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标题: 二氧化钛(钛白粉) [打印本页]

作者: 1123456789 时间: 2008-5-23 12:09
标题: 二氧化钛(钛白粉)
二氧化钛(钛白粉)

CAC关于二氧化钛(钛白粉)的使用规定
GSFA Online
Food Additive Details
Titanium Dioxide (171)
Number Food Category
  01.1.2 Dairy-based drinks, flavoured and/or fermented (e.g., chocolate milk, cocoa, eggnog, drinking yoghurt, whey-based drinks)
  01.3 Condensed milk and analogues (plain)
  01.4.3 Clotted cream (plain)
  01.4.4 Cream analogues
  01.5 Milk powder and cream powder and powder analogues (plain)
  01.6 Cheese and analogues
  01.7 Dairy-based desserts (e.g., pudding, fruit or flavoured yoghurt)
  01.8 Whey and whey products, excluding whey cheeses
  02.2.1.2 Margarine and similar products
  02.2.1.3 Blends of butter and margarine
  02.2.2 Emulsions containing less than 80% fat
  02.3 Fat emulsions maily of type oil-in-water, including mixed and/or flavoured products based on fat emulsions
  02.4 Fat-based desserts excluding dairy-based dessert products of food category 01.7
  03.0 Edible ices, including sherbet and sorbet
  04.1.2 Processed fruit
  04.2.2.2 Dried vegetables (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera), seaweeds, and nuts and seeds
  04.2.2.3 Vegetables (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera) and seaweeds in vinegar, oil, brine, or soy sauce
  04.2.2.4 Canned or bottled (pasteurized) or retort pouch vegetables (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera), and seaweeds
  04.2.2.5 Vegetable (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera), seaweed, and nut and seed purees and spreads (e.g., peanut butter)
  04.2.2.6 Vegetable (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera), seaweed, and nut and seed pulps and preparations (e.g., vegetable desserts and sauces, candied vegetables) other than food category 04.2.2.5
  04.2.2.8 Cooked or fried vegetables (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera), and seaweeds
  05.0 Confectionery
  06.3 Breakfast cereals, including rolled oats
  06.4.3 Pre-cooked pastas and noodles and like products
  06.5 Cereal and starch based desserts (e.g., rice pudding, tapioca pudding)
  06.6 Batters (e.g., for breading or batters for fish or poultry)
  06.7 Pre-cooked or processed rice products, including rice cakes (Oriental type only)
  06.8 Soybean products (excluding soybean products of food category 12.9 and fermented soybean products of food category 12.10)
  07.0 Bakery wares
  08.2 Processed meat, poultry, and game products in whole pieces or cuts
  08.3 Processed comminuted meat, poultry, and game products
  08.4 Edible casings (e.g., sausage casings)
  09.3 Semi-preserved fish and fish products, including mollusks, crustaceans, and echinoderms
  09.4 Fully preserved, including canned or fermented fish and fish products, including mollusks, crustaceans, and echinoderms
  10.2.3 Dried and/or heat coagulated egg products
  10.3 Preserved eggs, including alkaline, salted, and canned eggs
  10.4 Egg-based desserts (e.g., custard)
  11.6 Table-top sweeteners, including those containing high-intensity sweeteners
  12.2.2 Seasonings and condiments
  12.3 Vinegars
  12.4 Mustards
  12.5 Soups and broths
  12.6 Sauces and like products
  12.7 Salads (e.g., macaroni salad, potato salad) and sandwich spreads excluding cocoa- and nut-based spreads of food categories 04.2.2.5 and 05.1.3
  12.8 Yeast and like products
  12.9 Protein products
  12.10 Fermented soybean products
  13.3 Dietetic foods intended for special medical purposes (excluding products of food category 13.1)
  13.4 Dietetic formulae for slimming purposes and weight reduction
  13.5 Dietetic foods (e.g., supplementary foods for dietary use) excluding products of food categories 13.1 - 13.4 and 13.6
  13.6 Food supplements
  14.1.1.2 Table waters and soda waters
  14.1.4 Water-based flavoured drinks, including "sport," "energy," or "electrolyte" drinks and particulated drinks
  14.2.1 Beer and malt beverages
  14.2.2 Cider and perry
  14.2.4 Wines (other than grape)
  14.2.5 Mead
  14.2.6 Distilled spirituous beverages containing more than 15% alcohol
  14.2.7 Aromatized alcoholic beverages (e.g., beer, wine and spirituous cooler-type beverages, low alcoholic refreshers)
  15.0 Ready-to-eat savouries
  16.0 Composite foods - foods that could not be placed in categories 01 – 15

