Eating healthy has its science, there is no doubt about it. A good example is when we make use of our willpower to increase our fruit intake and doubts arise such as: is it just as healthy to eat fresh fruit as a dehydrated one? Luis Robles Ozuna, an academic from the Center for Research in Food and Development (CIAD) helps us answer this question.
The application of thermal treatments to food, led by heat and mass transport phenomena, as is the case of fruit dehydration, causes great changes in texture, appearance, color, flavor, and nutritional value. The most common changes are non-enzymatic browning, protein denaturation, and thermal destruction of heat-sensitive vitamins and pigments. It has been reported, for example, a reduction of 6% in vitamin A in apples, 55% in thiamine in apricots, up to 10% in niacin in peaches, and up to 56% in vitamin C in plums.
But, not everything is bad news, since, through the dehydration of fruits there is an increase in the concentration of fiber. However, all this depends on the way the dehydration process is carried out, and even the adverse effects can be reduced with the use of appropriate techniques and processes, such as the adoption of new technologies that can allow lower processing times, mainly.
The sugar dilemma
The drying of fruits and foods is an ancient and widely used technique for preserving these products. Dehydration is used to eliminate water (up to 3-10%) and thus reduce the deterioration reactions inherent to each food. Currently, the demand for quality dried or dehydrated products is constantly increasing around the world, since they have a long shelf life and the packaging requirements are minimal.
One drawback, if you want to look at it that way, is that during the dehydration of fresh fruits, the phenomenon of sugar concentration is imminent and, generally, these solutes dissolved in the water of the food are transported and redistributed in the different components of the fruit. In this sense, sugars can concentrate in greater quantities on the surface of the fruit due to entrainment during evaporation.
A minimum solids concentration of 200% is usually present and up to 350 or 400% about the original or fresh fruit has been reported, and this depends on the fruit, size, shape, and drying method. For this reason, considering that dehydrated fruits increase their concentration of solutes by up to three times their original content, it would not be appropriate to be consumed by people who are watching their sugar intake.
From the point of view of the types of sugars contained in dehydrated fruits, some authors state that they have the same composition as fresh fruits, only with less water, and that the glycemic index of sugars is low or medium, so their consumption does not imply any problem, except for the amount of dried fruit eaten.
An obligatory comparison
It is important to point out that the world food market refers to dried fruits as "ingredients", so their final consumption should be that, although, of course, this is not a limitation for people to eat them directly as a snack or collation. However, the detail is that dried fruits are much more energetically dense than fresh ones; that is, they contain more calories. In the case of dried apples, for example, 100g of this product would provide six times more calories than the same portion in the fresh product, and in the case of peaches, it would be four times more.
Buying fresh fruit in bulk is a challenge to mentally calculate calories, but when it comes to packaged products, the nutritional labeling that is currently established by law helps us to know from the moment of purchase the amount of food we can consume. On the other hand, the use of food composition tables can help us in a more generic way to calculate the portion we want to consume, since it is difficult to consider a factor, in general, by which to multiply and obtain a real result of the caloric intake of each fruit.
How to distinguish when substances are added to dried fruit?
Nowadays, the sensory perception of food products is a very important marketing issue. In the case of dried fruits, their natural appearance is opaque and their flavor is very similar to the characteristic taste of the fruit from which they come. For this reason, some current techniques based on the final use of the food, employ different additives to make them more attractive to consumers and apply sorbitol to give a moist and soft appearance. It is even common to use glucose and fructose to have the same effect in different products. In other cases, the use of sucrose or glucose powder causes a different color to the originally dehydrated fruit.
The natural texture of dehydrated fruits is crunchy, so when sugar or any other additive is added to them, it is done to have a different texture, generally softer, which directly impacts the color and brightness of the product. In this context, in packaged products, the addition of these substances must be visible on the packaging or label.