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Healthy ingredients are easier to absorb from the juice than from the fruit
The healthy ingredients of oranges can be absorbed much better when consuming orange juice than when eating the whole fruit, according to a recent study at the University of Hohenheim. The researchers explicitly disagree with the opinion of some critics who consider orange juice to be unhealthy due to its high sugar content.
Oranges offer a high content of health-promoting nutrients. In addition to a high concentration of vitamin C, they have a variety of carotenoids and flavonoids that can lower the risk of certain cancer or cardiovascular diseases, ”reports the research team led by doctoral student Julian Aschoff and study leader Professor Dr. Dr. Reinhold Carle, Chair of Technology and Analytics of Plant Food at the University of Hohenheim. In their current study, they investigated what is actually healthier - the whole fruit or the orange juice.
Criticism of orange juice due to high sugar content Recently, the reputation of orange juice has suffered significantly due to the relatively high natural sugar content, since for many nutritionists sugar in food is a fundamental evil, according to the Hohenheim University. Often, instead of squeezed orange juice, people are advised to eat oranges. In England, a "penalty tax" was even proposed for all fruit juices and orange juices were banned from some kindergartens as "junk food", the university reports. The current study has now clearly refuted these reservations about orange juice. In fact, the nutrients from the juice are potentially better absorbed by the body than from the fruit itself, explains study leader Professor Carle. The carotenoid and vitamin C levels in juice production would be slightly reduced, but at the same time "the release of these ingredients and thus the amount that the body can absorb and utilize increase many times over."
In vitro model simulates digestive processes To check the nutrient intake when eating oranges or orange juice, the researchers use an in vitro model that simulates the digestive process of the human body. This model of the human digestive tract forms a standard procedure for determining the release of nutrients from food, which is common worldwide, according to Aschoff. In the test tube, the same conditions were created one after the other as they exist in the mouth, stomach and small intestine during the digestion of oranges and orange juice. "In addition to mimicking the human chewing effect to shred the fruit, the scientists also added saliva, digestive enzymes and bile, modeled the movements of the food in the gastrointestinal tract and performed the tests at body temperature," the university said Hohenheim. All processes have only been carried out in the dark so that light-sensitive ingredients are preserved, Aschoff reports.
Pasteurized juice better than freshly squeezed For the study, the researchers produced juice from one of the most popular types of orange - the Navel orange - and in addition to freshly squeezed juice and ordinary direct juice, they also produced a flash-pasteurized juice. The latter is often sold chilled as "premium juice" in supermarkets, said Aschoff. "We then compared the release of the nutrients from these three juices with that from the fruit," continues the food technologist. The researchers found that "the release of carotenoids, which play an important role as provitamin-A in the human body, increased from 11 percent in the fruit to over 28 percent in fresh juice and up to 40 percent in pasteurized juice". The carotenoids from the juice are potentially four times more bioavailable than from the fruit.
Orange juice overall is the better source of nutrients "If you take the results from our publication, orange juice is the better source of carotenoids than the fruit itself," reports Aschoff. The ingredients in the juice would be released better when pasteurized than when the whole fruit was consumed and could thus be better absorbed and metabolized by the body. The results of the current model tests would also be confirmed by a recently completed human study, Aschoff continued. According to the researchers, orange juice - as long as it is consumed in moderation - is healthy and recommended, regardless of whether fresh juice, direct juice or juice from concentrate is preferred. "Since fruit and vegetable consumption in Germany is far below the recommendations of the German Nutrition Society, the consumption of orange juice can contribute to a healthy diet," explains Professor Carle.
Avoiding orange nectar better However, according to the researchers, orange nectar is an exception. The experts at the University of Hohenheim strongly advise against this. The term nectar initially sounds good and suggests that it is a particularly high-quality product as the “potion of the gods”. "In reality, half of the nectar is mixed with water and then fortified with sugar to make it as sweet as a juice," says Professor Carle. In the end, the orange nectar contains as much sugar as an orange juice, but only has half the vitamins. In terms of a healthy diet, the experts therefore generally recommend avoiding orange, apple and pineapple nectar. Nectars would only be justified if 100% juices were not edible as such due to the high acidity of the fruit, such as sour cherries and currants, or because of their viscosity (e.g. bananas and apricots). (fp)
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