|Green asparagus from the fridge and from the market are not created equal - at least not when they finally end up on your plate after a short bath in hot water.|
Warning: Don't take this article as an excuse and stop eating veggies completely. The frozen stuff may lose more vitamins, when you boil it, but (a) you can still blanch it and (b) even with significantly reduced antioxidant effects veggies are still among the healthiest things you can eat.
The raw (ten kilograms of each vegetable), blanched (five kilograms of each vegetable) and industrially frozen samples (five kilograms of each vegetable) had been transported were transported to the University of Parma laboratories under adequate refrigerated conditions to avoid the exuberant nutrient loss that occurs upon inadequately slow (re-)freezing.
If you "freeze" your veggies in the freezer compartment of your fridge, this will make the cells blast, so that even before they are cooked, and the nutrients flow out. It is generally assume that the latter would not happen, if the veggies are shock-frosted.
For a similar reason (nutrient retention), the blanched samples have been cooled immediately after blanching in an ice-water bath for 3 min before they have been transported to the laboratories, where their analysis shows that only the Zucchini lost a small, but significant amount of their total antioxidant activity.
- Paciulli, Maria, et al. "Impact of the industrial freezing process on selected vegetables Part I. Structure, texture and antioxidant capacity." Food Research International (2014).