequences.