From field to freezer
Most commercially produced fruit and vegetables are frozen immediately after harvest when nutrient concentrations are at their highest. This is very important as concentrations of some vitamins can decrease by 50 percent within the first 7 days after harvest when stored at normal temperatures.
Preparing vegetables for freezing
In preparation for freezing, vegetables must first be blanched (heated for a short time in hot water or steam). This can result in the loss of some water-soluble and heat liable vitamins and minerals. However, losses from the conventional boiling of raw vegetables in the home can be greater as the time needed for cooking is longer. Research has shown that the vitamin C content in cooked frozen peas is comparable with raw peas that have been stored and then cooked.
People often mistakingly believe that only fresh fruits and vegetables are of benefit and that processed produce does not provide the same levels of nutrients, due to losses during the processing procedures. In actual fact, some methods of food processing, such as freezing, can actually help preserve levels of nutrients in the food, as the nutrient concentrations are placed in 'suspended animation' whilst the product remains frozen.
How freezing affects nutrients
The affect that food processing has on a nutrient depends on its physical properties. Some are fairly resistant to changes in temperature, light and atmosphere. Others, however, such as vitamin C and folate are extremely susceptible to changes in conditions and initial concentrations can rapidly decrease depending on how the produce is treated. Scientific studies have shown that vitamin C levels in some vegetables are actually lower in the fresh form that have been distributed and stored at ambient or chilled temperatures than in those that have been immediately frozen after harvest. Other studies have shown that vegetables stored at room temperature over 2-3 days may lose 50-70 percent of their folate content.
Frozen food provides a quick and easy way of helping people to improve their diets. It doesn’t require any chopping or peeling which suits today’s busy mums, it can often be prepared within minutes, and its excellent nutritional benefits, all combine to make frozen food the perfect solution.