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[EN] In the dry-cured ham industry, an accurate control of the dry-salting process is especially complex because of the great heterogeneity of the meat pieces and the effect of different operational variables. The main objective of this study was to evaluate the feasibility of using an ultrasound system and methodology, adapted to the industry requirements, for the online monitoring of the ham dry-salting process. For that purpose, hams were dry salted for different times (4, 10, 11, 14, 16 and 30 days) at 2 degrees C. The cushion zone of the ham was placed over the transducers during salting and ultrasonic signals were taken automatically (5 min interval by using pulse-echo mode. Several methods of signal analysis were considered in order to assess the time of flight (TOF). TOF estimations by means of the energy threshold and cross-correlation methods (between the initial ultrasonic signal and the remaining signals measured during salting and between consecutive signals 5 min apart without interpolation) were affected by the low signal-to-noise ratio and the pulse distortion and were discarded for the online monitoring of ham salting. Otherwise, the cross-correlation method between consecutive signals (5 min apart) with interpolation n = 3 (CCM-CS n = 3), between non-consecutive signals (1 h apart) (CCM-NCS) and the phase spectrum method (PSM), provided close estimations of the variation of the TOF, which correlated well with the ham salt gain (R-2 = 0.83 for CCM-CS n = 3, 0.93 for CCM-NCS and 0.90 for PSM). Consequently, the use of ultrasonic pulse-echo TOF measurements could be considered as a simple, non-invasive, non-destructive and reliable technique for the industrial monitoring of the ham dry-salting process., This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), Institute Nacional de Investigacion y Tecnologia Agraria y Alimentaria and European Regional Development Fund (ERDF 2014-2020) (project RTA 2013-00030-C03-02), and by the Universitat Politecnica de Valencia through the FPI grant awarded to Marta de Prados (SP-1.2011-S1-2757).

[EN] In the present study, the use of the air-coupled ultrasonic technique has been analysed as a new tool for the contactless assessment of the avocado post-harvest textural modifications during ripening. Thus, ultrasonic parameters, such as maximum wave amplitude and ultrasound velocity, and textural ones, such as hardness, elastic modulus and relaxation capacity, were measured on avocado slices. During ripening, avocado reduced its elastic modulus (from 2.29 +/- 0.75 to 0.16 +/- 0.08 MPa), became softer and became more viscoelastic, which was well described from zero and first-order kinetic models. These changes increased ultrasound attenuation, decreasing the maximum amplitude of the ultrasonic signal (from 336.6 to 55.4 V/m), while the ultrasonic velocity remained constant, between 320.1 +/- 6.9 and 316.4 +/- 82.6 m/s. Thereby, the maximum ultrasonic amplitude, which adequately correlated with textural parameters (r(avg) = 0.85), could be used to assess the post-harvest ripening on avocado slices., The authors acknowledge the financial support from the Ministerio de Economia y Competitividad (MINECO) and Agencia Estatal de InvestigaciOn in Spain (Project RTC-2017-6314-2) and the Generalitat Valenciana. M.D. Farifias is grateful to the European Social Fund (ESF 2014-2020) and Generalitat Valenciana for her post-doctoral fellowship (APOSTD/2018/203). The author E.A. Sanchez-Torres acknowledges the support of the undergraduate student Sara Serrano Garcia on the experimental work.

For the first time, this study addresses the use of non-destructive ultrasound to monitor ham post-salting. For that purpose, the ultrasonic velocity (1 MHz) and the weight loss of hams were measured regularly every 2 days up to 8 weeks after salting. Additionally, for different post-salting times, internal salt and moisture content and hardness were measured at different locations from the ham surface. The experimental results reflected that the ultrasonic velocity increased as the ham weight decreased (26.1 m/s per kg), showing a satisfactory correlation between both variables (r = 0.95). The ultrasonic velocity was also correlated with the salt and moisture content. However, ham hardness remained fairly constant during post-salting, which confirmed that characteristic textural changes mainly occur during the salting and drying-maturation stages. Thus, the ultrasonic velocity could be a reliable parameter with which to monitor not only overall modifications in ham weight, but also internal changes of moisture and salt content during post-salting in a non-destructive way.

