EP2009085A1

EP2009085A1 - Use of calcium carbonate as technological coadjuvant in oil and fat extraction processes

Info

Publication number: EP2009085A1
Application number: EP07730513A
Authority: EP
Inventors: Manuel Moya Vilar; Diego Gines FERNÁNDEZ VALDIVIA; Marco Antonio DÍAZ RODRÍGUEZ; Francisco Espinola Lozano
Original assignee: Minera Del Santo Angel SL
Current assignee: Minera Del Santo Angel SL
Priority date: 2006-04-19
Filing date: 2007-04-16
Publication date: 2008-12-31
Anticipated expiration: 2027-04-16
Also published as: WO2007118920A1; TNSN08395A1; EP2009085B1; PT2009085T; ES2586393T3; ES2284390B1; MA30414B1; ES2284390A1; EP2009085A4

Abstract

The present invention relates to the use of calcium carbonate as technological coadjuvant in oil and fat extraction processes, more specifically for virgin olive oil.

Description

FIELD OF THE INVENTION

The present invention relates to the use of calcium carbonate as technological coadjuvant in oil and fat extraction processes, more specifically virgin olive oil.

BACKGROUND OF THE INVENTION

Between 98% and 99% of the oil contained in olives is constituted by triglycerides which are accumulated in the mesocarp cells, in the vacuoles and, in smaller quantity it is dispersed in the cytoplasm.
In the extraction operation to produce quality olive oil it is necessary to take care of many details, an essential condition for its extraction is that it is done by physical-mechanical methods and in conditions, especially thermal, which do not produce any alteration. In these terms, the European legislation defines virgin olive oils as "oils obtained from the fruit of the olive tree solely by mechanical or other physical means under conditions that do not lead to alterations in the oil, which have not undergone any treatment other than washing, decanting, centrifuging and filtration, to the exclusion of oils obtained using solvents or using adjuvants having a chemical or biochemical action, or by re-esterification process and any mixture with oils of other kinds" (Appendix to EC Regulation 1513/2001).
Quality oils are obtained when starting from whole olives, healthy and with an ideal state of maturation, they are processed as fast as possible, due to the fact that storage or "atrojado" (fusty) unleashes fermentative processes on the fruit. The grinding or crushing operation has the objective of breaking the cells of the pulp, mesocarp, and causing the exit of the oil contained in the vacuoles. Until 1960, the oil technology had only used roller mills, but today hammer mills are used whereby a high degree of efficacy can be achieved in cell rupture, although they cause emulsions in the paste on rotating at high revolutions (3000 rpm).
The industrial fat yield is related to the degree of milling, regulated in the hammer mill by the diameter of the perforations of the screen or grille (mesh opening). In general, and depending on the variety of olive milled the mesh opening may increase the maturity index of the olive.
The oil released mechanically should abandon the cell tissues in the form of small drops which, in turn, may give rise to larger drops until forming bags which may be separated as a continuous phase. This stage is carried out in a thermomixer, within very strict temperature limits so as not to favour the loss of volatile products, responsible for the oil aroma, and that oxidation and going stale processes do not start. The virgin olive oil is considered as the oily juice of a fruit, olive, and with a good preparation they must be maintained without altering their aroma, taste and the minority components that characterize them.
The temperature and duration of the mixing gives as a result the increase in oil yield in the extraction, whatever the extraction system: pressing, centrifugation or percolation. However, said increase in temperature and mixing time have a negative effect on the quality and content of antioxidants and vitamins in virgin olive oils (Hermoso et al., 1998)
In an industrial process, the yield of the extraction ranges from 80% to 90% of the total oil as it does not release all the oil present in the olives, there is some left in the cells which have not broken, in the colloidal system of the olive paste (microgels) and bound in the form of emulsion with the vegetation water. The difficulty of releasing this oil lies in the fact that the drops of dispersed or emulsified oil are surrounded by a lipoprotein membrane (phospholipids and proteins) which keep them in that state, hindering the bonding thereof (Boskou, 1998).
To produce a good quality oil, both from the nutritional and organoleptic point of view, it is necessary to:

a) Start from healthy and whole fruit, preferably collected from the tree
b) Optimum state of maturation and humidity, to avoid the addition of water to the process.
c) Processing the recently collected olives in a period of no more than 24 hours.
d) Breaking the majority of the cells avoiding the formation of emulsions.
e) Mixing the paste at a moderate temperature and without extending the mixing time excessively.

