MAP Milling training material - Toiduliittoiduliit.ee/Upload/User/File/ettekanded/IGV training material.pdf · MAP Milling Project ... mycotoxins, pesticides and acrylamide in grain

Project funded by the European Commission under the research and technological development

programme 'Integrating and strengthening the ERA' (2002-2006)

MAP Milling Project - Measure and control of

mycotoxins, pesticides and acrylamide in grain

milling sector

IGV Institute for Cereal Processing Ltd.

Arthur-Scheunert-Allee 40-41

14558 Nuthetal OT Bergholz-Rehbrücke

Germany

department

analytics/quality management

technical part

Dr. Monika Springer, Ute Meister

department

technology transfer

financial part

Ines Gromes

Training

material

about

* Mycotoxins

* Acrylamide



MAP Milling - Part mycotoxins

Assessment of rapid

methods for mycotoxins



Mycotoxins

Maximum levels for the Fusarium toxins DON and zearalenone

100 (maize*): 200)

75

50

20

Unprocessed cereals, maize flours/germs

Cereal flour, bran, germ (without maize)

Bread, pastries, biscuits, cereal snacks,

breakfast cereals

Processed cereal-based baby food

zearalenone

1250 (durum, oats, maize*): 1750)

750

500

750

200

Unprocessed cereals

Cereal flour, bran, germ

Bread, pastries, biscuits, cereal snacks,

breakfast cereals

Pasta (dry)


DON

Maximum level (µg/kg)ProductMycotoxin

Source: commission regulation (EC) No 1881/2006 of 19 December 2006; *) max. levels for maize / processed maize products: from 1.7.2007



Mycotoxins

Maximum levels for other mycotoxins in cereals / cereal products

2000

1000

400

200

Unprocessed maize*)

Maize flour, germ, oil *)

Processed maize products *)

Processed cereal-based baby food *)

Fumonisin

B1+B2

5

3

0.5

Unprocessed cereals

Cereal products


OTA

2 / 4

5 / 10

0.1 / -

Cereals and cereal products

Maize for sorting or other treatment


Aflatoxin B1 /

Aflatoxins (sum)

Max. level (µg/kg)ProductMycotoxin

Source: commission regulation (EC) No 1881/2006 of 19 December 2006;*) max. levels for fumonisins in maize / processed maize products: from 1.10.2007



Mycotoxins

Maximum levels for other mycotoxins in feed

0.005 - 0.02feedingstuffsAflatoxin B1

8 (maize by-products: 12)

0.9 - 5


Other complementary / complete feedingstuffsDON*)

2 (maize by-products: 3)

0.1 - 0.5


Other complementary / complete feedingstuffsZearalenone*)

60

5 - 50

Maize and maize products

Other complementary / complete feedingstuffs

Fumonisin*)

B1+B2

0.25

0.05 - 0.1


Other complementary / complete feedingstuffsOTA*)

Max. level (mg/kg)ProductMycotoxin

*) guidance values



Mycotoxins

Accuracy and precision of analytical methods for mycotoxins

Performance criteria according to commission regulation (EC) No 40172006

< 20

< 20

RSDr %

< 40

< 40

RSDR %

60 to 110> 100 - < 500

70 to 120> 500

Recovery %Level µg/kg

for zearalenone:

< 25

< 40

RSDr %

< 40

< 50

RSDR %

60 to 120< 50

70 to 120> 50

Recovery %Level µg/kg

for DON:



Mycotoxins

Results of DON ELISA test – comparison with HPLC

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33

sample number

DO

Nc

on

ten

t(µ

g/k

g)

DON µg/kg HPLC DON µg/kg ELISA

DON contents of wheat samples,

analyzed with HPLC and ELISA

(NEOGEN Veratox® DON test )

Anthos reader

Result:DON contents, analyzed by ELISA were with one exclusion lower than

the values measured by HPLC (HPLC values by 4-33 % higher than ELISA)

- DON limit raw cereals



Mycotoxins

Results of DON ELISA test – correlation with HPLC

correlation coefficients:

- 0.984 for all values

- 0.991 for the values

up to 2000 µg/kg

y = 0,7345x + 116,73

R2 = 0,9687

0

500

1000

1500

2000

2500

3000

3500

4000

0 1000 2000 3000 4000 5000

DON HPLC (µg/kg)

