Milk minerals and salts ppt

Presentation on: Minerals of milk and salt
balance theory
Presented by:
M.
Archana
st
January 10, 20181

January 10, 20182
Contents:
 Minerals: major and minor minerals
 Factors associated with variation in salt composition
 Physical equilibrium amongst milk salts
 Physiological roles of milk minerals
 Partitioning of salt constituents and factors affecting it
 Effects of various treatments on salt equilibrium
 Salt balance and its importance in the processing of milk
 Protein mineral interaction
 Distribution and importance of trace elements in milk

January 10, 20183
Minerals:
 The ash content is a measure of the total amount of minerals present within a
food material, where as the mineral content is a measure of the amount of
specific inorganic components present in a food material i.e. after ashing (free
from organic) such as Ca, Na, Mg, K, Cl etc.
 The milk components proteins, fat, lactose, vitamins and minerals are necessary
to nurture the new-born and consequently they contribute to its growth.
 The mineral fraction, which is a small fraction of milk (about 8–9 g/L),
contains cations (calcium, magnesium, sodium and potassium) and anions
(inorganic phosphate, citrate and chloride). In milk, these ions play an important
role in the structure and stability of casein micelles.
 Minerals contribute to the buffering capacity of milk, the maintenance of milk
pH, the ionic strength of milk, and milk osmotic pressure.
(Mccelements, 2009)

January 10, 20184
Determination of ash and mineral content of foods is important
for following reasons:
 Nutritional labeling: The concentration & type of minerals present must often
be stipulated on the label of food.
 Quality: The quality of many foods depends on the concentration & type of
mineral they contain, including their taste, appearance, texture and stability.
 Microbiological stability: High mineral contents are some times used to retard
the growth of certain microorganisms.
 Nutrition: Some minerals are essential to a healthy diet(Ca, Na, Mg, K etc)
where as some are toxic(Pb, Hg, Cd, Ar, Al etc).
 Processing: It is often important to know the mineral content of foods during
processing because this affects the many physicochemical properties of food.
(Mccelements, 2009)

January 10, 20185
Milk minerals are classified as 2 types:
 Major or abundant minerals: sodium, potassium, calcium,
magnesium, phosphates ,citrates, sulphates, chlorides, carbonates
etc.
 Minor or trace minerals: cobalt, copper, iodine, manganese,
nickel, molybdenum, iron, zinc etc.
Jenness, R. and Patton, S. (1959)

January 10, 20186
Major minerals
constituents of milk
Buffalo milk (avg.
content in mg/100g)
Cow milk (avg.
content in mg/100g)
Sodium (Na) 44.63 58.0
Potassium (K) 103.0 140.0
Calcium (Ca) 175.5 123.3
Magnesium(Mg) 19.25 11.1
Phosphorus (total) 97.6 95.1
Phosphorus (inorganic) Trace -
Chloride (Cl) 62.84 104.5
Sulfate (So2 ) - 10.0
Carbonate (as CO2) - 20.0
Citrate (as citric acid) 163.6 176.6
Mathur, M.P., Dattaroy, D., Dinakar, P.(1998)

January 10, 20187
Minor minerals
constituent of milk
Cow milk (µg/L) Buffalo milk (µg/L)
Boron (B) 100-400 0.82 ppm
Zinc (Zn) 1000-6000 600-650
Iron (Fe) 300-350 2000-2400
Copper(Cu) 0.2-1.4 200-220
Sulphur (S) - 200-230 ppm

January 10, 20188
Factors affecting variation in salt composition:
 Breed of animal
 Stage of lactation
 Infection of udder
 Feed
Breed of animal:
Milk from jersey cows usually contains more calcium and
phosphorus than milk from other breeds
P.F.Fox and Mc Sweeney(1998)

January 10, 20189
Stage of lactation:
 The concentration of total calcium is generally high in both early
and late lactation but in the intervening it is constant.
 Phosphorus shows a general tendency to increase as lactation
advances.
 The concentration of colloidal calcium and inorganic phosphorus
are min. in early lactation and max. in late lactation.
 The concentration of sodium and chloride are high at the beginning
of lactation followed by a rapid decrease then increase gradually
until near the end of lactation.
 The concentration of potassium decreases gradually throughout
lactation.

January 10, 201810
Graph showing stages of lactation:
calcium
phosphorus

January 10, 201811
chloride

January 10, 201812
 The conc. of citrate shows a strong seasonal variation.

