Ice-cream

Organic ice cream remains a small proportion of the dairy market. With many upmarket ice creams available for consumers, organic ice cream must be of a premium quality. Ice cream in its basic form is milk, cream, sugar and flavour. Premium ice creams contain many novelties, from ribbons of caramel to chunks of fruit, and conventional ice cream manufacturers use many emulsifiers (which are prohibited in organic production) to create a smooth texture. 

Sauce bearnaise, for example, is an O/W emulsion that is mainly stabUized by egg yolk protein in an aqueous phase of low pH. Perram et al. [44] describe how this system is primarily stabihzed by electrostatic repulsive forces and show how DLVO theory can be used to describe the effects of pH, surface charge, ionic strength and temperature on the stability of this emulsion. 

Ice cream is partially frozen foam that is also an emulsion and a suspension, containing many components including proteins, fat, water and air. A typical ice cream mix might contain milk fat (10-16%), milk sohds-not-fat (9-12%), sugars (9-12%), corn-syrup solids (4-6%), stabilizers and emulsifiers (0-0.5%) and water [11, 15, 25]. When prepared, ice cream may have an overrun (Section 13.3) of 70-100% (that is, it will contain 40- 50vol% air) [11] (see Table 13.2). Due to the partial freezing, ice cream also contains dispersed ice particles. At —11 C, ice cream has a viscosity of about 10 mPa s [38]. 

5) Milk solids-not-fat (msn comprise lactose, casein micelles, whey proteins, minerals, vitamins, acids and enzymes derived from milk. 

Ice cream stabilizers (such as guar, carboxymethyl cellulose, xanthan) are used to produce smoothness in body and texture, reduce ice and lactose crystal growth during storage, provide product uniformity and resist melting [15,47]. Freezing is usually done at a temperature of about -7 °C, with about 75% of the water being turned to ice [38]. 

The second stage in ice cream production is foaming and emulsion destabilization. This is analogous to the foaming step in whipped cream [14, 48]. Air is incorporated by whipping or by air injection. Egg white acts as a foaming agent. 

---

Ice cream imitation Iceland spar Ice milk Ice removal... 

The most difficult property of fat to replace is flavor. Great expenditure of effort has gone into producing a tme butter flavor as flavor boosters in nondairy fat products and in dairy products including milk, cream, butter, and ice cream. Results have led to a successful dupHcation of buttery flavors which closely match the intended target. 

There is more activity in dairy products than anywhere else in the food industry. Ice milk and fro2en yogurt, early leaders in the field, rose rapidly in sales then plummeted. Fat-free ice cream has been marketed, but final results are not yet available. Sales of these products have not cannibalized traditional ice cream (35). Standards for traditional ice cream call for a minimum of 10% butterfat. One fat-free ice cream product is prepared from nonfat milk (skim) and cellulose gum. Fat-free ice creams have encountered strong resistance in some segments of the retail trade. Retailers in Maine and New York, states with important dairy producing industries, refuse to sell such products (36). 

Many essential oils are used for flavoting and perfumery, eg, neroH, geranium, and ylang (see Oils, essential). The whole fmit, cmshed fmit, and puree may be used directly in foods, ice cream, cakes, and confections. Fmit juices, concentrates, and essences are more commonly employed (see Fruit juices). 

Applications for synthetic character impact items include cough drops, toothpaste, chewing gum, candies, soft drinks, baked goods, gelatin deserts, ice cream, margarine, and cheese. 

A large portion of beans go to make extracts and tinctures, which are then used for ice cream, bakery goods, Hqueurs, and many other items. 

Emulsifiers are classified by the hydrophilic—lipophilic balance (HLB) system. This system indicates whether an emulsifier is more soluble in water or oil, and for which type of emulsion (water-in-oil or oil-in-water) it is best suited. Emulsifiers having alow HLB value are more oil soluble, and are better suited for water-in-oil appHcations such as margarine. Conversely, emulsifiers having a high HLB value are more water soluble, and function more effectively in oil-in-water emulsions such as ice cream (34). The use of this system is somewhat limited because the properties of emulsifiers are modified by the presence of other ingredients and different combinations of emulsifiers are needed to achieve a desired effect. The HLB values of some common emulsifiers are given (35). 

Lecithin. Lecithin [8002-43-5] (qv) is a mixture of fat-like compounds that includes phosphatidyl choline, phosphatidyl ethanolamines, inositol phosphatides, and other compounds (37). Commercial lecithin was originally obtained from egg yolks, but is now extracted from soybean oil. Lecithin is used in many products, including margarine, chocolate, ice cream, cake batter, and bread. 

Sorhita.n nd Sorbitol Esters. This group of emulsifiers is formed from the reaction of sorbitan and stearic acid. Sorbitan monostearate is often used in combination with polysorbate in ice cream, imitation dairy products, and baking appHcations (36). 

Ammonium glycyrrhizinate [53956-04-0] (AG), C42H N02g, is a flavor enhancer derived from Hcorice root. It is approximately 50 times sweeter than sucrose and is often used to enhance sweetness in a wide variety of food products (56). Maltol [118-71 -8] C H O, and ethyl maltol [4940-11-8], CyHgO, are used as flavor enhancers in products such as cake mixes, confections, cookies, ice cream, fmit juices, puddings, and beverages (57). 

