Don expresses worry over losses on tomato post-harvest

A university don, Professor Goke Bodunde, has expressed worry over high rate of losses of harvested tomato fruits considering its current scarcity and low production process in Nigeria.

Bodunde, a Professor of Horticulture, at the Federal University of Agriculture, Abeokuta (FUNNAB), said the country was doing poorly in the processing and production of tomatoes, putting the average yield of tomato worldwide at about 25 tonnes.

He said that the average yield of tomato in the country is about 12 to 13 tonnes which is below half of the world tonnes.

He said tomato is classfied among fruits that are vulnerable to spoilage within the shortest period of time.

He explained that the poor production and processes of the fruit prompted him to embark on research that would result in increased yield of the crop and improved post harvest handling of the fruit.

“After looking at the Agronomy practices in tomato, we felt it should not just stop there. So, we decided to look at what happens after the production, which is called post-harvest handling, with reference to increasing the shelf-life of the harvested fruits. We are currently looking at the means of remediation of ethylene gas effect on stored tomato fruit, trying to minimise the effect in order to increase the shelf-life.

“Ours is not a country where we have modern storage technology, particularly, at large scale level and as such, we want to see what is attainable and can be done in our circumstance. In a situation where even if you have your cold storage device, you cannot do cold storage on account of inadequate power supply. So, we looked at those things that can be done outside cold storage.

“We looked at the use of certain chemical substances that do not necessarily have to be in contact with the fruit so that the fear of eating chemical by the consumer is allayed. What is done is that the chemical substance are used in the medium of storage and by this, I mean within a space in the environment of where the fruits are stored,” he added.

Professor Bodunde said he was able to discover a chemical substance, potassium permangnate through literature information, as a substance available in chemistry laboratories and are capable of slowing down the rate of ripening of the fruit, through absorbing ethylene gas produced by ripening fruits.

“Ethylene is a gas that triggers ripening in a fruit and has been described as auto-catalytic, causing the production of more of itself in a ripening fruit, resulting in a rapid ripening and deterioration process. So, we tried to see how we could in a way slow down this action of ethylene in tomato-storage medium by controlling or limiting its activity, as the sole substance that is responsible for the rapid deterioration of the fruit.

“We discovered that regardless of the concentration that was tested, it was efficient in absorbing the ethylene gas thereby reducing the rate of ripening of the tomato fruit, an indirect way of saying it extended the shelf-life or the length of time the fruit can stay in good quality pending consumption.

“We also discovered that as compared to seven days shelf life when the tomato is in a medium without that substance, it was able to stay 41 days in a medium with potassium permanganate solution, meaning that ordinarily, without cold storage or any special storage facility, if potassium permanganate solution is placed in the medium of storage, you can still keep your tomato for a few weeks pending utilisation.

“We are currently trying a combination of the chemical substances that we found good to see whether there would be an improvement over the 41 days that we have already established. This we have anchored on a PhD programme of a student in the Department of Horticulture and that project is ongoing. In another one to two years, we might have a better story to tell,” the Professor said.