It doesn’t come as a surprise when it is known that a freezer is one of the best appliances to preserve and store food. From tenderizing meat to retaining the freshness of fruit and even solidifying the fats contained in red meat, making it easier to cut through; interestingly it also comes with other possible uses that might have been unfamiliar before. Many traditional food practices around the world have sought to freezing food by packing it under layers of snow and even in “icehouses” before artificial refrigeration became the norm. So effective were these techniques that food would remain fresh for months on end, and go on to be consumed in the warmer months of the year. Here is how freezing specific kinds of food affects their flavour and texture, through a scientific lens.
For Starch
Image Credits: Leite's Culinaria
The idea of a fluffy, warm and delicious root vegetable like sweet potato or regular, starchy potato being baked and loaded with all the fixings is delicious in itself. While a major part of ensuring to get the texture of these starchy tubers makes a difference to the taste – in a way that the vegetable does not overcook and dry out – freezing comes in handy to produce the most beautiful baked or roasted output. Since these vegetables contain a fair amount of moisture within, freezing potatoes, turnips or beetroot before sticking them into the oven converts this moisture into ice crystals which develop jagged edges to puncture the cells within the flesh. Hence, when these starchy vegetables are roasted frozen, a natural enzyme called amalyse develops as it thaws and reaches an internal temperature between 57-76 degrees Celsius. The enzyme converts the starch into sugars, resulting in the tubers developing a hint of sweetness that is enhanced in savoury dishes.
For Fruit
Image Credits: McCormick For Chefs
One of the ancient practices to freeze food in China was to repeatedly freeze fruit until the outer skin turned dark and the fruit inside was bursting with juices. More recently, the technique of cryo-macerating or ice poaching fruit involves repeatedly freezing and thawing hard fruit like pears or peaches, in order to allow the slow-developing ice crystals (similar to the ones that form in starchy vegetables) to break open cell walls of the fruit. What this does is retain the freshness of the fruit, make it tender enough to bite into and produce more juices than what the fruit formerly had. What makes the skin of such fruit darken is the oxidisation due to damage but remains intact until cut into. Such freezing applications work well even for fruits like tangerines, apples, plums, apricots and cherries.
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For Tofu/Soft Cheese
In the case of freezing tofu, similar crystallisation process like for fruit and starchy vegetables continues to take place; only this time, the ice crystals tenderize the coagulated proteins in tofu or paneer. When this happens and the paneer thaws, the water content in these products drain out, leaving them with porous air pockets that absorb any savoury sauces or liquids that they are added to. You can also enhance the effect and enable the absorption of more flavour by gently squeezing out the moisture and coaxing more liquid out of your tofu or paneer.