How’d we do that?

So how’d we “make” nonbrowning Arctic® apples? This modern marriage of nature and science is simpler than you may think.

So how’d we “make” nonbrowning Arctic Apples?Browning 101

Enzymatic browning is the primary type of apple browning. It is caused by the apple’s chemical reaction after cell injury, such as by bruising, biting or cutting the apple. Enzymatic browning is a predominant cause of apple browning due to handling, for example in your kitchen. Arctic apples don’t undergo enzymatic browning. (Let any food get old enough, such as leaving it in the fridge too long, and any apple – including Arctic apples – will eventually suffer other types of browning.)

Meet the PPO gene family

When you bruise, bite, slice or dice an apple, rupturing the apple cells’ walls, a chemical reaction is triggered between the apple’s polyphenol oxidase (PPO) and phenolics that turns the apple flesh brown. And unfortunately, that reaction burns up the apple's health-promoting phenolics in the process. Read more here. A family of four genes controls the majority of PPO production.

Apple-to-apple transformation

To scientifically breed Arctic apples, Okanagan Specialty Fruits’ science team turns down the expression of the apple PPO genes in a process called gene silencing, which utilizes low-PPO genes from other apples. Gene silencing is a natural process that all plants (and animals too) use to control expression of their genes. This apple-to-apple transformation is aided by time-proven biotechnology tools. In the end, Arctic apples produce too little PPO to brown. (For an even more detailed description of Arctic apple science, visit the OSF website.)

No frankenfood here, folks – just apples, now with suppressed PPO to stop enzymatic browning.

The transformed Arctic apple plantlets are grafted onto rootstock and grow in a tree nursery until they are ready to be transplanted to an orchard, just as other commercial apple tree seedlings are propagated.*

One small, significant difference

Arctic apple trees behave in the orchard just as other apple trees do – they grow, flower and fruit the same way, and react to pests and weather the same way. And Arctic fruits grow, are harvested, packed, stored and shipped just as other apples are.

In other words, Arctic apple trees and fruits are identical to their conventional counterparts in every way – until you bite, cut or bruise the fruit, that is. That’s when the handiwork of their silenced PPO genes becomes evident. No PPO, no browning. No enzymatic browning, no “yuck” factor to discourage you from enjoying that delicious apple.

Related content:

*Did you know? Apple trees aren’t grown from seeds – they are “grown” by grafting bud wood from a tree of the desired variety onto a selected rootstock.