Physical properties, fats margarines

Zhang H, Smith P, Adler-Nissen J. Effects of degree of enzymatic interesterification on the physical properties of margarine fats Solid fat content, crystallization behavior, crystal morphology, and crystal network. J Agric Food Chem. 52(14) (2004) 4423-4431. 

Fats provide fundamental structural and textural attributes to a wide range of consumer products, including lipstick, chocolate, and everyday products such as butter and margarine (1, 2). Within these fat-based products, certain textural properties are required to meet desirable sensory attributes to gain consumer acceptance (3). This has led to an increase in research efforts on the physical properties of fats, particularly their rheology. 

Refined camelina oil was blended into fat phase to produce margarines and spreads enriched in omega-3 fatty acids. The resulting spreads had physical properties similar to a product based on typical commercial oils. The stability of the new product was satisfactory, and off-flavors were not detected after 6 months of storage (76). 

Testing techniques for the evaluation of physical properties and other properties of finished margarine products as well as low-fat spreads have been stated to include (4, 91) appearance, oral melting characteristics, oil exudation, slump (collapse), penetrations, spreadability, emulsion viscosity at 35°C (95°F), emulsion drop size, and electrical conductivity. 

Neuronal membranes contain phospholipids. A lack of essential fatty acids, such as omega-3 fats, or excessive intake of saturated fats, margarine, cholesterol, and animal fatty acids, can result in abnormalities. The neuronal cell membrane regulates the passage of molecules into and out of the cell. Neuronal membrane fluidity is believed to impact behavior, mood, and mental function. Physical properties, including the fluidity, of neuronal membranes affect neurotransmitter synthesis, signal transmission, uptake of serotonin and other neurotransmitters, neurotransmitter binding, and the activity of key enzymes that break down neurotransmitters like serotonin, epinephrine, dopamine, and norepinephrine. 

Commonly used interesterified fats, whieh provide suitable fimctionality for the food industry, include fats that are rich in the long-ehain SYK, palmitic acid (16 0) and stearic acid (18 0) [77]. Chemical and enzymatic interesterification has been specially used in the formulation of margarines and shortenings to provide products with no TFA but that still maintain physical properties, taste, and stability [80]. 

Interesterification procedures are used industrially to improve the physical properties of lard, to produce cocoa butter substitutes from cheaper oils (usually combined with hydrogenation and fractionation), to produce fats containing acetic acid, and to produce margarine of appropriate melting behaviour with a minimum content of trans acids and maximum content of polyene acids. This has been achieved, for example, by interesterification of soybean oil (80%) and fully hydrogenated soybean oil (20%). 

V D Souza, JM deMan, L deMan. Chemical and physical properties of the solid fat in commercial soft margarines J Am Oil Chem Soc 69 1198-1206, 1992. 

Fat fractionation as we know it today has its origins in the late nineteenth century with the invention of margarine in 1869. The secret was the careful crystallization of freshly rendered edible tallow at temperatures between 25°C and 30°C [2]. The resultant grainy mass was then hydraulically pressed to obtain a crude 60 40 separation of a soft fraction (olein) and a hard fraction (stearin). This has remained the basic principle of the modern process. The softer fraction had physical properties similar to those of anhydrous milkfat (AMF) and was easily rendered into a plastic product that could be used in place of butter. 

Another parameter that influences the overall properties of the bulk emulsion is the physical state of the lipid droplets in an emulsion (17, 19, 28-31). Crystallization of lipid droplets in emulsions can be either beneficial or detrimental to product quality. Margarine and butter, the most common water-in-oil emulsions in the food industry, are prepared by a controlled destabilization of oil-in-water emulsions containing partly crystalline droplets. The stability of dairy cream to mechanical agitation and temperature cycling depends on the nature and extent of crystallization in milk-fat globules. It should be noted that because the density of the phases can change as crystallization occurs, the rate at which milkfat droplets cream can be altered as droplets solidify. Emulsion manufacturers should therefore understand which factors influence the crystallization and melting of emulsified substances, and be aware of the effect that droplet phase transitions can have on the properties of emulsions. 

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