FOOD CHEMISTRY BY DR BOOMINATHAN Ph.D. M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGSWI, Israel), Ph.D (NUS, SINGAPORE) PONDICHERRY UNIVERSITY Fifth lecture 13/August/2012

Goals Structural arrangements of different Gums: Carrageenans, Guar gum, Carbogum, Xanthan, and Gum arabic Composition Physico-chemical properties of Gums Applications of Gums in food industry

March 5, Southern Bio-products Conference Polysaccharides Carrageenans Ionic Gums

Carrageenan – obtained by extraction with water or alkaline water of certain Rhodo phyceae (red seaweed). It is a hydrocolloid – consisting mainly of the potassium, sodium, magnesium, and calcium sulfate esters of galactose and 3.6-anhydro- galactose copolymers. – nonhomogeneous polysaccharides 3 types: Kappa, lambda, iota

Three types of Carrageenans

Carrageenans Kappa Lambda

Structural changes of Carrageenans at different temperatures Hot In a hot solution, the polymer molecules are in a coiled state. As the solution is cooled, they intertwine in double-helical structures. As the solution is cooled further, the double helices are believed to nest together with the aid of potassium or calcium ions. Cold coiled state double-helical structures Ca 2+ double helices are believed to nest Cold Gelation

Comparisons of different Carrageenans Characteristics KappaIotaLambda Solubility 20° C waternonoyes 80° C milkyesyesyes 20° C milknonothickens Gelation With addition of:K +Ca++None Stability Freeze – thawnoyesyes pH > 5stablestablestable Syneresisyesnono Salt tolerancepoorgoodgood

Protein - Carrageenan Interactions Protein (milk) with a negative charge Protein (milk) with a positive charge Reacts with casein milk protein The thickening effect of kappa-carrageenans in milk is 5–10 times greater than it is in water. Useful in the preparation of chocolate milk, icecream, evoporated milk etc.

Carrageenan: Application of carrageenan in meat protection 3 categories of meat: 1. pale, soft, and exudative (PSE) Due to postmortem generation of lactic acid 2. dark, firm, and dry or non-exudative (DFD) 3. "normal" meat acceptable subjectively between PSE meat and DFD meat Function: Carrageenan + soy protein: – Prevents occurrence of PSE meat Concept: Use of carrageenan is to hold water and maintain water content, and therefore softness of meat products, such as sausages, during the cooking.

Carrageenan softens meats Carrageenan is a water-soluble polymer, also known as a gum, that is used as a fat substitute in processed meats and can be found in condensed milk and some soy milk products. Normally, fat serves the purpose of maintaining softness, but because of the binding power of carrageenan for protein and its high affinity for water, Carrageenans can be used to replace in part this function of natural animal fat in lean products.

March 5, … However Carrageenan may cause stomach lesions, cancer Strawberry cheesecake like this may be stabilized and thickened with carrageenan. Containers of pudding, ice cream, yogurt, or cottage cheese may include the ingredient carrageenan, a thickener derived from red seaweed. For decades, it has been presumed to be safe to eat, but new research from a medical doctor on the faculty of the University of Iowa shows that presumption may be wrong.

Typical Dairy Applications of Carrageenan Milk Gels Cooked flans (open pastry filled with fruit or custard) or custards (Sweetened mixture of milk and eggs baked, boiled or frozen) – GelationK, K + I Cooked prepared custards – Thickening – GelationK, I, L Pudding & Pie Fillings Dry mix cooked with milk – Level starch gelatinization Ready-to-eat – Syneresis control, bodying

Typical Dairy Applications of Carrageenan Whipped products – Whipped cream Stabilize overrun – Aerosol whipped cream Stabilize overrun & emulsion Cold prepared Milks – Instant Breakfast Suspension, bodying agent – Shakes Suspension, bodying

CarrageenanCarrageenan: Summary Structure: Galactose backbone Ester sulfate gives negative charge Properties: Gels with potassium (Kappa) Gels with calcium (Iota) Non-gelling (Lambda) Applications: Good stabilizer for milk proteins Suspender for chocolate in milk Part of ice cream stabilizer mix Water gels

