Dry Matter Food Analysis

DRY MATTER AND ASH EXPERIMENT

This webpage is designed to show you how you can measure the dry matter content within a given animal food product which will identify the level of moisture within this feed type.

Aim of Experiment

TO IDENTIFY THE WATER CONTENT WITHIN A DRY DOG FOOD

Resources

EXQUIPMENT NEEDED:

  • SCALES
  • METAL DISH
  • BUNSEN BURNER
  • HEAT MAT
  • GLASS ROD
  • CLAMPS
  • OVEN
  • GAUZE
  • BEAKER
  • CRUCIDAL
  • PIPECLAY TRIANGLE

DOG FOOD

• WAINWRIGHTS PUPPY FOOD (TURKEY AND RICE)

Health and Safety

SAFTETY PRECAUTIONS WHICH MUST BE FOLLOWED

  • TIE LONG HAIR BACK
  • WEAR PPE (PERSONAL PROTECTIVE EQUIPMENT) TO PROTECT CLOTHING AND EYES FROM FLAMES AND PREVENT HOT ASH BLOWING INTO EYES AND MASKS TO REDUCE TO THE INHALATION OF CHEMICAL FUMES.
  • USE TEST TUBE PEGS TO PREVENT BURING FINGERS
  • ENSURE ALL BAGS AND COATS ARE PUT AWAY TO REDUCE SLIPS, TRIPS AND FALLS

Method

STEP BY STEP GUIDELINES

FIRSTLY YOU NEED TO WEIGH THE METAL DISH ON ITS OWN, THEN ADD A SMALL PORTION OF FOOD BETWEEN 5-10G TO THE DISH, NO MORE OTHERWISE IT WILL TAKE TOO LONG TO BREAK DOWN. THIS WILL GIVE YOU AN OVERALL WEIGHT, YOU MUST THEN TAKE THE WEIGHT OF THE DISH FROM WEIGHT OF FOOD AND THE BOWL, THIS WILL PROVIDE YOU WITH THE EXACTLY WEIGHT OF YOUR FOOD CONTENT FOR EXAMPLE;

  • DISH WEIGH = 2.8G
  • WEIGHT OF DISH WITH FOOD = 8G
  • CALCULATION = 8 - 2.8

    = 5.2G

    SO FOOD WEIGHS 5.2G

YOU MUST CLEARLY LABEL YOUR DISH WITH THE  NAME OF THE FOOD AND THE OVERALL WEIGHT OF THE FOOD (8G)

YOU THEN PUT THE SAMPLE INTO THE OVEN WHICH MUST BE SET AT 100-106C, FOR A PERIOD OF 2 HOURS

AFTER THE 2 HOUR PERIOD, ALLOW THE DISH TO COOL AND THEN RE=WEIGH THE DISH AND FOOD TOGETHER, THEN YOU CAN CALCULATE HOW MUCH MOISTURE THE FOOD CONTAINED, BY USING THE FOLLOWING FORMULA:

BEFORE WEIGHT (FOOD AND DISH TOGETHER) 8G

AFTER WEIGHT (FOOD AND DISH TOGETHER) 7.6G

= 0.4G OF MOISTURE

YOU MUST THEN CALCULATE THIS MOISTURE CONTENT INTO A PERCENTAGE AND THIS IS DONE USING THE FOLLOWING CALCULATION

RESIDUE WEIGHT – FOOD AMOUNT

0.4 - 5.2

= 0.076

YOU MUST THEN MULTIPLY THIS BY 100

0.076 X 100

= 7.6% MOISTURE CONTENT

YOU CAN ALSO FURTHER TEST THE ASH CONTENT WITHIN THE FOOD, THIS CAN BE DONE BY:

PLACING THE CRUCIBLE ON THE SCALES AND WEIGHING IT,(EXAMPLE 16.3 G (WITHOUT FOOD), AND PUT IN A SAMPLE OF FOOD FROM THE PREVIOUS TEST (OVEN) AND WEIGH (EXAMPLE 19.1G), WHICH INDICATES THE OVERALL WEIGHT (28G)

PLACE THE CRUCIBLE ON TO THE TRIANGLE AND USING A BUNSEN BURNER BURN UNTIL ITS ASH, THIS MAY TAKE SOME TIME.

THE FIRST INITIAL STEP IS THAT YOU SHOULD SEE A FLAME, DON’T BE ALARMED THIS IS JUST THE FAT BEING BURNT AWAY, WHICH CAUSES THIS CHEMICAL REACTION.

