Background and literature
agriculture, plants are classified as crops and weeds where the former named
plants are those useable and weed are those which are useless or those growing
somewhere that are not needed. The crops are specified as two main large groups
namely horticultural and agronomic crops. The crops are subdivided into smaller
groups i.e. food and non-food crops, cereals, root and tuber crops, pulses,
fruit and vegetable crops, and further more.
of the most important food crops is Wheat which is the most used and comes
first in the list of cereal crops worldwide in term of manufacturing and area.
Wheat can grow almost anywhere on the earth such as in harsh weather condition
and/or on different soil types due to its typical adaptability characteristics.
The overall wheat yields in the world in the year 20011 to 2012 was approximately
700 million tonnes from the planted field of around 2.18 million square
characteristics are considered in wheat quality which the most important one is
the grain hardness. The quality of wheat is also depends
on several other factors such as type, environmental variables and the genetic
nature. Environmental condition has
major effect on the quality and quantity of the wheat proteins according to (Randall and Moss, 1990; Johansson and
Svensson, 1998; Samaan et al., 2006) while protein quantities influenced by
the nitrogenous fertilizers.
grain is mainly consists of three parts with different chemical configuration
(endosperm 75-82%, bran 12-16% and germ 2-3%), hence affecting the crops
production. In the endosperm the protein and starch granules are stored which
are having very important role in the flour and end product quality. Enzymes,
vitamins, minerals and non-starch polysaccharides are contained in the second
part (bran). Thirdly, wheat germ is a small portion but comprises with
vitamins, edible fats and good quality proteins (Karim and Sultan, 2014).
empirical instrument used to investigate the mechanical behaviour of the wheat
flour dough which is called Farinograph instrument (Walker and Hazelton, 1996). Other researchers have tested the
fundamental viscoelastic properties of dough rheology which among them Schofield and Scott-Blair (1932) were
the first researchers to study dough system. Wheat flour dough was the most
attracted dough structure by the authors for further investigation due to its
unique viscoelastic behaviour in forming dough which is from the wheat protein
characteristics (Bloksma, 1990;
Szczesniak et al., 1983).
Dreese et al., (1998)
has reported on the rheology of wheat flour constituents such as gluten which
is considered as the most important factor to produce elasticity in the wheat
flour dough. Extensive studies performed by (Dubois, 1983; Szczesniak et
al., 1983; Eliasson, 1981; slade et al., 1998) on the dough components hence
gluten, starch, lipid and water content in the mixture to investigate the dough
rheology behaviour. Rheological evaluation has been utilised to study the flour
quality and other parameters like elasticity and viscosity of the dough are
also considered as valued factors in the flour quality measurement (Ognean et al., 2011).
rheological factors are always critical in the bakery marketing and production because
it is helping the producers to have the overall idea about the end use of flour.
Also rheological properties study is helping to specify the ingredients,
quality control and stabilizers to input in the elaborated products which also
have a direct effect on its processing and end use quality (Samaan et al., 2006).
Table 1: Wheat quality parameters
hardness, weight, shape and test weight.
Flour yield, pearling quantity, amount produced, cleanliness and
quantity and quality of wheat protein via sedimentation test.
Wheat proteins, oils, carbohydrates, moisture, gluten, great
molecular gluten protein and decreasing quantities
Farinographic characters (water, dough development and stability
durations). Mixing characteristic (i.e. mixing time and mixing tolerance
Aims and objectives:
study is planned to investigate the physio-chemical properties and rheological
behaviour of some cereals products dough from various available cultivars
hence; wheat flour productions. Also to outline the factors which are affecting
the production quantities and end user qualities.
Materials and Methods:
There are varies methods used by
researchers for testing wheat grades and flour qualities which have direct
relation to the production of cereals with different cultivars. Rheological properties of
the flour can be assessed by running via Farinographic instrument (ICC-Standard
115:1, 1992; AACC Method No. 54-21, 1995) which is equipped with a bowl of 50g
capacity according to method included in American
Association of Cereal Chemists AACC
following continuous flour weight process. Then the results for the mixing characteristics
and resistance are recording on a diagram
and the farinograms calculated for physical dough behaviours hence; dough settlement
time, stability, mixing progress and softening of dough to conclude the
strength level (weak or strong) of wheat flour for crops suitability.
Chemical analysis is also used to investigate the
quality of flour produced from the wheat variety according to the guidance
provided in AACC (2000) which
involved in testing for composition percentage contents such as
moisture, basic protein, fat, primary fibre, dust, SDS test, gluten content
(wet and dry).
analytical method is using to evaluate the effectiveness of different wheat and
flour qualities containing in a product from the data obtained for each
parameter. Further to study flour quality by using completely randomized design
and mean values achieve from the statistical analysis for each properties then
comparing the results according to DMR study (Steel et al., 1997) where the level of significance ? = 95, p < 0.05 used. Sampling and testing: Most mills test at intake for screenings, the presence of moisture, specific weight, Hagberg Falling Number, protein levels and hardness. The sampling is important for wheat quality in order to meet the milling requirements which mean samples should be free from ergot, broken, heat-damaged, odours or taints, insect infestation, moulds, sprouted, shrivelled, pink or green grains, as stated in ISO 24333:2009 (specifies requirements for the dynamic or static sampling) and also further information about grain sampling provided in HGCA (2013). A fast testing for mycotoxins is normally performed at the start of each new harvest season and on randomly selected loads as part of a 'due diligence' process. The frequency of mycotoxin testing will vary from one year to another and within different industries.