Calcium in oranges
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Calcium in Oranges: Bioavailability, Fortification, and Nutritional Impact
Calcium Bioavailability in Oranges
Oranges are a significant source of calcium, and their bioavailability is enhanced when consumed in certain forms. Studies have shown that calcium absorption from calcium citrate malate (CCM) fortified orange juice is notably high. For instance, calcium retention from CCM in orange juice was 42.8%, significantly higher than the 33.0% retention from water. This indicates that orange juice can effectively deliver bioavailable calcium, making it a valuable dietary source.
Fortification and Calcium Absorption
Fortifying orange juice with calcium has been shown to be effective in increasing calcium intake. A study comparing calcium absorption from fortified orange juice and milk found no significant difference in bioavailability between the two, with both showing similar absorption rates. This suggests that calcium-fortified orange juice can be an excellent alternative to dairy products for those looking to increase their calcium intake.
Impact of Calcium on Orange Quality
Calcium not only benefits human health but also plays a crucial role in the quality of oranges. Spraying calcium nitrate (Ca(NO3)2) on Newhall navel orange trees during the fruit drop period significantly improved fruit quality. This treatment increased the calcium concentration in leaves and reduced the fruit drop rate, leading to a higher yield and better fruit quality. Additionally, active calcium treatments have been shown to increase the fresh weight, soluble carbohydrate content, and total sugar content of navel oranges, further enhancing their quality.
Calcium and Mineral Content in Citrus Fruits
The mineral content of citrus fruits, including oranges, varies between the peel and the pulp. Oranges are particularly rich in calcium, potassium, phosphorus, and manganese, making them a valuable source of these essential minerals. The bioaccessibility of calcium in orange residues is also significant, with cooking methods influencing the mineral's bioavailability. For example, cooking increased the dialyzable fraction of calcium in orange residues, making it more accessible for absorption.
Erosive Potential of Calcium-Fortified Orange Juice
While calcium fortification in orange juice is beneficial for increasing calcium intake, it also affects the juice's erosive potential. Adding calcium to orange juice has been shown to reduce its erosive potential on dental enamel. A study found that calcium-modified orange juice had the lowest percentage of surface microhardness change, indicating it was the least erosive compared to other modified juices. This suggests that calcium fortification not only enhances nutritional value but also mitigates potential dental erosion.
Conclusion
Oranges are a rich source of calcium, and their bioavailability is significantly enhanced when consumed as fortified juice. Calcium fortification in orange juice provides a viable alternative to dairy products for increasing calcium intake. Additionally, calcium treatments improve the quality and yield of oranges, making them more nutritious and appealing. The mineral content in oranges, particularly calcium, contributes to their overall nutritional value, and fortification strategies can further enhance their health benefits while reducing potential dental erosion.
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