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İçindekiler
1. EXPLANATION....................................................................................................................... 2
1.1 Chemical and technical considerations .......................................................................... 2
2. BIOLOGICAL DATA ................................................................................................................ 3
2.1 Biochemical aspects ....................................................................................................... 3
2.2 Toxicological studies ...................................................................................................... 4
2.2.1 Acute toxicity .......................................................................................................... 4
2.2.2 Short-term studies of toxicity ................................................................................. 4
2.2.3 Long-term studies of toxicity and carcinogenicity .................................................. 6
2.2.4 Genotoxicity ............................................................................................................ 6
2.3 Observations in humans ................................................................................................ 6
3. DIETARY EXPOSURE .............................................................................................................. 6
3.1 Use in foods.................................................................................................................... 7
3.2 Dietary exposure estimates ........................................................................................... 7
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1. EXPLANATION
At the request of the Codex Committee on
Food
Additives
at
its
fortieth
session
(FAO/WHO, 2008), the Committee evaluated
cassia gum, which it had not evaluated
previously. Cassia gum is related to guar gum,
locust (carob) bean gumand tara gum in terms
of structure and chemical properties. The
galactomannans of guar gum, locust (carob)
bean gum and tara gum have mannose to
galactoseratios of 2:1, 4:1 and approximately
3:1, respectively. Each of these three gums was previously allocated an
acceptable daily intake (ADI) “not specified”
1.1 Chemical and technical considerations
Cassia gum is the purified flour from the endosperm of the seeds of Cassi
tora and Cassia obtusifolia, which belong to the Leguminosae family. Cassia
gum is composed of at least 75% high relative molecular mass
(approximately200 000–300 000) polysaccharide, consisting primarily of a
linear
chain
of
1,4-�-Dmannopyranoseunits
with
1,6-linked
�-D-
galactopyranose units. The saccharides are composed of mannose (77.2–
78.9%), galactose (15.7–14.7%) and glucose (7.1–6.3%). The ratio of
mannose to galactose is 5:1.The manufacture of cassia gum includes
cleaning of the source material, by which the content of Cassia occidentalis
(which is a naturally occurring contaminant)is reduced to less than 0.05%,
de-husking and de-germing by thermal mechanical treatment, followed by
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milling and screening of the endosperm. The ground endosperm is further
purified by extraction with isopropanol. The concentration of anthraquinones
in cassia gum is below the 0.5 mg/kg detection limit. The food additive under
evaluation is cassia gum that is refined and complies with the specifications
established at the current meeting.Cassia gum is used as a thickener,
emulsifier, foam stabilizer, moisture retention agent and/or texturizing agent
in processed cheese, frozen dairy desserts and mixes, meat products and
poultry products.
2. BIOLOGICAL DATA
2.1 Biochemical aspects
No specific absorption, distribution, metabolism or excretion data were
available on the galactomannans from cassia gum. However, from studies on
guar gum, locust (carob) bean gum and tara gum reviewed by the Committee
at its nineteenth, twenty-fifth and thirtieth meetings, respectively (Annex 1,
references 39, 57 and 74), it appears that other galactomannans in related
gums undergo no or only minimal hydrolysis by digestive juices or enzymes,
independent of the specific mannose to galactose ratio. They can be partially
fermented by large gut microflora, but are largely excreted unchanged in
faeces. The Committee concluded that cassia gum will be largely excreted
unchanged as well, although fermentation by gut microflora may occur to
some
extent.
If
hydrolysis
of
cassia
gum
occurs,
the
resulting
oligosaccharides or monosaccharides would be expected to be absorbed and
metabolized in normal biochemical pathways.
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2.2 Toxicological studies
Most available toxicological studies were performed with semi-refined cassia
gum. Semi-refined cassia gum is produced similarly to the cassia gum
currently
under evaluation, with the exception of an additional isopropanol extraction
step to significantly reduce the level of anthraquinones in the latter.
Anthraquinones are impurities that occur naturally in the seeds from which
cassia gum is produced, some of which may display muscle-toxic, genotoxic
or carcinogenic properties. Semi-refined cassia gum contains approximately
70 mg total anthraquinones/kg.
2.2.1 Acute toxicity
Two studies of acute oral toxicity were available. In a limit test, five male
Wister-Han-Schering rats were given in total 5000 mg semi-refined cassia
gum/kg body weight (bw) by oral gavage in two doses at a 2-h interval. The
oral median lethal dose (LD50 value) in this study was >5000 mg/kg bw. The
study was certified for compliance with Good Laboratory Practice (GLP) and
quality assurance (QA) (Schobel, 1986). In another limit test, 10 male and 10
female KM mice were given in total 10 000 mg cassia gum/kg bw by oral
gavage in four doses over 24 h. The oral LD50 value in this study was >10 000
mg/kg bw. Statements regarding compliance with GLP and QA were lacking
(Weidu, 2006).
