NUT 1104 Food Sciences I 2024 Fall Term Lecture 2 - Carbohydrates PDF

NUT 1104 Food Sciences I 2024 Fall Term Ezgi Pulatsu, Ph.D. School of Nutrition Sciences University of Ottawa/ Université d'Ottawa  2 Course Content Module 1...

NUT 1104 Food Sciences I 2024 Fall Term Ezgi Pulatsu, Ph.D. School of Nutrition Sciences University of Ottawa/ Université d'Ottawa  2 Course Content Module 1 Module 2 Module 3 Module 4 INTRODUCTION FOOD COMPONENTS and CHEMISTRY FOOD and FOOD MATERIALS FOOD ADDITIVES and FOOD SAFETY 3.1 Meat, Poultry and 4.1 Food Additives 1.1 Course Introduction 2.1 Water Fish 4.2 Food Safety Syllabus 2.2 Carbohydrates 3.2 Eggs and Dairy Course content 2.3 Proteins 3.3 Legumes, Pulses and Course calendar 2.4 Lipids Cereals Rules 2.4 Vitamins and 3.4 Flour and Pasta Regulations Minerals 3.5 Bread and Baked Goods 3.6 Chocolate  3 Course Calendar  4 Course Calendar Book 1) Essentials of Food Science, 5th Edition 2021 Vaclavik, Vickie, author.; Christian, Elizabeth W.;Campbell, Tad. Book 2) Fennema's Food Chemistry, 4th Edition, Kirk L. Parkin, Owen R. Fennema (Editors), ISBN: 9780429195273.3) Book 3) Understanding food: principles and preparation, Brown, A. C., Walter, J. M., & Beathard, K. (2015). Boston, MA, USA: Cengage learning.  5 Learning outcomes Become familiar with the chemistry and structure of carbohydrates Understand the relationships between the chemical structure and properties Identify food polysaccharides and their interactions with other molecules Discuss the relevance and importance to stability and quality  6 Outline Introduction Carbohydrates Nomenclature Structure Chemistry Properties Summary  7 Introduction Carbohydrates are structural components of living organisms have many different molecular structures, sizes, and shapes exhibit a variety of chemical and physical properties differ in their physiological effects on the human body. can be modified through chemical, biochemical, and in some cases physical means commercially advantageous – improved and extended use Fennema’s Food Chemistry, pp 90-169  8 Introduction Carbohydrates significant energy source for both plants and animals through oxidation in foods, on the other hand, used as sweeteners, stabilizers, gelators, or water retention agent chemically; polyhydroxy aldehydes or polyhydroxy ketones ,Kontogiorgos, pp 90-169 V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  9 Introduction Carbohydrates 𝐶𝑥 (𝐻2 𝑂)𝑦 most natural carbohydrate is in the form of oligomers (oligosaccharides) or polymers (polysaccharides) comprised of simple and modified sugars, with low-molecular-weight carbohydrates most often produced by depolymerization of natural polymers Fennema’s Food Chemistry, pp 90-169  10 Introduction Carbohydrates are categorized into three groups Monosaccharides simplest form building blocks of the rest of the carbohydrates sometimes referred to as simple sugars cannot be broken down to simpler carbohydrate molecules by hydrolysis Oligosaccharides Polysaccharides Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  11 Introduction Carbohydrates are categorized into three groups Monosaccharides Disaccharides - Oligosaccharides linked monosaccharides → larger molecules disaccharides → composed of two monosaccharides 3-20 units of monosaccharides → oligosaccharides Polysaccharides Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  12 Introduction Carbohydrates are categorized into three groups Monosaccharides Oligosaccharides Polysaccharides >20 monosaccharides, frequently >200 units have distinct properties from the other two classes known as polymers of monosaccharides Fennema’s Food Chemistry, pp 90-169  13 Chemistry Carbohydrates composed of chiral carbon atoms, each of which has four different, chemically distinct atoms or chemical groups attached to it → leading to two different spatial arrangements of atoms around a given chiral center. Image source: link Fennema’s Food Chemistry, pp 92  14 Chemistry Fennema’s Food Chemistry, pp 93  15 Fennema’s Food Chemistry, pp 94  16 Monosaccharides- structure Either aldoses (e.g., glucose) when they carry an aldehyde functional group or ketoses (e.g., fructose) when they carry a ketone functional group Only ketose relevant to food chemistry is fructose Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  17 17 Image source: link  18 Monosaccharides- structure have ≥ 4 carbon atoms (4C) relevant monosaccharides to food processing: Glucose and fructose → contain 6C Arabinose or xylose → contain 5C For food applications, the six most