Wednesday, November 11, 2015

Will tomato become the super source of natural food color, over shadowing its food value?

Fertilizers provide the backbone to modern agriculture and if world is still able to provide food to every denizen on this planet, thanks must go to the modern technology of food production. Yield of crops keeps growing without the need to expand cultivated areas. The success of the green revolution in India that enabled the country to become food self sufficient, was also possible by massive use of chemical fertilizers, that too at heavily subsidized price to the farmers by the government. After plateauing of the yield through chemical fertilizers, scientists zeroed on biotechnology processes like tissue culture and genetic engineering to further boost production though it is questionable whether these new techniques could really increase land productivity. Horticulture also followed the same route of chemical fertilizers and achieved high productivity over the years with many fruits and vegetables. After achieving increased productivity, most research developments concentrated on product quality suitable for the processors to provide better shelf life, reduction of handling wastage and adapting them to highly automated machines with huge through put capacity. Tomato is one fruit or call it a vegetable which has seen many developments in the hands of scientists since it is liked and used universally world over. Whether it is the intensity of color, firmness of the fruit or extended shelf life, tomato stands out as an unparalleled success to the scientists. 

Globally tomato production is estimated at about 165 million tons (mt) major producing countries being China (50 mt) and India (18 mt). Of course it is produced in every nook and corner of the world as it is a simple crop  that can be raised easily. There are about 7500 varieties of tomato with varying features and characteristics requiring different agroclimatic conditions though primarily it is a crop doing well in warmer climates. Surprisingly Netherlands and Iceland stand out among tomato producers boasting of yield as high as 476 t/ha and 429 t/ha while the global average yield is reported to be just 33.6 t/ha. This fruit is consumed in a variety of ways directly as well as in commercial products, most important ones being sauces, ketchup and paste. Use in different dishes and as a salad component also is substantial. The multitude of varieties evolved were based on conventional hybridization technology. Application of genetic engineering technology was attempted during the last three decades but without much success. The most "notorious" attempt, if one can call it, was to create a variety of tomato that can last long and can be handled with least damage through GMO technology. This effort ending up in the commercial development of the Flavr Savr brand in early nineties which conked out in the market.

Horticulturists must be given credit for developing new varieties through traditional breeding techniques with high color intensity as the lycopene content became a crucial issue in valuing the crop. Lycopene is important for both the consumer as well as the industry from health and value addition angles respectively. There was a time when synthetic colors predominated the market for supply to the food industry to manufacture a variety of food products with different bright and attractive colors with high consumer appeal. Then started the decline of synthetic colors with practically every one of them implicated in adverse health conditions for human beings through sustained use. Though the safety authorities tried to handle this emotional issue by progressively lowering the limit of use for these chemicals, eventually many of them exited from the safe color list during the last 3 decades. To day color additives are mostly derived from natural plant materials like safflower, blue grape, turmeric, hibiscus, tomato, carrots etc. Thus tomato color intensity is an important criterion for use in the edible natural color extraction.

It is against this background one has to view the recent attempt by a group of scientists in the US to develop newer techniques at the production level in the fields to enhance color of tomato. The new technique  involves the use of nano technology for delivering the most important mineral nutrient Zinc in a far superior way and increase the light capturing ability of green plants to boost the metabolic machine in the plant. Zinc is known to be an important micro nutrient for plants as it is involved in functioning of several critical enzyme systems related to growth but the efficiency of absorption through the root system from fertilizers applied to the land is considered very inefficient due to which plant metabolism is not fully functional to realize the potentials of growth it is capable of. Similarly the process of photosynthesis is one of the most inefficient one with the plants chlorophyll barely able to capture a fraction of the energy from the sun. The scientists discovered that infusing platinum into the plant can boost photosynthesis very significantly leading to spurt in growth. Based on these findings these scientists devised nano particle preparations which were found to deliver both zinc as well as platinum to the plant through foliar spray. 

When a plant needs nutrients it signals the soil about its needs and unfortunately the soil cannot deliver these nutrients in a way plant can assimilate. Here is where the ingenuity of the plant comes into play. It secretes its weapon in the form of enzymes to convert the fertilizer into actively usable nutrients in cooperation with a multitude of soil bacteria. But a typical plant can only absorb about 20 percent of the nutrients applied through soil through its root net work with the remainder either forming tough stable complexes with soil constituents or being washed away with water through runoffs Thus the nutrients are available to plants to a limited extent. If the new claims are proved true, the plants treated with the aerosol nanoparticles produce almost 82 percent more fruit by weight than untreated plants while these tomatoes had an increase lycopene content between 80 and 113 percent. It may be recalled that lycopene is a proven antioxidant that gives tomatoes and many red fruits and vegetables their red color with numerous studies linking it to reduced risk of cancer, though such claims are still to approved by the health authorities both in the US and the EU.

Though nano technology is a relatively new technology with great potential in almost all fields of human activity, there is some reservation in unleashing this technology in food and pharmaceutical fields. The obvious reason is the uncertainties surrounding its adverse impact on human health as nano sized particles are capable of by passing the human metabolic system and get into the body through physical absorption and circulation. So far no country has cleared use of nano technology in these areas for this reason. In the above studies also there is no clarity whether some of the nano particles sprayed on the plant leaves will end up in the fruits and there could be especially concern regarding the fate of platinum which is a heavy metal. Also the study has only indicated the yield increase in terms of percentage without revealing the figures of yield in the control plants. Whether the new technique can match the yields reported by giants like Netherlands and Iceland is some what doubtful. But even if it can raise the global average of just 33.6 t/ha significantly tomato industry can be expected to get a substantial lift in the coming years.


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