ES2239547A1 - Method for analyzing mixture of solids and liquids of variable composition by ultrasounds, involves comparing experimental values to mathematical model, and obtaining percentage value of components of mixture by resolution of model - Google Patents

Abstract

The method involves measuring speed of ultrasounds in solids and liquids mixture, and obtaining experimental values of the speed of ultrasounds. The obtained experimental values are compared to a mathematical model related to the speed of ultrasounds. A percentage value of each one of components of the mixture is obtained by resolution of the mathematical model.

Description

Procedure and device to analyze by ultrasound a current consisting of a mixture of solids and liquids of variable composition.

Technical field

The present invention is framed in the area of products and procedures in the food industry, and in particular olive oil and the like.

State of the art

Currently, quality control in products and procedures in the food industry is a must, and for this purpose the use of ultrasound in these types of industries is constantly expanding. Low intensity ultrasound has been used to monitor procedures (flow meter, liquid level) or to determine the quality of food products. Applications can be found among others, for the control of products and procedures in the meat, dairy, post-harvest and oil industries. In these applications, ultrasound has been used to assess the composition, structure and physical condition of a wide variety of food materials. Most of the studies found in the literature use ultrasound speed to obtain product information, probably due to the fact that it is the simplest and most reliable ultrasound measurement
ble.

Ultrasound can also be applied to solve some problems related to the industry oil. In this regard the ultrasonic speed has been measured to determine the chemical structure of different oils, including chain length and degree of unsaturation (Javanaud & Rahalkah, 1988). Therefore, they can be used speed measures for the evaluation of the composition and adulteration of oil (Raghupathi, Siva & Prabhu, 1980). The rheological properties of edible oils (castor, olive, peanut, sunflower and rapeseed) have also been addressed through the use of ultrasound (Gladwell, Javanaud, Peers, Rahalkar, 1985). Benedito, Mulet, Velasco & Dobarganes (2002) found a correlation between the percentage of polar compounds and the ultrasonic speed and attenuation in fried olive oil, so that these parameters could be used to determine the time of elimination for this type of oil.

Another field in which ultrasound has proven to be a good alternative to traditional analytical techniques is in the evaluation of the composition, it being shown that the ultrasound method is fast reliable and not destructive for this purpose. It has been used to determine the sugar content in melons, the solid fat content in oils, fats and adipose tissue (Miles et al ., 1985) and the fat content in milk. In addition to these applications, ultrasound has been applied to evaluate the composition of low-fat pork, fish composition, the composition of pork mixtures, the composition of meat-based products
ne.

In several of the studies mentioned previously, speed (c) was considered at one or several temperatures for the estimation of the composition. Equation 1 is the most widely used for this purpose, considering that the sample It consists of a mixture of different components in proportions known and ultrasonic speeds.

(1) \ frac {100} {c2} = \ sum \ limits ^ {n} _ {j = 1} \ frac {\ phi_ {j}} {c_ {j} ^ {2}}

where \ phi_ {j} and c_ {j} are, respectively, the mass percentage and the ultrasonic velocity for component j. This equation has proven to be a good way to estimate the ultrasonic speed in materials food, where dispersion is not important, which implies that the air content must be low.

In the process of extracting olive oil a residue (alpechin) is generated that contains water, oil or other solid. Virgin olive oil is obtained from different varieties by mechanical extraction. In the extraction process shown in scheme 1, - simplified flow chart of a Three-phase olive oil extraction procedure-, the olives are crushed by hammer grinding, and pasta from olive is pumped to a malaxadora where it is heated and mixed until the drops of oil begin to separate and clump together. The Paste is pumped to a centrifuge where solids are separated from the liquids The aqueous phase and the oil are then separated into a final spin procedure (spin system three phases). Two streams of an aqueous phase (alpechin) are generated It contains water, solids and some oil.

