Indian scientists have been making news with their research in all the fields and as UPSC gives more importance to current affairs; knowledge of advancements in the field of science and technology will help the IAS aspirants score better.
Nanotechnology-based applications of hexanal for agriculture
Bananas, mangoes and papayas: these tender tropical fruits are in high demand in export markets and an important livelihood source for producers. But freshness is key because these fruits spoil quickly and damage easily. The challenge is especially daunting where refrigeration is lacking. Estimates suggest that up to 40 per cent of produce in tropical countries is lost in post-harvest handling.
Breakthrough research by Canadian, Indian and Sri Lankan partners points to a promising innovation: nanotech applications of a natural plant extract called hexanal can be used to delay fruit ripening. Hexanal inhibits a plant enzyme that is responsible for breaking cell membranes during a fruit’s ripening process.
In initial research in India and Sri Lanka, scientists used a hexanal-impregnated formula to test the product on mangoes. Spraying orchards with a low concentration of the compound slowed fruit ripening by three weeks. The team is also developing “smart packaging” systems, made from materials such as banana fibre, that slowly release hexanal to extend storage life after fruit is harvested.
These applications can boost farmers’ incomes. “Let’s say a mango farmer sprays half or one third of the orchard with the formulation,” explains Jay Subramanian, a professor at Canada’s University of Guelph. “He gets that same mango production but spread out over a three- to four-week window instead of just one week, which causes a major rush and a glut in the market, leading to low prices.” In field trials, farmers were able to earn up to 15% more for their crop. Once harvested, the sprayed mangoes remained fresh for up to 26 days in cold storage and 17 days at room temperature.
Researchers at the University of Guelph, India’s Tamil Nadu Agricultural University and Sri Lanka’s Industrial Technology Institute are building on this early success. Under a second phase of funding through the Canadian International Food Security Research Fund, a joint initiative of Canada’s International Development Research Centre and Global Affairs Canada, they are taking their investigations beyond Asia.
Together with institutions in Kenya, Tanzania, and Trinidad and Tobago, they are looking at hexanal applications with other fruits under different growing conditions. The research teams are testing a variety of sprays, coatings and packaging on bananas, citrus, papayas and even some Canadian tender fruits and berries. Each fruit presents its own unique challenges, such as ripening along different timelines, requiring fine-tuning of the application process.
Biosafety testing shows promise. Already approved as a food additive in the United States, hexanal leaves no harmful residues. “It’s a very natural compound,” says Dr Subramanian. “In our academic research we have found that if you spray or dip the fruit with it, within 48 hours it’s all gone; you can’t find even a trace using a microscope.”
A range of new materials is being developed, including wraps containing electro-spun or sprayed nanoparticles infused with hexanal for slow release of hexanalvapours. While exploring ways to delay ripening and improve shelf life, scientists are looking for opportunities to commercialise these technologies so they can be scaled up. The aim is to ensure the technology has a global reach and benefits low-income farmers, not just large producers.
Non-Polluting nano fertiliser
Indian-origin researchers in the US have shown that zinc nanoparticles can substitute nitrogen and phosphorous fertilisers to increase plant growth without causing water pollution – a serious problem with conventional fertilisers.
A nanoparticle is an ultrafine object that behaves as a whole unit in terms of its properties.Fertilisers, which provide nutrients needed for plant growth, are traditionally applied to the soil either by spreading them on fields or mixing them with irrigation water. Excess nitrogen and phosphorus, unused by the plants, eventually get washed into rivers and lakes – polluting the water.
Research scientist Ramesh Raliya and Pratim Biswas, chairman of the Department of Chemical Engineering at the Washington University in St Louis , reported that zinc nanoparticles may provide a better approach to fertilise the plants. They said their experiments on mung bean (also known as green gram) plants show this approach is environment friendly and can potentially reduce the use of conventional fertilisers.
“Currently, farmers are using nearly 85 per cent of the world’s total mined phosphorus as fertiliser. At this rate, the world’s supply of phosphorus could run out within the next 80 years,” the scientists reported in the Nanowerk Nanotechnology News online journal. “Use of zinc nanoparticles can help conserve natural mineral reserves and energy and reduce water contamination. It also can enhance the plants’ nutritional values.”
In their experiments, the scientists used zinc nanoparticles synthesized in their laboratory on mung bean plants. The plants grew larger with 27 per cent increase in biomass and produced six percent more beans than plants that were grown using typical farm practices but no fertiliser. Mung beans are a high source of protein, fibre and antioxidants and the plants are widely grown for food in Asia.
According to the report, zinc nano-fertiliser is environment friendly as it can be directly sprayed on to the plant leaves without coming into contact with soil. Since the particles are extremely small, plants absorb them more efficiently than via soil. In their experiments, they sprayed the zinc nanoparticles through a customized nozzle directly on the leaves of mung bean plants.
Nano fertiliser also has the potential to increase plants’ nutritional value, the scientists reported. In a separate study they found that applying titanium dioxide and zinc oxide nanoparticles to tomato plants increased the content of “lycopene” – an antioxidant in the tomatoes – by 80 to 113 per cent. “Making plants more nutrition-rich in this way could help to reduce malnutrition.”
In contrast to conventional fertiliser use, which involves many tonnes of inputs, nanotechnology focusses on small quantities. “These particles have unique physical, chemical and structural features, which we can fine-tune through engineering,” the researchers said, adding that they chose zinc nanoparticle for their studies since zinc is “a micro-nutrient that plants need to grow, but in far smaller quantities than phosphorus.”
The researchers, however, cautioned that before nanofertilizers can be used on farms, “we will need further studies to understand how nanoparticles behave within the human body and regulations to ensure they will be used safely.”