The use of carrageenan in food

Abstract

Carrageenan is the leading seaweed derived food hydrocolloid and is used widely for its textural functionality, particularly in dairy products, jellies and confectionery and in cooked processed meat products. Current market data from the hydrocolloids sector shows carrageenan to have the fourth largest share of the global food texture market (in terms of value), behind starches, gelatine and pectin. Estimates of global carrageenan production for 2015 (provided elsewhere in this book) are in the region of 68,000 tonnes (dry weight). With the growing demand for processed food, especially in developing economies around the world where significant new market opportunities are opening up, the global food texture market is expected to keep growing at a significant rate and thus continued demand for carrageenan seems assured. Hydrocolloids are typically used in food products to improve appearance (e.g., creaminess, homogeneity) and organoleptic qualities (e.g., mouthfeel, juiciness); to promote easy-use application (e.g., pourabilty, spreadability); to impart processing benefits such as freeze-thaw stability, sliceability, retain freshness and increase shelf life and also to improve yields. Thus offering a range of technical and cost benefits to producers. Hydrocolloids are also finding increased application in the formulation of healthier foods as the food industry rises to the challenge of meeting global targets for the reduction of “unhealthy” ingredients such as salt (sodium), sugar and fat. Detail on the sources, production and specific chemistry of commercially available carrageenan is given elsewhere in this book. This chapter will therefore specifically focus on the properties of different types of carrageenan and illustrate how they are utilised in a range of food applications.