The dry-cured pork ham industry lacks non-destructive quality control techniques able to characterize relevant textural defects, such as pastiness or softness. The aim of this study is to analyze the feasibility of using different destructive and non-destructive techniques to characterize pastiness in dry-cured ham. Dry-cured ham processing was modified in order to induce different pastiness intensities over a wide range of moisture and salt contents. Afterwards, pastiness was assessed by sensory analysis and samples classified as non-pasty, medium-pasty and highly-pasty. Finally, chemical, textural, microstructural (LM and TEM) and ultrasonic analyses (velocity and attenuation coefficient) were carried out. Samples with a high degree of pastiness experienced an increase of 16.8% and 16.7% as regards the proteolysis index and relaxation capacity, respectively, and a 67.7% decrease in hardness compared to non-pasty hams. The microstructural analysis revealed that pastiness brought about great structural degradation. Ultrasonic velocity was significantly related to the salt (r = 0.79) and moisture contents (r = 0.69), but no influence of pastiness was found on the velocity. However, the attenuation coefficient increased as the pastiness rose and could be considered as a useful parameter for characterizing this complex textural defect. Therefore, ultrasound could be used not only to carry out a non-destructive characterization of dry-cured ham composition but also to assess pastiness. info:eu-repo/semantics/acceptedVersion

An airborne ultrasonic technique was tested for the determination of textural properties rapidly and contactless on pork burger patties under different compositions both at 5 °C and 20 °C. A high correlation between resonance frequency and firmness at 5 °C was observed (R=0.95), concluding that this technique shows a high potential for its use on meat industry.

[EN] Bearing in mind the highly variable salt content in dry-cured meat products with anatomical integrity, such as pork loin or ham, non-destructive salt content characterization and the online monitoring of dry salting are highly relevant for industrial purposes. This study explores the ability of low-intensity ultrasound to monitor the dry salting of pork Biceps femoris (BF) and Longissimus dorsi (LD) online, as well as to estimate the salt content, both in these muscles and in hams. For this purpose, meat samples were dry salted for up to 16 d at 2 C. During the salting of the muscles, the ultrasonic velocity was continuously measured at time intervals of 5 min, while in the hams it was measured before and after salting. The ultrasonic velocity increased progressively during the salting due to salt gain and water loss, reaching a velocity variation (DV) of 46.8 m/s after 16 d of dry salting for hams and 59.5 and 30.6 m/s after 48 h of dry salting for LD and BF, respectively. Accurate correlations between salt gain and DV were obtained (R2 ¿ 0.903 in LD-BF muscles and R2 ¿ 0.758 in hams), which allowed the assessment of the salt content with an average estimation error of 0.4% w.b. for both muscles and hams. Further research should investigate the use of the time of flight obtained through the pulse-echo mode, instead of the ultrasonic velocity, in order to improve the industrial applicabili, This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA) and European Regional Development Fund (ERDF 2014-2020) (contract n. RTA2013-00030-C03-02), by the PROMETEOII\2014\005 and by the Universitat Politecnica de Valencia (UPV) through the FPI grant awarded to Marta de Prados (SP-1.2011-S1-2757).

[EN] Mild thermal treatments could be considered a feasible technique with which to improve the texture of dry-cured ham. This study explores the feasibility of using power ultrasound (PuS) to intensify heat transfer during the mild thermal treatment of dry-cured ham immersed in a liquid medium. For that purpose, a temperature controlled ultrasonic bath was used to avoid the water temperature rise due to cavitation during ultrasonic application, which could mask the actual effect of ultrasound in heat transport mechanisms. Experiments were carried out using dry-cured ham slices (thickness 2 cm), which were heated at different temperatures (40, 45, 50 degrees C) with (PuS) and without (conventional mechanical stirring, CV) ultrasonic assistance. Temperature was monitored in the two main muscles of the ham (Biceps lemons and Semimembranosus) and in different positions of the slice. A model that considered heat transfer entirely controlled by conduction was chosen for describing heating kinetics and quantify the influence of temperature and ultrasonic application in the apparent thermal diffusivity. The heat conduction model proposed was adequate to describe both CV and PuS heating kinetics (VAR > 98.6%). Ultrasound application sped up the heat transfer by increasing the apparent thermal diffusivity up to 51%, but the higher the temperature, the lower the ultrasonic intensification. The apparent thermal diffusivities identified for the slices were satisfactorily validated (VAR > 98.4%) in independent experiments with ham cylinders. Therefore, PuS could be considered as an effective technology for the purposes of accelerating the heat transfer, thus shortening the heating time of dry-cured ham slices immersed in a liquid medium., The authors acknowledge the financial support from the "Spanish Ministerio de Economia y Competitividad (MINECO), Instituto Nacional de Investigation y Tecnologia Agraria y Alimentaria (INIA)" in Spain, the European Regional Development Fund (ERDF 2014-2020) (Project RTA2013-00030-C03-02) and the PhD grant of M. Contreras from Universitat Politecnica de Valencia.