部分译文：

食品添加剂通用规则
食品添加剂
                  二氧化钛（171）
食品类别：
06.3 早餐谷类,包括燕麦片
06.4.3面条及类似产品
06.5 谷类,淀粉甜点(包括:米粉布丁,木薯布丁)
06.6 面团
06.7 预煮的或加工的米产品,包括年糕(只包括中式的)06.8 Soybean products
07.0 烘焙类
07.1 面包,普通烘焙类,以及其混合物
07.1.1 面包,面包卷
07.1.1.1 酵母发酵面包及特殊面包
07.1.1.2 苏打面包

作者: 1123456789 时间: 2008-5-23 12:10
标题: 二氧化钛（钛白粉）
二氧化钛（钛白粉）

JECFA关于二氧化钛（钛白粉）的结论

摘要： 2006年JECFA关于二氧化钛的结论
ADI值：不作限制。
功能：着色剂

TITANIUM DIOXIDE
Prepared at the 67th JECFA (2006) and published in FAO JECFA
Monographs 3 (2006), superseding specifications prepared at the 63rd
JECFA (2004) and published in FNP 52 Add 12 (2004) and in the
Combined Compendium of Food Additive Specifications, FAO JECFA
Monographs 1 (2005). An ADI “not limited” was established at the 13th
JECFA (1969).
SYNONYMS
Titania, CI Pigment white 6, CI (1975) No. 77891, INS No. 171
DEFINITION
Titanium dioxide is produced by either the sulfate or the chloride
process. Processing conditions determine the form (anatase or rutile
structure) of the final product.
In the sulfate process, sulfuric acid is used to digest ilmenite (FeTiO3)
or ilmenite and titanium slag. After a series of purification steps, the
isolated titanium dioxide is finally washed with water, calcined, and
micronized.
In the chloride process, chlorine gas is reacted with a titaniumcontaining
mineral under reducing conditions to form anhydrous
titanium tetrachloride, which is subsequently purified and converted to
titanium dioxide either by direct thermal oxidation or by reaction with
steam in the vapour phase. Alternatively, concentrated hydrochloric
acid can be reacted with the titanium-containing mineral to form a
solution of titanium tetrachloride, which is then further purified and
converted to titanium dioxide by hydrolysis. The titanium dioxide is
filtered, washed, and calcined.
Commercial titanium dioxide may be coated with small amounts of
alumina and/or silica to improve the technological properties of the
product.
C.A.S. number 13463-67-7
Chemical formula TiO2
Formula weight
79.88
Assay
Not less than 99.0% on the dried basis (on an aluminium oxide and
silicon dioxide-free basis)
DESCRIPTION
White to slightly coloured powder
FUNCTIONAL USES
Colour
CHARACTERISTICS
IDENTIFICATION
Solubility (Vol. 4)
Insoluble in water, hydrochloric acid, dilute sulfuric acid, and organic
solvents. Dissolves slowly in hydrofluoric acid and hot concentrated
sulfuric acid.
Colour reaction
Add 5 ml sulfuric acid to 0.5 g of the sample, heat gently until fumes of
sulfuric acid appear, then cool. Cautiously dilute to about 100 ml with
water and filter. To 5 ml of this clear filtrate, add a few drops of
hydrogen peroxide; an orange-red colour appears immediately.
PURITY
Loss on drying (Vol. 4) Not more than 0.5% (105°, 3 h)
Loss on ignition (Vol. 4)
Not more than 1.0% (800o) on the dried basis
Aluminium oxide and/or
silicon dioxide
Not more than 2%, either singly or combined
See descriptions under TESTS
Acid-soluble substances Not more than 0.5%; Not more than 1.5% for products containing
alumina or silica.
Suspend 5 g of the sample in 100 ml 0.5 N hydrochloric acid and
place on a steam bath for 30 min with occasional stirring. Filter
through a Gooch crucible fitted with a glass fibre filter paper. Wash
with three 10-ml portions of 0.5 N hydrochloric acid, evaporate the
combined filtrate and washings to dryness, and ignite at a dull red
heat to constant weight.
Water-soluble matter
(Vol. 4)
Not more than 0.5%
Proceed as directed under acid-soluble substances (above), using
water in place of 0.5 N hydrochloric acid.
Impurities soluble in 0.5 N
hydrochloric acid
Antimony Not more than 2 mg/kg
See description under TESTS
Arsenic Not more than 1 mg/kg
See description under TESTS
Cadmium Not more than 1 mg/kg
