Acrylamide in cereal and cereal products: a review on progress in level reduction.

In March 2006, a joint workshop was organized by the European Commission and the Confederation of EU Food and Drink Industries (CIAA) to discuss current knowledge and achievements in the reduction of acrylamide levels. This paper focuses on the progress made with cereal products. At present, the reduction options available are applicable to a limited number of cereal products and are product-specific. The following are the most promising: * Adjustment of time and temperature during baking. * Extend fermentation times where feasible. * Substitution of ammonium bicarbonate with alternatives where feasible. * Avoid or minimise use of reducing sugars where possible. * Maintenance of uniform control of the colour and avoidance of very high baking temperature where possible. The most promising near-term technical solution is the use of asparaginase. This enzyme has the potential to achieve a 60-90% reduction for some products made from dough or batter, which can be held for a time. In the longer term, the optimisation of agronomy and plant breeding for wheat has the potential to reduce acrylamide in all foods on any scale, whether domestic or industrial. Importantly, nutritional and toxicological issues, other than acrylamide, must also be considered so as to ensure that the steps taken to reduce acrylamide levels do not have other adverse effects on diet.

Effects of yeast stress and pH on 3-monochloropropanediol (3-MCPD)-producing reactions in model dough systems.

A major precursor of 3-monochloropropanediol (3-MCPD) in leavened cereal products is glycerol, which is formed as a natural by-product of yeast fermentation. However, yeast metabolism is affected by stresses such as low osmotic pressure from, for example, the incorporation of sugar or salt in the dough recipe. Tests with model doughs have shown that glycerol production was proportional to yeast mass and limited by available sugars, but that high levels of yeast inhibited 3-MCPD formation. The yeast fraction responsible for the inhibition of 3-MCPD in model dough was shown to be the soluble cytosol proteins, and the inhibition mechanism could be explained by the known reactions of 3-MCPD and/or its precursors with ammonia/amino acids (from yeast proteins). Added glucose did not increase the production of glycerol by yeast but it did promote the generation of 3-MCPD in cooked doughs. The latter effect was attributed to the removal of 3-MCPD inhibitors such as ammonia and amino acids by their reactions with added glucose (e.g. Maillard). The thermal generation of organic acids from added glucose also reduced the pH of cooked doughs, so the effect of pH and short-chain organic acids on 3-MCPD generation in dough was measured. There was a good correlation between initial dough pH and the level of 3-MCPD generated. The effect was weaker than that predicted by simple kinetic modelling, suggesting that the involvement of H+ and/or the organic acid was catalytic. The results showed that modifications to dough recipes involving the addition of reducing sugars and/or organic acids can have a significant impact on 3-MPCD generation in bakery products.

Occurrence of 3-chloro-propane-1,2-diol (3-MCPD) and related compounds in foods: a review.

A critical review of the occurrence of 3-chloro-propane-1,2-diol (3-MCPD) in foods not known to contain hydrolysed vegetable proteins is presented. The review covers the properties and chemistry of 3-MCPD and the current methods of analysis in foodstuffs. The results of UK surveys of 3-MCPD occurrence in both retail foods and commercial food ingredients are discussed with particular reference to cereal, meat and dairy products. The possible mechanisms for the formation and decay of 3-MCPD in foods are suggested. The review does not cover the detailed toxicology of 3-MCPD and its occurrence in hydrolysed vegetable proteins, which have been considered elsewhere, nor possible issues such as in-vivo formation.

3-Monochloropropane-1,2-diol (3-MCPD) in food ingredients from UK food producers and ingredient suppliers.

A survey of 3-monochloropropane-1,2-diol (3-MCPD) in a range of food ingredients available in the UK is reported. The survey was conducted for the Food Standards Agency to assess the progress made by manufacturers in reducing levels of 3-MCPD in food ingredients in line with the UK Food Advisory Committee's recommendation, i.e. that 3-MCPD is undetectable (i.e. < 0.010 mg kg(-1) in foods and where technologically feasible, in food ingredients as well. Sixty-three samples of food ingredients available in the UK were analysed using a validated method of analysis with a limit of quantification of 0.010 mg kg(-1). Samples included breadcrumbs, caramels, enzyme-hydrolysed vegetable proteins, gelatines, malt products (malt extracts, malt flours and other malt-based in gredients), meat extracts, modified starches, and yeast extracts. 3-MCPD was not quantified in 49 (78%) of the samples analysed. The remaining 14 samples (22%) contained levels of 3-MCPD between 0.014 and 0.488 mg kg(-1), the highest level being in a maize yellow dextrin. Malt-based ingredients accounted for the majority of samples containing 3-MCPD > 0.010 mg kg(-1), with nine of these 24 samples (38%) having quantifiable levels of 3-MCPD.

Analytical methods for the determination of 3-chloro-1,2-propandiol and 2-chloro-1,3-propandiol in hydrolysed vegetable protein, seasonings and food products using gas chromatography/ion trap tandem mass spectrometry.

The EC Scientific Committee for Foods and more recently the Food Advisory Committee in the UK have proposed that levels of 3-chloro-1,2-propanediol (3-MCPD) in foods and ingredients should be reduced to the lowest possible. This paper reports on the development of methods for the determination of parts-per-billion (microgram/kg) levels of 3-MCPD in hydrolysed vegetable protein (HVP), flour, bread, meat and starch products using gas chromatography/ion-trap tandem mass spectrometry (GC/ITMS/MS). Mass spectrometer conditions for detecting 3-MCPD and the stable isotope internal standard (3-chloro-1,2-propandiol-d7) were established. Candidate extraction methods were initially evaluated for recovery and repeatability by spiking selected commodities at a level of 100 micrograms/kg. Extracts of ingredients and foods prepared by the candidate extraction methods were examined by GC/ITMS/MS using samples spiked at a level of 25 micrograms/kg. The results showed that detection limits of between 3 and 5 micrograms/kg could be achieved for all commodities.