Terpenoids, a diverse and complex chemical group, are lipidtype molecules important to flavours and aromas of seasonings, herbs and fruits. Most terpenoids are multi-cyclic compounds made via successive polymerisation and cyclisation reactions derived from the 5-carbon building block isoprene, which contains two double bonds. Terpenoids are components of the flavour profiles of most soft fruit (Maarse 1991).
Colour is an intrinsic property of foods, and therefore, a change in colour is often caused by a change in quality. Vision is the most important sensory perception in selecting food and appreciating its quality (Diehl 2008). Chlorophylls are the most abundant natural pigments and are responsible for the green colour of plants (Marquez Ursula and Sinnecker 2008) and are the biomolecules responsible for capturing light energy in its transformation into chemical energy during photosynthesis.
Light is able to be absorbed very efficiently due to the presence of many conjugated double bonds within the large, multi-ring chlorophyll structure. Disappearance of chlorophyll during fruit ripening and leaf senescence indicates slowing of photosynthesis. The loss of green colour is due to a loss of chlorophyll structure via two main stages: First, various reactions produce greenish chlorophyll derivatives and second, oxidative reactions result in opening of ring structures, thereby causing colourless products (Diehl 2008).
Cholesterol is an important lipid in animal biochemical processes that controls the fluidity of membranes and is the precursor for all steroid hormones. Cholesterol’s structure is made up of adjacent carbon rings, making it hydrophobic (fat soluble), and thus it must be transported through the blood complex as a lipoprotein in structures called chylomicrons.