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Assessment of the stability of catechin-enriched extracts obtained from Arbutus unedo L. fruits: Kinetic mathematical modeling of pH and temperature properties on powder and solution systems

Albuquerque, Bianca R., Prieto, M.A., Barros, Lillian, Ferreira, Isabel C.F.R.
Industrial crops and products 2017 v.99 pp. 150-162
Arbutus unedo, antioxidant activity, aqueous solutions, catechin, equations, food additives, fruits, high performance liquid chromatography, hydrophilicity, industry, mathematical models, pH, prediction, shelf life, temperature
Arbutus unedo L. (strawberry-tree) fruits could be considered an alternative source of flavan-3-ols, in particular catechin and its derivatives. These compounds are known for a variety of applications in food (especially as food additives), pharmaceutical and cosmetic industry. Therefore, catechin-enriched extracts (60% flavan-3-ols and 22% of catechin) were obtained from A. unedo fruits and further submitted to physical and chemical stability studies, considering the main affecting variables (time, temperature and pH): i) a stability study of the extracts during the obtaining and storage procedures (powder system); and ii) a stability study of the extracts in simulated food environment (aqueous solution system). The measured responses were the flavan-3-ols and catechin contents, determined by High performance liquid chromatography couple to a diode array detector (HPLC-DAD), and the antioxidant activity of the extracts evaluated by hydrophilic assays. Mechanistic and phenomenological equations were used to describe the responses, and the optimal conditions for flavan-3-ols (including catechin) stability as powder extract during a month were pH=5.4 and T=−20°C; while its stability in aqueous solution remained during the 24h of application at pH <4 and T<30°C. These results provide useful information for: i) potential industrial use of A. unedo fruits as alternative sources of flavan-3-ols; and ii) shelf-life calculations and catechin loss predictions at specific conditions of temperature and pH. Finally, the results obtained showed a certain agreement with previous reports of catechin stability studies in powder and solution systems, but providing a new alternative source: A. unedo fruits.