fatty acids are produced by interesterification of glycerol and fat. The selection of fat determines the functional properties of the emulsifier. The mono- and diglycerides can be further esterified with organic acids. For instance lactic acid is used for formation of E472b lactic acid esters of mono- and diglycerides of fatty acids, so called lactic acid esters. Compared to mono-and diglycerides, lactic acid esters are more hydrophilic. Lactic acid esters are not commonly used in ice cream production. However, it has been found that it has a great influence on foam stability and texture when used in combination with monoand diglycerides. This fact can be utilised in production of ice cream with high overrun. Figure 1: 1-Monoglyceride (E471) Figure 2: Lactic acid esters of mono- and diglycerides of fatty acids (E472b) The main functions of the stabilizers are to: • • • • • • • increase the mix viscosity prevent whey separation (syneresis) improve the whipping properties improve the texture prevent ice crystal growth (during storage) improve the melting resistance regulate sensory properties Manufacturing ice cream with 150 - 185 % overrun The effect of stabilizers in an ice cream with high overrun As always in ice cream the emulsifiers for high overrun ice cream are used together with stabilizers. The stabilizers are hydrated and dispersed in water reducing the amount of free water in the ice cream mix. The stabilizers bind the water by means of hydrogen bonds or trap the water in a threedimensional network reducing the mobility of water resulting in an increased viscosity. The options when choosing stabilizers are far greater than in the case of emulsifiers. Most countries allow the use of a wide range of stabilizers. The most commonly used stabilizers in ice cream are: • • • • • guar gum (E412) locust bean gum (E410) cellulose gum (E466) alginate (E401) carrageenan (E407). Palsgaard recently carried out a project with the aim of creating a solution for production of ice cream with overrun as high as 150 – 185 %. The quality in terms of sensory attributes, melt-down properties and storage stability should be comparable to standard ice cream. Ice creams with fat levels from 6 – 10 % were included in the trials. Vegetable fat was used as fat source and whey powder and/or skim milk powder was used as milk solid non fat. The use of whey powder also meant that the protein level was low in the some of the trials. The ice cream was produced in Palsgaard’s pilot plant by means of a HTST unit combined with a continuous freezer. After hardening the ice creams were transferred to a storage freezer at -18°C. For evaluation of the storage stability heat-shock tests were carried out by increasing the temperature to -10°C for 4 days after which the ice creams were transferred back into the storage freezer. Figure 3. Guar gum, locust bean gum and alginate are often used as stabilizers in ice cream. Palsgaard Technical Paper - October 2011 Manufacturing high quality ice cream with high overrun 3
Del
Print
Download PDF fil
