ultrasonic characterization of foods

John Coupland

[email protected]

@JohnNCouplandFlicker: chotda

Delay line Brass PlateSample

Echo 1

Echo 2

Electrical spike

Time / s

0 5 10 15 20 25 30

Sig

nal /V

-0.2

-0.1

0.0

0.1

0.2

Echo time

Echo amplitude

Electrical spike

Echo 1 Echo 2

Amplitude=f(t)

Magnitude=f(frequency)Phase=f(frequency)

Properties = f(frequency)

FFT

Magnitude Phase

Oscilloscope trace

Lab View

Ultrasonic Properties of a Fluid

Velocity (c) Attenuation ( )

amplitude (A)

distance (x)or time (t)

A = Ao e- xc = d/tc= f

0

0

Ultrasonic Measurements

are Not Interesting

Flicker: jasonr611

FOOD QUALITY

Ultrasonic property

Physical constants

Correlation

E

k2

12c

Velocity

Bulk modulus K+4/3G

(K<<G)

ic

2 f

1/”how many molecules there are per unit volume and how hard is to compress them”

Example: Position and Movement

• “The Lean-Meater can be thought of as an electronic ruler. Ultrasonic pulses sent into the animal are reflected back to the instrument from tissues of interest. The times until these echoes are received are translated into distances in mm. Measurements are non-invasive—no piercing of the skin with the consequent danger of infection. The animals are neither hurt nor irritated.”

http://www.rencocorp.com/lean-meater.htm




Position and Movement

(2)

(1)

(3)

Doppler image adapted from: L. Wang , K. L. McCarthy, M. J. McCarthy, Food Research International 37 (2004) 633–642

Example: Liquid Composition

Flicker: mikeyexists

Blending Operation

Concentration / wt%

0 10 20 30 40 50

Ult

raso

nic

vel

oci

ty /

ms-1

1500

1600

1700

1800

( Sodium chloride, ethanol, glycerol, sucrose, and tomato ketchup)

Composition Measurement by Ultrasonic Velocity

Temperature /°C

0 20 40 60 80 100

Ult

raso

nic

vel

oci

ty /

ms-1

1300

1400

1500

1600

() distilled water, () 20% sucrose solution, () corn oil, and a fine corn oil in water emulsion () =10%, () =50%.

T2T1

J. Benedito *, A. Mulet, G. Clemente, J.V. Garcıa-Perez, Food Research International 37 (2004) 595–601

Olive Oil Processing Waste

Example: Fat Melting

Flicker: dishevld

Temperaturecold hot

100% liquid

100% solidSo

lid F

at C

on

ten

tBrittle solid

Hard solid

Liquid

Spreadable solid

0% 20%

(McClements and Povey, 1987)

Tristearin, tripalmitin or mixtures in paraffin oil, 25°C, 1 MHz

1 1.3 msd

dc

Temp /oC

0 10 20 30 40 50 60

Ve

locity

/ms

-1

1200

1400

1600

1800

2000

2200

Chocolate

[email protected]

Transducers

Crystallization cell for emulsions, fats and oils

Chirp

Example: Particle Sizing

Flicker: bitzi ☂ ion-bogdan dumitrescu

Diameter / m

0.1 1 10

Fre

qu

en

cy /

%

0

5

10

15

20

25

30

35

Emulsion 1

Emulsion 3

Emulsion 5

Fig. 1

Compression Compression Compression

Scattering Mechanisms in Emulsions

log rf0.5

-7 -6 -5 -4 -3 -2 -1 0 1 2 3

c /

ms

-1

1430

1440

1450

1460

Np

0.00

0.01

0.02

0.03

Scattering from an Emulsion

f /MHz

0 1 2 3 4 5 6

c /

ms

-1

1460

1465

1470

1475

1480

Fig. 4a

f /MHz

0 1 2 3 4 5 6

/N

pm

-1

10

20

30

40

50

60

70

80

90

Fig. 4bVelocity Spectra Attenuation Spectra

Dukhin AS, Goetz PJ, Advances in Colloid and Interface Science 92 (1-3): 73-132, 2001

Particle Size Analysis

Concentrated dispersion characterization

Dispersion Technology Inc DT-1200

Flicker: Charlie P Barker

Viscosity

Impedance Measurements

2

12

2

12

)(

)(

ZZ

ZZ

I

IR

i

r

cz

Reflection coefficient is a measure of acoustic dissimilarity

Ultrasonic Viscometry

/ Pa.s

0.01 0.1 1 10 100

Norm

aliz

ed u

ltra

sonic

ref

lect

ance

0.94

0.96

0.98

1.00s20

s60

s200

s600

s2000

Advantages

Flicker: monkeyc.net

Disadvantages

Flicker: Or Hiltch

John Coupland

[email protected]

@JohnNCoupland