January 10, 201813
Infection of the udder:
 Milk from cows with mastitic infections contains a low level of total solids, especially
lactose, and high levels of sodium and chloride, the concentration of which are directly
related.
 The sodium and chloride ions come from the blood to compensate osmotically for the
depressed lactose synthesis or vice versa.
 These are related by koestler number which is given by,
 The koestler no. for normal milk is 1.5 – 3.0 if the value is more than this means it
indicates mastitis infection so koestler no is used as index of mastitis infection or infected
udder this is due to change in chloride and lactose content of milk.

January 10, 201814
Feed:
 Feed has little effect on the concentration of most elements in milk.
 The level of citrate in milk decreases on diets very deficient in
roughage and this results in ‘Utrecht phenomenon’, i.e. milk of very
low heat stability.

January 10, 201815
Physical equilibrium among milk salts:
 Milk contains several elements but all of them are not entirely
in a soluble state, some minerals exists in colloidal & ionic
state at normal pH of milk.
 The compounds which are in soluble condition plays an
important role in keeping various milk constituents in stable
condition.
 A balance exists between the components which are in soluble
state and those which are in colloidal state, this makes the
physical equilibrium among milk salts.

January 10, 201816
Salts solution in milk:
 The dissolved salts of milk are phosphate, citrate, chloride, sulphate,
bicarbonate, sodium, potassium, magnesium & calcium.
 Sodium & potassium in milk are present entirely in soluble state.
 Calcium, magnesium, phosphates and citrates present as colloidal
state.
 The chloride and sulphate are entirely present as free ions i.e. Cl- and
SO4
2- at the normal pH of milk.
 Calcium & magnesium form soluble ions with citrate, phosphate &
bicarbonates.

January 10, 201817 Jenness, R. and Patton, S. (1959)

January 10, 201818
Physiological roles of milk minerals:
Some of the important milk minerals are as follows
• Sodium (Na)
• Chloride (Cl)
• Potassium (K)
• Calcium (Ca)
• Phosphorus (P)
• Magnesium (Mg)
• Iron (Fe)
• Zinc (Zn)
• Copper (Cu)
• Manganese (Mn)
• Iodine (I)

January 10, 201819
Physiological roles of sodium and chloride:
• The cation Na and anion Cl are required to maintain extracellular
volume and plasma osmolarity.
• The chloride concn. In bovine milk increases sharply towards end of
lactation.(Eremann et al.,1987).
• Na and Cl are almost believed to be present ion milk as entirely free
form.(Holt, 1993).
• Excessive intake of Na and Cl causes dehydration problems in young
infants. These individuals capacity to concentrate solids is limited &
renal load exerts a major effect on water balance.

January 10, 201820
• Cont..
• Renal solute load is determined by Na, Cl, K, PO4 and protein.
• Bovine milk has a higher potential of renal solute
load(~300mOsmol/L) than human milk (~93mOsmol/L).
• The high renal solute load means kidney excretes a more
concentrated urine, this reduces the margin of safety against
dehydration.
• The upper limit (UL) for renal solute load for young infants should
be about 220mOsmol/L.(Ziegler and foman, 1989).

January 10, 201821
Potassium (K):
• Potassium plays many important roles in body including acid base
balance, maintenance of osmotic pressure & blood pressure,
cellular uptake of amino acids and co-factor activators in many
enzyme system.
• Potassium has critical role in membrane transport, carbohydrate and
energy metabolism.
• Cellular membrane polarization depends upon the internal and
external concn. of potassium.
• If deficiency of potassium causes hypokalemia and excess of
potassium causes hyperkalemia, results in dysfunctioning of
cardiac, muscle & neurological function.(Preuss, 2006).

January 10, 201822
• Hypokalemia includes cardiac arrhythmias, muscle weakness, and
glucose intolerance.(Preuss, 2006).
• Hyperkalemia includes increased blood pressure, salt sensitivity
and bone turn over, cardiac arrest, neuromuscular symptoms like
tangling, parasthesia, weakness and flaccid paralysis.(Preuss, 2006)
• Intracellular fluid potassium accounts for 98% and extracellular
fluid accounts for 2%in the body, plasma potassium accounts
average if it is less it is indicator of poor tissue concentration.
• The average concentration of potassium in mature human milk is
0.5g/L, for bovine milk is 1.5g/L and bovine colostrum is >1.5g/L.
(FNB,2001).