Any professional of an olive oil mill knows that in the aforementioned operating conditions the industrial yield may drop, on many occasions, between 10 and 20% of the fat content. They may easily lose between 2 and 4 kg of oil per 100 kg of olives when the so-called "difficult pastes" or emulsified pastes appear.
Technological coadjuvants are used, in extraction, with the objective of recovering the majority of the oil retained by the pastes. These substances are usually added in the thermomixer and help to correct the cell structure, modify the physicomechanical properties of the pastes and facilitate the separation of the oil. In Spain, since 1986 (Order of 13 January 1986 of the Ministry of Health and Consumer Affairs) hydrated magnesium silicate has been used (natural talc) and since 1989 (Order of the Ministry of Health and Consumer Affairs) carbohydrase (pectinases, cellulases and hemicellulases) from Aspergillus aculeatus. However, European legislation prohibits, as previously indicated, the use of biologically active technological coadjuvants in preparing virgin olive oils, there not being any alternatives to the use of talc as technological coadjuvant for the extraction of virgin and extra virgin olive oil.
The temperature increase and duration of the mixing gives as a result the increase in oil yield in the extraction, however, said increase has a negative affect on the quality of the virgin olive oils. Therefore, another relevant characteristic for the technological coadjuvants is that with their use greater or similar extraction yields are produced to those produced with the temperature increase, but maintaining oil quality. This circumstance makes it even more difficult, if possible, obtaining alternative substances which can be used in these processes.

BRIEF DEFINITION OF THE INVENTION

DEFINITIONS:

Technological coadjuvant: any substance which is not consumed as a food ingredient in itself, which is intentionally used in the transformation of raw materials, of food products or of their ingredients, to meet a certain technological objective during the treatment or the transformation, and which may have as a result the unintentional, but technically unavoidable, presence of residues of said substance or of its derivatives in the finished product, provided that said residues do not have any health risks and do not have technological effects on the finished product (Royal Decree 3177/1983, of 16 November)
The present invention provides a new technological coadjuvant, calcium carbonate and/or limestone, in oil and fat extraction processes.
Understanding that calcium carbonate is authorized as food additive, and due to its high specific weight (2.72 g/cm³), which makes it easily eliminable by centrifugation, studies have been carried out for the use of calcium carbonate (CAS no. 471-34-1; EINECS 207-439-9) and of limestone (CAS No. 1371-65-3; EINECS 215-279-6) as technological coadjuvants in the oil and fat extraction processes, even more preferably olive oil, and yet even more preferably virgin and or extra virgin olive oil.
Finally, the characteristics of the oils obtained with the use of the coadjuvant have been analysed, verifying that all of them meet the quality specifications regulated by the European Union, which would grant them the classification of "extra virgin olive oil" and that there are no statistically significant differences between the oils produced with or without coadjuvant (controls).
Thus, a first aspect of the present invention is related to the use of a compound which comprises calcium carbonate as technological coadjuvant, preferably in the food industry, more preferably in oil and fat extraction processes, more preferably vegetable oils, even more preferably olive oil, and yet even more preferably virgin or extra virgin olive oil. In a preferred embodiment of this aspect of the invention the technological coadjuvant is limestone. Hereinafter this compound will be called "compound of the invention".
In a second embodiment of the first aspect of the invention, the compound of the invention comprises a richness of calcium carbonate of al least 90%, successively and more preferably of at least 95, 98, 99% and even more preferably 99.28%.
In a third embodiment of the invention and according to the second embodiment of the invention, the compound of the invention has a humidity of less than 5%, more preferably of less than 3% and even more preferably less than 1%.
In a fourth embodiment of the invention and according to any of the previous embodiments, the compound of the invention has a maximum particle diameter of 55 µm, more preferably less than 44 µm; more preferably between 10-0.1 µm and in successively more preferred embodiments between 5-1 µm, 4-1.5 µm, 3.5-2 µm, 3-2.5 µm, and even more preferred an average diameter of 2.65 µm.
In a fifth embodiment of the invention and according to any of the previous embodiments, the compound of the invention is used in doses of at least 0.01%, in successively more preferred embodiments of between 0.01-30%, 0.1-20%, 0.5-10%, 1-5% and even more preferably of 1% or 3%.