DO

NE

LIS

A(µ

/kg

)

Correlation between HPLC and ELISA was very good



Mycotoxins

Results of DON strip test of r-biopharm – comparison with HPLC

RIDA® QUICK DON strip test of r-biopharm:

- Deviations from a limit value of 1000 or 2000 µg/kg are

checkable (depending on dilution and sample weight )

- Interpretation of the measuring results is difficult because

fading of colour intensity of a visible red-brown colour

band on the strip has to be evaluated visually

- Evaluation is not a simple Yes/No decision because the

changes from maximum to weak colour intensity are

flowing

- In case of DON contents from 500 µg/kg onwards the

colour intensity of the bands was so low that measuring

results were evaluated as positive (i.e. > 1000 µg/kg)



Mycotoxins

Results of DON strip test of r-biopharm – comparison with HPLC

Comparison of RIDA® QUICK DON strip test

(r-biopharm) with HPLC

Result:Of the total of 35 wheat samples, 9 samples had an incorrectly positive evaluation

-> Correlation between HPLC and RIDA® QUICK DON strip test was low

0

1000

2000

3000

4000

5000

6000

7000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35

sample number

DO

N(H

PL

C)

µg

/kg

0

1

2

resu

lts

of

dip

sti

ck

test

DON µg/kg HPLC result of dipsticks




Mycotoxins

DON strip test of neogen – comparison with HPLC

REVEAL®DON strip test of neogen

0 = not detectable DON content < 0.5 mg/kg

0.5 = positive result DON content between 0.5 – 1 mg/kg

1.0 = positive result DON content between 1 – 2 mg/kg

2.0 = positive result DON content > 2 mg/kg

- in this strip test , too, differently coloured lines are obtained,

but the intensity of the lines can be measured by AccuScan reader

- Algorithms programmed into the AccuScan reader convert the

measured line density into a semi-quantitative result:

AccuScan reader



Mycotoxins

Results of DON strip test of neogen – comparison with HPLC

Comparison of neogen REVEAL®DON strip test with HPLC

0

200

400

600

800

1000

1 2 3 4 5 6 7 8 9 10 11 12

wheat samples w ith DON contents >500-1000 µg/kg

DO

N(H

PL

C)

µg

/kg

0

0,5

1

res

ult

so

fd

ips

tic

kte

st

DON µg/kg HPLC results of dip sticks

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

1 3 5 7 9 11 13 15 17 19 21 23 25

wheat samples w ith DON contents >1000-2000 and >2000

µg/kg

DO

N(H

PL

C)

µg

/kg

0

0,5

1

1,5

2

res

ult

so

fd

ips

tic

kte

st

DON µg/kg HPLC results of dip sticks


- DON limit cereal flours

- Of 56 measured samples, only 2 of 12 samples in the range

of concentrations >500 - <1000 had a too low/too high

semiquantitative result (but both samples had DON

contents in a borderland of decision: 520 respectively 909

µg/kg)

- In the range of DON-concentrations >1000 µg/kg

3 samples had a lower result than expected (2 samples had

DON contents widely above the legal limit of raw grain and

1 sample had a DON content of just above 1000 µg/kg )

Result:good correlation between HPLC and

Reveal DON strip test



Mycotoxins

Principle of Fluorescence polarisation immunoassay (FPI)

Competition of mycotoxin (red Ag)

with fluorescein labelled mycotoxin

(green Ag) for binding to antibody

(Ab)

At illumination with polarized light:

- negative samples with bound fluores-

cein labelled mycotoxin (green Ag)

show a polarized fluorescence

emission (= 100 %)

- samples with mycotoxin content show

reduced or no polarized fluorescence

emission (= 100 % - x)Source: http://www.lfl.bayern.de/labor_aktuell/artikel/12074/linkurl_0_0_0_1.pdf



Mycotoxins

Fluorescence polarisation immunoassay (FPI) for zearalenone

Prototype of the FP 470 of AOKIN AG

Calibration curve of zearalenone



Mycotoxins

Results of FPI for ZEA – comparison with HPLC

AOKIN FP 470

0

50

100

150

200

250

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

sample number

zeara

len

on

co

nte

nt

(µg

/kg

)