January 10, 201823
• All potassium is absorbed from the digestive tract of
mammals.(Flynn, 1990 and ontsouka et al.,2003).
• Dairy products can be major contributors to total dietary intake of
potassium (24-29%) (Flynn et al., 1990).
• A diet rich in fruits, vegetable and milk would assure a healthy
intake of potassium. (Flynn et al., 1990).

January 10, 201824
Calcium:
• Most abundant mineral in the body(~1000g) (Flavus et al., 2006).
• 1% of total body calcium is found in extracellular fluids in
extracellular fluids, intracellular structures and cell
membrane.(Awumey and Bokoski, 2006, Kirchoff and Geibel,
2006).
• Calcium mediates muscle contraction, nerve transmission and
glandular secretion.
• About 99% of total body calcium is found in bones and teeth's in
which bone crystals contains hydroxyappatite[(Ca10 (PO4 )6 (OH)2].
contributes ~39% calcium.

January 10, 201825
Cont…
• Skeletal tissue is replaced every 10-12 years on an average because
the skeleton is metabolically active organ must undergo continuous
remodeling to adopt internal microstructure.(Heaney, 2006).
• Bone is renewed continuously to repair micro damage to minimise
the risk of fracture (Gracia –Aznar et al., 2005).
• Deficiency of calcium causes rickets,(Davidovitis et al.,2006) and
age related osteoporosis.(Harvey et al., 2006)
• A distinguishing characteristic between osteoporosis and
osteomalacia is a normal mineral to collagen ratio. (Looker et
al.,1993)

January 10, 201826
As per RDI, values for calcium intake are given in table:
• As per ICMR calcium requirement for adults is
400mg/day(Harinarayan et al., 2007).
• The upper limit(UL) for calcium is 2500mg/day
Age in years Quantity intake in mg/day
0-12 months 525
1-3 years 350
4-6 years 450
7-10 years 550
11-18 years 1000(for males )
800(foe females)
> 19 years 700
Source: Recommended dietary intake

January 10, 201827
Phosphorus:
• Phosphorus is an essential nutrient for humans and an adult body
contains about 850g of elemental phosphorus with 85% in skeletol,
14% in soft tissue, 1% in intra and extracellular fluids and cell
membrane.(Anderson et al., 2006)
• Food phosphorus is mixture of both inorganic and organic
phosphorus. (Anderson et al., 2006)
• The dietary phosphorus present as phytate form, the storage form of
phosphorus.
• Phosphorus bioavailability depends on hydrolysis of phytate by
phytase enzyme produced by yeasts and colonic bacteria.
(Anderson et al., 2006)

January 10, 201828
Cont..
• Organic phosphates are major components of phospholipids,
nucleotides and nucleic acids.(Anderson et al., 2006)
• Dietary phosphorus deficiency causes hypophosphatemia (FNB,
1997) also causes anorexia, anemia, muscle weakness, bone pain,
rickets, and osteomalacia, parasthesia, confusion and even
death.(Lotz etal.,1968)
• Hypophosphatemia also causes calcification of non skeltol tissues
(a condition that occurs when calcium & phosphorus concentration
of extracellular fluid exceeds limits of Ca and PO4) solubility, and
finally leading to mortality and cardiovascular and vascular
calcification.(Korienga, 2007)

January 10, 201829
• Dietary phosphorus derived mainly from foods high in protein or
from foods where phosphates salts are added.
• Phosphorus intake by DRI is 300- 600mg/day (FNB, 1997).
• In bovine milk about 54% of inorganic phosphorus is soluble and
about 46% is associated with casein micelles as calcium phosphate.
(FNB, 1997).

January 10, 201830
Magnesium:
• Magnesium is most prevalent intracellular divalent cation and is
needed for enzymatic reactions vital to every metabolic
pathway(FNB, 1997).
• Magnesium regulates intracellular calcium and potassium at the cell
membrane level and thus a controlling factor in nerve transmission,
skeletal and smooth muscle contraction, cardiac excitability,
vasomotor tone, blood pressure and bone turnover.
• Severe magnesium deficiency usually the result of dysfunctional
states causing malabsorption or excessive excreation results in loss
of appetite, nausea, vomiting, fatigue and weakness.

January 10, 201831
• As deficiency is more severe causes numbness, tingling, muscle
contraction and cramps seizures, personality changes and coronary
spasms occurs.
• Low intake of Mg also causes dysfunctions such as hypertension &
dysrhythmias, bone loss leading to osteoporosis.
• RDA value for Mg intake is 237mg/day.
• A concentration of Mg in bovine milk is 100mg/L human milk is
34mg/L(Hunt and Meacham, 2001).
• Green leafy vegetables, whole grains & nuts are richest source of
Mg where as milk and milk products are moderate source of
Mg.(Volpe, 2006).

