When shopping at the supermarket, many people have bought crispy fruit and vegetable snacks such as onion crisps and mushroom crisps. Many people think that the crispy texture is achieved through a one-step frying process, but in fact, after frying, there will still be a certain amount of free water residue in the material, which is easy to soften after being stored for a long time and leaves an opportunity for microorganisms to take advantage of. This is also the reason why many crispy snacks need to be moisture-proof and have strict shelf life control.
In actual production, some fried crisps are not packaged directly after frying. At this point, the penetrating heating characteristics of microwaves can be utilized as a post-treatment process.
Ordinary hot air drying mostly transfers heat from the surface of the material to the inside, which can easily lead to the situation where the surface has already dried hard and the internal moisture has not yet come out. Microwaves can penetrate into the interior of the crisps, causing the water molecules in the ingredients to vibrate synchronously and generate heat, allowing water to escape evenly from the inside out. This process is not about "frying again", but about gently further removing residual moisture.
After the moisture content decreases, on the one hand, the internal structure of the crisps becomes drier and less likely to absorb moisture and soften, resulting in a more pronounced and long-lasting crispy sensation when bitten; On the other hand, the decrease in water activity, coupled with the certain bactericidal effect attached to the microwave process, can reduce the possibility of bacterial and fungal growth, and improve the safety and stability of food without adding excessive preservatives.
Of course, this process requires more precise process parameters. If handled excessively, it is easy to dry and burn the crispy chips, and even cause them to become bitter; If not handled properly, the ideal drying effect cannot be achieved. In actual production, it is necessary to adjust the processing intensity and time based on the thickness, oil content, and initial moisture of the chips, in order to find a balance between being "sufficiently dry" and "not excessively heated".
Simply put, microwave is more like an internal assisted drying method here: it does not change the basic flavor imparted by frying, but uniformly removes residual moisture inside, while optimizing taste and improving safety. It is an optional post-processing approach for crispy fruits and vegetables, as well as some fried snacks.
QQ