Texturising of Fermented Milk Products FROM RESEARCH & DEVELOPMENT

Transcription

1 Texturising of Fermented Milk Products FROM RESEARCH & DEVELOPMENT

2 TEXTURISING of Fermented Milk Products Set yoghurts, stirred or layered fruit yoghurts, curd cheese and buttermilk desserts with their undisputedly fresh and healthy image have always been very popular with the consumer. Fermented milk, the so-called "white mass", a protein gel, is an integral part of all of these products. In the past years, virtually boundless combination possibilities with fruit, pastry or also functional components, in conjunction with optimised manufacturing technologies have resulted in innovative additions to product ranges in this field, such as the introduction of seasonal products or products aimed at specific target groups. This has strengthened and even expanded the market position of these products. The consumer has very high demands on fermented milk products. A typical taste, an appealing look as well as a very specific consistency are expected. Both the recipe and the manufacturing technology are extremely important for the quality of yoghurt or curd cheese products. During the fermentation of milk, the proteins undergo structural changes. Casein micelles agglomerate, forming a three-dimensional network, the characteristic acid gel. Constitution and stability of this gel structure greatly depend on the raw material used, the processing of the raw material, the fermentation and on the process. Subjecting the raw material to heat treatment or increasing the solids content of the milk by adding, for example, skimmed milk powder or whey proteins, has a positive effect on the gel structure. In stirred products, the process after fermentation has to ensure that a maximum of this structure is maintained in the form of viscosity. 2

3 Acid gels are relatively weak gels and have therefore a tendency to serum separation, the so-called syneresis. This impairs the transportability of the products. Syneresis may also occur during storage, especially at higher temperatures, due to the contraction of the acid gel. This increasingly occurs in low-fat and low-solublesolids products. Pectin is a heteropolysaccaride with partly esterified polygalacturonic acid as its main component and is mostly obtained from the raw materials apple pomace and citrus peel. One distinguishes between high methylester, low methylester and low methylester amidated pectins, all of which differ in their stabilising, gelling and thickening properties. In order to prevent or reduce the tendency to syneresis, the solids content of the milk can be increased. More interesting is stabilisation using a hydrocolloid, as besides reducing the tendency to syneresis adding a hydrocolloid may also enhance organoleptic properties, such as body, mouthfeel, firmness, creaminess and surface habit. To prevent syneresis in and to add texture to the white mass, starch, gelatine, agaragar and, ever increasingly, pectins are used. As a fruit component with a generally positive image, pectin has long been used as a stabilising agent in drinking yoghurt products. Here pectin acts as a protective colloid inhibiting protein agglomeration and protecting the proteins towards dehydration and sedimentation during thermisation. Also by texturising of fermented milk products, pectins have the benefit of being a natural and thus consumer-friendly food additive that is also of economic interest on account of its low dosage. In the white mass application, pectin adds a smooth texture as well as surface gloss to the products and prevents or reduces serum separation during storage and transport. In this application, pectin is added as a stabilising agent before fermentation. The stabilising effect occurs as a result of a partial coating of the protein surface by the pectin, which contributes to the strengthening of the casein network and thus the solidification of the acid gel. 3

