Genetically modified food : Edible, Edible, Edible antibodies

Genetically modified food

The greater concern in food biotechnology is the integration of both modern biological knowledge and techniques and current bioengineering principles in food processing and preservation. Modern biotechnological techniques will have considerable importance in influencing trends in the food market, namely cost, preservation, taste, consistency, colour and above all, health aspects.

Every year more than a million children die and another 3,50,000 go blind from the effects of vitamin A deficiency. Employing genetic engineering techniques, Potrykus of Switzerland and Peter Beyer of Germany transferred genes that make carotene in daffodils into Oryza sativa. Ordinary techniques of plant breeding do not offer a way to enrich the crop.

Extracting carotene genes from daffodils, Potrykus and Beyer had introduced these genes into the soil bacterium. Agrobacterium tumefaciens, the transgenic agrobacteria were then incubated with rice embryos in plant tissue culture medium. As the bacterium infects the rice cells, they also transfer the genes for making beta carotene.

A number of examples are available where transgenic plants suitable for food processing have been developed.

(i)       Tomatoes with elevated sucrose and reduced starch could also be produced using sucrose phosphate synthase gene.

(ii)    Starch content in potatoes could be increased by 20 to 40 per cent by using a bacterial ADP glucose pyrophosphorylase gene (ADP GPPase).

(iii)  Vaccines, antibodies and interferons can be consumed directly along with tomato, banana and cucumber.

Edible vaccine

Acute watery diarrhoea is caused by Escherichia coli and Vibrio cholerae that colonize the small intestine and produce enterotoxin. Attempts were made to produce transgenic potato tubers that they could still retain vaccines in their tubers, even after the tubers had become 5 per cent soft after boiling. 50 per cent of vaccine was still present in the tubers.

Edible antibodies

Transgenic plants are being looked upon as a source of antibodies. They can also provide passive immunization by direct application.

Edible interferons

Interferons are the substances made of proteins and are anti-viral in nature. Scientists have successfully produced transgenic tobacco and maize plants that secrete human interferons . Today, rice crops have been enriched with vitamin A through gene manipulation. Similarly, pulse crop have been tampered with to produce lysine-rich pulse seeds. Such genetically modified food (GMF) are now becoming components of human staple food.

It is hoped that one day genetically engineered plants will have one or more of these attributes:

i.          They will show tolerance against heat, cold, drought or salt.

ii.        They are more nutritious.

iii.     They can be stored and transported without fear of damage.

iv.     They require less fertilizer.

v.        They produce chemicals and drugs that are of interest to humans.