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Scheme one

one

The design of new oil mills includes the automatic control of the different procedures involved in the production of virgin olive oil (Ortega, Mata, Palomar, Montoro & Cruz, 2001). A key point of the procedure is that the two centrifuges shown in scheme 1, which separate the vegetable oil in the extraction procedure, work correctly, otherwise the oil can be poured out with a residue in the final flow of alpechin. Alpechin residue poses a potential pollution problem, due to the major difficulties associated with its treatment and disposal. It is Particularly important is the fact that this residue has a chemical oxygen demand of approximately 230,000 ppm and a Biological oxygen demand of approximately 150,000 ppm.

The standard procedure used to analyze the Alpechin lipid content (UNE 55-114-84, 1984) implies extraction with diethyl ether, followed by evaporation and re-extraction with hexane, doing the procedure expensive and long. Therefore a method of continuous control of the composition of the different flows of alpechín would be of great interest to detect anomalies in the procedure and to calculate the approximate organic load of the residue.

The present invention seeks to resolve the problem of controlling the process of obtaining olive oil, in order to prevent the oil obtained from containing a residue of unwanted alpechin. Said residue poses a problem of major pollution This problem is solved by claimed process, according to which, through the use of Ultrasound is evaluated the composition of the residual liquid mixture of the oil mill and depending on that composition are modified the conditions and variables of the elaboration process to avoid oil losses in production, as well as limiting the pollution produced by the alpechin.

Brief Description of the Invention

The present invention relates first to a procedure to analyze the composition of a stream consisting of a mixture of solids and liquids of composition variable, characterized in that said procedure is performed in continuous and because it includes the stages of:

- perform at least one measurement of the speed of ultrasound in said mixture at at least two different temperatures, obtaining experimental values of the velocity of ultrasound,

- adjust the experimental values obtained in the previous stage to a mathematical model that relates the
ultrasonic speed with the composition and temperature, whose model has as a percentage the composition percentages for each of the components of the mixture, and

- obtain through model resolution mathematician the value of said percentages of each of the components of the mixture.

A second object of the present invention is a device to analyze the composition of a stream consisting of a mixture of solids and liquids of composition variable according to the described procedure, characterized in that understands:

- at least one mixing container with control of temperature, wherein said container comprises at least one ultrasound transducer,

- at least one ultrasonic generator / receiver comprising means for exciting said transducer, means for capture the ultrasound signal, means to amplify said signal and means to filter said signal, and

- means to analyze the signal of ultrasound

Detailed description of the invention

The present invention relates to a procedure to analyze the composition of a stream consisting of a mixture of solids and liquids of composition variable, characterized in that said procedure is performed in continuous and because it includes the stages of:

- perform at least one measurement of the speed of ultrasound in said mixture at at least two different temperatures, obtaining experimental values of the velocity of ultrasound,

- adjust the experimental values obtained in the previous stage to a mathematical model that relates speed of ultrasound with the composition and temperature, whose model it has as unknown the composition percentages for each one of the components of the mixture, and

- obtain through model resolution mathematician the value of said percentages of each of the components of the mixture.

They can be used in the stages of obtaining the percentages of composition, averaged values instead of absolute values, so that according to a particular embodiment the procedure to analyze the composition of a stream consisting of a mixture of solids and liquids of composition variable, includes the stages of:

- perform at least one measurement of the speed of ultrasound in said mixture at at least two different temperatures, obtaining experimental values of the velocity of ultrasound,

- obtain the average values of the values Experimental obtained in the previous stage for each temperature,

- adjust the average values obtained in the previous stage to a mathematical model that relates the speed of ultrasound with the composition and whose model has as unknowns the composition percentages for each of the components of mix,

- obtain through model resolution mathematician the value of said percentages of each of the components of the mixture.

The present procedure can be carried out over a mainstream, or over a diverted stream of a mainstream, so that it can comprise also:

- provide at least one derivation of a main oil stream,

- arrange in said branch means of heating / cooling, and

- arrange in said branch containers that they comprise ultrasound transducers and agitation means.

