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Browning Reaction

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Maillard Reaction & Nutritional Effect
aillard reaction may result in a reduction in nutritional properties and the formation of potentially toxic and mutagenic compounds. In a food system, the reactants are mostly amino acids (free forms or peptide-bound) and reducing sugars. Since up to 50% of our food groups have been processed before consumption, some of the amino acids and reducing sugars is lost during processing.
Which amino acid is in the greatest danger?

Maillard reactions affect protein bioavailability by derivatizing protein-bound, dietary limiting amino acids such as lysin, arginine, and histidine. Maillard reaction products also exhibit antinutritive effects by mechanism involving complexation with micronutrients, dstruction of vitamins, and by acting as inhibitors of digestive enzymes.
In addition, the product of the maillard reaction, melanoidin, present in the incubation medium was found that there was negative effect on the uptake of sucrose through the everted sac of small intestine. Results from recent studies also showed that the consumption of heterocyclic amines arise from cooked meat might be associated with cancer development in human. (See section in Maillard Reaction in Medicine for more details.)
oreover, evidence has shown that spray-drying of infant formulae which contains more lactose, may give up to 10% lysine blockage as does high-temperature shot time (HTST) sterilization of liquid milk. Specialized formulae, such as lactose-hydrolysed milks or formulae containing glucose intolerant infants, give the greatest problems during drying. Why?
ith the combination of lactose and lysine losses during heat treatment in milks, Maillard reaction products are formed. The brown pigment (melanodin) is responsible for the increased specific activities of small intenstinal disaccharidases which eventually yields lower sugar absorption. Therefore, the food processing does influence the food quality in terms of the nutritional aspect.

Case Study: Effects of Malenoidin in Rats.

Experiment: The rats were divided into three groups and fed by basal diet, 2% melanoidin diet and 4% melanoidin respectively. Some results are listed as below.

The reduction of gatro-intestinal transit time reflects the ability of melanoidin topromote transfering the intestinal contents through digestive tract, which is considered to be on the hydrophilic properties of the pigments. The moisture of caecal contents and feces increased with the uptake of melanoidin. This effect is similar to that of dietary fiber.

In the mucosal membrane of small intestine, there are few disaccharidases present, such as sucrase, maltase and lactase. But the increased amount of melanoidin would increase the specific activities of disaccharidases. The rise of specific activity of disaccharidases is a compensatory response to prevent the reduced utilization of sugar.

The result also showed that the addition of melanoidin to the incubation medium inhibited the uptake of sucrose in contrast to D-glucose which was scarcely affected and that melanoidin interfered with the action of sucrose instead of functioning and transporting the sugar to the intestinal wall.

Infant formulae should be carefully treated or processed because this is the basic foodstuffs for a baby. The nutritional value of infant formulae should be retain even though the heat is applied.

Next(Question 2: Maillard Reaction Products and Antioxidantive Effects)

301 Home : Course Modules/ Browning / Maillard Reaction & Nutritional Effect

	The reduction of gatro-intestinal transit time reflects the ability of melanoidin topromote transfering the intestinal contents through digestive tract, which is considered to be on the hydrophilic properties of the pigments. The moisture of caecal contents and feces increased with the uptake of melanoidin. This effect is similar to that of dietary fiber.
	In the mucosal membrane of small intestine, there are few disaccharidases present, such as sucrase, maltase and lactase. But the increased amount of melanoidin would increase the specific activities of disaccharidases. The rise of specific activity of disaccharidases is a compensatory response to prevent the reduced utilization of sugar.