Friday, July 8, 2011

Frying fat on deep fat -frying (part 2)

Antioxidants play an important role to prevent oxidation by reacting with oxygen so food component is protected. Antioxidants are commonly added to the food are BHA (Butylated hydroxyanisole), BHT (Butylated Hydroxy Toluene), and TBHQ (Tertiary Butyl Hydroquinone). Several studies have shown that TBHQ can protect the oil / fat better when compared with BHA or BHT in the frying process. Other components that also contribute to the stability of frying fat is citric acid and silicon metal or Dimethyl Polysiloxane (DMPS). Citric acid can act as a chelating (binding) the metal ions which are the catalysts of oxidation reactions.
DMPS function as anti-foam compound. The use of antioxidants TBHQ for frying fat is usually between 150-200 ppm, whereas the addition of DMPS optimum range 2-5 ppm. The role of DMPS is also associated indirectly with antioxidants, which the foam formation can accelerate oxidative deterioration. Some evaluations also showed that the use of DMPS is even more effective in preventing deterioration to the oil compared with the antioxidant BHT.
The products that have a high turnover such as in the industry of snack, does not require the use of anti-foam. But DMPS can cause problems in the attachment of the outer layer, such as the icing on the donut products, increase the absorption of oil, and reduces crispy texture of the product.
One way to maintain the quality of frying fat is the application of the top up procedure to the frying fats that have been used for several time. This relates to the term of slow oil turnover. Deterioration of oil in the frying of fast oil turnover is less, because the fresh oils / fats added continuously will stabilize the oil quality. In contrast to the frying of slow oil turnover, frying deterioration will be greater because only a little of the used frying fat old will be replaced with fresh frying fat. Increased free fatty acid content is used as an indicator of the extent of deterioration of frying fat.
Simple control of the quality of frying can be done by considering several factors such as discoloration, the formation of foam (foaming), smoke (smoking), changes in aroma and sensory evaluation of the product. Foaming or excessive smoking can cause a fire hazard. Foaming caused by high amounts of polar glycerides, especially those containing high polymer, while the smoke caused by free fatty acids and other breakdown products of low molecular weight.
While the more accurately analysis is done by measuring the parameters of free fatty acids, total polar materials, and peroxide value. All three are components of the reaction of fat frying deterioration and its value increases with increasing the deterioration.
Some developed countries have some criteria when we should not use the frying fat or oil, such as if the water content> 3 g / kg; free fatty acid content of> 1 g / kg; peroxide value> 2 meq / kg; smoke point <170 Celcius degree; content of polar compounds> 25%; and polymeric compounds content> 10%.

Related archieves:
Frying fat on deep fat frying (part 1)
Acrylamide and brain cancer
Acrylamide in food product
Reducing acrylamide in fried food
Virgin coconut oil: processing, quality and benefits

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