Enzymatic gelation of sugar beet pectin in food products

Sugar beer pectin is a food ingredient with specific functional properties. It may form gels by an oxidative cross-linking of ferulic acid. In the pre sent study, the gel forming properties of three oxidative enzymes were exam ined in different food relevant conditions. The enzymes chosen were two lac cases and one peroxidase. The textural properties of the produced gels were measured on a texture analyser. The influence of sugar, salt and protein w ere analysed. Finally, the enzymatic gelation was studied in three food pro ducts with added sugar beet pectin. These were black currant juice, milk an d chopped heat-treated meat emulsion. The addition of salt resulted in softer, less stiff and chewy, and less adh esive gels. Generally speaking, sugar addition increased the hardness but a t high concentration the gels were very brittle. However, Young's modulus w as lower in gels containing sugar than in standard gels. Protein reduced th e hardness, stiffness and chewiness of the gels whereas there were some var iation in the effect of protein on the adhesiveness of the gels. Sugar beet pectin in black currant juice formed a gel and a gelation also took place in milk. In luncheon meat a cohesive gel was formed which bound the meat pi eces together thereby making the product sliceable. However, in two of the food products some unwanted side effects were observed. The enzymes did not only catalyse the cross-linking, but also oxidised the anthocyanins in the black currant juice and short chained fatty acids in milk. This caused a d iscoloration of the juice and the development of a strong off-flavour in th e milk. In luncheon meat no unwanted side effects are found. (C) 2000 Elsev ier Science Ltd. All rights reserved.