Key Benefits:
THE DECREE OF THE PRESIDENCY OF THE GOVERNMENT NUMBER 2484/1967, OF 21 SEPTEMBER (
REAL DECREE 667/1983, OF 2 MARCH (
FOR ALL OF THE ABOVE, IT IS NECESSARY TO ESTABLISH OFFICIAL METHODS OF ANALYSIS THAT GUARANTEE THE QUANTIFICATION OF THE AFOREMENTIONED PARAMETERS.
IN ITS VIRTUE, ON THE PROPOSAL OF THE MINISTERS OF ECONOMY AND FINANCE; OF INDUSTRY AND ENERGY; OF AGRICULTURE, FISHERIES AND FOOD, AND OF HEALTH AND CONSUMPTION, PREVIOUS MANDATORY REPORT OF THE INTERMINISTERIAL COMMISSION FOR THE MANAGEMENT FOOD AND EARS REPRESENTATIVES OF THE SECTORS CONCERNED,
THIS MINISTRY OF RELATIONS WITH THE COURTS AND THE GOVERNMENT SECRETARIAT, HAS:
FIRST. THE METHODS OF ANALYSIS FOR FRUIT JUICES AND OTHER PLANTS AND THEIR DERIVATIVES REFERRED TO IN ANNEX I ARE APPROVED AS OFFICIAL
SECOND. WHERE THERE ARE NO OFFICIAL METHODS FOR CERTAIN ANALYSES AND UNTIL SUCH METHODS ARE PROPOSED BY THE COMPETENT AUTHORITY AND NOTIFIED IN ADVANCE BY THE INTER-MINISTERIAL COMMISSION FOR FOOD MANAGEMENT, THE APPROVED BY THE NATIONAL OR INTERNATIONAL BODIES OF RECOGNISED SOLVENCY.
REPEAL PROVISION
PROVISIONS OF EQUAL OR LOWER RANK THAT ARE OPPOSED TO THIS ORDER ARE REPEALED.
MADRID, 29 JANUARY 1988.
ZAPATERO GOMEZ
EXCMOS. SRES.
MINISTERS OF ECONOMY AND FINANCE, INDUSTRY AND ENERGY, AGRICULTURE, FISHERIES AND FOOD AND HEALTH AND CONSUMPTION.
ANNEX I
OFFICIAL METHODS OF ANALYSIS OF FRUIT JUICES AND OTHER VEGETABLES AND THEIR DERIVATIVES
INDEX
1.
PREPARATION OF THE SAMPLE.
2. DENSITY.
3. DRY EXTRACT.
4. PH.
5.
TOTAL ACIDITY.
6. ISOELECTRIC ACID.
7. BRIX GRADES.
8. SUGARS.
9.
RELATION SUGARS TOTAL/DEGREES BRIX.
10. ASCORBIC ACID.
11. TOTAL NITROGEN.
12. FORMOL INDEX.
13. ASHES.
14. PHOSPHORUS.
15. POTASSIUM.
16.
SORBIC ACID.
17. BENZOIC ACID.
18 (A). SULFUROUS ANHYDRIDE.
1.
PREPARING THE SAMPLE
1.1 PRINCIPLE. THE OPERATIONS DESCRIBED BELOW ARE INTENDED TO OBTAIN A SAMPLE FOR THE MOST HOMOGENEOUS ANALYSIS POSSIBLE. THEREFORE, ANY SIMPLIFICATION OR INSUFFICIENT TREATMENT IN THIS OPERATION MAY LEAD TO RESULTS THAT ARE NOT REPRESENTATIVE.
1.2 MATERIAL AND APARATOS:
1.2.1 ELECTRICAL SHREDDER OF MAXIMUM FINENESS DEGREE.
1.2.2 SCALES.
1.2.3 MAGNETIC STIRRER.
1.3 PROCEDURE:
1.3.1 JUICES AND NECTARS: HOMOGENIZE THE PRODUCT BEFORE EACH SAMPLING. CONTINUE AS THE METHODOLOGY OF EACH DETERMINATION INDICATES.
1.3.2 CREMOGENOS: TAKE ABOUT 400 GRAMS OF CREMOGENATE AND DILUTE UP TO ONE LITRE WITH DISTILLED WATER. MIX AND CONTINUE AS IN 1.3.1. THE RESULTS SHALL RELATE TO 100 GRAMS OF PRODUCT, TAKING INTO ACCOUNT THE DILUTION FACTOR.
1.3.3 PULPS: SHREDDING AND OBTAINING CREMOGENATE. CONTINUE AS IN 1.3.2. THE RESULTS SHALL RELATE TO 100 GRAMS OF THE PRODUCT, TAKING INTO ACCOUNT THE DILUTION FACTOR.
1.3.4 CONCENTRATED AND DEHYDRATED: TAKE AN ADEQUATE AMOUNT OF CONCENTRATE OR DEHYDRATE AND DILUTE TO ONE LITRE WITH DISTILLED WATER, SO THAT THE DISSOLUTION HAS APPROXIMATELY 10 BRIX. IN CASE OF PULPOUS TYPE CONCENTRATES (APRICOT, PEACH, PEAR, TOMATO, ETC) TO PERFORM THE DILUTION TO ABOUT 4 BRIX. CONTINUE WITH THE SPECIFIC METHODOLOGY OF EACH DETERMINATION. THE RESULTS SHALL RELATE TO 100 GRAMS OF PRODUCT, TAKING INTO ACCOUNT THE DILUTION TAKEN.
1.3.5 FROZEN: DEFROST THE SAMPLE AT ROOM TEMPERATURE AND CONTINUE AS APPROPRIATE.
1.3.6 GASIFIED JUICES: WHEN APPLICABLE, REMOVE CARBON DIOXIDE, BY AGITATION AT ROOM TEMPERATURE AND PARTIAL VACUUM.
2. DENSITY
2.1 PRINCIPLE. THE DENSITY (20 C/20 C) OF THE LIQUID TO BE ANALYZED IS DETERMINED BY MEANS OF THE PICNOMETER.
2.2 MATERIAL AND APARATOS:
2.2.1 STUDY.
2.2.2 DESECATOR.
2.2.3 YEAR TO 20 C.
2.2.4 ANALYTICAL BALANCE SENSITIVE TO 0.1 MILLIGRAMS.
2.2.5 50 MILLILITER OR SIMILAR REISCHAUER PICNOMETER.
THE REISCHAUER PICNOMETER CONSISTS OF A 50-MILLILITER FLASK OF CAPACITY, CLOSED WITH A GRINDING CAP FITTED WITH A NECK OF 6 CENTIMETERS IN LENGTH AND 4 MILLIMETERS OF INSIDE DIAMETER.
2.2.6 ERLENMEYER 500 MILLILITERS.
2.2.7 FUNNEL 10 CENTIMETERS IN DIAMETER.
2.2.8 CAPILLARY TUBES.
2.3 REAGENTS:
2.3.1 CHROMIC MIXTURE.
2.3.2 FILTER PAPER.
2.4 PROCEDURE. IF THE LIQUID TO BE ANALYZED CONTAINS AN APPRECIABLE AMOUNT OF CARBONIC GAS, COMPLETELY REMOVE THIS ONE BY STIRRING STRONGLY IN AN ERLENMEYER FOR AS LONG AS NECESSARY.
2.4.1 DETERMINATION OF THE WEIGHT OF THE EMPTY PICNOMETER:
CLEAN THE PICNOMETER WITH HOT CHROMIC MIXTURE AND RINSE CAREFULLY WITH DISTILLED WATER. DRY FOR THREE HOURS ON STOVE 105-108 C.
COOL IN THE DESICCATOR TO ROOM TEMPERATURE.
REGRET, WITH PRECISION OF FOUR DECIMAL PLACES.
2.4.2 DETERMINATION OF THE WEIGHT OF THE WATER-FILLED PICNOMETER:
FILL THE PICNOMETER TO THE MARK WITH DISTILLED WATER. TAPAR AND PUT IT IN A WATER BATH AT 20 C FOR 20 MINUTES.