Zearalenon (µg/kg) HPLC Zearalenon (µg/kg) AOKIN FP

Zearalenone contents of wheat

samples, analyzed with HPLC and

fluorescence polarization

Result:ZEA contents, analyzed by HPLC, were confirmed by FPI with deviations of + 40 %

(positive deviations are due to the fact that zearalenone derivatives are co-detected by

antibody-based FP)

- ZEA limit raw cereals



Mycotoxins

Results of FPI for zearalenone – correlation with HPLC

y = 0,9112x + 6,3255

R2 = 0,9135

0

50

100

150

200

250

0 50 100 150 200

Zearalenon HPLC (µg/kg)

Ze

ara

len

on

FP

AO

KIN

(µg

/kg

)

Correlation between HPLC and fluorescence polarization was adequate

to a rapid method (correlation coefficient: 0.956)

Result:

Correlation between HPLC

and fluorescence polarization



Mycotoxins

Fourier transform infrared spectroscopy (FTIR )

FTIR measurements were performed with a FTIR spectrometer 8400S from Shimadzu,

fitted with a single reflection diamond ATR element (Golden Gate)



Mycotoxins


Mid-infrared spectrum of wheat

8001000120014001600180020002400280032003600400044001/cm

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0,45

0,5

AbsThe rectangle marks the

range chosen for data

analysis according to Kos

et al. (2003) Anal Chem

75: 1211-1217

-> they observed the greatest

changes caused by mould in

the spectral range of 1800-800

cm-1 (bands of carbohydrates,

proteins, lipids).



Mycotoxins


Mid-infrared spectrum of wheat - unsieved sample

-> 10 measurements: 10 relatively different spectra

7501000125015001750200025003000350040004500

1/cm

0,075

0,15

0,225

0,3

0,375

0,45

Abs



Mycotoxins


Mid-infrared spectrum of wheat - sieved sample (112-250 µm)

-> better agreement between 10 measured spectra

7501000125015001750200025003000350040004500

1/cm

0,075

0,15

0,225

0,3

0,375

0,45

Abs



Mycotoxins


Mid-infrared spectrum of wheat - sieved sample (< 112 µm )

-> good agreement between 10 measured spectra

For calibration,

validation and

measurement of

unknown samples

only the sieving

fractions <112 µm

of the ground

samples were used

7501000125015001750200025003000350040004500

1/cm

0,1

0,2

0,3

0,4

0,5

Abs



Mycotoxins

DON: Correlation of HPLC / FTIR

Calibration of FTIR 8400S

with 14 wheat samples(DON contents: 60-2590 µg/kg)

Calibration

y = 0,9802x + 24,821

R2 = 0,9802

0

500

1000

1500

2000

2500

3000

0 500 1000 1500 2000 2500 3000

Actual

Pre

dic

ted

A calibration with a good correlation was achieved (correlation coefficient: 0.9901)

Result:



Mycotoxins

DON analysis possible with FTIR?

Full cross-validation (samples)

y = 0,3045x + 820,27

R2

= 0,24320

500

1000

1500

2000

2500

3000

0 500 1000 1500 2000 2500 3000

Actual

Pre

dic

ted

Full cross-validation

with 14 wheat samples(DON contents: 60-2590 µg/kg)

Correlation significantly worsened at full cross-validation (correlation coefficient

only 0.4932)

Correct predictions of the DON content of unknown samples were not possible

Obviously there is no direct connection between changes of the components of the

grain kernels (carbohydrates/proteins/fats) by moulding and the DON content (other

fungi which do not produce DON could have caused the measured changes)

Result:



Mycotoxins

Correlation DON HPLC – Fusarium damaged kernels ?

healthy kernels, normal size

white to reddish colour, stronglyshrunken fusarium damagedkernels

kernels of normal appearancewith red tip (seldom)

dented kernels, normal size,mycel in the ventral fold

Source: http://www.lfl.bayern.de/labor_aktuell/artikel/12074/linkurl_0_0_0_1.pdf

Due to frequent

request of farmers,

grain-chandlers

and millers, the

suitability of the

visual assessment

(analysis of

Fusarium damaged

kernels) also was

compared with

HPLC.



Mycotoxins

Correlation DON HPLC / Fusarium damaged kernels ?

