Ethylene tested as sprout inhibitor in storage potatoes CU LTIVATION AND TECHNOLOGY placed in the air flow above the potatoes, the generator ensures that the level of ethylene automatically remains at the desired low and safe level during the entire storage season. ‘A generator has the capacity to keep a maximum of 6,000 tons of potatoes free of sprouts. On delivery, you can process the potatoes from the storehouse immediately, you don’t have to wait. This provides flexibility in the planning of the potato processing factory where, with other products, you sometimes have to wait fourteen to thirty days’, says Garos. ‘Ethylene gas leaves no residue, it’s an authorised organic product and is also used in baby food, where the highest food safety requirements apply’, he adds. Sprout inhibition with ethylene gas continues to act for another three days in the receptors of the potato. ‘The advantage of this is that fresh and/or cold air can be ventilated in the storehouse every night without disturbing the dormancy. This also helps if you’ve forgotten to refill the ethanol, or if there’s a brief generator breakdown during the storage process’, says Garos. The baking test results ‘Over the past ten years, we’ve carried out trials in various countries and gained practical experience in collaboration with R&D companies, research stations and multinationals’, Garos explains the experience the company has acquired. The results show that ethylene doesn’t work equally well for every variety. For example, in a variety such as Bintje, the benefits of its use have not been demonstrated. In the coming years, the company will therefore focus on three specific potato varieties for the European continent for which ethylene, according to the company, does produce good results: Fontane, Marqués and VR808. This brings us to the baking test that follows the presentation. From each of the three varieties mentioned above, twenty French fries are cut from a batch preserved with CIPC and a batch preserved with ethylene. They are fried for three minutes at 180 degrees, while the specialists from the industry watch In the storehouse, the Restrain Generator safely produces pure ethylene gas by converting ethanol (alcohol) using a calalyst. the process. For Garos and his colleague, technical manager for Europe Paul O’ Connor, it’s particularly exciting, partly because the growing conditions in 2018 were really extreme. The results of the potatoes from cell 5, stored with CIPC, are slightly-coloured, as desired. But how are ‘their own’ potatoes, stored with ethylene from cell 6, doing? If we look at the Fontane, for example, the French fries are slightly, but evenly, darker over their entire length. ‘A bit of discolouration is not a problem, the most important thing is that it’s even, because you can always control this with blanching before the baking process,‘ says NAO field staff member Maries Elemans. Cost price comparable to CIPC For sprouts that may already have developed on the potato before they are stored, ethylene has a blocking effect on the lengthwise growth of the sprout. The thickening at the ends of the already-emerged sprouts show the ‘ethylene effect’. ‘When CIPC disappears, we’ll need an alternative. We’ve opted for an afFordable price per ton of treated industrial potatoes. The cost of using ethylene for storage is comparable to that of CIPC. Depending on the amount of ethanol you use, the cost is around 3.50 euros per ton, including the ethanol. For example, if you take 1,000 tons of potatoes – where you normally carry out three applications of CIPC – the cost of storage when using ethylene is approximately the same. It’s difficult to say exactly what the ethanol usage is, so it could be cheaper for one user and more expensive for another. The greater the volume, the cheaper it gets. Moreover, the user needn’t invest in the generator, because we supply one under an operating lease. Furthermore, you don’t need any changes to the storehouse. We’re going for exponential growth and aiming at the large masses, with a focus on three varieties’, he concludes decisively. ● Zindziwe Janse Potato World 2019 • number 3 41 Pagina 40

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