BEING THE TEMPERATURE BALANCED, MAKE UP THE PICNOMETER (ALWAYS SUBMERGED IN THE WATER BATH) WITH THE HELP OF A CAPILLARY.
DRY THE EMPTY PART OF THE NECK OF THE PICNOMETER WITH FILTER PAPER.
PLACE THE STOPPER, REMOVE THE PICNOMETER FROM THE WATER BATH, AND DRY CAREFULLY.
WEIGH THE WATER-FILLED PICNOMETER WITH PRECISION OF FOUR DECIMAL PLACES.
2.4.3 DETERMINATION OF THE WEIGHT OF THE PICNOMETER FULL OF SAMPLE:
AFTER EMPTYING THE PICNOMETER, WASH SEVERAL TIMES WITH THE SAMPLE AND PROCEED AS IN 2.4.2 BY REPLACING THE WATER WITH THE SAMPLE.
2.5 CALCULATIONS. CALCULATE DENSITY 20 C/20 C, APPLYING THE FOLLOWING FORMULA:
D = C-A/B-A
SIENIT:
A = EMPTY PICNOMETER WEIGHT.
B = PICNOMETER WEIGHT FILLED WITH WATER UP TO THE ROOT.
C = PICNOMETER WEIGHT FULL OF SAMPLE TO ANALYZE UP TO THE ROOT.
THE DENSITY OBTAINED SHOULD BE EXPRESSED WITH A PRECISION OF FOUR DECIMAL PLACES.
2.6 REFERENCES. FÉDÉRATION INTERNATIONALE DES PRODUCTEURS DE JUS DE FRUITS. METHOD NUMBER 1, 1968.
3. DRY EXTRACT
(SOLUBLE SOLIDS)
3.1 PRINCIPLE. THE SOLUBLE SOLIDS CONTENT EXPRESSED IN G/L IS CALCULATED FROM THE VALUE OF THE DENSITY, OBTAINED ACCORDING TO THE OFFICIAL METHOD NUMBER 2 AND USING TABLE I.
TABLE I
TOTAL DRY EXTRACT (G/L)
(OMITTED BOX)
3.2 MATERIAL AND APARATOS. AS IN (2.2).
TABLE II
INTERPOLAR TABLE
(OMITTED BOX)
NUMBER 8 METHOD. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS.
YEAR 1985.
4. PH
4.1 PRINCIPLE.
POTENTIOMETRIC MEASUREMENT AT 20 C, AFTER REMOVAL OF CARBON DIOXIDE BY COLD AGITATION AND PARTIAL VACUUM.
4.2 MATERIAL AND APARATOS:
4.2.1 PH-METRO.
4.2.2 ELECTRO/S FOR PH MEASUREMENT.
4.3 REAGENTS:
4.3.1 SOLUTION BUFFER PH = 7; DISSOLVE 3,522 G OF POTASSIUM DIHYDROGEN PHOSPHATE (KH 2 PO 4); 14.020 G OF DISODIUM PHOSPHATE DISODIUM DODECAHYDRATE (NA 2 HPO 4 12H 2 O) AND LEAD TO A LITRE WITH DISTILLED WATER.
4.3.2 SOLUTION BUFFER PH = 4; DISSOLVE 10,211 G OF POTASSIUM ACID PHTHALATE (KHC 6 H 4 OR 4) (DRYING AN HOUR AT 105 C) IN A LITRE OF DISTILLED WATER AT 20 C.
4.4 PROCEDURE. TAKE A SAMPLE VOLUME FREE OF CARBON DIOXIDE AND DETERMINE THE PH.
4.5 EXPRESSION OF THE RESULTS. EXPRESS THE PH MEASURED AT 20 C WITH ONE OR TWO DECIMAL PLACES, ACCORDING TO THE ACCURACY OF THE APPARATUS.
4.6 REMARKS:
4.6.1 BEFORE EACH NEW MEASURE, CLEAN THE ELECTRODES WITH DISTILLED WATER AND DRY THEM WITH FILTER PAPER.
4.6.2 THE CALIBRATION IS DONE WITH THE HELP OF BUFFER SOLUTIONS FOLLOWING THE SPECIFIC INDICATIONS OF THE DEVICE.
4.6.3 FOR CALIBRATION, COMMERCIAL BUFFER SOLUTIONS CAN BE USED, BUT IN ANY CASE THE SOLUTION SHOULD BE RECENT. DO NOT USE A BUFFER CONTAINING MOULDS OR ANY KIND OF SEDIMENT.
4.7 REFERENCES. METHOD NUMBER 11. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1968.
5. TOTAL ACIDITY
5.1 PRINCIPLE. POTENTIOMETRIC ASSESSMENT WITH AN ALKALINE DISSOLUTION UP TO PH = 8.1 OF THE ACIDITY OF THE JUICE OR DERIVATIVE, AFTER ELIMINATION OF CARBON DIOXIDE.
5.2 MATERIAL AND APARATOS:
5.2.1 PHMETRO.
5.2.2 ELECTRO/S FOR PH MEASUREMENT.
5.2.3 MAGNETIC STIRRER.
5.2.4 GLASS MATERIAL FOR NORMAL USE IN THE LABORATORY.
5.3 REAGENTS:
5.3.1 0.1 N. SODIUM HYDROXIDE SOLUTION
5.4 PROCEDURE. TAKE A CARBON DIOXIDE-FREE SAMPLE VOLUME, PREPARED AS IN (1.3) IN A GLASS. RATE AGITATING WITH SODIUM HYDROXIDE (5.3.1) UP TO PH = 8.1.
5.5 CALCULATIONS. THE RESULTS ARE EXPRESSED IN GRAMS OF CITRIC/100 ML OF SAMPLE, TAKING INTO ACCOUNT THE DILUTION FACTOR:
G CTRICO/100 ML = (6.4). V1. F. N)/V2
SIENIT:
V1 = VOLUME OF SODIUM HYDROXIDE (NA0H) 0.1 N USED IN THE ASSESSMENT.
V 2 = SAMPLE VOLUME TAKEN.
F = SODIUM HYDROXIDE FACTOR.
5.6 REFERENCES. METHOD NUMBER 3. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1968.
6. ELECTRICAL ACID
6.1 PRINCIPLE. THE ACID IS SEPARATED FROM THE JUICES OR DERIVATIVES WITH BARIUM CHLORIDE AND IS DETERMINED BY ENZYMATIC.
IN THE PRESENCE OF THE ENZYME (ICDH) ENZYME DEHYDROGENASE (ICDH), THE ISOTARIC ACID (D-BITRATE) IS OXIDATIVELY DECARBOXYLATES TO KETOGGLUTARATE BY THE NICOTINAMIDA-ADENINE DUCLIDE PHOSPHATE (NADP).
(FORMULA OMITTED)
THE AMOUNT OF NADPH FORMED IN THIS REACTION IS STOICHIOMETRIC WITH THE AMOUNT OF THE AMOUNT OF ISUTREAT. THE INCREASE OF NADPH IS DETERMINED BY THE VARIATION OF THE ABSORBANCE AT 340 NM.
6.2 MATERIAL And APARATOS:
6.2.1 1-CM QUARTZ BUCKETS OF LIGHT PASSING.
6.2.2 SPECTROPHOTOMETER CAPABLE OF MEASURING 340 NM IN THE ULTRAVIOLET.
6.3 REAGENTS:
6.3.1 ACTIVATED CARBON.
6.3.2 SODIUM HYDROXIDE SOLUTION 4N.
6.3.3 4N HYDROCHLORIC ACID.
6.3.4 AMMONIA SOLUTION AT 25 PER 100 W/W, D = 0.91 G/ML.
6.3.5 ACETONE.
6.3.6 BARIUM CHLORIDE SOLUTION: DISSOLVE 30 G OF BARIUM CHLORIDE DIHYDRATE (BACL 2 H 2 O) IN DISTILLED WATER AND MAKE UP TO 100 ML.
6.3.7 SODIUM SULFATE SOLUTION: DISSOLVE 71 MG OF SODIUM SULPHATE (NA 2 SO 4 H 2 O) IN DISTILLED WATER AND MAKE UP TO 1 LITRE.
