Unformatted text preview: t forms are chair boat better representations of their actual structures their The furanose rings are The present as either envelope or twist conformations Which is the more stable form? Other important monosaccharides monosaccharides Sugar alcohols Sugar No carboxyl group Can be produced by Can reducing monosaccharides reducing Unusual sweet taste (cool) Popular in sugar free Popular applications applications Slowly absorbed Contribute calories 100g Extra ® gum = 60g 100g sugar alcohols = 165 kcal sugar Can have laxative effect Can Humectants lower aw Humectants Used to protect proteins in Used freezing and drying applications applications Safe and non-browning Disaccharides Disaccharides Classified by many as the smallest oligosaccharides Classified Formed by a condensation reaction between 2 Formed monosaccharide units forming a glycosidic bond glycosidic Most common: Sucrose Lactose Maltose Sucrose (table sugar) Sucrose Note that Fru Naturally present Naturally has been flipped Popular ingredient in foods Popular and that it is in the (very large daily consumption) (very β -position Used widely in fermentation Different commercial forms Composed of glucose and Composed glucose α -1-2 fructose fructose The glycosidic bond is formed The between the anomeric carbons of Glu and Fru carbons This renders the anomeric This carbons non-reactive and the The bond can be broken by hydrolysis sugar is therefore called a - Enzyme (fructosidase invertase) NON-REDUCING sugar NON-REDUCING - Acid/heat Product called invert sugar Maltose Maltose 2 units of glucose Forms from the breakdown of starch during malting of grains Forms (barley) and commercially by using enzymes (β -amylase) (barley) E.g. malt beverages; beer Used sparingly as mild sweetener in foods Very hygroscopic OH-group can be reactive and we term this as a REDUCING OH-group SUGAR SUGAR Is free to react with oxidants α -1-4
Reducing end Lactose Lactose Galactose and glucose The only sugar found in milk 4.8% in cows 6.7% in humans The primary carbohydrate The source for developing mammals source Stimulates uptake and retention Stimulates of calcium of Milk Unfermented dairy products Fermented dairy products Fermented β -1-4 Food products Reducing end Cleaved by lactase (enzyme) Contain less lactose Lactose converted to lactic acid Lactose
Problems with lactose in foods Problems A) Crystallization during drying Appearance of glass in milk powder Sandy texture in ice cream Sometimes dissolved while other times it will not dissolve α-D-lactose VERY INSOLUBLE (5 gm/100 ml) Causes the glass-like appearance in foods β -D-lactose MORE SOLUBLE (45 gm/100 ml) If α>>β more α will form If Limits amounts of milk solids one can use in formulations Quick drying get non-crystalline lactose (amorphous) no Quick crystalline form crystalline Slow drying or concentration more crystalline lactose Slow Lactose Lactose
B) Color and flavor Lactose is a reducing sugar Can react with proteins and form undesirable color Can and flavors and Problem with dairy product and dairy ingredients, Problem especially during drying, concentration and heating especially Some lack enzyme lactase C) Lactose intolerance Age and ethnic group related Gas, bloating, diarrhea, acid buildup Lactase lactic acid = problem for the intestines Lactase Several ways to prevent or minimize this problem Tri- and tetrasaccharides TriGalactosylsucroses Raffinose (3) and Stachyose (4) Found primarily in legumes Found legum...
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- Spring '08
- Glucose, Carbohydrate, Fructose