Lecture XVIII Charged PS’s - Carrageenan & Agar Fucellaran Lecture #18 - Charged PS’s - Carrageenan, Fucellaran, Agar (Seaweed PSs)

Marine Algae Classification Phaeophyceae (Brown algae) Rhodophyceae (Red algae) Genus Ascophyllum Laminaria Macrocystis Lessonia Durvillaea Eucheuma Gigartina Furcellaria Chondrus Gracilaria Gelidium Hydrocolloid Alginates Carrageenan Agar

Red Seaweed PSs Common structural features of Red Seaweed Galactans Complements of FMC Corp Common structural features of Red Seaweed Galactans

Red Seaweed PSs

Charged PS’s - Agar History Oriental cuisine A.K.A., Japanese isinglass, Chinese isinglass, Seaweed isinglass, Japanese gelatin, etc. Since 1882 1st seaweed extract used

Charged PS’s - Agar Manufacture/ Production Japanese Agar Diver Seaweed collection Sold as dried gel Production Extract - hot water Freeze-thaw Dry, grind, pack

Charged PS’s - Agar Structure (Agarose) CH2OH O OH O O O CH2 OH OH O n

UniqueProperties of Agar I Solubility - only > 85oC Viscosity Insoluble at R.T. “Kelated” agar hydrates at lower temps Very low vis at elevated temps

UniqueProperties of Agar II Solubility - only > 85oC Viscosity Very low vis at elevated temps Gelation Very strong gels at low conc. Hysteresis - set at 32 - 39oC - melt <85oC Brittle texture LBG increases gel strength

Major Food Applications of Agar Icings Glazes Piping jellies Japanese desserts & confections (Media pour plates) Regulatory Status - GRAS

Piping jelly used to write this…

Benefits vs other Hydrocolloids Strongest gelling agent/lowest conc Hysteresis - gel/setting points Low viscosity hot/high solids Liabilities vs other Hydrocolloids Sporadic Supply problems High Cost Insoluble cold

Charged PS’s - Carrageenans Background “Carrageenan” = family of PSs Chondrus crispis - NE shores of US & Canada a.k.a. “Irish Moss” Furcellaran - developed in Denmark - WW II a.k.a. “Danish Agar Furcellaria fastigiata - similar to kappa-Carr

Cross Section of Red Seaweed Carrageenan is located in the cell wall and intercellular matrix between the cellulosic fibers During manufacturing, carrageenan is extracted to achieve good solubility in applications Courtesy of FMC Corp

Carrageenan Extract Manufacturing Process Alcohol precipitation: Complete extract range Cold soluble grades KCl precipitation + freezing: Good dispersibility Good color A second extract range KCl precipitation + pressing: Very limited extract range Courtesy of FMC Corp

Repeating units of Main Carrageenan Types Kappa Gal-4-sulfate + 3, 6 AG OH CH2OH O3SO O CH2 CH2OH CH2 O3SO OH O OSO3 Iota Gal-4-sulfate + 3, 6 AG-2-sulfate Lambda Gal-2-sulfate + Gal-2,6-sulfate CH2OH HO O CH2OSO3 OH OSO3 Courtesy of FMC Corp

UniqueProperties of Carrageenan(s) General Properties Protein reactivity (complexation) Gelation Heat reversible, ion aided

Comparative Properties of Carrageenans Courtesy of FMC Corp

Gelation Mechanism of Carrageenan Cool Cool Heat Heat Double helix formed Gel Random coil Solution Aggregated double helices Hard gel Kappa - high temperatures - intermediate step - final gel Iota - high temperatures - final gel - Lambda - all temperatures - - Courtesy of FMC Corp

Change in Comformation of Carrageenan Molecules -SO3 here produces kinks in chain Change in Comformation of Carrageenan Molecules -SO3 here prevents helix formation completely Courtesy of FMC Corp

Texture of Carrageenan Gels 2% Kappa carrageenan 2% Iota carrageenan Courtesy of FMC Corp

Combinations of Kappa & Iota Carrageenan Are Used to Obtain a Desired Texture Fracture Points 50/50 Blend Increasing Strength Iota Carrageenan Increasing Elasticity Courtesy of FMC Corp

k-Carrageenan Galactomannan Synergism Complements of FMC Corp

Interaction of protein-Carrageenan Molecules Decreasing pH > pI --> at pI --> Interaction of protein-Carrageenan Molecules < pI --> < pI --> Courtesy of FMC Corp

Interaction of protein-Carrageenan Molecules Stable Complex Ppt Ppt Interaction of protein-Carrageenan Molecules Courtesy of FMC Corp

Carrageenan Gelation in Milk, a 2-Step Process sol Step 1. At high temperatures, carrageenan reacts electrostatically with kappa casein Step 2. On cooling, carrageenan chains interact, creating a network Casein micelle with kappa casein on the surface Carrageenan chains Cooling

Complements of FMC Corp Carrageenan Milk Gels Kappa Lambda Iota All carrageenans have ‘milk reactivity’ Properties of gels vary considerably Complements of FMC Corp

Complements of FMC Corp

Complements of FMC Corp

Functions of Carrageenan in Chocolate Milk Carrageenan imparts suspension and body in chocolate milk due to both water gel and milk gel potential. Cocoa suspension is mainly due to carrageenan-carrageenan helix formation during cooling which forms a weak gel matrix, entrapping the cocoa particles. Carrageenan-Protein interactions account for the viscosity development, mouthfeel and body of the finished chocolate milk. Carrageenan is the only soluble hydrocolloid capable of permanently suspending cocoa in chocolate milk. Other gum/starch combinations will temporarily suspend cocoa due to viscosity effects. However, these blends impart a heavy body and may leave a gummy film on the tongue which coats flavor receptors.

Benefits vs other Hydrocolloids Protein reactivity Extremely efficient stabilizer in milk Heat reversible gelation Good clarity

Liabilities vs other Hydrocolloids Poor acid stability unless gelled Gels tend to be brittle and weep Undesired gelation w/ high protein Sporadic supply problems Regulatory Status - GRAS