GELLAN GUM GEL

Gellan Gum Gel

Abstract

In the following study, the investigation of structural and mechanical properties of low acyl gellan gum gel in the existence of sodium chloride has been done by the use of large deformation compression experiments. The study concluded that the concentration of gellan gum varies from 0.6 to 1.2 weight %. Also, sodium chloride, as a cation, varies from 0.6 to 1.6 weight %. The calculations of stress at failure and strain at failure were completed by using the modulus of Young with the help of compression experiments. The samples of gellan gels were used for the cycling test for mimicking some oral processing. For this purpose, around 500 cycles were chosen and the load was recorded as 3.5 N, 10.5 N and 15 N for soft, medium and hard gels. The heights of samples were minimized after cycling test. As a result, water released from gels. There were changes made in the mechanical properties of the gellan gels because of the cyclic compression test. It was observed that cyclic compression made these gels harder and stronger than before. However, gels became more brittle after the cyclic compression when the Young's modulus was increased.

Table of Contents

1. Introduction1

Applications in Industry1

Properties of Gellan Gum3

2. Materials and Methods4

2.1. Gel Preparation4

2.2. Compression Tests5

2.3. Water Release5

2.4. Cyclic Compression Test6

3. Results and Discussion6

Conclusion11

Gellan Gum Gel

1. Introduction

Gellan gum is an extra cellular polysaccharide, which is produced by the bacterium Sphingomonas elodea. It is composed of repeating tetrasaccharide (1, 3-ß-D-glucose, 1, 4-ß-D-glucuronic acid, 1, 4-ß-D-glucose, 1, 4-a-L-rhamanose) units that contain one carboxyl side group. Gello gum functions as a polyelectrolyte because of its carboxyl groups on the repeat unit. It produces gels that are firm, hard and brittle. However, the properties are based on the ionic strength, cation, pH, and concentration of polymer and temperature (Moritaka, Nishinari, Taki &Fukuba, 1995; Sanderson 1990; Yamamoto & Cunha, 2007).

Applications in Industry

Gellan gum are used primarily in the food industry as a suspending agent, thickener, and stabilizer or as structuring of foods. It used in small doses; it acts as a suspending agent in liquids by adding a very small viscosity (Lau et al. 2000: 667). It can allow, for example, the uniform distribution of cocoa in milk chocolate or the strengthening agents, such as calcium or fibre, in all kinds of beverages. It does not alter the taste of food when it added to food products. The heat resistance of gellan gum to processed foods can provide more support to changes in temperature during transport and storage.

Gellan gums are additive of food, which act as thickening or gelling agents. They have the ability to develop gel textures in food products that range from hard plus brittle to fluid. There are various products that contain such gums including bakery fillings, dairy products, icings with glazes, confections, desserts, jams and jellies, spreads that are less fattening, foods that are microwaved, sauces, puddings, structured foods, and toppings (Ketz 1988: 532). Gellan gum is a substitute for starch in ...