Table Of ContentSORGHUM BIOCHEMISTRY:
AN INDUSTRIAL PERSPECTIVE
SORGHUM
BIOCHEMISTRY:
AN INDUSTRIAL
PERSPECTIVE
C.V. R
ATNAVATHI
ICAR-IndianInstituteofMilletsResearch,Rajendranagar,Hyderabad,India
J.V. P
ATIL
CollegeofAgriculture,Pune,Maharashtra,India
U.D. C
HAVAN
MahatmaPhuleKrishiVidyapeeth,Rahuri,Maharashtra,India
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Biography
C.V. RATNAVATHI, PhD
Principal Scientist, Plant Biochemistry and Joined
Agricultural Research Service in 1985 and work-
ing on Sorghum since 1989.
Dr. Ratnavathi has a PhD in Biochemistry from
Osmania University, and currently serves as the
Principal Investigator on the NASF project on
sweet sorgum for efficient bioethanol production,
while also leading a research project from the
DBT on the therapeutic properties of sorghum.
She has led several other externally funded
projects like NATP on value addition to sorghum
and was instrumental in establishing a food processing laboratory
under the NAIP Millet Value chain project. She has developed 30 sor-
ghum recipes and 10 semiprocessed products, and has published
numerous journal articles, books, and book chapters. She is recognized
by the CODEX Committee for her research work on aflatoxins in
sorghum. Dr. C.V. Ratnavathi has been awarded the fellowship of the
Andhra PradeshAcademy of Sciences,Guntur.
J.V. PATIL, PhD
Former Director, ICAR-Indian Institute of Millets
Research (IIMR) (Formerly Directorate of
Sorghum Research), Indian Council of
Agricultural Research (ICAR), Hyderabad, India.
He is presently Associate Dean and Principal,
CollegeofAgriculture,Pune,Maharashtra,India.
Dr. Jagannath Vishnu Patil is a leader
in sorghum and pulses research and has devel-
oped improved varieties/hybrids of it. He has
also conceptualized innovative technologies for
ix
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BIOGRAPHY
germplasm conservation and productivity enhancement in crops. He has
been elected a Fellow of the Indian Society of Genetics and Plant
Breeding, Indian Society for Pulses Research and Development, and
National Academy of Agricultural Sciences. He is instrumental for ele-
vating the Directorate of Sorghum Research (DSR) to the Indian Institute
ofMilletResearch(IIMR).
Under the leadership of Dr. J.V. Patil, IIMR has been awarded Centre
of Excellence for value addition and processing of Sorghum. He has
successfully demonstrated the production to consumption value chain
in sorghum.
U.D. CHAVAN, PhD
Professor and Senior Cereal Food Technologist,
Department of Food Science and Technology,
Mahatma Phule Krishi Vidyapeeth, Rahuri,
Ahmednagar, Maharashtra, India.
Dr. Chavan worked as the Senior Research
Assistant in the Department of Biochemistry and
Food Science and Technology at Mahatma Phule
Krishi Vidyapeeth, Rahuri from 1988 to 2000. He
received his Ph.D. degree in Food Science from
Memorial University of Newfoundland, St. John’s,
Canada in 1999. During his PhD, he worked as a
Technician/Research Associate at Atlantic Cool Climate Crop Research
Center and Agriculture and Agri-Food Canada. He has received several
awards and fellowships, including the International Scholar Award for
his PhD work at Memorial University and a Lifetime Achievement
Award for his contribution to postharvest technology. He has written
138 research papers, 140 popular articles, and 42 books in multiple lan-
guages.HehasdoneInternationaltrainingon“GlobalNutrition2002”at
Uppsala University, Uppsala, Sweden in 2002. He has also contributed
in the development of crop varieties in wheat (one) and Sorghum
(eleven). He has been given nine recommendations in the field of Food
Science and Technology. He is handling five National and International
Research Projects on Sorghum. He has guided 25 MSc Students in the
DisciplineofFoodScienceandTechnologyandBiochemistry.Nowheis
working as a Professor in the Department of Food Science and
Technology,aswellasaSeniorCerealFoodTechnologistattheSorghum
Improvement Project and a Foreign Student Advisor at Mahatma Phule
KrishiVidyapeeth,Rahuri,Ahmednagar,Maharashtra,India.
Introduction
Sorghum is an important food and fodder crop of the semiarid tropic
regions (14(cid:1)24(cid:3)N to 70(cid:1)82(cid:3)E). India is the third largest producer
(8.06MT) of sorghum in the world after United States and Nigeria
(FAO Report, 2002), and has the largest area under cultivation for this
crop (8.5Mha) covering the states of Maharashtra, Karnataka, Madhya
Pradesh, Andhra Pradesh, Rajasthan, Gujarat, Tamil Nadu, and Uttar
Pradesh. The rainy season sorghum is often damaged due to grain
mold (GM), so fetches lower prices, but has the greatest potential for its
use in the nonfood and industrial sectors for the production of various
value-added products.
