Mutagenic factors in cooked foods

Area of Science:

• Food Chemistry
• Toxicology
• Mutagenesis Research

Background:

• Charred food surfaces, particularly fish and beef, exhibit significant mutagenic activity.
• Pyrolysis products of proteins and amino acids are identified as major contributors to this mutagenicity.
• Existing knowledge includes mutagens like benzopyrene and nitroso compounds in cooked foods.

Purpose of the Study:

• To identify and characterize mutagenic compounds formed during food pyrolysis.
• To investigate the mutagenic potential of specific amino acid pyrolysis products.
• To review the mutagenicity of charred products from various foods, including vegetables, seaweed, and garlic.

Main Methods:

• Utilized Salmonella typhimurium test strains with S-9 mix for mutagenicity assays.
• Isolated and purified novel gamma-carboline derivatives from tryptophan pyrolysis products.
• Assessed mutagenicity of purified compounds and compared them to known mutagens like aflatoxin B1.
• Investigated the co-mutagenic effects of beta-carboline derivatives (norharman, harman) with other compounds.

Main Results:

• Tryptophan, serine, and glutamic acid pyrolysis products showed high mutagenic activity.
• Two new gamma-carboline derivatives from tryptophan were identified as potent mutagens, stronger than aflatoxin B1.
• These gamma-carbolines also demonstrated in vitro transformation of hamster embryo cells.
• Norharman and harman acted as co-mutagens, significantly increasing mutagenicity when mixed with aniline or o-toluidine.
• Flavonoids like kaempferol and quercetin, and their glycosides, were found to be mutagenic in cooked vegetables.

Conclusions:

• Pyrolysis of proteins and amino acids generates potent mutagens, including novel gamma-carbolines.
• These newly identified gamma-carbolines represent a significant class of food mutagens.
• The mutagenicity of cooked foods is complex, involving various compounds including amino acid derivatives, flavonoids, and known carcinogens.