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Acrylamide concentrations in processed foods sold in Japanese markets were analyzed by LC-MS/MS and GC-MS methods. Most potato chips and whole potato-based fried snacks showed acrylamide concentration higher than 1000 µg/kg. The concentrations in non-whole potato based Japanese snacks, including rice crackers and candied sweet potatoes, were less than 350 µg/kg. Those in instant precooked noodles were less than 100 µg/kg with only one exception. The effect of storage condition of potato tubers on acrylamide concentration in potato chips after frying was also investigated. Sugar content in the tubers increased during cold storage, and the acrylamide concentration increased accordingly. The concentrations of asparagine and other amino acids, however, did not change during the cold storage. High correlations were observed between the acrylamide content in the chips and glucose and fructose contents in the tubers. This fact indicated that the limiting factor for acrylamide formation in potato chips is reducing sugar, not asparagine content in the tubers. Effects of roasting time and temperature on acrylamide concentration in roasted green tea are also described.

Many bakery products sold in the UK such as crumpets, batch bread and Naan might be expected to show high levels of acrylamide because they have strong Maillard colours and flavours. However, analysis of commercial products has shown that the highest levels of acrylamide are seen in dry biscuit type products. With the exception of spiced products such as ginger cake, moist high sugar products (e.g. cakes and fruit loaves) show relatively low levels of acrylamide, even in darkly browned crusts. This is in contrast to bread where acrylamide levels in excess of 100 µg/kg are common in the crust region, but are diluted by low levels in the crumb. Acrylamide levels in bread are significantly raised by domestic toasting, but other products such as crumpets and Naan bread have been found to be less sensitive. A mathematical model has been developed (and validated against tests on model dough) which shows that once obvious recipe differences are allowed for, the key factor limiting acrylamide levels is crust moisture. Chemical decay of acrylamide and depletion of amino acids are also limiting factors at higher temperatures.

The influence of ingredients, additives, and process conditions on the acrylamide formation in gingerbread was investigated. The sources for reducing sugars and free asparagine were identified and the effect of different baking agents on the acrylamide formation was evaluated. Ammonium hydrogencarbonate strongly enhanced the acrylamide formation, but its N-atom was not incorporated into acrylamide, nor did acrylic acid form acrylamide in gingerbread. Acrylamide concentration and browning intensity increased both with baking time and correlated with each other. The use of sodium hydrogencarbonate as baking agent reduced the acrylamide concentration by more than 60%. Free asparagine was a limiting factor for acrylamide formation, but the acrylamide content could also be lowered by replacing reducing sugars with sucrose or by adding moderate amounts of organic acids. A significant reduction of the acrylamide content in gingerbread can be achieved by using sodium hydrogencarbonate as baking agent, minimizing free asparagine, and avoiding prolonged baking.

Acrylamide is formed in high-carbohydrate foods during high temperature processes such as frying, baking, roasting and extrusion. Although acrylamide is known to form during industrial processing of food, high levels of the chemical have been found in home-cooked foods, mainly potato- and grain-based products. This chapter will focus on the effects of cooking conditions (e.g. time/temperature) on acrylamide formation in consumer-prepared foods, the use of surface color (browning) as an indicator of acrylamide levels in some foods, and methods for reducing acrylamide levels in home-prepared foods. As with commercially processed foods, acrylamide levels in home-prepared foods tend to increase with cooking time and temperature. In experiments conducted at the NCFST, we found that acrylamide levels in cooked food depended greatly on the cooking conditions and the degree of “doneness”, as measured by the level of surface browning. For example, French fries fried at 150–190°C for up to 10 min had acrylamide levels of 55 to 2130 µg/kg (wet weight), with the highest levels in the most processed (highest frying times/temperatures) and the most highly browned fries. Similarly, more acrylamide was formed in “dark” toasted bread slices (43.7–610.7 µg/kg wet weight), than “light” (8.27–217.5 µg/kg) or “medium” 10.9–213.7 µg/kg) toasted slices. Analysis of the surface color by colorimetry indicated that some components of surface color (“a” and “L” values) correlated highly with acrylamide levels. This indicates that the degree of surface browning could be used as an indicator of acrylamide formation during cooking. Soaking raw potato slices in water before frying was effective at reducing acrylamide levels in French fries. Additional studies are needed to develop practical methods for reducing acrylamide formation in home-prepared foods without changing the acceptability of these foods.