The obtaining of natural preservatives, flavours, colorants or aromas are of great interest because the low temperature used in the process avoids the destruction of thermolabile compounds.
But there is another important market in the food industry, the extraction of actives compounds such as carotenes or poly-unsaturated fatty acids. These compounds added to food increase their nutritional value.
However it's not the only way to enrich food, I've found and article about "Biofortified" food. The use genetic manipulation allows producing vegetables with high levels of vitamins or other micronutrients. The main doubt, apart from the general aversion produced by "genetically modified" words, was whether the nutrients are bioavailable.
A recent publication, report that carrots genetically engineered to accumulate twice as much calcium as control carrots are indeed a good source of this essential nutrient, resulting in a 50% increase in calcium absorption .
Then we are between nutrition and pharmacology and in the field of novel foods which deals with food safety and a lack of clear legislation. Morris J. & cols. PNAS 105 (2008) 1431