AMITY INSTITUTE OF FOOD TECHNOLOGY CREDIT SEMINAR TOPIC- Food Hydrocolloid PRESENTED BY- Sujata Mishra E.NO. - A4312608018 BATCH- 2008-12 ABSTRACT A hydrocolloid is defined as a colloid system wherein the colloid particles are dispersed in water . A hydrocolloid has colloid particles spread throughout water, and depending on the quantity of water available that can take place in different states, e.g., gel or sol (liquid). Hydrocolloids can be either irreversible (single-state) or reversible . For example, agar , a reversible hydrocolloid of seaweed extract, can exist in a gel and sol state, and alternate between states with the addition or elimination of heat. Many hydrocolloids are derived from natural sources. For example, agar-agar and carrageenan are extracted from seaweed, gelatin is produced by hydrolysis of proteins of bovine and fish origins, and pectin is extracted from citrus peel and apple pomace ). Other main hydrocolloids are xanthan gum , gum arabic , guar gum , locust bean gum , cellulose derivatives as carboxymethyl cellulose , alginate and starch. Hydrocolloids are among the most widely used ingredients in the food industry. They added to control the functional properties of aqueous foodstuffs. Most important amongst these properties 1
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AMITY INSTITUTE OF FOOD TECHNOLOGY
CREDIT SEMINAR
TOPIC- Food Hydrocolloid
PRESENTED BY- Sujata Mishra
E.NO. - A4312608018
BATCH- 2008-12
ABSTRACT
A hydrocolloid is defined as a colloid system wherein the colloid particles are dispersed in water. A
hydrocolloid has colloid particles spread throughout water, and depending on the quantity of water available
that can take place in different states, e.g., gel or sol (liquid). Hydrocolloids can be either irreversible (single-
state) or reversible. For example, agar, a reversible hydrocolloid of seaweed extract, can exist in a gel and sol
state, and alternate between states with the addition or elimination of heat.
Many hydrocolloids are derived from natural sources. For example, agar-agar and carrageenan are
extracted from seaweed, gelatin is produced by hydrolysis of proteins of bovine and fish origins, and pectin is
extracted from citrus peel and apple pomace). Other main hydrocolloids are xanthan gum, gum arabic, guar
gum, locust bean gum, cellulose derivatives as carboxymethyl cellulose, alginate and starch.
Hydrocolloids are among the most widely used ingredients in the food industry. They added to control
the functional properties of aqueous foodstuffs. Most important amongst these properties
are viscosity (including thickening and gelling) and water binding but also significant are many others
including emulsion stabilization, prevention of ice recrystallization and organoleptic properties. The degree
with which the hydrocolloid solutions mix with saliva, determined by their degree of chain entanglement,
determines flavor perception. Products reformulated for fat reduction are particularly dependent on
hydrocolloids for satisfactory sensory quality. They now also find increasing applications in the health area as
dietary fibre of low calorific value. Other more specialist applications include adhesion, suspension,
flocculation, foam stabilization and film formation.
My objectives of studying Food Hydrocolloids are:-
(1) To study function of food hydrocolloids in food processing.(2) To study the application of food hydrocolloid in food industry.(3) To study the origin of hydrocolloids.(4) To study the properties of food hydrocolloids.
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REVIEW OF LITERATURE
General properties of hydrocolloids
Hydrocolloids are used either alone or in combination to achieve specific synergies between their
respective functional properties. While stabilising, emulsifying, thickening and/or jellifying the solid or liquid
products, they also enhance the whole food’s structure and improve the mouthfeel. Depending on the nature of
the food products, hydrocolloids provide either firmness or softness; in any case a stable consistency to the
finished products.
In bakery products they bind the dough moisture and improve its retention, which in turn keeps the
dough fresh during its shelf life. They inhibit possible syneresis in yoghurts, impede flocculation (e.g. in milk
beverages) during shelf storage and stabilise food and beverage emulsions in general.
They strengthen the heat stability of dairy products and control melting processes items like ice creams and
frozen desserts.
Hydrocolloids have a neutral taste and aroma which permits a free flavour release of all recipe
components. They provide an unctuous body to fat-reduced products, in which they compensate for the low
fat content with their water-binding ability and texturising properties.
They also help create a fat-like jellified structure that remains stable throughout the product’s shelf
life and pleasantly melts in the mouth to yield a full flavour release during consumption. This property is
widely used in the production of fat-reduced dairy and meat products. Hydrocolloids perform a true
bodybuilding function in foodstuffs and act as a warrant for shape stability, perfect consistency, freshness and
harmonised texture.
