Learn the science behind:
Fresh fruits and vegeables are very perishable. It’s a lot harder to keep these well, especially in comparison to something like dried grains, breakfast cereals or sweets. Since most of us don’t want to buy fresh fruits and vegetables every day it is a matter of storing the fresh products smartly. Since not too long we have a fridge with a so-called hydrofresh drawer. It’s advertised as greatly increasing shelf life of fruits and vegetables. Honestly, I was pretty sceptic about it, but it works wonderfully well! We’re able to store just about all fresh vegetables for at least one week easily. So what’s the secret?
Respiration & Dehydration
Let’s start with the basics, how to keep fruits and vegetables fresh. In a previous post we’ve discussed the importance of respiration of fruits and vegetables. As long as they can respire they can stay good. So when storing fruits and vegetables one of the most important things is to keep them breathing.
The other important factor is loss of moisture, dehydration. Water is essential to give fruits and vegetables their firmness caused by the phenomenon called turgor. Once they have lost too much moisture products will shrinkle and dry out and lose their attractiveness.
Keeping fruits and vegetables fresh
So keeping these two phenomena in the back of our minds, what can we do? In order to keep respiration going we want to: slow it down without stopping it. As discussed in the post on modified atmosphere packaging there are packaging tricks you can use to achieve that. But when you buy your own fresh produce that is hard to do. So the remaining trick is:
- Lower temperature (but without freezing, the ice crystals will damage the cells)
To prevent dehydration you want the surroundings of the fruits and vegetables to be moist. Water travels to the area where its concentration is lowest. So placing a courgette in a very dry room will cause it to dry out a lot faster than placing it in a very moist fridge. Thus the trick is:
2. Increase the humidity of the storage area
A fridge is vital for most people to keep their food fresh and safe. Most fridges are set at 7°C, however, putting a fridge just a few degrees lower can have a huge effect on the shelf life of your products. For fresh fruits and vegetables this for sure can be a huge benefit.
HydroFresh – A magic drawer?
This low temperature solution is one of the reasons the HydroFresh drawer seems to work. The drawer has a lower temperature than the rest of the fridge. This helps to reduce the rate of respiration as well as the rate of loss of moisture.
The second trick of the drawer has to do with the moisture content in the drawer. First of all, the bottom of the HydroFresh drawer isn’t flat, instead it is curved. If there is any excess moisture in the drawer it will sit in between the curves. This prevents the fruits and vegetables from sitting in any excess moisture.
Then there another simple adjustment, the moisture content of the drawer can be regulated by a little switch at the top. The more open it is, the more moisture can evaporate out of the drawer, thus the drier it is. If there are a lot of fruits and vegetables in the drawer producing moisture through respiration it could be good to let some extra escape. But, honestly, who would think of adjusting this switch depending on the type and quantity of products in there? We certainly never do so, therefore not sure whether it’s actually working.
Not a one solution fits all
Even though this solution can be a great way to improve the shelf life of a lot of fruits and vegetables, it isn’t a ‘one size fits all’. Not all fruits and vegetables should be stored in the fridge. Some, like bananas or tomatoes, even decrease in quality when stored in the fridge. In future posts we will allude to this in more detail. For now, the solutions mentioned above work for those fruits and vegetables that can be stored in the fridge.
We would certainly invest in a Hydrofresh drawer again, we’re able to store our fruits and vegetables for considerable long periods of time. It seems as if there is some decent science and reasoning behind it as well, which is something I can appreciate!