While the use of “puffing” process is mainly limited to products like cereals or carrot, the instant controlled pressure drop (DIC) can treat and expand the large domain of heat sensitive food products. In the present article, this operation is applied on partially dried apple and onion, to produce snack or, by shadow grinding, expanded granule powder. DIC is a high-steam pressure treatment (up to 0.6 MPa in this article), where steam is applied constantly during a short treatment time t (5–55 s) and instantaneously dropping the pressure toward vacuum 5 kPa with a rate higher than 0.5 MPa s⁻¹. The expanded structure allows the product to achieve better functional properties linked with a greater specific surface area. Thus, the time of final hot air drying (with air flow at 40°C, 1 m s⁻¹, and 267 Pa partially pressure humidity) is reduced by about 55% through greater effective diffusivity and initial starting accessibility. The product's nutritional value is partially preserved (vitamins) or even improved through more available flavonoids. DIC can perfectly decontaminate the products, and end quality attributes are higher than normally dried or as good as freeze-dried fruits.

In the present article, a new manner to use the instant controlled pressure drop (DIC) was adopted in the drying of onion. Instead of using it as a texturing treatment inserted in the second stage of hot air swell-drying operation and performed when water content is less than 30 g H₂O/100 g dry matter, here the DIC was performed as a blanching–steaming pretreatment of fresh cut onion, with a steam pressure of 0.2–0.5 MPa, for 5–15 s, and an instant pressure drop (with a rate > 5 MPa s⁻¹) toward a vacuum of 5 kPa. Afterward, drying was carried out with 40°C, 1 m s⁻¹, and 267 Pa partially pressure humidity hot air. Although this DIC treatment aimed to avoid notable expansion, it could intensify mass transfer, reducing the total drying time, which reached 700 min instead of 3200 min for untreated samples; the effective diffusivity and the initial starting accessibility dramatically increased. Consequently, sensorial and nutritional attributes could be preserved with a perfect decontaminated end product.