Nitrogen. Oils and fats. Oxidation. And why the bags are designed to be so puffy with inert gas.
1-Minute NomNom
Quick! If someone fell into a river, what could you do to save her?
May we recommend some bags of potato chips?
We are not joking. There is so much air in these bags that a group of Korean students built a raft out of bags of potato chips and floated down Seoul’s Han River (see video above). They felt snack companies were “ripping people off” by putting so much air in the bags, and wanted to stage a humorous protest.
But blowing up the bags of potato chips with all that air is no accident. There is in fact a good reason: they help to keep the chips fresh and crispy. And more accurately, what is inside is not air per se, but the inert gas nitrogen.
Potato chips are made by frying thin slices of cut potato in hot oil. The oil “replaces up to 80 percent of the water in the potatoes, the slice is twice as thin as it started, and the result is crisp and crunchy“. It is what makes chips so delicious (and so dangerous to those of us who love potato chips :P).
The oils and fats in the potato chips can however become rancid from oxidation. An easy way to remember what oxidation is, is to think of it as “adding… oxygen to a compound“.
Composition of air
If the bags of potato chips were filled with air – which has about 20% oxygen – the oil and fats’…
“… unsaturated components are converted into hydroperoxides, which break down into volatile aldehydes, esters, alcohols, ketones, and hydrocarbons, some of which have disagreeable odours.” (Source: Encycolopaedia Britannica)
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Which we know as food gone rancid. This is why nitrogen is used. It is not only an inert gas (i.e. chemically inactive) that does not react with the fats and oils, it is also abundant.
Besides exposure to oxygen, how fast oxidation happens also depends on other “factors such as temperature, light… and the presence of moisture“. Filling up the bags of potato chips with nitrogen reduces the amount of moisture and insulates them against rapid temperature changes. The bags are also designed to be opaque to block out ultraviolet light.
Moreover, the puffed up bags of potato chips are like bubble wrap. They protect the chips from being crushed accidentally, either from the jiggling and wobbling during transportation, or from the pokey pokey fingers of prying customers in the supermarket aisles.
Hence blowing up the bags of potato chips with the inert gas nitrogen is all about reducing oxidants and accidents, and keeping our potato chips fresh and yummy.
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