BRIEF DESCRIPTION OF THE FIGURES

FIG 1 : Variation of the extraction yield according to the variety of olive and the percentage of calcium carbonate added.
FIG 2 : Variation of extraction yield due to the addition of calcium carbonate.
FIG 3 : Graphic of interaction of the extraction yield compared with the dose of carbonate for two temperatures.
FIG 4 : Graphic of interaction of the extraction yield against the temperature.
FIG 5 : Response surface for the yield maintaining the temperature constant at 30°C.
FIG 6 : Variation in the extraction yield according to the variety of olive and the percentages of calcium carbonate and talc used.
FIG 7 : Granulometric analysis of the calcium carbonate used in the tests.

DETAILED EXPLANATION OF THE INVENTION

The efficacy of the technological coadjuvant proposed (calcium carbonate and limestone) has been evaluated in the laboratory using the Abencor yield analyzer for three important varieties of olives: Picual, Hojiblanca and Arbequina, with different maturity indices.
The results obtained in the test reveal that the use of micronized calcium carbonate makes it possible to increase the extraction yields to 4.51 kg of olives per 100 kg of olives in the Picual, 4.37 kg of oil per 100 kg of olives in the Hojiblanca variety and 2.63 kg of oil per 100 kg of olives from the Arbequina variety, with respect to the tests carried out without the use of coadjuvants, said quantity depending on the variety, maturity index and humidity of the olives, their efficacy being greater in the treatment of emulsified pastes, also called "difficult pastes".
The following examples of embodiment of the invention do not aim to be limitative thereof and only illustrate it for its better understanding.

EXAMPLES OF EMBODIMENT

Example 1. Calcium carbonate used

The physicochemical characteristics of the calcium carbonate used to perform the following examples of embodiment are shown below:

Richness of calcium carbonate 99.28%
pH 8.2
Specific weight 2.72 g/cm³
Hardness 3
Apparent density 1.20 g/cm³
Specific surface area 5.8 m²/g

The following table shows other technical characteristics of the calcium carbonate used and FIG 7 shows a graphic representing its granulometry.

PHYSICAL CHARACTERISTICS	TEST RESULTS TOLERATED
Granulometry	Rejections at 44 µm < 0.1 %
	% less than 1.95 µm 41.2 = 7%
	Average diameter 2.65 = 0.5 µm
Whiteness (dry)	L: 94.4 ± 1.0 a: 0.3 ± 1.5 b*: 3.4 ± 0.6
Humidity	<1.0 %
Apparent density	1.20 ± 0.2 g/cc

The tests have been carried out with samples of olives (Olea europea L.) of three varieties: Picual, Hojiblanca and Arbequina, the first from Jaén and the other two from Gilena (Seville). All the samples have been characterized by determination of the maturity index (Uceda and Frias, 1975), the humidity and volatile materials in an oven at 105°C and the oil content according to the Soxhlet method (Regulation EEC 2568/91). The results are shown in the following table (Table 1).

TABLE 1. Characterization of the samples of olives

Variety of olive	Maturity Index	Humidity and volatile materials %	Oil %	Solids %
Picual
1	3.2	48.86	19.90	31.24
Picual 2	3.8	42.26	22.56	35.18
Picual 3	5.5	43.35	23.06	33.59
Picual 4	5.6	44.25	28.89	26.87
Hojiblanca	4.9	42.30	27.13	30.57
Arbequina	4.5	44.64	29.24	26.13

The data correspond to average values of three replicas.

Example 3. Oil extraction and yield

The oils have been extracted using the Abencor yield analyzer. This apparatus consists, essentially, of three basic elements to simulate, in the laboratory, the industrial virgin olive oil production process: Hammer mill, thermomixer and solids centrifuge, and a series of auxiliary elements (Mártinez et al., 1975).
The general working conditions are detailed below, whilst the water temperature of the mixer and the mixing time are specified in each section of experimental results:

>Diameter of the mill screen: 5.5 mm
> Mixed olive mass: 500 g
> Centrifugation time: 1 min.
> Addition of hot water (≈ 50 °C) for drag: 100 mL.
> Centrifugation time with the added water: 1 min.

