Melanoidins are brown, high molecular weight heterogeneous polymers that are formed when

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...

s and

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

s combine (through the Maillard reaction) at high temperatures and low water activity. They were discovered by Schmiedeberg in 1897. Melanoidins are commonly present in foods that have undergone some form of

non-enzymatic browning Browning is the process of food turning brown due to the chemical reactions that take place within. The process of browning is one of the chemical reactions that take place in food chemistry and represents an interesting research topic regarding ...

, such as barley malts (

Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...

and

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), bread crust, bakery products, and coffee. They are also present in the wastewater of sugar refineries, necessitating treatment in order to avoid contamination around the outflow of these refineries. Dietary melanoidins themselves produce various effects in the organism: they decrease Phase I

liver enzyme Liver function tests (LFTs or LFs), also referred to as a hepatic panel or liver panel, are groups of blood tests that provide information about the state of a patient's liver. These tests include prothrombin time (PT/INR), activated partial t ...

activity and promote

glycation Glycation (non-enzymatic glycosylation) is the covalent bond, covalent attachment of a sugar to a protein, lipid or nucleic acid molecule. Typical sugars that participate in glycation are glucose, fructose, and their derivatives. Glycation is th ...

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, an ...

'', which may contribute to

diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...

, reduced vascular compliance, and

Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...

. Some of the melanoidins are metabolized by the intestinal microflora. Coffee is one of the main sources of melanoidins in the human diet, yet coffee consumption is associated with some health benefits and antiglycative action.

Footnotes

References

Food science Substances discovered in the 19th century {{organic-compound-stub