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In: Carrageenans ISBN: 978-1-63485-503-7
Editor: Leonel Pereira © 2016 Nova Science Publishers, Inc.
Chapter 10
THE USE OF CARRAGEENAN IN FOOD
Sarah Hotchkiss*, Mariel Brooks, Ross Campbell,
Kevin Philp and Angie Trius
CyberColloids Ltd, Unit 4A, Site 13, Carrigaline Industrial Estate,
Carrigaline, Co. Cork, Ireland
ABSTRACT
Carrageenan is the leading seaweed derived food hydrocolloid and is used widely for
its textural functionality, particularly in dairy products, jellies and confectionery and in
cooked processed meat products. Current market data from the hydrocolloids sector
shows carrageenan to have the fourth largest share of the global food texture market (in
terms of value), behind starches, gelatine and pectin. Estimates of global carrageenan
production for 2015 (provided elsewhere in this book) are in the region of 68,000 tonnes
(dry weight). With the growing demand for processed food, especially in developing
economies around the world where significant new market opportunities are opening up,
the global food texture market is expected to keep growing at a significant rate and thus
continued demand for carrageenan seems assured.
Hydrocolloids are typically used in food products to improve appearance (e.g.,
creaminess, homogeneity) and organoleptic qualities (e.g., mouthfeel, juiciness); to
promote easy-use application (e.g., pourabilty, spreadability); to impart processing
benefits such as freeze-thaw stability, sliceability, retain freshness and increase shelf life
and also to improve yields. Thus offering a range of technical and cost benefits to
producers. Hydrocolloids are also finding increased application in the formulation of
healthier foods as the food industry rises to the challenge of meeting global targets for the
reduction of “unhealthy” ingredients such as salt (sodium), sugar and fat.
Detail on the sources, production and specific chemistry of commercially available
carrageenan is given elsewhere in this book. This chapter will therefore specifically focus
on the properties of different types of carrageenan and illustrate how they are utilised in a
range of food applications.
Keywords: carrageenan, refined, semi-refined, hydrocolloid, gelling, texture
* Corresponding author: email: sarah@cybercolloids.net.
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1. INTRODUCTION
The historical use of carrageenan in Asia and Europe is well documented [1, 2]. The
word itself is most likely derived from “carrigan” or “carrageen”, the Irish for Chondrus
crispus or Irish Moss as it is commonly known and was coined in 1820s in Ireland [1]. The
gelling potential of carrageenan was first raised from a scientific perspective in 1819 by
English botanist Dawson Turner, who was studying what he believed to be the brown
seaweed Fucus crispus, in fact it was Chondrus crispus. He wrote “it will melt on boiling and
afterwards harden into a gelatine, which I do not despair of seeing hereafter employed to
useful purposes, though I have hitherto failed in my efforts to render it of service”. Indeed,
Dawson was correct in thinking that there should be some “useful” employment for this
gelling property but most likely would never have conceived that it would one day be a
million-dollar global industry.
Carrageenan is a generic term that is used to describe a diverse group of sulphated
polysaccharide compounds that are found in the cell wall matrix of red seaweeds. These
seaweeds all belong to the order Gigartinales. From a commercial perspective, three main
types of extracted carrageenan are important: iota (ι), kappa (κ) and lambda (λ). Carrageenan
is used extensively to provide textural functionality, primarily for gelling and viscosity in a
wide range of food applications. The primary food sectors are processed meats, dairy and
desserts/jellies (Figure 1). It is also used in tooth paste, pet food, as a flocculating agent in
beer and in some industrial applications e.g., in air freshener gels.
All hydrocolloids have different properties and technical functionalities and hence
different application potential. Carrageenan has a specific set of properties that differentiates
it from other hydrocolloids and renders it useful in certain foods i.e., an ability to form gels
with potassium and calcium ions; reactivity with milk proteins; formation of thermo-
reversible gels and synergistic behaviour with other food hydrocolloids.
Figure 1. Carrageenan sales by end use showing major end use categories; estimated volumes
for 2006, 2011 and 2015 [CyberColloids own data]. NB: Jellies/Conf includes frozen desserts, jellies
and confectionery.
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1.1. Commercially Important Types of Carrageenan
At the broadest level within the food industry, carrageenan is recognised as either
“Carrageenan” or “PES - Processed Eucheuma Seaweed”, although within the industry the
terms “refined” and “SRC” (semi-refined carrageenan) are used to denote these. Under
European legislation “Carrageenan” and “PES” carry food additive numbers E407 and E407a
respectively. The distinction is made on the basis of acid insoluble material content that
results from the different extraction techniques used [3, 4]. E407 carrageenans are refined and
have <2.0% AIM (essentially cellulose) remaining, whereas E407a carrageenans are semi-
refined and still contain most of the AIM content (8-15%). The US FDA also recognises
“carrageenan” and “PES” as permitted for direct addition to food for human consumption in
the Code of Federal Regulations (CFR 21, § 172.620) [5].
From a food texture perspective, carrageenan is classified as either iota (ι), kappa (κ) or
lambda (λ) depending on which seaweed it has been extracted from. Different
carrageenophyte seaweeds variably yield different types and ratios of these carrageenans and
different processing techniques are used to extract them. Some carrageenophytes yield
important “hybrid” mixes, primarily kappa with either iota or lambda [6, 7]. The iota, kappa,
