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Comparative study of extraction and characterization of avocado oil,

through processes of: thermobeating, enzymatic, hydraulic pressing

and expeller.

Estudio comparativo de extracción y caracterización del aceite de

aguacate, mediante procesos de: termobatido, enzimático, prensado

hidráulico y expeller.

Miroslav Gonzalo Alulema Cuesta

*; Joselin Patricia Estrada Gaybor

; Kenia Doménicka Morocho Salazar

Received: 12/03/2024 – Accepted: 10/06/2024 – Published: 01/07/2024

Research

Articles

Review

Articles

Essay

Articles

* Author for correspondence.

Abstract.

Avocado (Persea Americana Mill.) is a raw material rich in oil, which is why its extraction and production can be considered an industrial option, since

it is attributed several beneficial properties for health. The objective of this work was to carry out a comparative study to obtain avocado oil, Hass variety,

by four different methods (thermobeating, enzymatic, hydraulic pressing and expeller), specifying significant differences and determining the best method

in terms of performance and quality. The performance variable was calculated on a dry basis, with the Thermobeating method having the highest

percentage with 89.78%. Physicochemical tests such as humidity, density, acidity index, peroxide index, saponification index and iodine index were

carried out on the oil samples obtained, obtaining the best results in the thermobeating method, with the exception of the peroxide index and whose values

were: 0.054%, 0.9039 g/mL, 3.13 g/100g, 78.87 meqO2/kg, 190.06 mkOH/mg, 84.56cg/g respectively. On the other hand, regarding the composition of

fatty acids, High Pressure Liquid Chromatography (HPLC) was carried out, where the hydraulic pressing method generated the best values, which were:

23.57 g/100g, 64.29 g/100g, 12.14 g/100g. 100g, 0.48 g/100g, 11.65 g/100g, 61.07 g/100g, 21.00 g/100g and 1.26 g/100g for Saturated, Monounsaturated,

Polyunsaturated Fatty Acids, Omega 3, 6, 9, Palmitic Acid and Stearic Acid, respectively. Finally, these values were contrasted with experimental data

from other investigations together with those of a commercial oil, finding values close to those reported.

Keywords: Avocado, thermobeating, enzymatic, hydraulic pressing, expeller pressing, high pressure liquid chromatography (HPLC), fatty acids.

Resumen.

El aguacate (Persea americana Mill.), es una materia prima rica en aceite, por lo cual su extracción y producción puede considerarse como una opción

industrial, ya que se le atribuye varias propiedades beneficiosas para la salud. El objetivo de este trabajo fue realizar un estudio comparativo para la

obtención de aceite de aguacate, variedad Hass, por cuatro métodos distintos (termobatido, enzimático, prensado hidráulico y por expeller), especificando

diferencias significativas y determinando el mejor método en términos de rendimiento y calidad. La variable de rendimiento se calculó en base seca,

siendo el método de Termobatido el que presenta el más alto porcentaje con 89,78%. A las muestras de aceite obtenido se les realizó pruebas

fisicoquímicas como humedad, densidad, índice de acidez, índice de peróxido, índice de saponificación e índice de yodo, obteniéndose los mejores

resultados en el método de termobatido, con excepción del índice de peróxido y cuyos valores fueron: 0.054%, 0.9039 g/mL, 3.13 g/100g, 78.87

meqO2/kg, 190.06 mkOH/mg, 84.56cg/g respectivamente. Por otra parte, respecto a la composición de ácidos grasos se realizó Cromatografía Líquida

de Alta Presión (HPLC), donde el método de Prensado hidráulico genero los mejores valores, los cuales fueron: 23.57 g/100g, 64.29 g/100g, 12.14

g/100g, 0.48 g/100g, 11.65 g/100g, 61.07 g/100g, 21,00 g/100g y 1.26 g/100g para Ácidos Grasos Saturados, Monoinsaturados, Poliinsaturados, Omega

3, 6, 9, Acido Palmítico y Acido Esteárico, respectivamente. Finalmente se contrastó estos valores con datos experimentales de otras investigaciones

junto a los de un aceite comercial, encontrándose valores cercanos a los reportados.

Palabras clave: Aguacate, termobatido, enzimático, prensado hidráulico, prensado por expulsor, cromatografía líquida de alta presión (HPLC), ácidos

grasos.

