Formation and relevance of 5-hydroxymethylfurfural in bioactive subcritical water extracts from olive leaves

• Published in: Food research international Vol. 47; no. 1; pp. 31 - 37
• Main Authors: Herrero, M., Castro-Puyana, M., Rocamora-Reverte, L., Ferragut, J.A., Cifuentes, A., Ibáñez, E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.2012; Elsevier
• Subjects: 5-hydroxymethylfurfural; Antioxidant; antioxidant activity; Antiproliferative; Biological and medical sciences; colorectal neoplasms; Food engineering; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; HMF; hydroxymethylfurfural; leaves; liquid chromatography; Maillard reaction; mass spectrometry; olives; Subcritical water extraction; SWE; temperature; HMF; SWE; Antiproliferative; 5-hydroxymethylfurfural; Maillard reaction; Antioxidant; Subcritical water extraction; Antineoplastic agent; Water; Heat treatment; Extract; Plant leaf; Olive; Plant part; Extraction
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2012.01.008

Although subcritical water extraction (SWE) has already shown its great potential for the attainment of natural bioactive extracts, concerns still remain on possible unexpected reactions that can arise during the extraction process, usually taking place at high pressure and temperature. It is already well-known that different components might be formed during the SWE extraction protocol due e.g. to Maillard reaction, which can improve the bioactivity of the obtained extracts. On the other hand, the formation of other compounds derived from these reactions, such as 5-hydroxymethylfurfural (HMF), has raised some concerns, mainly related to its safety. In this work, the formation of HMF during subcritical water extraction, at different conditions, from olive leaves has been monitored by using liquid chromatography with mass spectrometry (LC–MS) and diode array detection (LC–DAD). The possible influence of this compound in the overall antioxidant and antiproliferative activities against colon cancer cells has been also studied. Results showed an increase of HMF formation when increasing the extraction temperature, being the maximum concentration achieved at 200°C (3.17μgHMF/mg extract); nevertheless, the HMF contained in the olive leave extracts did not influence the antioxidant capacity or the antiproliferative activity of the natural extracts, thus demonstrating the safety of the SWE process. ► Formation of HMF is increased when increasing extraction temperature in SWE. ► HMF did not show any effect on the bioactivities of the extracts. ► SWE can be regarded as a safe process to attain bioactive extracts from olive leaves.