[EN] Power ultrasound is applied in food technology to intensify extraction processes, due to the phenomena ultrasonic energy induces in the medium, enhancing mass transfer. The purpose of this work was the acoustic characterization of four transducers of different geometries and the evaluation of their performance in the ultrasonically assisted supercritical fluid extraction of antioxidants from oregano. The transducers differed in the amount of energy transmitted into the medium. Designs varied from the base model (T1), a larger cylindrical headmass (T2), a stepped circular section sonotrode (T3) and a multiplate configuration (T4). The highest nominal power density provided according to the calorimetric method was for T4 (151.6 +/- 7.1 W/L). The T2 produced a more uniform acoustic field and a higher acoustic pressure (150.6 +/- 20.5 kPa). Both parameters had an impact on total phenolics and antioxidants extraction with CO2 under supercritical conditions (35 MPa, 35 degrees C, 2.3% ethanol as co-solvent). T4 and T2 were equally efficient (4.0 +/- 0.2 and 4.2 +/- 0.2 mg GA/g) for phenolic extraction, and with respect to antioxidant capacity, the best performance was that of T4 (26.4 +/- 1.1 mu mol TE/g). Of the antioxidant compounds extracted, flavones and flavanones were identified. Therefore, transducer geometry influenced the amount and distribution of energy transmitted into the medium, thus determining the efficiency of the extraction process., This work was supported by the PROMETEOII\2014\005 project financed by the Generalitat Valenciana (Conselleria d'Educacio, Cultura i Esport, Valencia, Spain).

[EN] Online ultrasound measurements were taken using pulse-echo mode in loins (Longissimus dorsi) and hams at different salting times (up to 30 days). From the time-domain ultrasonic wave, the time of flight (TOF) was computed as well as its variation between two signals (Delta TOF). A progressive decrease in TOF during dry salting was found, which was linked to the salt gain, water loss and the reduction in sample thickness. Predictive models based on the ultrasonic parameters (Delta TOF and initial time of flight, TOF0) correctly classified 85% of the loins and 90% of the hams into 3 groups of salt content (low/medium/high): The results obtained confirm that the use of the ultrasonic pulse-echo technique is of great potential in the non-destructive monitoring of dry salting in pork loins and hams, as well as in the prediction of the salt gain for classification purposes. (C) 2017 Elsevier Ltd. All rights reserved., This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), the Instituto Nacional de Investigation y Tecnologia Agraria y Alimentaria (INIA) and the European Regional Development Fund (ERDF 2014-2020) (contract n. RTA2013-00030-C03-02), by the PROMETEOII\2014\005 and by the Universitat Politecnica de Valencia (UPV) through the FPI grant awarded to Marta de Prados (SP-1.2011-S1-2757)

[EN] Ultrasonic velocity was used to characterise the differences in composition and texture of Biceps Femoris muscles from four batches of pigs of different genetics (Iberian and Iberian x Duroc) and feeding systems ("montanera" and concentrate). Significant differences (p, The authors acknowledge financial support from the "Ministerio de Educacion y Ciencia" in Spain (Projects RTA 2010-00029-004-02: CONSOLIDER - Ingenio 2010: CARNISENUSA (CSD2007-00016)) and the valuable advice of Professor Jesus Ventanas.

Pork loin (longissimus dorsi) samples of two different geometries, cylinders and slabs, were immersed in saturated NaCl brine for 45min under different conditions: without brine agitation (STAT), with brine agitation (AG) and with ultrasound application (US) at eight levels of ultrasonic intensity. Moisture content change and NaCl gain were considered in order to evaluate the difference in the brining treatments. No significant differences were found in moisture and NaCl content of samples treated under STAT conditions and AG conditions, while the influence of ultrasound on the mass transfer process during meat brining depended on the intensity applied. There was an ultrasonic intensity threshold above which the influence of ultrasound appeared. At the highest level of intensity studied, the water content of samples was significantly higher than the initial water content of meat. As regards NaCl transfer, once above the intensity threshold, the increase in the NaCl content was proportional to the applied ultrasonic intensity. Not statistically significant differences were found for sample geometry.

The influence of the ultrasonic intensity in water and dry matter transport on a system constituted by apple and sucrose solution was studied in this work. Apple slices were immersed in a 30 °Brix sucrose solution at 30 °C. Three types of treatments were carried out: static (ST), with agitation (AG) and with ultrasound application (US) at five different levels of intensity, characterized using a calorimetric method. After 45 min treatment, the water losses and the increase of dry matter were significantly higher in US samples than ST samples when the ultrasonic intensity was above 10.8 W/cm 2 . At 11.5 W/cm 2 , the increase of dry matter was significantly higher than in samples from AG experiments. Diffusivity of water and dry matter was identified using a model based on Fick’s law. Ultrasonic treatments (11.5 W/cm 2 ) supposed an increase of 117% for water diffusivity and 137% for dry matter diffusivity compared with ST experiments.

