FE-401 FOOD TECHNOLOGY

REFINED OLIVE POMACE OIL

INTRODUCTION

Olive pomace is the pulpy residue from olives after pressing.

The total of olive weight, the pomace 70 – 90 %, the stone 9-27% and the seed about 2-3%.

Pomace contains about 2-8 % residual oil.

Olive pomace oils, obtained by refining of the oil extracted from the olive pomace.

The purpose of processing the remaining pulp from olive oil production is to produce edible oil.

Olive pomace should be delivered immediately  to the extraction factory (on the same day it is produced) for drying in order to avoid any increases in acidity in the olive-pomace oil.

 After drying, pomace extracted by hexane to yield raw olive-pomace oil

Raw olive-pomace oil must be refined to become edible.

The edible product sold as olive-pomace oil is refined olive-pomace oil

PROCESS STEPS

1)DRYING THE POMACE

2)EXTRACTION

3)DISTILLATION

4)REFINING

FLOWCHART

DRYING

Halt the fermentation of the pomace.

Carried out by blowing hot air over the pomace in a drum screen.

Lower the moisture content to around 5-6%

The hot drying gases are used at high

temperatures (400°C to 700°C).

Final temperature of finished product not more than 70–80 °C.

EXTRACTION

 Preparation of the fatty pulp

 Extraction with hexane

 Desolventizing of the extracted pulp

  Types of Extractors

Batch Extractor

    Pulp placed in an upright reactor

and sprayed with the hexane.

    Commonly used for extraction.

Continuous Extractor

    Pulp washed with hexane.

DISTILLATION

Distillation of the oil-hexane mixture (miscella) in a distiller.

Try to remove the hexane from the oil as soon as possible at a temperature of around 100–110 oC.

The finished product to be lower than 150 ppm of hexane in oil.

WHY DOES IT NEED REFINING ?

Because ;

The crude pomace oil obtained is a high acidity (more than 3% as oleic acid)

Dark green oil (high chlorophyll content)

High waxes content

Unpleasant odor and taste.

REFINING

Degumming

Neutralization

Bleaching

Winterization

Deodorization

DEGUMMING

Achieved by hydrating the gums using 0.1% concentrated phosphoric acid

Reduction of phospholipid content.

Precipitation with acids.

To remove precipitate.

NEUTRALIZATION

The crude pomace oil obtained is a high acidity (more than 3% as oleic acid)

Removes nearly all free-fatty acid by converting them into oil-insoluble soaps.

The oil-insoluble soaps are separated by centrifuge in the batch neutralizers.

Chemical reaction with caustic soda.

Caustic soda + Acid        Soap + Water

BLEACHING

Remove the unpleasant colors of the alkali neutralized pomace oil

The oil is heated to 100℃.

Stirred with the bleaching earth for 30 min under a vacuum (30-40 mmHg)

Bleached oil removed from the activated earth and charcoal by filtration.

WINTERIZATION

The elimination of any compound that might cause the final product to appear cloudy

Removes waxes and high melting triacylglycerols.

The process is based on crystallization (5–8 ℃).

Increase the size of crystals.

The crystals are separated with filtration.

DEODORIZATION

Final treatment step in the refining process.

Treatment of undesirable odours.

150 ℃ to  260 ℃.

Steam is used to better tastes and aromas

 Absolute vacuum between 0.2– 0.4 mbar.

IMPORTANT ANALYSIS

 1)DETERMINATION of FATTY ACID CONTENTS

 2)DETERMINATION of WAXES

 3)DETERMINATION of FREE FATTY ACIDS (FREE ACIDITY)

 4)DETERMINATION of PEROXIDE VALUE

 5)DETERMINATION of STIGMASTADIENES

 6)DETERMINATION of STEROL COMPOSITION

 GENERIC CHEMICAL COMPOSITION PARAMETERS

QUALITY PARAMETERS

Thanks for your attention

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