See description under TESTS
Lead
Not more than 10 mg/kg
See description under TESTS
Mercury (Vol. 4) Not more than 1 mg/kg
Determine using the cold vapour atomic absorption technique. Select a
sample size appropriate to the specified level
TESTS
PURITY TESTS
Impurities soluble in 0.5 N
hydrochloric acid
Antimony, arsenic,
cadmium and lead
(Vol.4)
Transfer 10.0 g of sample into a 250-ml beaker, add 50 ml of 0.5 N
hydrochloric acid, cover with a watch glass, and heat to boiling on a
hot plate. Boil gently for 15 min, pour the slurry into a 100- to 150-ml
centrifuge bottle, and centrifuge for 10 to 15 min, or until undissolved
material settles. Decant the supernatant extract through a Whatman
No. 4 filter paper, or equivalent, collecting the filtrate in a 100-ml
volumetric flask and retaining as much as possible of the undissolved
material in the centrifuge bottle. Add 10 ml of hot water to the original
beaker, washing off the watch glass with the water, and pour the
contents into the centrifuge bottle. Form a slurry, using a glass stirring
rod, and centrifuge. Decant through the same filter paper, and collect
the washings in the volumetric flask containing the initial extract.
Repeat the entire washing process two more times. Finally, wash the
filter paper with 10 to 15 ml of hot water. Cool the contents of the flask
to room temperature, dilute to volume with water, and mix.
Determine antimony, cadmium, and lead using an AAS/ICP-AES
technique appropriate to the specified level. Determine arsenic using the
ICP-AES/AAS-hydride technique. Alternatively, determine arsenic using
Method II of the Arsenic Limit Test, taking 3 g of the sample rather than
1 g. The selection of sample size and method of sample preparation
may be based on the principles of the methods described in Volume 4.
Aluminium oxide Reagents and sample solutions
0.01 N Zinc Sulfate
Dissolve 2.9 g of zinc sulfate (ZnSO4 ? 7H2O) in sufficient water to
make 1000 ml. Standardize the solution as follows: Dissolve 500 mg
of high-purity (99.9%) aluminium wire, accurately weighed, in 20 ml of
concentrated hydrochloric acid, heating gently to effect solution, then
transfer the solution into a 1000-ml volumetric flask, dilute to volume
with water, and mix. Transfer a 10 ml aliquot of this solution into a 500
ml Erlenmeyer flask containing 90 ml of water and 3 ml of
concentrated hydrochloric acid, add 1 drop of methyl orange TS and
25 ml of 0.02 M disodium ethylenediaminetetraacetate (EDTA) Add,
dropwise, ammonia solution (1 in 5) until the colour is just completely
changed from red to orange-yellow. Then, add:
(a): 10 ml of ammonium acetate buffer solution (77 g of
ammonium acetate plus 10 ml of glacial acetic acid, dilute to
1000 ml with water) and
(b): 10 ml of diammonium hydrogen phosphate solution (150 g
of diammonium hydrogen phosphate in 700 ml of water,
adjusted to pH 5.5 with a 1 in 2 solution of hydrochloric acid,
then dilute to 1000 ml with water).
Boil the solution for 5 min, cool it quickly to room temperature in a
stream of running water, add 3 drops of xylenol orange TS, and mix.
Using the zinc sulfate solution as titrant, titrate the solution to the first
yellow-brown or pink end-point colour that persists for 5-10 sec. (Note:
This titration should be performed quickly near the end-point by
adding rapidly 0.2 ml increments of the titrant until the first colour
change occurs; although the colour will fade in 5-10 sec, it is the true
end-point. Failure to observe the first colour change will result in an
incorrect titration. The fading end-point does not occur at the second
end-point.)
Add 2 g of sodium fluoride, boil the mixture for 2-5 min, and cool in a
stream of running water. Titrate this solution, using the zinc sulfate