lambda story is somewhat of an oversimplification as, in reality, the source seaweeds contain
a spectrum of types [8] but the major seaweed sources e.g., Kappaphycus and Eucheuma
generally yield ≈ 75% kappa and iota respectively. Specific detail on the sources and
extraction of carrageenan are given by Hotchkiss et al. elsewhere in this book but a brief
summary follows here.
Refined Carrageenan (E407)
Refined kappa, iota and lambda carrageenans are produced using two basic extraction
processes, alcohol precipitation and gel press. Kappa carrageenan is extracted from species of
Kappaphycus (predominantly K. alvarezii but also K. striatum) whereas iota carrageenan is
extracted from Eucheuma denticulatum). Lambda carrageenan is primarily extracted from
Chondrus crispus but also from some high yielding hybrid types (see below). Kappa and iota
carrageenan are converted during processing from their naturally occurring precursors, mu (μ)
and nu (ν) carrageenan respectively. Mu and nu are believed to be the biosynthesis of kappa
and iota [8]. Thus commercial kappa and iota carrageenans are copolymers of kappa:mu and
iota:nu carrageenans respectively. Lambda is actually the precursor and is only partially
converted to theta carrageenan (θ) during processing. Generally only about 10% is converted
(Blakemore pers. comm.) hence the industry refers to this carrageenan as lambda.
The refined carrageenan extraction processes are essentially the same to a point: the dried
seaweed is rinsed and hydrated in fresh water for <4 hours and then treated with hot (80°C)
alkali (potassium hydroxide) to dissolve the seaweed and to convert the precursors. Impurities
are then removed by centrifugation and filtration. At this point the two processes diverge and
different methods are used to separate out the carrageenan. In the alcohol precipitation
process, 60% isopropyl alcohol is used to precipitate out the carrageenan which is then
mechanically pressed to remove excess alcohol and water. This method can be used for all
three types of carrageenan. The gel press technique makes use of the gelling characteristics of
kappa carrageenan only which forms strong brittle gels in the presence of K+ ions. Instead of
a precipitation step, the carrageenan is gelled with potassium chloride and then pressed to
dewater. In both processes the pressed cake is then dried, milled and finished.
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Carrageenans produced using the alcohol precipitation method are purer and have much
of the AIM (acid insoluble matter) removed, they typically contain <0.1% AIM. Gel pressed
kappa carrageenan typically contains <0.5% AIM. Refined iota carrageenan from Eucheuma
has high purity and high clarity. Its main application is in high value products such as
toothpaste. Refined iota has a higher market value than refined, gel press kappa carrageenan,
the market price is often twice that of refined kappa. However, refined kappa carrageenan has
high gel strength and high clarity. It has particular demand in Asia for use in jellies and
desserts. In 2015, the global production of refined carrageenan was estimated in the region of
35,000 tonnes (dry) [CyberColloids own data].
Lambda carrageenan is non-gelling. It is more used for its thickening properties and
because it imparts a creamy texture rather than a typical gel texture. It is mainly used in
desserts to provide creamy texture and mouthfeel.
The hybrid carrageenans (also referred to as “kappa-2-hybrids”, “weak gelling hybrids”
and “heterogenous grades) are extracted from different seaweeds belonging to the family
Gigartinaceae. In the Northern hemisphere, Chondrus crispus and Mastocarpus stellatus and
in South America, primarily Chile, Gigartina skottsbergii (industry name skottsbergii),
Sarcothalia crispata (industry names nama or broadleaf), Mazzaella laminaroides (industry
name narrowleaf) and Chondracanthus chamissoi (industry name chamissoi) (see Figure 2).
The sporophytes of these seaweeds yield kappa-lambda hybrid mixes whereas the
gametophytes yield kappa-iota hybrid mixes.
The base process used to extract these hybrid carrageenans also employs an alkaline
extraction at ≈ 80°C with ≥5% potassium hydroxide but the seaweed slurry is made using
alcohol:water as the solvent and not just water. The alcohol:water serves to keep the
carrageenan from dissolving. Reaction parameters are controlled to promote required
functionality of resultant carrageenans and selective extraction is also employed to target the
individual iota, kappa and lambda components. Temperature, pH and the presence of
potassium chloride are used to manipulate the solubility of different carrageenans [9].
Although this process employs the same strategy as a semi-refined process i.e., the
carrageenan conversion step occurs inside the seaweed (see below), the AIM content of these
hybrid species is naturally low and therefore the end products conform to the E407
specification.
The hybrid carrageenans have particular application in dairy products on account of their
“visco-gelling” properties that provide unique mouthfeel attributes. They characteristically
provide very elastic, soft gels that give thickening without the “gumminess” that other
hydrocolloids give. These attributes are highly desirable to food formulators and current
industry data suggest that the global production of these grades is growing. In 2015, an
estimated ≈ 5000 tonnes (dry) was produced [CyberColloids own data].
Semi-Refined Carrageenan (E407a)
Semi-refined (PES) grades of both kappa and iota carrageenan are produced from
Kappaphycus and Eucheuma respectively. The process begins in the same way as the refined
process, with the seaweed being rinsed, hydrated and treated with hot alkali (<80°C, 5-8%
potassium hydroxide); however, in this case the temperature is kept below 80°C to prevent
the seaweed from dissolving and to keep the conversion of the precursors within the seaweed.
The hot alkali itself and washing steps are used to remove impurities such as minerals,
proteins and fats but there is no precipitation or gelling step to separate out the carrageenan.
