The effects of storage and process conditions on fat bloom formation in chocolate

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Effects of processing conditions and storage temperature on fat bloom formation in
chocolate were investigated in this study. Samples, chocolate coated cream filled with
crispy rice, were produced due to different temper indexes, (TI 5, 6, 7), shell thickness’
(1.5, 2.5, 3.5 mm), moulding rates (9, 12, 15, 18 mould/min) and storage temperatures
(18 and 28 °C). Samples were analysed along for 40 weeks due to acidity % as oleic
acid, peroxide value as meq O2/kg and crystal structure peaks at differential scanning
calorimetry (DSC) twice a month. Next; solid fat contents at nuclear magnetic resonance
(NMR) and fatty acid compositions as % at gas chromatography/mass spectroscopy
(GC/MS) in order to compare initial and final results to achieve verification with other
periodic analysis. Finally; shelf life of samples was determined.
Storage conditions were effective for delaying bloom formation on chocolate surface.
Storing chocolate samples at 28 °C instead of 18 °C caused a decrease in their shelf life
from 8 months to 5 months due to bloom formation. Slowly cooled chocolates in
chocolate production were more resistant to fat migration compared to fast cool-ones.
The shelf life of products with a cooling rate of 9 mould/min was observed to be 4
months higher than the chocolates with 18 mould/min. Shell thickness in chocolates
coated products was observed to be effective in delaying bloom formation. It was easier
to migrate cream oil from inner to outer surface for thin shell (1.5 mm) products,
whereas thicker one (3.5 mm) reached later to chocolate surface.