Effect of Solar Drying Process on Bioactive Compounds and Antioxidant Activity in Vitro of High Andean Region Bee Pollen

Abstract

Bee pollen is a hive product of common consumption with a known and remarkable content of bioactive and functional compounds, namely carotenoids and phenolic compounds. The bee pollen from the Colombian High Andean region has a prominent content of these compounds due to environmental and botanical conditions. In this work, the process of bee pollen drying by solar dehydration was evaluated to determine its influence on functional compounds and antioxidant activity. This process was carried out in a greenhouse type solar system located in the central region of Colombia into the High Andean region. Drying tests were conducted for two consecutive days during the dry season. The tests were developed for 8h, collecting samples at the beginning (t = 0h) and at the end (t = 8h) of the process. The contents of total carotenoids, total phenol compounds and antioxidant activity in vitro of samples were measured by spectrophotometric standard methods: a spectrophotometric measure of acetone extract for carotenoids, Folin-Ciocalteau for phenol compounds and TEAC/FRAP for antioxidant activity. The content of carotenoids in dry bee pollen was in average 0.9mg s-carotene/g. Besides, the content of phenolic compounds of bee pollen processed in the solar system was 16mg gallic acid/g. The content of carotenoids and phenol compounds in dry bee pollen did not change significantly from initial raw bee pollen. Furthermore, the antioxidant activity of raw bee pollen (0.85mmol Trolox/g) was maintained even after the drying process in the solar dehydration system. The results show that there was no impact of the solar drying process on bioactive compounds content of bee pollen. Therefore, this type of solar drying system is an actual alternative to traditional equipment for bee pollen drying at this region, favoring a lower energy cost and with a no evident influence on the product quality.