Comparison of the

DON contents of all

60 wheat samples

(0.5 - 34 mg/kg)

with the analysis of

Fusarium damaged

kernels

0,0

5,0

10,0

15,0

20,0

25,0

30,0

35,0

sample number

fore

ign

matt

er

(%)

0,0

5,0

10,0

15,0

20,0

25,0

30,0

35,0

DO

Nc

on

ten

tH

PL

C(m

g/k

g)

red co lo ured kerne ls (%) r = -0,191

s hrunken kerne ls , white co a t (%) r = 0,897

Fus arium damaged kerne ls , to ta l (%) r = 0,836

DON co ntent HP LC (mg/kg)

Result:Correlation between HPLC and

- white, shrunken kernels with whitish coat

- Fusarium damaged kernels (total)

No correlation between HPLC and

- red coloured kernels



Mycotoxins


Correlation at high DON contents (4 – 34 mg/kg):

0,0

2,0

4,0

6,0

8,0

10,0

12,0

14,0

16,0

18,0

20,0

17 5 29 41 53 18 6 30 54 42 16 4 28 40 52

sample number (wheat cultivar I)

%fo

reig

nm

att

er

0,0

2,0

4,0

6,0

8,0

10,0

12,0

14,0

16,0

18,0

20,0

DO

Nm

g/k

g(H

PL

C)

red co lo ured kernels (%) r = 0,104

s hrunken kernels , white co a t (%) r = 0,933

Fus arium damaged kernels , to tal (%) r = 0,909


0,0

5,0

10,0

15,0

20,0

25,0

8 20 44 32 56 9 33 21 57 45 19 7 31 43 55

sample number (wheat cultivar II)

%fo

reig

nm

att

er

0,0

5,0

10,0

15,0

20,0

25,0

DO

Nm

g/k

g(H

PL

C)


red co lo ured ke rne ls (%) r = -0,087

s hrunken ke rne ls , white co at (%) r = 0,842

Fus a rium damaged ke rne ls , to tal (%) r = 0,695

good correlation

in wheat samples

of cultivar I

lower correlation in wheat samples of cultivar II and III :

0,0

5,0

10,0

15,0

20,0

25,0

30,0

35,0

14 2 50 38 26 3 51 15 27 13 39 1 25 49 37

sample number (wheat cultivar III)

%fo

reig

nM

att

er

0,0

5,0

10,0

15,0

20,0

25,0

30,0

35,0

DO

Nm

g/k

g(H

PL

C)

red co lo ured ce rne ls (%) r = -0,471

s hrunken kernels , white co a t (%) r = 0,824

Fus a rium damaged ke rnels , to tal (%) r = 0,691




Mycotoxins


No or very low correlation at DON concentration range of interest to the

milling industry (0.5 – 3 mg/kg) !

Visual assessment – althogh frequently used in practice – is not suited as

rapid method !

0,0

1,0

2,0

3,0

4,0

5,0

6,0

7,0

8,0

9,0

10,0

11 47 23 35 59 24 12 48 60 36 22 10 34 58 46

sample number

%fo

reig

nm

att

er

0,0

1,0

2,0

3,0

4,0

5,0

6,0

7,0

8,0

9,0

10,0

DO

Nm

g/k

g(H

PL

C)

red co lo ured kerne ls (%) r = -0,012

s hrunken kernels , white co at (%) r = 0,521

Fus arium damaged kernels , to tal (%) r = 0,216


Comparison of the

DON contents of

wheat samples with

low DON content

(0.5 - 3 mg/kg) with

the analysis of

Fusarium damaged

kernels

Result:



Mycotoxins

Assessment of methods for mycotoxins (DON, zearalenone)

> 40 €> 50 T€high (chemist)> 1 dayimpossibler < 0,800

30 - 40 €>30 - 50 T€< 4 hr > 0,802

20 - 30 €>10 - 30 T€< 2 hr > 0,854

10 - 20 €>2 - 10 T€< 1 hr > 0,906

< 10 €< 2 T€< 30 minr > 0,958

00low< 20 minpossibler = 110

Scale:

3210106600Fus. damag. kernels

15-251024(0*/ 9)00FTIR

41 ?(4-6) ?**(6)?**6888Fluor. polarization

4788101074Dipstick neogen

4081081040Dipstick r-biopharm

40466888ELISA

reference(2)0(0)(2)(10)(10)HPLC

SummaryMaterial costs

per sample

Invest-

ment

Required expe-

rience /qualific.

