Effects microencapsulation on physical and chemical characteristics, fatty acid profile, and oxidative stability of fish and sunflower oil compared with Ca- salts

Background and Objectives: The extremely high sensitivity of unsaturated fatty acids to oxidation and the problems related to their storage and consumption in liquid form are among the most important obstacles to the use of these resources in feeding farm animals, along with problems such as extensive biohydrogenation and adverse effects on the normal functioning of the rumen ruminants.. So the aim of this study was to determination of spray dry microencapsulation effects on fatty acid profile and nutrient content, physical and chemical characteristics and oxidative stability of fish and sunflower oil, compared with ca-salts in vitro.
Materials and Methods: In this research, a completely randomized design was used in the statistical analysis of the data related to the chemical composition, physical properties, and oxidation parameters after the production of the fatty acid sample in order to statistically analyze the data related to the oxidation resistance of various types of encapsulated supplements. In time, temperature and different levels of minerals, a factorial design based on a completely random design was used. Microcapsules produced with different oil sources (free fatty acids vs. triacylglycerol of fish and sunflower oil), different wall material systems (Physical blend of carbohydrate and protein sources vs. Maillard reaction products of them) and different ratio of core oil to wall materials. Fish and sunflower oil were added to the initial mixture with ratios of 1:2, 1:1 and 2:1 (coating materials to oil). In addition to glycerol oils, oil-in-water emulsions were also prepared from fish and sunflower fatty acids. To dry the emulsions, a spray dryer was used with an inlet air temperature of 130°C and an outlet temperature of 60-70°C. Determining the amount of nutrients (fat, dry matter, organic matter, calcium, different parts of the cell wall, different carbohydrate and protein parts and fat extraction, making methyl ester and determining the pattern of fatty acids) in the composition of microcapsules produced using Standard procedures were performed. The particle size of the produced emulsions and powders was determined using the laser diffraction technique. Microcapsules and calcium salts of fish oil and sunflower were exposed to temperatures of 25 and 60 degrees for 15, 30 and 45 days, and every two weeks one sample of each supplement was analyzed in order to evaluate the amount of peroxide value. For each supplement, 3 replicates were evaluated at each time and temperature.
Results: Emulsions made from triacylglycerol's have higher stability over time compared with FFA sources and were used for spray drying and further analysis. Different oil sources (fish oil vs sunflower oil) have no effects on microencapsulation efficiency, microencapsulation yield. However, wall material system has its effects. Maillard reaction products had higher encapsulation efficiency than physical blends and resulting microcapsules had higher microencapsulation efficiency, lower oxidative state parameters and more preserved fatty acid profile. Encapsulation with Maillard reaction products resulted in more oxidative stability in different storage conditions (different time and temperatures, with or without mineral stimulated oxidation), but the core oil type and ratio to wall materials affect the results. Sunflower oil gives the more oxidative stability than the fish oil, but higher the oil content of microcapsules, higher the oxidation. Oil content also significantly affects fatty acid profile of microcapsules. Results showed that fatty acid Ca- salts had highest oxidative protection between protection strategies.
Conclusion: Although microencapsulation protected oils from oxidation, incomplete data about nutrient availability, nutritional value and gastrointestinal tract digestibility of microencapsulated oils compared with a large data set about Ca-salt, warrants further in vivo studies.