Locust Bean Gum. Locust bean gum [9000-40-2], also known as catob seed gum, is a galactomannan extracted from the endosperm of the catob tree seed which is cultivated in the Mediterranean area. The primary use of locust bean gum is in dairy appHcations such as ice cream. It is often used in conjunction with carrageenan because the chemical stmctures of the two enable them to cross-link and form a gel (85). 

Cheese products generally must be maintained under refrigeration using closed flexible plastic, or plastic cups or tubs for packaging. Ice cream packaging is generally minimal, ie, lacquered or polyethylene extmsion-coated paper-board cartons, molded plastic tubs, or spinal wound composite paperboard tubs or cartons. 

Insert injection mol ding is used to manufacture snap closures for yogurt and ice cream cups and tubs and for breakfast cereal cans. In insert injection mol ding, a die-cut printed paperboard or other flat material is placed in the mold. The plastic is extmded around the insert to form a precision skeletal stmcture. 

In the food industry, guar gum is appHed as a stabilizer in ice cream and frozen desserts (58), and it is also used as a stabilizer for salad dressings, sauces, frozen foods, and pet foods. 

In the food industry, locust bean gum is used as a stabilizer in ice cream and in the preparation of processed cheese and extmded meat products. It is also used as an emulsifier and stabilizer of dressings and sauces and overall has similar properties to those outiined for guar gum. 

The worldwide uses of lecithin break down as follows margarine, 25—30% baking/chocolate and ice cream, 25—30% technical products, 10—20% cosmetics, 3—5% and pharmaceuticals, 3%. 

Pasteurization may be carried out by batch- or continuous-flow processes. In the batch process, each particle of milk must be heated to at least 63°C and held continuously at this temperature for at least 30 min. In the continuous process, milk is heated to at least 72°C for at least 15 s ia what is known as high temperature—short time (HTST) pasteurization, the primary method used for fluid milk. For milk products having a fat content above that of milk or that contain added sweeteners, 66°C is requited for the batch process and 75°C for the HTST process. For either method, foUowiag pasteurization the product should be cooled quickly to <7.2° C. Time—temperature relationships have been estabHshed for other products including ice cream mix, which is heated to 78°C for 15 s, and eggnog, which must be pasteurized at 69°C for 30 min or 80°C for 25 s. 

In the United States, 62% of fluid milk production is used for manufactured products, mainly cheese, evaporated and sweetened condensed milk, nonfat dry milk, and ice cream. Evaporated and condensed milk and dry milk are made from milk only other ingredients are added to make ice cream and sweetened condensed milk. 

Large quantities of evaporated milk are used to manufacture ice cream, bakery products, and confectionery products (see Bakery processes and LEAVENING agents). When used for manufacturing other foods, evaporated milk is not sterilized, but placed in bulk containers, refrigerated, and used fresh. This product is caHed condensed milk. Skimmed milk may be used as a feedstock to produce evaporated skimmed milk. The moisture content of other Hquid milk products can be reduced by evaporation to produce condensed whey, condensed buttermilk, and concentrated sour milk. 

Frozen Desserts. Ice cream is the principal frozen dessert produced in the United States. It is known as the American dessert and was first sold in New York City in 1777. Frozen yogurt is also gaining in acceptance as a dessert. The composition of various frozen desserts is given in Table 19. 

Ice Crea.m, Ice cream is a frozen food dessert prepared from a mixture of dairy iugredients (16—35%), sweeteners (13—20%), stabilizers, emulsifiers, flavoriug, and fmits and nuts (qv). Ice cream has 10—20% milk fat and 8—15% nonfat solids with 38.3% (36—43%) total soHds. These iugredients can be varied, but the dairy ingredient soHds must total 20%. The dairy iugredients are milk or cream, and milk fat suppHed by milk, cream butter, or butter oil, as well as SNF suppHed by condensed whole or nonfat milk or dry milk. The quantities of these products are specified by standards. The milk fat provides the characteristic texture and body iu ice cream. Sweeteners are a blend of cane or beet sugar and com symp soHds. The quantity of these vary depending on the sweetness desired and the cost. 

Preceded by a blending operatiou and pasteurization, the iugredients are mixed iu a freezer that whips the mix to iucorporate air and freezes a portion of the water. Freezers may be of a batch or contiuuous type. Commercial ice cream is produced mosdy iu coutiuuous operatiou. 

The iucorporatiou of air decreases the deusity and improves the consistency. If one-half of the final volume is occupied by air, the ice cream is said to have 100% overmn, and 4 L will have a weight of 2.17 kg. Ice cream from the freezer is at ca —5.5°C with one-half of the water frozen, preferably iu... 

Containerized ice cream is hardened on a stationary or continuous refrigerated plate-contact hardener or by convection air blast as the product is carried on a conveyor or through a tunnel. Air temperatures for hardening are —40 to —50° C. The temperature at the center of the container as well as the storage temperature should be <—26°C. Approximately one-half of the heat is removed at the freezer and the remainder in the hardening process. 

Other Frozen Desserts. Although ice cream is by far the most important frozen dessert, other frozen desserts such as frozen yogurt, ice milk, sherbet, and meUorine-type products are also popular. The consumption of frozen yogurt has been increasing rapidly. 

Ice milk is a frozen product which has less fat (2—7%) and slightly more nonfat milk soHds than ice cream. Stabilizers and emulsifiers are added. About half of ice milk produced is made as a soft-serve dessert, produced in freezers with an overmn of 40—100%. 

---