5 Resistant Starch and Fibre

Food Starches classification

Glycemic

• Degraded to glucose by enzymes in digestive trace

Resistant

• Are not digested in the SI but fermented in LI by bacteria

Glycemic starches categories

Rapidly Digestible Starch (RDS)

• Digest quickly in SI

• Freshly cooked starch foods

  • Ex. Mashed potatoes

• Starch granules have been gelatinized and more accessible to enzymatic digestion

• Converted to glucose within 20 min

Slowly Digestible Starch (SDS)

• Raw starches from a cereal grain

  • Ex. Wheat

• Granule is still intact

• Converted to glucose between 20 - 110 min

Resistant Starches categories

RS1

• Physically enclosed starch

RS2

• Native uncooked starch granules

RS3

• Non granular starch that has been retrograded or crystalline in structure

RS4

• Chemically treated starch that is highly branched and cross-linked

RS5

• Complex molecules which lipid molecules are trapped within helical amylose chains

RS1

Physically enclosed starch

To be digested, seed or outer coating must be broken

• To expose starch granules

Ex. Partially filed grains, seeds, legume

RS2

Native uncooked granules of starch

Less susceptible to digestion until gelatine by cooking

Ex. Bananas and uncooked potatoes

RS3

Non granular starch that has been retrograded or is crystalline in structure

• Amylose and amylopectin chains are no longer in the granule

RS3 starch contains mainly amylose

Ex. Bread, cooked and cooled potatoes

Crystallized Starch vs Broken Granule membrane

Broken granule is easier to digest while crystalline structures are difficult to digest

A commercially developed RS3 is also derived from _______

high amylose cornstarch

RS4

Chemically treated starch that is highly branched and cross-linked

Cross linking limits the ability of digestive enzymes

• Most RS4 starch still undigested in upper GI tract

RS4: Treatment with sodium tripolyphosphate promotes ____ while treatment with sodium trimetaphosphate promotes _____

branching

cross linking

RS5

Lipid molecules tripped within helical amylose chains

Crystalline or amorphous form

Lipids reduces water penetration and swelling capacity during cooking

• Decreases susceptibility to digestive enzymes

What are the potential physiological benefits of resistant starch?

1. Increased throughput of digestive tract

   • Less digestion and more food materials in feces = Greater bulk of faces

2. Increases fecal weight

   • Prevents:

     • Constipation

     • Diverticulosis

     • Hemorrhoids

     • Dilutes carcinogens

3. Produces desirable metabolites

   • SCFA in colon

   • Ex. acetate, propionate, butyrate

4. Butyrate is believed to inhibit growth of cancer cells

Food Applications for Resistant Starch

Moderate and low moisture products

Provides crispiness to crackers, waffles

Can be used as complement to reduced fat and sugar formulations

Can be used to produce high fibre white bread

Resistant starch: Increased Throughput

Less digestion

More food materials in feces

• Greater fecal bulk

Less calories from diet

Benefits from weight loss and blood sugar reduction

Hydrocolloids and Stabilizers: Gums

Wide variety of water soluble thickening and gelling polysaccharides

Hydrocolloids and Stabilizers: Stabilizer

Products that prevent separation of multiple food components during shelf life

Hydrocolloids and Stabilizers: Hydrocolloids

Describes hydrophilic and colloidal characteristics of this class of compounds

Higher viscosity than water

Ability to form a gel

SCFA accumulation

Lowers pH of colon

Inhibits pathogenic MOs

Hydrocolloids and Stabilizers Categories

1. Exudates

2. Extracts

3. Flours or Seed Gums

4. Fermentation Products

5. Chemical Modification

Hydrocolloids and Stabilizers: Exudates

Products from plant sources, usually shrubs or trees

Tapped or sliced to produce a gum like material

Ex. Arabic gum

Hydrocolloids and Stabilizers: Extracts

Isolated or purified functional components derived from seaweed, land plant and animal product raw materials

Ex. Agar, Pectin (from land plants), gelatin (animal origin)

Hydrocolloids and Stabilizers: Flours or Seed Gums

Produced from endosperm of seeds or other ground products

Structural or storage components of plant

Ex. Guar, starches, locust bean gum

Hydrocolloids and Stabilizers: Fermentation products

Industrial femernation allow carbs and other nutrients to be converted to products with gelling properties

Ex. Xanthan Gum

Hydrocolloids and Stabilizers: Chemical Modification

Natural product sources that have been chemically treated to modify their structure and functionality

Functionality

• Emulsification behavior

• Solubility

• Viscosity

• Thermal or acid stability

Ex. Cellulose derivatives, modified starches

What was the original stabilizer for pop drinks?