essential monosaccharides are: 1. Glucose 3. Galactose 5. Xylose 2. Mannose 4. Arabinose 6. Fructose  19 Monosaccharides- structure The numbering of carbon atoms starts from the carbonyl group ***Correct carbon numbering is essential for understanding chemical reactions, polysaccharide linkage and properties Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  20 Monosaccharides- structure Isomer forms exist in monomers Stereoisomerism: atoms connect in the same order but differ in spatial arrangement Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  21 Monosaccharides- structure ***Carbohydrates exhibit complex isomeric forms due to the presence of multiple chiral carbon atoms Sugars contain one or more chiral carbon, 2n different arrangement exist where n is the number of chiral carbon atoms E.g., Glucose → 4 Chiral carbon and therefore 24 = 16 different isomers Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  22 Monosaccharides- structure ***D- sugars → the hydroxyl group on the highest numbered chiral carbon atom positioned on the right- hand side ***L-sugars→ those with the hydroxyl group on the left Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  23 Monosaccharides- structure D-and L- monosaccharides are enantiomers, because they are mirror images of one another Carbohydrates can be found in D-form naturally D- and L- are written as small capital letters → notation Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  24 Disaccharides- Oligosaccharides Disaccharides = monosaccharide + monosaccharide glucose and galactose also retains the anomeric C-1 two glucose glucose and fructose linked by an α-(1 → 2) glycosidic bond Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  25 Disaccharides- Oligosaccharides Oligosaccharides very few of them occur naturally raffinose (tri- saccharide), stachyose (tetrasaccharide) and verbascose (pentasaccharide) are some commonly occurring oligosaccharides of beans that are non-digestible and responsible for flatulence. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  26 Disaccharides- Oligosaccharides Oligosaccharides between two and twenty monosaccharides (if disaccharides are included) linked with glycosidic bonds, Fructans → Fructo-oligosaccharides are naturally occurring and consist of multiple units of fructose. Foods rich in fructans asparagus, banana, garlic, leek, onion, and Jerusalem artichoke. commonly occurring fructans are inulin and levan with fructose units linked by β-(2 → 1) or β- (2 → 6) bonds. “prebiotics” inducing the growth of beneficial bacteria in the gut, as fat replacers, or texture modifiers. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  27 Polysaccharides Polymers of monosaccharides linked via glycosidic bonds. Also known as polysaccharide chain and the number of monosaccharides in that chain is termed as degree of polymerization (DP). E.g., If DP=200, then the number of monosaccharides in the polymer chain is 200. DP for polysaccharides is generally >200, frequently over 3000. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  28 Polysaccharides-sources From plants with minimal processing E.g., rice, potato starch From agricultural wastes E.g., pectin From other sources Algae→ e.g., alginate, carrageenan By-products of shellfish industry→ e.g., chitin Microbial fermentation → e.g., xanthan, gellan Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  29 Polysaccharides- composition Based on composition, polysaccharides are categorized into Homo- Hetero- polysaccharides polysaccharides The same monosaccharide unit Two or more different monosaccharides Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  30 Polysaccharides-structure Linear → only one type of glycosidic bond OR Branched → multiple types of glycosidic bonds occur in the same molecule Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  31 Polysaccharides-structure Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  32 Polysaccharides Despite the large number of monosaccharides, relatively small number of monosaccharides found in polysaccharides Common monosaccharides in polysaccharides are Glucose and mannose → forming the backbone of some of the most important commercial polysaccharides Other sugars or sugar acids: galactose, xylose, arabinose or galacturonic, guluronic and mannuronic acids Think of amylose and cellulose → both consist of glucose Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  33 Amylose Cellulose Consists of glucose Consists of glucose Glycosidic linkage: 𝛂- Glycosidic linkage: β- (1→4) (1→4) Linear polysaccharide Linear polysaccharide They have different functions in the plant (structural vs source of energy), also when we use them as food ingredients. