Acrylamide

Acrylamide is a known neurotoxin[1][2] and carcinogen[3], present in heated foods (eg bread)and cigarette smoke. Acrylamide induces hepatic ornithine decarboxylase (ODC)[4] and affects behaviour by influencing hepatic mechanisms or central dopaminergic function.[5]

Acrylamide is industrially produced for various purposes (eg polymeres). Environmentally, it may be the result of decomposition of polyacrylamide (in herbicides). Acrylamide decomposes in the presence of acids, bases and oxidizing agents, rendering ammonia or nitrogen oxides. Endogenously, acrylamide is metabolized to glycidamide (an expoxide).

Acrylamide in food

Amides are derivates of ammonia or (carboxylated) amines. Particularly in hetead plant foods, acrylamide may be yielded by the reaction of amino acids (eg asparagine) and carbonyls (including amides, or yielded by sucrose decomposition or lipid oxidation) or reducing sugars (sugars yielding aldehydes; such as glucose as in starches, and other aldoses, as well as ketoses and fructose)[6]. Lower levels of reducing sugars results in lower levels of acrylamide in fried potato.[7] Particularly deep-frying has great consequences, evoking various complex reactions such as oxidation, hydrolysis, isomerization, and polymerization.[8] Some antioxidants (vitamin E) decrease the level of acrylamide produced during food processing.[9] Soybean-containing commercial bakery products contain higher levels of acrylamide than similar bakery products without soy.[10]

• Levels of reducing sugar in potatoes vary per season[11], as storing below 10°C increases breakdown of starch to sucrose, ultimately cleaved by acid invertase to produce glucose and fructose[12]. Even though potato crisps contain at least 10 fold more acrylamide (250 to 6700 mcg/kg) than acrolein (26 mcg/kg), 4 to 12 fold more acrolein- than acrylamide-related mercapturic acids are excreted in urine, which may indicate undetected varieties of acrolein.[13]
• Baking temperature and surface color correspond with acrylamide concentration in cookies. Steam-assisted baking results in lower levels.[14] Cookies baked at 150°C  for 25  minutes yielded 75 mcg/kg acrylamide, compared to 236 mcg/kg in cookies baked at 240°C  for 9 minutes.[15]
• In a Californian study, non-cancer benchmarks for acrylamide were exceeded by >95% of preschool-age children, most of the acrylamide coming from chips, cereal, crackers, and other processed carbohydrate foods.[16]
• Acrylamide crosses the human placenta. Maternal dietary exposure to acrylamide is associated with reduced birth weight and head circumference.[17]

Acrylamide food additives

• AF-2 or furylfuramide; 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (widely used in Japan[18]), was first demonstrated to be mutagenic in Escherichia coli WP-2 and then proved to be carcinogenic in experimental animals [19][20][21] 5-nitro-2-furyl is a radical.
• 5-NFAA; 3-(5-nitro-2-furyl)acrylic acid proved to be more mutagenic than AF-2.[22]

Acetamide in food

Amides are derivates of ammonia or (carboxylated) amines. Acetamide is a carcinogenic derived from acetic acid, by dehydrating ammonium acetate[23], or by hydrolysis of acetonitrile[24]. Thermal degradation (>200°C) of chitin also yields acetamide.[25] Chitin is a good inducer for defense mechanisms in plants[26], and present in fungi, the exoskeletons of crustaceans such as crabs, lobsters and shrimps, in mollusks, and in the internal shells of squid and octopus. Acetamide is also a byproduct of thermochemical treatment of lignocellulosic biomass.[27]