Lecture
3.9. Toxicology of food stabilisers, thickeners,
complexing agents and gelling agents
One of the important characteristics of a food product, together with colour, aroma and taste, is its consistency. Products are often colloidal systems: emulsions, foams, suspensions. Their formation requires
substances possessing certain properties: surface activity or
the ability to thicken heterogeneous systems. As emulsifiers and stabilisers,
sodium and calcium lactates, mono- and diglycerides of fatty acids, brominated oil (E443), and sucrose isobutyrate are preferably used
(E444). The additive (E443) has not received absolute approval status in
Ukraine [2, 5].
Also used as emulsifiers, stabilisers and thickeners are
oat gum (E411), guar gum (E412), tragacanth (E413), gum arabic
(E414), xanthan gum (E415), karaya gum (E416), tara gum
(E417), gellan gum (E418), ghatti gum (E419), methylcellulose
(E461), ethylcellulose (E462), hydroxypropyl cellulose (E463), hydroxypropyl methylcellulose (E464), methylethylcellulose (E465), the sodium salt of
carboxymethylcellulose (E466), ethylhydroxyethylcellulose (E467), carbulose (without an E index). Additives with the
indices E419, E463, E464, E465, E467 have not received approval status in Ukraine.
There is a known approach among international experts who regard as food
60
additives certain natural substances contained in food products. Indeed,
among the ingredients used in preparing food products, natural dietary fibres are used: pectins, agar, gum.
Such dietary fibres, besides their technological function, possess biological activity. The well-known properties of pectins are to bind in the digestive tract and
remove from the human body salts of heavy metals and radionuclides, and to stimulate human intestinal peristalsis. Artificial dietary fibres, such as
carboxymethylcellulose, are usually dehydrated. They have no positive
effect on the state of the human intestinal microflora and are capable of absorbing and removing from the body useful food substances, for example mineral elements. Practically all types of cellulose are not absorbed in the intestine, but
a certain quantity of them undergoes hydrolysis in the digestive tract.
For various types of cellulose that are recognised as relatively harmless:
hydroxypropyl cellulose, hydroxypropyl methylcellulose, methylcellulose,
sodium carboxymethylcellulose and ethylcellulose, the ADI has been set at
30 mg/kg of body weight. For some food additives – agar, certain gums – «unlimited amounts» of oral intake are permitted
in the human body. However, in Germany tara gum is not permitted for use in food products, and ghatti gum has not received approval status in Ukraine.
Much attention is devoted to the use of modified starches. It has been shown that once or repeatedly modified starches
do not differ significantly in their biological action on the body. These substances
are well absorbed. They have no negative effect on the function of the systems and organs when used in moderate amounts. Provided that their content in food
exceeds 10%, they cause diarrhoea and dilation of the caecum. This
is regarded as a normal physiological reaction of the body to the consumption
of food with a high starch content.
The Joint FAO/WHO Expert Committee on Food Additives recommended the unrestricted use of only enzymatically treated
starches. Other types of chemically treated (modified) starches require further study. This concerns primarily
phosphated hydroxypropyl starch. WHO documents contain data showing that when introduced
into the diet of rats at 5 to 25% chemically modified starches cause
kidney lesions. The severity of the lesion depends
on the amount of substance consumed. On the basis of these data, conclusions have been drawn
about the need for further study of these phenomena and research into their pathogenesis. In the report of the Joint FAO/WHO Expert Committee on Food
Additives, it is indicated that the acceptable daily intake of modified starches,
previously recommended for a number of modified starches as «unlimited», is now regarded as «not specified».
Ethylcellulose (E462) – the ethyl ester of cellulose – has not received absolute approval status in Ukraine, Russia and most countries of the European Union, except Germany. The emulsifier
61
sodium dioctyl sulfosuccinate (E480) has not received approval status in Ukraine. In Ukraine and Germany
the colour stabiliser polyvinylpyrrolidone (E1202) is also prohibited,
although it is permitted in the countries of Europe and Russia.
In sausage production, phosphate is widely used – sodium mono-, di-, tri-, and tetrasubstituted sodium pyrophosphate.
These salts have the property of increasing the water-binding capacity
of sausage meat. Such compounds, in the course of preparing the meat and heat
treatment of sausages, are partially hydrolysed to orthophosphates, which are the only
phosphate present in meat. Tripolyphosphates are most capable of hydrolysis (up to 90%).
Phosphates do not affect the intensity of colour of sausages.
The limiting indicator of the safety of this group of compounds is the state
of kidney function. In the kidneys, signs of calcification may be observed as a result of the additional introduction of phosphates with food. This has a negative effect on
kidney function. On this basis, the Joint FAO/WHO Expert Committee
recommended using phosphates in meat product technology
in an amount not exceeding 0.5% of the mass of meat (calculated as phosphoric anhydride).
Comments