At present, most of the sorghum produced in India is consumed as a
human food in the form of roti or chapatti (unleavened flat bread).
Alternatively, the sweet sorghum with its juicy sweet stalk has
enormous potential as a bioenergy crop. Sorghum is known to have a
highest dry matter productivity rate (50g/m2/day) in a number of
locations across the globe and is reported to surpass the productivity of
sugarcane, another C plant(Somaniet al., 1997).
4
Alternative uses of sorghum encompass the utilization of grain and
sweet stalk in food and nonfood sectors for the production of commer-
cially valued products, such as alcohol (potable and industrial grade),
syrups (natural and high fructose), glucose (liquid and powder), modi-
fied starches, maltodextrins, jaggery, sorbitol, and citric acid (down-
stream products from starch).
Globalanddomesticdemand for animal andpoultry feedarerapidly
rising. Sorghum can act as a prominent source of poultry and animal
feed (Kleih et al., 2000). Similarly, demand for starch and industrial
potable alcohol are continuously increasing. In comparison to other raw
materials, sorghum ensures itself a place as a potential alternative in
this sector. However, sorghum always faces stiff competition from
maize. Apart from this, demand can be created for sorghum in bever-
age industries as malt and adjunct (unmalted cereal component used
for beer preparation). In this book we detail the gradual shift from tra-
ditional uses to the envisaged use of sorghum as value-added food and
nonfood industrial products.
Sweet sorghum (Sorghum bicolor (L.) Moench), a C4 graminaceous
crop which has sugar-rich stalks and which is a water-use-efficient
xi
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INTRODUCTION
crop, has a very good potential as an alternative feedstock for ethanol
production. It is the only crop that provides both grain and stem that
can be used for sugar, alcohol, syrup, jaggery, fodder, fuel, bedding,
roofing, fencing, paper, and chewing. Sweet sorghum juices usually
contain approximately 16(cid:1)18% fermentable sugar, which can be
directly fermented into ethanol by yeast. Technical challenges of using
sweet sorghum for biofuels are a short harvest period for the highest
sugar content and fast sugar degradation during storage. Evaluation
of 160 sweet sorghum genotypes was done for juice extractability.
Sweet sorghum juice mainly contains sucrose, glucose, and fructose.
While sucrose is the predominant sugar during the whole developmen-
tal stages, it constituted only about 50% of the soluble sugar at the boot
stage, glucose and fructose making the remainder. Some studies have
been carried out on the genetic potential of sweet sorghum for higher
green cane yield and juice extractability, whereas some studies have
been purely on the shelf life of the juice and how to preserve the juice
at low cost against bacterial contamination. Studies have also involved
testing the potential of genotypes for superior yields of cane during the
postrainy andsummerseasonstomakethecaneavailableforthemaxi-
mum period in a year. Fermentation studies have also been carried out
using Saccharomyces cerevisiae, the most commonly used species of yeast
in alcohol fermentation. Genotypic variation for ethanol production
from sweet sorghum juice has also been studied. A pilot study was car-
ried out for the evaluation of ethanol production from sweet sorghum
stalk juice.
GM is one of the major biotic constraints of sorghum for feed and
food production. The principal GM fungi in India are Fusarium monili-
forme, Curvularia lunata, Phoma sorghina, Alternaria alternate, Exserohilum,
Gonatobotrytis sp., and Aspergillus spp. GM is the result of a complex of
fungus(cid:1)host interactions, which leads to the complete deterioration of
sorghum grain. Infestation of sorghum grain by storage fungi results in
varying degrees of damage, including (1) discoloration of the kernel,
(2) reduction in kernel germination, (3) heating, (4) mustiness, and (5)
production of mycotoxins. The occurrence of Aspergillus is less com-
pared to Fusarium.
The incidence of GM is moderate to low in Kharif. The disease inten-
sity was medium in Andhra Pradesh, Gujarat, and Tamil Nadu,
whereas it was low in Maharashtra, Karnataka, and Rajasthan. The nat-
ural variability in Aspergillus and Fusarium, the toxicity and potential of
toxin production in sorghum, and the extent of damage to the grain in
detail were given in this report. In sorghum, other toxins detected are
Tricothecenes, Zearalenone, and Fumonisin B and B toxins produced
1 2
by the fungus Fusarium. Some of the fusarial toxins—such as
xiii
INTRODUCTION
zearalenone—exhibit uterotrophic activity. However, Phoma sorghina, a
widely distributed GM fungus, is known to produce tenuazonic acid
and may be responsible for onyalai, a human disorder prevalent in
Africa. Onyalai is diagnosed by hemorrhagic vesicles in the mouth that
appear after the ingestion ofphoma-infected grain.