In this work, the use of ultrasonics and surface tests for cheese quality evaluation was studied. Manchego cheese pieces matured from 29 to 296 d were used. The internal and external texture of Manchego cheese determined from uniaxial compression, puncture test and surface probes, increased during maturation. Ultrasonic waves were highly scattered in Manchego cheese due to porosity. Ultrasonic velocity decreased linearly with temperature, the temperature coefficient ranging from −5.72 to −3.28 m s−1 °C−1. Velocity related well to textural parameters such as compression work and hardness ( R 2 = 0.843 and 0.826, respectively). The experiments carried out with surface probes attached to a texture analyzer showed a good relationship between internal and external textural parameters. These results show the feasibility of using ultrasonics and surface probes for quality control purposes, to assess texture and the maturation degree measured as days of storage in the curing chambers.

The use of ultrasonics as an analytical technique to estimate the composition of a fermented meat-based product (sobrassada) was assessed. Moisture, fat and protein contents and ultrasonic velocity at 4, 8, 12 and 25 °C were measured in samples using different formulae. In this study, it was considered that a meat-based product is formed of three different constituents: fat, water and protein+others. Ultrasonic velocity was related, by a semiempirical equation, to the composition and the ultrasonic velocity of the above three components. The ultrasonic velocity temperature dependence allowed the determination of fat, moisture and protein+others contents. The explained variance was 98.0% for protein+others, 97.6% for fat and 95.6% for moisture. The results obtained show the feasibility of using ultrasonic velocity measurement to assess, in a rapid and non-destructively way, the composition of a meat-based product.

The relationship between textural properties of a meat-based product (sobrassada de Mallorca) and ultrasonic velocity was examined. Textural properties (at 4 °C) and ultrasonic velocity (at 4, 8, 12 and 25 °C) were measured. The ultrasonic velocity could be mathematically related with the textural parameters such as hardness and compression work (CW). The results showed that using a non-destructive method such as ultrasonic measurements, hardness and CW could be accurately estimated (%var=95% in both parameters). Moreover, the measurement of ultrasonic velocity at different temperatures showed that velocity decreased when temperature increased. Thus, from the slope of the temperature–velocity straight lines it was possible to assess, in a non-destructive way, the moisture and fat contents of the meat-based product (%var=91% and 93%, respectively).

The usefulness of ultrasonic velocity measurements as a non-destructive technique to evaluate the moisture content and textural properties of sobrassada de Mallorca (a raw cured pork product) was assessed. Moisture content, ultrasonic velocity and textural properties were periodically measured in samples of sobrassada during ripening at 15°C and 75% RH. From the results obtained, two periods of ripening could be clearly distinguished, a first period (0–40 days of ripening) and a second period (40 to the end of the ripening), under the experimental conditions used in this study. The ultrasonic velocity could be mathematically related with the moisture content and textural parameters such as hardness, compression work, maximum puncture force and puncture work during the first period of ripening. In the second period, some physical modifications were inferred to occur which could be detected through the textural parameters, the ultrasonic velocity and by using optical microscopy. Overall, these results showed the ultrasonic techniques could be used to accurately estimate the moisture content and the textural parameters of sobrassada during the first period and also as a reliable method to detect changes in textural properties after prolonged ripening.

Low-intensity ultrasonics frequently range at intensities lower than 1 W/cm2and at frequencies higher than 100 kHz. They are used in food industries for both process control and product assessment or control. Two kinds of techniques are used, through-transmission and pulse-echo. The most commonly used ultrasonic parameters are velocity and attenuation. The applications of low-intensity ultrasonics are encountered in all food industries mainly vegetables, dairy, and meat. When traveling through a medium, the ultrasound waves change their characteristics and the analysis of this change allows assessment of properties of the medium. Different properties of foods have been addressed in the past and have mostly been linked to texture (maturity, ripeness in cheese, melons, avocados, etc.), composition, or even sensory characteristics. Defect detection such as cracks in cheese or hollow hearts in potatoes has also been addressed.

[EN] This work addresses the use of ultrasound (US) and medical dual energy X-ray absorptiometry methods to predict the fat content in green pork hams. Ultrasonic velocity (õ) and X-ray absorption were measured in 78 green hams. An increase in the fat content involved an increase in õ and a decrease in the X-ray attenuationmeasured at 2 °C.Models developed to predict the fat content fromthe ultrasonic velocity or X-ray parameters provided errors of 2.97% and 4.65%, respectively. The combination of both US and X-ray technologies did not improve prediction accuracy. These models allowed green hams to be classified into three levels of fatness, with 88.5% and 65.4% of the hams correctly classified when using models based on ultrasonic and X-ray parameters, respectively. Therefore, US and X-rays emerge as useful quality control technologies with which to estimate the fat content in green pork hams, This work was supported by the spanish Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA) (contracts n. RTA2010-00029-CO4-01/02) and by Universitat Politecnica de Valencia (UPV) through the FPI grant given to Marta de Prados (SP-1.2011-S1-2757).

