Cry-free onions developed via crossbreeding introduced to UK market

By Flora Southey

- Last updated on GMT

BASF has succeeded in developing a more homogenous strain of onion with desirable characteristics: less pungency and more sweetness. GettyImages/SolStock
BASF has succeeded in developing a more homogenous strain of onion with desirable characteristics: less pungency and more sweetness. GettyImages/SolStock

Related tags Onion crossbreeding

A variety of sweet onion that doesn’t reduce the cook to tears has secured a listing at Waitrose & Partners. US-headquartered BASF is behind the innovation.

The idea for the ‘tearless’ onion is around 35-years in the making, when back in the 80s BASF plant breeder Rick Watson decided he wanted to develop a mild, sweet onion that wouldn’t reduce the cook to tears.

Branded Sunions, the product has been on the US market for four years. Now, the same seeds are crossing the pond where they are grown in Spain for UK consumers.

Crying over spilt…onion cells

When an onion is cut, its cells release lachrymator compounds into the air that irritate the nerves around the eyes. This can result in free-flowing tears in the kitchen.

While some may well wonder what’s the fuss about a bit of extra salt in a dish, others are keen to farewell blurry eyed knife work during food prep.

The innovation started in the US. More than three decades ago, researchers started looking for onion strains with less pungency, since this is what irritates the eyes and causes tears.

Natural plant crossbreeding involves crossing one strain with desirable characteristics (such as less pungency), with another (with sweeter characteristics). Or else you can ‘breed it to itself’ by self-pollinating it. Over time, this helps to develop a more homogenous strain of onion.

crying onions IgorTsarev
When onions are cut, their cells release compounds that irritate the nerves around the eyes. GettyImages/IgorTsarev

BASF has described the development – which it stresses does not rely on genetic modification – as a ‘breakthrough’ in onion genetics. Overall, the company has spent 24 years and $5m in incremental investment to develop and breed Sunions.

Sweet success

The other defining aspect of BASF’s development is its ‘sweet flavour’. The company claims to be the first to introduce a storage onion that has the combination of ‘tearlessness’ and sweetness.

Further, the onion changes flavour over its storage time: becoming milder and sweeter in flavour.

Other storage onions, on the other hand, become hotter while stored – which reduces their sweetness levels. In conventional storage onions, pyruvates (the chemical compound in biochemistry relating to glucose) can increase from 5-6 to as much as 5. In Sunions, pyruvate levels fall from 5-6 to 3 or less during storage.

“Sunions become sweeter and more tearless when stored, unlike other onions where the opposite happens, they become more pungent over time,” ​a BASF spokesperson told FoodNavigator.

“Therefore, Sunions need to be maintained in storage for a certain time to ensure their favourable characteristics.”

Sunions are also particularly ‘crunchy’, noted BASF, making them suitable for salads or in fresh applications, as well as in cooked meals such as stuffing.

sunions Waitrose
Sunions are launching into Waitrose stores this month. Image source: Waitrose & Partners

The world’s first tearless and sweet onion variety is rolling out across Waitrose stores from the 18th​ of this month.

“We understand how a-peeling tearless onions are to our customers which is why we’re delighted to launch Sunions in selected stores… Ideal for taking the tears out of the kitchen, the sweetness of this type of onion lends itself perfectly to a variety of dishes, from salads to hot meals,” ​said Paul Bidwell, onion buyer at Waitrose.

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