References
FAO, 2002. HTM Published in 2002 by the Food and Agriculture Organization of the
United Nations, Viale delle Terme di Caracalla Rome, Italy. ,www.fao.org/docrep/
005/y7352e/y7352e00..ISBN92-5-104815-0.
Klieh,U.,BalaRavi,S.,DayakarRao,B.,Yoganand,B.,2000.IndustrialUtilizationofsor-
ghum in India. International Crop Research Institute for Semi-Arid Tropics,
Hyderabad,India.
Somani R.B., A. Almodares, R.B. Pandrangi and A. Sepahi, 1997. Potential of sweet sor-
ghuminIndiaandIranforalcoholandsweetnersproduction.FirstInternationalSweet
sorghumConference,China.
C H A P T E R
1
Sorghum Grain Quality
C.V. Ratnavathi and V.V. Komala
ICAR-IndianInstituteofMilletsResearch,Rajendranagar,Hyderabad,India
O U T L I N E
1.1 Introduction 3
1.1.1 Sorghum Species 3
1.1.2 Grain Quality 6
1.1.3 Sorghum Kernel Structure 6
1.1.4 PhysicalCharacters 9
1.1.5 Biochemical Parameters 10
1.1.6 Protein Estimation 10
1.1.7 Protein Body and Protein Matrix Characteristics of Sorghum 12
1.1.8 Digestibility of Uncooked Sorghum Proteins 12
1.1.9 Determinationof Protein Digestibility 13
1.1.10 Variation inProtein Digestibility 13
1.1.11 Starch 14
1.1.12 Amylose 14
1.1.13 Amylose Estimation 15
1.1.14 Amylopectin 15
1.1.15 Starch Granule Structure 16
1.1.16 Starch Estimation 17
1.1.17 Starch Digestibility of Raw Sorghum Grain 18
1.1.18 Starch Digestibility 18
1.1.19 Starch Digestibility With and WithoutProteasePretreatment 21
1.1.20 Influenceof Protein Predigestion on Starch Digestibility
of Sorghum Genotypes 22
1.1.21 Fat Estimation 23
1.1.22 Tanninsand Phenols of Sorghum Grain 23
SorghumBiochemistry:AnIndustrialPerspective.
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DOI:http://dx.doi.org/10.1016/B978-0-12-803157-5.00001-0 ©2016ElsevierInc.Allrightsreserved.
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1. SORGHUMGRAINQUALITY
1.1.23 Extractionof Polyphenols 25
1.1.24 Prussian Blue Assay 25
1.1.25 PhenolicCompounds and Antioxidant Activity of Sorghum
Grains of Varying Genotypes 25
1.1.26 Phytic Acid Estimation 26
1.1.27 Phytochemical Agents 26
1.1.28 Sorghum Phytochemicalsand Their Impact onHuman Health 27
1.2 Comparison With OtherCereals 28
1.2.1 AlternativeUsesof Sorghum 31
1.2.2 Human Food 32
1.2.3 Animal Feed 33
1.2.4 India 35
1.2.5 China 36
1.2.6 West Africa 36
1.2.7 Eastern and SouthernAfrica 37
1.3 Dough and Roti MakingQuality ofSorghum 38
1.3.1 Dough Quality 38
1.3.2 Roti Quality 42
1.3.3 Traditional Food Products of Sorghum and Their
Commercialization 45
1.3.4 Noodles 55
1.3.5 Low Calorie-Low Fat Cookies 55
1.3.6 Sorghum HealthBenefits 55
References 56
Further Reading 61
Abstract
Sorghum has been an important staple in the semiarid tropics of Africa and Asia
for centuries. Sorghum is also a rich source of various phytochemicals including
tannins, phenolic acids, anthocyanins, phytosterols, and policosanols apart from
proximatecomposition,vitamins,andminerals.Thesephytochemicalshavesignifi-
cant impact on human health. Sorghum is consumed as food in various forms as
roti,tortilla,injera,kisra,tuwo,ugali,bogobe,sankati,ambali,edi,couscous,wowo-
to,noodles,soru,burkutu,busa,ting,andobhsheraindifferentpartsoftheworld.
Since sorghum flour is a gluten-free food, it is a safe alternative for those with
celiac disease. Apart from the traditional products like (bhakri, bhatwadi, papad)
non traditional foods like popped gains, kurdai, biscuits, flakes, upma, idli, dosa,
utappa, chiwada, chakli, ambali, shankarpale, and cakes are also prepared from
sorghum. Alternative uses of sorghum include in nonfood sectors for the produc-
tionofcommerciallyvaluedproducts.
SORGHUMBIOCHEMISTRY:ANINDUSTRIALPERSPECTIVE
