Kappa-carrageenan, a widely used food ingredient, could form spherical microgels with an average diameter of 25 micrometers, report scientists from the School of Agriculture, Food Science and Veterinary Medicine at University College Dublin.
“The small size of these microgels offers good opportunities for their inclusion into food systems without causing settling or detrimental mouth feel attributes,” wrote the researchers, led by Jean-Christophe Jacquier in the Journal of Food Engineering.
“They also have the added advantage of using equipment available in most food companies such as a rotor-stator homogenizer, therefore making them a viable option to food manufacturers.”
Fat replacers, along with emulsion stabilizers, thickeners, suspending agents, gelling agents, fiber sources, and mouthfeel improvers all come under the umbrella of hydrocolloids. This market has grown significantly in the past 20 years in parallel with an increasingly complex food processing industry.
The delivery of bioactive ingredients, like vitamins and minerals, is also a growing area as food manufacturers seek to add value to the products and differentiate them for consumers who are increasingly health savvy.
Study details
The Irish researchers manufactured kappa-carrageenan (Gelcarin GP-911, FMC Biopolymer) microgels by emulsification with rapeseed oil (Millbrook Foods, Ireland).
“In order to obtain small and spherical microgels which would not adversely affect the overall mouthfeel or sensory properties of a food product, a special procedure was optimised based on the emulsification of the kappa-carrageenan solution in hot rapeseed oil using a high shear rotor-stator mixer, without the aid of surfactants, followed by fast tempering of the emulsion under mild agitation,” explained the researchers.
Optimal conditions were identified as a solution containing 4 per cent kappa-carrageenan at a temperature of 68 degrees Celsius, and a mixing speed of 3000 rpm in the high shear rotor-stator mixer.
According to the researchers, the microgels could offer a “broad range of functionalities such as nutraceutical delivery systems or fat replacers”.
Carrageenan concerns
According to Leatherhead Food International, carrageenan is used mainly in dairy products (milks, creams and desserts), jellies, ham and chicken products, and bakery glazes; agar is used as a gelling agent in a range of products, including jams, confectionery goods, meats and noodles; and the broader category of alginates are used in bakery creams, glazes and fillings, ice creams, jams, and some beverages.
Shortages in supply of the raw material have been driving up prices, with some having reached record prices. At the IFT meeting in Anaheim, CA last year hydrocolloid watcher Dennis Seisun from IMR International told FoodNavigator that the price of carrageenan had made progress back towards normal levels after a period of marked shortages – but indications at that time were that the price was inching back up again.
Source: Journal of Food Engineering
Volume 94, Issues 3-4, Pages 316-320
“Manufacture of food grade κ-carrageenan microspheres”
Authors: A. Ellis, J.C. Jacquier