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Figure 2. Seaweeds from the order Gigartinales – sources of different carrageenans:
(i, iv) Kappaphycus alvarezii source of kappa carrageenan; (ii) Eucheuma denticulatum source of iota
carrageenan; (iii) Chondrus crispus, source of lambda carrageenan; (v) Sarcothalia crispata hybrid
source and (vi) Mazzaella laminarioides hybrid source [iii by permission R. Jutsum, v and vi by
permission J. Zamorano].
Semi-refined carrageenans are by nature slightly cloudy as the AIM content has not been
removed, however, clarity is not an issue for the key applications in which they are used. SRC
is primarily used in processed meat products, to extend the meat and other sources of protein
and thus add value. Current growth in the carrageenan market as a whole is being driven to a
large extent by an increase in demand for SRC for use in meat products. In 2015 an estimated
24,000 tonnes (dry) SRC was produced [CyberColloids own data].
1.2. Functional Properties of Carrageenan
Each hydrocolloid has its own characteristic intrinsic properties, functional behaviour,
gelling mechanism and nature of the colloidal system that is formed. Each hydrocolloid also
behaves differently under different processing conditions and in different formulations.
Temperature, pH, presence/absence of sugars and salts all affect important parameters such as
solubility and gel stability and thus overall suitability in end applications. Carrageenan is
particularly noted for its ability to form gels in the presence of potassium and calcium ions;
reactivity with milk proteins; formation of thermo-reversible gels and synergistic behaviour
with other food hydrocolloids. Table 1 below gives a summary of the key functional
properties of the different types of carrageenan which are explained in more detail below.
Solubility
Kappa and iota carrageenan molecules need to be heated to solubilise. Once hot the
molecules solubilise forming coils and as cooling occurs the carrageenan strands form helices
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[10]. These helices will aggregate and stick together if K+ or Ca2+ ions are present, such as in
milk or as in the case of gel pressed kappa carrageenan which always contains residual levels
of potassium chloride (1-2%) from the extraction process. Aggregation results in the
formation of a gel. In cold water, kappa and iota molecules tend to swell but lambda
molecules are soluble. Lambda is also soluble in cold milk which has a number of benefits for
application in dairy (see below).
Gelation
Gelling in carrageenan is caused by helix formation and can only occur when a 3, 6
anhydro bridge is present on the B unit of the carrageenan molecule. These anhydro bridges
are not present in the native carrageenan precursors but are created during extraction by the
elimination of sulphate from the sulphate esters that are present in the precursors. Higher 3,6-
AG content and lower ester content results in higher gelling potential. The ester sulphate
content of kappa, iota and lambda carrageenans is approximately 25%, 32% and 35%
respectively [11]. Kappa carrageenan generally has a higher 3,6-AG content than iota
carrageenan. Thus it has high gelling capacity and forms strong, brittle gels with high gel
strength. Iota carrageenan gels are typically softer and more elastic. Kappa-iota hybrids form
somewhat intermediate gels, as the iota component reduces the strength and brittleness of the
kappa component. Pure lambda does not have the necessary 3,6 anhydro bridges to form gels.
Lambda hybrids have weak gelling ability that contributes more to a thickening functionality
than a gelling one.
The ratio of the copolymers in commercial carrageenans is therefore important as the
higher the kappa or iota content, the higher the gel strength. For example, the ratio of
kappa:mu in the seaweed is about 70:30. After extraction in strong alkali, this ratio moves to
95:5, which increases gel strength (Blakemore pers. comm.).
Carrageenan gels in the presence of K+ and/or Ca2+ ions. Kappa gels in the presence of
either, iota gels only in the presence of Ca2+. These ions mediate the aggregation of the
carrageenan helices to form the gel. The strength of the gel formed is dependent on the
concentration of both the carrageenan and K+ and Ca2+ ions that are in solution. The presence
of Ca2+ makes the kappa gel brittle whereas a pure K+ gel is elastic and cohesive [12]. Refined
kappa forms the strongest gels, a 1.2% carrageenan + 0.3% KCl gel will have a gel strength
of >700g/cm2 whereas and equivalent gel using semi refined kappa will have a gel strength in
the region of 400g/cm2. The reason being, the presence of a low percentage of cellulose in the
semi refined gel that causes premature rupturing of the gel during testing.
Thermo reversibility, hysteresis and thixotropy
Kappa and iota carrageenan gels are thermo-reversible i.e., they do not undergo a
permanent change on heating. They also exhibit hysteresis i.e., they have a different gelling
and melting temperature. Both gel on cooling to 40-600C. Iota gels will melt at 5-100C above
and kappa gels at 10-200C above [10]. On cooling they re-gel. This is a particularly useful in
that it allows for several heat cycles to be performed without significant damage to the final
gel strength.
Iota gels are also thixotropic and will reform after mechanical destruction, this property
makes them ideal in applications were cold filling is required e.g., multi-layer desserts [12]
and in products were suspension is required. Both properties are advantageous from a
processing perspective.
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Table 1. Key functional properties of the different types of carrageenan
Kappa (κ)
Iota (ι)
Lambda (λ)
Primarily used for its
gelling ability, has the
highest gelling of the all
the carrageenans.
Primarily used for
softer gels, good freeze
thaw stability.
Primarily used as a
thickener to provide
creamy texture and
mouthfeel in desserts.
 Pros and X Cons

