The formation of a toxic substance when high fructose corn syrup is heated raises concerns for bee keepers, say researchers, and will help inform advice on safe storage of the ingredient for use in human food.
High fructose corn syrup (HFCS) is a sweetener commonly used in food products. HFCS 42, containing 42 per cent fructose, is mostly used in bakery and confectionery products, which HFCS 55 (a mixture of HFCS 42 and 90) is commonly used in soft drinks.
It is also used in bee keeping to stimulate brood rearing in the spring and to increase honey production. Bees’ predilection for the sweetener was first observed when they were seen to swarm to spillages of the syrup around facilities and rail roads.
However the researcher from the USDA report in a new study that the heating of HFCS raises levels of hydroxymethylfurfural (HMF), a toxin that causes gut ulceration and dysentery-like symptoms in bees. In humans it has been linked to DNA damage, and its daughter metabolites levulinic and formic acids have also been seen to cause harm.
"The data are important for commercial beekeepers, for manufacturers of HFCS, and for purposes of food storage. Because HFCS is incorporated as a sweetener in many processed foods, the data from this study are important for human health as well,” they wrote in the Journal of Agriculture and Food Chemistry.
The researcher from the USDA reached their conclusion after measuring HMF levels in samples of HFCS over a 35 day time frame, at temperatures of 31.5, 40.0, 49.0 and 68.8ºc.
They saw that HMF levels increased steadily with temperature, and that there was a dramatic jump at 49 ºc. The chemical forms as the fructose dehydrates, with mineral and organic acids acting as catalysts.
The tests were conducted using five different commercial samples of HFCS 55 donated by Roquette, Mann Lake, Archer Daniels Midland and Tate & Lyle.
The researchers say that the data in their report should allow commercial users of HFCS to estimate the concentrations of HMF formed with time and temperature.
When it came to storing the material, the team found that conditions are crucial. At the outset HFCS 55 in a 203.5 litre drum had a level of 18 ppm HMF; within a year this had risen to 57 ppm at ambient, uncontrolled temperature.
The Codex Alimentarius Commission has a HMF limit of 40 ppm for honey sold for human consumption.
One way of limiting the formation of the chemical could be to neutralise the HFCS with inexpensive bases like lime, potash and soda ash then treating it with antifermenting agents – a logical approach since HCM formation is catalysed by acid.
However they added: “Although neutralising HFCS with commercial bases effectively reduces HMF, microbiological growth will become much more problematic, although these bases may be toxic to microbes.”
Journal of Agriculture and Food Science 2009, 57, 736907376
Formation of hydroxymethylfurfural in domestic high fructose corn syrup and its toxicity to the honey bee (Apis mellifera)
Authors: LeBlanc, B; Eggleston, G; Sammataro, D; Cornett, C; Dufault, R; Deeby, T; St Cyr, E.