solution as titrant, to the same fugitive yellow-brown or pink end-point
as described above.
Calculate the titre T of zinc sulfate solution by the formula:
T = 18.896 W / V
where
T is the mass (mg) of Al2O3 per ml of zinc sulfate solution
W is the mass (g) of aluminium wire
V is the ml of the zinc sulfate solution consumed in the
second titration
18.896 = (R × 1000 mg/g × 10 ml/2)/1000 ml and
R is the ratio of the formula weight of aluminium oxide to
that of elemental aluminium.
Sample Solution A
Accurately weigh 1 g of the sample and transfer to a 250-ml high-silica
glass Erlenmeyer flask. Add 10 g of sodium bisulfate (NaHSO4 ? H2O).
(Note: Do not use more sodium bisulfate than specified, as an excess
concentration of salt will interfere with the EDTA titration later on in the
procedure.) Begin heating the flask at low heat on a hot plate, and
then gradually raise the temperature until full heat is reached.
(Caution: perform this procedure in a well ventilated area. ) When
spattering has stopped and light fumes of SO3 appear, heat in the full
flame of a Meeker burner, with the flask tilted so that the fusion of the
sample and sodium bisulfate is concentrated at one end of the flask.
Swirl constantly until the melt is clear (except for silica content), but
guard against prolonged heating to avoid precipitation of titanium
dioxide. Cool, add 25 ml sulfuric acid solution (1 in 2), and heat until
the mass has dissolved and a clear solution results. Cool, and dilute to
120 ml with water. Introduce a magnetic stir bar into the flask.
Sample Solution B
Prepare 200 ml of an approximately 6.25 M solution of sodium
hydroxide. Add 65 ml of this solution to Sample Solution A, while
stirring with the magnetic stirrer; pour the remaining 135 ml of the
alkali solution into a 500-ml volumetric flask.
Slowly, with constant stirring, add the sample mixture to the alkali
solution in the 500-ml volumetric flask; dilute to volume with water,
and mix. (Note: If the procedure is delayed at this point for more than
2 hours, store the contents of the volumetric flask in a polyethylene
bottle.) Allow most of the precipitate to settle (or centrifuge for 5 min),
then filter the supernatant liquid through a very fine filter paper. Label
the filtrate Sample Solution B.
Sample Solution C
Transfer 100 ml of the Sample Solution B into a 500-ml Erlenmeyer
flask, add 1 drop of methyl orange TS, acidify with hydrochloric acid
solution (1 in 2), and then add about 3 ml in excess. Add 25 ml of 0.02
M disodium EDTA, and mix. [Note: If the approximate Al2O3 content is
known, calculate the optimum volume of EDTA solution to be added
by the formula: (4 x % Al2O3) + 5.]
Add, dropwise, ammonia solution (1 in 5) until the colour is just
completely changed from red to orange-yellow. Then add10 ml each
of Solutions 1 and 2 (see above) and boil for 5 min. Cool quickly to
room temperature in a stream of running water, add 3 drops of xylenol
orange TS, and mix. If the solution is purple, yellow-brown, or pink,
bring the pH to 5.3 - 5.7 by the addition of acetic acid. At the desired
pH, a pink colour indicates that not enough of the EDTA solution has
been added, in which case, discard the solution and repeat this
procedure with another 100 ml of Sample Solution B, using 50 ml,
rather than 25 ml, of 0.02 M disodium EDTA.
Procedure
Using the standardized zinc sulfate solution as titrant, titrate Sample
Solution C to the first yellow-brown or pink end-point that persists for
5-10 sec. (Important: See Note under “0.01 Zinc sulfate”.) This first
titration should require more than 8 ml of titrant, but for more accurate
work a titration of 10-15 ml is desirable.