Ultrasonic velocity was related to sensory and instrumental texture measurements. A semi-logarithmic model (Weber-Fechner) was used to relate the sensory and instrumental texture measurements. The ultrasonic velocity ranged from 1650 to 1723 m/s for the softest and hardest cheese, respectively. As expected from theoretical equations, the ultrasonic velocity was related to the square root of the instrumental measurements. The deformability modulus (r 2 =0.93) and the slope in puncture (r 2 =0.85) were the most closely related parameters. A model developed from the relationship between sensory and instrumental texture and the relationship between ultrasonic velocity and instrumental texture, was used to relate velocity to sensory measurements. Elasticity (r2 = 0.84) and firmness (r 2 = 0.81) were the sensory attributes which best correlated with ultrasonic velocity. From the obtained results, it was concluded that ultrasonic velocity measurements could be used to assess instrumental and sensory properties of Mahon cheese texture nondestructively, and therefore could be used for grading purposes.

The ultrasonic velocity in Cheddar cheese is temperature dependent. This relationship can be used to make corrections when determining ultrasonic texture or to determine mean temperatures in cooling/heating processes. At 0 < T < 35 °C ultrasonic velocity was 1590 to 1696 m/s, at 0 and 35 °C, respectively. Differential Scanning Calorimetry thermograms linked the temperature dependence of ultrasonic velocity to fat melting. Three parts are distinguished in the curve as a consequence of the fat melting and the appearance of free oil. The most reliable temperature interval to carry out ultrasonic measurements in Cheddar cheese is identified as 0 to 17 °C.

Ultrasonic applications can be classified into low intensity or high intensity applications. The latter are used to modify a process or product with ultrasonics, while in low intensity applications the process or product modifies the ultrasonic signal, thus providing information about the product. Low inten sity ultrasonics in food technology can be used to monitor a process (liquid level, flowmeters) or to determine the quality of food products. Since ultrasonic techniques are rapid, non-destructive, easy to automate and relatively inexpensive, the number of applications is rapidly growing in this field. Ultrasonics can also be considered for use in laboratory testing devices to determine physical and chemical properties of foods. Ultrasonics has been used to determine texture, composition and physical state in liquid and solid foods. The commonly measured ultrasonic parameters are velocity, attenua tion and frequency spectrum composition. Velocity is the parameter used most since it is the simplest and most reliable measurement. This paper reviews the basic principles of ultrasonics, the most suit able techniques for each type of application, the testing devices needed to make measurements and the most interesting applications.

Experiments on osmotic dehydration of 1 cm apple cubes in 70 °Brix sucrose solution using ultrasound treatment were carried out at 40, 50, 60 and 70 °C. Acoustic pressure and frequency was measured to characterize the ultrasonic bath. Mass transfer was described by Fick's unsteady state diffusion equation. An important influence of the solution temperature on water transport was obtained. Measured water diffusivity coefficients (Dw) ranged from 2.6 × 1010−10 m2 s−1 at 40 °C to 6.8 × 10−10 m2 s−1 at 70 °C. Similar sucrose gain was measured at different temperatures, with an average effective sucrose diffusivity coefficient (Ds) (7.9 ± 0.2) × 10−11 m2 s−1. Similar experiments were performed under dynamic agitation conditions. A significant decrease in water and solute transport rates was detected when agitation was applied instead of sonication.

Ultrasonic measurements were used to characterize the effect of high pressure treatment (HPT) (600 MPa/6 min) or cold storage (6 °C/120 days) on the textural properties of vacuum packaged dry-cured ham. The ultrasonic velocity, textural properties and fat content were determined in the ham packages. The ultrasonic velocity was related to the ham hardness, which depends on the sample composition. HPT induced molecular alterations which resulted in an average increase in the hardness of lean tissue of 0.2 N and one of 0.3 N in that of fatty tissue. These textural changes give rise to a velocity increase (8 m/s for lean and 17 m/s for fatty tissue). The cold storage of the Iberian hamalso led to an increase in hardness (average 1.10 N) and ultrasonic velocity (average 70 m/s). Therefore, the non-destructive ultrasonic technique could be a reliable method with which to assess the textural changes induced by HPT or cold storage on packaged dry-cured ham., The authors acknowledge the financial support from the "Ministerio de Economia y Competitividad" in Spain (Project RTA 2010-00029-C04-02).