6.3.8 MANGANESE SULFATE SOLUTION: DISSOLVE 125 MG MANGANESE SULFATE (MN SO 4 H 2 O) IN 10 ML OF DISTILLED WATER. THE SOLUTION IS STABLE SIX MONTHS AT ROOM TEMPERATURE.
6.3.9 SOLUTION BUFFER PH = 7.0: DISSOLVE 2.42 G TRIS (HYDROXYMETHYL) AMINOMETHANE AND 35 MG EDTA-NA 2 2H 2 OR IN 80 ML DISTILLED WATER, ACIDIFY HPH = 7, WITH HYDROCHLORIC ACID (6.3.3) AND MAKE UP TO 100 ML WITH WATER. THIS SOLUTION IS STABLE FOR AT LEAST ONE YEAR AT + 4 C.
6.3.10 SOLUTION BUFFER PH = 7.4: DISSOLVE 2.42 G TRIS (HYDROXYMETHYL) AMINOMETHANE AND 35 MG ETDA-NA 2 2H 2 OR WITH 80 ML DISTILLED WATER. ACIDIFY UP TO PH = 7.4 WITH HYDROCHLORIC ACID (6.3.3) AND MAKE UP TO 100 ML. THIS SOLUTION IS STABLE FOR AT LEAST ONE YEAR AT + 4 C.
6.3.11 NADP SOLUTION: DISSOLVE 50 MILLIGRAMS B NICOTINAMIDE-ADENINE-DBETIDE DISODIUM PHOSPHATE (B NADP-NA 2) IN 5 MILLILITRES OF BIDESTIZED WATER. THIS SOLUTION IS STABLE FOR AT LEAST FOUR WEEKS AT + 4 C.
6.3.12 ENZYME SOLUTION (ICDH): DISSOLVE 10 MG OF LYOPHILISATE IN 1 ML OF GLYCERIN SOLUTION (50 PER 100 V/V WITH DISTILLED WATER). THIS SOLUTION IS STABLE FOR FOUR WEEKS AT + 4 C.
6.4 PROCEDURE:
6.4.1 SAMPLE PREPARATION:
TREAT 10 ML OF SAMPLE WITH 5 ML OF SODIUM HYDROXIDE (6.3.2) IN A 100 ML CENTRIFUGE TUBE AND LEAVE TO REST FOR 10 MINUTES AT ROOM TEMPERATURE (20C).
ADD 5 ML OF HYDROCHLORIC ACID (6.3.3) AND DILUTE THE SOLUTION UP TO 25 ML. ADD 2 ML OF AMMONIA SOLUTION (6.3.4), 3 ML OF BARIUM CHLORIDE (6.3.6) AND 20 ML OF ACETONE (6.3.5). MIX PERFECTLY WITH A GLASS ROD. CENTRIFUGE 5 MINUTES AT 3,000 REVOLUTIONS PER MINUTE. DECANT THE SUPERNATANT WITH CARE AND ADD 20 ML OF SODIUM SULFATE SOLUTION (6.3.7) TO THE PRECIPITATE IN THE CENTRIFUGE TUBE AND SHAKE WITH GLASS ROD. DISSOLVE THE WATER BATH PRECIPITATE BY STIRRING FREQUENTLY FOR 10 MINUTES; COOL AND QUANTITATIVELY TRANSFER TO A 50 ML VOLUMETRIC FLASK BY SCRAPING WITH A BUFFER SOLUTION PH = 7 (6.3.9). TRANSFER THE CONTENTS OF THE FLASK TO ANOTHER CONTAINING 1 G OF ACTIVATED CARBON (6.3.1), LEAVE TO REST 5 MINUTES AND FILTER. THE CLEAR, COLOURLESS AND CLEAR FILTERED LIQUID IS USED FOR THE DETERMINATION OF THE ACID IN THE SAMPLE.
6.4.2 DETERMINATION:
THE DETERMINATION IS MADE AT AN APPROXIMATE TEMPERATURE OF 20 C. THE MAXIMUM ABSORPTION OF NADPH IS 340 NM.
PUT IN BUCKETS/WHITE (ML)/SAMPLE (ML) BUFFER PH = 7.4 (6.3.10) 3.00 2.00
MANGANESE SULFATE (6.3.8) 0.10 0.10
NADP SOLUTION (6.3.11) 0.10 0.10
SAMPLE 1.00
MIX, WAIT FOR 3 MINUTES, AND READ THE ABSORBANCES (AT 1, BOTH WHITE AND SAMPLE IN FRONT OF AIR.
BEGIN THE REACTION BY ADDING:
ICDH ENZYME SOLUTION (6.3.12) 0.01 0.01
MIX AND WAIT FOR THE REACTION TO STOP (4-10 MINUTES); READ THE ABSORBANCES (A 2). CONTINUE READING THE ABSORBANCES AT INTERVALS OF 2 MINUTES UNTIL THE ABSORBANCE READING IS CONSTANTLY INCREASED. TAKE HOW (A 2) THE FIRST ABSORBANCE VALUE FROM WHICH CONSTANT INCREASES HAVE BEEN OBSERVED.
6.5 CALCULATIONS:
(FORMULA OMITTED)
THE CALCULATION OF THE CONCENTRATION OF ACID-ELECTRIC ACID ACCORDING TO E FOLLOWS THE LAW OF LAMBERT-BEER. THEREFORE THE CONTENT IN MG/L OF THE ISOELECTRIC ACID SHALL BE GIVEN BY THE EXPRESSION:
(FORMULA OMITTED)
6.6 REFERENCES: METHOD NUMBER 54 FEDERATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1984.
7. GRADO BRIX
7.1 PRINCIPLE. MEASURE OF REFRACTIVE INDEX AND CONVERSION TO DEGREES BRIX BY ATTACHED TABLES.
7.2 MATERIAL AND APARATOS:
7.2.1 REFRACTOMETER PROVIDED WITH EQUIPMENT REQUIRED TO MAINTAIN TEMPERATURE AT 20 C.
7.2.2 FLASKS OR GLASS CONTAINERS THAT CLOSE HERMETICALLY.
7.3 PROCEDURE:
PLACE THE REFRACTOMETER IN AN ILLUMINATED PLACE WITH DIFFUSE LIGHT.
CIRCULAR WATER AT CONSTANT TEMPERATURE PREFERABLY AT 20 C THROUGH THE PRISMS OF THE REFRACTOMETER.
CALIBRATE THE REFRACTOMETER WITH H 2 OR DISTILLED AT 20 C, WHOSE THEORETICAL REFRACTIVE INDEX AT THAT TEMPERATURE IS 1.3330.
PLACE THE SAMPLE IN A TIGHTLY CLOSED CONTAINER IN A BATHROOM AT 20 C AND WAIT FOR IT TO REACH THAT TEMPERATURE. MEASURE THE REFRACTIVE INDEX.
7.4 CALCULATIONS. FROM THE VALUE OBTAINED FROM THE REFRACTIVE INDEX THE GRADES BRIX ARE DETERMINED BY TABLE I.
EXPRESS THE RESULTS WITH A DECIMAL NUMBER.
7.5 REMARKS. IF ANOTHER TEMPERATURE IS USED TO MEASURE THE REFRACTIVE INDEX, CORRECT GRADES BRIX USING TABLE II.
7.6 REFERENCES:
7.6.1 METHOD NUMBER 8. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1962.
7.6.2 METHODS ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS. REFERENCE TABLES. YEAR 1984.
TABLE I
(OMITTED BOX)
TABLE II
(OMITTED BOX)
8. SUGARS
8.1 PRINCIPLE. PRIOR ELIMINATION OF ALL REDUCING SUBSTANCES OTHER THAN SUGARS, DUE TO DEFECATION AND SUBSEQUENT ASSESSMENT BASED ON THE REDUCTION OF SUGARS ON A CUPRO-ALKALINE SOLUTION. FOR THE DETERMINATION OF NON-REDUCING SUGARS IT IS NECESSARY TO PROCEED TO A PRIOR HYDROLYSIS.