According to several alternatives of the procedure described, this can be carried out so that the, or the containers are not agitated, or they are agitated, or they can be under vacuum and not agitated, or they may be under vacuum and agitated

In any of his accomplishments the procedure may include a device calibration stage of measurement and analysis of the composition.

Preferably the current analyzed by the described procedure is a stream consisting of a mixture of solids and liquids of variable composition generated during oil processing, and more preferably even more virgin olive oil and the like.

A second object of the present invention is a device to analyze the composition of a stream consisting of a mixture of solids and liquids of composition variable according to the described procedure, characterized in that understands:

- at least one mixing container with control of temperature, wherein said container comprises at least one ultrasound transducer,

- at least one ultrasonic generator / receiver comprising means for exciting said transducer, means for capture the ultrasound signal, means to amplify said signal and means to filter said signal, and

- means to analyze the signal of ultrasound

A particular embodiment of the device understands:

- a derivation of a mainstream said bypass being fed by a flow pump adjustable,

- at least two systems of heating / cooling of the current in said branch.

- at least two mixing containers with control of temperature, wherein said containers comprise at least an ultrasound transducer,

- at least one ultrasonic generator / receiver comprising means for exciting said transducer, means for capture the ultrasound signal, means to amplify said signal and means to filter said signal, and

- means to analyze the signal of ultrasound

In any of its variants the device It preferably further comprises calibration means thereof.

Brief description of the figures

Figure 1. Ultrasonic speed dependence of the temperature in water, oil and vegetable water.

Figure 2. Ultrasonic velocity in low alpechin various experimental conditions of vacuum and with agitation.

Figure 3. Ultrasonic speed variation in line with the temperature in alpechin with different contents of oil.

Figure 4. Influence of oil content on Ultrasonic speed at different temperatures.

Figure 5. Influence of temperature on the ultrasonic speed of solids (protein and others), C_ {p + o}, calculated for samples of alpechín with different contents of oil (based on% moisture).

Figure 6. Oil composition of samples of Alpechin planned versus experimental.

Figure 7. Shows an embodiment of the device to carry out the procedure.

Embodiment of the invention

The preferred embodiment of the invention described below refers to the analysis of a stream consisting of a mixture of solids and liquids generated in the elaboration of olive oil.

Device and samples

The device used for the experiments it consisted of a cubic container (49 x 49 x 49 mm), in which placed the samples of alpechin, two transducers of ultrasound, a pulse receiver and an oscilloscope of digital storage

The container incorporates a temperature sensor and a mechanical stirrer, which allows to maintain the temperature of the sample. The temperature was controlled by placing this container in a pressure vessel, filled with water that partially covers the container. This vessel was heated using a heater domestic, operated by a digital controller, which allows carry out the experiments at atmospheric pressure and low empty.

The two ultrasonic transducers used are narrowband transducers, attached to the cubic container. The transducers were connected to a pulse receiver, which sent the electrical signals to the storage oscilloscope digital.

Samples

Alpechín and oil samples were obtained from a local olive oil mill, directly to start from the process flow. Alpechin and oil blends were prepared just before the experiments and the oil concentration varied between 0.9 and 15%. Speed Ultrasonic was measured in water, oil and vegetable water at a temperature between 6 and 50 ° C. Two equations were considered semi-empirical to evaluate the composition of oil, water and protein and other components.

The lowest oil content corresponds to alpechin extracted after the last spin, corresponds to minimum oil content that the vegetable water showed in the mill where the samples were obtained. Higher oil contents indicate a decrease in system efficiency, or a failure in a particular piece of equipment.

