Here you see again the first question. Taking into account that everything you learned so far about the methods for total fat extraction, which method do you think the laboratory used for total fat extraction of the biscuits?

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Not right, In the previous questions you have learned that biscuits contain fats that are occluded in the food matrix due to the baking procedures. The Folch method is not able to extract those occluded fats completely.

Not right. In the previous questions you have learned that biscuits are high in structural and occluded fats. The Soxhlet extraction provides an incomplete extraction when the amount of structural fats or occluded fats is high. So it is not likely that the Soxhlet extraction was used.

Right! Biscuits contain fats that are occluded in the food matrix. To extract these fats it is necessary to unlock the food matrix prior to the solvent extraction. Acid hydrolysis can be used to do this. Examples of these methods are the Schmid method and the Weibull method.

In the next part of this case you will discover if there is variation between laboratories with respect to the selected methods and the results of analyses. This will help you to get insight into the quality of total fat analysis.

Not right. In the previous questions you have learned that it is not likely that Alkaline hydrolysis was used to extract fats from biscuits. Alkaline hydrolysis (e.g. the Röse-Gottlieb method) is especially developed for milk. The method disrupts bonds between proteins and fats when fats are being emulsified. This method is too mild to extract occluded fats.

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Folch extraction

Soxhlet extraction

Acid hydrolysis

Alkaline hydrolysis

First figure out which method was used for this analysis. Below you can find information on frequently used methods. Take your time to study the information and answer the questions.