8.2 MATERIAL AND APARATOS.
8.2.1 REQUIRED MATERIAL FOR VOLUMETRIES.
8.2.2 WATER YEAR.
8.2.3 ERLENMEYER 300 ML WITH REFLUX COOLANT.
8.3 REAGENTS.
8.3.1 SULFURIC ACID SOLUTION OF 25 PER 100 (6 N).
8.3.2 HYDROCHLORIC ACID SOLUTION OF 32 PER 100, D = 1,16 G/ML.
8.3.3 POTASSIUM HYDROXIDE SOLUTION OF 30 PER 100.
8.3.4 POTASSIUM HYDROXIDE SOLUTION OF 0.5 PER 100.
8.3.5 POTASSIUM IODIDE SOLUTION: DISSOLVE 30 G OF KI IN 100 ML OF DISTILLED WATER.
8.3.6 STARCH SOLUTION: DISSOLVE 1 G OF STARCH IN 100 ML OF DISTILLED WATER.
8.3.7 CARREZ I SOLUTION: DISSOLVE 150 G OF POTASSIUM HEXACIANOFERDE (II) TRIHYDRATE [K 4 FE (CN) 6. 3H 2 O] IN A WATER LITRO.
8.3.8 SOLUTION CARREZ II: DISSOLVE 300 G OF ZINC SULFATE HEPTAHYDRATE (ZN SO 4. 7H 2 O) IN A WATER LITRO.
8.3.9 LUFF-SCHOORL SOLUTION: DISSOLVE 50 G OF CITRIC ACID C 6 H 8 OR 7 H 2 OR IN 500 ML OF WATER AND 143.7 G OF ANHYDROUS SODIUM CARBONATE IN 350 ML OF WARM WATER, WHEN COOLED, CAREFULLY MIX BOTH SOLUTIONS.
DISSOLVE 25 G OF BORE (II) SULPHATE PENTAHYDRATE (CU SO 4. 5H 2 O) IN 100 ML OF WATER. ADD TO THE PREVIOUS SOLUTION AND MAKE UP TO ONE LITRE WITH WATER.
8.3.10 SODIUM THIOSULFATE SOLUTION (NA 2 S 2 O 3. 5H 2 O) 0,1 N (24.8 G/1).
8.3.11 PHENOLPHTHALEIN SOLUTION: DISSOLVE 0.1 G OF PHENOLPHTHALEIN IN 100 ML OF ETHANOL.
8.4 PROCEDURE.
8.4.1 SAMPLE PREPARATION: TAKE A CONVENIENT AMOUNT OF SAMPLE (2-5 ML). DILUTE WITH WATER. ADD 5 ML OF THE CARREZ I SOLUTION (8.3.7) AND 5 ML OF THE ROAD SOLUTION II (8.3.8). MIX AND MAKE UP TO 250 ML WITH WATER. LEAVE TO REST AND FILTER.
8.4.2 DETERMINATION OF SUGARS BEFORE INVESTMENT.
REDUCING SUGARS: TAKE 25 ML OF THE FILTERED SAMPLE (WHICH DOES NOT CONTAIN MORE THAN 50 MG OF SUGARS) IN A FLASK WITH 25 ML OF LUFF-SCHOORL SOLUTION (8.3.9). ADD A FEW GLASS BEADS AND CONNECT THE REFLUX COOLANT. HEAT THE FLASK WITH A POWERFUL FLAME UNTIL IT REACHES THE BOIL IN TWO MINUTES AND KEEP IT FOR TEN MINUTES EXACTLY. COOL WITH WATER AND WHEN THE FLASK IS COLD, ADD WITH CARE 10 ML OF POTASSIUM IODIDE (8.3.5), 25 ML OF SULPHURIC ACID (8.3.1) AND 2 ML OF STARCH SOLUTION (8.3.6). TITRATE WITH SODIUM THIOSULFATE (8.3.10) UNTIL THE INDICATOR TURNS. IF LESS THAN 5 ML OF THE ASSESSMENT HAD BEEN USED, REPEAT THE DETERMINATION USING A DILUTION OF THE MOST APPROPRIATE SAMPLE.
PERFORM A BLANK TEST IN PARALLEL USING 25 ML OF DISTILLED WATER:
D 1 NUMBER OF MILLILITRES OF SODIUM THIOSULFATE 0.1N EMPLOYED IN THE TARGET ASSESSMENT.
D 2 NUMBER OF MILLILITRES OF SODIUM THIOSULFATE 0.1N USED IN THE SAMPLE ASSESSMENT.
8.4.3 DETERMINATION OF THE SUGARS AFTER THE INVESTMENT:
TOTAL SUGARS: IN A 100 ML FLASK MIX 50 ML OF FILTRATE OBTAINED IN (8.4.1) WITH 5 ML OF HYDROCHLORIC ACID (8.3.2) AND BRING THE FLASK TO THE WATER BATH AT 70 C, WHERE THE SAMPLE WILL ACQUIRE 67 C IN TWO OR THREE MINUTES. KEEP THE SAMPLE BETWEEN 67-70 C, FIVE MINUTES. COOL TO ABOUT 20 C AND NEUTRALIZE WITH POTASSIUM HYDROXIDE (8.3.3) AND (8.3.4) USING PHENOLPHTHALEIN (8.3.11) AS AN INDICATOR.
ENRASAR 100 ML WITH WATER AND CONTINUE AS IN (8.4.2). PERFORM A BLANK TEST IN PARALLEL.
D 3 NUMBER OF MILLILITRES OF SODIUM THIOSULFATE 0.1N EMPLOYED IN THE TARGET ASSESSMENT.
D 4 NUMBER OF MILLILITRES OF SODIUM THIOSULFATE 0.1N USED IN THE SAMPLE ASSESSMENT.
8.5 CALCULATIONS. WITH THE VALUES D 5 AND D 6 AND TABLE I THE CONTENTS IN MG OF GLUCOSE (A) AND (B) (INTERPOLAR IF NECESSARY):
D 5 = D 1-D 2; FROM TABLE I YOU GET THE VALUE (A).
D 6 = D 3-D 4; FROM TABLE I YOU GET THE VALUE (B).
REDUCING SUGARS IN G GLYCOS/100 ML = A/V
TOTAL SUGARS IN G GLYCOS/100 ML = 2 (B/V)
SIENIT:
V = SAMPLE VOLUME
8.6 REMARKS. DETERMINE THE SODIUM THIOSULFATE FACTOR (8.3.10) AND TAKE IT INTO ACCOUNT WHEN CALCULATING D 1, D 2, D 3, D 4
8.7 REFERENCES. METHOD NUMBER 4. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1985.
TABLE I
FOR 25 ML LUFF-SCHOORL REAGENT
(OMITTED BOX)
9. RELATIONSHIP SUGARS TOTAL/DEGREES BRIX
9.1 PRINCIPLE. ESTIMATION OF THE TOTAL SUGAR CONTENT OF THE JUICE OR DERIVATIVE AGAINST ITS BRIX GRADES.
9.2 MATERIAL AND APARATOS:
9.2.1 AS IN 7.2 AND 8.2.
9.3 PROCEDURE. DIVIDE THE CONTENTS OF THE TOTAL SUGARS OBTAINED IN 8.5 AMONG THE GRADES BRIX OBTAINED IN 7.4.
9.4 EXPRESSION OF RESULTS. EXPRESS THE RESULTS WITH TWO DECIMAL PLACES.
10. ASCORBIC ACID
10.1 PRINCIPLE. SEPARATION, IDENTIFICATION AND QUANTIFICATION OF ASCORBIC ACID BY HIGH EFFICACY LIQUID CHROMATOGRAPHY BY DETECTING IT IN ULTRAVIOLET AT 268 NM.
