03: Sweeteners for Food Industry-I
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Paper No.: 13 Paper Title: FOOD ADDITIVES Module – 03: SWEETENERS FOR FOOD INDUSTRY-I Sweeteners are food additives that are used to improve the taste of everyday foods. Natural sweeteners are sweet-tasting compounds with some nutritional value; the major ingredient of natural sweeteners is either mono- or disaccharides. Nutritive sweeteners include sucrose, high fructose corn syrup (HFCS), corn syrup, honey, fructose, molasses, and sugar alcohols such as sorbitol and xytilol. Artificial sweeteners, on the other hand, are compounds that have very little or no nutritional value. Application of sweeteners in food products Sweeteners have always been an important ingredient in food products viz., ice cream and frozen desserts, confectioneries; baked goods; jam, jellies and marmalades; toffees and candies, etc. In case of ice cream, the sweeteners comprise approximately 40 % of the total ice cream solids, 85% of Sherbets and over 95% of solids in ices. In toffees and candies, sucrose may comprise 65-85% of the solids in such products. Consumers satisfy their ‘sweet tooth’ with a variety of sweeteners. Sugar is also used as a preservative and aids in gelling in case of jams, jellies and marmalades. They provide body and texture and even add bulk in ice cream and baked goods, and it aids in fermentation in breads and pickles. Sweetener can act as a humectant in cakes (i.e. stops them from drying out). Sweeteners can strengthen the mouth feel in soft drinks. Sweeteners play a role in ice cream by lowering the freezing point. They are implicated in enhancing other flavor (i.e. salty). Confectionery products: The confectionery industry relies heavily on nutritive sweeteners for the many physical and chemical properties that they impart. The most commonly used sweeteners, sucrose, dextrose (glucose), and corn syrups, are fundamental in the production of confectionery items such as hard candy, caramel, taffy, chewing gum, chocolate, and gummed candies. Depending on the final confection, these sweeteners provide sweetness, mouth feel or body, graining or crystallization, texture, hardness or softness, shelf life, flavors, and colors. The sweeteners play a significant role through sugar crystallization in forming a confection's texture and contributing to its mouth feel. The wide variety of candies exists today because of the ways in which sugar can be manipulated in its crystalline form. The sugar crystals range in size from very fine to very coarse. Non-crystalline sugar solutions can harden into an amorphous state, referred to as a glass. For many confections, it is critical that sugar remain in non- crystalline state. In these candies, crystal formation, also referred to as graining, can result in cloudiness or loss of smoothness. Table 1 categorizes the candies as crystalline and non- crystalline types. Fructose is typically more soluble than sucrose and thus tends to remain in its non-crystalline phase, or syrup phase. Since honey is composed primarily of fructose and glucose, it is often used to retard sucrose crystallization in candies, as are corn syrups. Table 1. Candy classification based on crystalline nature of sweetener used Crystalline candies Non-crystalline candies Chocolates Hard candies Fudge Toffee Fondant Caramel Nougat Gummed candies Tablets Panned candies Marshmallows Traditional sweetened gelled or gummed candies contain about 75% sugar composed of 40–50% sucrose and 50–60% corn syrup. The sweeteners provide texture and sweetness and inhibit crystallization. Sucrose is the main sweetener in traditional chocolate products and its content can range from 35 to 50%. Ice cream and frozen desserts: Ice cream and frozen dessert is the only food category in which sweeteners have played a vital role. Ice cream and ice milk mix must have a freezing point high enough to allow adequate ice crystal production in standard ice cream freezers. Hence, when substituting sucrose, care must be exercised in controlling the freezing point (FP) of the mix. It is important to know the sweetening power and freezing point depression (FPD) factor of various sweeteners relative to sucrose. Sucrose is invariably used with some other sweeteners like corn syrup solids to attain smooth textured ice cream.