Raw material selection: dairy ingredients 45 2. 6.4 Butter The domestic use of butter is well known, but as an industrial ingredient used chilled foods manufacture it finds application in soups and sauces. It is a constituent of roux, along with flour, used in the preparation of sauces. Garlic butters and herb butters are used as garnishes in chilled ready meals and savour ishes, fillings for garlic bread and as toppings for cooked meats, e.g., steak, chicken and fish. The production of sweet-cream butter involves inducing phase inversion of the oil-in-water emulsion of cream to create a water-in-oil mulsion, or butter. A number of methods exist, as reviewed by Lane(1998).A commonly used method is the fritz and senn method, which involves rapidly cooling 42% fat cream to 8C and holding for 2 hours, then raising the temperature to 20-21C for 2 hours and cooling to 16C, or the churning temperature. The tempering process reduces the level of mixed fat crystals in the milkfat globules, ensuring that the high melting point triacylglycerols crystallise s pure fat crystals. This improves the spreadability of the butter, particularly when the milkfat has a low iodine value and it is hard Tempered cream is processed in a continuous buttermaker with four sections the churning cylinder beats the cream and causes the milkfat globule membrane to rupture, whereupon the fat crystals coalesce, the separation section drains buttermilk from the butter; the squeeze-drying section expels remaining buttermilk; the working section smooths the product. In the production of salted butter, salt is added in the working section. It dissolves in the aqueous, discontinuous phase of butter, and at a rate of 1. 6-2.0% results in a salt-in-water content of around 11%- sufficient to inhibit microbial activity. Microbial activity is not the sole cause of quality deterioration in butter. Evaporation causing surface colour faults and the development of oxidative rancidity causee by exposure to light are cited as possible problems(Richards 1982). Market butter is packed in tubs or foil which exclude light and possess high moisture arrier properties. Butter as an industrial ingredient is supplied in 25kg units packed in corrugated fibreboard cases lined with polyethylene film. Lactic butter may be made by the fermentation of cream with lactic acid bacteria, though the flavour of cultured butter may be replicated by the addition of certain pounds to sweet cream used for butter making(Nursten 1997). Garlic and herb butters are made by blending butter with the relevant ingredient and extruding to produce the required portion shape and size 2.6.5 Skimmed milk concentrate and skimmed milk powder Skimmed milk concentrate and skimmed milk powder find application in custards, toppings, soups, sauces, dips and desserts. Skimmed milk is the by roduct of cream separation and contains around 91% water. The skimmed milk solids are the milk proteins, lactose and minerals, with a trace of fat. Skimmed milk concentrates are made by vacuum evaporation and products of 35-40% total solids are common for bulk supply to food manufacturers. Higher solids levels give rise to problems of viscosity, age gelation and lactose crystallisation2.6.4 Butter The domestic use of butter is well known, but as an industrial ingredient used in chilled foods manufacture it finds application in soups and sauces. It is a constituent of roux, along with flour, used in the preparation of sauces. Garlic butters and herb butters are used as garnishes in chilled ready meals and savoury dishes, fillings for garlic bread and as toppings for cooked meats, e.g., steak, chicken and fish. The production of sweet-cream butter involves inducing phase inversion of the oil-in-water emulsion of cream to create a water-in-oil emulsion, or butter. A number of methods exist, as reviewed by Lane (1998). A commonly used method is the Fritz and Senn method, which involves rapidly cooling 42% fat cream to 8ºC and holding for 2 hours, then raising the temperature to 20–21ºC for 2 hours and cooling to 16ºC, or the churning temperature. The tempering process reduces the level of mixed fat crystals in the milkfat globules, ensuring that the high melting point triacylglycerols crystallise as pure fat crystals. This improves the spreadability of the butter, particularly when the milkfat has a low iodine value and it is hard. Tempered cream is processed in a continuous buttermaker with four sections: the churning cylinder beats the cream and causes the milkfat globule membrane to rupture, whereupon the fat crystals coalesce; the separation section drains buttermilk from the butter; the squeeze-drying section expels remaining buttermilk; the working section smooths the product. In the production of salted butter, salt is added in the working section. It dissolves in the aqueous, or discontinuous phase of butter, and at a rate of 1.6–2.0% results in a salt-in-water content of around 11% – sufficient to inhibit microbial activity. Microbial activity is not the sole cause of quality deterioration in butter. Evaporation causing surface colour faults and the development of oxidative rancidity caused by exposure to light are cited as possible problems (Richards 1982). Market butter is packed in tubs or foil which exclude light and possess high moisture barrier properties. Butter as an industrial ingredient is supplied in 25kg units, packed in corrugated fibreboard cases lined with polyethylene film. Lactic butter may be made by the fermentation of cream with lactic acid bacteria, though the flavour of cultured butter may be replicated by the addition of certain compounds to sweet cream used for butter making (Nursten 1997). Garlic and herb butters are made by blending butter with the relevant ingredient and extruding to produce the required portion shape and size. 2.6.5 Skimmed milk concentrate and skimmed milk powder Skimmed milk concentrate and skimmed milk powder find application in custards, toppings, soups, sauces, dips and desserts. Skimmed milk is the by￾product of cream separation and contains around 91% water. The skimmed milk solids are the milk proteins, lactose and minerals, with a trace of fat. Skimmed milk concentrates are made by vacuum evaporation and products of 35–40% total solids are common for bulk supply to food manufacturers. Higher solids levels give rise to problems of viscosity, age gelation and lactose crystallisation. Raw material selection: dairy ingredients 45