10.2 MATERIAL And APARATOS:
10.2.1 SAMPLE FILTRATION EQUIPMENT AND SOLVENT TO REMOVE PARTICLES ABOVE 0.5 MM.
10.2.2 LIQUID CHROMATOGRAPH EQUIPPED WITH VARIABLE WAVELENGTH ULTRAVIOLET DETECTOR AND LOGGER.
10.2.3 NH 2 COLUMN 2 LICHORSORB 250 X 4.6 MILLIMETERS OF 10 MICRASM OR SIMILAR.
10.3 REAGENTS:
10.3.1 STANDARD SOLUTION OF ASCORBIC ACID IN DISTILLED WATER OF 300 MILLIGRAM/LITRE PREPARED IN THE DAY AND PRESERVED IN MATRAZ COLOUR TOPAZ.
10.3.2 SOLUTION TO:
BUFFER PHOSPHATE, PH 3.5. DISSOLUTION 0.005 M OF POTASSIUM DIHYDROGEN PHOSPHATE (KH 2 PO 4):
FILTER THIS SOLUTION WITH 10.2.1.
10.3.3 SOLUTION B:
ACETONITRILE FOR HPLC.
10.4 PROCEDURE:
10.4.1 GUIDANCE CHROMATOGRAPHIC CONDITIONS:
MOBILE PHASE:
PHOSPHATE/ACETONITRILE BUFFER: 60: 40 (V/V).
FLOW: 1 MILLIITRO/MINUTE.
10.4.2 CALIBRATION: INJECT 10 TO 20 ML OF THE STANDARD SOLUTION 10.3.1 INTO THE CHROMATOGRAPH AND CALCULATE THE RESPONSE FACTOR:
C O
RESPONSE FACTOR (F) =
A P
SIENIT:
C O = CONCENTRATION IN MILLIGRAM/LITRE OF ASCORBIC ACID.
A P = PEAK AREA IN THE PATTERN SOLUTION CHROMATOGRAM.
10.4.3 DETERMINATION: HOMOGENIZE. FILTER WITH 10.2.1 AND INJECT 10 TO 20 ML IN THE CHROMATOGRAPH.
10.5 CALCULATIONS. THE ASCORBIC ACID CONTENT EXPRESSED IN MILLIGRAM/LITRE (WITHOUT DECIMALS) SHALL BE OBTAINED BY THE FOLLOWING FORMULA:
ASCORBICO ACID (MILIGRAMO/LITRO) = F X AC
SIENIT:
F = RESPONSE FACTOR.
AC = PEAK AREA A. ASCORBIC AREA IN THE SAMPLE.
10.6 REMARKS:
10.6.1 THE DETERMINATION OF ASCORBIC ACID SHALL BE PERFORMED IMMEDIATELY AFTER THE OPENING OF THE CONTAINER.
10.6.2 WITH THIS METHOD IS NOT DETERMINED DEHYDROASCORBIC ACID.
10.6.3 IN SOME CASES, PRIOR CENTRIFUGATION OF THE SAMPLE IS NECESSARY.
11. TOTAL NITROGEN
11.1 PRINCIPLE. DIGESTION OF THE PRODUCT WITH CONCENTRATED SULPHURIC ACID, IN THE PRESENCE OF A CATALYST, IN WHICH THE ORGANIC NITROGEN IN AMMONIUM IONS IS TRANSFORMED WHICH, IN A STRONGLY BASIC MEDIUM, IS DISPLACED IN THE FORM OF AMMONIA AND COLLECTED ON BORIC ACID. THE SUBSEQUENT EVALUATION WITH HYDROCHLORIC ACID ALLOWS THE CALCULATION OF THE INITIALLY PRESENT AMOUNT OF ORGANIC NITROGEN AND AMMONIACAL IN THE SAMPLE.
11.2 MATERIAL And APARATOS:
11.2.1 KJELDAHL OR LIKE APPARATUS.
11.3 REAGENTS:
11.3.1 CONCENTRATED SULPHURIC ACID 96 PER 100 D = 1.84 GRAMS/MILLILITRES.
11.3.2 CATALYTIC MIXING: 100 GRAMOS H 2 SO 4; 10 GRAMOS CU 2 SO 4. 5H 2 O AND 1 GRAM OF SELENIUM POWDER.
11.3.3 SODIUM HYDROXIDE SOLUTION AT 40 PER 100 P/V.
11.3.4 BORIC ACID SOLUTION AT 4 PER 100 P/V.
11.3.5 HYDROCHLORIC ACID SOLUTION 0.05 N.
11.3.6 INDICATOR: WEIGH 105 MILLIGRAMS OF METHYL RED AND 150 MILLIGRAMS OF BROMORESOL GREEN AND DISSOLVE 100 MILLILITRES WITH ETHANOL.
11.4 PROCEDURE:
PUT IN A KJELDHAL FLASK A SUITABLE QUANTITY OF SAMPLE (5-10 MILLILITRES) AND SUCCESSIVELY INTRODUCE 20 MILLILITRES OF H 2 SO 4 CONCENTRATE (11.3.1) AND 6 GRAMS OF CATALYST (11.3.2). GENTLY MIX BY ROTATION AND PLACE THE FLASK IN A HEATING BATTERY BY PUTTING A SUITABLE FUNNEL IN THE MOUTH. HEAT GENTLY AT THE BEGINNING AND WHEN THE SET BEGINS TO DISCOLOR, INCREASE THE INTENSITY OF THE HEATING. KEEP IT UNTIL FULL DISCOLORATION, PROLONGING IT FOR A FEW MINUTES.
ALLOW TO COOL DOWN TO ROOM TEMPERATURE AND ADD WATER, DISSOLVING BY SMOOTH ROTATION THE CRYSTALLIZED POTASSIUM SULFATE.
IN A 100 MILLILITER ERLENMEYER, PUT 10 MILLILITRES OF BORIC ACID AT 4 PER 100 (11.3.4) AND A FEW DROPS OF INDICATOR (11.3.6). TO THE BOTTOM IN THE ERLENMEYER THE ELONGATION OF THE DISTILLATION APPARATUS.
ADD ABOUT 30 MILLILITRES OF NAOH 40 PER 100 (11.3.3) AND DISTILLED WATER IN THE DISTILLATION FLASK. HEAT BOILING BOILING AND COLLECT THE DISTILLATE UNTIL FULL DRAG OF THE AMMONIA FROM THE SAMPLE.
REMOVE THE ERLENMEYER, WASH THE ELONGATION AND THE INTERIOR OF THE REFRIGERANT BY COLLECTING THE WASHING WATER OVER THE DISTILLATE. RATE HC1 0.05 N (11.3.5) TO TURN THE INDICATOR. SIMULTANEOUSLY PERFORM A BLANK TEST.
11.5 CALCULATION. THE RESULT WILL BE EXPRESSED IN MILLIGRAMS OF NITROGENO/100 MILLIGRAMS.
MILLIGRAMS OF NITROGEN/100 MILLIGRAMS = (1401. (V1-V2) N. F)/V
SIENIT:
v1 = VOLUME, IN MILLILITRES, OF HCI SPENT ON VALUATION.
V2 = VOLUME, IN MILLILITRES, OF HCI SPENT IN THE BLANK TEST.
F = HC1 FACTOR.
N = HC1 NORMALITY.
V = VOLUME OF THE SAMPLE, IN MILLILITRES.
11.6 REFERENCES:
11.6.1 NORMA ISO. R 937.
11.6.2 METHOD NUMBER 28. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1965.
12. FORMAL INDEX
12.1 PRINCIPLE. ASSESSMENT OF THE ACIDITY OF THE COMPOUNDS FORMED BY THE REACTION OF FORMALDEHYDE WITH THE AMINO ACIDS.
12.2 MATERIAL And APARATOS:
12.2.1 PH-METRO.
12.2.2 ELECTROD/S FROM PH.
12.2.3 NORMAL LABORATORY USE MATERIAL.
12.3 REAGENTS:
12.3.1 0.1 N. SODIUM HYDROXIDE SOLUTION
12.3.2 OXYGENATED WATER AT 30 PER 100.
12.3.3 FORMALDEHYDE SOLUTION. BRING THE FORMALDEHYDE, 35 PER 100, AT LEAST TO PH 8.1, BY SOLUTION OF SODIUM HYDROXIDE (12.3.1), USING THE PH-METER.
CHECK HOURLY.