[EN] The effect of ultrasound on the SC-CO2 inactivation kinetics of E. coli at different pressures (100, 225, 290 and 350 bar; 36 degrees C), temperatures (31 degrees C, 36 degrees C and 41 degrees C; 225 bar) and varying the composition of the medium (LB Broth, apple and orange juice) was studied. Using only SC-CO2 the inactivation rate in LB Broth increased progressively as the pressure or temperature rose and the average (for the different process conditions) time needed to achieve a reduction of 8 log-cycles was 50 min. When both SC-CO2 and ultrasound were used in LB Broth, 95% less time was needed, on average, to achieve the same reduction of 8 log-cycles and the effect of pressure and temperature was minimized; this reduction being achieved after only 2 min at 31 degrees C and 225 bar. Using the ultrasonic system led to a shorter process time regardless of the treatment medium, preventing the inhibitory effect that the solutes from the juices had on the SC-CO2 inactivation. The technology developed permits both a drastic decrease in SC-CO2 inactivation times and also the use of mild process conditions, which could lead to an increase in the quality of the product treated under this new technique. Industrial Relevance: Supercritical carbon dioxide (SC-CO2) inactivation technology represents a promising nonthermal processing method, although a too long treatment time is required to guarantee food safety. A patented inactivation technique based on Supercritical Fluids incorporating an ultrasonic transducer is presented. A drastic decrease of the inactivation time is found when high power ultrasound is applied to the SC-CO2 inactivation process coupled with the food industry's need for short process times. The inactivation process is improved regardless of the pressure, temperature or treatment medium. Therefore, mild process conditions (time, pressure, temperature) can be used, which result in a higher quality treated product. (C) 2012 Elsevier Ltd. All rights reserved., The authors acknowledge the financial support from the project CSD2007-00016 (CONSOLIDER-INGENIO 2010) funded by the Spanish Ministry of Science and Innovation and from the project PROMETEO/2010/062 financed by the Generalitat Valenciana. We thank Dr. Paula Alepuz for the generous gift of E. coli DH1 strain.

S alting process plays a key role in the preservation and quality of dry-cured meat products. Therefore, an adequate monitoring of salt content during salting is necessary to reach high quality products. Thus, the main objective of this work was to test the ability of low intensity ultrasound to monitor the salting process of pork meat. Cylindrical samples (diameter 36 mm, height 60±10 mm) of Biceps femoris were salted (brine 20% NaCl, w/w) at 2 oC for 1, 2, 4 and 7 days. During salting and at each experimental time, three cylinders were taken in order to measure the ultrasonic velocity at 2 oC. Afterwards, the cylinders were split in three sections (height 20 mm), measuring again the ultrasonic velocity and determining the salt and the moisture content by AOAC standards. In the whole cylinders, moisture content was reduced from 763 (g/kg sample) in fresh samples to 723 (g/kg sample) in samples salted for 7 days, while the maximum salt gain was 37.3 (g/kg sample). Although, moisture and salt contents up to 673 and 118 (g/kg sample) were reached in the sections of meat cylinders, respectively. During salting, the ultrasonic velocity increased due to salt gain and water loss. Thus, significant (p

[EN] Fresh cheese composition was assessed by measuring ultrasonic velocity in cheese and cheese blends at different temperatures Twenty types of commercial fresh cheeses with fat contents ranging from 0 2% to 17 6% w b were analyzed Ultrasonic velocity was not only heavily dependent on the composition of the cheese but also on its structure Based on the different effect temperature has on velocity in water and fat a semi-empirical model was used to estimate the cheese composition from velocity measurements at six temperatures ranging from 3 to 29 degrees C The model provided good results for the assessment of the fat (R-2 = 0 984/0 996 RMSE = 46/1 1 for whole and blended cheese respectively) and water (R-2 = 0964/ 0 995 RMSE = 6 5/0 7 for whole and blended cheese respectively) content The ultrasonic measurements could be carried out during the cooling process that takes place after curdling and used as a quality control tool to detect process anomalies in-line (C) 2010 Elsevier Ltd All rights reserved, The authors acknowledge financial support from the Ministerio de Educacion y Ciencia in Spain (Project AGL 2007-65923-C02-02) and the National Council for Scientific and Technological Development CNPq in Brasil (Proc No 200918/2007-9) and the UPV (Vicerrectorado de Investigacion Desarrollo e Innovacion Proc No 246)