1.- Introduction

In Ecuador, about 20 varieties of Avocado are produced; the

most well-known are: Guatemalan, Creole, Hass, and

Fuerte. In recent years, it has become an agro-export

activity. Avocado cultivation in Ecuador is gaining more

importance year after year. Its high yield in adequate

climatic conditions and the great demand in the

Universidad de Guayaquil; miroslav.gonzaloa@ug.edu.ec; https://orcid.org/009-001-6527-7567, Guayaquil; Ecuador

Investigador Independiente; joselinestrada1997@gmail.com; https://orcid.org/0009-008-7187-1344, Guayaquil; Ecuador.

Investigador Independiente; _domenicka@hotmail.com; https://orcid.org/0009-004-0499-0424 , Guayaquil; Ecuador.

international market have placed this product in a privileged

position in the country [1].

Among its qualities, avocado has been attributed

characteristics of beautifying the skin and also aphrodisiac

properties. The avocado tree, depending on the variety, can

grow in territories located both at sea level and at 2,500 m

altitude, in the warm inter-Andean valleys of the country

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[2]. Therefore, this research will provide relevant

information for both Chemical Engineering students and

other related careers, and eventually for people who want to

start a profitable business, as they will have the theoretical

bases of the different methods and processes of obtaining

avocado oil experimented in this work, which will be

detailed throughout its content, thus considering its

extraction and characterization, for which fatty acid profiles

of the various extraction methods were performed, and

compared with commercial brands, to achieve in this way

the comparative study proposed previously.

To achieve the general objective of: Conducting a

comparative study for obtaining avocado oil by four

different methods (thermo-beating, enzymatic, hydraulic

pressing, and expeller), specifying significant differences

and determining the most beneficial method in terms of

yield and quality, the following specific objectives were

proposed:

• Extract the oil by various extraction methodologies

(thermo-beating, enzymatic, hydraulic pressing, and

expeller) of avocado oil at laboratory level, and

determine the best yield in terms of productivity.

• Physicochemically characterize the extracted oil,

through tests of: Moisture, Density, Acidity Index,

Saponification Index, Peroxide Index, Iodine Index.

• Perform a Fatty Acid profile of the oils obtained from

avocado (Hass Variety) using High-Pressure Liquid

Chromatography (HPLC) and determine the best

extraction method in relation to the quality of the

extracted oil.

• Compare the results obtained through physicochemical

analysis and HPLC of the most suitable method found

in the research with the best quality characteristics of

an experimental product and another present in the

market.

This study can be a reason to promote the added value that

would be given to the export output of avocado and develop

a non-traditional natural export product such as oil, this

being a quality product with future perspectives through the

use of new and better technologies, and not just

commercialize it as a fruit.

1.1.- Thermo-beating Process

According to what Cueva Cabrera [3] indicates, this is the

process responsible for separating liquids, oils, and solids,

so in the future they will not have much resistance to the

extraction of elements. The thermal treatment consists of

using the previously obtained pulp and pouring it into a

rotating drum, in the rotating drum there is a series of

paddles that are responsible for emulsifying the product at

low speeds and temperatures not exceeding 45ºC to avoid

damaging the product. In some oil extraction processes,

when the temperature rises above the specified temperature,

many vitamins, aroma and flavor characteristics can be lost;

in some cases, when this characteristic exceeds its tolerance,

trans fats are often produced. Therefore, this saturated oil

does not result in a 100% healthy product.

1.2 Enzymatic Process

The oil extraction technique using enzymes has emerged as

a promising method for oil extraction. This process uses

suitable enzymes to extract oil from crushed seeds. Among

its main advantages, it stands out for being environmentally

friendly, as it does not generate volatile organic compounds

as is generally the case in the solvent extraction process.

However, the processing time for oil extraction is

considerably longer compared to the previously described

mechanical extraction, which constitutes the main

disadvantage associated with this alternative [4].

The use of enzymes shares its own benefit with the

environment. Different studies suggest that enzymes can be

used to improve oil production in vegetable oil and fat

extraction processes, where unconventional solvents are

used, and can also be immobilized for recovery and reuse,

which can help reduce processing costs [4].

Pectinases. Pectinases hydrolyze different types of pectins,

releasing uronic acids. The biodegradation of pectins is

carried out thanks to pectinases and specifically

endopolygalacturonases, which only act on acid (non-

esterified) units. Esterified units are degraded by methyl

pectin esterases, which allow the substrate to adapt to react

with the previous enzyme. In the case of highly methylated

pectins, only pectinlyases of bacterial origin have the ability

to hydrolyze them [5].

