Primary Investigation into the Occurrence of Hydroxymethylfurfural (HMF) in a Range of Smoked Products

Abstract

5-Hydroxymethylfurfural (HMF) is produced in foods through many different pathways. Recently, studies have revealed its potential mutagenic and carcinogenic properties. Determination of HMF was originally used as an indicator of both the extent of thermal processing a food had undergone and food quality. It has been identified in a variety of food products such as bread, breakfast cereals, fruit juices, milk, and honey. In addition to the thermal processes that lead to the formation of HMF during thermal treatment, food smoking also creates conditions that result in the formation of HMF. This can take place within the food due to the elevated temperatures associated with hot smoking or by the proximity of the products of the pyrolysis of the wood matrix that is used for smoking (cold smoking). This may lead to further contamination of the product by HMF over and above that associated with the rest of the preparation process. Until now, there have been no studies examining the relation between the smoking procedure and HMF contamination in smoked food. This study is a primary investigation measuring HMF levels in three categories of smoked food products, cheese, processed meat, and fish, using HPLC-UV. The amount of HMF found in all three product categories supports our hypothesis that HMF levels are due to both internal pathways during processing and external contamination from the smoke generation matrix (wood) employed. The results ranged from 1 ppb (metsovone traditional Greek smoked cheese) to 4 ppm (hot-smoked ready-to-eat mackerel). Subsequently for smoked cheese products, a correlation was found between HMF and phenolic compounds generated by the smoking procedures and identified by SPME-GCMS. It was observed that cheese samples that had higher concentrations of HMF were also found to have higher concentrations of syringol and cresols. It is important therefore to understand the smoking procedure’s effect on HMF formation. This will aid in the development of mitigation strategies to reduce HMF formation while retaining the flavour of the smoked products.