Ice cream is a delicious, wholesome, nutritious frozen dairy product. It has higher nutritive, biological and caloric value. Consumer acceptance of ice cream depends largely on its structure, textural quality, resistance to melting and flavor. Ice milk is a term used in the USA to refer to a standardized frozen dessert class with a fat content between 2 and 8% (Tharp and Young, 2013). In Egypt and according to the Egyptian Standard 1185-3/2005, the fat content of ice milk must not less than 3%. Anhydrous milk fat can be partially or totally replaced by plant oils.
Stabilizers are one such ingredient, which, in spite of the low level in the formulation, impart specific and important functions to the finished product. The basic role of a stabilizer is to reduce the amount of free water in the ice cream mix by binding it as “water of hydration”, or by immobilizing it within a gel structure. Also it is the ability to absorb and hold large amounts of bound water, which produces good body, smooth texture, slow melt down and heat shock in the resultant product (Keeney, 1982; Goff, 1997).
In ice cream manufacturing, it is always difficult to get all the properties of ice cream using a single stabilizer. Today Dairy/Food Technologists have found a new technique of blending these stabilizers in different proportions to get excellent properties (Naresh and Merchant, 2006). Gelatin is a translucent, colorless, brittle (when dry), flavorless solid substance, derived from collagen obtained from various animal by-products. It is commonly used as a gelling agent in food. The use of gelatin as a stabilizer produces thin mixes that require a long aging period. Gelatin disperses easily and does not cause wheying off or foaming (Kilara and Chandan, 2008).
Carrageenans are a family of linear sulfated polysaccharides that are extracted from edible seaweeds. They are widely used in the food industry for their gelling, thickening and stabilizing properties. Their main application in dairy and meat products, due to their strong binding to food proteins. There are three main varieties of carrageenan, which differ in their degree of sulfation (kappa, iota and lambda). Carrageenan is used in many stabilizer blends at levels of 0.01 – 0.02% to prevent phase separation (wheying off) through interaction with milk protein (Kilara and Chandan, 2008).
Konjac flour, a neutral polysaccharide from the tuber of Amorphophallus konjac C. Koch. and A. oncophallus, is composed of D-glucose and D-mannose joined by β-glycosidic linkage (Imeson, 2010). Konjac flour is generally recognized as safe (GRAS) which has special properties as thickening, gelling, texturizing and water binding. It lowers cholesterol without any adverse effects and can be three times as effective as other polymers (Vuksan et al., 2000). Also it is synergistic with stanols and sterols for low-density lipoprotein (LDL) reduction (Yashida et al., 2006).
Emulsifiers added to ice cream have several important functions such as reduced whipping time, controlled fat destabilization, enhanced smoothness of texture, increased resistance to melting and shrinkage, and improved dryness (Arbuckle, 1986, Marshall and Arbuckle, 1996). Usually, blends of stabilizer and emulsifier designed to function best in full fat, low fat, or nonfat ice creams are used. The purpose of this study was to improve the quality attributes of ice milk using different blends of Konjac flour, k-carrageenan and emulsifiers.