1.3 Hydraulic Process.

There are several types of compression molding that use

different techniques to form a semi-dry method, although

most methods are actually the same or similar, the final

characteristics of the product justify the use of one

technique or another. The hydraulic pressing process is

based on the use of a buffer whose pressure is applied by a

piston pushed by the pressure of the fluid inside the

hydraulic circuit [6]. The pressure applied in any part of the

closed and incompressible fluid will be transmitted

uniformly in all directions throughout the fluid, that is, the

pressure of the entire fluid is constant. According to the

inference of physicist Pascal, the larger the size of the

element applying pressure, the greater the applied pressure,

the greater the force that can be obtained.

1.4 Expeller Pressing Process.

Continuous pressing is commonly performed in expeller or

screw presses. These presses support high pressures;

generally, pressing is practiced in two or three pressings,

increasing the pressure in each of them [7].

There are several types or models of presses, so the main

differences between these are the geometry of the screw, the

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type of orifice or nozzle, the oil outlet, and the residual filter

cake [8].

2. Materials and Methods.

2.1 Experimental Procedure for Avocado Oil Extraction

Using the Thermo-Batting Method.

The raw material was received and meticulously selected

based on the ripeness of the avocados, discarding fruits that

did not meet the desired hardness, firmness, texture, and

appearance criteria.

Next, the avocados were washed with distilled water to

eliminate any impurities that could alter the

physicochemical characteristics. They were then disinfected

with a 150 ppm bleach solution. The previously selected

fruit was weighed on a gravimetric balance, then peeled to

obtain the maximum amount of pulp. The seeds were

removed, the pulp was cut into pieces, and mashed with a

fork to facilitate placing the pulp into the drying trays for

optimal drying at 53°C for 24 hours. Once the pulp was

dried, it was broken into smaller pieces with a moisture

content of approximately greater than 5%, and fed into the

Piteba press hopper. The alcohol burner was lit and placed

on the equipment, allowing 10 minutes for the press to heat

up, which helped extract more oil from the raw material

used.

When the oil became too hot, the flame intensity was

reduced until it was appropriate. The pressure was applied

according to the regulator plug; the tighter the plug, the

higher the pressure. The expeller has two outlets: one for the

oil and one for the completely dried pulp in strip form. The

obtained product was filtered, its volume measured, bottled

in amber bottles, and stored at room temperature.

Table 1 describes the main materials, equipment, and

reagents used for avocado oil extraction from Hass variety

raw material using the Thermo-Batting Method.

Table 1. Materials, Instruments, and Equipment Used for Avocado Oil

Extraction by the Thermo-Batting Method.

Materials

Brand/Model

Capacity

Beakers

EISCO

250 ml

Glass jars

N/A

150 ml

Alcohol burner

N/A

50 ml

Filter paper

Whatman

150 mm Ø

Amber bottles

N/A

500 ml

Metal container

N/A

4 Lt

Instruments

Brand

Capacity

Gram scale

OHAUS

5 Kg

Oven

Dalvo/TDE/70

<= 200°C

Expeller press

Piteba

Reagents

Pureza

Bleach

75%

Distilled or deionized

water

100 %

ethyl alcohol

69.99 ° GL

Figure 1 shows the equipment used for the extraction of

avocado oil using the Thermo-Batting method.

Fig 1. Piteba Press, hot pressing with ethanol burner

2.2 Experimental Procedure for Avocado Oil Extraction

Using the Enzymatic Method.

After disinfecting the fruit as indicated in process 2.1, the

avocados were peeled and pitted. Then, 420 g of avocado

pulp was weighed. The obtained pulp was mashed in a metal

container, and the pH was adjusted to 5 using 42.5%

phosphoric acid and 7.7% ascorbic acid solutions. The

mixture was then transferred to a water bath on a stove, and

5 ml of the enzymatic preparation was added when the

temperature reached 40°C. The mixture was continuously

stirred for approximately 2 hours to facilitate the action of

the previously used enzymatic dose. The treated mixture

was placed in a hydraulic press, inside a poly-silk cloth and

a sieve, which allowed the oil and water to exit. The mixture

was manually pressed at 100 Kg/cm², and the resulting

liquid phase was centrifuged at 1400 rpm for 15 minutes to

separate the crude oil and water. The process was repeated

until a considerable amount of sample was obtained and

analyzed at the end of the process. The crude oil obtained

was neutralized, bleached, and dried using 200 g.

During neutralization, the free fatty acids that cause

instability or foaming tendencies at high temperatures were

removed. The oil was treated at 80°C with 5N NaOH to

form sodium salts. Then, 20 g of magnesium oxide was

added, allowed to react for 5 minutes at the specified

temperature with moderate and constant agitation.

