I have been thinking about this for a long time. After discussing this matter with my nutritionist friends and my dietician, I came to know a lot of things. Definitely I would like to share them with you.
We all have the natural tendency to assume that fresh vegetables and fruits score high so far as nutrition is concerned. But you would be surprised (or shocked?) to know that this assumption is a false one. In comparison to their unprocessed counterparts, frozen vegetables and fruits can offer more nutrition.
Now, you would definitely want to know why? Well, I have the answer to this. To explain this matter, we need to talk about the commercial freezing process.
A look at the commercial freezing procedure
Before freezing, vegetables are blanched which means that for some time, they are immersed in boiling water. The process of blanching aims to make the naturally occurring enzymes inactive so that the vegetables do not deteriorate.
Usually fruits are not subjected to the blanching process. After washing, they are directly frozen owing to their high acid content and delicate texture. The acids preserve the fruits when they are frozen by slowing down the process of deterioration.
Modern technology is used to freeze the fruits and vegetables quickly. This does not allow the formation of big ice crystals, which have the potential to damage the cell walls. The rapid freezing process enables the food to keep its color, texture and flavor intact to the maximum extent possible.
Comparing the nutritional content
The impact of processing and storage on frozen vegetables and fruits has been a matter of constant research. Here are some of the findings based on the nutritional content.
- Vitamin C: When vegetables are freshly picked, they contain most of the Vitamin C. However, degradation of this vitamin starts occurring immediately following harvest. Since the vegetable is water-soluble and heat-sensitive, a certain amount is lost when vegetables are blanched. The complete freezing process may make vegetables lose as much as 50% of this vitamin. But as one of my nutritionist friends told me, we must not think that fresh ones are better. Processed frozen vegetables stored for a year may lose 30% of vitamin C whereas fresh vegetables lose as much as 75% of the vitamin within four days.
- B vitamins: Folate, riboflavin, thiamin, and other B vitamins are also water-soluble and heat-sensitive. Hence, they also show similar results like vitamin C. After the initial loss during blanching, Vitamin B remains stable in the frozen vegetables, and as is expected, the content is higher compared to that of fresh ones.
- Antioxidants: To speak technically, these are in fact phenolic compounds which undergo a natural oxidation process in fresh vegetables due to the enzymes present. Once heat treatment inactivates the enzymes, the antioxidant content of frozen vegetables is preserved. So far as fruits are concerned, frozen raspberries and blueberries are seen to contain more antioxidants than their fresh counterparts.
- Vitamin A: Vitamin A is not too much sensitive to heat or blanching procedure. Hence in frozen fruits and vegetables, the level remains the same compared to fresh ones.
If you want to use frozen fruits and vegetables, do not allow them to thaw after taking them out of the freezer. Directly put them into the preparing dish.