Comparison of Different Methods for Determining Water Content in Butter

and Light Butter

Bernisa Klepo

University of HohenheimInstitute of Food Science and

Biotechnology

University of SarajevoFaculty of Agriculture and Food Science

Introduction

Water content

Different methods for water content determination

Butter and Light Butter - Problems

Inhomogeneous distribution of water

Flocculation in the light products

Strong flocculation in Du Darfst butter – more comlex composition (gelatin, starch)

Problems with covering of electrode

Drying TechniquesWeight loss

Evaporation of all volatile material→ too high results

Strongly bound water → too low results

Long measuring times and accurate sample handling

Rapid techniquesVigorous heating → risk of producing additional volatile material

Karl Fischer Titration

Highly selective to water

Fast analysis

Accurate

Precise

Samples

Sample Ingredients Water (%)

Conventional butter - Die MEGGLE

Alpenbutter Water, Carbohydrates, proteins, fat 16,2

Light butter - Du Darfst

Water, buttermilk (11%), gelatin, modified starch, emulsifier: mono-and diglycerides of fatty acids, salt (0.25%), preservative:potassium sorbate, citric acid regulator of acidity, flavour, dye carotene 57,4

Light butter -Linessa

Water, milk fat, buttermilk, emulsifiers: mono-and diglycerides of fatty acids, polyglycerol polyricinoleate, 0.7% acidity regulator: sour milk, preservatives: potassium sorbate, natural flavor, dye: beta-carotene 60,3

Oven drying

A standard gravimetric method described by European Community was applied

drying oven FD 115 from Binder, Tuttlingen Germanyaprox. 2 g of sample102 ± 2 °Cmass loss

Microwave Drying

SMART turbo from CEM, Matthews, N.C., U.S.AMaximal powerDelta weight: 0,1 mgDelta time: 10 sMax. Time: 10 minMax temp:100 and 120 °CGlass-fibre sample pads

Halogen Drying

The Moisture Analyser HR 73 from Mettler- Toledo

Aluminium dish with glass-fibre pads

Gentle mode

Stop criterion: time – 16 min

Ramp time: 2 mins

Volumetric Karl Fischer Titration

KF Titrando 841 from Metrohm, with titration stand 703

Two-component technique with Hydranal – Titrant 5 and Hydranal – Solvent with additional solvents as a working medium

40 °CPolarising current 50 µAStop voltage 250 mVStop criterion DriftStop drift 10 µl/minMaximal titration rate 4 ml/minMinimal volume increment Minimal µl

KFT in boiling methanol

Appropriate titration cell

The one-component reagent, Hydranal®-Composite 5 andHydranal®-Methanol dry

Polarising current 50 µA

Stop voltage 250 mV

Stop criterion Drift

Stop drift 15 µl/min

Maximal titration rate 2.5 ml/min

Minimal volume increment Minimal µl

Evaluation of the Recovery

Validation of the methods:The evaluations of the added and determined water volume made through linear regressionSlope of the regression lineIntersection of the x-axisRecovery rate

Method nWater content (%)

X± SD SEM t-test p

Drying 3 16,54±0,11 0,06

'Halogen'' drying 10 15,90±0,21 0,07 7,06 VHS

Microwave heating 10 15,61±0,18 0,06 10,95 VHS

KFT conventional 10 15,71±0,22 0,07 8,91 VHS

KFT with hexanol 10 15,63±0,23 0,07 9,32 VHS

KFT with octanol 10 15,63±0,17 0,05 11,11 VHS

KFT with chloroform 10 16,42±0,22 0,07 1,35 NS

KFT with toluene 10 15,52±0,36 0,12 7,83 VHS

KFT with hexanol - solute 10 16,23±0,03 0,01 4,95 VHS

KFT with octanol - solute 10 16,33±0,29 0,09 1,91 NS

KFT – boiling methanol 6 17,08±0,65 0,26 7,65 VHS

N – Number of replicates, SD – Standard deviation, SEM – Standard error, P – in relation to drying method, NS – without significant difference, VHS – very high significant difference

Table 1. Water content in conventional butter by different methods

ResultsConventional Butter

ResultsConventional Butter

02468

101214161820

Oven d

rying

Halogen

dryin

gMicr

owav

eKFT co

nv.