For bleaching, undesirable compounds that give the oil a

bad appearance due to plant fibers and oxidative instability

due to chlorophyll were removed by filtering with 1%

diatomaceous earth. The mixture was then heated to 120°C

under a pressure of 130 mm Hg for 20 minutes in a vacuum

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oven. The earth was then discarded by vacuum filtration

using Whatman No. 4 filter paper.

Finally, for drying, a vacuum oven was used at 130 mm Hg

pressure and 120°C for 30 minutes. The oil sample was then

extracted into an amber bottle, labeled, and stored at room

temperature.

The materials, instruments, and equipment used for avocado

oil extraction by the enzymatic method are described in

Table 2.

Table 2. Materials, Instruments, and Equipment Used for Avocado Oil

Extraction by the Enzymatic Method.

Materials

Brand/Model

Capacity

Probeta

EISCO

50 ml

Poly-silk cloth

S/M

1 m

Amber bottles

S/M

500 ml

Metal container

S/M

4 Lt

Plastic test tubes with screw cap

Whatman No. 4 filter paper

BOECO

Germany

10 ml

Instruments

Brand

Capacity

Gram scale

OHAUS

5 kg

Single burner electric stove

IMACO

100°C

Hydraulic press

Century

20 ton

pH meter

OAKION

ecoTestr

0 – 14

Centrifuge (Washer)

Samsung

1400 rpm

Reagents

Purity

Bleach

75%

Distilled or deionized water

100 %

Pectinase enzyme (GranozymePTE

100)

Concentrada

Phosphoric acid

69,99 ° GL

Ascorbic acid

7,7%

Phosphoric acid

42,5%

Sodium hydroxide

5 N

2.3 Experimental Procedure for Avocado Oil Extraction

Using the Hydraulic Pressing Method.

After selecting, disinfecting, and weighing the avocados,

they were cut into pieces and mashed with a fork to facilitate

placing the pulp into the oven trays over polyethylene bags

for better drying at 53°C for 24 hours. Once the pulp was

dried, it was broken into smaller pieces with a moisture

content of approximately greater than 5% and fed into a

steel sieve connected to the hydraulic press. A flat container

was placed on the platens of the equipment and covered

with aluminum foil to collect all the oil, which was

channeled through a hose connected to a graduated cylinder

for sample collection.

A piece of poly-silk was then placed inside the sieve, and

pressure was applied by the press every 10 minutes,

reaching a force of 6000 lbs, until as much oil as possible

was extracted, leaving a dry cake.

The oil was passed through filter paper into a beaker and

then decanted over approximately 12 hours to ensure the

proper separation of oil from water and other

macroparticles. The obtained oil was deposited into 500 ml

amber bottles to prevent light from deteriorating the oil, and

the bottles were labeled for identification.

Finally, the bottles were stored at room temperature. Table

3 shows the materials, instruments, and reagents used in the

hydraulic pressing process.

Table 3. Materials, Instruments, and Equipment Used for Avocado Oil

Extraction by the Hydraulic Pressing Method.

Materials

Brand/Model

Capacity

Beakers

EISCO

250 mL

test tube

EISCO

100 mL

Poly-silk cloth

S/M

1 m

Amber bottles

S/M

500 mL

Aluminum foil

S/M

40 x 40 cm

Steel disc

S/M

8 -10 mm Ø

Polyethylene plastic bags

S/M

40 x 25 cm

Instruments

Brand

Capacity

Gram scale

OHAUS

5 Kg

Hydraulic press

Century

20 Ton

Stove

Dalvo/TDE/70

<= 200°C

Reagents

Purity

Bleach

75%

Distilled or deionized water

100%

Figure 2 shows the equipment used for the hydraulic

pressing process.

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Fig 2. Hydraulic press with a capacity of 20 tons used for the pressing

process

2.4 Experimental Procedure for Avocado Oil Extraction

Using the Expeller Press Method

The current method followed the process of selecting and

disinfecting the raw material as in the other procedures

mentioned earlier. Subsequently, the pulp was cut into

pieces and mashed with a fork to facilitate placing the pulp

into oven trays for optimal drying at a temperature of 53°C

for 24 hours. Once the dried pulp was obtained, it was

fragmented into smaller pieces with a moisture content of

approximately greater than 5% and fed into the hopper of

the Piteba press.

The pressure applied was adjusted according to the

regulating plug; tightening this plug increased the pressure.