January 10, 201832
Iron:
• Biological systems utilize the chemical reactivity of iron and
interconvert iron oxidation states, thus helps ion electron transport .
• Approx. 66% of Fe found is in hemoglobin of circulating
erythrocytes, 25% in mobilizable iron, 15% in myoglobulin of
muscle tissue.
• In humans there are 4 major iron containing proteins they are
• a) heme protein (hemoglobin, myoglobin, cytochrome)
• b) iron sulphur enzyme (flavoprotein, hemeflavoprotein)
• c) iron transport and storage protein (lactoferrin, transferrin,
ferritin, hemosederin).
• d) iron containing activated enzymes (sulphur, non heme enzyme).

January 10, 201833
• Deficiency of iron causes anemia as, tiredness, apathy and general
feeling of lack of energy, reduction in muscle functioning,
pathological changes in CNS(Beard, 2001)
• Iron deficiency also causes inflammation of tongue(glossitis),
fissuring in the corner of lips(angular stomatitis), spoon nails, blue
sclera, esophagus webbing and behavior disturbances.
• Ferritin and hemosiderin are a water insoluble forms of iron present
in liver. (Beard, 2001)
• Iron requirements are higher during pregnancy.
• The regulation of iron absorption changes between 6-9 months of
age (Domeloff et al., 2002).

January 10, 201834
• A higher number of mammary transferrin receptors facilitates the
uptake of iron into the gland& ensures a normal iron level in
milk.(Lonneldal, 1997).
• The hepatic antimicrobial peptide, hepcidin plays a key role in the
negative feed back regulation of intestinal iron absorption.(Ward
and Connelly, 2004).
• Lactoferrin is a highly efficient mammalian iron scavenging
defense protein (glycoprotein) high association constant for
iron.(Weinberg, 2007).
• Human milk, bovine milk and milk products are poor sources of
iron.(Pennington etal., 1987).

January 10, 201835
Zinc:
• Due to its stability it performs catalytic, structural regulatory
functions in proteins, nucleic acids, carbohydrates, lipid
metabolism.(FNB, 2001).
• Approx. 300 enzymes contains zinc and it has catalytic role in all
the 6 classes of enzymes.
• Zinc regulates expression of some genes.
• Zinc is relatively nontoxic element but >100mg/day results in
impaired immune system, decreased HDL cholesterol and gastric
distress(FNB, 2001).

January 10, 201836
• About 95% body zinc present in intracellular and 40% found in
nucleus and plasma contains 0.1% of zinc and about 85% total zinc
is in skeletal muscle and bone(FNB, 2001).
• In humans plasma zinc is reduced in severe zinc deficiency(FNB,
2001).
• Zinc concentration in bovine milk is 4.0-7.4mg/ltr(Hamill etal,
1989)
• Dairy products are modulate source of zinc (19-31%) as milk,
cheese &yoghurt(Hazell etal., 1985)

January 10, 201837
Copper:
• It is a metal center for about 10 enzymes that binds oxygen and
produce water, superoxide, H2O2 and energy production.
• Copper helps in iron absorption, & utilization, extracellular matrix
maturation, neuropeptide activation and neurotransmits
synthesis(FNB, 2001)
• Deficiency of copper causes malnutrition with chronic diarrhea,
hormocytic hypochromic anaemia, leucopenia, neuropenia,
osteoporosis & in severe deficiency ease causes genetic disorders;
Menke’s syndrome, etc.

January 10, 201838
 Acute excessive copper intake causes gastrointestinal disorders,
abdominal pain, cramps, nausea, diarrhea, vomiting(FNB, 2001)
 Use of copper contaminated water also causes liver damage & liver
Cirrhosis(Tanner, 1998)
 Human body contains 1mg copper/kg body wt(Prohaska, 2006)
 Concentration of copper in bovine milk is 60- 90µ/L & human milk
is 250µg/L (Fransson etal., 1983)
 Milk and milk products are considered as poor source of copper
(Pennington etal., 1987)

January 10, 201839
Manganese:
• Manganese functions as an enzyme activator and is a constituent of
several metalloenzymes(Leach & Harris, 1997)
• All 6 groups of enzymes are activated by presence of Mn.
• Deficiency of Mn causes bone demineralization, poor growth,
decreased plasma cholesterol level, increases serum alkaline
phosphatase activity, osteoporosis, diabetic epilepsy,
atherosclerosis, impaired wound hearing &cataracts(Wedler, 1994)
• Concentration of Mn in human milk 4mg/ltr, & bovine milk is
30µg/ltr(FNB, 2001)

