Contamination of food by heterocyclic amine compounds and its prevention

作者：admin  点击次数：12  发布时间：2025-04-18

Heterocyclic amines include amino-imidazoaza-arenes (AIAs) and amino-carbolines. AIAs include I0, IQ, and IP. The α-amino group of the azole ring of AIAs can be converted into N-hydroxy compounds in the body and have carcinogenic and mutagenic activity. AIAg is also called IQ-type heterocyclic amine, and the amino group on its guanidine group is not easily removed by sodium nitrite. Aminocarbolines include α-carboline, γ-carboline, and 8-carboline, and the amino group on its pyridine ring is easily removed by sodium nitrite and loses its activity. Most heterocyclic amine compounds come from roast beef or roasted sardines, pyrolysis of tryptophan or glutamic acid, and pyrolysis of threonine, glycine, creatinine and glucose.
(I) Mutagenicity of heterocyclic amines
Heterocyclic amines are mutagenic only after metabolic activation. The active metabolites of heterocyclic amines are N-hydroxy compounds. Heterocyclic amines can be N-oxidized under the action of cytochrome P450IA2, and then the N-hydroxy metabolites are converted into terminal mutagens by the action of 0-acetyltransferase and sulfotransferase.
(II) Carcinogenicity of heterocyclic amines
Heterocyclic amines are carcinogenic to rodents to varying degrees. Their main target organs are the liver, followed by blood vessels, intestinal forestomach, mammary glands, clitoral glands, lymphatic tissues, skin and oral cavity. Studies have shown that some heterocyclic amines are also carcinogenic to primates.
Heterocyclic amines can induce the cytochrome P450 enzyme system (cylochrome P450s, CYP), thereby promoting their own metabolic activation. The N-hydroxy metabolites of heterocyclic amines can directly bind to DNA, but their activity is low. Most heterocyclic amines form the largest amount of adducts in the liver, followed by tissues such as the intestine, kidney and lung. The formation of DNA adducts can lead to genetic effects such as gene mutations and inactivation of tumor suppressor genes. This may be one of the main mechanisms of heterocyclic amine carcinogenesis. (III) Sources of heterocyclic amines
Heterocyclic amine compounds in food are mainly produced during high-temperature cooking, especially fish and meat foods rich in protein are more likely to be produced during high-temperature cooking. The influencing factors are mainly the following two aspects.
1. Cooking method
The precursors of heterocyclic amines are water-soluble, and the heating reaction mainly produces AIAs heterocyclic amines. Temperature is an important factor affecting the formation of heterocyclic amines. When the temperature rises from 200℃ to 300℃, the amount of heterocyclic amines generated can increase by 5 times. The frying time also has a certain influence. At a frying temperature of 200℃, heterocyclic amines are mainly formed in the first 5 minutes. The moisture in food is an inhibitory factor for the formation of heterocyclic amines. Therefore, the higher the heating temperature, the longer the time, and the lower the moisture content, the more heterocyclic amines are produced. Therefore, the cooking methods such as burning, roasting, frying, and deep-frying, which are directly in contact with fire or hot metal surfaces, produce much more heterocyclic amines than stewing, braising, simmering, boiling, and microwave cooking, which have lower temperatures and more moisture. 2. Food ingredients
Under the same cooking temperature, time and water content, foods with different nutritional ingredients produce very different types and quantities of heterocyclic amines. Generally speaking, foods with higher protein content produce more heterocyclic amines, and the amino acid composition of protein directly affects the types of heterocyclic amines produced. Creatine or creatinine is the main source of the a-amino-3-methylimidazole part of heterocyclic amines, so foods containing muscle tissue can produce a large amount of AIAs (IQ type) heterocyclic amines. The Maillard reaction is closely related to the production of heterocyclic amines. This reaction can produce a large number of heterocyclic substances (up to more than 160 types), some of which can further react to form heterocyclic amines.
Normally cooked foods often contain a certain amount of heterocyclic amines, but the content of various heterocyclic amines detected in different foods is not completely consistent. The heterocyclic amines detected in fried beef (300℃, 10min) were PhIP15ng/g, IQ0.02ngg, 8-MeIQ10ng/g, 4,8-DiMeIQ, and 0.6ng/g, accounting for 93%, 0.12%, 6.2% and 0.37% of the total AIAs, respectively.