It should be noted that the expeller has two outlets: one for

the oil and the other for the completely dried pulp in strip

form.

After obtaining the oil, the process was repeated for

filtering, measuring, bottling in amber bottles, labeling, and

storing, similar to the Thermo-Batting method. It is

important to emphasize that unlike the Thermo-Batting

process, the expeller press was not heated to obtain the oil.

Table 4 lists the materials, instruments, and reagents used

for the expeller press method of avocado oil extraction.

Table 4. Materials, Instruments, and Equipment Used for Avocado Oil

Extraction by the Expeller Press Method.

Materials

Brand/Model

Capacity

Precipitation beakers

EISCO

250 ml

Glass jars

S/M

150 ml

Filter paper

Whatman

150 mm Ø

Amber bottles

S/M

500 ml

Metal container

S/M

4 Lt

Instrument

Brand

Capacity

Gram scale

OHAUS

5 Kg

Stove

Dalvo/TDE/70

<= 200°C

Expeller press

Piteba

Reagents

Purity

Bleach

75%

Distilled or deionized water

100 %

2.5 Yield Determination.

To determine the yield, corresponding measurements were

taken for each extraction method in relation to the weight of

oil obtained on a dry basis. The yield percentage on a dry

basis was calculated using the weight of the dry matter of

the pulp employed.

To obtain the percentage yield values on a dry basis for each

method, the following equation (1) was applied, considering

the Moisture Percentage of Hass Avocado Pulp (Gutarra

Sanabria & Vargas Rodríguez, 2018):

󰇛󰇜  

󰇛󰇜

󰇛󰇜

  (1)

2.6 Determination of physicochemical characteristics.

For the evaluation of physicochemical variables, four

samples obtained from each extraction method were

analyzed for six parameters: acidity index, peroxide value,

saponification value, iodine value, density, and moisture.

These parameters were compared using a bibliographic

reference, a commercially available oil with similar

characteristics, and the NTE INEN 29 standard for olive oil,

as there is no specific INEN standard for avocado oils.

a) Acidity Index

The AOAC 21TH 2019,940.28 standard was referenced for

this technique, which was developed by AVVE

Laboratories S.A. and expressed in units of g/100g.

b) Peroxide Value

This test was based on the AOAC 21TH 2019,965.33

standard, conducted at AVVE Laboratories S.A., with

measurements in mEqO2/kg.

c) Saponification Value

The methodology used for this parameter was based on the

MMQ-87 AOAC 21TH 2019,920.160 standard, developed

by AVVE Laboratories S.A., with units in mg KOH/g.

d) Iodine Value

La técnica que se aplicará para este método de ensayo se la

realizó de acuerdo a la Norma MMQ-87 AOAC 21TH

2019,920.159, desarrollada en los Laboratorios AVVE.

S.A., y sus unidades se expresarán en cg/g.

e) Density

To determine density, an empty and dry graduated cylinder

was weighed and tared on a balance. Immediately, it was

filled with 100 mL of the sample, and the weight was

recorded. Density was calculated using the following

formula:

ρ=m/V (2)

Where ρ is the density in g/mL, m is the mass in grams, and

V is the volume in mL. The procedure was repeated for each

sample of oil obtained from each different method.

f) Moisture

This test was conducted according to the NTE INEN 39

standard, which specifies the Determination of Loss on

Heating (Moisture) and Other Volatile Matters in animal or

vegetable fats and oils.

For the determination of moisture, the sample was checked

to ensure it was liquid, clear in appearance, and free of

sediment. It was then inverted several times in its container.

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Subsequently, 5 g of the sample was placed in a pre-

weighed porcelain dish, which was then placed in an oven

heated to 103°C ± 2°C. After heating, the dish was cooled

in a desiccator and weighed. These operations were repeated

for each sample obtained from each extraction method. The

moisture content was calculated using the following

formula:

 













(3)

Where 



represents the initial weight and 



the final

weight.

Table 5 lists the materials, instruments, and reagents used

for the determination of density and moisture.

Table 5 Materials, instruments, and reagents used for the determination of

density and moisture of avocado oil.

Materials

Brand/Model

Capacity

Graduated cylinder

Glassco

100 mL

Porcelain capsules

Canfort

Instrumentos

Brand/Model

Capacity

Gram scale

Ohaus

2 Kg

Silica gel desiccator

S/M

Oven

Dalvo/TDE/70

<= 200°C

Reagents

Purity

Avocado oil

100%

2.7 Fatty Acid Profile Determination.

The fatty acids of the oils obtained through the four

extraction methods were determined using High-

Performance Liquid Chromatography (HPLC), following

Standard MMQ-HPCL-09, conducted at AVVE

Laboratories S.A. These results were compared with a

bibliographic reference and the analysis of a commercial oil.

