• Aldehyde : Any class of organic compound containing
the CHO group. A by-product formed in oxidation.
• Alkali : Any soluble substance that can neutralize
acids. Has a pH greater than 7.0.
• Crystals, a, b, b1 : When triglyceride molecules in
a fat turn from a liquid to a solid as a result of
decreasing temperature, they pack into one of three
different types of arrangement. Crystal forms exist
only when the fat is in the solid state. They can
affect the physical properties and functionality of
• Emulsifier : A material that lowers the surface
energy between two immiscible phases (e.g. oil and
water), thus facilitating the dispersion of one phase
into the other.
• Emulsion : A homogeneous dispersion of two
dissimilar immiscible liquid phases. If oil is dispersed
in water, it is an oil-in-water (O/W) emulsion. If water
is dispersed in oil, it is water-in-oil (W/O) emulsion.
• Glycerides : Compound that have one or more
fatty acids attached to glycerol.
• Glycerol : A three-carbon chain, with each carbon
containing an alcohol group. One, two, or three fatty
acids may be attached to glycerol.
• Hydrolysis : A chemical reaction in which a substance
reacts with water so as to be changed into
one or more other substances, such as natural fats
into glycerol and fatty acids.
• Lipids : A class of organic compound consisting
of the fats and other substances of similar properties
that are insoluble in water, soluble in organic (non
polar) solvents such as ether or hexane. Triglycerides,
cholestrol, and vitamin A are examples.
• Miscella : The mixture of solvent and oil that occurs
during the solvent extraction of oil from oil seeds.
• Monounsaturated : A fatty acid that has one
double bond (C=C) in the carbon chain. Oleic acid
is an example.
• Peroxide value : A number that indicates the level
of peroxides in a fat or oil that has developed as
a result of oxidation. Peroxides are considered
intermediates in the lipid oxidation reaction scheme.
• Phospholipid : A natural component of fat that has
a phosphate ester associated with the glyceride. It
is a surfactant that aids emulsification.
• Plasticity : A physical property of a fat that
describes how soft, pliable, and mouldable it is at
a given temperature.
• Polar lipids : Fat components that are more like
water and less like fat in their solubility properties.
Introduction of oxygen or nitrogen atoms into lipid
molecules makes them more polar.
• Polyunsaturated : A fatty acid that has more than
one double bond (C=C) in the carbon chain. Linoleic
acid is an example.
• Saturated : A carbon chain in which the carbons
are connected to each other by single bonds, drawn
as C-C. It has no carbon-to-carbon double bonds.
• Stearin : A white, crystalline substance found in the
solid portion of most animal and some vegetable
• Surfactant : A chemical compound that lowers the
surface tension between two dissimilar phases
such as oil and water.
• Abrasive polisher : A machine used to remove
bran from brown rice, using abrasive action between
the kernel and the emery stone. Also called
• Aspiration : A process of cleaning by moving a
large volume of air through a thin layer of grain,
to separate particles lighter in weight than grain.
• Aspirator : Machine used to separate particles
lighter than grain by moving air through a thin layer
• Bran : The outer covering of rice kernel after the
husk is removed. It is removed during polishing.
• Bran stabilisation : Heat or other treatment given
to Rice bran to stop deterioration of its oil.
• Brokens : Pieces of the rice kernel that are less
than three fourths the size of the full kernel.
• Brown rice : Dehusked rice grain obtained after
dehusking paddy. Also called unpolished rice,
• Carborundum : An artificial abrasive, whose hardness
is about two and a half times that of emery.
Chemically it is silicon carbide.
• Chalky grain : Kernel of grain which has some
portion as opaque or milky white in appearance.
• Cyclone separator : Large, round, tank-like structure,
usually metallic, used to separate particles
carried in an air stream.
• Degree of polishing : Expression used to indicate
the amount of bran removed in the milling process.
Represents per cent by weight of brown rice
removed as a fine powder during polishing. Also
referred to as degree of milling.
• Dehusking : The process of removing husk from
paddy during milling. Also called shelling.
• Destoner : A machine that separates stones from
grain. Usually used to separate stones of same size
as the grain.
• Discoloured grains : Paddy or rice grains, which
have changed to yellowish or brownish or black
colour because of heat or insect damage during
• Dockage : Chaff, immature grains, other seeds,
sand, stones or other impurities found in a sample
• Drying : The process of reducing the moisture
content in the grain.
• Dunnage : Wooden frames used on concrete
floors for stacking bags of grain. It prevents direct
contact between the grain and the floor.
• Emery : Naturally available abrasive material used
in some shellers and polishers.
• Foreign matter : Materials such as stones, sand,
chaff, straw or other seeds, mixed with the paddy
• Friction polisher : Equipment used to polish brown
rice using friction between the rice grains. Also
• Fumigation : The process of using gaseous
chemicals to control insects in grain.
• Grading : The separation of broken rice grains
from unbroken rice and separation of brokens of
• Head rice : The karnels of milled rice which are
three-fourths the size of full rice or longer.
• Head yield : The amount of head rice obtained
when paddy is milled. It is the total rice minus the
• Holding capacity : The amount of paddy a dryer
or a bin can hold. It is not necessarily the drying
capacity nor the through put capacity of the dryer.
For example, a continuous flow dryer may have a
6 tonne holding capacity, a 12 tonne through put
capacity, and an average drying capacity of 2
tonnes per hour.
• Hull : See husk.
• Huller : Engelberg huller, widely used as a small
capacity rice mill. Removes both husk and bran
from paddy in one operation.
• Husk : Outer covering of the paddy grain. Also
• Immature grains : Paddy grains which are not fully
developed, usually green and thinner and lighter
compared to a fully mature grain.
• Ksc : Kilogram per square centimeter.
• Milled rice : Rice obtained from paddy after the
husk and bran have been removed. Also called
• Milling : A general term representing the process
of converting paddy into rice. Sometimes the term
refers specifically to the act of bran removal, i.e.
• Milling yield : The amount of milled rice obtained
from paddy after the milling process. When used
as a general term, it means brown rice yield, total
milled rice yield and head rice yield.
• Moisture content : Amount of water in the grain.
Expressed as a per cent based on wet or dry
• Paddy separator : machine used to separate the
mixtue of paddy and brown rice obtained after
• Parboiled rice : Rice obtained from paddy that had
been soaked, then steamed and then dried.
• Pearling : See polishing.
• Polishing : The process of removal of bran from
brown rice. Also called whitening, pearling, milling.
• Raw Rice : Rice milled from paddy which has not
• Sample divider : Laboratory device to prepare
small representative samples from a larger lot.
• Scalping : Rough cleaning of paddy removes most
foreign matter prior to drying and storage.
• Screen : A sieve. A perforated metal sheet having
round, oblong or rectangular opening or wire mash
having square or rectangular openings.
• Sheller : Machine used to remove husk from
• Shelling : The process of removing husk from
paddy. See dehusking.
• Sifter : Machine used for sieving impurities smaller
or larger than paddy grains.
• Tempering : Temporarily holding the paddy between
drying passes. It allows the moisture content
in the centre of the grain to diffuse to the surface
and the moisture to get equalised throughout. Total
milling yield / total rice, including head rice and
broken rice milled from paddy. Usually expressed
as per cent of paddy milled.
• White belly : Chalky portions in the milled rice
• Whitening : See polishing.