‘Soft-scoop ice cream’ can be prepared using saccharides that have high FPD factor in the mix formulation; ice cream remains soft to be easily scooped out post hardening from the deep freeze cabinet. Relative sweetness is one of the first characteristics to be determined, when developing a new carbohydrate sweetener. Role played by sweeteners in food products The sweeteners used in frozen desserts perform various functions such as: Gives sweetness and thus palatability Balances the fattiness of the added fat Provides bulk and body – to improve mouth feel Controls ice crystallization and thereby helps to produce a smooth textured product, especially in frozen products like ice cream, Brings about suitable depression in the FP of the mixture, enabling the mix to be whipped and frozen simultaneously and thus afford the customer a delectable, refreshing food Enhances flavor of food product Improves the shelf life of the product Increases the energy content. Nutritive sweeteners The nutritive sweeteners provide same or fewer calories than sugar (sucrose). Examples of nutritive sweeteners are fructose; maltose; lactose; honey; polyols like sorbitol, xylitol, lactitol, mannitol, erythritol, isomalt, maltodextrin, polydextrose, hydrogenated starch hydrolysate, etc. Monosaccharides: The monosaccharides like glucose, fructose and galactose are composed of just one sugar molecule, and are known as the ‘simple sugars’. Glucose and fructose are abundant in fruits, honey, and processed foods. Galactose is found only in milk. Disaccharides: Disaccharides are formed from two simple sugar units that are chemically attached, and include sucrose, lactose and maltose. Sucrose comes from sugar beets or sugar cane, and is more commonly known as table sugar. Sucrose is composed of the two simple sugars, glucose and fructose. It is the most abundant sugar in nature, important for its palatability, availability, low cost, and simplicity of production. Additional products from the refinement process of sucrose are molasses, brown sugar, and confectioners’ sugar. Lactose is referred to as milk sugar. Lactose is made of the two simple sugars glucose and galactose. Maltose, two glucose units, is the result of the fermentation of the starch in grains by yeast or enzymes, as in bread-making or brewing. 1. Sucrose General characteristics: Sucrose is composed of glucose and fructose, and is primarily obtained from cane sugar and sugar beets. Sucrose is purified and granulated to various stages to provide raw, white, brown and powdered sugars. ucrose is highly soluble in water and its concentration in food is limited by its sweetening effect. It contributes to the calorific value of food (i.e. 4 k.cal./g). Sucrose is the most abundantly available sweetener and is used as a standard reference for sweeteners. Crystallization of sucrose during ice cream freezing can affect its texture and mouth feel. The sugarcane processing involves extraction of the cane juice by milling or diffusion, clarification of the juice, concentration of the juice to syrup by evaporation, crystallization of sugar from the syrup, and separation and drying of the crystals. Beet sugar factories generally produce only white sugar from sugar beets. Sugar is available in numerous forms. Dry, white cane products include powdered, multipurpose granulated and extra-large crystals (useful for slow dissolution). Liquid cane sugars, typically 67oBrix, offer easy storage and handling and provide mouth feel in soft drinks, creamy tones to dairy desserts and balanced flavor in sauces and vinegar-based products. Sucrose contributes important functionalities, such as browning and fermentation regulation in baked goods, bulk and rich texture in ice cream and jams, viscosity in beverages, and flavor enhancement in sweet and savory products. Sucrose has good solubility, controls crystallization and can improve shelf life. Advantages of using sucrose in food products Provides a sweet taste without secondary or after flavours. Less likely to contribute to heated flavours and burned colours (e.g. in ice cream) Provides body or mouth feel by increasing the viscosity of the product Acts as a flavor enhancer, when used at above or below the threshold levels of sweetness. Through exerting osmotic pressure at given sugar concentration, it can enhance the shelf life of food product by inhibiting spoilage microorganisms. Disadvantages in using sucrose in food products It is a contributor to dental caries Diabetic persons are advised to refrain from consuming sucrose in their diet Sucrose may crystallize in certain food products culminating in defects i.e. sucrose crystallization in jams, surface crustation in Sherbets, etc. 2. Invert Sugar General characteristics: It refers to sucrose hydrolysed by heat, acid solution or the enzyme invertase to constituent sugars i.e. 50% glucose and 50% fructose. A gain of 5% in solids is achieved depending on the degree of inversion. Hydrolysis of sucrose up to 50% using a combination of -galactosidase and -fructofuranosidase has been recommended for inclusion as a sweetener in food products including ice cream. Invert sugar is sweeter than granulated sugar, enhances flavor, resists crystallization and is a better humectant than sucrose. Typical uses include icings and fruit fillings for smooth