3. Results

3.1 Yield

The yield values obtained for each extraction method are

shown in Table 6.

Table 6. Yield values obtained for each extraction method

The yield percentage by extraction method:

Termobatido

Enzymatic

Hydraulic

pressing

Expeller

pressing

89.78

6.79

7.57

38.98

In Figure 3, the yield percentages by extraction method are

shown.

Fig 3. Bar chart comparing yield percentages among extraction methods.

3.2 Results of physicochemical characteristics

able 7 shows the results of the determination of

physicochemical characteristics of avocado oil obtained by

the 4 processes.

T able 7 Physicochemical Characteristics of avocado oil for each extraction

method.

Physicochemica

l Analysis

Extraction Methods

Units

Acidity Index

3.13

1.29

0.90

5.05

g/100g

Peroxide Index

78.87

11.36

4.32

49.57

mEqO2/k

Saponification

Index

190.0

189.2

193.8

193.4

mKOH/m

Iodine Index

84.56

78.25

74.29

84.49

cg/g

Density

0.903

0.895

0.900

g/ml

Moisture

0.054

0.048

0.044

0.052

A: Thermo-mechanical Method, B: Enzymatic Method, C: Hydraulic

Pressing Method, D: Expeller Pressing Method

Figure 4 shows a comparison via bar chart of the Physical

Characteristics of oil obtained through different extraction

methods.

Figure 4: Comparison Chart of Physical Characteristics of oil among

extraction methods.

Figure 5 displays the chemical characteristics obtained from

the oil corresponding to each extraction method.

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Fig 5 Comparison Diagram of Chemical Characteristics of Oil Obtained by

Extraction Methods.

Table 8 Physicochemical Parameters from Bibliographic

References for Respective Comparison.

Table 8 Physicochemical Characteristics of Avocado Oil Obtained by

Thermo-mechanical Extraction, Rapid Evaporation, and Pressing.

Physicochemical

Characteristics

Extraction Method

Units

Termo-

mechanical

Extraction

Rapid

Evaporation

and

Pressing

Acidity Index

0,38

0,10

g/100g

Peroxide Index

5,56

2,20

mEqO

/kg

Saponification

Index

195,55

130,00

mKOH/mg

Iodine Index

80,94

69,91

cg/g

[9].

[10]

3.3 Fatty Acid Profile Results of the Oils Obtained.

Table 9 shows the fatty acid profile results of the oils

obtained through the processes of Thermobatido,

Enzymatic, and Hydraulic pressing, while Table 10 presents

the fatty acid profile results of the oil obtained through the

expeller pressing process, the lipid profile of a bibliographic

reference, and that of a commercial oil branded MIRA.

Table 9 Fatty Acid Profile Results of Avocado Oil Obtained by

Thermobatido, Enzymatic, and Hydraulic Pressing Processes.

Lipid Profile of

Fatty Acids

Extraction Methods

Units

Termobati

Enzimáti

Hydraulic

pressing

Saturated Fatty

Acids

17,93

17,12

23,57

g/100g

Monounsaturated

Fatty Acids

71,38

72,23

64,29

g/100g

Polyunsaturated

Fatty Acids

10,69

10,65

12,14

g/100g

Linolenic Acid

(Omega 3)

0,76

0,66

0,48

g/100g

Linoleic Acid

(Omega 6)

9,93

9,99

11,65

g/100g

Oleic Acid

(Omega 9)

67,03

67,02

61,07

g/100g

Palmitic Acid

17,23

14,93

21,00

g/100g

Stearic Acid

0,51

1,05

1,26

g/100g

Vitamin E

mg/100g

Table 10 Fatty Acid Profile Results of Avocado Oil Obtained by Expeller

Pressing Process, Thermomechanical Extraction, and Commercial Oil

Brand MIRA.

