Influence of extraction temperature on amounts and quality of rendered chicken fat recovered from ground or homogenized skin.
A study was undertaken to determine the influence of extraction process on recovery and quality of fat from chicken skin. In order to do so, 20-kg batches of skin were ground (9.5 mm plate) or homogenized in a colloidal mill (0.2-mm knife set), then heated to 50 or 80 C to rupture fat cells. The fat was recovered by centrifugation and was evaluated for composition, appearance, and stability. A maximum amount of fat (89.6% of the fat initially contained in skin) was recovered from homogenized skin heated to 80 C, whereas heating ground skin to 50 C yielded the lowest fat recovery (51.5% of skin fat content). In general, fat composition and appearance were little affected by extraction conditions, with the exception that the fat extracted from homogenized skin contained more (P < or = 0.001) unsaponifiable cell membrane constituents (0.17 to 0.20%), including antioxidant tocopherol fractions (10.3 microg/ml), than the fat extracted from ground skin (0.08% and 7.5 to 8.3 microg/ml, respectively). This difference likely contributed to the greater oxidative stability of the fat extracted from homogenized skin, which was observed in Schaal oven tests.
Piette
G
G
Agriculture and Agri-Food Canada, Food Research and Development Centre, St-Hyacinthe, Quebec. Pietteg@em.agr.ca
Hundt
M
M
Jacques
L
L
Lapointe
M
M
D000818:Animals; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D005223:Fats / Q000032:analysis*; D005504:Food Analysis; D005511:Food Handling / Q000379:methods*; D011202:Poultry Products / Q000032:analysis*; D012867:Skin / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014810:Vitamin E / Q000032:analysis
D005223:Fats; D014810:Vitamin E