each cookie prior to baking. The chips were positioned upside down,
so that the flat side of the chip was level with the cookie surface. The
cookies were baked in a conventional oven (Frigidaire) for 12 min at
325 °F. After baking, cookies were cooled at room temperature (approximately
22 °C) on a cooling rack lined with parchment paper
and stored on sheet trays at 20 °C for 10 days. A storage period of
10 days was chosen as it was adequate time for bloom to form on
chocolate chips without sacrificing the overall quality of the cookie.
Five individual batches of cookie dough were prepared for each fat
level and type. Five cookies from each batch were reserved for analysis.
One chip from each cookie was selected for analysis based on how
well it remained embedded in cookie dough during and after baking.
This resulted in 25 samples for each condition tested.
2.2. Temperature profile of chocolate chips during baking
To determine if crystal memory effect was the cause of bloom inhibition
on chocolate chips baked in cookies, it was necessary to verify
that chips melted completely during baking. This was determined
by observing the internal temperature of the chocolate chips during
baking using a thermocouple. A small hole was carved into the side
of the chocolate chip using a needle, and a wire temperature probe
was inserted into the hole. The chocolate chip was pushed into the
cookie dough with the point of the chip facing down, so that the flat
side of the chip was even with the dough. Special care was taken not
to dislodge the temperature probe. Samples were baked at 325 °F for
12 min. The chocolate chip temperature was recorded every minute
for the duration of the baking process.