RapidityControl of

legal limit

Exact

quantific.

Method

* time-consuming calibration with HPLC required for rapid measurement ** costs unknown yet



Mycotoxins

Assessment of methods for mycotoxins - conclusion

Conclusion:

The rapid methods were evaluated with respect to the possibilities to control the

legal limits for mycotoxins and also to their rapidity, the required experience /

personnel qualification and the costs for investment / analysis.

Bearing in mind these criteria the Neogen Reveal® DON strip was evaluated

best. The strip test can be used for the detection of a transgression or falling-

below a limit value.

Exact quantification of mycotoxin contents according to this test is not possible.

For this purpose only HPLC or another chromatographic method can be used.



MAP Milling - Part acrylamide

Study about acrylamide

formation and minimization



Acrylamide

Signal values for acrylamide

signal value (µg/kg)

11/01/0721/10/0517/11/0426/11/0331/01/0317/09/00

productcereals

extruded flat bread,

crisp bread

gingerbread

diabetic pastries

almond biscuit

short crust pastries

cookies for children, rusk

breakfast cereals

(cornflakes)

610

1000

n.c.

710

660

n.c.

260

610

1000

n.c.

1000

800

n.c.

260

610

1000

1000

710

575

360

200

590

1000

545

560

300

245

180

416560

10001000

197360wheat

300575

5451000

496610rye

180200maize



Acrylamide

Formation of acrylamide in food

For the formation of acrylamide several pathways have been proposed:

First pathway discussed is the Strecker pathway about aminopropionamide as intermediate

Beside Strecker pathway with aminopropionamide other ways have been found:- a biochemical way by decarboxylation of asparagines

- a thermal way (Amadori pathway) with 3-amino-propionamide

- another thermal way (Strecker pathway) with 3-hydroxy-propionamide

In all the ways, free asparagine is the pre-metabolite



Acrylamide

Formation of acrylamide in food

Strecker pathway with aminopropionamide as intermediate:

- Pathway is characterized by a series of reactions between amino acids, primary free

asparagine, and a reducing sugar (fructose or glucose)

- Reactions are part of the Maillard reaction, which also causes the browning of food

and development of taste during baking

- Heat (>140 °C) and dryness are important reaction conditions

- The high potential of aminopropionamide for acrylamide formation results from the

easy thermal elimination of NH3

- If asparagine is replaced by other amino acids (cysteine, threonine, methionine)

the acrylamide production is quite lower

- Also substitution of glucose, fructose by saccharose or lactose showed a lower

potential of acrylamide formation



Acrylamide

Aim of the project

Known, quite effective technological variations in minimization of acrylamide are

- increasing product moisture

- decreasing baking temperature and baking time

The aim of the project was:

- the investigation of the influences in raw materials to get knowledge about the

content of free asparagine

- to show links between free asparagine in cereals and acrylamide in baking or

extrusion products



Acrylamide

Link between free asparagine and acrylamide

0

200

400

600

800

1000

1200

1400

1. passage 2. passage whole grain bran

acry

lam

ide

(µg

/kg

dm

)

0

50

100

150

200

250

300

350

400

450

asparagine (mg/kg dm)

free asparagine

(mg/kg dm.)

acrylamide µg/kg dm

0

100

200

300

400

500

600

700

800

rye Fernando 04 rye Fernando 05 bio rye Hacada

As

pa

rag

ine

infl

ou

r(m

g/k

g)

0

100

200

300

400

500

600

Ac

ryla

mid

ein

cri

sp

bre

ad

(µg

/kg

)

Asparagine (mg/kg)

Acrylamide (µg/kg)

in industrially produced crisp bread

Study of the link between free asparagine and acrylamide formation:

in a model dough

It has been shown that content of acrylamide is increasing with increasing

content of free asparagine in the model dough as well as in the crisp bread



Acrylamide

Distribution of asparagine in different grain layers

0

200

400

600

800

1000

1200

1400

1st passage 2nd passage whole grain bran

Asp

ara

gin

e(m

g/k

g)

0

0,5

1

1,5

2

2,5

3

3,5

4

To

tal

ash

(g/1

00g

)

Asparagine (mg/kg)

total ash (g/100g)

- The different types of flour are

obtained by including different

grain layers during milling

process

- They are characterised by

different mineral contents.

