In June, researchers from the University of Florida published a new study in the journal Food Chemistry Advances. The study revealed that storing blood oranges in a colder environment after harvest can enhance their already impressive health benefits.
To reach this conclusion, the researchers tested various storage temperatures for blood oranges harvested at commercial maturity. After transporting the fruit to the University of Florida's post-harvest lab, where they were inspected for defects and sanitized, the oranges were placed on a bench for drying. The team then divided them into four groups and stored them for 60 days at temperatures of 6, 8, 10, or 12 °C, maintaining a humidity level of 90%.
The study discovered that these temperatures can "markedly influence anthocyanin accumulation, phytochemical content, and antioxidant activity," highlighting that "lower storage temperatures around 6–8°C proved most beneficial in maintaining certain physicochemical characteristics."
The study noted that anthocyanins, which are plant pigments responsible for deep red, purple, and blue hues, have demonstrated benefits such as lowering blood pressure, reducing the risk of heart disease, and potentially slowing cancer growth. Therefore, preserving higher levels of anthocyanins in the blood oranges would be desirable.
Phytochemicals, as described by UCLA Health, constitute the plant's natural defense mechanism against viruses, bacteria, fungi, and parasites. They also provide similar protective benefits to humans, shielding cells from harm induced by environmental toxins and the body's intrinsic chemical reactions.
In the study's findings, researchers also observed that the fruit exhibits a slightly higher sugar content when stored at cooler temperature, along with a more intense coloration. However, they noted that this effect is "least noticeable" under the coldest storage conditions.
"The team concluded that these discoveries offer valuable insights into using carefully controlled temperatures after harvesting as a straightforward, natural strategy to boost anthocyanin pigmentation and other health-enhancing properties in blood oranges grown in tropical and subtropical climates, where such accumulation is not typically favored before harvest."
However, according to a statement from the researchers regarding their findings, anthocyanin development occurs when "the fruit is subjected to cold temperatures ranging from 46 to 59 degrees for at least 20 days," conditions that are "uncommon in Florida's subtropical climate." Despite this, the team emphasized that this enhancement in nutritional profile resulting from a modified storage approach presents a "promising opportunity" for citrus farmers in Florida."
The researchers noted that this approach could ultimately help to promote blood orange products that are both healthier and more visually appealing, aligning with market demand and consumer preferences." The implication being that consumers would be drawn to blood oranges with enhanced nutritional and aesthetic qualities.