Forms strong, self-
supporting, brittle gels,
gelling is mediated via
K+ or Ca2+ ions

Typically forms softer,
elastic gels but forms
strong gels if fully
converted, gelling is
mediated via Ca2+ ions

Pure sources do not gel,
lambda hybrids form
weak gels more suited
to thickening that
gelling

Heat to solubilise – on
cooling gel forms

Heat to solubilise – on
cooling gel forms

Cold soluble

Gels exhibit hysteresis

Gels exhibit hysteresis

Forms thermo-
reversible gels

Forms thermo-
reversible gels
X
Does not form
thixotropic gels

Forms thixotropic gels
X
Gels have tendency to
form syneresis

Little or no syneresis

Available as clear
(refined) and cloudy
(semi refined) grades

Available as clear
(refined) and cloudy
(semi refined) grades

Only available as
refined grades

Strong protein
interaction

Moderate protein
interaction

Low protein interaction

Strong interaction with
other gums

Good interaction with
kappa

Good mouthfeel and
creaminess
X
Not freeze thaw stable

Good freeze thaw
stability
X
Not freeze thaw stable

Low doses generally
needed, very cost
effective

Low to moderate doses
generally needed,
application dependant
X
Expensive
X Hydrolyses at low pH (<3.5), especially when heated
X ι, κ * λ not acid stable or bake stable
Syneresis
One disadvantage of kappa potassium gels is that they typically have syneresis which
increases over time as the gel contracts. Other hydrocolloids such as xanthan gum and other
galacto/glucomannans be added to kappa carrageenan gels to decrease syneresis. Iota
carrageenan has little or no syneresis. It is an excellent water binder and can be blended with
kappa to reduce or eliminate syneresis [12]. Kappa-iota hybrid grades also have lower
syneresis due to the iota component [13].
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Freeze-Thaw Stability
Kappa carrageenan gels are not regarded as freeze-thaw stable as they completely loose
gel structure and ooze water on thawing. Iota gels however have good freeze thaw stability
and this is one of the key properties that enables application in frozen desserts.
Synergy with Milk Proteins
Kappa carrageenan has strong synergy with milk proteins in particular casein, which
results in the formation of a milk gel. At low doses (100-400ppm) and in the presence of
either Ca2+ or K+, a weak gel network is established that can act as a stabiliser and suspending
agent. Because the kappa-casein interaction reinforces the gel network in milk, the amount of
carrageenan required to form the gel is about 1/5th that required to achieve the same in water
[12]. This is a property which is unique to kappa carrageenan and has allowed for the
development of a niche application in chocolate milk (and more recently some other mineral
fortified milks). Cocoa particles are suspended well in such a network. Both refined and semi
refined kappa [19] can be used. The strong protein reactivity and low dose requirement of
kappa means that it is the most cost effective stabiliser and suspension agent for many dairy
products including chocolate milk. Iota carrageenan has moderate protein reactivity and
lambda has low protein reactivity. Lower protein reactivity gives viscosity rather than a
gelling texture which is also important in dairy based desserts that require “creaminess”. As
with kappa, the amount of lambda required to give viscosity in milk is about 1/10th that
required in a water system [12].
Carrageenan is also used to stabilize non-dairy milk drinks such as soy or almond. The
protein reactivity is not as strong as with casein and in general, the amount of carrageenan
required is proportional to the quality of the protein used (Blakemore pers. comm.). Other
gums such as LBG and gellan are often used in combination with the carrageenan in such
products.
Synergy with Other Gums
Kappa carrageenan interacts with other galactomannan and glucomannan type gums
including LBG (Locust Bean Gum), konjac, xanthan, tara gum and cassia gum to form gels
that are stronger and different in texture to kappa only gels. LBG can be used with kappa to
form gels that approach the texture of gelatin i.e., less brittle and more elastic. LBG increases
the gel break strength and brings cohesiveness and rigidity to the gel. Addition of xanthan
makes a kappa gel softer, more elastic and cohesive. Xanthan also reduces syneresis but a
negative aspect is that kappa xanthan gels tend to trap air bubbles. Kappa carrageenan is not
synergistic with guar [12]. Iota and lambda do not have synergy with these other gums.
This property is widely exploited in the formulation of Asian dessert jellies where, having
a palette of different textures and mouthfeel is essential. Figure 3 below gives a practical
example of how different Asian dessert jellies are formulated for specific organoleptic
qualities using different ratios of kappa carrageenan and konjac.
An important non-food area where the synergy of carrageenan, particularly iota, with
starch is exploited, is in the production of vegetarian films (i.e., non gelatin) for capsule
production. This whole area has interesting possibilities for the production of edible coatings
and films for other purposes such as packaging, carriers for actives and to extend shelf life
[14].
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1.3. Key Application Areas for Carrageenan
As clearly shown in Figure 1, the key application areas for carrageenan are in (i)
processed meats; (ii) dairy and (iii) desserts and jellies. With its specific set of functional
