"First, let's look at the physical properties of apples. No matter how you slice it, every apple turns brown eventually. "When their flesh is cut, the oxygen in the air interacts with chemicals in the flesh of the apple," says Susan Brown, a plant scientist at Cornell University. An enzyme called polyphenol oxidase, or PPO, makes melanin, an iron-containing compound that gives apple cells a brown tinge. The same type of "oxidative" browning happens in the browning of tea, coffee or mushrooms, explains Brown. Within five minutes of slicing, browning can alter the taste and might not be as aesthetically pleasing, but it doesn't mean the apple is old or rotten. To prevent oxidative browning, the GM apples developed by Okanagan stop PPO production with a man-made gene containing pieces of four natural PPO genes. An insertion with gene fragments is an automatic red flag for the apple cell — usually the first step of viral attack — so it chops up every sequence of DNA that looks like the suspicious fragment, and the apple flesh stays light. "The beauty of this [process] is it's a natural plant defense mechanism," says Carter. Even when sliced, these apples stay clear of browning for about two weeks — that's roughly the same extended life span as apple slices from McDonald's and Burger King, which use lemon juice and calcium ascorbate to prevent browning. But if the apple doesn't go brown, then how do you tell if it's rotten? An apple with just oxidative browning isn't automatically rotten. Rotting comes from a fungal or bacterial infection, which causes the apple to go either mushy or dry. Infecting spores, not melanin, also give the flesh a dark brown hue. So, taking PPO out of the equation won't make a rotten apple appear pristine. "'Bad' apples will still be evident," says Brown. Rotting GM apples look rotten and turn brown from a bacterial or fungal infection the same as a conventional apple. But Bill Freese, a science policy analyst at the Center for Food Safety, notes that some studies in tomatoes have shown that silencing PPO has an impact on a plant's susceptibility to diseases and invasive insects because the enzyme may play a role in plant defense reactions."
Food industry has already known that during apple processing browning is a problem and it also has the technology to prevent or retard browning by arresting the enzymatic reaction involving polyphenol oxidase which is exposed to the air when cell integrity is affected during peeling, slicing, crushing etc. If so what is the necessity for tinkering with the genes to knock out this enzyme through biotechnology? How many consumers want the apple to be without developing brown color during the time of eating? Probably not many. Though the safety authorities in the US may accord approval for this new version of apple, it is doubtful whether these apples will be readily accepted in other countries. The new variety developed through the GMO route may have a doubtful commercial success within the US itself if consumer comes to know that it is genetically tinkered with! It is another matter that GM products are not required to be labeled in a country like the US and therefore consumers may patronize the product unknowingly.V.H.POTTY