After centrifugation, the oil obtained has been decanted in a test tube during, at least, 3 hours, it has been filtered with filter paper and stored at 4°C in a N₂ atmosphere until its analysis.
A sample of the olive pomace that remains in the centrifuge has also been taken to determine the quantity of oil retained in it, by the Soxhlet method, and be able to evaluate by difference with the initial oil, present in the olives, the extraction yield (kg of oil per 100 kg of olives processed). This method has been chosen instead of determining the yield by volume of oil obtained as it is more precise, since the gravimetric measurements are performed with greater precision than the volumetric ones.
Several experimental designs have been carried out which range from the simple comparison of yields with the use or not of carbonate to the variation in the dose thereof in order to determine the optimum dose. Complete 2² factorial designs have also been carried out and those of response surfaces, Box-Behnken, to jointly evaluate the addition of carbonate, the temperature and the mixing time of the olive paste (Montgomery, D.C. Diseño y Análisis de Experimentos. Limusa Wiley. Mexico, 2002.)
In all cases, a statistical processing of the results has been performed, using for the variance analysis (ANOVA) the statistical package Statgraphics Plus 5.1 of Statistical Graphics Corp., Rockville, MD, USA, and for the statistical design of experiments the computer program Design-Expert version 6.0.6 from Stat-Ease Inc., Minneapolis, USA.

Example 3. Efficacy of the carbonate

Isolated tests have been carried out on the calcium carbonate using doses of 1% and 2%. Table 2 shows the results obtained for the samples of Picual, Hojiblanca and Arbequina olives, mixing in all cases the olive paste at 30°C (water temperature of the thermomixer) for 55 minutes.

Likewise, Table 2 shows the values of the statistical parameter p resulting from the ANOVA ns the result of applying the less significant differences procedure of Fisher (LSD).

TABLE 2. Yields (kg of oil/ 100 kg of olives)

Carbonate added	Picual 1	Picual 2	Hojiblanca	Arbequina
0% (Control)	15.38 ± 0.29^a	18.55 ± 0.13^a	19.55 ± 0.55^a	22.33 ± 0.36^a
1%	16.66 ± 0.18^b	19.53 ± 0.08^b	22.16 ± 0.22^b	24.71 ± 0.19^b
2%	16.75 ± 0.10^b	19.33 ± 0.10^b	23.28 ± 0.52^b	24.89 ± 0.49^b
ANOVA	p < 0.04	p < 0.02	p < 0.03	p < 0.03

Average value ± standard error:
The same letter as superscript in a column indicates that there are no significant differences between them for a confidence level of 95%.

From Table 2 it is gathered that the use of calcium carbonate improves the extraction yield by 1.37 points (kg oil / 100 kg of olives) for the Picual sample 1; by 0.98 points for the Picual sample 2; by 3.73 points for the Hojiblanca sample (which means an increase of 19% of the yield); and 2.56 points for the Arbequina sample.
The yield difference observed between the Picual 1 and Picual 2 samples is related to the increase in the maturity index. The increase in said index reduces the need to use the coadjuvant, or rather, this is especially useful for olives with low maturity index, start of the season, and for those that produce difficult pastes, such as, for example, frozen olives.
The details from Table 2 have been represented in Figure 1 and, in it, the increase in extraction yield obtained is graphically observed, in all cases, due to the addition of calcium carbonate.

Example 3.2: Determination of the recommended dose

Two series of experiments have been carried out with Picual and Arbequina olives to determine the most appropriate dose of use of calcium carbonate.

Table 3 shows the yield details for the Picual 4 and Arbequina samples. The mixing of the olive paste has been performed at 30°C (water temperature of the thermomixer) during 55 minutes.

TABLE 3. Yields (kg oil/ 100 kg olives) for different doses of carbonate added

Carbonate added %	Picual 4	Arbequina
0.0	18.73	22.33
0.1	--	22.88
0.25	--	23.79
0.5	22.23	24.52
1.0	23.21	24.71
1.5	--	25.25
2.0	23.26	24.89
3.0	22.94	--
4.0	23.31	24.52
8.0	23.05	24.34

The values of Table 3 have been represented in Figure 2 by dots, observing, in both cases, that the extraction yield increases with the percentage of calcium carbonate added, until reaching a maximum value after which it seems that there is a small decrease in yield, certainly due to the oil which is retained in the carbonate.
The details from Table 3 have been adjusted, by non-linear regression with the program SigmaPlot 9 from Systat Software Inc, to the following equations, where R is the yield (kg of oil/ 100 kg of olives) and C is the dose of calcium carbonate added (%).

