José Sánchez del Pulgar

Physico-chemical, textural and structural characteristics of sous-vide cooked pork cheeks as affected by vacuum, cooking temperature, and cooking time

This paper describes the influence of different factors on sous-vide cooked pork. Pork cheeks were cooked at different combinations of temperature (60°C or 80°C), time (5 or 12h) and vacuum (vacuum or air packaged). Weight losses were lower and moisture content higher in samples cooked for a shorter time (P=0.054) and at a lower temperature (P<0.001). Samples cooked at 60°C showed more lightness (L*) and redness (a*) (P<0.001). Lipid oxidation showed an interaction between cooking time and temperature (P=0.007), with higher TBARs values for samples cooked for 12h at 60°C and lower for those cooked for 12h at 80°C. Samples cooked at 80°C for 12h showed lower (P<0.05) values for most textural parameters than all the other types of samples. Vacuum packaging showed no influence on any of the studied variables. For the treatments evaluated, cooking temperature×time combination seems to be more important than vacuum packaging in the textural and colour parameters of pork cheeks.

Rapid characterization of dry cured ham produced following different PDOs by proton transfer reaction time of flight mass spectrometry (PTR-ToF-MS)

In the present study, the recently developed proton transfer reaction time of flight mass spectrometry (PTR-ToF-MS) technique was used for the rapid characterization of dry cured hams produced according to 4 of the most important Protected Designations of Origin (PDOs): an Iberian one (Dehesa de Extremadura) and three Italian ones (Prosciutto di San Daniele, Prosciutto di Parma and Prosciutto Toscano). In total, the headspace composition and respective concentration for nine Spanish and 37 Italian dry cured ham samples were analyzed by direct injection without any pre-treatment or pre-concentration. Firstly, we show that the rapid PTR-ToF-MS fingerprinting in conjunction with chemometrics (Principal Components Analysis) indicates a good separation of the dry cured ham samples according to their production process and that it is possible to set up, using data mining methods, classification models with a high success rate in cross validation. Secondly, we exploited the higher mass resolution of the new PTR-ToF-MS, as compared with standard quadrupole based versions, for the identification of the exact sum formula of the mass spectrometric peaks providing analytical information on the observed differences. The work indicates that PTR-ToF-MS can be used as a rapid method for the identification of differences among dry cured hams produced following the indications of different PDOs and that it provides information on some of the major volatile compounds and their link with the implemented manufacturing practices such as rearing system, salting and curing process, manufacturing practices that seem to strongly affect the final volatile organic profile and thus the perceived quality of dry cured ham.

PTR-MS in Italy: A Multipurpose Sensor with Applications in Environmental, Agri-Food and Health Science

Proton Transfer Reaction Mass Spectrometry (PTR-MS) has evolved in the last decade as a fast and high sensitivity sensor for the real-time monitoring of volatile compounds. Its applications range from environmental sciences to medical sciences, from food technology to bioprocess monitoring. Italian scientists and institutions participated from the very beginning in fundamental and applied research aiming at exploiting the potentialities of this technique and providing relevant methodological advances and new fundamental indications. In this review we describe this activity on the basis of the available literature. The Italian scientific community has been active mostly in food science and technology, plant physiology and environmental studies and also pioneered the applications of the recently released PTR-ToF-MS (Proton Transfer Reaction-Time of Flight-Mass Spectrometry) in food science and in plant physiology. In the very last years new results related to bioprocess monitoring and health science have been published as well. PTR-MS data analysis, particularly in the case of the ToF based version, and the application of advanced chemometrics and data mining are also aspects characterising the activity of the Italian community.

PTR-ToF-MS characterisation of roasted coffees (C. arabica) from different geographic origins

Characterisation of coffees according to their origins is of utmost importance for commercial qualification. In this study, the aroma profiles of different batches of three monoorigin roasted Coffea arabica coffees (Brazil, Ethiopia and Guatemala) were analysed by Proton-Transfer-Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS). The measurements were performed with the aid of a multipurpose autosampler. Unsupervised and supervised multivariate data analysis techniques were applied in order to visualise data and classify the coffees according to origin. Significant differences were found in volatile profiles of coffees. Principal component analysis allowed visualising a separation of the three coffees according to geographic origin and further partial least square regression-discriminant analysis classification showed completely correct predictions. Remarkably, the samples of one batch could be used as training set to predict geographic origin of the samples of the other batch, suggesting the possibility to predict further batches in coffee production by means of the same approach. Tentative identification of mass peaks aided characterisation of aroma fractions. Classification pinpointed some volatile compounds important for discrimination of coffees.