Arabic gum

The mst important cellulose derivative for food applications is ______

Carboxymethylcelluslose (CMC)

What are the functions f hydrocolloids in foods and nutritional functions?

Functions în foods

• Shape and texture

• Water binding

• Sensory properties

Nutritional functions

• Nutrients

• Dietary fibre

What are the different type of chemical modifications that can be done to hydrocolloids?

1. Cross linking

2. Attaching charged groups

   • Phosphate and succinates

3. Attaching hydrophobic groups

   • Methyl

Beides functioning as texturing agents, hydrocolloids can be used specifically as ______

stabilizers

What are examples of multi component food systems that require stabilization?

Emulsions

Foam

Suspensions

Food Allergy vs Food Intolerance

Allergy

• Proteins acts as antigenic molecules that causes an immune response

  • Through production of immunoglobulin E antibodies

Intolerance

• No immune response

• Adverse reaction to food

• Ex. Lactose Intolerance

________ is the cause of majority of food allergies

Proteins

What are the big 8 foods that account for 90% for all food allergies?

1. Cows Milk

2. Eggs

3. Fish

4. Crustaceans

5. Peanuts

6. Soybeans

7. Tree nuts

8. Wheat (gluten)

Gluten Free Foods: Buckwheat

Not a true cereal

• Not member of grass family

Seeds can be cooked

Buckwheat flour

• Added to cakes, muffins, pancakes to impart a distinctive flavor

Gluten Free Foods: Corn or Maize

Contains 9% protein

Cornmeal is used, not corn starch

• Corn starch used for non-food products

Gluten Free Foods: Millet

Variety of grasses

Protein and iron levels higher than other cereals

Millet flakes

• Can be made into porridge

Millet flour

• Made into pasta

Gluten Free Foods: Quinoa

Not in grass family

Nutritious

• Higher content of protein with good aa composition

• No gluten

  • Cannot be used to make bread

Seeds

• Can be cooked

• Contains high levels of saponins

  • Causes hemolysis of RBC and can be fatal in large quantities

  • Outer coat must be removed for safe consumption

Gluten Free Foods: Rice (Gluten-Free)

Low protein count

Unpolished rice is a good source of B vitamins

Rice flakes

• Puddings or porridge

Rice flour

• cannot be used to make yeasted loaf but can be used for cakes, pancakes

Glycemic index of brown rice vs polished rice

No significant difference

Nutritional value of polished white rice

Fibre and b vitamins removed

Enhanced by parboiling the seed prior to polishing

During parboiling, vitamins and minerals are driven into endosperm

Reduces losses when outer seed coat is removed during posting

What are some reasons for producing polished rice?

1. Aesthetic

   • White color is more attractive to consumers

2. Polished rice cooks faster than brown rice

3. Texture is more softer and more palatable

4. Raw grains have longer shelf life because most of germ and outer seed coat have been removed

   • Outer seed contains polyunsaturated fas

   • Reduces lipid rancidity during storage

What are the major consequences of hemolysis of RBC?

Shortage of oxygen

Oxidation of blood lipids

• Hemolysis causes free iron to enter blood and create toxic free radicals

• Can destroy organs

Soybean allergic proteins

21 identified

Some cause asthma related allergic reactions

Heating enhances allergenicity of proteins in seed hull

Soybean allergic proteins: Major protein fractions

Glycinin

• Generate antibody response

B-conglycinin

• Contains dominant allergen

  • P34

  • Glycoprotein

Epitopes

Linear sequences of aas to which antibody binds to cause an immune reaction

Must remain intact to bind and cause immune reaction

P34 contains 12 different epitopes

Heat treatment

• Does not reduce allergenicity

• Does not destroy epitopes

If an epitope is destroyed ______

there can be no immune reaction

Why does heating enhance allergenicity of proteins in soybeans?

