Effects of storage temperature and juice pulp on the content of bioactive compounds and antioxidant activity of pomelo

Antioxidants are known for their health benefits, capable of neutralizing free radicals in the body, preventing several chronic diseases and reducing oxidative stress. Through this research work we were interested in comparing the contents of bioactive substances and evaluating the antioxidant activity of the juice according to its conservation method at two different temperatures (4 and -20°C) and the influence of the presence or absence of the juice pulp. We have selected three cultivars of pomelo cultivated at INRA-Kenitra: pomelo ‘Thompson’, pomelo ‘Star Ruby’ and pomelo ‘Marsh’. The extraction and quantification of flavonoids and total phenolic compounds was carried out according to the aluminum trichloride (AlCl₃) and Foling-Ciocalteu methods, respectively. The method applied to measure antioxidant activity was free radical scavenging using DPPH (2,2-diphenyl-1-picrylhydrazyl). Our results indicated that the juice containing pulp has a high antioxidant property compared to the juice without pulp. The effect of freezing the juice decreases its titratable acidity and °Brix, but freezing the juice preserves a large amount of flavonoids and phenolic compounds with minimal difference in the three accessions studied.