Saudi Arabian researchers fight grain waste with water-repellent jute bag

20 Oct 2021 --- Researchers in Saudi Arabia have pioneered a simple surface treatment for traditional jute storage bags, preventing moisture-induced damage to stored grains.

The King Abdullah University of Science and Technology (KAUST) team was inspired by water-repellent surfaces found in nature.

Each year, up to one-third of harvested grains are lost due to environmental factors like moisture, fungi and pests, the researchers note. In developing countries, cereal grains, such as wheat, rice and maize, are staple foods. However, on a calorific basis, their losses can be as high as 60% due to moisture damage.

The strong, hardwearing jute bags underpinning traditional grain storage, particularly in rural and developing regions, have a significant limitation – they absorb and retain moisture. The storage infrastructure in places of high humidity or rainfall can be inadequate in preventing moisture from seeping into these bags.

“Farmers put extraordinary time, energy and resources into growing crops,” says Kennedy Odokonyero, a postdoctoral researcher working on the project. “But when a 1% rise in seed moisture content can exponentially reduce seeds’ shelf life by up to 50%, it is easy to see how rapidly a whole crop can be lost. This [loss] is not just a devastating waste of food, it also dampens the morale of those who worked so hard to produce it.”

“From an ecological and practical perspective, improving an extensively utilized biodegradable material like jute is ideal,” adds Odokonyero’s project partner, Himanshu Mishra.KAUST researchers develop a grain storage solution preventing moisture-induced damage while improving seed germination efficiency.

Toughening up jute
Jute is a plant-based product composed of “water-loving” components like cellulose. The researchers treated jute with an alkali to roughen its surface and alter its surface properties. They then added a very thin layer of paraffin (candle) wax to the bags before testing their water repellency under simulated rain and relative humidity ranging from 55-98%.

The grain storage experiments, which lasted two months, revealed that seed moisture content was reduced by up to 7.5% in wax-coated bags. Moreover, the seed germination efficacy after storage was up to 35% higher than in seeds stored in ordinary jute bags.

Grains stored in the wax-coated bags experienced far fewer fungal infections, regardless of relative humidity. “Longer trials are needed to examine the efficacy and durability of the bags,” acknowledges Odokonyero.

Second life uses
The wax-coated bags are reusable but could also create an organic mulch once they are no longer fit for storage purposes. The mulch could reduce evaporation in farmers’ fields and add nutritional content to the soils.

“With further comprehensive trials, we hope to refine and optimize this wax-coating technique, with the hope that one day it can be rolled out at scale,” concludes Mishra.

Edited by Joshua Poole