Heating causes proteins to unfold and allergic sequences become more exposed

Epitope and P34 destruction

Fermentation

• May reduce P34

• Fermentation produces enzymes that hydrolyze P34 and destroy epitopes

Enzymatic hydrolysis

• Proteases can reduce P34 allergenicity because epitopes are digested

Protein extrusion (High heat and pressure)

• Destroys P34 allergenicity

• Physical fragmentation of epitopes

Hypoallergenic foods definition

Foods that have been shown to cause reaction in 90% of patients who are known to be allergic to the parent food

Hypoallergenic foods: Influence of molecular size

Proteins smaller than 10000 daltons are weak due to few epitopes

Peptides less than 2500 are not immunogenicity without modification b/c absence of epitopes

Strong immunogenicity have multiple antigenic binding sites

Weak immunogens have at least 2 epitopes

Higher number of epitopes on a protein, _____

The stronger the immune reaction

Characteristics of food allergens

1. Must be stable in food processing conditions so epitopes remain intact

2. Must resistant digestion by acid and digestive enzymes to preserve epitopes

   • Stomach and intestinal tract

3. Must be able to cross-link leg antibodies through epitopes

   • Hydrolysis of epitopes eliminates allergenicity

AAs vs Peptides (Protein hydrolysates) as hypoallergenic agents

Peptides

• Less hypertonic

  • Improve absorption efficiency and reduces osmotic problems

• Less susceptible to interference from carbs

• Better taste

_______ have been found to behave like fibres by lowering blood cholesterol

Some indigestible proteins from soybean and buckwheat

What is the most abundant insoluble dietary fibre and carb in nature?

Cellulose

Powered cellulose at 99% total dietary fibre (TDF) is available from several sources, because ____

it is almost pure TDF, and considered non-caloric

Powered Cellulose

Raw materials treated to remove lignin and other impurities, and milled

90% b 1,4 glucan and 10% hemicelluloses

____ can be processed into food-grade cellulose

other sources besides foods

Fibre derived from oat hulls is produced is predominantly composed of __

cellulose

Oat fibre can be used at up to 4 to 5% in formulated foods, higher levels might result in ____

Unacceptable textures scubas bad mouthfeel and dryness

Protein allergenicity is directly proportional to _____

the number of epitopes on the protein

Cottonseed fibre

Another form of cellulose

Used in formulations for baked goods

• Enhances fibre content and reduces fat and calorie content

Composition the same as wood-derived cellulosic fibre

• Same functions and applications

Fibre length and cellulosic fibre

Water holding depends on fibre length

• Longer holds more water

Longer fibre increases the viscosity of for system

Water uptake is proportional to the length of the capillary in the fibre

Soluble dietary fibre

Food gums

Able to interact with water better than insoluble fibres

What is the most widely available soluble fibres?

Pectins

Soluble Fibres: Pectins

Galacturonic backbone with possible side chains of monos

Wide range of functions as a water binder

Pecitns: High methoxy (HM) vs Low methoxy (LM)

HM

• Used in fast setting firm gels

• Negative charges are neutralized

LM

• Used in slower setting softer gels

• Some negative charges are still present

  • Some repulsion

Soluble Fibres: Konjac

High molecular weight polysaccharide made of glucose and mannose sugars

Konjac flours produces viscosities higher than guar gum or pectin

• Useful texturing properties at low concentrations

Soluble fibres: Benefibre

Hydrolyzed guar gum

80% minimum soluble dietary fibre

Very low viscosity

Soluble in cold water

No color or off flavor at 5% solids

There is evidence that partially hydrolyzed guar gum _____

favours the growth of bifidobacteria in the intestines

Soluble Fibres: Fibregum

Physically processing gum acacia results in 85% soluble fibre

Can be used at high levels of solution with minimal effect on viscosity

Soluble Fibres: B-glucans

Glucose polymers with b 1-4 and 1-6 linkages

Largest quantities in barley, oats and rye

Oatrim

• Hydrolyzed oat flour that contains 5% b-glucan

Wood Pulp

Waste product of lumber industry

Contains high levels of cellulose

Main components of hydrocolloids

1. Hexoses

   • Glucose, galactose, mannose

2. Sugar acids

   • hexuronic, glucuronic, galaturonic acids

3. Pentoses

   • Arabinose, rhamnose, xylose

Sugar acids

Made through oxidation of sugars

Nomenclature

• Replace “ose” in sugar with “uronic”