R.No.- 1,2(a),(b)
Characteristics of Hydrocolloids
The unique and unifying characteristic of hydrocolloids is their ability to interact with water and form
gels at very low concentrations. Gels are essentially three-dimensional interconnected molecular
networks that exhibit varying degrees of strength, stability and ability to entrap water and manage its
migration.
Another common characteristic of hydrocolloids is their tendency to form colloidal solutions.
Distinctly different, colloidal solutions are relatively stable and generally viscous. In colloidal
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solutions the hydrocolloid particles retain a measurable size and may be separated from their
dispersing solution by passing through a semi-permeable membrane.
R.No.- 1,2(b)
Classification of Hydrocolloid
Hydrocolloids are classified as either thickening or gelling agents.
(1) On the basis of gelling property:-
Hard/Soft: How much force does it take to rupture the gel?
Brittle/Elastic or Springy: Does the gel break suddenly or deform? After the first bite, does the gel
return to its original height?
Cohesive: Is the gel difficult to break up in the mouth? Does it stay together?
Gummy: Is the gel hard and cohesive?
Chewy: Is the gel both gummy and springy?
Adhesive: Does the gel adhere to the teeth or palate?
Characteristics of Gels
Important characteristics of gels are:
Thermo-reversible/Irreversible: Thermo-reversible gels melt when heated to a high enough
temperature (with the exception of methylcellulose, which forms thermo-reversible gels that set when
heated and melt when cooled). Thermo-irreversible gels will not melt when heated. Some gels are
thermally reversible, but the melting temperature is so high that they don’t melt in practice (high-acyl
gellan).
Tendency for Syneresis: Syneresis occurs when liquid weeps out of a gel over time, as happens in
custards. Agar is prone to syneresis; water can be expelled merely by pressing on it. Some gels only
experience syneresis after long periods of time. Many gels that are ruined by freezing (see freeze-thaw
stability, below) tend to weep when thawed. Within a given hydrocolloid system, harder gels tend to
weep more than softer ones.
Freeze-thaw stability: Gels that may be frozen and thawed repeatedly are called freeze-thaw stable.
Many gels begin to degrade after freezing; only one freeze-thaw cycle is advised. When an unstable
gel is frozen and later thawed, its texture and structural may be compromised by the physical changes.
To offset this effect and promote freeze-thaw stability, a second thickening hydrocolloid may be added
to the gel system.
Clarity: The addition of some hydrocolloids yield gels that are more transparent than others.
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Flavor release: Flavor release describes how well a gel expresses the flavorings with which it has
been made. Flavor release is determined by many gel texture properties. Gelatin, for example, is
considered to have excellent flavor release mainly because it melts in the mouth, whereas alginate is
said to have poor flavor release because it tends to lock up flavors.
Shear reversibility: Shear is a force in which parallel objects move in opposite directions in a
“sliding” motion, such as in the action of scissors cutting or a razor shaving. Stirring produces a shear,
as does blending. Very fast blenders are called high-shear blenders. A shear-reversible gel will reform
after it has been broken by a shear force. Most gels are not shear reversible.
(2) On the basis of thickening property:-
Gel Flow Properties
Hydrocolloids that thicken are judged by the flow properties they produce:
Shear thinning: Water has the same viscosity no matter how fast or how hard it is stirred. Liquids that
display this characteristic are called Newtonian fluids. Most hydrocolloids, however, display non-
Newtonian behavior tend to get thinner as they are sheared (known as pseudo-plastic behavior). Large
tangled hydrocolloid molecules that are aligned randomly in solution tend to be thick. As shear is
applied to the solution and the molecules start to move, they tend to align themselves in planes,
causing them to grow thinner the more vigorously they are stirred.
Yield point: Some hydrocolloids act like a gel when standing still and liquify instantly under shear.
Hydrocolloids with yield points, such as xanthan gum, are useful as stabilizers in foods like salad
dressing. The dressing acts like a gel when it’s sitting on the table: the oil droplets stay dispersed in the
bottle. But when the dressing is poured, it flows like a liquid. A related term sometimes used
synonymously with yield point is thixotropic. Thixotropic fluids, such as ketchup, act as a solid until
they are sheared with sufficient force for sufficient time.
Fluid gels: Hydrocolloids can also form fluid gels. Fluid gels have the properties of both a fluid and a
gel. Agar fluid gels can look like hair gel on the plate but feel like a smooth, creamy sauce in the
mouth. Gellan can make a fluid gel that diners will experience like a soup but that will suspend large
particles as if it were solid.
