2.1 . BEAKER, CAPACITY 250 ML TO 1 000 ML .
2.2 . DISHES MADE OF SILICA, PORCELAIN OR PLATINUM .
2.3 . ASHLESS FILTERS .
2.4 . PEAR-SHAPED SEPARATING FUNNEL, 2-LITRE CAPACITY WITH WIDE-DIAMETER TAP ( SEE FIGURE ).
2.5 . MUFFLE FURNACE SET AT 500 TO 600 *C .
2.6 . DRYER .
2.7 . ANALYTICAL BALANCE .
3 . PROCEDURE
WEIGH INTO A BEAKER A QUANTITY OF PRODUCT CORRESPONDING TO 300 R G, +/- 0,01 G WHERE R REPRESENTS THE NTSS ( NATURAL TOTAL SOLUBLE SOLIDS ) CONTENT . ADD BETWEEN 100 AND 150 ML WATER . MIX WELL . POUR INTO THE 2-LITRE SEPARATING FUNNEL, WHICH SHOULD BE PARTLY FILLED WITH WATER, AND SET THE ADJUSTABLE TUBE SO THAT ITS LOWER END IS AT LEAST HALF-WAY DOWN THE BULB . ALLOW WATER TO FLOW INTO THE FUNNEL AT A RATE THAT CAUSES SUFFICIENT TURBULENCE TO SEPARATE THE MINERAL SUBSTANCES FROM THE PULP . REMOVE THE PULP IN SUSPENSION WITHOUT REMOVING THE SAND; FOR THIS PURPOSE THE ADJUSTABLE TUBE SHOULD BE LOWERED TOWARDS THE BOTTOM OF THE SEPARATING FUNNEL .
CONTINUE THE OPERATION UNTIL ONLY THE MINERAL IMPURITIES REMAIN AT THE BOTTOM OF THE FUNNEL . NOTE THAT THE RESIDUE MAY SOMETIMES ALSO CONTAIN HEAVY ORGANIC WASTE SUCH AS TOMATO SEEDS .
PLACE THE SEPARATING FUNNEL OVER A FUNNEL HAVING AN ASHLESS FILTER AND STRAIN ALL THE RESIDUE THROUGH THE FILTER OPENING THE SEPARATING FUNNEL TAP AND FLUSHING OUT AS NECESSARY WITH WATER . RINSE THE FILTER WITH DISTILLED WATER, THEN PLACE THE FILTER PAPER AND RESIDUE IN THE INCINERATING DISH . DRY THE DISH, RESIDUE AND FILTER, THEN CHAR OVER A LOW FLAME AND FINALLY INCINERATE IN THE MUFFLE FURNACE AT 500 TO 600 *C FOR 30 MINUTES .
ALLOW TO COOL IN THE DRYER AND WEIGH ACCURATELY TO WITHIN 0,0002 G .
AT LEAST TWO DETERMINATIONS MUST BE CARRIED OUT ON THE SAMPLE . THE PERCENTAGE BY MASS OF MINERAL IMPURITIES IS GIVEN BY
( M1 - MO ) X 100 E ,
WHERE :
MO IS THE MASS OF THE DISH IN GRAMS,
ML IS THE MASS OF THE DISH AND ASH IN GRAMS,
E REPRESENTS THE DRY WEIGHT CONTENT OF THE SAMPLE .
DIAGRAM OF APPARATUS USED FOR CONTINUOUS SEPARATION OF WATER-INSOLUBLE MINERAL IMPURITIES
TUBE OF ADJUSTABLE HEIGHT
*
LIQUID REMOVED*
SAND
PH
1 . PRINCIPLE
THE PH OF TOMATO DERIVATIVES IS DETERMINED ELECTROMETRICALLY USING A PH METER .
2 . APPARATUS
2.1 . PH METER .
2.2 . REFERENCE AND PH ELECTRODES OR COMBINED ELECTRODE .
2.3 . BUFFER SOLUTIONS PH = 4,0 AND PH = 7,0 .
3 . PROCEDURE
3.1 . CALIBRATE THE PH METER USING THE BUFFER SOLUTIONS .
3.2 . MEASURE THE TEMPERATURE OF THE PRODUCT USING A THERMOMETER AND SET THE INSTRUMENT TO THAT TEMPERATURE .
3.3 . INSERT THE ELECTRODES OR COMBINED ELECTRODE INTO THE UNDILUTED TOMATO PRODUCT .
4 . EXPRESSION OF RESULTS
THE PH IS SHOWN DIRECTLY BY THE APPARATUS .
CALCIUM-ION CONTENT
1