THE SCIENCE OF PASTA SALAD

There's nothing I love more on a balmy evening than tucking into a bowl of cold penne mixed with a variety of crisp veggies and herbs. Drape it all in a tangy dressing and it's the ultimate summer comfort food.

- Jennifer Pallian

Making pasta salad may seem effortless, but there's science involved in nailing the best texture and flavour. Ever notice how day-old cold pasta has more bite? That's because cooling cooked pasta causes starch retrogradation, which changes its molecular structure and its absorption properties, as well as how it behaves in dressing and in your body.

As pasta cooks, starch granules absorb some of the hot water and swell. This is called gelatinization.

The outer layer of the pasta turns tacky due to the gelatinized starch on the surface.

As the pasta cools, gelatinized starch begins to recrystallize and harden. This changes the pasta's texture, making it less soft and sticky, which in turn causes the pasta to absorb less dressing. This means the salad stays moist but not soggy. Retrogradation also turns some of the starch into resistant starch; this acts like dietary fibre, which can be beneficial for gut health. It also lowers the glycemic index of the pasta, so you'll have less of a blood-sugar spike after eating it.

Cooling pasta by rinsing it under cold water stops the cooking process and brings the temperature down quickly. This method is convenient but doesn't allow for much starch retrogradation. Cooling pasta in the fridge for a longer period allows for more extensive realignment of the starch molecules.

It will have a chewier texture and won't slurp up all the dressing or break from tossing.

The bottom line: pasta refrigerated overnight is better for your pasta salad (and perhaps for your body). However, you should still cool the pasta quickly in cold water first to halt the cooking process so that it stays al dente. Here are three recipes to test out this technique.

Thai Peanut Pasta Salad