Ultrasound pulses are transmitted through samples of vacuum-packaged dry-cured ham of different thicknesses. These measurements permitted us to get simultaneously both velocity of ultrasounds and thickness of the package. These results are compared with those obtained using a classical ultrasonic direct-contact technique and a conventional thickness gage. Deviation of velocity and thickness measured with air-coupled ultrasounds respect to the standard techniques is 1.86% and 2.98%, respectively. This confirms the possibility to use air-coupled ultrasound to assess the properties of dry-cured ham. This technique presents the advantages of being completely non-contact, clean, rapid, and requires no independent thickness measurement

Nowadays, due to the more global nature of markets, the commercialization of cheese relies on the high quality of the product. Internal defects such as cracks or flaws may affect quality. Two different nondestructive inspection techniques (ultrasonic and acoustic experiments) were used to detect cracks in Manchego cheese. The existence of small eyes in this type of cheese limited the use of ultrasonic pulse-echo experiments due to high scattering, and only cracks close to the surface of the cheese could be detected. The acoustic impulse-response technique, however, allowed us to study wheel pieces with cracks located elsewhere in the cheese. Two different impact probes (A and B) were assayed. The energy content of the acoustic spectrum was higher for cracked wheel pieces (7,116 and 17,520 V Hz(1/2) for probes A and B, respectively) than for normal ones (6,841 and 16,821 V Hz(1/2)). The differences were mainly found for frequencies higher than 150 Hz, which made the centroid for cracked pieces higher (162 and 170 Hz for probes A and B, respectively) than that for normal cheeses (132 and 148 Hz for probes A and B, respectively). Discriminant functions were developed to classify wheel pieces, and the input variables used were the acoustic parameters from the spectrum and the principal components extracted from the whole spectrum. The best classification procedure used the principal components from the principal components analysis of the spectrum for probe B. In this case, the 50 wheel pieces used in this study were correctly classified. These results showed that a simple and low-cost acoustic impulse-response technique could be used to detect cheese cracks, formed at different moments of Manchego cheese maturation.

The textural and ultrasonic properties of the subcutaneous fat from five batches of dry-cured hams from animals with different genetics (Iberian, Iberian × Duroc) and type of feeding (“montanera”, concentrate feeds with different oleic acid content) were studied and related to the sensory traits (oiliness and brightness) of their biceps femoris muscle. The different genetics and feeding backgrounds found in the batches brought about differences in their ultrasonic velocities (average velocity from 4 to 20 °C ranged from 1608 to 1650 m/s) and textural parameters (maximum force at 8 °C ranged from 11 to 21 N). On average, batches with lower textural parameters had lower velocities and higher sensory scores. Ultrasonic measurements were used to carry out a discriminant analysis which allowed 78.3% of the samples to be correctly classified in the batches considered. Therefore, ultrasonic and sensory techniques could be useful in the characterization and differentiation of dry-cured hams from Iberian pigs.

The quality of frying oils covering a wide range of oil degradation and degree of unsaturation was analyzed using ultrasonic techniques. Ultrasonic velocity and attenuation decreased with temperature, and the average velocity temperature coefficients were −3.59 and −3.51 m s−1 °C−1 for monounsaturated (MUO) and polyunsaturated (PUO) oils, respectively. Velocity was linearly related to viscosity, showing higher values for PUO than for MUO. Velocity was also related to the percentage of polar compounds (R2 = 0.77 and 0.86 for PUO and MUO, respectively) and polymers (R2 = 0.86 for PUO and MUO together). The use of velocity and viscosity in a single prediction model allowed to classify 97.5% of the samples correctly, according to the 25% polar compounds limit. Therefore, ultrasonic techniques can be used to characterize thermal degradation of oils when subjected to different frying conditions, which could be useful for frying operators or inspection services., The authors acknowledge the financial support from the Ministerio de Ciencia y Tecnología (Spain) and the INIA (CAL01-077-C3-1).

Five batches of Iberian pig backfat of different breeds and with differing feeding regimes were analysed as to their fatty acid composition and textural, thermal and ultrasonic properties. The feeding regime affected the backfat composition more than the breed of the animals. The higher the oleic acid content in the feeding regime, the higher the monounsaturated fatty acid content in the samples. Ultrasonic velocities ranged from 1609 to 1631 m/s. A change in the slope of the velocity versus temperature curve was found at 6 °C, coincident with a change in the melting rate found in the differential scanning calorimetry. Discriminant analysis using ultrasonic measurements allowed 94.7% of the samples to be correctly classified in the batches considered, while the use of the fatty acids composition correctly classified 86.2% of the samples. Therefore, ultrasonic techniques could be useful in the characterization and classification of backfat samples from Iberian pigs.

