process involved in edible/cooking oils industries.(refining process)

                                

                                        Edible Oil Processing

Raw martials :

·        RBD , SOYBEAN OIL , SUNFLOWER , RAPESEED OIL (RSO) ,PALM OIL

·        COOTEN SEED OIL , CANOLA ,OLIVE ,CORN OIL  ,PALM KERNOL OIL

·        COCONUT OIL ,GROUNDNUT OIL ,LINSEED OIL.

Introduction:

 Vegetable oils are an important part of the human diets world-wide and their production by extraction processes greatly increased in the last century due to higher request and consumption, the increase in world population and the progressive availability of more efficient process technologies and equipment. Edible oils are widely used by food industry due to their nutritional properties and their influence on the smell and taste of food products.

During the industrial production of vegetable oils and oil is assigned to oil that is not processed after being extracted from the animal or plant material. In order to become suitable for human consumption, crude oils are generally refined to remove the majority of these unwanted components to produce a stable product with desired color and a pleasant taste, with the least possible damages on desirable components and with the least possible loss of oil (Suliman et al., 2013). In general, refined oil is clear, odorless, and resistant to rancidity.

Process :

The traditional refining process of crude vegetable oils generally includes the steps of

* DEGUMMING,

*NEUTRALIZATION,

* BLEACHING AND

*DEODORIZATION.

Explanation of process :

The fats and oils obtained directly from

rendering or from the extraction of the oil seeds are:

termed “crude” fats and oils. Crude fats and oils contain

varying but relatively small amounts of naturally

occurring non-glyceride materials that are removed

through a series of processing steps. For example, crude

soybean oil may contain small amounts of protein, free

fatty acids, and phosphatides which must be removed

through subsequent processing to produce the desired

shortening and oil products. Similarly, meat fats may

contain some free fatty acids, water, and protein which

must be removed.

It should be pointed out, however, that not all of

the nonglyceride materials are undesirable elements.

Tocopherols, for example, perform the important

function of protecting the oils from oxidation and

provide vitamin E. Processing is carried out in such a

way as to control retention of these substances.

*Degumming

Crude oils having relatively high levels of

phosphatides (e.g., soybean oil) may be degummed

prior to refining to remove the majority of those

phospholipid compounds. The process generally

involves treating the crude oil with a limited amount of

water to hydrate the phosphatides and make them

separable by centrifugation. Soybean oil is the most

common oil to be degummed; the phospholipids are

often recovered and further processed to yield a variety

of lecithin products.

A relatively new process in the United States is

enzymatic degumming. An enzyme, phospholipase,

converts phospholipids, present in crude oil, into

lysophospholipids that can be removed by

centrifugation. Crude oil, pre-treated with a

combination of sodium hydroxide and citric acid, is

mixed with water and enzymes (phospholipase) by a

high shear mixer, creating a very stable emulsion. The emulsion allows the enzyme to react with the phospholipids, transforming them into water-soluble lysophospholipids. This emulsion is broken by centrifugation, separating the gums and phospholipids

from the oil. This process generates a better oil yield than traditional degumming/refining. Enzymatic degumming is currently not widely commercialized.

Refining/Neutralization :

The process of refining (sometimes referred to as “alkali refining”) generally is performed on vegetable

oils to reduce the free fatty acid content and to remove

other impurities such as phosphatides, proteinaceous,

and mucilaginous substances. By far the most important

and widespread method of refining is the treatment of

the fat or oil with an alkali solution. This results in a

large reduction of free fatty acids through their

conversion into high specific gravity soaps. Most

phosphatides and mucilaginous substances are soluble in

the oil only in an anhydrous form and upon hydration

with the caustic or other refining solution are readily

separated. Oils low in phosphatide content (palm and

coconut) may be physically refined (i.e., steam stripped)

to remove free fatty acids. After alkali refining, the fat or

oil is water-washed to remove residual soap.

Operation involve

·        The raw material is heated up to 45C.

