RVA starch pasting profiles

and Promatest protein

solubilities of grain sorghums

Ha H Truong, Ali Khoddami, Thomas H. Roberts, Sonia Yun Liu and Peter H Selle

Weighbridge assessments of feed grain quality

Maize

Wheat

White sorghum

Red sorghum

White corn

RVA starch pasting profiles

Promatest protein solubility

Texture (Symes PSI)

NIR amino acids

AusScan

4.2g sorghum + 23.8 g deionised H2O

Slurry held at 50°C for 1 minute

heated 95°C/2.5 minutes Peak + Holding cP

cooled 50°C/2 minutes Final cP

Rapid-Visco Analysis (RVA) starch pasting profiles

Time (seconds) 13 minutes

sorghum

wheat

Sorghum and wheat RVA starch pasting profiles

Time (seconds) 13 minutes

sorghum

wheat

Sorghum and wheat RVA starch pasting profiles

Peak

Final

Holding

Breakdown: Peak – Holding

Setback: Final - Holding

RVA starch pasting profiles

of the six Liverpool Plains sorghums

Peak (cP): Min 2455, Mean 4759, Max 6857

RVA profiles of 8 sorghums evaluated in RIRDC sorghum starch project

Peak (cP): Min 2392, Mean 4702, Max 9511

Item r Significance

Peak- AME

Peak-ME:GE

Peak-AMEn

Holding-FCR

Holding-Starch PJ

Holding-Starch:Prot. dis. PJ

Final-FCR

Final-N retention

Final-Starch dig. PJ

Final-Protein dig. PJ

Final-Starch:Prot. dis PJ

r = 0.789

r = 0.800

r = 0.835

r = -0.821

r = -0.906

r = -0.754

r = -0.832

r = 0.881

r = -0.933

r = 0.803

r = -0.930

P = 0.062

P = 0.056

P = 0.039

P = 0.045

P = 0.013

P = 0.083

P = 0.040

P = 0.021

P = 0.007

P = 0.054

P = 0.007

Cherry-picked correlations between Peak, Holding and Final

RVA viscosities and bird performance parameters

from RIRDC sorghum starch study #4

RVA starch pasting profiles

of the six sorghums –

Starch digestibility

RVA viscosity is correlated

to AME

R² = 0.3684

11.4

11.6

11.8

12

12.2

12.4

12.6

12.8

2450 2650 2850 3050 3250 3450 3650

AM

E (

MJ

/kg

DM

)

Holding RVA viscosity of sorghum (cP)

Sorghums:

MP

JM

HP

Tiger

HFQ

Final RVA viscosity is correlated to FCR

(r = -0.832; P < 0.05)

Hence RVA starch pasting

properties may be indicative

of broiler performance on

sorghum-based diets

Pros

-Cheap and quick measurement

-A more in depth understanding of starch

characteristics than amylose:amylopectin ratios

Cons

-May only be indicative in sorghum?

-Unknown: the effects of other feed ingredients

on sorghum starch

Na metabisulphite had a profound effect on RVA starch pasting

properties presumably as the result of oxidative-reductive

depolymerisation (ORD) of starch polysaccharides

Effect of Na metabisulphite [0 and 5.25 g/kg] on RVA

viscosities of starch extracted from sorghum-based diets

Peak viscosity 1444 1065 cP -26.2%

Final viscosity 1035 441 cP -57.4%

Final

Final

Peak

Peak

With 5.25 g/kg SMBS

Effect of Na metabisulphite [0 to 5.25 g/kg] on final

RVA viscosities of starch extracted

from sorghum-based diets

SMBS reduces RVA starch pasting properites while increases protein solubility – better access

of amylase to starch?

The protein solubilities of the white and red sorghums

per se and the six experimental diets were determined.

The Promatest method was used, which compares the

solubility of extracted protein with albumin as the 100%

soluble standard as described by Odjo et al. (2012).

Odjo S, Malumba P, Dossou J, Janas S, Bera F (2012)

Influence of drying and hydrothermal treatment of corn on the denaturation of salt-

soluble proteins and color parameters.

Journal of Food Engineering 109, 561–570.

Promatest protein solubility A ‘weighbridge assessment’ of grain sorghum in

chooks?

The Promatest method compares the solubility of extracted protein with

albumin as the 100% soluble standard (Odjo et al. 2012).

Promatest protein solubility Protein solubility of six red sorghums ex

Liverpool Plains, 2009 harvest

R² = 0.2937

40

41

42

43

44

45

46

47

48

49

50

40 45 50 55 60

Pro

ma

tes

t p

rote

in s

olu

bilit

y

(%)

Kafirin (g/kg)

Kafirin concentrations in sorghum –

negatively correlated with protein solubility

R² = 0.7641

14.75

14.85

14.95

15.05

15.15

15.25

15.35

15.45

15.55

15.65

40 42 44 46 48 50

AM

E (

MJ

/kg

)

Promatest protein solubility (%)

Promatest protein solubility is

correlated with AME, AMEn and

ME:GE ratios

R² = 0.9514

0.875

0.885

0.895

0.905

0.915

0.925

40 45 50

ME

:GE

ra

tio

Promatest protein solubility (%)

R² = 0.6844

14.25

14.45

14.65

14.85

15.05

40 42 44 46 48 50

AM

En

(M

J/k

g)

Promatest protein solubility (%)

SMBS increases Promatest protein

solubility

Responses from 34.8 to > 60%

R² = 0.4577

2250

2750

3250

3750

4250

4750

5250

5750

6250

6750

40 45 50 55 60

Pe

ak

RV

A v

isc

osit

y (

cP

)

Kafirin (g/kg)

R² = 0.2937

40

41

42

43

44

45

46

47

48

49

50

40 45 50 55 60

Pro

ma

tes

t p

rote

in s

olu

bil

ity (

%)

Kafirin (g/kg)

Kafirin may depress

peak RVA viscosity

and

Promatest protein

solubility

of grain sorghums

P = 0.140

P = 0.267

RVA starch pasting profiles, in

combination with Promatest

protein solubilities may

determine feed grain quality

(including digestive dynamics)

in broiler chickens.

Further R&D is justified but,

fortunately, will be completed

Conclusion