Chemical analysis of the samples

In the alpechin, the triplicate was analyzed in triplicate fat, protein and moisture content, according to the methods conventional. The fat was determined by solvent extraction (Method 991.36 A.O.A.C., 1997), the protein by the Kjeldahl method (Method 981.10 A.O.A.C., 1997) and humidity by oven drying (Method 925.40 A.O.A.C., 1997).

The chemical analysis of the vegetable water used in experiments showed that it consists of 91.95% by weight of water, 0.92% by weight of fat, 0.66% by weight of protein and 6.47% by weight of other components (determined by difference). These values are similar to those found in the bibliography although it is due to consider that the composition of alpechin is highly influenced by the type and performance of the procedure extraction.

Ultrasound measurements according to the procedure of the invention

Ultrasound measurements were carried out. over distilled water, oil and alpechin. All measures are carried out in the range of 6-50 ° C, using samples that had been cooled in a laboratory refrigerator and then heated in the pressure vessel. To find the better experimental conditions for the measurements led to carry out tests with vacuum application (70 mmHg) and without application of empty. For each type of experiment (with and without vacuum), made measurements while the samples were continuously shaken and also stopping the agitation just before the measure of ultrasound

For each measurement of ultrasound velocity They took and averaged five acquisitions. The time of the trajectory was computed on the averaged signal and speed Ultrasonic was calculated taking into account the delay of device.

For ultrasound measurements in pure oil and water, no difference was found between the different conditions of vacuum and stirring tested, and therefore the average value (figure 1) it was considered that it adjusted the experimental data to a mathematical equation In the case of water an equation was used polynomial (equation 2).

(2) C_ {W} = 1401 \ text {.} 9 + 5 \ text {.} 0305 \ T- 0 \ text {.} 0573 \ T ^ {2} + 0 \ text {.} 0002 \ T ^ {3} \ R2 = 0 \ text {.} 99

This equation indicates that the ultrasonic velocity increases at higher temperatures, although the proportion of the increase It decreases with temperature.

In the case of olive oil the speed ultrasonic decreased linearly with increasing temperature (figure 1) according to equation 3.

(3) V_ {o} = - 3 \ text {.} 4535 \ T + 1530 \ text {.} 6 \ R ^ {2} = 0 \ text {.} 99

The temperature coefficient for the ultrasonic velocity in olive oil (-3.45 ms -1 ° C -1) is very similar to that found by Ghaedian et al . (1998) for sunflower oil (-3.40 ms -1 ° C -1).

Figure 2 shows the results of the experiments in alpechin for different conditions rehearsed

Figure 3 shows the speed variation Ultrasonic with temperature for different samples of alpechin, which have oil contents that vary between 0.9 and 16%. How I know you can see, all curves are very similar to water behavior since these alpechin samples are in 83-93% water. It can be seen in figure 3 that at low temperatures, the ultrasonic speed is higher for higher oil contents, although the differences are not very big. As the temperature increases, the speed Ultrasonic increases in smaller proportion for samples with the higher oil content due to the coefficient of negative temperature (-3.45 m s -1 ° C -1) of the oil and These differences rise with increasing temperature.

Evaluation of the composition obtained by measuring the ultrasonic speed

Several studies have related speed with the concentration of a single component in a two-phase food (Ghaedian, Decker & McClements, 1997). As long as it consider only two components, this can be a good method to the estimation of the composition of the food.