properties (as outlined above) it is not difficult to see why application is most suited to these
areas. The different gelling and thickening properties of the iota, lambda and kappa grades
gives good flexibility across a number of application sectors and also within product areas
that require many different textures e.g., dairy desserts. Reactivity with milk protein gives
kappa an unbeatable edge in terms of cost when used in chocolate milk and ice cream and the
ability to use SRC in meats and dairy also brings cost benefits. The focus of the next section
will be on the uses of carrageenan in these key areas however, it must be noted that
carrageenan has application in a wider range of food products, but to a far lesser degree,
including infant formula, different dairy products, yogurts, soft chesses and cheese analogues,
dressings, syrups, fruit preps and jams [10, 19].
Figure 3. Commercial example of how the synergistic properties of kappa carrageenan and konjac can
be used to produce Asian dessert jellies with specific organoleptic qualities. By manipulating the ratio
of carrageenan:konjac a full range of textures can be achieved [By permission of Teejoy Marine SBN
BHD].
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Processed Meat Applications
Carrageenan is used in processed meat applications for the following key reasons: (i)
increased yield; (ii) improved texture; (iii) as a processing aid and (iv) for appearance. Semi
refined kappa carrageenan is used most as the added benefits of using refined grades (clarity,
purity) are not essential and also the higher cellulose content is beneficial in some
applications [19]. Iota carrageenan can also be used but lambda is typically not used.
Meat based products are generally expensive and a number of strategies are employed to
add value and to improve yields as even a small increase in yield can have a significant
impact on cost for producers. Products made from comminuted meat (burgers, nuggets),
reformed meats (hams, chicken rolls) and emulsions (frankfurters and sausages) are cheaper
to make than products using whole meat muscle. A range of other ingredients such as
hydrocolloids, fibres and cheaper protein sources are added as extenders and binders and thus
to reduce cost [15]. Carrageenan is one of the major hydrocolloids used and growth in
demand for SRC in particular is a key driver in the growth of the carrageenan market as a
whole.
The organoleptic qualities of meat products are vital, especially in processed meat
products where perceived texture e.g., bite, juiciness and tenderness are of utmost importance
to the consumer. The water binding functionality of carrageenan plays a key role here and
because a variety of textures can be achieved with carrageenan, then a range of textures can
be created as appropriate for the end product. Water binding also serves to improve important
attributes such as cookloss and purge, which not only affect the appearance of cooked and
uncooked products but have significant cost implications for producers.
Ham, chicken and turkey products are a major sector where carrageenan is used. Water
management in such products is vital especially when highly extended. Products should retain
the added brine during processing in order to make the end products juicy and easy to slice
with little breakages. As all three types are marketed in pre-sliced forms, this has significant
implications for producers both in terms of processing efficiency and cost. Carrageenan is
incorporated into the brines that are used in the production of processed meats, either during
the tumbling stage of reformed products or into the injection brines that are used for whole
muscle products (particularly hams).
Semi refined carrageenan has found particular application in hams that are injected with
brine. The process can lead to the development of unsightly strips of gel known a “tiger
striping”. This can be significantly reduced or overcome through the use of semi refined
carrageenan which swells less during injection due to the presence of cellulose in the matrix
[16, 17]. An additional benefit is that the carrageenan also does not block the injection
nozzles that are used because of the lower cold swelling capacity [19].
Ice cream
Carrageenan is used in ice cream as a stabilizing agent and processing aid. A crucial
aspect of ice cream production is achieving a homogenous mix to feed into the ice cream
machine. Before Kappa grades are typically used, both refined and semi refined, and most
likely blends of these. Other gums are also used in the formulation e.g., LBG and guar, LBG
to retard the meltdown of ice cream and guar to thicken the mixture. In general, a thicker ice
cream mix results in slower meltdown and better shape retention [18]. However, the addition
of LBG and guar forces serum separation in the mix. Carrageenan is added at a very low
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dosage (100-400ppm typical) to prevent this. The low dose is very cost effective and has no
impact on the viscosity of the mix or the texture of the end product.
Chocolate Milk and Milk Based Drinks
Carrageenan is used in chocolate and other milk drinks (see Figure 4) primarily as a
thickening and suspension agent but the thickening functionality also provides mouthfeel.
Refined and semi refined kappa grades are normally used. The negatively charged
carrageenan molecules interact with the positively charged casein proteins in the milk to form