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  34 Where does the diversity come from? The type of linkages, isomeric forms functionalization of monosaccharides, branching, and, periodicity of the monomers in the backbone Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  35 Polysaccharides Essential food ingredients Non-starch polysaccharides→ “gum” E.g., gum Arabic, guar gum, gum tragacanth, xanthan gum Functions of polysaccharides Bulking agents, emulsion stabilizers, fat replacers, gelation agents, thickening agents, viscosity enhancers, water-binding agents, or texture modifiers Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  36 Polysaccharides Therefore, their functionality is either structure formation or structure stabilization They form gels → hold large amount of water in They increase viscosity their soft-solid three- → prevent physical dimensional structure separation (e.g., E.g., can be used in creaming, separation) batters, jams. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  37 Polysaccharides Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  38 Starch Found in tubers, fruits and seeds in plants Used in food and non-food industries Source: corn, wheat, rice, potato, or cassava Native→ not processed Native starches can be physically, chemically or enzymatically modified The unique chemical and physical characteristics and nutritional aspects of starch Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  39 Starch Found in the starch granule Mixture of two polysaccharides: amylose and amylopectin → they are both glucose homo-polysaccharides, and they only differ in branching in amylose 𝛂-(1→4) linkages in amylopectin both 𝛂-(1→4) and 𝛂 -(1→6) Amylose vs Amylopectin Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  40 Starch Amylose vs Amylopectin Fennema’s Food Chemistry, pp 90-169 Amylopectin is found in all common starches, and constitutes about 75% (weight basis) of these starches If entirely amylopectin → waxy starch 41  42 Starch 𝛂-(1→4) linkages both 𝛂-(1→4) and 𝛂 -(1→6) Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  43 Starch Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  44 Starch ****Starch gelatinization: disruption of the molecular order within the granule, leading to loss of crystallinity, amylose leaching, and starch solubilization Gelatinization occurs in a range (∼55-95°C) Factors affecting initial temperature 1. starch type 2. starch-to-water ratio 3. pH 4. Concentration ***Starch retrogradation: upon cooling of starch paste, recrystallization of amylose and amylopectin Rate of amylose recrystallization>> Rate of amylopectin recrystallization Hence, waxy starches → no appreciable retrogradation Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  45 Maltodextrin vs glucose syrup ** Maltodextrins→ oligosaccharides with up to 20 glucose units linked with α(1→4) glycosidic bonds ** glucose syrups are starch hydrolysates DE= dextrose equivalence → a measure of extent of hydrolysis → measures the reducing sugars in the hydrolysate 0-100 % Pure glucose =100 and starch =0 % Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  46 Carrageenan Linear, sulphated galactan composed of alternating 3-linked β-D- galactose and 4-linked α-D-galactose or 4-linked 3,6-anhydro-α-D-galactose Has disaccharide repeating unit and is obtained from seaweeds Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  47 Alginates The salts of alginic acid, but it also refers to all the derivatives of alginic acid and alginic acid itself Structural components of brown seaweed present in the form of divalent salts of alginic acid and form the intercellular gel matrix Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  48 Alginates Alginate backbones consist of sequences of blocks of mannuronic acid (M-blocks) or guluronic acid (G-blocks) and regions of alternating sequences (e.g., MG, MMG, GGM) Linear polysaccharides composed of β-D-mannuronic acid (M) and α-L- guluronic acid (G) linked via (1 → 4) glycosidic linkages Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  49 Alginates The M-blocks are linked via β-(1 → 4) linkages → flexibility due to 4C1 conformation G-blocks → rigid structure due to the 1C4 conformation of guluronate residues linked via α-(1 → 4) Therefore, the stiffness of the blocks on the backbone is in the order (most rigid) GG > MM > MG (least