N

FIGURE 7.23 Typical distributions of fat crystals found in milk fat globules.

Large Droplets Grow

Large Droplets Grow

FIGURE 7.24 Ostwald ripening involves the growth of large droplets at the expense of smaller ones.

Small Droplets Shrink

FIGURE 7.24 Ostwald ripening involves the growth of large droplets at the expense of smaller ones.

interface unhindered by the crystal network. When the emulsion is cooled, these crystals act as nucleation sites and crystal growth is restricted to the droplet surface. Thus L-type droplets are formed with large crystals located at the oil-water interface. This phenomenon is believed to be responsible for the increase in the rate of partial coalescence which occurs during temperature cycling of oil-in-water emulsions (Boode et al. 1991). The crystals at the interface in L-type droplets are larger and protrude farther into the aqueous phase and are therefore more likely to cause partial coalescence (Boode 1992).

In other types of food emulsions, there may be different crystal structures within the droplets than those shown in Figure 7.24. The crystal structure formed will depend on factors such as the chemical structure of the fat, the cooling rate, temperature cycling, the application of shear forces, droplet size distribution, the type of emulsifier used to stabilize the emulsion droplets, and the presence of any impurities that can poison or catalyze crystal growth. Further work is needed to elucidate the relationship between the morphology and location of crystals within emulsion droplets and their propensity to undergo partial coalescence.

Was this article helpful?

0 0
Atkins Low Carb Diet Recipes

Atkins Low Carb Diet Recipes

The Atkins Diet is here. Dr Atkins is known for his great low carb diets. Excluding, Dr Atkins carb counter and Dr Atkins New Diet Revolution.

Get My Free Ebook


Post a comment