Application of a Novel Instantized Glycerol Monooleate Ingredient in a Protein-Stabilized Oil-In-Water Emulsion.

Glycerol monooleate (GMO), casein and whey proteins are surfactants that can stabilize emulsion systems. This study investigates the impact of instantized GMO powders on creaming stability and oxidative stability in protein-stabilized emulsions. Model emulsions with bulk GMO, two instantized GMO powders, and two controls (without GMO) were produced by microfluidization. The droplet size, ζ-potential, viscosity, and creaming index of the emulsions were measured, while oxidative stability was evaluated by analysis of volatile compounds during storage (28 days, 45 °C) using gas chromatography mass spectrometry. Emulsions with GMO produced smaller average droplet sizes (180.0 nm) with a narrower distribution (polydispersity index of 0.161) compared to the controls (197.6 nm, 0.194). The emulsion stability of instantized emulsions was as good as bulk GMO, which were both better than controls. Based on the relative abundance of 3-octen-2-one, 2,4-heptadienal isomer 2, and 3,5-octadien-2-one isomer 1, the oxidative stability of the instantized emulsions was not significantly different from controls; however, bulk GMO emulsion showed significantly lower stability than controls. Instantized GMO powders can successfully produce physically stable protein-stabilized emulsions with good oxidative stability in a convenient powdered format.

Effect of milk protein composition on physicochemical properties, creaming stability and volatile profile of a protein-stabilised oil-in-water emulsion.

Casein, whey proteins and monoglycerides are emulsifiers that adsorb at the oil-water interface to form and stabilise emulsions. This study aims to understand the effect of different milk protein compositions (ratio of sodium caseinate and whey protein concentrate (WPC)) with glycerol monooleate (GMO) on physicochemical properties, creaming and oxidative stability of the emulsions. Model emulsions with five different protein compositions were prepared by microfluidisation. The physicochemical properties were characterised by droplet size, zeta potential, viscosity and creaming index. Oxidative stability was assessed using volatile lipid oxidation compounds during ageing (28 days at 45 °C). Results showed that the emulsion with only sodium caseinate produced smaller droplets (174.7 nm), higher zeta potential (-50.8 mV) and a more viscous emulsion (1.89 mPa s) compared to the emulsion with only WPC (191.4 nm; -38.8 mV; 1.65 mPa s). Protein composition had no significant effect on creaming stability. Eleven volatile compounds were identified as lipid oxidation markers and six compounds (2-pentylfuran, octanal, nonanal, 3-octen-2-one, 2,4-heptadienal, 3,5-octadien-2-one isomers) demonstrated that emulsions with mixed protein types (sodium caseinate and WPC) had better oxidative stability than emulsions with a single protein type. Therefore, mixed proteins with GMO form stable emulsions with both good physicochemical properties and oxidative stability.

A high performance liquid chromatography method for determination of furfural in crude palm oil.

A modified steam distillation method was developed to extract furfural from crude palm oil (CPO). The collected distillates were analysed using high performance liquid chromatography (HPLC) coupled with an ultraviolet diode detector at 284nm. The HPLC method allowed identification and quantification of furfural in CPO. The unique thermal extraction of CPO whereby the fresh fruit bunches (FFB) are first subjected to steam treatment, distinguishes itself from other solvent-extracted or cold-pressed vegetable oils. The presence of furfural was also determined in the fresh palm oil from FFB (without undergoing the normal extraction process), palm olein, palm stearin, olive oil, coconut oil, sunflower oil, soya oil and corn oil. The chromatograms of the extracts were compared to that of standard furfural. Furfural was only detected in CPO. The CPO consignments obtained from four mills were shown to contain 7.54 to 20.60mg/kg furfural.