12.4 PROCEDURE. PUT 25 MILLILITRES OF SAMPLE IN A GLASS, NEUTRALISE WITH SODIUM HYDROXIDE (12.3.1) HSTA PH 8.1, USING THE PH-METER. ADD 10 MILLILITRES OF THE FORMALDEHYDE SOLUTION (12.3.3) AND MIX. AFTER ONE MINUTE, PERFORM THE POTENTIOMETRIC ASSESSMENT OF THE SOLUTION PROBLEM WITH THE SODIUM HYDROXIDE SOLUTION (12.3.1) UP TO PH 8.1.
IF MORE THAN 20 MILLILITRES OF THE SODIUM HYDROXIDE SOLUTION HAD BEEN USED, THE ASSESSMENT SHOULD BE CARRIED OUT AGAIN USING 15 MILLILITRES OF FORMALDEHYDE SOLUTION INSTEAD OF 10 MILLILITRES.
IF THE SAMPLE CONTAINS SULFUR DIOXIDE, ADD A FEW DROPS OF OXYGENATED WATER (12.3.2) BEFORE NEUTRALIZATION.
12.5 CALCULATIONS. THE FORMOL INDEX OF THE SAMPLE ANALYSED IS EQUAL TO THE AMOUNT OF ALKALINE SOLUTION USED IN THE ASSESSMENT, EXPRESSED IN MILLILITRES OF 0,1 N SODIUM HYDROXIDE (WITH A DECIMAL FIGURE) AND CORRESPONDING TO 100 MILLILITRES OF SAMPLE:
I. F. = (V.F. 100/V ')
SIENIT:
V = VOLUME OF SODIUM HYDROXIDE 0,1 N USING IN THE DETERMINATION.
F = SODIUM HYDROXIDE FACTOR USED.
V' = SAMPLE VOLUME USED IN THE DETERMINATION.
12.6 REMARKS. IN LEMON JUICE DILUTE 1/1 WITH H 2 OR DISTILLED BEFORE THE TITRATION.
12.7 REFERENCES. METHOD NUMBER 30. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1984.
13. ASHES
13.1 PRINCIPLE. THEY ARE CALLED ASHES OF A JUICE OR DERIVATIVE, TO THE WHOLE OF THE WASTE INCINERATION PRODUCTS OBTAINED AFTER THE EVAPORATION OF THE SAMPLE, SO THAT ALL CATIONS (EXCEPT AMMONIUM) IN THE FORM OF CARBONATES AND OTHER SALTS CAN BE OBTAINED ANHYDROUS MINERALS.
13.2 MATERIAL And APARATOS:
13.2.1 PLATINUM, QUARTZ OR SIMILAR CAPSULE OF ABOUT 80 MILLIMETERS IN DIAMETER, WITH FLAT BOTTOM.
13.2.2 WATER BATH AND SAND BATH.
13.2.3 FURNACE OR ELECTRIC MUFFLE.
13.2.4 ANALYTICAL SCALES WITH SENSITIVITY OF 0.1 MILLIGRAM.
13.3 PROCEDURE. PUT AN APPROPRIATE VOLUME OF SAMPLE (25 MILLILITRES) WELL HOMOGENISED IN A TARADA CAPSULE. EVAPORATE WITH CAUTION IN THE WATER BATH. ADD TO THE DRY RESIDUE SOME DROPS OF OLIVE OIL, HEAT SLOWLY IN THE SAND BATH UNTIL MOST OF THE ORGANIC SUBSTANCE IS CHARRED. ENTER THE CAPSULE IN THE OVEN OR MUFFLE AT 525 C (APPROXIMATELY SIX TO EIGHT HOURS).
IF THE CARBONIZATION IS NOT COMPLETE, MOISTEN THE ASHES WITH DISTILLED WATER, EVAPORATE AGAIN AND CALCINED. REPEAT THIS OPERATION AS MANY TIMES AS NECESSARY UNTIL WHITE ASHES ARE OBTAINED.
COOL THE CAPSULE IN A DESICCATOR (ABOUT THIRTY MINUTES) AND WEIGH.
13.4 CALCULATIONS. THE ASH CONTENT EXPRESSED IN GRAMS/100 MILLILITRES SHALL BE GIVEN BY THE FOLLOWING FORMULA:
ASHES (G/100 ML SAMPLE) = (P2-P1) 100/V
SIENIT:
P1 = WEIGHT IN GRAMS OF THE CAPSULE EMPTY. (G/100 ML P2 = WEIGHT IN GRAMS OF THE ASHES PLUS THE CAPSULE.
V = VOLUME OF THE SAMPLE ENMILLILITRES.
13.5 REMARKS. IN SOME CASE THE ASHES CAN PRESENT A SLIGHT COLORATION, WHICH IS ACCEPTED AND DOES NOT REQUIRE FURTHER TREATMENT.
13.6 REFERENCES. METHOD NUMBER 9. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS.
YEAR 1962.
14. PHOSPHORUS
14.1 PRINCIPLE.
TRANSFORMATION OF THE PHOSPHORATED COMPOUNDS INTO ORTHOPHOSPHATES AND SUBSEQUENT SPECTROPHOTOMETRIC ASSESSMENT AS PHOSPHOMOLIBDOVANADATE.
14.2 MATERIAL AND APARATOS:
14.2.1 SPECTROPHOTOMETER OR COLORIMETER CAPABLE OF PERFORMING READINGS AT 400 NM.
14.2.2 PARTY OF ARENA.
14.3 REAGENTS:
14.3.1 HYDROCHLORIC ACID 36% D = 1,18 G/ML.
14.3.2 NITRIC ACID 70% D = 1.42 G/ML.
14.3.3 AMMONIUM MOLYBDATE SOLUTION: DISSOLVE 20 GRAMS OF AMMONIUM MOLYBDATE TETRAHYDRATE (NH 4) 6 MO 7 OR 24 .4H 2 OR IN 200 MILLILITRES OF HOT WATER.
14.3.4 AMMONIUM METAVANADATE SOLUTION: DISSOLVE 1 GRAM OF AMMONIUM METAVANADATE (NH 4) VO 3 IN 300 MILLILITRES OF HOT DISTILLED WATER, COOL AND ADD 140 MILLILITRES OF NITRI CO (14.3.2).
14.3.5 METAMOLIBDOVANADATO SOLUTION: SLOWLY POUR AND AGITATE THE AMMONIUM MOLYBDATE SOLUTION (14.3.3) ON THE AMMONIUM METAVANADATE SOLUTION (14.3.4) AND MAKE UP TO 1 LITER OF DISTILLED WATER.
14.3.6 CONCENTRATED SULPHURIC ACID 96% D = 1.84 G/ML.
14.3.7 PHOSPHATE PATTERN SOLUTION: DISSOLVE 4,3885 GRAMS OF POTASSIUM DIHYDROGEN PHOSPHATE KH 2 PO 4 (PREVIOUSLY DRIED TWO HOURS AT 105 C) IN DISTILLED WATER, ADD 2 MILLILITRES OF SULPHURIC ACID (14.3.6) AND DILUTE TO 1 LITRE (1 MILLILITRE CONTAINS 1 MILLIGRAM OF P.
14.4 PROCEDURE:
14.4.1 PREPARATION OF THE SAMPLE:
DISSOLVE THE ASHES OBTAINED IN METHOD NUMBER 13 IN 5 MILLILITRES OF HCL (14.3.1) AND 2 MILLILITRES OF HNO 3 (14.3.2). SIMMER GENTLY FOR FIFTEEN MINUTES IN A SAND BATH. LEAD TO A 50 MILLILITRE FLASK AND MAKE UP WITH DISTILLED WATER.
PERFORM A BLANK TEST IN PARALLEL.
14.4.2 COLOUR DEVELOPMENT: TAKE 5 MILLILITRES OF THE SOLUTIONS OBTAINED IN (14.4.1) IN A 50 MILLILITRE GRADUATED FLASK. CARRY UP TO 10 MILLILITRES WITH DISTILLED WATER. ADD 10 MILLILITRES OF THE REAGENT (14.3.5) AND MAKE UP TO 50 MILLILITRES WITH DISTILLED WATER. AFTER THIRTY MINUTES, READ THE ABSORBANCES AT 400 NM.
