Structure-Function Relationships in Carrageenans and Agarose. Jana

Size: px

Start display at page:

Download "Structure-Function Relationships in Carrageenans and Agarose. Jana"

Erik Hines
5 years ago
Views:

1 Structure-Function Relationships in Carrageenans and Agarose Jana October 18, 2013

4 Polysaccharides

5 Polysaccharides Anti-Tumor

6 Polysaccharides

Polysaccharides Polysaccharides systematic study Source Molecular structure Assembly Solution Properties provides better insights about their structure-function relationships and guides in

7 Polysaccharides Polysaccharides systematic study Source Molecular structure Assembly Solution Properties provides better insights about their structure-function relationships and guides in their improved utility in food and non-food applications. Further, knowledge about their interactions with protein/virus molecules helps in the development of polysaccharide-based vaccines.

8 Why do we Need the Knowledge about Polysaccharides Structure-Function Relationships? Polysaccharides have extensive group of different chemical structures and exhibit a wide variety of unique molecular structures leading to sheets and spirals of single, double and triple helices. The structural forms, obtained in the solid state, appear to remain unaltered even in the hydrated environment of the polysaccharide solutions and gels. Hence, knowledge of polysaccharides three-dimensional structure, through fiber diffraction analysis, and rheological behavior of their solutions as well as their intrinsic relationships is very much necessary for their effective utilization in food and non-food applications.

9 Carrageenans

10 Carrageenans Fifteen Carrageenans : k, i, l, q, m, n,,,,,,,, and k, i, q,, and contain 3, 6-anhydro-bridge in the -D-galactose residue k, i, l, m and n are commonly found in most of the seaweed specimens

11 Carrageenans k-, i- and l-carrageenans are utilized extensively due to their greater versatility. They carry one, two and three sulfate groups, respectively, per disaccharide repeat. In the presence of mono and divalent cations, gelation occurs for k- and i-carrageenans, but l-carrageenan does not gel at any concentration. Gels of k-carrageenan are relatively hazy and brittle while i-carrageenan develops very clear and elastic gels that are free from syneresis. Therkelsen, G. H. In Industrial gums. Polysaccharides and their derivatives; Whistler, R. L.; BeMiller, J. N., Eds.; Academic Press: New York, 1993, ; Piculell, L. In Food polysaccharides and their applications; Stephen, A. M., Ed.; Marcel Dekker Inc.: New York, 1995, ; Stortz, C. A.; Cerezo, A. S. Curr. Top. Phytochem. 2000, 4,

12 Carrageenans Food: Bathroom: Medicine: Pet food: Other: Instant and cooked pudding, whipped cream, Yogurt, chocolate milk, soft drinks, fruit juice, beer and wine, bakery goods, candies, salad dressing, sauces and jellies. Toothpaste, shampoo, air freshener, lotion and shaving cream. Cough medicine and laxatives. Canned dog food. Paper marbling.

13 i-carrageenan

14 Solution Properties of i-carrageenan Free standing gels by different cation forms of iota-carrageenan. Variation of elastic modulus of iotacarrageenan with cation type. Int. J. Biol. Macromol. 6, , 1984.

15 G'/G" (Pa) Solution Properties of i-carrageenan Na + form 1000 Ca 2+ form Na + form + 50mM NaCl Temperature ( o C)

16 Diffraction Patterns Ca 2+ (II) Na +

17 Molecular Structure

18 Helix-Helix Association Sodium Calcium -20 o c c 13.9 Å 13.6 Å Carbohydr. Res. 335, , 2001; 337, , Å

19 Na + (I) Ca 2+ (II) Ca 2+ (III) Co 2+ Hg 2+ Na + (II) Cu 2+ Na + (III) Cs + Rb + Li + K + Fe 3+

20 Association in Two Polymorphs Ca 2+ Polymorph II Ca 2+ Polymorph III

21 Is Half-Staggered a Molecular Trait? Zn Ni 2+ Ca Ni 2+

22 What is the root cause?

23 What is the root cause? Interactions with two or more guest molecules 2-S Ion W 2-S 4-S W W 4-S 4-S Ion W W W 4-S 2-S W Ion 4-S 4-S Ion W Ion 4-S 2-S W W W 4-S Interactions with two or more guest molecules 2-S Ion W 2-S 4-S W W 4-S 4-S Ion W W W 4-S 2- S W Ion 4-S 4-S Ion W Ion 4-S 2-S W W W 4-S

24 k-carrageenan

25 Solution Properties NaI 0.15% w/w 1.5% w/w G KCl NaI NaCl G Frequency dependence of 1.2% kappa-carrageenan with 0.1 mol/dm 3 salt concentration. Biomacromolecules 2, , Frequency dependence of kappa-carrageenan in 0.2 mol/dm 3 NaI (circles) and 0.2 mol/dm 3 KCl (squares). J. Agric. Food Chem. 49, , 2001.

$Diffraction Patterns$ 1 0 5 3 1 6 4 2 0 Trigonal a =

26 Diffraction Patterns i-carrageenan k-carrageenan Trigonal a = 23.6 and c = 13.2 Å a = 26.7 and c = 25.2 Å

27 Tako s Model --- electrostatic force of attraction ionic bond Bridge : K +, Rb + & Cs + YES Li + & Na + NO

28 Molecular Structure O6H O2 O2H O5 O6 O2

29 Association of i-carrageenan helices

30 k-carrageenan helices Association!?

31 Anti-Parallel Double Helix O6A O6A O2A O2A O2B O2B Non-half staggered Model

32 Packing

33 l-carrageenan

34 Na + -Lambda-Carrageenan + FeCl 3.6H 2 O Na + l-carrageenan Carbohydrate Polymers, In Review

35 Carbohydrate Polymers, In Review l-carrageenan + FeCl 3

36 Domain Model of Carrageenan Gelation J. Mol. Biol. 138, , 1980.

37 Agarose

38 Introduction Agarose is an excellent gel-forming polysaccharide. Extracted from marine red algae. In hot solution the chains exist as disordered configuration, but upon cooling helix formation is evidenced as well as subsequent formation to aggregated thick bundles. The difference between the agarose and carrageenan is in the inversion of the 3,6-anhydrogalactose residue from D to L. Biopolymers 25, , 1986.

39 Agarose Network A schematic representation of the agarose network. In reality the network may contain 10 to 10 4 helices rather than the smaller number shown here!! J. Mol. Biol. 90, , 1974.

40 Solution Properties 0.13% 0.15% 0.10% 0.08% Temperature dependence of elastic moduli of 2% agarose. Biopolymers 59, , Effect of temperature on the elastic modulus of agarose at various concentrations. Carbohydr. Res. 180, , 1988.

41 Three-dimensional Structures No hydrogen bonds between the chains that are stabilized by van der Waals forces!! J. Mol. Biol. 90, , 1974.

42 Three-dimensional Structures Extended single helices!! High temperature dried film Biopolymers 28, , 1989.

Natural Hydrocolloids Physicochemical Properties to Research Initiatives

Natural Hydrocolloids Physicochemical Properties to Research Initiatives Srinivas Janaswamy, PhD Whistler Center for Carbohydrate Research Department of Food Science Purdue University West Lafayette, IN