For the Picual variety: $R = 18.73 + \frac{5.0805 C}{0.1881 + C} - 0.0856 C$

For the Arbequina variety: $R = 22.33 + \frac{3.5129 C}{0.3305 + C} - 0.1854 C$
The above equations have been used to represent the continuous lines of Figure 2, observing a good fit, and to determine the optimum addition value of calcium carbonate.
For the Picual variety, the optimum dose of addition of carbonate is 3.1%, which would give a maximum oil yield of 23.24%, i.e. 4.51 kg of oil more per 100 kg of olives compared with the non-use of carbonate (24.1 % increase).
For the Arbequina variety, the optimum dose of addition of carbonate is 2.1%, which would give a maximum oil yield of 24.96%, i.e. 2.63 kg of oil per 100 kg of olives compared with the non-use of carbonate (12.18 increase).
Nevertheless, as can be observed in Figure 2, these maximums are not very marked and for this reason there is a wide range of variation in the dose of calcium carbonate added without this appreciably weakening the extraction yield.

Example 3.3. Combined study of the dose of carbonate and the mixing temperature.

In order to simultaneously find out which effect the mixing temperature has on the paste and the dose of carbonate used, and to check if both factors interact with one another, a complete 2² factorial design has been performed with the sample of Picual 3 olives. Table 4 shows the experimental design and the yields produced, maintaining the general experimental conditions and mixing the olive paste in all cases during 20 minutes. TABLE 4 Experimental design and yields

Factors Response

Execution order Temperature °C Carbonate added, % Yield, %

4 20 0 16.06

3 40 0 17.11

1 20 1 17.96

2 40 1 18.20

In light of the results the following information is obtained:

a) Average value: (16.06+17.11+17.96+18.20)/ 4= 17.33%
b) Effect of temperature: (-16.06+17.11-17.96+18.20)/2 = 0.64%
c) Effect of carbonate: (-16.06-17.11+17.96+18.20)/2 = 1.49%
d) Effect of interaction(16.06-17.11-17.96+18.20)/2 = -0.40%

In first place, it has been verified that the variation observed in the yield is due to a real effect of each factor and not to the experimental error; for said purpose, three replicas of one point have been made, obtaining a standard deviation of 0.25 and a standard error of 0.15. Then, we can accept that all effects have statistical significance.
The addition of carbonate has greater effect than the temperature increase, since an addition of carbonate of 1% makes the yield increase by 1.49 points (9.3% of increase in yield), whilst the temperature increase from 20°C to 40°C only makes the yield increase by 0.64 points. This conclusion is very interesting as better quality oils are obtained working at low temperature.
On the other hand, we observe a small interaction effect between the temperature and the carbonate added, -0.40%, as shown in figures 3 and 4 of the interaction graphics.
In the interaction graphics it is observed that the lines are not parallel, then the effect of the temperature is greater for a concentration of 0% of carbonate than for a 1% concentration of carbonate, and the effect of the addition of carbonate is greater at a low temperature, 20°C, than at a high temperature, 40°C.

Example 3.4. Combined study of the dose of carbonate and the mixing time

Similarly to above, a complete 2² factorial design was carried out on the sample of Picual 3 olives to simultaneously find out the effects of stirring time of the olive paste and the addition of carbonate thereto on the olive yield. Table 5 shows the experimental design and the yield obtained, maintaining the general experimental conditions and the water temperature of the thermomixer at 20°C. TABLE 5 Experimental design and yields

Factors Response

Execution order Temperature °C Carbonate added, % Yield, %

4 20 0 16.06

3 90 0 19.04

1 20 1 17.96

2 90 1 19.76

In light of the results, the following information is obtained:

a) Average value: (16.06+19.04+17.96+19.76)/ 4= 18.21 %
b) Effect of temperature: (-16.06+19.04-17.96+19.76)/2 = 2.39%
c) Effect of carbonate: (-16.06-19.04+17.96+19.76)/2 = 1.31%
d) Effect of interaction (16.06-19.04.-17.96+19.76)/2 = -0.59%
In this case, the increase in stirring time has greater effect than the addition of carbonate, observing that the effect due to the addition of carbonate, 1.31 %, is very similar to that previously obtained, 1.49%.
A slight effect of interaction, 0.59%, is also observed.