Figure 4 shows the ultrasonic speed against the concentration at different temperatures (6, 12 and 32ºC). As can be seen at 6 ° C, the ultrasonic speed increases slightly with the temperature. At this temperature, the speed in water is lower than the speed in oil, and therefore, how much the oil content increases, the water content decreases and the Ultrasonic speed in the mix increases. This behavior is see also in figure 2 and, as indicated Previously, the differences are not very large, as you can observe on the slope of the line in figure 4. At 12ºC, the speed is almost independent of oil concentration due to the fact that the speed in the different components It's similar. In figure 1 you can see that at 12 ° C the oil and the Alpechin (water / protein / other components) have the same speed. In the case where only oil and water are considered, the  temperature at which both speeds are equal is 18 ° C. The difference in temperatures is attributable to the contribution of other components. For higher temperatures, the speed Ultrasonic decreases with increasing oil content (32 ° C, Figure 4) because at this temperature, the speed in the water It is greater than in oil. When the temperature rises, the difference becomes greater, and this can be seen on the slope more pronounced of the line in figure 4. Therefore, in the if only one speed should be considered for the evaluation of the composition (product of two components), the better results would be found for more temperatures high, where the differences are the maximum. It is possible that differences also rise to temperatures below 6 ° C; but Problems may occur with the solidification of the oil. For Alpechin, solid content (protein and other components) plays an important role that affects the ultrasonic speed at different temperatures, and therefore, measure the speed at a Only temperature is not enough to evaluate the composition.

In the case of alpechin, three components, water, oil and protein / others (solids) will be considered. Different authors have also considered these three components to assess the composition of solid food products (Ghaedian et al ., 1998; Simal et al ., 2003). For the determination of the composition of alpechin, two models will be evaluated.

Model one

Using equation 1 at two different temperatures and considering that the sum of the components is 100% of the product, the following system of three equations is obtained:

2

in which c_ {T1} is the speed ultrasonic at temperature T1 and c_ {oT1}, c_ {wT1}, c_ {p + oT1} are the ultrasonic speeds of oil, water and protein + others respectively at the temperature T1. \ phi_ {o} \ phi_ {w} and \ phi_ {p + o} are the percentages of oil, water and solids respectively, these being the variables Which are due obtain.

C_ {W} and C_ {o} at different temperatures can be calculated from equations 2 and 3, respectively. To obtain the relationship between C_ {p + o} and temperature, equations 2 to 5 were used for a set of samples of different concentrations. As an example, the C_ {p + o} calculated against the temperature is shown for four samples of different chemical composition in Figure 5. The C_ {p + o} decreases with the temperature in all samples. This behavior was also found in a study carried out for a "sobrasada" meat product (Simal et al ., 2003) where C_ {p + o} is also dependent on the composition of the sample. Therefore, an equation similar to the one proposed by these authors was adjusted to relate experimental data of C_ {p + o} with the temperature and oil content (Equation 7). Figure 5 shows the expected values obtained with equation 7.

(7) C_ {p + o} = 2686 \ text {.} 43 - 7 \ text {.} 89 \ phi_ {o} - 29 \ text {.} 01 T + 0 \ text {.} 30 T ^ {2}

To improve the accuracy in the computation of \ phi_ {o} \ phi_ {W} and \ phi_ {p + o} in equations 4-6, it is advisable to consider two temperatures sufficiently different to obtain significant differences between the coefficients of the equations 4 and 5. The ultrasonic velocity of the different components at these temperatures should also be different. Taking these premises into account, the temperatures chosen in this example were 6 and 32 ° C. Figure 6 shows the comparison between the actual oil content and the predictions using equations 4-6 for a new set of samples. As can be seen in this figure, there is a close relationship between the estimated and experimental data, with the justified variance of the 99% model for oil and 98.6% for moisture. For the solids content (protein and others) the ratio was worse (84%). Ghaedian et al . (1998) also found a close relationship between the actual fat content and the expected fat content, when considering equation 1 to determine the composition of fish. For pork products. Ultrasound was also shown as a good method to evaluate the composition (Benedito et al ., 2001; Simal et al ., 2003).

Model 2

An empirical model is proposed incorporating T, \ phi_ {o} and \ phi_ {p + o} (equation 8)

(8) C_ {T} = a + b \ T - c \ T2 + d \ T3 + (e-f \ T) (\ phi_ {o} - g) + (h - i \ T) (\ phi_ {p + o} - j)

where a-j are model constants. Taking into account equation (8) to two different temperatures and equation 6, you get a system of Three equations To obtain the coefficients of equation 8, you He used the Solver tool function of the Excel spreadsheet. The values were chosen to minimize the sum of differences of squares between experimental data at all temperatures and concentrations considered, and the values obtained by the model. The values of the constants are shown in the equation 9.