4 As watersoluble hydrocolloids, pectins also form strong hydrated zones resulting, on the one hand, in a creamy mouthfeel and, on the other hand, in a reduced tendency to syneresis. As pectin is added before fermentation, an optimum stabilisation dosage as recommended is of utmost importance in order to prevent the coagulation of the neutral milk (sweet coagulation), which would result in a grainy, unstable product. To meet the various demands made on yoghurt and curd cheese products Herbstreith & Fox has a whole range of pectin types on offer. In this application, low methylester and low methylester amidated pectins are used. Pectin Amid CM 020 and Pectin Classic AM 901 have been used for years in the stabilisation of the white mass: Pectin Amid CM 020 is an all-round pectin that is used in both set and stirred yoghurts. This pectin type reacts most flexibly and can be used with any type of yoghurt process control without a problem. The non-amidated Pectin Classic AM 901 is the first choice in organic products, often in combination with other hydrocolloids. Pectin Amid CM 025-A, a combination of specifically selected pectins, is recommended for the production of set yoghurts. Adding this pectin type at an optimum dosage yields a smooth and firm yoghurt gel. The tendency to syneresis, which increasingly occurs in low-fat and lowsoluble-solids products is significantly reduced. Pectin can completely or partially replace the milk powder, which is added to increase the solids content, and therefore contribute to cost reduction. The improved storage and transport stability of the products is a further benefit. Stirred yoghurts should have a creamy texture and should be able to be stirred easily and smoothly even at high viscosity. Pectin Amid CM 025, another specifically selected pectin, can help fulfil these requirements. A smooth and glossy surface, good structure and a low tendency to syneresis bestow on products made with this pectin an optimum appearance also over longer storage periods and provide them with stability during transport. The benefits of Pectin Amid CM 025-A may also be utilised for stirred yoghurts. Depending on recipe, technology and required effect in the final product the pectins are used in a dosage range of %. In addition to the above standard types, H&F has developed two new pectins that are custom-tailored to the varying demands on set and stirred yoghurts: Pectin Amid CM 025-A Pectin Amid CM 025 Mainly soy but also other vegetable proteins more and more are used as raw material in fermented products alternatively to milk proteins. To gain required product properties like firmness, viscosity etc. pectins there can be used as well. 4

5 PRODUCT OVERVIEW - H&F PECTINS Pectin Amid CM 020 amidated citrus pectin application in set and stirred fermented milk products increase of firmness and reduction of syneresis Pectin Amid CM 025 amidated citrus pectin preferred in stirred fermented milk products increase of viscosity and creaminess, smooth and glossy texture, reduction of syneresis Pectin Amid CM 025-A amidated citrus pectin preferred in set fermented milk products, but also benefits in stirred fermented milk products increase of firmness, smooth surface, smooth gel, reduction of syneresis Pectin Classic AM 901 apple pectin application in set and stirred fermented milk products, especially in organic products often in combination with other hydrocolloids increase of firmness, reduction of syneresis Furthermore, by the use of a combination with Herbacel AQ Plus Citrusfaser* a further increase of the stability can be achieved. Additionally, the white mass shows an extremely creamy texture and a pleasant mouthfeeling at a very low tendency to syneresis. With the use of Herbacel AQ Plus the product can additionally be called high-fibre if the dosage of fibres corresponds with the legal standards. *Herbacel AQ Plus Citrus Fibre is a product of Herbafood Ingredients GmbH, www. herbafood.com 5

6 Herbstreith & Fox KG Recipe Set and Stirred Yoghurt Product Pectin Amid CM g Pectin (= 0.12%) 30g skimmed milk powder 60g sucrose 909g whole milk yoghurt culture Input: approx. 1000g ph-value: approx. 4.6 Mix dry ingredients (pectin, skimmed milk powder and sugar) Stir mixture into cold milk (Ultra Turrax ) Leave to swell for 1 hour Heat solution to 85 C, 20 minutes Homogenise at 100 bar Leave to cool to C Add yoghurt culture, fill into containers Allow to ferment to a ph-value of Leave yoghurt to cool to 7 C In the manufacture of stirred yoghurt the yoghurt is being glazed after acidification and cooled to 20 C. Then the fruit preparation (20%) is mixed in the yoghurt before bottling. In set and stirred yoghurt pectins provide texture and prevent syneresis. Herbstreith & Fox offers pectins to stabilise fermented products like set or stirred yogurts, curd cheese or buttermilk desserts as well as soy yogurts and to give them their structure. These pectins offer the opportunity to the user to reach special product properties accordant to his demands and possibilities. RESEARCH AND DEVELOPMENT HERBSTREITH & FOX CORPORATE GROUP 24/01/2007 6