Abstract: Wheat is the Staple crop
of many countries and has a major source of food in the world. The aim of this study
is to provide information about different cereal storage and grading techniques
and discuss the most suitable
technique for storage. Grading is the most important factor involved in the
cereal business it decides the quality of grains. The different parts of the
world have their own grading systems. Grading differentiate between the broken
diseased and infected grain. Price is also decided on the basis of grading.
Cereal grains are stocked to maintain the product from storage to consuming
without any change in the quality. The selection of the most suitable and
economical store has great significance on storage time of cereals under
consideration of climate conditions, types of grain and transportation facility. There are many different
storage methods for the cereals, i.e., bulk storage, storage in underground
pit, storage in bags, storage in sheds and storage in silos. Each system of
Storage has its own merits and demerits. Grains are usually placed as mass pile in straight
stores. Location of storage,
moisture content and ventilation are important factors for cereals stored in
stores. In modern time’s storage methods for cereals has
been advanced with the innovations, as aeration, refrigerated storage, modified
atmospheric storage and hermetic storage systems. Insect and fungus attack on
the stored grains are very common and they are related to storage method.
Wheat is the most
cultivated cereal all over the globe Wheat is one of
the three most significant cereals in the world, collectively with maize and
rice. Roughly 600 million tones are harvested annually with cultivation
extending over a vast geological area, from Scandinavia to Argentina, including
higher areas in the tropics. The most key aspect has been the distinctive
properties of wheat dough that allow it to be processed into a variety of
products Peter R. Shewry, et al, 2002. Wheat is a single-seeded fruit.
4- to 10-mm, long consisting of a germ and endosperm enclosed by an epidermis
and a seed coat. The fruit coat or pericarp (45- to 50-grn thick) surrounds the
seed and adheres closely to the seed coat Lasztity .R, 1999.
methods for grain are essential as a support in trading. Grain is more
efficiently marketed with some form of grading structure in place. A grading
system for grains appreciably influences the effectiveness of other operations,
such as handling, transportation, processing, management, and storage
Hulasare, et al. Grading methods make easy trade in markets by striving to
meet necessities of the consumers and, at the same time, offer drive to
producers to produce desired quality for equitable returns Hulasare, et al.
may be defined as “the segregation of heterogeneous material into a series
of grades reflecting different quality characteristics of significance to the
users” Canada Grains Council, 1982. Factors as strange material
substance. Uniformity within and during transportation, moisture content also
decide the superiority and the price preferably, a grading scheme should take
into account the purchaser penchant (end users) and also ensure fair returns to
the producers Hulasare, et al.
Cereals, such as wheat,
corn, rye, oat, rice, etc., are important source of energy for humans. They method used
for their storage and transportation must preserve their quality. Storage should be of
different types varies with the duration of time ranging from short-term storage on
farm for drying to long-term storage
for planned reserves. That is, storage can be done on farm land or at large
scale commercial facilities Bucklin, et al, 2013. Losses during storage are due to improper storage is
nearly 20% of the whole world production due to increase in population, a massive demand for the cereals worldwide
Said, et al, 2014.
Ramesh 1999 reported
that reduction and significance loss are due to lack of storage infrastructure.
Microbes, pest and enzyme activities, foreign substance, mechanical factors damages and heat
deteriorate the quality of grains during storage, can be avoided by correct
storage process using proper equipment Tüfekçi and S, 2016. Till now, many storage methods have
been used for ages. However the aim of traditional and modern methods is to
protect the grains during storage, to maintain their quality and prevent grain
loses Tüfekçi and S, 2016.
Infestation decrease seed
germination enhance in free
fatty acid levels, moisture, and reduce in pH and
protein contents etc. ensuing in
total quality decrease. Quality losses influence the economic worth of the food grains providing
low prices to farmers
Ipsita et al., 2013.
Major problem for cereal
safety in the climatic region, country, crop, infrastructure and method of
storage leads to post-harvest loss. Secure grain harvest and storage play a vital role
to prevent losses caused mainly by insects e.g. weevils, beetles, moths and
rodents Mishra, et al, 2012.
Prior to storage of
grains, there are many safety parameters from damages, harvesting of crops on time of ripening, drying
of crops on field or farm, storage of new and old crops separately, cleaning of crops from unwanted substances, cautious selection of
storage place, storage arrangement
and fumigation of empty store Hatice Pekmez, 2016.