Lipid Fatty Acid

Profile

Extraction Methods

Units

Expeller

Pressing

Mechanical

Extraction

MIRA

brand

Avocado

Oil

Saturated Fatty

Acids

18,68

22,1059

21,3

g/100g

Monounsaturated

Fatty Acids

69,99

63,7555

78,7

g/100g

Polyunsaturated

Fatty Acids

11,33

13,6216

g/100g

Linolenic Acid

(Omega 3)

0,91

0,7599

1,4

g/100g

Linoleic Acid

(Omega 6)

10,41

12,8726

8,9

g/100g

Oleic Acid

(Omega 9)

65,72

53,2511

56,62

g/100g

Palmitic Acid

17,73

21,5194

g/100g

Stearic Acid

0,57

0,4806

g/100g

Vitamin E

10,11

13,28

mg/100g

4. Discussion

4.1 Yield Analysis

Once the yield percentages for each extraction method were

calculated, it was determined that the highest percentage

was achieved by the Termobatido method with 89.78%,

followed by the Expeller Pressing method with 39.98%.

Consequently, Hydraulic Pressing yielded 7.57% and the

Enzymatic method 6.79%. Therefore, it is established that

the Termobatido method yielded the best results in terms of

yield.

Regarding the Termobatido method, it applies high-

temperature pressure, which helps to break down more oil

particles. However, a disadvantage is its appearance, as it

results in oil with a darker hue compared to the other

methods.

4.2 Analysis of Physicochemical Characteristics

In the research by Candori Cahui [10] it is noted that

"Physicochemical properties are the most common indices

for evaluating the quality of seed oils in the food industry.

However, determinations of the physicochemical properties

of vegetable oil are necessary to judge the suitability of oil

for a particular application."

Therefore, these characteristics allow identifying if the oils

are in the appropriate state for subsequent quality testing, or

if they should be rejected if their quality is not adequate.

Regarding the physical characteristics developed in this

research, the values of moisture (Loss on Heating) and

relative density achieved results that are in accordance with

the NTE INEN 29 [11], standard, which is similar to the

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Pag. 56

products obtained in this project, such as Olive Oil. The

standard specifies a maximum of 0.050% for moisture and

a range of 0.840 to 0.960 g/ml for relative density.

According to the data obtained, the Termobatido,

Enzymatic, and Hydraulic Pressing methods show acidity

index values established by the NTE INEN 29 [11] between

0.8 and 3.3 g/100 g. Regarding the peroxide index, only the

Hydraulic Pressing method shows a value below 10

mEqO2/kg according to the mentioned standard.

Comparing the iodine index with the NTE INEN 29 [11]

which indicates values between 79 and 89 cg/g, all four

extraction methods comply with the comparison standard.

4.3 Analysis of Fatty Acid Profile Results

According to the analyses and comparisons of results

regarding the main fatty acids - Oleic (C18:1), Linoleic

(C18:2), Alpha Linolenic (C18:3), Palmitic (C18:0), and

Stearic (C18:0) acids - tabulated, it can be observed that the

Termobatido method performs better in terms of oleic acid

percentage. This is due to the sensitivity of oleic acid to

heat, where products with higher proportions of unsaturated

fatty acids are more prone to oxidation compared to those

with smaller amounts.

Regarding Linoleic Acid, the Enzymatic method shows the

highest percentage, similar to the value obtained by Yepes

Betancur [9].

Concerning Alpha Linolenic Acid, the Expeller method

resulted in the highest percentage. Subsequently, for

Palmitic Acid, which is a saturated acid, the Enzymatic

method is better due to its lower percentage, unlike the other

techniques with higher saturation due to exposure to

pressure and temperature treatments. [12]

Bergh [13] Concerning Alpha Linolenic Acid, the Expeller

method resulted in the highest percentage. Subsequently,

for Palmitic Acid, which is a saturated acid, the Enzymatic

method is better due to its lower percentage, unlike the other

techniques with higher saturation due to exposure to

pressure and temperature treatments.

In contrast, Stanley [14], states that without neglecting the

importance of unsaturated fatty acids such as oleic and

linoleic acids, these are hypocholesterolemic, thus

decreasing LDL cholesterol concentrations deposited in

arteries and enhancing beneficial actions of HDL

cholesterol.

For these reasons, oils extracted by different methods such

as Termobatido, Enzymatic, Hydraulic Pressing, and

Expeller comply with nutritional requirements, thereby

contributing to consumer health. It is noted that their results

exhibit some similarities in relation to the analyzed fatty

acids.

The minimal differences found in this study regarding

physicochemical properties and fatty acid composition of

avocado oil are likely due to extraction techniques,

environmental conditions of the fruit, its variety, or maturity

state.

5. Conclusions

The extraction of Hass Avocado oil using four methods

allowed for the evaluation and verification of differences

and similarities in both the execution of techniques and

results. Subsequently, the best process that offers the best

quality conditions can be selected for implementation at the

pilot plant level and finally at the industrial level with

properly tested process and operation conditions until

optimization is achieved.

