Emulsions Vegetable measurement

Colloid stability enters our daily life in many different ways. A visit to the kitchen provides numerous examples of food colloids with microstructure and stability that are, in no small measure, an important aspect of their appeal to the palate For example, mayonnaise —a mixture of vegetable oil, egg yolk, and vinegar or lemon juice —is an emulsion of oil in water and is stable because the lecithin molecules in the egg yolk provide the needed stability. Milk is another example. We have seen others in the vignettes in Chapters 1 and 4. 

Vegetable oil (none) or antioxidants in vegetable oil were added as ingredients in the raw meat emulsions for bologna manufacture. The antioxidants tested were 500 ppm sodium erythorbate (eiythorbate), 200 ppm sodium nitrite (nitrite), and 0.075% rosemary extract (rosemary). The emulsions were cased, cooked, and irradiated at 3 kGy. Volatile compounds measured die next day, and expressol as square root of peak ar count. The numbers were means of four replicates. Adopted from ref (26). 

The antioxidant activities of rosemary extracts, carnosol and camosic acid were also significantly influenced by the oil substrates and the type of system tested, bulk oils versus oil-in-water emulsions, the methods used to measure oxidation and the concentration of test compounds. The rosemary extracts, carnosol and camosic acid effectively inhibited hydroperoxide formation in com oil, soybean oil, peanut oil and fish oil, when tested in bulk (Table 9.12). The rosemary extract and pure constituents were more active antioxidants in bulk corn, peanut and fish oils than in bulk soybean oil. This difference may be attributed to the relatively higher concentrations of tocopherols in soybean oil that are known to have a negative effect on the antioxidant activity of rosemary constituents. Test compounds also inhibited hexanal formation in bulk vegetable oils, and propanal and pentenal formation in bulk fish oils. In marked contrast, these test compounds were either inactive or promoted oxidation in the corresponding vegetable oil-in-water emulsions. In fish oil emulsions, however, the rosemary compounds inhibited conjugated diene and pentenal formation, but not propanal. 

Palm oil represents about 23% of the world output of vegetable oils and is employed as a food fat in its bulk state, for example in shortening or in emulsions such as margarine and cream [75,76]. The effects of the addition of the SOEs (S-170, P-170, and 0-170) on palm oil in the O/W emulsion were studied by ultrasonic measurements [12], It was shown that S-170 and P-170 reduced the degree of supercooling and hence accelerated the nucleation, yet the effect of 0-170 was negligible. Table 3 shows the Tc of palm oil in bulk and in O/W emulsion, in which the was defined in the same manner as for n-hexadecane. In the bulk without impurities, Tc was 34°C. With the addition of 1 wt% P-170... 

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