2.2.2 Short-term studies of toxicity
In a 28-day study of toxicity (Zuhlke, 1990), groups of five male and five
female Crl:CD (SD)BR Sprague-Dawley rats (aged 5–6 weeks) were
administered semi-refined cassia gum at dietary concentrations of 0, 2500,
10 000, 25 000 or 50 000 mg/kg feed (equal to doses of 0, 250, 1030, 2590
and 4960 mg/kg bw per day for males and 0, 230, 1110, 2360 and 4590
mg/kg bw per day for females). A sixth group received semi-refined cassia
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gum by gavage (in distilled water) 2 times a day, at a total dose of 1000
mg/kg bw per day. The study was certified for compliance with GLP and QA
and was essentially performed as described in Organisation for Economic
Co-operation and Development (OECD) Test Guideline
407 (Repeated Dose 28-day Oral Toxicity Study in Rodents), although
weekly detailed clinical investigations and measurements of sensory
reactivity were omitted. Observations included mortality, clinical signs,
behaviour, body weight, food consumption, haematology, clinical chemistry,
organ weights (adrenals, brain, heart, kidneys, liver, ovaries and testes),
macroscopic examination and histopathology (on major organs of the
animals in the control group, the 50 000 mg/ kg feed group and the group
treated by gavage). Five animals died during the experiment, but these
deaths were incidental or due to an intubation error or blood sampling
procedure and were not accompanied by signs of systemic target organ
toxicity. No clinical changes that could be attributed to the treatment were
observed. Body weight gain was statistically significantly reduced (–20%) in
males of the 50 000 mg/kg feed group, possibly related to a small (–11%)
decrease in food intake in these animals. In females, body weight gain was
statistically significantly reduced (–17%) in the 10 000 and 25 000 mg/kg feed
group and in the 1000 mg/kg bw per day group.
These changes are considered to be related to the viscous nature of cassia
gum and not considered to be of toxicological relevance. Haematology and
clinical chemistry findings included several statistically significant changes
that for the most part were small, were not dose related or occurred in one
sex only. They were also claimed to be within the normal range for the
species tested, but historical control data were not provided. The only
changes that were outside the historical control range and could have been
related to treatment were increased mean concentrations of glucose and
triglyceride in both sexes of the 10 000 mg/kg feed group (males 41% and
149% and females 56% and 46%, respectively) and 25 000 mg/kg feed
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group (males 53% and 168% and females 74% and 67%, respectively).
These findings were not dose related, however, as they were not observed in
the 50 000 mg/kg feed group or in the group treated by gavage.(Virat, 1984).
2.2.3 Long-term studies of toxicity and carcinogenicity
No information was available for cassia gum. In a limited long-term study of
toxicity with guar gum reviewed by the Committee at its nineteenth meeting
(Annex 1, reference 39), no adverse effects were observed in rats
administered guar gum at a dietary concentration of 5% for 24 months. In
carcinogenicity studies reviewed by the Committee at its twenty-fifth and
thirtieth meetings (Annex 1, references 57 and 74), no significant adverse
effects were observed in rats and mice administered locust (carob) bean gum
or tara gum at dietary concentrations up to 5% for 103 weeks.
2.2.4 Genotoxicity
The results of five studies of genotoxicity in vitro with cassia gum and/or
semi-refined cassia gum (three bacterial reverse mutation assays, one
chromosomal aberration assay and one gene mutation assay) are
summarized in
2.3 Observations in humans
The only human data available relate to hypersensitivity or allergenicity.
Studies in industrially exposed and pharmaceutical workers showed that
Cassia and cassia powder may act as sensitizers following dermal and
inhalatory exposure (Satheesh et al., 1994; Steget et al., 1999). No
information is available on food allergies or food intolerance following oral
intake in humans.
3. DIETARY EXPOSURE
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3.1 Use in foods
Cassia gum is used as a thickener, emulsifier, foam stabilizer, moisture
retention agent and/or texturizing agent in processed cheese, frozen dairy
desserts and mixes, meat products and poultry products. Maximum use
levels for cassia gum range from 2500 mg/kg food in frozen desserts and
3000 mg/kg food in cheeses to 3500 mg/kg food in meat and poultry products
(Lubrizol, 2008). In a submission to the European Commission, use levels for
cassia gum only up to 2500 mg/kg food were considered, with a maximum of
1500 mg/kg food for processed meat and poultry products (European Food
Safety Authority, 2006).
3.2 Dietary exposure estimates
The Committee received an assessment of dietary exposure to cassia
gumand additionally accessed data on dietary exposure from the European
Food Safety Authority (EFSA) web site.
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