WITHIN 3 MINS THE FOOD SHOULD TURN BLACK

AFTER A FURTHER 5 MINS THE FOOD WITH AGAIN BEGIN TO BURN AND PRODUCE A FLAME, THIS SHOULD LAST FOR A MAXIMUM OF 3 MINS, AND THEN BLACK CHALK-OLE LIKE CLUMPS WITH APPEAR, CONTINUE TO BURN THESE, THIS MAY TAKE UP TO 19 MINS, BUT AFTER 15 MINS SMALL AMOUNTS OF ASH SHOULD BEGIN TO FORM, IT WILL TAKE A FURTHER 17 MINS UNTILL THE WHOLE OF THE FOOD IS ASH. ALLOW THIS TO COOL AND THEN REWEIGH (16.6G)

TO CALCULATE THE ASH CONTENT YOU CAN USE THE FOLLOWING CALCULATION

RESIDUE WEIGHT OF ASH – DISH WEIGHT

16.6 – 16.9

= 0.3

TOTAL WEIGHT – DISH WEIGHT

19.1 – 16.3

= 2.8

= 0.107

X 100

= 10.7% ASH CONTENT

Variables

THERE IS A VARIETY OF FACTORS WHICH COULD INFLUENCE THE OUTCOME OF THESE EXPERIMENTS THESE CAN BE IDENTIFIED AS DEPENDANT, INDEPENDENT AND FIXED VARIABLES.

DEPENDANT VARIABLES: THE THINGS YOU AS THE REASEARCHER CAN MEASURE

  • HOW LONG FOOD IN THE OVEN
  • TEMPRATURE OF THE OVEN

INDEPENDANT VARIABLES: THESE ARE THINGS WHICH CAN BE CHANGED TO INFLUENCE THE RESULTS

  • QUANTITIES / TYPES OF FOOD
  • HOW LONG THE DRY MATTER IS BURNT (VARIED FAT CONTENTS- LONGER BURNING TIME)
  • FIXED VARIABLES: THESE ARE FACTORS WHICH ARE KEPT THE SAME EACH TIME THE EXPERIMENT IS CARRIED OUT TO ENSURE ACCURATE AND VALID RESULTS, THIS COULD INCLUDE TEMPRATURE, EQUIPMENT, METHOD USED.

    Predictions

    MY PREDICTIONS FOR THIS EXPERIMENT WOULD BE THAT THE COMPLETE DRY FOOD WILL CONTAIN AN INCREASED LEVEL OF MOISTURE DUE TO THE AMOUNT OF VEGTABLES AND NATURAL INGREDIANTS THE COMPLETE FOOD CONTAINS, THE PACKAGE DETAILS THE MOSITURE CONTENT AT 10%. I ALSO PREDICT THE ASH CONTENT WILL BE HIGHER THAN STATED DUE TO THE SAME REASON, THE PACKAGING QUOTES THE FOOD AS HAVING 6% ASH.

    Results

    THE RESULTS AS SHOWN IN THE CALULATION ABOVE SHOW THAT WAINTWRIGHTS PUPPY FOOD CONTAINS 7.6% MOISTURE, WHICH IS A LOT LESS THN STATED ON THE PACKAGING AS 10%. HOWEVER THE EXPERIMENT INDICATED A HIGHER THAN EXPECETED AMOUNT OF ASH WHICH WAS 10.71% COMPARED TO THE PACKAGING WHICH STATES 6%, AS CAN BE SEEN BELOW;

    “Typical Analysis: Protein 27%, Crude Fibre 3.5%, Oils and Fats 14%, Crude Ash 6%, Moisture 10%. Feeding Guide (approximate per day) Large: (25 - 45kg)”

    (Pets At Home, 2015)


    Conclusion

    I BELIEVE THAT THE INCREASED IN ASH CONTENT COULD BE DUE TO TWO FACTORS, ONE BEING THAT THE FOOD WASN’T BURNT FOR LONG ENOUGH AND THEREFORE ALL CONPONENETS WHERE NOT COMPLETELY BURNT, AND ALSO THAT THE FOOD HAS AN HIGHER THAN EXPECTED ASH CONTENT DUE TO VAST AMOUNT OF NATURAL INGREDINTS INCLUDING VEGTABLES AND CEREAL AND GRAINS WHICH HAVE A HIGH MINERAL CONTENT ( McClements, 2012).

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