Significant differences were found in terms of yield, with

the Termobatido method yielding the highest percentage at

89.78%, and the Enzymatic method yielding the lowest at

6.79%. Comparing the four extraction methods, it is

concluded that the Hydraulic Pressing process presents the

highest values concerning the content of saturated fatty

acids, polyunsaturated fatty acids, linoleic acid, palmitic

acid, and stearic acid, respectively.

Considering the process yield, which is important in terms

of productivity, as well as the quality of the product

obtained in relation to its physicochemical properties and

fatty acid profile, it is concluded that quality is related to a

low yield of oil obtained. The Hydraulic Pressing process

presents the best product quality conditions but with a

relatively low yield (7.57%). If the objective of an industrial

plant is to achieve high yield, the most suitable method

would be Termobatido, albeit with a decrease in oil quality,

particularly concerning physical properties rather than the

fatty acid profile, which provides a beneficial contribution,

especially from unsaturated fatty acids for health.

Given that the yield in the Termobatido process is the

highest, it is recommended to study its implementation

using antioxidants to reduce the peroxide index related to

oil oxidation.

6. Referencias

]

R. Melo, «El Telégrafo,» 20 Febrero 2016. [En línea]. Available:

https://www.eltelegrafo.com.ec/noticias/regional/1/los-cultivos-de-

aguacate-se-extienden-por-los-valles-templados-de-la-serrania.

[Último acceso: 27 Abril 2020].

]

«El Comercio,» 3 Febrero 2019. [En línea]. Available:

https://www.elcomercio.com/tendencias/consumo-aguacate-ecuador-

precolombino-intercultural.html. [Último acceso: 27 Abril 2020].

]

D. A. Cueva Cabrera y A. S. Pilatuña Zambrano, «Universidad

Politécnica Salesiana,» Septiembre 2016. [En línea]. Available:

https://dspace.ups.edu.ec/bitstream/123456789/7102/1/UPS-

QT05876.pdf.

]

J. M. Rincón Martínez y E. E. Silva Lora, «Bioenergía: Fuentes,

conversión y sustentabilidad,» 1 ed., ISBN, Ed., Bogotá, Cyted, p.

332.

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Pag. 57

]

L. Rodríguez, «Universidad Nacional del Sur,» Mayo 2019. [En

línea]. Available:

http://repositoriodigital.uns.edu.ar/bitstream/123456789/4550/1/TES

IS%20DOCTORAL-RODRIGUEZ%20LUCIANA-2019.pdf.

]

S. Shourkroun, «Organización y gestión de las operacionesde

conformadoy secado de productos cerámicos,» 5.1 ed., Elearning

S.L., 2015, pp. 137 - 359.

]

A. E. Bailey, «Aceites y Grasas Industriales,» 2 ed., Reverté, 1944,

p. 746.

]

P. Beerens, «Screw-pressing of Jatropha seeds for fuelling,» D. o. S.

E. Technology, Ed., Eindhoven University of Technology, 2007.

]

D. P. Yépes Betancur, L. Sánchez Giraldo y C. J. Marquéz Cardozo,

«Extracción termomecánica y caracterización fisicoquímica del

aceite de aguacate (Persea americana Mill. cv. Hass),» Informador

Técnico (Colombia), vol. 81, nº 1, pp. 75 - 85, 28 Junio 2017.

M. Candori Cahui, «Análisis de extracción de aceite de palta (Persea

americana) de la variedad Fuerte por evaporación rápida de agua.,»

Diciembre 2016. [En línea]. Available:

https://repositorio.upeu.edu.pe/bitstream/handle/UPEU/410/Moises_

Tesis_bachiller_2017.pdf?sequence=1&isAllowed=y.

INEN, «Servicio Ecuatoriano de Normalización,» 2012. [En línea].

Available: https://www.normalizacion.gob.ec/buzon/normas/29.pdf.

H. D. Gutarra Sanabria y M. F. Vargas Rodríguez, «Universidad de

San Ignacio de Loyola,» Junio 2018. [En línea]. Available:

http://repositorio.usil.edu.pe/bitstream/USIL/3252/1/2018_Gutarra-

Sanabria.pdf.

B. Bergh, «The avocado an human nutrition. Avocados and your

heart. Proceedings of the second world avocado congress.,» 1992.

[En línea].

J. C. Stanley, «The nutritional reputation of palm oil,» Lipid

Technology, vol. 20, nº 5, pp. 112-114, Abril 2018.