January 10, 201840
• In human milk 67% Mn bound to lactoferrin & in bovine milk 67%
Mn bound to casein (Lonnerdal etal., 1985)
• Milk and milk products are poor source of Mn.
Iodine:
• Iodine plays an important role in thyroid hormone, &this hormones
stores 70-80% of total body iodine.
• Thyroid gland is attached to glycoprotein & thyroglobin to produce
Monoiodotyrosin(MIT) & diiodotyrosin(DIT)

January 10, 201841
• Acts as precursors for thyroid hormone.
• Enzymatic degradation produces T3&T4 forms of which T3 is more
active form hormone(Zimmermann, 2006)
• Thyroid hormone important in regulating basal metabolic rate,
brain development.
• Deficiency of iodine causes loss of energy, mental retardation,
hypopthyrodism, goiter, cretinism &various abnormalities. Most
severe is damage to reproduction system.
• Thyroid is only source for brain &fetus development. So, if
deficiency causes complications during pregnancy causes
incidence of still births ,abortions , congenital abnormalities ,

January 10, 201842
Cont..
• Mental retardation (Auso etal, 2004)
• Iodine in bovine milk is naturally secreted &presence as inorganic
iodide(Miller etal., 1975)
• The concentration of iodine is higher in whey cheeses than in casein
chesses(Dahl etal., 2003)

January 10, 201843
Type of
minerals
Functions
Calcium(Ca) Formation of teeth and bones
Phosphorus(Ph) Synthesis of DNA and bone
Sodium(Na) Regulates body fluid, maintain pH
Magnesium(Mg) Cofactors for metabolic enzymes
Potassium(K) Regulates heart beat and membrane
Zinc(Zn) Boosts body immunity and heals wounds
Iron(Fe) Transformation of oxygen
Copper(Cu) Metabolism of iron and enzymes
Selenium(Se) Functioning of antioxidants enzymes
Important Functions of minerals

January 11, 201844
Partitioning of milk salts and factors affecting it:
• The distinction between the states of solution and colloidal
dispersion results from arbitrary drawing the line at some point of
particle size defined by method used for separation is called
partitioning of milk salts.
• Certain milk salts like chlorides and other salts of Na, K are
sufficiently soluble and present entirely in dissolved state.
• The concentration of others, in particular calcium phosphate is
higher in solution at normal pH of milk, these exist partly in soluble
form and partly in insoluble or colloidal form with casien.
• The partition of these salts and distribution has been extensively
reviewed by Pyne (1962) and Holt (1985).

January 10, 201845
• The dividing line between the soluble phase is arbitrary and its
position depending very much on method used to achieve
separation.
Methods used to separate the colloidal and soluble phases:
• Pressure ultra filtration
• Equilibrium dialysis
• High speed centrifugation
• Rennet / papain coagulation

January 10, 201846
Pressure ultra filtration:
 It involves forcing some of the dissolved phase of a sample of milk
through a fine pored filter by means of pressure.
 Clay, porcelain, collodion and cellophane filters have been used for
this purpose.
 The pore size of such filters is as small enough to prevent the
passage of any smaller colloidal particles.
Equilibrium dialysis:
 It involves dialyzing at small amount of water against a large
amount of milk until equilibrium is reached.

January 10, 201847
Cont..
• Equilibrium dialysis can be conveniently done with cellophane
membrane.
• The material then within the sac at the completion of equilibrium
dialysis represents a sample of dissolved phase of milk.
• It is essential in using this technique that the amount of water be
kept small in comparison to the amount of milk to avoid any undue
dilution.

January 10, 201848
High speed centrifugation:
• It can be used to sediment the colloidal particles and leave the
dissolved phase as a supernatant by using high speed of
centrifugation.
Rennin or Papain coagulation:
• This type of separation can be obtain by treating the small amount
of rennin or papain enzyme which coagulates the colloidal caseinate
particles.
• The sera obtain by the centrifugation or by rennet coagulum contain
whey protein but the sera obtained by the UF or ED do not contain
these serum proteins.