CONSIDERATIONS WHEN USING HYDROCOLLOIDS
Forming Gels: -It is extremely important to understand when and why a hydrocolloid gels since this
behavior typically determine which hydrocolloid is appropriate to use.
Heating and Cooling: - Many hydrocolloids gel when cooled. Sometimes these gels can be melted
again, such as gelatin, and sometimes they cannot, such as the pectin in a jam. Methylcellulose forms a
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gel when heated that melts on cooling. Some thermally reversible gels show temperature hysteresis,
that is, the setting temperature of the gel is lower than the temperature needed to melt the gel. This
property can be very important to a chef. For example, agar sets around 35°C but melts at around
90°C. The low set temperature makes agar easy to work with, and the high melt temperature allows
agar preparations to be served hot. Thermally formed gels can also be slow set or snap set. Snap
setting hydrocolloids, like gellan, gel instantly below their gelation temperature.
Calcium and Potassium: - Some hydrocolloids form gels in the presence of positively charged ions,
mainly calcium and potassium. In these instances, the positive ion fits into negatively charged areas in
the hydrocolloid, allowing two hydrocolloid molecules to stick together in a structure similar to an
egg-crate. In some cases, like alginates, these gels are not reversible; in others, like kappa carrageenan,
thermo-reversible gels are formed. It is extremely important to control the amount of calcium in
solution when dealing with calcium-dependent hydrocolloids. If too much calcium is present, the
hydrocolloid will gel immediately, a process that is called pre-gelation.
Sometimes, the hydrocolloid simply will not hydrate in a recipe. In these cases, chemicals called
sequestrants are added to these solutions to prevent pre-gelation and allow proper hydration.
Sequestrants have the ability to bind with ions like calcium more effectively than hydrocolloids can. In
many cases, the amount of calcium in tap water alone can cause pre-gelation of a hydrocolloid if not
treated with sequestrants. Acidic solutions (low pH) also need more sequestrants than neutral solutions
because many calcium impurities are more soluble and affect hydrocolloids more at low pH (see
section on calcium salts and sequestrants).
Synergy, 1+1=3:- Hydrocolloids do not act like most ingredients. In general, do not expect to be able
to mix two hydrocolloids without changing their properties. When two liquids of the same viscosity
made with different hydrocolloids are mixed, the viscosity often does not stay the same, but increases.
The hydrocolloids have a synergistic increase in viscosity. This effect is used by manufacturers to save
money, because they can use a smaller quantity of hydrocolloid in a synergistic system. Another
example of synergy is when xanthan gum and locust bean gum, normally non-gelling thickeners, are
mixed. Surprisingly, they form a gel. This is called synergistic gelation. Sometimes, hydrocolloids will
show synergism with a particular non-hydrocolloid ingredient. For instance, carrageenan plus milk
gels at half the concentration of carrageenan plus water.
As a rule of thumb, gelling hydrocolloids and thickening hydrocolloids can often be mixed to get the
benefits of both (locust bean gum can be added to kappa carrageenan to give it a better texture, for
example) without synergistic effects that will damage a recipe. Charged and uncharged hydrocolloids
can also often be mixed without incident, like methylcellulose and alginate.
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Hydration: - For a hydrocolloid to work properly, it must be hydrated and dissolved in solution. When
a recipe fails, the problem is frequently improper hydration. Hydration procedures vary from
hydrocolloid to hydrocolloid, but there are some important general rules. Hydrocolloids added to water
tend to swell as they unfold into solution. The swelling causes particles to clump together forming
lumps that are very difficult to dissolve. Many hydrocolloids are even more lump-forming than starch.
The trick to hydrating hydrocolloids is to get good dispersion –keep the hydrocolloid particles
separated before they start to swell, hydrate, and cause lumps. Industrially, hydrocolloids are often
mixed with a non-solvent, like alcohol or corn syrup, or an easily dissolved powder like sugar. This
pre-mix helps the hydrocolloid particles get away from each other while they hydrate.
In general, hydrocolloids like to be hydrated in pure water. Large concentrations of sugar, salt, starch,
alcohol, or anything that competes with the hydrocolloid for water can hinder hydration. Sometimes a
hydrocolloid will not hydrate in a recipe. Alginates, for instance, will not hydrate in acidic liquids. In
these cases, the hydrocolloid can be pre-hydrated in pure water, and the resulting solution can usually
be added to the recipe without a problem. It is a good practice to add hydrocolloid as early in a recipe
as possible.
Recipe Formulations and Measuring: - Hydrocolloids are usually specified in percent by weight.
One kilogram of 2% alginate solution contains 980 g of water and 20 g of alginate.