Example 3.5. Combined study of the dose of carbonate, the temperature and the mixing time

To optimize the oil extraction yield in accordance with the stirring temperature, the stirring time and the addition of carbonate, an experimental design has been carried out based on the Response Surface Methodology, which allows us to inspect a response, which can be shown as a surface, when the experiments investigate the effect of varying quantitative factors in the values which take a dependent variable or response. In other words, it aims to find the optimum values of the independent variables or factors which maximize the response.

TABLE 6 Experimental design and yields

Factors				Response
Execution order	T: Temperature, °C	T: Time, min	C: Carbonate added, %	R: Yield, %
8	40	55	2	22.76
2	40	20	1	20.91
7	20	55	2	21.95
10	30	90	0	19.34
12	30	90	2	23.82
13	30	55	1	22.38
14	30	55	1	21.93
11	30	20	2	20.35
6	40	55	0	18.99
15	30	55	1	21.85
16	30	55	1	22.91
3	20	90	1	21.77
5	20	55	0	14.00
9	30	20	0	17.20
1	20	20	1	18.65
4	40	90	1	23.97

The data obtained have been adjusted to the explicative model using the statistics package Design-Expert. Then, the corresponding model is shown adjusted to the factors: temperature (T), time (t) and carbonate dose (C), Equation (3) and Table 7 shows the variance analysis.
(3) Yield (%) = -7.81089 + 1.35475 T + 0.042107 t + 18.235C -0.0187 T² - 1.995 C² - 0.718 T C + 0.010225 T² C

TABLE 7. Variance analysis for the adjusted model

Source	Sum of squares	Degrees of freedom	Average squares	Value of F	Value of p (Prob. >F)
Model	102.59		14.66	80.42	<0.0001
T: Temperature	13.16	7	13.16	72.20	<0.0001
t: Time	17.38	1	17.38	95.34	<0.0001
C: Carbonate	14.55	1	14.55	79.86	<0.0001
T²	2.87	1	2.87	15.76	0.00041
C²	15.92	1	15.92	87.36	<0.0001
T C	4.37	1	4.37	23.97	0.0012
T² C	2.09	1	2.09	11.47	0.0095
Residual	1.46	8	0.18
Lack of fit	0.74	5	0.15	0.63	0.6987
Pure error
Total	0.71	3	0.24
	104.05	15

R²	0.9860
R² of fit	0.9737
R² of prediction	0.9283

In Table 7, it can be seen that a value of F equal to 80.42 implies that the model is significant, that a value of the Lack of Fit equal to 0.63 implies that it is not significant with respect to the pure error and that the value of the fit determination coefficient 0.9737 is reasonably in accordance with the prediction 0.9283, for which reason it can be considered that the model obtained serves to predict the extraction yield as a function of the three operation variables studied.
In order to analyse the influence of each experimental point on the model, the Leverage statistical diagnoses were performed, standardized residual and Cook's distance in the response, finding that they were within normal ranges, for which reason it can be said that this model is stable in the range studied.
To observe the effects on the factors, in the range studied on the response (yield), the disturbance graphic was obtained. To do this, two factors were maintained constant varying the other within the design range and the value of the variable response was determined, observing that the factor which has less influence on the yield is the temperature. Therefore, Figure 5 represents the response surface and the corresponding contour graphic, in accordance with the factors of time and dose of carbonate added for a temperature of 30°C.
The optimization has been performed using a methodology of the desired function using the statistical package Design-Expert whereby the solutions shown in Table 8 have been found. TABLE 8. Optimums of the adjusted model

Number Temperature °C Time min Carbonate % Yield % Desired function

1 37 89 1.4 24.50 1,000

2 40 87 1.3 24.40 1,000

3 38 85 1.4 24.31 1,000

4 33 90 1.6 24.30 1,000
On the other hand, the adjusted model also allows us to compare the different working options shown in Table 9. TABLE 9. Different options for the operating variables

