2.5. Triacylglycerol (TAG) analysis
Analysis of TAG profiles of chocolate chips baked in cookies and
sand, unbaked chocolate chips, palm oil shortening and olive oil
were obtained in order to verify and quantify oil migration during
baking. Chocolate chips were carefully scraped out of cookies and
sand–fat mixtures that had been stored for 10 days at 20 °C. The chocolate
was dissolved in petroleum ether and filtered through syringe
filters. TAG profiles were obtained using gas chromatography, courtesy
of ADM Cocoa, Milwaukee, WI. Two samples from each chip were
analyzed.
2.6. Degree of oil migration
To quantify oil migration occurring in cookies and sand mixtures,
degree of oil migration was calculated (Talbot, Smith, & Cain, 2006;
Talbot, Smith, & Zand, 2006) using TAG levels from fat in cookie
dough or sand/fat mixtures, and fat in chocolate chips before and
after baking (Eq. (1)). The degree of oil migration (DM) was calculated
for individual TAG. Average degree of migration was then calculated
by averaging the degree of migration values for all TAG (Eq. (2)).