Short communication: Effects of dietary deoiled soy lecithin supplementation on circulating choline and choline metabolites, and the plasma phospholipid profile in Holstein cows fed palm fat

Dietary lecithin is a source of choline. Our objective was to evaluate the effects of dietary deoiled soy lecithin feeding on circulating choline, choline metabolites, and the plasma phospholipid profile in lactating dairy cows fed fractionated palm fatty acids. In a split-plot Latin square design, 16 Holstein cows (160 ± 7 d in milk; 3.6 ± 1.2 parity) were randomly allocated to a main plot receiving a corn silage and alfalfa haylage-based diet with palm fat containing either moderate or high palmitic acid content at 1.75% of ration dry matter (moderate and high palmitic acid containing 72 or 99% palmitic acid in fat supplement, respectively; n = 8/palm fat diet). Within each palm fat group, deoiled soy lecithin was top-dressed at 0, 0.12, 0.24, or 0.36% of ration dry matter in a replicated 4 × 4 Latin square design with 14-d experimental periods. A 14-d covariate period was used to acclimate cows to palm fat feeding without lecithin supplementation. Blood sampling occurred during the final 3 d of each experimental period. Plasma choline and choline metabolites were quantified using liquid chromatography and mass spectrometry. Plasma phospholipids were profiled using time-of-flight mass spectrometry. Whereas no effects of treatments were detected for plasma choline or methionine, lecithin feeding increased the plasma concentrations of choline metabolites trimethylamine N-oxide and dimethylglycine (24 and 11%, respectively). Plasma phosphatidylcholine (PC) and sphingomyelin (SM) concentrations increased with deoiled lecithin feeding (e.g., PC 16:0/22:6 and SM d18:1/18:3). Lecithin supplementation also increased plasma lysophosphatidylcholine (LPC) concentrations (e.g., LPC 18:0) while reducing plasma phosphatidylethanolamine (PE) concentrations (e.g., PE 16:0/20:5). Although increases in microbial-derived trimethylamine N-oxide suggest gastrointestinal lecithin degradation, elevations in plasma dimethylglycine, PC, LPC, and SM suggest that choline availability was improved by lecithin feeding in cows, thus supporting enhanced endogenous phospholipid synthesis.

Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat

Deep-fat frying is an important process used worldwide for the preparation of foods. Due to oxidation, hydrolysis, decomposition and oligomerization, numerous polar compounds are formed. These compounds change the physical, nutritional and sensory properties of the oil or fat. The standard methods of the German Society for Fat Science for the assessment of the quality of frying fats are time consuming and cost intensive. Therefore, alternative cost-effective and sensitive rapid methods, which ideally allow the quantitative determination of the quality of frying fats “in-line” in the deep-frying pan are needed. Sunflower oil and palm fat were thermally and oxidatively degraded in a beaker at atmospheric pressure under intensive stirring for 76 h at 175 °C. To evaluate the development of the physical properties during heat treatment, the viscosity and dielectric constant of these oils were measured. The temperature in a deep-frying pan can vary within a wide range (160–190 °C), and the viscosity and dielectric constant show a strong temperature dependence. Therefore, it was necessary to measure the temperature dependence of the viscosity and dielectric constant of the different degraded oils. Additionally, their chemical properties were characterized by high-performance gel permeation chromatography and Fourier-transform infrared spectroscopy (FTIR). The determination of the dielectric constant, which is directly correlated with the concentration of polar compounds, seems to be the best method for the assessment of the quality of used frying oils.

Physical compatibility between wax esters and triglycerides in hybrid shortenings and margarines prepared in rice bran oil

BACKGROUND

Wax esters contribute to the transformation of liquid oils into solid-like oleogel systems, which can act as alternatives for trans- and/or saturated fats in food products. The use of solely waxes reduces the solid content, consistency and sensory quality in the final products. Therefore, a combination of sunflower wax and palm fat in rice bran oil was created to accomplish the hybrid low-saturated shortenings and margarines with a compatible structure and lower amounts of saturated fats.

RESULTS

During cooling of the hybrid shortenings, sunflower wax crystallized first and acted as nucleation sites for the crystallisation of palm fat. At 5 °C, a mixture of different crystal morphologies (α, β', and β crystals) existed in the hybrid shortening. In margarine processing, the hybrid samples were subjected to a simultaneous cooling-emulsification, in which sunflower wax crystallised first at the interface and adsorbed onto the water droplets. Based on the hardness measurements, the maximum amount of palm fat replaceable by 1.0%wt sunflower wax was up to 40% in shortenings and 25% in margarines. A higher amount of sunflower wax (2.5%wt) reduced up to 40% of saturated fats in the hybrid emulsions.

CONCLUSION

The addition of 1.0%wt sunflower wax enhanced the solid content and network strength of hybrid palm-based shortenings. Sunflower wax helped to stabilise the water droplets inside the wax-based crystalline network without flocculation during shear-cooling. This research provides fundamental insight into the structuring of hybrid systems containing waxes, which could be interesting for the production of low-saturated fat products in the food industry. © 2017 Society of Chemical Industry.