Temperature °C Time min Carbonate % Yield %

30 55 0 18.31

30 55 1 22.22

30 55 1.5 22.68

30 55 2 22.13

40 90 0 20.25

20 90 2 23.54

20 20 0 12.65

20 20 2 20.60
For operating conditions considered normal, 30°C temperature and 55 minutes stirring, not using carbonate, yield 18.31%, and using 1.5% carbonate, yield 22.68%, involves an improvement of 4.37 points, i.e. an improvement of 24% in the yield.
The carbonate permits working at low temperatures, 20°C, obtaining more yield, 23.54%, than working at high temperatures, 40°C, 20.25% yield, for a stirring time of 90 minutes.
In the extreme case of working at low temperatures 20°C and low stirring times 20 min, the yield between not using carbonate 12.65% or using it, 20.60%, involves an improvement of 7.95 points which is translated into an improvement of the yield of 63%.

Example 3.6 Comparison between calcium carbonate and talc

In order to compare the extraction efficacy between the calcium carbonate and talc, technological coadjuvants of physical action and, therefore, of the same nature, a series of tests has been carried out using doses of 1% and 2% of both. The talc used, Talcoliva brand, is marketed by the company Luzenac Group.

Table 10 shows the results obtained for samples of Picual and Arbequina olives, stirring in all cases the olive paste at 30°C (water temperature of the thermomixer) for 55 minutes.

TABLE 10. Yield (kg of oil/ 100 kg of olives)

Coadjuvant added	Picual 1	Picual 2	Arbequina
0% (Control)	15.38 ± 0.29^a	18.55 ± 0.13^a	22.33 ± 0.36^a
1% Carbonate	16.66 ± 0.18^bc	19.53 ± 0.08^b	24.71 ± 0.19^b
1% Talc	16.03 ± 0.07^b	19.34 ± 0.10^b	24.66 ± 0.23^b
2% Carbonate	16.75 ± 0.10^c	19.33 ± 0.10^b	24.89 ± 0.49^b
2% Talc	16.61 ± 0.14^bc	16.46^b	25.26 ± 0.36^b


ANOVA	p < 0.02	p < 0.01	p < 0.02

The data from Table 10 have been represented in Figure 6 and in it the increase in extraction yield produced is graphically observed, in all cases, due to the addition of a technological coadjuvant as ad the addition of calcium carbonate improves the yield with respect to the addition of talc.
Once the corresponding statistical processing of the data has been performed we conclude that there are no significant differences for a confidence level of 95% (p=0.05) between the yield produced using the same dose of carbonate or talc, however, on average, the yield obtained with carbonate exceeds in the majority of the cases the yield produced with talc.

Example 3.7 Quality of the oils produced with calcium carbonate

To evaluate the quality of the oils produced, using calcium carbonate, the quality criteria established in Commission Regulation (EC) no. 1989/2003 of 6 November 2003 has been taken into consideration, amending Regulation (EEC) no. 2568/91, relating to characteristics of olive oil and olive pomace oils as well as methods of analysis. Table 11 shows some results.

TABLE 11. Quality parameters of the oil obtained.

		Analytical determinations
Variety of olive	Carbonate added	Acidity, %	Peroxide index mEq O₂/ kg	K₂₃₂	K₂₇₀
Picual 1	0% (control)	0.14	7.96	1.51	0.13
	1%	0.15	7.43	1.40	0.12
	2%	0.16	8.08	1.40	0.14
Picual 2	0% (control)	0.16	10.00	1.39	0.13
	1%	0.15	9.37	1.40	0.13
	2%	0.14	8,84	1.27	0.11

Once the corresponding statistical processing has been performed on the results obtained, we can state that there are no significant differences, for a confidence level of 95%, in the quality parameters between the controls and the oils produced with carbonate. In all cases, they can be given the classification "extra virgin olive oil" according to European legislation.

REFERENCES.

