Andrew T. Dodson

Food chemistry: Acrylamide is formed in the Maillard reaction

Reports of the presence of acrylamide in a range of fried and oven-cooked foods have caused worldwide concern because this compound has been classified as probably carcinogenic in humans. Here we show how acrylamide can be generated from food components during heat treatment as a result of the Maillard reaction between amino acids and reducing sugars. We find that asparagine, a major amino acid in potatoes and cereals, is a crucial participant in the production of acrylamide by this pathway.

Acrylamide is formed in the Maillard reaction

Reports of the presence of acrylamide in a range of fried and oven-cooked foods have caused worldwide concern because this compound has been classified as probably carcinogenic in humans. Here we show how acrylamide can be generated from food components during heat treatment as a result of the Maillard reaction between amino acids and reducing sugars. We find that asparagine, a major amino acid in potatoes and cereals, is a crucial participant in the production of acrylamide by this pathway.

Acrylamide in potato crisps prepared from 20 UK-grown varieties: effects of variety and tuber storage time.

Highlights • Twenty varieties of field-grown potato were stored for 2 months and 6 months at 8 °C.• Acrylamide contents were measured in crisps prepared from all varieties at both storage times.• The longer storage period did not affect acrylamide formation significantly.• Correlations between acrylamide, its precursors and crisp colour are described and discussed.

The Effect of Cooking on Acrylamide and Its Precursors in Potato, Wheat and Rye

The relationship between acrylamide and its precursors, namely free asparagine and reducing sugars, was studied in simple cakes made from potato flake, wholemeal wheat and wholemeal rye, cooked at 180 degrees C, from 5 to 60 min. Between 5 and 20 min, large losses of asparagine, water and total reducing sugars were accompanied by large increases in acrylamide, which maximized in all three products between 25 and 30 min, followed by a slow linear reduction. Acrylamide formation did not occur to any extent until the moisture contents of the cakes fell below 5%. A comparison of each type of cake with a commercial product, made from the same food material, showed that acrylamide levels in all three commercial products were well below the maximum levels in the cooked cakes.

Antigenotoxic Effect of Kefir and Ayran Supernatants on Fecal Water-Induced DNA Damage in Human Colon Cells

Fermented dairy products and their component bacteria have been shown to possess health-promoting functions in consumers and recently have been suggested to reduce the risk of colorectal cancer. Kefir and ayran are two popular fermented milk drinks that have their origins in the Caucasus region of Russia. The present study aimed to evaluate their potential anticancer properties in colon cells in vitro. The comet assay and transepithelial resistance assay were used to assess the effect of kefir and ayran supernatants on genotoxicity of fecal water samples and on intestinal tight junction integrity. Their antioxidant capacity was measured by trolox equivalent antioxidant capacity assay and compared with that of unfermented milk. The results showed that DNA damage induced by 2 of 4 fecal water samples was significantly decreased by kefir and ayran supernatants and with ayran the effect was dose-dependent. However no effect on intestinal tight junctions was observed. The supernatants of kefir and ayran contained high amounts of acetic and lactic acid but only a very small quantity of caproic and butyric acid, and they showed significantly greater antioxidant capacity than milk. These findings suggest kefir and ayran can reduce DNA damage, which might be due to their antioxidant capacities.

Acrylamide-forming potential of potatoes grown at different locations, and the ratio of free asparagine to reducing sugars at which free asparagine becomes a limiting factor for acrylamide formation

Highlights • Location of cultivation affects potato composition and acrylamide-forming potential.• Effects of variety and storage interact with those of location.• Dramatic differences in free asparagine concentration in potatoes grown at two sites.• Concentration of reducing sugars is the primary determinant of acrylamide formation.• Ratio of free asparagine to reducing sugars determines whether free asparagine affects acrylamide formation.

Aroma formation in beef muscle and beef liver

Beef muscle and beef liver were used as matrices in which to observe the Maillard reaction. Samples were spiked with glucose, ribose, glycine or cysteine and the effect on the formation of pyrazines and furanthiols was studied. The addition of glucose showed that glucose limited the formation of pyrazines in muscle but not in liver. The addition of glycine demonstrated how some pyrazines were reliant on glycine for their formation whereas others were not, confirming reported reaction mechanisms from in model systems. The addition of cysteine showed that in muscle the availability of H2S was the limiting step in the formation of 3-methyl-2-furanthiol (MFT) whereas in liver, MFT could not be detected in any of the systems. This could be due to the absence of ribose in liver, but may also indicate the presence of interactions with the liver matrix.

Reactions of Propylene Glycol with the Constituents of Food Flavorings

Propylene glycol (1,2-propanediol, PG) is a solvent commonly used in the preparation of commercial food flavorings. Under acidic or basic conditions, PG can react with components of food flavorings to give new compounds. Three particular reactions are described: the reaction of PG with aldehydes and ketones to give acetals and ketals, the reaction of PG with organic acids to give mono-and di-esters, and the transesterification reaction of PG with lactones to give dihydroxy esters. The effect of propylene glycol on the sensory quality of stored food flavorings is discussed.

Acrylamide is formed in the Maillard reaction: Food chemistry

Reports of the presence of acrylamide in a range of fried and oven-cooked foods have caused worldwide concern because this compound has been classified as probably carcinogenic in humans. Here we show how acrylamide can be generated from food components during heat treatment as a result of the Maillard reaction between amino acids and reducing sugars. We find that asparagine, a major amino acid in potatoes and cereals, is a crucial participant in the production of acrylamide by this pathway.