What is maltose?

Maltose or malt sugar is a disaccharide composed of two glucose molecules connected with an alpha (1,4) glycosidic bond. Maltose is not an essential nutrient, which means you do not need to get it from food in order to live an be healthy.

Name origin: from malt = soft grain; -ose denotes sugar.

Maltose Formula

Maltose structure

Picture 1. Maltose structure

Nutrition Facts for Maltose

  • Calories per gram = 4
  • Glycemic index for 50 g (GI) = 105 [9]
  • Sweetness, relative to sucrose = 50% [21]
  • Net carbohydrates = 100%

Maltose Function in the Human Body

Maltose is a source of energy; it can provide about 4 Calories per gram,which is about the same as glucose or sucrose.

Maltose Sources

  • Maltose is an intermediate product of the starch digestion.
  • Free maltose (as a disaccharide) in significant amounts is naturally present in spelt, kamut and sweet potatoes [1].
  • Syrups high in maltose: high maltose corn syrup (HMCS), barley malt syrup, also called barley malt sugar or dark malt syrup (which is a thick brown syrup), brown rice syrup, corn syrup [1].
  • Beverages containing maltose: certain beers, ciders, compotes, kombucha rice malt, “malt beverages” (non-alcoholic).
  • Processed foods high in maltose: certain ready-to-eat cereals, jelly candies, chocolates, compotes, caramel sauce, confections (especially in China, Taiwan, Hong Kong) [1,2].

Chart 1. Foods High in Free Maltose

Beer, strong ale, 8 vol% alco (12 oz, 355 mL) 22
Barley malt syrup (1 tbsp, 20 g) 12-15
High maltose corn syrup (HMCS) (1 tbsp, 20 g) 4.5-13.5
Sweet potato, baked (1 cup, mashed, 200 g) 13
High maltose corn syrup (HMCS, 65% maltose) (1 tbsp, 20 g) 10
Beer, lager, 4.7 vol% alco (12 oz, 355 mL) 7.5
Brown rice syrup (1 tbsp, 20 g) 7
Ready-to-eat cereals (1/2 cup, dry) 6
Cider, 4.7 vol% alco (12 oz, 355 mL) 2-6
Pears, canned, solids and liquids (1 cup, 265 g) 5
Jelly candies (2 oz, 57 g) 4
Pizza, meat and vegetables (1 slice, 150 g) 3.5
Sundae, caramel (1 piece, 165 g) 3.5
Peaches, canned, solids and liquids (1 cup, 250 g) 3.5
Shake, strawberry (1 cup, 237 mL) 3.5
Bagel, plain (3.5 oz, 100 g) 3
Bread, whole wheat (two slices, 6“x 4“ x ½”, 3.5 oz, 100 g) 3
Grapes (1 cup, 90 g) 3
Light corn syrup (1 tbsp, 20 g) 3
Guava nectar, canned (1 cup, 237 mL) 2
Dark corn syrup (1 tbsp, 20 g) 2
Pancake syrup (1 tbsp, 20 g) 2
Nougat candy (1 oz, 28 g) 2
Beer, alcohol free (12 oz, 355 mL) 1
Steak, breaded (1 piece, 175 g) 1
Honey (1 tbsp, 21 g) Up to 1

Chart 1 references: [1], [2]

Maltose Digestion

In the small intestinal lining, the enzymes maltase and isomaltase break down maltose to two glucose molecules, which are then absorbed. Glucose from maltose is absorbed faster than pure glucose [5]. Some maltose can be absorbed as such, without being broken down into glucose [6]. Maltose and its digestion product glucose attract water from the intestinal wall (osmotic effect) so they can cause diarrhea if consumed in excess. The laxation threshold for maltose in healthy people is about 120 grams per day [7-p.320].

Maltose and Dental Caries

Maltose, including maltose released from the digestion of starch in mouth, can promote dental caries.

