What kind of packaged juice is the freshest squeeze? Swetha Sivakumar explains

The company uses satellite imaging to pick its oranges at just the right ripeness. Every batch of juice is measured on parameters such as sweetness, acidity, etc. The algorithm matches this analysis with its database on customer preferences and the 600-plus flavour markers that make up “orange”. Using that framework, it combines different batches just right for a consistent flavour.

All this balance and planning are essential because this product’s only ingredient is oranges. (The leftover peel is used too, oil and aromatics extracted and added to the juice for a fresh orange flavour.)

That’s quite a lot of advanced technology for a simple concept: “Squeeze fruit, get juice.” Why does store-bought juice always get so complicated? For one thing, most fruits are only in season part of the year. It takes a lot of modern technology to make orange juice possible in autumn, and grape juice all year round.

For another, as soon as a fruit is squeezed, live enzymes start the slow process of breaking down the pulp and juice; unrefrigerated, it takes mere hours for it to spoil. First the colour starts to change. Next, the fragrance degrades. Vitamin C levels drop too.

Juice companies have to slow this ticking clock as much as they can. To prevent microbial growth, most juice is either flash-pasteurised (heated to high temperatures quickly and cooled quickly thereafter) or concentrated (boiling off excess water). It is then stored in de-aeration tanks to keep it from oxidising. These steps can extinguish a lot of the fresh flavour compounds, so some companies add artificial flavours such as ethyl butyrate, and artificial colours just before packaging.

So when you’re out shopping, first look at the front of the box for juices. If the word “juice” is on the pack, you can proceed to step two. This step involves checking for added sugar. Companies have to account for variations in fruit flavour between farms, between harvests. The easiest and most cost-effective way to do this is to add sugar and acids to round out differences in taste.

To avoid added sugars, buy packs that say “100% juice”. This means the product does not have any ingredient that diminishes the amount of juice-soluble solids. (Small amounts of natural or artificial flavours, artificial sweeteners, vitamins and preservatives are allowed).

If you wish to buy a juice without preservatives, look for a Tetra Pak. This invention from Sweden, popular since the 1960s, avoids preservatives through a process called aseptic packaging. The juice box is literally built around the juice as it is filled up, in a sanitised environment. This ensures that the juice stays almost entirely microbe-free until it is opened. (It may still contain other additives such as sweeteners or stabilisers, so watch out for those.)

Another brilliant technology that preserves juices without added preservatives is high-pressure processing (HPP, also called Pascalization, after the 17th-century French scientist Blaise Pascal, who laid the groundwork for it). These are the juices labelled “Raw” or “Cold Pressed”. This process does not use heat to kill microbes. Instead, it uses intense levels of pressure — much, much more pressure, in fact, than in the depths of an ocean.

Satellite imagery, algorithms, heat, cold, pressure… something to think about the next time you open the fridge to take an innocuous bottle or pack out on a hot summer day.