Principle of Food Science and Processing 2024 Lecture 8 PDF

Sugars and Fats 7 lecture Dr. Mohamed Elsaadany  Outline Sugars sources and roles in food products Nonenzymatic browning Types of Sugars and Sugar Syrups Properties of Sugars Sugar substitutes Baked Products Common ingredients in...

Sugars and Fats 7 lecture Dr. Mohamed Elsaadany  Outline Sugars sources and roles in food products Nonenzymatic browning Types of Sugars and Sugar Syrups Properties of Sugars Sugar substitutes Baked Products Common ingredients in baking Fats Properties of Fats and Oils Rancidity Dr. Mohamed Elsaadany 2 1 Sugars Dr. Mohamed Elsaadany 3  Sugars Sources of Sugar: Table sugar comes from two sources: Sugar beet Sugar cane Roles of Sugar in Food Systems: Sweetness, Tenderness, and Browning Acts as a separating agent to prevent lump formation in starch- thickened Sauces Reduces starch gelatinization Stabilizes egg white foams Raises the coagulation temperature of protein mixtures Adds bulk and body to foods such as yogurt Helps aerate batters and dough Reduces gluten structure by competing with gliadin and glutenin for water, thus, increasing tenderness Acts as the substrate that ferments to yield CO2 and alcohol Adds moisture retention properties to baked products Slows/prevents crystallization in candies if invert sugar is used 4 Dr. Mohamed Elsaadany 4 4  Roles of Sugar in Food Sweetness beverages Tenderness A batter/dough formula with sugar is more tender than one without sugar, because sugar binds with each of the two proteins gliadin and glutenin and absorbs water so they do not form gluten Browning Browning in some varieties of fruits and vegetables is due to enzymatic, or oxidative browning Two types of nonenzymatic browning including (1) The low-temperature Maillard browning reaction and (2) High-temperature caramelization 5 Dr. Mohamed Elsaadany 5 5  Nonenzymatic browning Maillard browning Involves the reaction of the carbonyl group of a reducing sugar with the amine group of an amino acid and occurs with: Low-temperature heat, a Maillard browning is responsible for the color changes that occur in many baked breads, cakes, and pie crusts, canned milks, meats, as well as candies Caramelization: Occurs in sugars heated to high temperatures (above its melting point [338 F (170 C), and the sugar ring (either pyranose or furanose) opens and loses The sugar becomes brown, more concentrated, and develops a caramel Caramel 6 Dr. Mohamed Elsaadany 6 6  Types of Sugars and Sugar Syrups Brown sugar. Brown sugar has a molasses film on the sugar crystals, it contains approximately 2 % moisture Confectioners’ sugar(confectionery sugar) is also known as powdered sugar and is derived from either sugar cane or sugar beet Confectioners’ sugar typically contains 3 Invert sugar. Invert sugar is created when sucrose is treated by acid or enzyme to form an It is more soluble and sweeter than sucrose and is commonly used in confections, Raw sugar. It is not approved by the FDA for sale in the United States since impurities and 7 Dr. Mohamed Elsaadany 7 7  Syrups (Liquids) The conversion of starch yields dextrose (glucose) and measured as 36–55 Corn syrup: Corn syrup is a mixture of carbohydrates (glucose, maltose, and other oligosaccharides) formed from the hydrolysis of cornstarch by using Corn syrup, due to its high glucose content, more readily participates in High-fructose corn syrup (HFCS): HFCS is a specialty syrup and contains approximately 42 % fructose, used in many beverages Honey: Honey is made from the nectar of various flowers and therefore, It contains approximately 20 % water and a mixture that is glucose and fructose (predominantly the latter), with no more than 8%sucrose 8 Dr. Mohamed Elsaadany 8 8  Syrups (Liquids) Maple syrup: The sap is boiled and evaporated, and the final product contains no more than 35 % water Molasses: Molasses is the syrup (plant juice) separated from raw sugar beet or sugar cane during its processing into sucrose, and it is a by- 9 Dr. Mohamed Elsaadany 9 9  Properties of Sugars Solubility Sucrose is more soluble than glucose and less soluble than fructose At room temperature, water is capable of dissolving sucrose in a ratio of 2:1 (67 % sucrose and 33 Elevation of Boiling Point The boiling point of sugar elevates with increasing concentrations of sucrose in Hygroscopicity However, other sugars that are high in fructose, such as invert sugar, HFCS, honey, Fermentable Occurs by biological process in which bacteria, mold, yeast, and enzymes anaerobically convert complex organic substances, such as sucrose, glucose, 10 10 Dr. Mohamed Elsaadany 10  Properties of Sugars Body and Mouth feel Sugars contribute body and “mouthfeel” words, the addition of sugar makes a food more viscous or gives If sugar is replaced by a non-nutritive or high intensity sweetener such as aspartame or saccharin, the consistency of 11 11 Dr. Mohamed Elsaadany 11  Sugar Substitutes Sugar substitutes include two categories: Artificial (or high-intensity) Sweeteners (noncaloric, nonnutritive) Sugar substitutes are “generally recognized as safe”(GRAS) Artificial sweeteners Acesulfame K. It is 200 times sweeter than sucrose and its not metabolized in the body; Its heat stable, used for baking and cooking purposes The acceptable daily intake of acesulfame potassium is listed as 15 mg/kg/day Aspartame. Aspartame is a nutritive sweetener that contains the same number of calories per gram as sugar (4 cal The upper limit of safety for aspartame = 40-50mg/Kg Note: Phenylalanine. Not advise for those with the genetic disease phenylketonuria (PKU) because the phenylalanine 12 12 Dr. Mohamed Elsaadany 12  Sugar Substitutes Saccharin. 300–700 The ruling required that foods containing saccharin must be labeled to read as follows: Use of this product may be hazardous to your health Saccharin is often used in baked goods, jams, jelly, chewing gum, canned fruit, candy, dessert toppings, and salad Cyclamate. it is still used as a sweetener, but does not approve by FDA Sugar alcohols (caloric, nutritive). Sorbitol( Mannitol ( Xylitol ( Novel Sweeteners (Stevia) It is a white powder composed of one or more intensely sweet glycosides derived from the leaves of a stevia (Stevia rebaudiana) and used as noncaloric sweetener 13 13 Dr. Mohamed Elsaadany 13