During storage phase, appropriate
ventilation of grains, regular checking of grain store, cleaning and fumigation of stored
grains have to to be carried out, because these necessities have large significance
on the secure and controlled
storage Mishra, et al, 2012. The store selected properly must satisfy the grain to be kept
dry, maintain at a consistent temperature and protected from insect, rodents and birds Mrema, et al, 2011.
growth in cereals is normally prevented by drying; but, drying procedures are expensive,
particularly in a temperate climate Wisniewski, et al, 1990. The most general
spoilage fungi on cereals are xerophilic Eurotium and Penicillium and
Aspergillus type Lacey, J., and N. Magan. 1991. Penicillium roqueforti is an
particularly important in airtight storage because it produces a number of
mycotoxins,e.g., cangrowatlow and roquefortinC(6) partial vapour pressures of
oxygen at low temperatures Lacey, J.,
and N. Magan. 1991
Dormancy, respiration and viability (germination)
rate of Cereal grain is changed during storage Wrigley et al
Mycotxin formation can be resulted due to the attack of microbes such as when delayed in drying during the
rainy season, and during the parboiling procedure
Vasanthi and Bhat 1990
containers are mainly significant in tropical and semi-tropical regions with
their high temperatures and high humidity. Insects multiply best at 30°C, as
well as at humidity levels above 65% and molds grow exponentially above the
critical moisture level VIHers et al 2006.
These biological agents
, insect and mite pollution, &, discoloration, loss of flavour, and
existence of dangerous mycotoxins cause direct losses in grain
Navarro, 2012. Insects can also favor situation for fungal growth and are one
of the main vectors of their dispersal. Harvest, grain is constantly at danger
of insect infestation, and because of that the grain storage industries methodically
use chemical control methods. Shlomo Navarro, 2012.
Most Plant fruits contain one or more than one
seeds, at the time of ripeness, which can be easily alienated
from rest of fruit. For Germineae family this
is different: fruit wall (pericarp) and seed coat are combined.
The seed and fruit cannot be divided. This is quality for all grasses, containing all
cereals, so given the botanical name of caryopsis
Zuzana Šramkováa, et al, 2009. Wheat grains are usually oval shaped, though many
wheat’s have grains that vary from nearly spherical to long, narrow and
flattened shapes. The grain length is between
5 and 9mm, weight of grain is almost 35 and 50mg and has a line down one side where it was formerly linked to the wheat flower.
The wheat grain (Fig) 13-17% bran, contains 2-3% germ and 80-85% endosperm Belderok
et al., 2000.
(from Encyclopaedia Britannica, http://www.britannica.com)
The bran is made up of numerous layers, which defend
the major element of the grain. Bran is loaded in B vitamins
and minerals; bran is separated from endosperm at the initial stage of milling. Bran
comprises water-insoluble fiber layers which protect the endosperm. Bran
consists of fiber (53%). Wheat bran has a complex chemical it contains, cellulose and
pentosans, xylose and arabinose polymers are there which are firmly bound
to proteins. These polymers are there in cell walls of wheat and in aleurone
layer. 16% Proteins and carbohydrates each present of total dry
matter of bran. The ash substance is (7, 2%). The two outer layers of the wheat
(seed coat and pericarp) are composed of dead cells. The cells of the inner bran
layer- aleurone are packed with living protoplasts. This explains the quite elevated
levels of carbohydrate and protein in the bran. There are big differences
among the amount of c amino acids in aleurone and those in flour.
Levels of glutamine and proline are only one half alanine,
asparagine, glycine, histidine and lysine are double in
wheat flour Cornell 2003
The endosperm is bounded by the complex seed coat and pericarp. The external endosperm, the aleurone,
has a particular arrangement: it composed of single coat of cubic produced
cells. The aleurone is
wealthy in enzymes and proteins, which play an essential role in the
germination Belderok et al., 2000.
The epidermis composed of a only layer of cells that
form exterior of the kernel. On the outer side of the epidermal cells is the
water-impermeable cuticle. Hair forms due to the formation of epidermal cells
at the apex of grain.. The hypodermis is made of one or two layers of cellsLasztity
The germ present at one side of the grain. It is
high in proteins (25%) and lipids amounts (8-13%). The ash level is also high
(4,5%). Wheat germ is accessible as a split body because it is a
significant supply of vitamin E Cornell 2003.
As a consequence of the arrangement of a protein, single
cells of wheat ?our include networks of gluten, which are brought mutually while
dough making. The specific changes that happen in the dough while mixing are
still not completely understood, but a raise in dough rigidity occurs that is
usually considered from ‘optimization’
of protein–protein connections within the gluten network. In molecular terms,
this ‘optimization’ it include replace of disulphide bonds as addition in air,
oxygen and nitrogen has effects on the sulphydryl and disulphide stuffing of dough
Tsen & Bushuk 1963; Mecham & Knapp 1966.