It has been shown that the content of free asparagine is increasing with

increasing ash content



Acrylamide

Distribution of asparagine in different kinds of grain

asparagine (mg/kg)

0,0

100,0

200,0

300,0

400,0

500,0

600,0

700,0

800,0

900,0

1.000,0

ryeoats

wheat

durum

rice

There are wide differences in content of free asparagine between the different cereals

There is an increase from the lowest content in rice and maize to the highest content

in rye

maize



Acrylamide

Lowest asparagine content in rice

370 - 489wheat

146 - 467hard wheat

47 - 95maize

459 - 880rye

504oat

13 - 20rice

mg/kg free asparagineCereal

The different kinds of grains are used for specific products:

One example in this direction is the rice tin bread

produced by PEMA Wholemeal Specialties

Heinrich-Leupoldt KG, Weißenstadt, Germany:

For extrusion products it is possible to use types of grains with low

content of asparagine, like rice or maize. But also for baked goods

cereals with a low content of asparagine should be considered as

possible ingredient.



Acrylamide

Distribution of asparagine in different rye varieties

Content of free asparagines in rye varieties

0

100

200

300

400

500

600

700

800

900

1000

Born

Born

Born

Born

Nik

ita

Avant

i

Picas

soBar

oC

ilion

fre

ies

As

pa

rag

in(m

g/k

g)

0

100

200

300

400

500

600

700

800

900

1000

Du

rch

sc

hn

itt

fre

ies

As

pa

rag

in(m

g/k

g

free asparagines (mg/kg)

average free asparagines mg/kg

But due to the scattering of the asparagine contents in rye samples of one variety

it is not possible to select rye varieties of low asparagine content.

It was shown that rye has a high

content of free asparagine.

In the survey on the frequency

of acrylamide distribution, crisp

bread made from rye belongs to

the product group with a high

content of acrylamide.

Therefore, efforts were made to

select rye varieties with a low

content of free asparagine.

Fre

easpara

gin

e(m

g/k

g)

Fre

easpara

gin

e,avera

ge

(mg/k

g)



Acrylamide

Influence of additional ingredients on the reduction of acrylamide

The formation of acrylamide proved to depend on pH. Acrylamide formation is

increasing at alkaline conditions.

Reducing the pH value can reduce acrylamide.

Therefore efforts were made to reduce acrylamide by the addition of organic acids.

The high potential in minimizing acrylamide and a minimum sensory influence on

the final product were the criteria for the selection of the kind and concentration of

organic acids.



Acrylamide

Influence of organic acids

0

20

40

60

80

100

120

0,0% 0,5% 1,0% 2,0%

organic acid, conentration (%)

ac

ryla

mid

e(%

),s

tan

da

rd=

10

0% ascorbic acid

citric acid


in a model dough

Both acids were effective to minimize acrylamide in baked products

to 25 % of standard tests without any organic acid addition



Acrylamide


0

50

100

150

200

250

300

350

standard

recepture

ascor. acid

7 p.m.

ascor. acid

9 p.m.

ascor. acid

11 p.m.

ascor. acid

1 a.m.

ascor. acid

3 a.m.

ascor. acid

5 a.m.

acry

lam

ide(µ

g/k

g)

Influence of organic acid in

industrially produced crisp

bread

Signal value Crisp bread

11/01/2007: 496 µg/kg

Crisp bread was produced

according to two different recipes:

- standard recipe without the

addition of ascorbic acid

- recipe with the addition of

1% ascorbic acid

Samples were taken in intervals of

two hours during two production

periods, i.e. for about 12 hours

A reliable minimizing effect of appr. 30 % was achieved by the addition of 1 %

ascorbic acid without any negative effect on the sensory properties

recipe



Acrylamide

Study about acrylamide formation and minimization - Conclusions

Acrylamide can be reduced by

low content of free asparagine in raw material

• content of free asparagine in endosperm lower than in bran

• rice and maize have lower contents than wheat and rye

• Triticum durum has lower content than Triticum aestivum

• variety differences show wide scattering

addition of organic acid (ascorbic acid)

combining several reducing parameters, if possible

Documents

MAP Milling training material - Toiduliittoiduliit.ee/Upload/User/File/ettekanded/IGV training material.pdf · MAP Milling Project ... mycotoxins, pesticides and acrylamide in grain