Characterization of diverse rice accessions for protein content and its correlation

with starch properties

Maxwell Darko Asante, PhDCSIR-Crops Research Institute

Ghanamdasante@gmail.com

Outline• Introduction

• Materials and Methods

• Results and Discussion

• Summaries and Conclusions22

Introduction

33

Source: FAO,2010

•Average rice production growth rate=3.18% •Average rice consumption growth rate= 4.52%Widening rice supply gap in SSA Rice imports=10.7 million MT (FAO, 2012)

Average paddy yield (tons/ha) •West Africa: 1.62•Central Africa: 0.96•Eastern Africa: 2.20•Southern Africa: 0.91•SSA: 1.51

Rice self-sufficiency status in AfricaRice is the fastest growing food source in Africa

4

Rice in Ghana• Per capita

consumption of rice has increased sharply the last two decades

• But 60-70% of rice consumed (about 1 million MT of milled rice per annum) is imported

• About US$300 million is spent annually on rice imports

Source: MOFA

55

1980 1985 1990 1995 2000 2005 2010 20150

5

10

15

20

25

30

35

40

45

50

Per capita consumption in Ghana

YearRi

ce c

onsu

mpti

on (K

g/pe

rson

/yea

r)

Reasons for Ghana’s high dependence on rice imports

• Low levels of investment in:

– Research

– Production

– Marketing

• This has resulted in:

– Low production levels

– Poor grain quality6

The rice grain is basically made of starch:

• Starch (~94%)

• Protein (~5%)

• Lipids (~1%)

Source: IRRI

Rice grain quality

77

However, variation in the amount of protein in differentrice varieties has been reported

Importance of having rice with higher protein levels

• Rice is the main staple for most poor and malnourished families in Asia and sub-Saharan Africa

• The nutrition of rice consumers in poor countries can be improved by eating rice with higher protein content

• However, high protein content in rice may affect cooking and eating quality which is mainly determined by starch physicochemical properties

88

Objectives • To determine the protein content of a

diverse set of rice accessions

• To determine the correlation between protein content and starch properties including apparent amylose content (AAC), alkaline spreading value (ASV) and paste viscosity properties (RVA) in a diverse set of rice accessions

99

Materials & Methods

1010

Plant Materials

• A total of 88 rice genotypes were used for the study – 65 rice accessions (breeding germplasm

from Ghana referred to African genotypes in this report)

– 23 U.S. cultivars (obtained from the USA)

1111

Determination of protein content

• Protein content was determined by a nitrogen gas analyzer (Leco FP-2000)

• Total crude protein was calculated from the nitrogen content of the processed grain using the formula percentage nitrogen × 5.95 = percentage protein

1212

13

Auto Analyzer 3 machine was used to measure amylose content

RVA was used to measure paste viscosity properties

RESULTS

14

15

Protein Content of African Rice Genotypes

0

2

4

6

8

10

12

14

16

Prot

ein co

nten

t (%)

16

Protein Content of USA Rice Genotypes

0

2

4

6

8

10

12Ea

rlJu

pite

rJa

zzm

anCo

codr

ieCh

enie

reRe

xmon

tD

ellr

ose

Fran

cis

Sier

raTr

enas

seD

elta

belle

Pres

idio

Sabi

neW

ells

Hid

algo

Jasm

ine

85D

ixie

belle

Bow

man

Tesa

nai

Nec

hes

Rond

o21

72A

rbor

io

Prot

ein

Cont

ent (

%)

Correlation amongst starch properties and protein content

17

Traits AAC ASV PV HPV CPV BD SB CS Stability SB ratio

ASV 0.01

PV -0.55*** 0.21

HPV -0.16 0.31** 0.76***

CPV 0.27* 0.29** 0.46*** 0.88***

BD -0.68*** 0.02 0.76*** 0.16 -0.18

SB 0.74*** 0.10 -0.45*** 0.19 0.59*** -0.87***

CS 0.59*** 0.19 0.01 0.50*** 0.86*** -0.49*** 0.86***

Stability 0.41*** 0.21 -0.14 0.51*** 0.69*** -0.74*** 0.83*** 0.70***

SB ratio 0.68*** -0.15 -0.82*** -0.65*** -0.22* -0.60*** 0.53*** 0.30* 0.03

Ptime 0.21 0.25 0.10 0.36*** 0.45*** -0.20 0.36*** 0.42*** 0.39*** 0.00

Protein 0.31** -0.12 -0.52*** -0.23* 0.00 -0.57*** 0.47*** 0.24* 0.36*** 0.45***

Summaries

• Protein content (PC) of African and U.S. rice genotypes were 6.2—13.9% and 5.5—11.3% respectively

• There was positive correlation between PC and, AAC and setback viscosity

• Correlation between PC and breakdown viscosity was negative

18

Conclusions• The results indicate that rice with high

protein is likely to have higher AAC and SBV, and lower BDV implying poorer cooking quality

• However, a local African variety with the highest protein content of 13.9% also had an intermediate AAC of 21.1% making it nutritious and suitable for eating by most rice consumers

19

Acknowledgement

USDA CollaboratorsCRI Team