Sergey Bylikin, Gary Horner and, Brian Murphy Solutions for Chapter: Biochemistry, Exercise 5: Questions

Chocolate is a luxury food made from cocoa, sugars, unsaturated vegetable fats, milk whey, and emulsifiers. Bars of chocolate sold in hot climates are made with a different blend of vegetable fats from bars sold in cold climates.

Suggest how the structure of fat molecules used in a hot climate might differ from those used in a cold climate.

Food shelf life is the time it takes for a particular food stuff to become unsuitable for eating because it no longer meets customer or  regulatory expectations. As a result, in many parts of the world, packaged foods have a date before which they should be consumed.

State the meaning of the term rancidity as it applies to fats.

Food shelf life is the time it takes for a particular food stuff to become unsuitable for eating because it no longer meets customer or  regulatory expectations. As a result, in many parts of the world, packaged foods have a date before which they should be consumed.

Rancidity in lipids occurs by hydrolytic and oxidative processes. Compare the two rancidity processes.

A student carried out an experiment to determine the energy value of $100.00 \mathrm{g}$ of a food product by burning some of it. A $5.00 \mathrm{g}$ sample was burned and the heat produced was used to hear water in a glass beaker. She recorded the following data:

Mass of water heated$=100.00 \mathrm{g}$. 

Initial temperature of water$=19.2 °\mathrm{C}$.

Highest temperature of water$=28.6 °\mathrm{C}$.

Heat capacity of the glass beaker$=90.2 \mathrm{J} {\mathrm{K}}^{-1}$.

Specific heat capacity of water$=4.18 \mathrm{J} {\mathrm{g}}^{-1 }{\mathrm{K}}^{-1}$.

Calculate the energy value for $100.00 \mathrm{g}$ of the food product, in $\mathrm{kJ}$, showing your working. 

Countries have different laws about the use of synthetic colourants in food. Explain why this can be dangerous for the consumer.

Discuss the responsibilities of governments, industry, and individuals in making healthy choices about diet and maintaining a balance between the protection of public and individual freedom.

Draw the formula of a glycerophospholipid containing the residues of palmitic and linoleic acids.

Deduce the equation for the complete saponification of this glycerophospholipid.