In which of the following is soy often a hidden ingredient?

Soy is often a hidden ingredient in pasta because many commercial pasta products may use soy flour or soy protein as a filler or added nutritional content. This inclusion can occur without being prominently listed, especially in processed or specialty pasta varieties aimed at increasing protein content. Consumers may not be aware that these soy derivatives are often blended with traditional wheat flour, thus making them a less obvious source of soy for those avoiding it for dietary or allergy reasons.

In contrast, while soy can also be found in burgers, pizzas, and cooking oils, the presence of soy in these items is more commonly recognized. For instance, soy sauces or soy-derived products may be more explicitly noted in burger seasoning blends or pizza toppings. Cooking oils might contain soy as an oil blend, but that is often labeled clearly on product packaging. As such, pasta stands out for the potential of soy to be incorporated more subtly into the ingredient list, making it an important consideration for those monitoring their soy intake.