Angerosa, F.; Mostallino, R.; Basti, C.; Vito, R. (2001) Influence of malaxation temperature and time on the quality of virgin olive oils. Food Chemistry 72:19-28.
Appendix to Council Regulation (EC) no. 151/2001 of 23 July 2001 amending Regulation no. 136/66/EEC and Regulation (EC) no. 1638/98, as regards the extension of the regime of aid and the quality strategy for olive oil. Official Journal of the European Communities. L201 Boskou, D. Química y tecnología del aceite de oliva. AMV Ediciones y Mundi-Prensa. Madrid, 1998.
Cert, A.; Alba, J.; León-Camacho, M.; Moreda, W.; Pérez-Camino, M.C. (1996) Effects of Talc Addition and Operating Mode on the Quality and Oxidative Stability of Virgin Oils Obtained by Centrifugation. J. Agric. Food Chem. 44:3930-3934.
European Commission (1991) Regulation (EEC) no. 2568/91 relating to characteristics of olive oil and olive pomace oils as well as methods of analysis. Official Journal of the European Communities. L. 248.
European Commission (2003) Regulation (EC) no. 1989/2003 amending regulation (EEC) no. 2568/91. Official Journal of the European Communities. L 295.
Di Giovacchino, L.; Sestilli, S.; Di Vincenzo, D. (2002) Influence of olive processing on virgin olive oil quality. Eur. J. Lipid Sci. Technol. 104:587-601.
Hermoso, M.; González, J.; Uceda, M.; García-Ortiz, A.; Morales, J.; Frias, L.; Fernández, A.; (1998) Elaboración de aceite de oliva de calidad. Obtención por el sistema de dos fases. Serie Apuntes 61/98. Regional Department of Agriculture and Fishing. Autonomous Government of Andalusia.
Martínez, J.M.; Muñoz, E.; Alba, J.; Lanzón, A. (1975) Informe sobre utilización del Analizador de Rendimientos "Abencor". Grasas y Aceites 26(6)379-385.
Montgomery, D.C.; Diseño y Análisis de Experimentos. Limusa Wiley. Mexico, 2002.
ORDER of 13 January 1986 approving the positive list of additives and technological coadjuvants for use in the preparation of edible vegetable oils. Spanish Official State Gazette (BOE) no. 19 of 22 January 1986.
ORDER of 30 November 1989 amending the positive list of additives and technological coadjuvants for use in the preparation of edible vegetable oils. Spanish Official State Gazette (BOE) no. 301 of 16 December 1989.
Royal Decree 3177/1983 of 16 November approving the Technical-health regulation of food additives. Spanish Official State Gazette (BOE) no. 310 of 28 December 1983.
Uceda, M.; Frias, L. (1975). Épocas de recolección. Evolución del contenido graso del fruto y de la composición y calidad del aceite. In Proceeding of the 2nd international meeting of olive oil. (pp. 125-128). Cordoba, Spain.

Claims

Use of a compound which comprises calcium carbonate as technological adjuvant.
Use according to the preceding claim where said coadjuvant is limestone.
Use according to any of the preceding claims where said coadjuvant is used in fat and oil extraction processes.
Use according to the preceding claim where the substance to extract is a vegetable oil.
Use according to the preceding claim where the vegetable oil is olive oil.
Use according to the preceding claim where the olive oil is of virgin or extra virgin olive oil type.
Use according to the preceding claim where the compound has a richness in calcium carbonate of at least 90%.
Use according to the preceding claim where the compound has a richness in calcium carbonate of at least 95%.
Use according to the preceding claim where the compound has a richness in calcium carbonate of at least 99%.
Use according to the preceding claim where the compound has a humidity of less than 5%.
Use according to the preceding claim where the compound has a humidity of less than 3%.
Use according to the preceding claim where the compound has a humidity of less than 1 %.
Use according to the preceding claim where the compound has a maximum particle diameter of 55 µm.
Use according to the preceding claim where the compound has a maximum particle diameter less than 44 µm.
Use according to the preceding claim where the compound has an average maximum particle diameter of 2.65 µm.
Use according to the preceding claim where the dose of the compound used is at least 0.01 %.
Use according to the preceding claim where the dose of the compound used is at least 0.1 %.
Use according to the preceding claim where the dose of the compound used is between 0.1-30%.
Use according to the preceding claim where the dose of the compound used is between 1-5%.
Use according to the preceding claim where the dose of the compound used is 3%.
Use according to the preceding claim where the dose of the compound used is 1 %.