Influence of Emulsifiers and Dairy Ingredients on Manufacturing, Microstructure, and Physical Properties of Butter

Analytics and applications of polyglycerol polyricinoleate (PGPR)-Current research progress

Polyglycerol polyricinoleate (PGPR) is a synthetic food additive containing a complex mixture of various esters. In recent years, there has been a growing trend to use PGPR-stabilized water-in-oil (W/O) emulsions to replace fat in order to produce low-calorie food products. In this respect, it is essential to comprehensively characterize the PGPR molecular species composition, which might enable to reduce its required amount in emulsions and foods based on a better understanding of the structure-activity relationship. This review presents the recent research progress on the characterization and quantitative analysis of PGPR. The influencing factors of the emulsifying ability of PGPR in W/O emulsions are further illustrated to provide new insights on the total or partial replacement of PGPR. Moreover, the latest progress on applications of PGPR in food products is described. Current studies have revealed the complex structure of PGPR. Besides, recent research has focused on the quantitative determination of the composition of PGPR and the quantification of the PGPR concentration in foods. However, research on the quantitative determination of the (poly)glycerol composition of PGPR and of the individual molecular species present in PGPR is still limited. Some natural water- or oil-soluble surfactants (e.g., proteins or lecithin) have been proven to enable the partial replacement of PGPR in W/O emulsions. Additionally, water-dispersible phytosterol particles and lecithin have been successfully used as a substitute of PGPR to create stable W/O emulsions.

Preparation of Antarctic Krill Oil Emulsion and Its Stability under Catalase Treatment

Making Antarctic krill oil into emulsion is a good way to utilize Antarctic krill, but proliferation of microorganisms cannot be ignored. H₂O₂ is widely used in the sterilization of liquid food since its decomposition products are environmentally friendly, although residual H₂O₂ should be removed for food safety. Adding catalase (CAT) is an effective means to do this. However, the enzyme activity center of CAT is the iron porphyrin group, which has the risk of accelerating lipid oxidation in the oil emulsion. Therefore, we hypothesized that CAT might not be suitable for the removal of H₂O₂ in Antarctic krill oil emulsion. In this paper, Antarctic krill oil emulsion was prepared, and then the effect of CAT on the emulsion was studied through visual observation, microscopic morphology observation, turbidity and stability, particle size, and ζ-potential; finally, the mechanism of CAT destroying the emulsion was explored from the perspective of lipid oxidation. The results showed that a stable Antarctic krill emulsion was prepared using Tween-80 as the emulsifier, with the oil concentration of 1% (v/v) and the ratio of surfactant to oil phase of 1:5 (v/v). The emulsion treated with CAT had undergone demulsification, stratification, and coagulation after 2 days of incubation, while the emulsion treated with superoxide dismutase (SOD) and bovine serum albumin (BSA) changed little. In addition, the thiobarbituric acid reactive substances (TBARS) value and the content of hydroxyl radicals in the CAT group increased significantly. The preliminary research results indicated that the effect of CAT on the emulsion related to the lipid oxidation caused by the iron porphyrin group at the center of the enzyme activity. All these results indicated that CAT was not suitable for the removal of residual H₂O₂ in Antarctic krill oil emulsion. Moreover, it is helpful to avoid the contact of Antarctic krill oil emulsion and CAT during the processing of the krill.