Feeding a growing planet: respiration and ripening

Much of the food that the world produces is never eaten. With a rapidly growing world population, the issue of food waste will be increasingly important over the 21st century. There are many factors that will play a role in cutting down food waste, but understanding the biological processes within the key crops that feed us is vital.

“Much of the food that the world produces is never eaten.”

Keeping the crop safe - farmers in Kenya using improved storage methods to control post-harvest losses.

Keeping the crop safe – farmers in Kenya using improved storage methods to control post-harvest losses.

A report from the Institute of Mechanical Engineers states that

“Today, we produce about four billion metric tonnes of food per annum. Yet due to poor practices in harvesting, storage and transportation, as well as market and consumer wastage, it is estimated that 30–50% (or 1.2–2 billion tonnes) of all food produced never reaches a human stomach. Furthermore, this figure does not reflect the fact that large amounts of land, energy, fertilisers and water have also been lost in the production of foodstuffs which simply end up as waste. This level of wastage is a tragedy that cannot continue if we are to succeed in the challenge of sustainably meeting our future food demands.”

“This level of wastage is a tragedy that cannot continue if we are to succeed in the challenge of sustainably meeting our future food demands.”

But what role does understanding respiration play in reducing food waste?

Fresh fruits and vegetables continue to respire for a short period after harvest. Respiration involves the breakdown of carbohydrate stores into energy, releasing carbon dioxide and water. The length of time that fruit and vegetables stay edible depends on their respiratory activity. By storing them at low temperatures and controlling the oxygen and carbon dioxide concentrations surrounding them, we can reduce the rate of respiration, and extend their storage life.

Farmers in Pakistan prepare their grape harvest for cold storage, helping them reach new customers.

Farmers in Pakistan prepare their grape harvest for cold storage, helping them reach new customers.

 

Find out more
  • Global Food: Waste not, want not   The Institute for Mechanical Engineers
  • How reducing food waste could ease climate change (National Geographic, Jan 22, 2015). This interview with the head of a refrigerated transport company offers a useful view on food waste from the commercial perspective.
  • Prevention of post-harvest food losses fruits, vegetables and root crops: a training manual (The Food and Agriculture Organization of the United Nations, Rome 1989). This manual, developed by the Food and Agriculture Organization of the UN, introduces the importance of the loss of fruits and vegetables after harvest, what the physiological causes are, and how losses can be reduced. Although the manual is now rather elderly, it is a useful practical introduction to the issues.
Practical Investigations – step-by-step protocols

We’ve put together step-by-step protocols for you to use for a practical investigation on this topic.

 

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