Maltose Intolerance

Individuals with a congenital sucrase-isomaltase deficiency may experience bloating and diarrhea after ingesting maltose, sucrose or starch [8].

Maltose, Blood Glucose Levels and Diabetes

  • Maltose has a high glycemic index (GI = 105) [9] and can cause greater blood glucose spikes than sucrose.
  • An antidiabetic drug acarbose inhibits the digestion of maltose, which results in slower glucose absorption and lower blood glucose spikes after carbohydrate meals [10].

Who can benefit from avoiding/limiting maltose intake?

Individuals with the following conditions can benefit from avoiding maltose:

  • Diabetes mellitus
  • Celiac disease [20]
  • Reactive hypoglycemia [11]
  • Postprandial hypotension [12]
  • Glucose-galactose malabsorption [13]
  • GLUT-1 deficiency syndrome [14]
  • Congenital sucrase-isomaltase deficiency (CSID) [8]

Maltose Production

Maltose is produced from corn, barley, tapioca or sago palm starch using the enzyme alpha-amylase of fungal origin [3,4,producers].

Maltose and Cooking

  • Maltose powder is commercially available as maltose, maltose sugar or malt sugar, which is a white crystalline substance without odor, 50% as sweet as sucrose [21]. Chemically, maltose powder is usually in a form of maltose monohydrate (each maltose molecule is connected with one water molecule).
  • Maltose monohydrate is very hygroscopic; it readily attracts moisture at 60% relative humidity [15-p.86].
  • Solubility of maltose monohydrate in water at 68 °F (20 °C) is 108 g/100 mL [16].
  • Maltose monohydrate melting point is 216.5-266 °F (102.5-130 °C) [16,22]. During 30-minutes cooking at 356 °F (180 °C), most of maltose decomposes [17-p.267].
  • Maltose is a reducing sugar [18], so it takes part in the Maillard browning reaction with amino acids.
  • Caramelization of maltose starts at 356 °F (180 °C) [19].
  • Maltose is a fermentable sugar, so it can be used in the production of beer [23].

  1. List of foods high in maltose US Department of Agriculture
  2. List of foods high in maltose
  3. Production of maltose by using enzymatic starch hydrolysis  Universiti Teknologi Malaysia
  4. Production of syrups containing maltose  London South Bank University
  5. Jones BJM et al, 1983, Glucose absorption from starch hydrolysates in the human jejunum  Gut
  6. Miller LJ et al, 1978, Postprandial duodenal function in man  PubMed Central
  7. Mitchell H, 2006, Sweeteners-and-Sugar-Alternatives-in-Food-Technology
  8. Congenital sucrase-isomaltase deficiency  Genetics Home Reference
  9. Foster-Powel K et al, 2002, International table of glycemic index and glycemic load values: 2002  The American Journal of Clinical Nutrition
  10. Acarbose
  11. Todd B et al, I think I have reactive hypoglycemia. How can I address my symptoms?  Mayo Clinic
  12. Van Orshoven NP et al, 2010, Postprandial Hypotension in Clinical Geriatric Patients and Healthy Elderly: Prevalence Related to Patient Selection and Diagnostic Criteria  Hindawi
  13. Glucose-galactose malabsorption  Genetics Home Reference
  14. GLUT1 deficiency syndrome  Genetics Home Reference
  15. Wrolstad E, 2011, Food Carbohydrate Chemistry
  16. Maltose monohydrate MSDS  Fischer Scientific
  17. Friedman M et al, 2004, Chemistry and Safety of Acrylamide in Food
  18. Reducing and non-reducing sugars  Aus-e-tute
  19. Caramelization  Minnesota State University Moorhead
  20. Is it safe for me to consume maltose?  University of Chicago, Celiac Disease Center
  21. Relative Sweetness Values for Various Sweeteners  Owl Software
  22. D-maltose monohydrate  Sigma-Aldrich
  23. Fermentable sugar and non-fermentable sugar  Malting and Brewing

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