14.4.3 PATTERN CURVE: DILUTE 10 MILLILITRES OF THE STANDARD SOLUTION (14.3.7) IN 250 MILLILITRES OF DISTILLED WATER. (1 MILLILITRE OF THIS SOLUTION CONTAINS 40 MG OF P). TAKE 0, 2, 3, 4, 5 AND 10 MILLILITRES OF THE SOLUTION OF 40 MG/MILLILITRE (WITH A CONTENT OF 0, 80, 120, 160, 200 AND 400 MG). CONTINUE AS IN (14.4.2) AND DRAW THE CALIBRATION CURVE.
14.5 CALCULATIONS. THE TOTAL P CONTENT EXPRESSED IN MILLIGRAMS OF W/100 MILLILITRES OF SAMPLE IS OBTAINED BY COMPARING THE ABSORBANCES OF THE SAMPLE WITH THE PATTERN CURVE, TAKING INTO ACCOUNT THE TARGET AND THE DILUTION FACTOR.
A = MG OF P/100 ML = A/V
SIENIT:
A = MG OF P READ IN THE PATTERN CURVE.
V = VOLUME OF THE SAMPLE IN MILLILITRES.
14.6 REFERENCES. METHOD NUMBER 50.
FEDERATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1983.
15. POTASSIUM
15.1 PRINCIPLE. POTASSIUM IS DETERMINED BY ATOMIC ABSORPTION SPECTROPHOTOMETRY OR FLAME PHOTOMETRY, AFTER ADDITION OF LITHIUM CHLORIDE, TO PREVENT PARTIAL IONIZATION OF THE METALS IN THE FLAME.
15.2 MATERIAL AND APARATOS:
15.2.1 ATOMIC ABSORPTION SPECTROPHOTOMETER OR FLAME PHOTOMETER.
15.2.2 NORMAL LABORATORY USE MATERIAL.
15.3 REAGENTS:
15.3.1 POTASSIUM SOLUTION OF 1,000 MILLIGRAM/LITRE: DISSOLVE 1,907 GRAMS OF POTASSIUM CHLORIDE (KCL), IN A LITRE OF DISTILLED WATER.
15.3.2 LITHIUM CHLORIDE SOLUTION: DISSOLVE 37.3 GRAMS OF LITHIUM CHLORIDE (LICL) IN 100 MILLILITRES OF DISTILLED WATER.
15.3.3 OF
SOLUTIONSPOTASSIUM OF 0, 1, 2, 3, 5, 7 MILLIGRAM/LITRE, PREPARED FROM (15.3.1), AFTER ADDITION OF THE REQUIRED AMOUNT OF LITHIUM CHLORIDE, FOR LITHIUM TO BE FOUND IN A PROPORTION OF APPROXIMATELY 2,000 MILLIGRAM/LITRES.
15.4 PROCEDURE.
CENTRIFUGE AN APPROPRIATE SAMPLE VOLUME.
TAKE 1 CC. OF THE SUPERNATANT AND MAKE THE APPROPRIATE DILUTION WITH DISTILLED WATER (AFTER ADDITION OF THE REQUIRED AMOUNT OF LITHIUM CHLORIDE FOR LITHIUM TO BE IN A PROPORTION OF APPROXIMATELY 2,000 MILLIGRAM/LITRE). READ IN ATOMIC ABSORPTION OR FLAME PHOTOMETRY 766-770 MILLIMETERS IN FRONT OF THE REFERENCE SOLUTIONS.
15.5 CALCULATIONS. THE POTASSIUM CONTENT IS CALCULATED FROM THE VALUE OBTAINED, BY COMPARISON WITH THE STANDARD CURVE, TAKING INTO ACCOUNT THE DILUTION TAKEN.
THE RESULTS ARE EXPRESSED IN MILLIGRAMS OF POTASIO/100 MILLILITRES OF SAMPLE.
15.6 REMARKS:
15.6.1 A 40 GRAM/LITRE SOLUTION OF CESIUM CHLORIDE CAN BE USED INSTEAD OF LITHIUM CHLORIDE, IN THIS CASE THE APPROPRIATE CONCENTRATION OF CESIUM CHLORIDE IN THE DISSOLUTIONS OF THE SAMPLES AND PATTERNS BETWEEN 0.1-0.4 FOR 100.
15.7 REFERENCES:
15.7.1 FEDERATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. METHOD NUMBER 33. YEAR 1984.
15.7.2 METHODS ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS. ED. 1984.
16. SORBICO ACID
16.1 PRINCIPLE. SEPARATION, IDENTIFICATION AND QUANTIFICATION OF SORBIC ACID BY HIGH EFFICACY LIQUID CHROMATOGRAPHY BY DETECTING IT IN ULTRAVIOLET AT 230 NM.
16.2 MATERIAL AND APARATOS:
16.2.1 SAMPLE AND SOLVENT FILTRATION EQUIPMENT, TO REMOVE PARTICLES ABOVE 0.5 M M.
16.2.2 LIQUID CHROMATOGRAPH EQUIPPED WITH VARIABLE WAVELENGTH ULTRAVIOLET DETECTOR AND LOGGER.
16.2.3 COLUMN C-18 OF 250 X 4.6 MM 10 M M OR SIMILAR.
16.2.4 ULTRASOUND BATH.
16.3 REAGENTS:
16.3.1 SORBIC ACID PATTERN SOLUTION IN METHANOL OF 50 MILLIGRAM/LITRE.
16.3.2 PH PHOSPHATE BUFFER SOLUTION = 6.6. DISSOLVE 2.5 GRAMS OF POTASSIUM HYDROGEN PHOSPHATE TRIHYDRATE (K 2 H PO 4 H 2 O) AND 2.5 GRAMS OF POTASSIUM DIHYDROGEN PHOSPHATE (KH 2 PO 4), IN A LITRE OF DISTILLED WATER. FILTER THIS SOLUTION WITH (16.2.1).
16.3.3 METHANOL FOR HPLC.
16.4 PROCEDURE:
16.4.1 GUIDANCE CHROMATOGRAPHIC CONDITIONS:
MOBILE PHASE: METHANOL-BUFFER PHOSPHATE 10: 90 (V/V).
FLOW: 1 MILLIITRO/MINUTE.
16.4.2 CALIBRATED:
INJECT IN THE CHROMATOGRAPH BETWEEN 10 AND 20 M 1 OF THE STANDARD SOLUTION (16.3.1), AND CALCULATE THE RESPONSE FACTOR.
RESPONSE FACTOR (F) =
C 0/A P
SIENIT:
C 0 = CONCENTRATION, IN MILLIGRAMS/LITRES, OF SORBIC ACID.
A P = PEAK AREA IN THE PATTERN SOLUTION CHROMATOGRAM.
16.4.3 DETERMINATION: TAKE 10 MILLILITRES OF JUICE IN A 50 MILLILITER FLASK AND MAKE UP TO THE MARK WITH METHANOL. FILTER AND INJECT 10 AND 20 M1 INTO THE CHROMATOGRAPH.
16.5 CALCULATIONS:
16.5.1 THE SORBIC ACID CONTENT EXPRESSED IN MILLIGRAMS/LITRES (WITHOUT DECIMALS), WILL BE OBTAINED BY THE FOLLOWING FORMULA:
SORBICO ACID (MG/L) = F X TO 1 X F
SIENIT:
F = RESPONSE FACTOR.
A 1 = SORBIC ACID PEAK AREA IN THE SAMPLE.
F = SAMPLE DILUTION FACTOR.
16.6 REMARKS. THE SENSITIVITY CAN BE INCREASED BY PERFORMING READINGS AT 250 NM.
16.7 REFERENCES. T. STIJVE AND HISCHENHUBER. DEUTSCHE LEBENSMITTEL-RUNDSCHAU/80, JAHRG/HEFT 3/1984.
17. BENZOIC ACID
17.1 PRINCIPLE. SEPARATION, IDENTIFICATION AND QUANTIFICATION OF BENZOIC ACID BY HIGH EFFICACY LIQUID CHROMATOGRAPHY, DETECTING IT IN ULTRAVIOLET AT 230 NM.
