A qualitative method for gel strength assessment of phycocolloid-based gels

Seaweeds are the natural, sustainable, source for phycocolloids. Phycocolloids such as agar and agarose, carrageenan and alginate have many usages in a variety of industries including health, science, food, and cosmetics. The commercial application of each phycocolloid, and its commercial value, depend on its chemical/physical properties. One of the unique characteristics of certain phycocolloids is their ability to form gels. Gel properties such as gel strength, gel setting and melting temperatures vary between different seaweed species and among a single species, can vary depending on their growth conditions. Thus, measuring gels properties including gel strength is important for seaweed growers and scientist. State of the art gel strength measurements mainly includes the use of texture analyzers. However, such instruments are not always available for growers and scientists, and alternative methods for obtaining gels strength are desired. In this work we describe a home-made apparatus for assessing gel strength, or gel break point, of phycocolloid gels. The system measures the weight of water in a column required for breakage and penetration of a flat tip, pressed against gels at a concentration range of 0.5–1.5%. We found that the system gave repeatable results, both across different sampling trials, as well as across different users. The variation in the measurement was similar to that reported for other gel strength measuring devices. We propose the use of our system as a simple, flexible, and affordable method for quickly assessing gel quality of phycocolloid samples.