Questions Commercial carragennan contains: 1. Kappa 2. Iota 3. Lamda 4. a mixture of above The viscosity of carrageen is quite stable over a wide range of pH values because 1. sulfate half-ester groups are always ionized 2. Phosphate groups are never ionized 3. Phosphate groups are always ionized 4. Nitro groups are always ionized

Questions Lambda carragennan contains: 1. the maximum no. of sulfates 2. the lowest no. of sulfates 3. only one sulfate 4. none Carrageen softens meat due to its 1. binding power for protein 2. high affinity for water 3. both

Non-ionic Gums Guar gum & Carobgum

Guar gum

Guar Gum Guar gum is the ground endosperm of seeds Guar gum Monomer: galactose, mannose (galactomannan) Bonding:  -1,6/  -1,4

MannoseGalactose Glucose

Guar gum Monomer: galactose, mannose (galactomannan) Bonding:  -1,6/  -1,4 a main chain of b-D-mannopyranosyl units joined by (1-- 4) bonds with single-unit a-D- galactopyranosyl branches attached at O-6 Mannose Galactose

Guar Gum It produces the highest viscosity of any natural, commercial gum Galactomannan (Mannose (1-4) + Galactose (1-6) every other Mannose Galactomannans consist of MW 220,000 ± 20,000 Particle size affects viscosity and hydration Cold water swelling - Turbid solutions

Guar Gum Hydration increased by heating High water binding High viscosity form - up to 100,000 CP Low viscosity from - up to 10,000 CP Modifies properties when used with: –Carrageenan –Xanthan

Guar Gum Characteristic of different grades of Guar Gum GradeCold Viscosity.Hydration RateDispersability Coarse2,700SlowExcellent Medium3,800ModerateExcellent Fine4,000FastFair Powder4,300V. FastPoor

Food Uses Ice cream prevents ice crystal formation, slows meltdown, improves heat shock resistance Salad dressing viscosity Cheese improves spreading

Guar gum uses in food industry Ice creams: Smooth creamy texture Bakery products: Texture, moisture retention Noodles: Moisture retention, machine runnability Beverages: mouth feel Meat: Binder, absorb water Dressings: Thickener, emulsion stabilizer

Carobgum

30 Carobgum is the ground endosperm of seeds Carobgum

March 5, Southern Bio-products Conference Carobgum –obtained from the endosperm of the Carob or locust seed (Ceratonia siliqua).

Monomer: galactose, mannose (galactomannan) Bonding:  -1,4/  -1,6 (branch) Seed Gum Carobgum

Carob Gum Galactomannan (D-Mannose (1-4) with Galactose (1-6) every 4th mannose Mannose Galactose

Carobgum Galactomannan (D-Mannose (1-4) with Galactose (1-6) every 4th mannose Molecular weight 330,000 ±30,000 Neutral - relatively unaffected by ions, pH. Not soluble in cold water Fully hydrated if heated 10 minutes at 80° C Solutions are turbid, off-white Modify properties of –Carrageenan –Xanthan Gum

March 5, Southern Bio-products Conference Carobgum retards ice crystal growth shows viscosity synergy with xanthan.

Guar gum and Carobgum

Gums-Guar gum and Carobgum 37 B) Non-ionic gums Guar gum and Carobgum – No effect of pH and ions (salts) since they are uncharged – Guar gum has galactose side- groups on every other mannose unit (2 monnose:1 galactose) while carobgum does not have uniform distribution (4 mannose:1galactose) or irregular

Carbogum Gums-Guar gum and Carobgum

39 B) Non-ionic gums Guar gum and Carobgum: – Guar gum : soluble in hot/cold water; very viscous solutions at 1% ; and it forms gels and films at 2-3% Guar gum produces the highest viscosity of any natural, commercial gum Used in Ground meats, salad dressings and sauces…… – Carobgum: Soluble at 80/90 o C; very viscous solutions; Synergises with xanthan gum or carrageenan Used as a Binder in meat products and in frozen desserts Gums-Guar gum and Carobgum

Questions Guar gum and carbogum are examples for: 1. Ionic gums 2. Non-ionic gums 3. Both 4. None pH and ions can change the property of Guar gum and carbogum 1.True 2.False 3.Only pH 4.Only ions