KFT + hexano

lKFT + octa

nol

KFT + chlor

oform

KFT + tolue

ne

KFT + hexano

l - so

l.

KFT + hexano

l - so

l.

Fig.1 Water content in conventional buter by different methods

Method nWater content (%)X±SD SEM t-test p

Drying 5 56,78±0,47 0,21

'Halogen'' drying 10 55,33±1,43 0,45 5,79 VHS

Microwave heating 100°C 10 55,85±0,22 0,07 4,15 VHS

Microwave heating 120°C 10 55,79±0,25 0,08 4,36 VHS

KFT Conventional 10 53,08±3,49 1,11 3,28 HS

KFT with Hexanol 10 56,21±2,12 0,67 0,79 NS

KFT with Octanol 10 54,37±0,76 0,24 7,53 VHS

KFT with Chloroform 10 59,45±2,43 0,77 3,35 HS

KFT with Toluene 10 59,76±1,99 0,63 4,49 VHS

KFT with hexanol - solute 10 56,42±0,29 0,09 1,56 NS

KFT with octanol - solute 10 55,93±0,19 0,05 3,85 HS

KFT - Boiling methanol 6 57,67±0,49 0,19 3,08 HS

ResultsLight butter - DuDarfst

Table 2. Water content in light butter DuDarfst by different methods

N – Number of replicates, SD – Standard deviation, SEM – Standard error, P – in relation to drying method,NS – without significant difference, VHS – very high significant difference, HS – high significant difference

ResultsLight butter – Du Darfst

010203040506070

Oven dryi

ngHalo

gen dryi

ngMicr

owave

Microw

ave 12

0KFT co

nv.KFT + hexan

olKFT + octa

nolKFT + ch

loroform

KFT + toluen

e

KFT + hexanol -

sol.

KFT + hexanol -

sol.

Fig.1 Water content in light butter DuDarfst by different methods

Method nWater content (%)X±SD SEM t-test p

Drying 5 59,42±0,23 0,1

'Halogen'' drying 10 58,42±0,34 0,11 6,7 VHS

Microwave heating -100 °C 10 58,48±0,37 0,12 5,97 VHS

Microwave heating -120 °C 10 58,81±0,26 0,08 4,56 VHS

KFT Conventional 10 55,57±0,22 0,07 30,61 VHS

KFT with Hexanol 10 59,25±1,39 0,44 0,37 NS

KFT with Octanol 10 57,97±2,07 0,65 2,19 S

KFT with Chloroform 10 60,68±1,32 0,42 2,92 S

KFT with Toluene 10 58,26±1,09 0,34 3,22 HS

KFT - Boiling methanol 6 59,32±0,65 0,27 0,36 NS

ResultsLight butter - Linessa

Table 2. Water content in light butter Linessat by different methods

N – Number of replicates, SD – Standard deviation, SEM – Standard error, P – in relation to drying method,NS – without significant difference, VHS – very high significant difference, HS – high significant difference, S – significant difference

ResultsLight butter – Linessa

010203040506070

Oven d

rying

Haloge

n dryi

ng

Microw

ave

Microw

ave 1

20

KFT co

nv.

KFT +

hexa

nol

KFT +

octan

olKFT

+ ch

lorofo

rmKFT

+ tol

uene

Fig.1 Water content in light butter Linessa by different methods

Conclusion

Water content in butter and light butter was determined by several methodsOven drying method was used as reference

Time consumingHigh temperatures may cause a decomposition of the materialNot all of the water in the sample may be detected if the temperature is not high enough

Values obtained by halogen and microwave drying were about one percent lower than those obtained by oven drying.

KF titration, had to be optimised.Chloroform was chosen as suitable solvent for butter. Beside chloroform, hexanol proved to be good solvent for light butters, as well as KF titration in boiling methanol.

Thank you for your attention!

Bernisa Klepo