Add 2 g of sodium fluoride to the titration flask, boil the mixture for 2-5
min, and cool in a stream of running water. Titrate this solution, using
the standardized zinc sulfate solution as titrant, to the same fugitive
yellow-brown or pink end-point as described above.
Calculation:
Calculate the percentage of aluminium oxide (Al2O3) in the sample
taken by the formula:
% Al2O3 = 100 × (0.005VT)/S
where
V is the number of ml of 0.01 N zinc sulfate consumed in
the second titration,
T is the titre of the zinc sulfate solution,
S is the mass (g) of the sample taken, and
0.005 = 500 ml / (1000mg/g × 100 ml).
Silicon dioxide Accurately weigh 1 g of the sample and transfer to a 250-ml high-silica
glass Erlenmeyer flask. Add 10 g of sodium bisulfate (NaHSO4 ? H2O).
Heat gently over a Meeker burner, while swirling the flask, until
decomposition and fusion are complete and the melt is clear, except
for the silica content, and then cool. (Caution: Do not overheat the
contents of the flask at the beginning, and heat cautiously during
fusion to avoid spattering.)
To the cooled melt add 25 ml of sulfuric acid solution (1 in 2) and heat
carefully and slowly until the melt is dissolved. Cool, and carefully add
150 ml of water by pouring very small portions down the sides of the
flask, with frequent swirling to avoid over-heating and spattering. Allow
the contents of the flask to cool, and filter through fine ashless filter
paper, using a 60 degree gravity funnel. Rinse out all the silica from
the flask onto the filter paper with sulfuric acid solution (1 in 10).
Transfer the filter paper and its contents into a platinum crucible, dry in
an oven at 1200, and heat the partly covered crucible over a Bunsen
burner. To prevent flaming of the filter paper, first heat the cover from
above, and then the crucible from below.
When the filter paper is consumed, transfer the crucible to a muffle
furnace and ignite at 1000o for 30 min. Cool in a desiccator, and
weigh. Add 2 drops of sulfuric acid (1 in 2) and 5 ml of concentrated
hydrofluoric acid (sp.gr. 1.15), and carefully evaporate to dryness, first
on a low-heat hot plate (to remove the HF) and then over a Bunsen
burner (to remove the H2SO4). Take precautions to avoid spattering,
especially after removal of the HF. Ignite at 1000o for 10 min, cool in a
desiccator, and weigh again. Record the difference between the two
weights as the content of SiO2 in the sample.
METHOD OF ASSAY
Accurately weigh about 150 mg of the sample, previously dried at 105o
for 3 hours, and transfer into a 500-ml conical flask. Add 5 ml of water
and shake until a homogeneous, milky suspension is obtained. Add 30
ml of sulfuric acid and 12 g of ammonium sulfate, and mix. Initially
heat gently, then heat strongly until a clear solution is obtained. Cool,
then cautiously dilute with 120 ml of water and 40 ml of hydrochloric
acid, and stir. Add 3 g of aluminium metal, and immediately insert a
rubber stopper fitted with a U-shaped glass tube while immersing the
other end of the U-tube into a saturated solution of sodium
bicarbonate contained in a 500-ml wide-mouth bottle, and generate
hydrogen. Allow to stand for a few minutes after the aluminium metal
has dissolved completely to produce a transparent purple solution.
Cool to below 50o in running water, and remove the rubber stopper
carrying the U-tube. Add 3 ml of a saturated potassium thiocyanate
solution as an indicator, and immediately titrate with 0.2 N ferric
ammonium sulfate until a faint brown colour that persists for 30
seconds is obtained. Perform a blank determination and make any
necessary correction. Each ml of 0.2 N ferric ammonium sulfate is
equivalent to 7.990 mg of TiO2.

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