Ultrasound has been used to non-destructively assess the quality of many foods such as meat, fish, vegetables and dairy products. This paper addresses the applications of low intensity ultrasonics in the cheese manufacturing processes and highlights the areas where ultrasonics could be successfully implemented in the future. The decrease of ultrasonic attenuation during the renneting process can be used to determine the optimum cut time for cheese making. The ultrasonic velocity increases during maturation for those types of cheese that become harder during this manufacturing stage, thus being an indicator of the maturity degree. Moreover, ultrasonic measurements could be linked to sensory parameters. From the ultrasonic velocity measurements at two different temperatures, it is possible to assess cheese composition, thus allowing an improvement in the quality and uniformity of cheese commercialization. In addition, in pulse-echo mode it is possible to detect cracked pieces due to abnormal fermentations and also to assess the distance of the crack from the surface.

In this paper, changes in ultrasonic properties during thermoxidation of virgin olive oil were studied. Samples of virgin olive oil were heated over different periods of time from 2 to 16 h at 200 °C. Oil degradation was characterized by means of physical and chemical changes, i.e., viscosity, color, polar compounds, polymers, and polar fatty acids. Ultrasonic measurements were carried out while the oil sample was cooled from 35 to 25 °C. It was found that velocity and attenuation measurements were related to viscosity measurements through a classical equation for viscous liquids. The ultrasonic measurements were also related to the percentages of polar compounds and polymers, which shows the feasibility of using ultrasonic properties to monitor oil quality. Nevertheless, as long as the ultrasonic measurements are temperature dependent, this variable must be controlled in order to obtain repetitive and reliable measurements. Keywords: Frying oil; polar compounds; ultrasonics; viscosity

[EN] The aim of this work was to evaluate the use of ultrasonic measurements to characterize the crystallization process and to assess the textural changes of Iberian fat and Iberian ham during cold storage. The ultrasonic velocity was measured in two types of Iberian fats (Montanera and Cebo) during cold storage (0, 2, 5, 7 and 10 ºC) and in vacuum packaged Iberian ham stored at 6ºC for 120 days. The fatty acid profile, thermal behaviour and textural properties of fat were determined. The ultrasonic velocity and textural measurements showed a two step increase during cold storage, which was related with the separate crystallization of two fractions of triglycerides. It was observed that the harder the fat, the higher the ultrasonic velocity. Likewise, Cebo fat resulted harder than Montanera due to a higher content of saturated triglycerides. The ultrasonic velocity in Iberian ham showed an average increase of 55 m/s after 120 days of cold storage due to fat crystallization. Thus, non-destructive ultrasonic technique could be a reliable method to follow the crystallization of fats and to monitor the changes in the textural properties of Iberian ham during cold storage.

4 páginas, 6 figuras, Oil is an important component of almonds and other vegetable substrates that can show an influence on human health. In this work the development and validation of an innovative, robust, stable, reliable and efficient ultrasonic system at pilot scale to assist supercritical CO2 extraction of oils from different substrates is presented. In the extraction procedure ultrasonic energy represents an efficient way of producing deep agitation enhancing mass transfer processes because of some mechanisms (radiation pressure, streaming, agitation, high amplitude vibrations, etc.). A previous work to this research pointed out the feasibility of integrating an ultrasonic field inside a supercritical extractor without losing a significant volume fraction. This pioneer method enabled to accelerate mass transfer and then, improving supercritical extraction times. To commercially develop the new procedure fulfilling industrial requirements, a new configuration device has been designed, implemented, tested and successfully validated for supercritical fluid extraction of oil from different vegetable substrates., Work supported by the National Research Project PETRI-PTR95- 075.OP.02. The authors would like to thank V.M. Acosta for his collaboration in the design of the power transducers by FEM and their development.

Ultrasonic velocity in Mahon cheese increased during maturation ranging from 1624 to 1737 m/s. A quadratic equation was used to describe this increase. This equation could be used to assess the maturation time under specific maturing conditions in order to classify the pieces in different categories. Through-transmission and pulse-echo techniques were used to detect cracks within the pieces formed by abnormal fermentations. In pulse-echo mode it was possible to detect all the cracked pieces and also to assess the distance to the surface. These ultrasonic measurements are nondestructive, allowing control over all the pieces of a batch.

The main aim of this work was to assess the influence of power ultrasound on mass transfer process during convective drying of a low porosity product submitted to different acoustic energy levels. Drying kinetics of carrot cubes (side 8.5 mm) were carried out at 40 °C and 1 m/s applying different electric power levels to the ultrasonic transducer: 0, 10, 20, 30, 40, 50, 60, 70, 80 and 90 W. Drying kinetics were modelled considering the diffusion theory. From the results, a significant (p