·        After this check its FFA%

·        Then phosphoric acid is shower according to the batch almost 10 kg is given to 20Ton batch, its remove the gums.

·         Then caustic soda is shower according to the FFA% in the batch. Almost 5 to 8 inch are given. (20 to 22 baumi solution of caustic soda).

·        Then heat the batch up to  70 to 75C. 20kg of salt is given to 20 Ton batch

·        Then wash with hot water (several  wash till the soaps removed)

·        After the first wash wait for 2 to 3 hours to settle down the soaps and the soaps should be removed.

·        Again the batch heated  up to 95 to 98C and at 90C again give 20kg of salt after 3^rd wash.

·        Check the soaps content after every wash …..

Bleaching tank :

The term “bleaching” refers to the process for

removing color producing substances and for further

purifying the fat or oil. Normally, bleaching is

accomplished after the oil has been refined.

The usual method of bleaching is by adsorption

of the color producing substances on an adsorbent

material. Acid-activated bleaching earth or clay,

sometimes called bentonite, is the adsorbent material

that has been used most extensively.

This substance consists primarily of hydrated aluminum silicate.

Anhydrous silica gel and activated carbon also are used

as bleaching adsorbents to a limited extent.

Operation involve

After from neutralizer tank the batch goes to bleaching tank

·        First the sample is charged in bleacher.

·        Then dry the batch in bleacher for 10 to 15 mints.

·        Then according to the color the bleaching earth is given at 100C and 280 to 300mmHg pressure about 500kg is given to per 20 Ton batch.

·        The bleaching process remain for 45mints .

·        From bleacher the batch goes to filter where the color is checked.

·        After the filtration the batch goes to pre tank which taks about 2 to 3 hours.

Deodorization

Deodorization is a vacuum steam distillation

process for the purpose of removing trace constituents

that give rise to undesirable flavors, colors and odors in

fats and oils. Normally this process is accomplished after

refining and bleaching.

The deodorization of fats and oils is simply a

removal of the relatively volatile components from the

fat or oil using steam. This is feasible because of the

great differences in volatility between the substances that

give flavors, colors and odors to fats and oils and the

triglycerides. Deodorization is carried out under vacuum

to facilitate the removal of the volatile substances, to

avoid undue hydrolysis of the fat, and to make the most

efficient use of the steam.

Deodorization does not have any significant

effect upon the fatty acid composition of most fats or

oils. Depending upon the degree of unsaturation of the

oil being deodorized, small amounts of trans fatty acids

may be formed. In the case of vegetable oils, sufficient tocopherols remain in the finished oils after

deodorization to provide stability.

Operation involve

^·         At 110C about 2.5kg citric acid is given before entering to D tank

^·         From pre tank the batch goes to D tank. Where the batch is heated up to 150C.

^·         Than high vacuum valve is open to remove the moisture contents and dust particles  etc.

^·         The high vacuum is start for 4 hours , this process is carried in heating which means that the heater is on.

^·         At 130C the high vacuum is closed.

^·         At 80 to 90 C the cooling is start in the presence of low vacuum .

^·         When the batch is cool then its goes to final filter.

^·         In final filtration unit the flavors vitamins(A&D) are given.

Hydrogenation process

 This process is used to control the melting pointing of ghee.

It maintains the temperature from 35 to 37C.

It also gives granular stricture to ghee.In this process Nickel is used as a catalyst and hydrogen gas is passed for 2 to 3 hours at 140 to 145C.

Block diagram for whole process

Tanker => feed tank => neutralizer tank1=>  neutralizer tank2 =>  bleaching tank B1 => filter unit => pre tank => hydrogenation tank =>  cooler => neutralizer tank3 =>  cooler =>  bleaching tank2 (post tank) =>  filter unit => storage tank => deodorization tank D1(ghee) => cooler => deodorization tank D2 (oil) =>  cooler => polish filter => filling tank => filling section => cooling of packing => storage room.

For quality assessment involves in edible oil industries click here.