rigid) Selective in binding divalent and multivalent cations Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  50 Alginates Gelation → egg-box model Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  51 Alginates Gelation → egg-box model Fennema’s Food Chemistry, pp 90-169  52 Pectin family of complex polysaccharides containing 1,4-linked α-D-galactosyluronic residues isolated from plant cell walls, 'waste' citrus peel and apple pomace underripe fruit has more pectin than fully ripe fruit  53 Pectin primarily consists of homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) segments inter- and intramolecular interactions between these two segments alter its functional properties HG is the most abundant which has long chains of linear 1 → 4 linked α- D-galacturonic acid residues (~200 units). Depending on the plant species, some of the carboxyl groups are methyl-esterified at the C-6 position and acetyl-esterified at the O-2 and O-3 positions of the galacturonic acid.  54 Pectin primarily consists of homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) segments RG-I involves the repeating disaccharide galacturonic acid and rhamnose [α- (1 → 2)-D-galacturonic acid–α-(1 → 4)-L-rhamnose]n, n can be > 100 RG-I segments usually have galactose or arabinose branches that may carry a significant amount of protein. The RG-I segment of the molecule is also known as the hairy region due to branching, whereas the HG segment lacking branching is called the smooth region.  55 Pectin Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  56 Pectin Pectin is one of the critical components of cell wall. Diagram of the location of pectin in cell walls Image source: link  57 Pectin High pectin containing fruits → tart apples, crab apples, sour plums, Concord grapes, quinces, gooseberries, red currants and cranberries Fruits with low pectin → apricots, blueberries, cherries, peaches, pineapple, rhubarb and strawberries are low in pectin Pectin use in foods: a gelling agent, stabilizer, emulsifier, and thickening agent jams, bakery fillings, confectionery products, tomato-based products, beverages, and low pH milk products Source: link  58 Pectin Degree of esterification (DE) is % of esterified galacturonic acid units out of the total number of galacturonic acid units in pectin. Two types of commercially available pectin 1. high methoxy pectins (HM-pectin) with DE > 50% 2. low methoxy pectins (LM-pectin) with DE < 50%. Source: link  59 What is the difference between HM-pectin and LM- pectin? Gelation mechanism HM pectin → gelation occurs at pH < 3.5 in the presence of high sucrose concentration, and gel stabilization happens through hydrophobic interactions due to sucrose-induced dehydration of pectin chains LM pectin → at wider pH range, it does not require sucrose, but it needs Ca 2+ and forms ionic bridges between different pectin chains  60 Cellulose the major cell-wall component of plants and is composed of D-glucose connected via β-(1 → 4) glycosidic bonds insoluble in water and indigestible by human digestive enzymes → make it the major component of dietary fiber. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  61 Cellulose Cellulose derivatives can be created which are soluble in water Carboxymethyl-cellulose (CMC) → a carboxymethyl group is attached after etherification and can be used to control ice crystal growth in ice creams. Methylcellulose (MC) is cold-water-soluble and forms thermoreversible gels on heating. MC gels are stabilized through hydrophobic interactions between methyl groups belonging to different chains. MC is used in vegan burgers and vegetarian alternatives, due to its thermoreversible gel formation upon heating but on cooling gel melts and yields viscous solution Microcrystalline cellulose (MCC) is partially depolymerised cellulose, water- soluble, and can be used as a non-caloric filler in food products. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  62 Cellulose Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  63 Galactomannans Seed polysaccharides, commercially obtained mostly from guar and carob (locust bean) having a backbone of β-(1 → 4)-linked mannose with galactose branches linked with α-(1 → 6) glycosidic bonds the mannose-to-galactose ratio (M/G) is the distinctive feature (changes based on the source) Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  64 Galactomannans M/G ratio for guar is 2:1 and 4:1 for carob gum form viscous solutions at low concentrations can be used together with xanthan or carrageenan to improve the stabilizing or gelling properties Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  65 Galactomannans Commonly used in ice cream to prevent ice recrystallization during storage, salad dressings to improve viscosity and water holding capacity, or soft cheese products to improve spreading. