Seasonal Variation in Nutritional and Chemical Profiles of Wild Opuntia ficus-indica Fruits

Opuntia, a cactus known for its edible fruit, produces both summer and winter fruit with distinct nutritional profiles. This study, using samples from the same plant in Northeast Portugal, revealed that winter seeds contain 2.4 times more fructose and 1.8 times more total sugars than summer seeds. Winter samples also showed a 2.3-fold increase in alpha-tocopherol content (11.69 mg/kg vs. 5.17 mg/kg in summer) and higher moisture (seed moisture: 54.96% vs. 49.52%). The peel consistently displayed the highest antioxidant activity, with summer samples generally having stronger antioxidant status. Interestingly, no statistical significance was found for the antioxidant activity or bioactive in the seed, both remaining constant between seasons. The fatty acid composition remained largely consistent, with linoleic acid as the dominant component (57-59%), though winter oil showed slightly higher saturation. Nutritional content was higher in winter samples, while bioactive constituents were more abundant in summer, and fatty acid composition remained stable across both seasons. These results emphasize the impact of seasonality on the nutritional and bioactive properties of Opuntia fruits.