Edible coating Liquidseal keeps fruit fresh longer

Liquidseal from Leiden developed an edible coating that makes fruits and vegetables last longer. This protective coating is already on the market for avocados and mangoes. The coating reduces food waste and the use of packaging materials. Experts in preservation are enthusiastic, as long as food safety is not compromised.

Of the food produced annually worldwide, one-third is lost, totaling some 1.3 billion tons. Some of this spoils between harvest and consumption. To combat this, the company Liquidseal from Leiden in the province of Zuid-Holland has developed an edible coating. This keeps fruit and vegetables fresh up to twice as long and also reduces the use of environmentally harmful packaging.

General manager Victor Monster explains that vegetables and fruit continue to 'breathe' after harvesting and that the coating slows this process down. Liquidseal uses plant-based components that also protect the product from drying out.

Liquidseal was founded in 2005 by four people from the same street in Oegstgeest. They came up with a liquid to extend the shelf life of flower bulbs. After years of experimentation, the initiators exhibited their lily bulb coating at a trade fair. There they came into contact with rose importers who were struggling with botrytis infections during the transport of the flowers.

The company came up with a protective coating that extends the shelf life of roses in 2011. That product generated enough revenue to enable research into a coating for fruits and vegetables. The initial focus was on hard-shelled fruits: avocados, citrus, mangoes and papayas. Liquidseal entered the market in 2018 with the first fruit coatings, which are applied to the product by dipping or spraying.

Less weight loss

Tests by the Institute for Innovation and Development in Agrifood in Michoacan, Mexico, showed that the coating not only improves the shelf life of mangoes and avocados, but also prevents weight loss. The agent further ensures that the sugar content and color are preserved. Since the beginning of this year, Total Exotics in Bleiswijk has been importing avocados and mangos with a Liquidseal coating from South America for Scandinavian and Belgian supermarket chains.

According to Monster, the innovative coating is in line with the agreements from the European Green Deal to reduce the amount of packaging material and to combat food waste. A sustainable packaging must above all be functional and protect fruit and vegetables from deterioration and damage, adds Jenneke Heising. She is conducting research at Wageningen University & Research into intelligent packaging that monitors food quality. She is positive about coating as a solution to combat spoilage.

An important criterion, she says, is that the layer on a product must be biodegradable and safe. She sees the addition of antimicrobial agents and antioxidants as a valuable addition to the product. There are enough natural and safe variants of these, such as citric acid and extracts from mustard seed, broccoli and essential oils.

Heising also advocates additional packaging that can monitor the quality of fruit and vegetables, for example by measuring temperature, humidity and the production of ethylene and microorganisms. But only if the disadvantages of such additional packaging outweigh the reduced food waste. In increasing sustainability you always have to look at the effects throughout the chain.'

Sustainability ladder

The Knowledge Institute for Sustainable Packaging (KIDV) is also watching the rise of fruit and vegetable sealing with interest. 'In making packaging more sustainable, it is important that it does not cause food waste or litter and is easily recyclable or reusable,' says packaging expert Marcel Keuenhof. Alternatives that make packaging superfluous, such as coatings, of course also score high on the sustainability ladder.'

In the legislation and regulations in the European Union on food safety of packaging, attention is paid, among other things, to the migration of substances into food, such as mineral oils from the ink used for printing. KIDV will soon publish a series of fact sheets, including on issues such as mineral oils and heavy metals in packaging.

'Migration is only allowed if it poses no risk to health and that will also apply to coatings,' Keuenhof says. In addition to food safety, he mentions the effect of the interaction between the packaging material or the coating on the taste or color of the product.

Liquidity will be affected by the use of the coating.

Liquidseal is in the process of developing its coating recipe for pineapples and bananas and has already done tests on apples, pears and plums. The same is true for cucumbers, onions, tomatoes and peppers. 'A coating on those products is allowed in the United States, for example, but unfortunately not yet in Europe,' says Monster. 'We're in talks with Brussels about that.'

Source: new-harvest