Choice of food hydrocolloid is based on:

1. Functional properties being sought

   • Textures or stabilizations

2. Rheological characteristics

   • Ex. elasticity

3. System components that interact with hydrocolloid

   • Acids, salts, proteins, fats

4. Different processing techniques

   • Time, temp, shear

5. Others

   • Shelf life

   • Cost and availability

   • Nutrition

   • Religion

Cellulose and Other cell wall components

1. Hemicelluloses

2. Lignin

3. Pentosans

CELLULOSE AND OTHER CELL WALL COMPONENTS: Hemicelluloses

Mixture of alkali soluble polysaccharides

• Composition varies with extraction procedures

Main cell wall component of fruits, veggies and cereals

Content increases with maturity

• Highly concentrated in pericarp tissues of cereals

• Low concentration in endosperm of starches

Ex. Polymers of mannose, galactose, xylose

Lignin: Trace amounts and Large amounts

Found in trace amounts of high quality fruits and veggies

Found in large amounts in bran of cereal grains and in some spices

CELLULOSE AND OTHER CELL WALL COMPONENTS: Pentosans

Polymers of pentoses and methyl pentoses

Wheat endosperm belong to arabinoxylan series of polysaccharides

Wheat flour contains about 3% total pentosans, of which about 1/3 is _____

water soluble and contributes to baking quality

Carrageenans

Seaweed extract

Most important red seaweed polysaccharides used by food industry

Contains three fractions

1. Lambda

2. Iota

3. Kappa

Normal Pectin

Highly negative charged

• Hard to form a gel due to repulsions

Carrageenans: Lamda

No gel formation

Forms high viscosity liquids

• Excessive repulsions between negatively charged sulphate groups

• Prevents molecules from being able to crosslink to form gels

Carrageenans: Iota

Forms elastic gels

Lower number of sulphate groups

• Reduced repulsions

  • Weak interactions to form soft and elastic gels

Carrageenans: Kappa

Forms rigid gels

Interact with K+ and Ca2+ to form elastic gels

• Introduces more repulsion

• Interactions become weaker and form elastic gels

Least number of sulfate groups

• Minimal repulsions

• Strong molecular interaction to form rigid gels

_______ determines functionality of carrageenans

Number of sulfate groups

Carrageenanans interacts with starch to ___

increase resistance of starch to shear induced degradation

Fragmented vs Whole Carrageenan

Fragmented may cause cancer

Only whole carrageenan is permitted in foods

Alginates

Linear copolymers of mannuronic acids (M blocks) and glucuronic acids (G blocks)

Contains regions composed entirely of one of the acids

• Ex. MMMMMMMMGGGGGG

Used in production of difficult to manufacture foods

Heat stable

• Used in preference to other thermoreversible gelling systems

Gelling agents in ice cream or stabilizers in combination with phosphates

• Sequesters Ca in milk which allows alginate to dissolve

Good thickener

Alginates gels rich in glucuronic acid vs aliginates rich in mannuronic acid

Alginates rich in glucuronic acids are:

• Stronger

• More brittle

• Less elastic

Alginate gels are formed under cold conditions by ___

Ca-induced intermoelcular associations involving G block region, which have a geometry suited to the cooperative binding of calcium ions

At low pHs, alginates will _____

gel and cannot be added as stabilizers to products such as fruit juices, salad dressing etc

G-Block

Interacts w/ Ca+ to form gels

• Ca neutralizes negative charges on the G-block to promote gel formation

Called cold gelation

• saves on heating costs

Alginate gels vs Other gels vs Most gels

Alginate

• Thermal Resistant

• Heating gel does not change form

Other

• Thermoreversible

• Heating gel turns it into viscous solution

Most

• Heat and cooled

• Heat induced gels

What does the physical process do in fibre gum?

Grinding to produce small particle sizes

Small particles have large surface area to bind water

Alpha vs Beta glycosidic bond digestion

We cannot digest beta glycosidic bonds

• Only alpha

Oatrim flour use

Used primarily in baked goods