weak gel network that allows the cocoa particles to be suspended. Additional carrageenan-
carrageenan interactions (due to the helical formation) and carrageenan-Ca-carrageenan
crosslinkages also contribute. Carrageenan is added at very low dosage (100-400ppm typical)
and thus is a very cost effective suspension agent.
Carrageenan is similarly used to stabilize and thicken infant formulations. The safe use of
carrageenan in this specific application area was evaluated by the 79th meeting of FAO/WHO
Joint Expert Committee on Food Additives (JECFA) who concluded that “the use of
carrageenan in infant formula or formula for special medical purposes at concentrations up
to 1000 mg/L is not of concern”.
Dairy Desserts
A wide array of dairy desserts is found in the market including puddings, flans, mousses,
custards and multi-layered confections. Dairy desserts therefore can be creamy and spoonable
to firm and rigid (Figure 4). Also, different regions and cultures all have very different
expectations as to the appropriate texture of each of these. The French market in particular
has high demand and diversity of products that utilise carrageenan. Carrageenan is used in
such desserts because the variable texture properties of iota, kappa and lambda grades make it
a highly versatile texture agent. This is one area in which the lambda carrageenans and hybrid
grades excel as the lambda component imparts a creamy texture with mouthfeel that is typical
of many dairy desserts. Lambda is often considered the gold standard, particularly in low fat
products that require the use of fat mimetic functionality. In addition, the particular gel
properties and protein reactivities of the commercial hybrid carrageenans cannot be
reproduced by combinations of commercial kappa and iota carrageenans, hence their demand
is also high this area. Carrageenan functions well under the typical processing conditions used
to produce dairy desserts. It can be added to the milk before processing, solubilises during
heating (pasteurisation/UHT) and then gels or thickens on cooling.
(i)
(ii)
(iii)
Figure 4. (Continued)
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(iv)
(v)
(vi)
Figure 4. Typical applications where carrageenan is used: (i) suspension in chocolate milk; water
binding in processed meats; (iii) prevention of serum separation in ice cream; (iv) texture and mouthfeel
in dairy desserts; (v) texture and extension in processed cheese (vi) variety of gel textures in dessert
jellies.
Dessert Jellies
The major end use for gel press refined kappa carrageenan is in dessert jellies (Figure 4),
predominantly for the Asian market. Carrageenan is typically used in combination with other
gums such as LBG or konjac. Combined use with other gums allows for a wider spectrum of
jelly textures and mouthfeel to be created.
In dessert jellies, carrageenan is well known for its excellent clean flavour release unlike
some other gums (xanthan, guar) that can impair flavour performance. It can also impart
juiciness which is often required in fruit flavoured desserts. Carrageenan is not stable in hot
acid conditions for extended periods so some care has to be taken to add any acidic
ingredients immediately prior to cooling. Once cool, carrageenan is stable under acidic
conditions due to being in helical conformation.
Pet Food
One of the significant non-food sectors in the global carrageenan market (Figure 1) that
utilises SRC. Historically, different grades of SRC have been used for application in pet food.
Lower quality grades with less stringent microbial and colour specifications were used for pet
food. Nowadays pet food grades are subject to HACCP safety protocols and there is very little
difference in the grades used.
A typical canned pet food product uses a stabiliser/processing aid/gelling formulation
which contains SRC kappa with LBG or cassia gum, phosphates, salts, sugars and sometimes
added minerals or vitamins. The carrageenan has two main functions, as a retort stable gelling
agent and stabiliser, Retorted pet foods are processed in the can @ >135°C, during which, the
carrageenan and other gums are dissolved but form a gel on cooling. Leaching of blood from
the meat into the gel during cooking is prevented by the addition of carrageenan which acts as
a stabiliser. Carrageenan is also used in other types of pet food formulations such as single
serve pouches for cats and also premium gravy type (non-gel) products and more recently in
chewable snacks where it provides binding and texture functionality.
Toothpaste
Refined iota carrageenan has a niche application in toothpaste (Figure 1). The weak
gelling and water binding properties make it ideal thickener. It is also stable against
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enzymatic degradation, has good flavour release and rinse-ability which are key attributes for
toothpaste [12].
1.4. A Word on Regulatory and Carrageenan Specifications
Carrageenan is typically used in foods at a very low dose (0.1-2%) [1] nonetheless, both
refined carrageenan and PES are approved by the Joint FAO/WHO Expert Committee on
Food Additives (JECFA) and are assigned an ADI of “not specified” At the 57th meeting, the
JECFA committee concluded that intakes of both carrageenan and PES in line with their use
as food additives was of no safety concern. More recently, in 2015, the 79th committee also
concluded that the use of carrageenan in infant formula or for special medical purpose at
concentrations of 1000mg/l is also of no concern [18]. Also, the US Food and Drug
