Fresh or Frozen Ingredients – Which is Best?
Various ingredients are available in either fresh or frozen form. Does it make a difference?
For freshly picked fruits and vegetables, the organoleptic properties, taste, smell and appearance would certainly be expected to be better than for frozen.
However, as time progresses after picking, the quality of frozen items might well be better than rapidly deteriorating fresh produce, which start to break down their own nutrients and oxidise due to being separated from their source of nutrients and energy in the ground or from a tree. The rate of deterioration of particular nutrients and the oxidisation process – when the fruit or vegetable turns brown for example, e.g. after cutting open an apple – varies in different types of produce.
By comparison, with frozen produce the oxidisation process is paused immediately at the point the produce is frozen, usually after it’s been picked at its peak ripeness (and thus its peak nutritional value). The freezing process can happen within just a few hours of being picked and processed, whereas the harvesting, processing, storing and transportation of fresh produce can be up to 12 months prior to being available to the consumer! Even though the storage conditions are controlled, this obviously affects how ‘fresh’ the fresh produce really is at the point of being used. Sourcing locally grown fresh produce and using it soon after it’s been picked can therefore make a difference to its nutrient quality.
So, from a nutrition point of view, there may be subtle differences between fresh and frozen. On the day of freezing, there should be no difference. For the unfrozen product however, the quantity of some vitamins may decay significantly in storage. For example, in studies the deterioration of vitamin C, which is particularly sensitive to oxygen and light, has been shown to be significantly slower in frozen compared to fresh fruit. Vitamins in frozen products can decay, but it does take a long time.
However, in the case of vegetables some micronutrient content (water-soluble nutrients, such as vitamin C and B-vitamins) is reduced when blanched, (heated up in boiling water for a few minutes) prior to being frozen. Blanching is done in order to inactivate unwanted enzymes that can degrade both texture and colour during frozen storage so this is a trade off.
When products are defrosted prior to being cooked, they may gain water through condensation on the cold surface and whilst this does not affect the total nutrient content of the batch, the dilution will reduce the ‘per 100g’ values to some extent.
The rate of freezing produce can also impact the formation of ice crystals that can damage the structure of food, for example creating sogginess in vegetables. Freezing at a faster rate can create smaller ice crystals, which leads to a better texture and eating experience.
Microbiologically, the quality of frozen products would be expected to be superior to fresh products after a period of time had elapsed, because bacteria, yeasts and moulds would tend to grow on fresh products. There is also some anecdotal evidence that freezing may kill off small quantities of pathogenic organisms.
It would seem then that, due to the time delay between harvesting fresh produce and getting it to food producers, unless local or home grown produce is consumed, there is often little or no benefit to using fresh over frozen produce.
Several research studies have found that there were no significant differences in macronutrient profiles of frozen and fresh vegetables, and if there was a slight difference, it was more likely that the frozen vegetables had a higher concentration of micronutrients than their fresh counterparts.
Aside from their nutrient quality, there can be a notable price premium for using fresh rather than frozen produce, and of course there’s a consideration regarding a lack of availability of certain fresh produce when it’s out of season.
There is also the question of whether the produce has been farmed organically or using pesticides, which can affect the micronutrient quality.
Using fruit & vegetables in your recipes, may mean that it counts towards your 5 a day even if there isn’t enough of any single one to constitute a portion under the UK Five-a-Day healthy eating initiative, because you can add them together, often with excellent results.
NutriCalc’s nutrition calculation software calculates Five-a-Day portion sizes for fruits and vegetables, juices and concentrates (Premium Plan subscribers).
Five-a-Day claims may also give a very useful commercial advantage. Some foods can give impressive results, such as a vegetable soup with a good portion size.
From the point of view of selecting ingredients in NutriCalc, our experience is that using information for a fresh fruit or vegetable can be used when using a frozen one (or vice versa). This is because the difference in nutrition values between fresh and frozen will normally be no greater than natural variation between different varieties or seasonal variations.