(9) C_ {T} = 1408 \ text {.} 45 + 12 \ text {.} 43180 \ T - 0 \ text {.} 03740 \ T ^ {2} + 0 \ text {.} 00005 \ T ^ {3} + (0 \ text {.} 78729 - 0 \ text {.} 11419 \ T) (\ phi_ {o} + 39 \ text {.} 75431) + (0 \ text {.} 00273 - 0 \ text {.} 70276 \ T) (\ phi_ {p + o} - 1 \ text {.} 00545)

Figure 6 shows the graph of the values real versus predicted values for oil content. Equation 9 was evaluated at 6 and 32 ° C and combined with equation 6 to get the three necessary equations for all three unknowns The percentage of the variance explained in model 2 was 97.6% for oil, 97.8% for moisture and 85% for content in solids. Although these values are slightly lower for the oil and moisture content than those found for model 1, both models show a good ability to evaluate the composition of streams of alpechín.

Through the procedure herein invention better control of the process of olive oil extraction.

The results obtained show the ability to measure the composition of alpechin using ultrasound, through online monitoring of the extraction procedure, so that oil losses can be calculated and the process can be adjusted, in case any problem is detected. By example, it is possible to detect when some equipment is not functioning correctly or it is necessary to perform maintenance. Knowing the content of oil, protein and other components ultrasound can be used to estimate the organic load of the alpechin, which is a very important factor, due to the great difficulties associated with the treatment and waste of this residue.

It can also be done through this procedure determine how the different compositions of the fraction of solids (protein and other components), derived from the use of different raw materials (variety of olives, grade of maturation) and procedural conditions, could affect ultrasonic measurements and model performance proposed.

This procedure can be used as a control of Quality of the oil production process.

The two models proposed in this study they predicted the composition of alpechin properly from ultrasonic speed measurements at two different temperatures. Temperatures must be chosen taking into account the relationship ultrasound / temperature of the different components in the mixture, in order to maximize the ultrasonic speed difference measure. An online system could be developed to detect when an oil content limit is reached desired in the different flows of aqueous solutions, and record the composition in order to calculate the organic load of the residue.  A current could be forced through a branch in which the temperature could vary quickly and the speed could be measured continuously in two sections of the pipe.

Device

According to a particular embodiment of the device to carry out the process of the present invention, said device, according to figure 7 comprises a shunt of the main stream or channeling (1), in which they are arranged: pumps (2), heating devices (3), ultrasonic transducers and containers or containers (4), a ultrasonic generator / receiver (5) and analysis equipment signal (6).

References

AOAC Official methods of analysis of AOAC international. 16th edition, 3rd revision, March 1997 .

Benedito , J., Carcel , JA, Rossello , C. & Mulet , A. ( 2001 ). Composition assessment of raw meat mixtures using ultrasonics. Meat Science , 57, 365-370.

Benedito , J., Mulet , A., Velasco , J. & Dobarganes , MC ( 2002 ). Ultrasonic assessment of oil quality during frying. J. Agric. Food Chem ., 50, 4531-4536.

Ghaedian , R., Coupland , JN, Decker , EA & McClements , DJ ( 1998 ). Ultrasonic determination of fish composition. J. Food Eng , 35,323-337.

Ghaedian , R., Decker , EA & McClements , DJ ( 1997 ). Use of ultrasound to determine cod fillet composition. J. Food Sci ., 62, 500-504.

Gladwell , N., Javanaud , C., Peers , KE, Rahalkar , RR ( 1985 ). Ultrasonic behavior of edible oils: correlation with rheology. Journal of the American Oil Chemists' Society , 62, 1231-1236.