Administration maintain that the level at which carrageenan is used in foods to achieve
functionality is safe and that no upper limit needs to be established [5].
Despite these recommendations, there is an ongoing debate about the safety of
carrageenan that hinges on the fact that poligeenan, a low molecular weight sulphated
polysaccharide that is produced through very aggressive hydrolysis of carrageenan (95°C and
pH 1.0 for up to 6h) and at one time referred to as “degraded carrageenan” is considered a
carcinogen. Poligeenan has a very low molecular weight of 10-20kDa and is used solely for
medical imaging and should not be confused with commercial carrageenan that is used in
food. The average molecular weight range of carrageenans used in food is ≈ 400-600kDa [2].
The viscosity of pure carrageenans must be greater than 5cps. As viscosity is related to
molecular weight this compendial specification, a simple and easy test which is carried out at
a concentration of 1.5% at 75°C, achieves the objective to limit the lower molecular weight
content of commercial carrageenan.
Carrageenan is not always sold pure but is often blended with other ingredients. This is
generally done to aid processing e.g., blending with sugar can aid dispersion and also for
standardisation purposes e.g., a chocolate milk grade with specific gel strength and
functionality. Legally any diluents should be listed in the product specification, however if
the ingredient is present as residual from processing e.g., KCl in gel press kappa, then no
declaration is needed.
CONCLUSION
Elsewhere in this book, CyberColloids has presented industry information on the size and
shape of the carrageenan market. During the period 2006 to 2015, annual global production of
carrageenan is estimated to have risen in the region of 8,000 tonnes (dry) which very
approximately equates to an additional 230,000 tonnes of wet seaweed per year. Significant
growth has occurred in the production of SRC, gel press and hybrid grades.
The rise in demand for SRC is primarily being driven by growth in the processed meats
markets and to lesser degree dairy applications including chocolate milk. The growing
demand for processed food is a global trend, being driven by opposing changes in the world’s
economies. On one side, recession is forcing consumers to seek value for money, on the
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other, improved standards of living and emerging economies are enabling consumers to look
for more diverse product offerings. From either perspective carrageenan is a winner and
growth in its production is expected to continue.
One aim of this chapter was to demonstrate that carrageenan is a multifunctional
ingredient with potential for application in a wide range of different foods. What really
distinguishes it from other hydrocolloids is an ability to provide gelling, thickening and
stabilisation functionality in milk as well as water based formulations; in particular, the
reactivity with milk proteins to give additional stabilization functionality. This is evidenced
by the fact that dairy applications are a significant end market use for carrageenan and also by
the development of niche sectors for the different carrageenans within the wider dairy market.
In the case of kappa, strong protein reactivity means that it has very low dose requirement and
is therefore an extremely cost effective stabiliser and suspension agent for many applications.
For iota, the key properties are moderate protein reactivity coupled with freeze-thaw stability
and the formation of soft gels. In the case of lambda and lambda hybrid grades, the creamy
textures and mouthfeel attributes afforded by the visco-gelling properties are quite unique.
The diverse range of properties and textural attributes that the different carrageenans
bring to food are factor of the diverse nature of the different grades themselves. We have
described how a full spectrum of gelling textures can be achieved by manipulating the gelling
environment, dosage and presence (or not) of other synergistic ingredients. In Asian markets
in particular, this spectrum of textures is highly valued. Here, the dessert jellies market is
essentially serviced by the production of gel pressed kappa carrageenan and takes a
significant proportion of the global production.
Carrageenan is the leading seaweed derived food hydrocolloid and currently has fourth
largest share of the global food texture market (in terms of value), behind starches, gelatine
and pectin. In terms of future developments and potential new areas of market growth: there
have been interesting developments in the use of carrageenan in the health and pharma sectors
in recent years (covered in detail elsewhere in this book) and, the development of edible films
for food preservation and packaging could provide some innovative developments in the food
sector. Of course the “holy grail” of gelatin replacement is still a hot topic in the
hydrocolloids world. Carrageenan is well promoted as a domestic substitute for gelatin along
with agar and can be used commercially to achieve some of the properties and functionality
of gelatin. The real commercial challenge is of course to achieve the “melt in the mouth”
attribute that sets gelatin apart. As yet SRC has not made significant inroads into the dairy
dessert market, this is potentially an area where we could see some future innovation for the
carrageenan food industry.
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