Grading systems make easy marketing by determined to
meet necessities of the buyers and provide motion to growers to produce
preferred quality for reasonable returns Hulasare, et al. Grading is the separation
of grain into packages of distinct worth to facilitate value determination Canadian
Grain Commission (Cele, 1993.A good grading method must realize the following:
Guarantee the manufacturer a fair grain
price relation to its value.
Facilitate grain management by
encouraging the joint storage of lots of similar class.
Set up a system of relating prices to
value to simplify trading.
Allow the buyer to constantly get the
same feature of grain.
Divide grain into a adequate number of class
so that the consumer have a variety of grades, but at the same point, limit the
quantity of grades to make easy management and storing in a well-organized
bulk-handling system Hulasare, et al.
Exporting countries revised their grading system
frequently to adapt to varying global trade in grain, according to buyer
preferences Hulasare, et al. In the United States, an early step was taken by
the Chicago Board of Trade in 1856 by establishing grades for wheat and corn
Cronon, 1991. In southern Russia at the beginning of the 19th
century, a grading system was introduced but the grading or handling system was
failed, owing to public and technical factors. Argentina and Australiaalso
introduced such systems in 19th century at that time they were
failed. Canada introduced grading system in 1863 Hulasare, et al.
When Midwest grain fields of U. S. opened, extra
grain was moved by river, wagon, or rail to Milwaukee and Chicago for forward
movement to Canada or the eastern part by sea of the U. S. and later to Europe
in 1858 Irvine, 1983 American grades are following.
Club wheat: clean. 60 lb per Winchester
bushel (a cylinder with a diameter of 18.5 in. and a depth of 8.0 in.) (780
No. 1 Spring: clean. 56 lb per
Winchester bushel (725 kg/m3).
No. 2 Spring: reasonably clean. 50 lb
per Winchester bushel (650 kg/m3).
Rejected: 40 lb per Winchester bushel
(520 kg/m3). Hulasare, et al
Fair Average Quality System Represent
ting samples are prepared in this method which represent the quality of whole
batch and send to buyers to ensure that Quality will be same. Buyers match the
quality of shipment with sample. Only some countries use this method (CGC,
Numeric System The numeric system divides the
grains on the basis of quality factors that are defined by grading factors.
Each distribution is recognized by a grade name or number, and grain is buying
and sold on the basis of these grades. Buyers attain the precise quality
desired by choosing the grade. In some grading, a certificate of grade is enough
to an importer, and no extra samples are necessary as proof of quality. In
other systems, importers claim extra safeguards CGC, 1993.
Maximum limits of foreign mater
Other factors affecting grading ( dockage, moisture,
protein content) CGC,1993a
Table Comparison of
Standard of Quality and Tolerances for the United
States, Australian. and Canadian•Grading Systems for
No. I (Top Grade) Wheat
Standard, of quality/maximum limits
(U. S. No. 1
Canadian (No. ICY:RS)
Standard of quality
Minimum test weight (kg/hL)
Any %finches of red spring wheat equal to or better than
Minimum hard vitreous kernels
Degree of soundness
matured and free from damaged kernels.
Other than cereal grains
Total (including cereal grains)
Screenings below the screen
Screenings above the screen
Wheats of other classes or varieties
(pan of total percentage)
extensively qualitative and quantitative losses happen because of some factors, such as ecological factors
(moisture content, temperature of grains, humidity,
pH, etc), type of storage arrangement used, span and purpose of storage, technique of storing grains, and natural
factors (pests, insects, microorganisms and rodents). Nowadays, the grains ares stored using the improved methods, by
using bags, silos, sheds, containers and
even in piles on the ground managed as
artificial ecosystems Said, yet al 2014In developing
countries grains are stored at farmers, traders and a few at industrial levels.
Suitable equipment for management and storage of grains are been developed in
all parts of the world. Grain storage structures
are a group of devices for grains used after harvesting to until their
utilization or transport in a different place Tiwari et al., 2012. Grain storage is a constituent in the
grain market supply sequence that evens out fluctuations in the supply of grain
from harvest period to other seasons, and from one year of plentiful supply and
releasing to lean years. Grain storage perhaps at farm, trade or at government
levels (Mushira, 2000)
Storage losses also differ geologically
depending on the kind of storage structures used Usha and Mohan, 2007.
The predicted postharvest
losses are 3.82 kg/ q for rice and 3.28 kg/q for wheat at the farm level in India
in 2003-2004 Basavaraja et al., 2007.
Conventional storage practices do not
assurance safety against chief storage pests of staple food crops, cause high proportion
of grain losses, mostly due to post-harvest insect and grain pathogens Tefera
et al., 2011. Traditionally, there are two approaches employed for grain storage:
temporary storage and long-term storage methods Mishra, et al, 2012