Javanaud , C. & Rahalkah , RR ( 1988 ). Velocity of ultrasound in vegetable oils. Fat Sci. Technol ., 90, 73-75.

Miles , CA, Fursey , GAJ & Jones , RCD ( 1985 ). Ultrasonic estimation of solid / liquid ratios in fats, oils and adipose tissue. J. Sci. Food Agric ., 36, 215-228.

Ortega , A., Mata , JE, Palomar , JM, Montoro , V. & Cruz , F. ( 2001 ). Automatic control of oil mills. Food Equipment and Technology , 20 (157), 83-91.

Raghupathi , RC, Siva , RC & Prabhu , CAR ( 1980 ). Study of adulteration in oils and fats by ultrasonic method. Current Science ., 49 (5), 185-186.

Simal , S., Benedito , J., Clemente , G., Femenia , A. & Rossello , C. ( 2003 ). Ultrasonic determination of the composition of a meat-based product. J. Food Eng ., 58, 253-257.

Claims (12)

1. Procedure for ultrasonic analysis of the composition of a current consisting of a mixture of solids and liquids of variable composition, characterized in that said procedure is carried out continuously and that it comprises the steps of: - perform at least one measurement of the speed of ultrasound in said mixture at at least two different temperatures, obtaining experimental values of the velocity of ultrasound, - adjust the experimental values obtained in the previous stage to a mathematical model that relates speed of ultrasound with the composition and temperature, whose model it has as unknown the composition percentages for each one of the components of the mixture, and - obtain through model resolution mathematician the value of said percentages of each of the components of the mixture. 2. Method for analyzing the composition of a stream according to claim 1, characterized in that it comprises the steps of: - perform at least one measurement of the speed of ultrasound in said mixture at at least two different temperatures, obtaining experimental values of ultrasound velocity, Y - obtain the average values of the values Experimental obtained in the previous stage for each temperature, - adjust the average values obtained in the previous stage a mathematical model that relates the speed of ultrasound with the composition and whose model has as unknowns the composition percentages for each of the components of mix, - obtain through model resolution mathematician the value of said percentages of each of the components of the mixture. 3. Method according to one of the preceding claims, characterized in that it further comprises: - provide at least one derivation of a mainstream, - arrange in said branch means of heating / cooling, - arrange in said branch containers that they comprise ultrasound transducers and agitation means. 4. Method according to claim 3, characterized in that the containers are not agitated. 5. Method according to claim 3, characterized in that the containers are agitated. 6. Method according to claim 3, characterized in that the containers are under vacuum and not agitated. 7. Method according to claim 3, characterized in that the containers are under vacuum and agitated. Method according to any one of the preceding claims, characterized in that it further comprises a step of calibrating the measuring device and composition analysis. Method according to any one of the preceding claims, characterized in that said stream consisting of a mixture of solids and liquids of variable composition is a stream generated during olive oil production. 10. Device for analyzing the composition of a stream consisting of a mixture of solids and liquids of variable composition according to the method of claim 1, characterized in that it comprises: - at least one mixing container with control of temperature, wherein said container comprises at least one ultrasound transducer, - at least one ultrasonic generator / receiver comprising means for exciting said transducer, means for capture the ultrasound signal, means to amplify said signal and means to filter said signal, and - means to analyze the signal of ultrasound 11. Device for analyzing the composition of a current according to claim 10, characterized in that it comprises: - a derivation of a mainstream said bypass being fed by a flow pump adjustable, - at least two systems of heating / cooling of the current in said branch. - at least two mixing containers with control of temperature, wherein said containers comprise at least an ultrasound transducer, - at least one ultrasonic generator / receiver comprising means for exciting said transducer, means for capture the ultrasound signal, means to amplify said signal and means to filter said signal, and - means to analyze the signal of ultrasound 12. Device according to claim 10 or 11, characterized in that it further comprises calibration means thereof.