17.2 MATERIAL AND APARATOS:
17.2.1 SAMPLE AND SOLVENT FILTRATION EQUIPMENT TO REMOVE PARTICLES ABOVE 0.5 MM.
17.2.2 LIQUID CHROMATOGRAPH EQUIPPED WITH VARIABLE WAVELENGTH ULTRAVIOLET DETECTOR AND LOGGER.
17.2.3 COLUMN C 18 OF 250 X 4.6 MILLIMETERS OF 10 MM OR SIMILAR.
17.2.4 ULTRASOUND BATH.
17.3 REAGENTS:
17.3.1 BENZOIC ACID STANDARD SOLUTION IN METHANOL OF 50 MILLIGRAM/LITRE.
17.3.2 PH PHOSPHATE BUFFER SOLUTION = 6.6. DISSOLVE 2.5 GRAMS OF POTASSIUM HYDROGEN PHOSPHATE TRIHYDRATE (K 2 HPO 4 H 2 O) AND 2.5 GRAMS OF POTASSIUM DIHYDROGEN PHOSPHATE (KH 2 PO 4) IN A WATER LITRO. FILTER THIS SOLUTION WITH 17.2.1.
17.3.3 METHANOL FOR HPLC.
17.4 PROCEDURE:
17.4.1 GUIDANCE CHROMATOGRAPHIC CONDITIONS:
MOBILE PHASE: METHANOL-BUFFER PHOSPHATE 10: 90 (V/V).
FLOW:
1 MILLIITRO/MINUTE.
17.4.2 CALIBRATION: INJECT 10 TO 20 ML OF THE STANDARD SOLUTION 17.3.1 INTO THE CHROMATOGRAPH AND CALCULATE THE RESPONSE FACTOR.
RESPONSE FACTOR (F) = C O/A P
SIENIT:
CO = CONCENTRATION, IN MILLIGRAM/LITRE, OF BENZOIC ACID.
AP = PEAK AREA IN THE PATTERN SOLUTION CHROMATOGRAM.
17.4.3 DETERMINATION: TAKE 10 MILLILITRES OF JUICE IN A 50 MILLILITRE FLASK AND MAKE UP TO THE MARK WITH METHANOL. FILTER AND INJECT FROM 10 TO 20 ML IN THE CHROMATOGRAPH.
17.5 CALCULATIONS:
17.5.1 BENZOIC ACID CONTENT EXPRESSED IN MILLIGRAM/LITRE (WITHOUT DECIMALS) SHALL BE OBTAINED BY THE FOLLOWING FORMULA:
BENZOIC ACID (MILLIGRAM/LITRE) = F X TO 1 X F
SIENIT:
F = RESPONSE FACTOR.
A 1 = AREA OF THE PEAK OF BENZOIC ACID IN THE SAMPLE.
F = SAMPLE DILUTION FACTOR.
17.6 REMARKS. THE SENSITIVITY CAN BE INCREASED BY READING TO 217 NM.
17.7 REFERENCES. T. STIJVE AND C. HISCHENHUBER. DEUTSCHE LEBENSMITTEL-RUDSCHAU/80, JAHRG/HEFT 3/1984.
18 (A). SULPHUR DIOXIDE
(PAUL METHOD)
18 (A) .1 PRINCIPLE. RELEASE OF FREE SULPHUROUS AND COMBINED ACIDIFICATION AND SUBSEQUENT HEATING AND OXIDATION BY BORBOTHEUS IN OXYGENATED WATER AND VALUATION WITH SODA OF THE FORMED SULPHURIC ACID.
18 (A) .2 MATERIAL And APARATOS:
18 (A) .2.1 LIEB-ZACHERL APPARATUS AS INDICATED IN FIGU RA 18 (A).
18 (A) .2.2 ALCOHOL MECHERO OR SIMILAR.
18 (A) .2.3 BURBOTER TUBE PROVIDED WITH HOLLOW BALL AT ONE END WITH ABOUT 20 HOLES OF 0.2 MILLIMETERS IN DIAMETER AROUND THE HORIZONTAL MAXIMUM CIRCLE.
18 (A) .2.4 BOTTLE WITH WATER AND PLUG CROSSED BY THE TUBE THAT COMMUNICATES WITH THE BORER TO MAKE VACUUM, AND ANOTHER TUBE SUBMERGED IN WATER TO CHARGE THE INTENSITY OF THE VACUUM DUE TO THE DEPRESSION OF THE WATER COLUMN INSIDE THE WATER. TUBE, DEPRESSION TO BE MAINTAINED BETWEEN 25-35 CENTIMETERS.
18 (A) .2.5 FLASK OF 250 MILLILITRES.
18 (A) .2.6 COOLANT CONDENSING VAPORS AND ALLOW THE GAS TO PASS IN SAFE TRAVEL.
18 (A) .3 REAGENTS:
18 (A) .3.1 FOSFORIC ACID AT 25 PER 100 (P/V).
18 (A) .3.2 OXYGENATED WATER OF 0.3 PER 100.
18 (A) .3.3 INDICATOR: 0.1 GRAMS OF METHYL RED AND 0.05 GRAMS OF METHYLENE BLUE IN 100 MILLILITRES OF ALCOHOL AT 50 PER 100.
18 (A) .3.4 SODIUM HYDROXIDE SOLUTION 0.01 N.
18 (A) .4 PROCEDURE:
100 MILLILITRES OF SAMPLE ARE TAKEN IN THE FLASK OF THE LIEB-ZACHERL APPARATUS. 20 MILLILITRES OF PHOSPHORIC ACID ARE ADDED [18 (A) .3.1] WITH THE FLASK ALREADY ATTACHED TO THE APPARATUS. 2 OR 3 MILLILITRES OF OXYGENATED WATER ARE PLACED IN THE RECEIVING FLASK [18 (A) .3.2]. IT IS EXACTLY NEUTRALISED WITH SODIUM HYDROXIDE [18 (A) .3.4] AFTER TWO DROPS OF THE INDICATOR MIXTURE HAVE BEEN ADDED AND CONNECTED TO THE APPARATUS.
AIR IS ASPIRANT THROUGH THE SOFT-BOILING APPARATUS OF THE SAMPLE FOR 15 MINUTES. THE SO 2 RELEASED IS COLLECTED IN THE RECEIVING FLASK, TRANSFORMING INTO SO 4 H 2 PER ACTION OF THE OXYGENATED WATER.
THIS SULFURIC ACID IS VALUED WITH SODIUM HYDROXIDE SOLUTION (18 (A) .3.4).
18 (A) .5 CALCULATIONS:
MILLIGRAMS SO 2/LITRE = 320 V 1/V2
SIENIT:
V 1 = VOLUME, IN MILLILITRES, OF NAOH N/100.
V 2 = VOLUME, IN MILLILITRES, OF SAMPLE USED.
18 (A) .6 REMARKS:
A) THE HEATING OF THE SAMPLE SOLUTION IS MADE BY MEANS OF A 4-5 CENTIMETER HIGH-FLAME ALCOHOL MECHERO, LOCATED SO THAT THE FLASK IS ONLY TOUCHED BY THE END OF THE FLAME.
B) THE VACUUM PRODUCED BY THE PRESSURE REGULATOR SHALL BE BETWEEN 25 AND 35 CENTIMETRES.
C) THE REFLUX CONDENSER SHALL BE PROVIDED WITH SUFFICIENT COLD WATER.
D) THE DISSOLUTION OF SODIUM HYDROXIDE USED IN THE ASSESSMENT SHOULD BE PREPARED ON A DAILY BASIS.
E) THIS METHOD IS APPLICABLE FOR CONTENTS, IN SULPHUR DIOXIDE FROM 10 MILLIGRAM/LITRE.
18 (A) .7 REFERENCES. METHOD NUMBER 7. FÉDÉRATION INTERNATIONAL DES PRODUCTEURS DE JUS DE FRUITS. YEAR 1968.