Science and Technology for New Culinary Techniques

The use of new culinary tools, methods, and ingredients in the kitchen of renowned restaurants has become common worldwide. Most of these novelties have been based in equipment, ingredients, and procedures from the food industry and food labs. There are four main topics in which this cooperation between the science and the culinary fields takes place: (a) the use of scientific knowledge about perceptions; (b) taking advantage of the scientific knowledge about food composition and properties; (c) the use of nontraditional ingredients and knowledge concerning their application to culinary uses; (d) the usage of industrial and scientific technologies that are far from traditional culinary technologies. The contribution of scientific information for the evaluation of safety issues is also of great importance for these new culinary developments, because in some cases, there is a lack of normative and basic food safety working procedures. This review deals with different aspects of some of these new tools, procedures, and ingredients, including basic scientific background, technological questions, and food safety concerns.

Effect of origin, breeding and processing conditions on the isotope ratios of bioelements in dry-cured ham.

The stable isotope ratios (SIR) of the bioelements ((2)H/(1)H, (13)C/(12)C, (15)N/(14)N, (18)O/(16)O, (34)S/(32)S) of the defatted dry matter and marbling and subcutaneous fat fractions, were assessed on 86 ham samples belonging to six different types, with the aim of ascertaining the effect of origin and production system on 11 isotopic ratios. The ham types were obtained from pigs reared in three regions, examining in every location one different production factor at two levels of expression: pig genotype (local breed vs. industrial hybrid) in Friuli (Italy), pig feeding regime (Bellota vs. Campo) in Extremadura (Spain) and ham seasoning time (mid vs. end) in Emilia (Italy). The isotopic composition of meteoric water and the dietary abundance of C(4) plants allowed to distinguish Italian PDO from Spanish hams. The contrasting treatments within the regional batches generated promising differences in SIR, potentially useful for tracing the whole ham production system, including the processing procedure.

Volatile Compounds Profile of Sous-Vide Cooked Pork Cheeks as Affected by Cooking Conditions (Vacuum Packaging, Temperature and Time)

The volatile organic compound (VOC) profile of pork cheeks as affected by the cooking conditions was investigated. Pork cheeks were cooked under different combinations of temperature (60 °C or 80 °C), time (5 or 12 h) and vacuum (vacuum or air-packaged). As a general rule, the VOCs originating from lipid degradation were positively affected by the cooking temperature and negatively by the cooking time, reaching the highest amounts in pork cheeks cooked at 80 °C during 5 h and the lowest in samples cooked at 80 °C during 12 h. On the contrary, VOCs originated from amino acids and Maillard reactions were positively affected by both factors. The proportion between lipid degradation and amino acids reactions was estimated by the hexanal/3-methylbutanal ratio, which reached its highest values in samples cooked at 60 °C during 5 h in the presence of air and the lowest values in samples cooked at 80 °C during 12 h, regardless of the vacuum status.

Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat.

Study of the volatile compounds and odor-active compounds of dry-cured Iberian ham extracted by SPME

The volatile compounds and the most odor-active compounds of dry-cured Iberian ham were investigated by extracting them using a solid phase microextraction technique with a 2 cm Carboxen/PDMS/DVB fiber. The detection frequency method was applied to estimate the potential contribution of each compound to the odor of hams. Twenty-one volatile compounds were tentatively identified for the first time in dry-cured ham by gas chromatography-mass spectrometry, and eight in dry-cured Iberian ham. Gas chromatography-olfactometry allowed the identification for the first time of six compounds not previously reported as odorants of Iberian ham, and also two odorants were newly identified in dry-cured ham. According to the detection frequency method, the most odor active compounds found were 3-methylbutanoic acid (dirty sock-like smelling), hexanal (cut grass-like odor), 3-methylbutanal (sweaty and bitter almond-like odor), 2-methyl-3-furanthiol (toasted nuts-like odor) and 1-octen-3-one (mushroom-like odor).

Immune-spaying as an alternative to surgical spaying in Iberian×Duroc females: effect on carcass traits and meat quality characteristics.

The aim of this study was to assess the effect of immune-spaying on production traits and meat quality characteristics of fresh loin (longissimus dorsi) by comparing 3 groups of Iberian×Duroc females (N=12 per batch): surgically spayed, immune-spayed and entire females. Carcass traits and physicochemical parameters, including fatty acid profile, were investigated. The only carcass trait significantly affected by castration was the ham fat thickness, where both immune-spayed and surgically spayed females showed higher values against entire females (57±9.5mm, 62±2.5mm and 51±10.1mm, respectively; p<0.05). Furthermore, there were no significant differences in the quality parameters of fresh meat. These results are important regarding animal welfare, since in Europe, there is a plan to voluntarily end the surgical castration of pigs by 2018. Therefore, with an adequate vaccination protocol, immune-spaying might represent a good alternative to surgical spaying. The reliability of immune-spaying over long periods should be evaluated.