Calcium Salts and Sequestrants: - Calcium sequestrants (chemicals that bind calcium ions) are
difficult to understand. The two sequestrants most used by chefs are sodium citrate and sodium
hexametaphosphate (SHMP). Sodium citrate only works in systems above a pH of 4, while SHMP
works in all the pH ranges a chef will ever use. For most applications, SHMP at 0.1% will provide
good sequestering ability.
Different recipes specify the use of different calcium salts. The three most common are calcium
chloride, calcium lactate, and calcium lactate gluconate. Calcium chloride is 36% calcium, is
inexpensive, and is very soluble in water, but has a terrible taste. Calcium lactate is 13% calcium, is
more expensive, and is not nearly as soluble as calcium chloride, but it tastes much better. Calcium
lactate gluconate, or calcium gluconate, is only 9% calcium, is much more expensive than the others,
and is not very soluble—it needs to be dissolved in hot water, but is flavorless.
Dispersion & Dissolution: - Hydrocolloids that form gels are easily dispersed when conditions are
favorable for gelling. Dispersion (getting hydrocolloid particles as far away from each other as
possible before they start to absorb water and swell) is simple to do when a hydrocolloid is added to
water in a state favoring gelling because they are not soluble in that state.
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Dissolution cannot happen when conditions are favorable for gelling. Gelatin cannot be dissolved in
cold water. Kappa carrageenan cannot be dissolved in potassium-filled cold water. Hydrocolloid
recipes often call for the addition of a hydrocolloid in conditions that favor gelling, to allow
dispersion, and then specify putting the hydrocolloid in a condition that doesn’t favor gelling, to allow
dissolution and hydration.
Hydration tip: - Blenders use high shear to beat particles away form each other and achieve good
dispersion throughout a mixture.
Function and features of hydrocolloids in food processing
Application Necessary functionality and features needed for best performance
Emulsification in beverages Coating of an oil droplet by the high molecular weight fraction rich in protein (AGP). Direct correlation between the proportion and molecular weight of the AGP and the emulsification performance and stability due the elasticity of film formed at the interface. Heat induced hydrophobic associations in the solid state result in the highest performance due to increasing the proportion of the AGP. This is the basis of enhanced gums commercially available under the trade name Supergum™.
Confectionary Preventing sugar crystallisation and emulsifying fat to ensure even distribution throughout the product. Long- term emulsion stability is notrequired particularly for products with high sugar and low moisture contents such as jujubes, pastilles, caramel and toffees. Thickening properties (viscosity) and film forming are required as a glaze in candy products. Binding agent for the paste base.
Encapsulation of essential oils; aromatic compositions, plant essences. Oleoresin spices, fruit juices, vitamins, polyunsaturated fatty acids, enzymes, acids, traceelements, mineral oils, pesticides
Forming a protective film to avoid penetration of oxidising agents, and allowing controlled release. Need for increased wetability and good viscosity control. Typically, A. seyal is used since it has lower viscosity and can sufficiently provide shortterm emulsion stability prior to spray drying. Higher concentration of gum can also be used to provide a matrix as well as encapsulation.
Bakery for toppings and glazes Free flowing, adhesion properties, control the water absorption and to impart smoothness.
Texture and flavour modification in confectionery
Interact and bind water, to thicken as a gel. Gel formation with enhanced water absorption. High proportion of AGP.
Foam stabilization- structure forming
“Lace curtain” effect on beer. Maximise content of high molecular weight component rich in protein which responsible for producing thefoams. Other products include marsh mallows and whipping creams.
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Wine Emulsifier and stabiliser for colour particularly in red wine by forming a protective film layer to prevent precipitation; reduce perception ofacidity and tannin harshness; provide sensory impacts that include nose, palate and mouth feel modifications. Best performance achievedwith high proportion of AGP to give long-term emulsion stability.
Dietary fibre Dairy products, processed fruits, bakery items, frozen desserts, meat products and food for diabetics. Need ability to fermentation in colon togive short-chain fatty acids, with bulking ability. A. seyal is typically used due to its low viscosity compared to A. senegal.
R.No.- 2(a),(h),(f)
Natural hydrocolloids
Though alike in many ways, hydrocolloids also have many differences with respect to their property and
compatibility. The choices require consideration of the entire product spectrum from mixing and processing,
through finished product attributes, storage and end use.
Carrageenans [E-407]
It is an anionic polysaccharide, extracted
principally from the red seaweed Chondrus crispus. It is
approved for GRAS food substance under section 172.620
in Title 21 set by the U.S. Code of Federal Regulations (21
CFR 172.620). They form a special subcategory among the