January 10, 201849
Distribution of salts between dissolved and colloidal state in milk:
• In general about 1/3rd of calcium, 1/3rd of phosphate 75% of
magnesium, 90% citrate present in milk as dissolved state.
Type of salts Total in
mg/100ml of
milk
Dissolved state
in mg/100ml of
milk
Colloidal state
in mg/100ml of
milk
Calcium 132.1 51.8 80.3
Magnesium 10.8 7.9 2.9
Total phosphorus 95.8 36.3 59.6
Citrate (as citric acid) 156.6 141.6 15.0
Source: Verma and Sommer(1992)

January 10, 201850
Effects of various treatments on salt equilibrium of milk:
• Effect of change in temperature
• Effect of addition of acid or alkali
• Effect of variation in CO2 content
• Effect of variation in dilution and concentration
• Effect of freezing
• Effect of sequestering agents
• Effect of variation in pH induced by temperature

January 10, 201851
Effect of change in temperature:
• The temperature will shift in the balancing among the various forms
as milk is subjected to various heating and cooling treatments after it
is drawn from udder at37ºC.
• As rise in temperature causes dissolved salts in milk are transferred
to colloidal state so the solubility of the calcium & phosphate
decreases.
• On lowering the temperature below the milk which is drawn from
the udder would cause a transfer of calcium & phosphate from
colloidal to soluble state.

January 10, 201852

January 10, 201853
Effect of addition of acid or alkali:
• The addition of acid or alkali to milk either directly or indirectly by
bacterial action or by heat treatment causes pronounced shift in the
salt equilibrium.
• As the pH decreased by addition acid or alkali the calcium and
phosphate withdrawn from the colloidal particles until as about
pH 5.2 all of calcium and phosphate is in dissolved state.

January 10, 201854 P.F.Fox and Mc Sweeney(1998)

January 10, 201855
Effect of variation in CO2 content:
• Milk as secreted from the cow contains 20mg of CO2/100ml or
about 10% by volume.
• The gas is rapidly lost from milk owing to the low content of acid
which is irreversible.
• Loss of CO2 from milk is accelerated by heating and agitation of
milk.
• Removal of CO2 and the consequent rise in pH would shift in
calcium phosphate from dissolved to colloidal state and also shift in
ions activity.

January 10, 201856
Effect of variation in dilution and concentration:
• Milk is saturated with calcium and phosphate dilution reduces the
concentration of Ca2+ and HPO4
2- and causes solutions of some
colloidal calcium phosphate making milk more alkaline.
• Concentration of milk causes precipitation of colloidal phosphate
and shifts the reaction of milk to acidic side.
• For eg: the concentration by a factor 2:1 reduces the pH to 6.2

January 10, 201857
Effect of freezing:
• Freezing the milk causes crystallization of pure water and unfrozen
liquid becomes more saturated with respect to various salts.
• Some soluble calcium phosphates precipitates as Ca9 (PO4)2 with
release of H+ ions and decrease in pH
• Crystallization of lactose as ɑ-monohydrate also causes some of the
bond minerals to freeze.
• The combination of the increased concentration of Ca2+ and reduced
pH causes destabilization of casein micelles.

January 10, 201858
Effect of sequestering agents:
• The addition of phosphate or citrate to stabilize milk against
subsequent heat coagulation.
• Addition of phosphate or citrate results in the binding of more of
calcium in form of soluble calcium complex and decreasing the
activity of calcium ions.
• The soluble reagents thus helps in ties up particular types of ions are
called sequestering agents and are said to be sequester that ion.
• For eg: commonly used sequestering reagent is EDTA it is very
good reagent for divalent and polyvalent cations.

January 10, 201859
Effect of variation in pH induced by temperature:
• pH of milk is changed following heating due to changes in two salt
systems(dissolved and colloidal).
• Fresh milk contains 200mg/L of CO2 but 50% of this loss is lost due
to standing with additional loss on heating this results in decrease in
titrable acidity and increase in pH .
• The formation of colloidal calcium phosphate during the heating
more than compensates for loss of CO2.

January 10, 201860
Changes in pH induced by change in temperature:
Temperature in
ºC
Change in pH
20 6.64
30 6.55
40 6.45
50 6.34
60 6.23
Source: P.F.Fox and Mc Sweeney(1998)

January 10, 201861
References:
Text book of dairy chemistry
- M.P. Mathur
- D.Datta Roy
- P. Dinakar
Text book of dairy chemistry
- Robert Jenness
- Stuart Patton
Text book of dairy chemistry and biochemistry
- P.F.Fox
- P.L.H. Mc Sweeney

Milk minerals and salts ppt

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