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  66 Galactomannans Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  67 Gum Arabic An exudate gum of acacia trees (A. senegal or A. seyal) Species that give the best gum are the Sudan and Nigeria A heterogeneous material, but generally consists of two primary fraction: 1) is composed of polysaccharide chains with little or no protein (accounts for about 70% of the gum). 2) the other fraction contains higher molecular weight molecules that have protein as an integral part of their structures. Fennema’s Food Chemistry, pp 90-169  68 Gum Arabic A highly branched heteropolysaccharide with β-(1 → 3) galactose forming the backbone and branches at the C-6 position involving galactose, arabinose, rhamnose and glucuronic acid This structure is attached to a protein component which affects the functionality of the gum. technologically important polysaccharide-based emulsifier Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  69 Gum Arabic Highly water-soluble, Forms low viscosity solutions even at very high concentrations (20–30%), Can emulsify flavour oils (e.g., orange oil) in the confectionery and beverage industry (e.g., fruit flavoured beverages) without giving a slimy texture to the product. Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  70 Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  71 Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  72 Xanthan Heteropolysaccharide produced by the bacterial fermentation of Xanthomonas campestris soluble in hot and cold water has a cellulose backbone, and every alternate glucose residue has a three- sugar side chain consisting of two mannose residues with a glucuronic acid residue can be considered as cellulose with trisaccharide branches Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  73 Xanthan Forms highly viscous solutions at very low concentrations, as low as 0.01% depending on the formulation very stiff chains with very limited capacity to fold when in solution Is used as a stabiliser in emulsions (e.g., mayonnaise, salad dressings etc.) or gluten-free formulations in bakery products but not very good in stretch behavior Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  74 Chitin N-acetylglucosamine linked via β-(1 → 4) bonds, is an amide and acetylated derivative of glucose the primary component of cell walls in the exoskeletons of arthropods, such as crustaceans (e.g., shrimp shells, squid pen) and insects Deacetylation of chitin in alkaline environments results in chitosan, which is the only positively charged polysaccharide Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  75 Chitin ***Chitin and chitosan are in the group of polysaccharides known as GAGS (glycosaminoglycans) Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  76 Dietary Fiber (DF) Classified based on their ability to ferment in the large intestine or their solubility in aqueous buffers not hydrolysed by the endogenous enzymes in the small intestine in humans and have beneficial health effects cellulose, hemicellulose, pectin, resistant starch, and lignin are DFs hemicelluloses → heteropolysaccharides Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45  77 Dietary Fiber (DF) Based on their solubility Soluble dietary fiber (SDF) Insoluble dietary fiber (IDF) increase viscosity of the formulation have limited capacity to enhance viscosity Kontogiorgos, V. (2021). Introduction to food chemistry. Springer Nature. pp 19-45 78  79 SUMMARY Only monosaccharides can pass through the small intestinal wall into the blood stream, Human digestive enzymes can only hydrolyze sucrose, lactose, starch, and starch-based oligosaccharides to monosaccharides (d-glucose, d-fructose, and d-galactose) DFs are nondigestible → increased fecal bulk, decreased stool transit time, and reduced serum cholesterol levels. Some forms of starch, known as resistant starch, can reach the colon in undigested form and serve as a prebiotic substrate for beneficial microflora.  80 Next Topic… 2.3 Proteins  81 References  82 Any questions? Contact information: Office hour: [email protected] Ezgi Pulatsu, PhD Tue 12.00-1.00 pm (Teams-online, the link is on [email protected] [email protected] Brightspace) Or By Appointment