Computer image analysis for intramuscular fat segmentation in dry-cured ham slices using convolutional neural networks

Determination of intramuscular fat (IMF) content in dry cured meats is critical because it affects the sensory quality and consumer's acceptability. Recently, deep learning has become one of the most promising techniques in machine learning for image analysis. However, few applications in food products are found in the literature. This study presents the application of deep learning for the detection of intramuscular fat (IMF) in images of slices of dry cured ham. 8 convolutional neural networks (CNNs) have been studied and compared using segmented images (252 for training, 61 for validation and 62 for testing). The performance was compared to other simple CNNs. CNNs were able to segment IMF with an overall pixel accuracy of 0.99 and a recall and precision rates for fat near 0.82 and 0.84, respectively, using a limited number of training images. However, performance is affected by the quality of the ground truth due to the difficulty of labelling correctly pixels.info:eu-repo/semantics/acceptedVersio

Physicochemical characterisation of restructured Fenalår and safety implications of salt and nitrite reduction

There is a new trend to produce dry-cured ham from lamb in shorter times by boning the ham before salting to later obtain restructured hams that are easier to dry and slice. However, little information about the physicochemical characteristics of Norwegian Fenalårs during the process or the safety implications of their elaboration procedures is reported in the literature. The aim of this study was to characterize the colour, texture and physicochemical properties of restructured Fenalårs when using Standard Salting (SS), Salt Reduced (SR) and a Non-Nitrite Salt Reduced (NNSR) treatments. Microbiological safety implications of the elaboration process when using the different salting treatments were also assessed using predictive microbiology. To do so, sixty Fenalårs were elaborated using a Standard Salting (SS), a Salt reduced (SR) and a Non-Nitrite Salt Reduced (NNSR) treatments. Physicochemical characterization (instrumental colour and texture and Zinc Protoporphyrin content) was performed at the end of the process using thirty Fenalårs. The rest of the Fenalårs were used to characterize the product through the elaboration process (pH and aw) for the evaluation of microbiological hazards when using the different salting treatments using predictive microbiology. Results showed a significant increase in softness when reducing salt content and a decrease of redness when no nitrite was used, attributed to the formation of ZnPP content instead of nitrosylmyoglobin. In terms of risk assessment, the decrease of aw through the elaboration process reduced the growth capacity of all the microorganisms evaluated. However, microbiological safety implications in salt reduced Fenalårs are important, especially when no nitrite was added, because the considerable increase of growth potential of L. monocytogenes. The increase of growth potential of proteolytic C. botulinum is very little and no relevant effect of nitrite on growth potential of S. aureus was observed. Predictive microbiology and optimization of the process to enhance ZnPP formation can help to ensure safety and quality of salt reduced restructured Fenalårs without additives.info:eu-repo/semantics/acceptedVersio

Instrumental texture analysis on the surface of dry-cured ham to define the end of the process

The end of the elaboration process of dry-cured ham is currently decided by product weight loss and/or by an expert who carries out an evaluation of the tactile texture on the surface. The objective of this study was to define the optimal measurement conditions of an instrumental texture analysis on the surface of the dry-cured ham (ITAS), to define the end of process. 120 dry-cured hams were classified by experts into Hard (appropriate) or Soft (non-appropriate) texture groups and used to perform compression tests using different probes on three anatomical positions. Results showed that the small probe in position 2 gave the most discriminant conditions, providing representative information of the internal texture. Although classification using only weight loss was possible with an accuracy rate of 80.4 % or 66.7% depending on the weight loss, the maximum classification accuracy was obtained when using ITAS in combination with weight loss. Further studies at industrial level are needed.info:eu-repo/semantics/acceptedVersio

Effect of proteolysis index level on instrumental adhesiveness, free amino acids content and volatile compounds profile of dry-cured ham

[EN] Defective textures in dry-cured ham are a common problem that causes important economic losses in the ham industry. An increase of proteolysis during the dry-cured ham processing may lead to high adhesiveness and consumer rejection of the product. Therefore, the influence of proteolysis index (PI) on instrumental adhesiveness, free amino acids and volatile profile of dry-cured ham was assessed. Two hundred Spanish dry-cured ham units were firstly classified according to their PI: low PI ( 36%). Instrumental adhesiveness was affected by PI, showing the lowest values in the batch with low PI. Significant differences (P < 0.05) among groups were found in six amino acids: serine, taurine, cysteine, methionine, isoleucine and leucine. The content of leucine, serine, methionine, and isoleucine significantly (P < 0.05) increased as the proteolysis index rose. However, taurine and cysteine content showed an opposite behaviour, reaching the highest values in the dry-cured hams with low PI. Significant differences (P < 0.001) in the total content of volatile compounds among ham groups were observed, with the highest concentration in the batch with low PI, and decreasing the concentration as the PI increased. Regarding the different chemical families of volatiles, the hydrocarbons (the main family), alcohols, aldehydes, ketones and acids were more abundant in the hams showing the lowest PI. Esters did not show significant differences among the three batches of hams studied. The present study demonstrated that, apart from the effect on the adhesiveness, an excessive proteolysis seems to be associated with negative effects on the taste and aroma of the dry-cured ham.This research was supported by Grant RTA 2013-00030-CO3-03 from INIA (Spain). Acknowledgements to INIA for granting Cristina Perez Santaescolastica with a predoctoral scholarship. Jose M. Lorenzo is member of the MARCARNE network, funded by CYTED (ref. 116RT0503).Pérez-Santaescolástica, C.; Carballo, J.; Fulladosa, E.; Garcia-Perez, J.; Benedito Fort, JJ.; Lorenzo, J. (2018). Effect of proteolysis index level on instrumental adhesiveness, free amino acids content and volatile compounds profile of dry-cured ham. Food Research International. 107:559-566. https://doi.org/10.1016/j.foodres.2018.03.001S55956610

Texture characterization of dry-cured ham using multi energy X-ray analysis

[EN] Multi energy X-ray sensors are able to differentiate and quantify X-rays of different energies. In contrast to conventional sensors, which simply record the overall energy of the X-rays whatever the energy of x-rays is, multi energy sensors provides a spectrum of the X-rays energies, which may be differently attenuated. In this study, the feasibility of this technology to detect changes in dry-cured ham slices after inducing proteolysis was evaluated. Effect of salt and water contents on the attenuation was also studied. In addition, the classification of commercial samples according to their proteolysis index was assessed. Results showed a decrease of attenuation for increasing proteolysis induction times (p < 0.01) for all the regions of the spectrum (energy bands), but not with the same intensity, at any of the analysed acquisition conditions. Salt and water contents produced a significant (p < 0.01) effect on the attenuation. Influence of salt content was higher than that of water content, and both affected the prediction of the proteolysis index. Classification score of commercial samples exhibited a limited discrimination capacity, showing the need for more sophisticated data analysis. (C) 2018 Elsevier Ltd. All rights reserved.This work was partially supported by INIA (contract n. RTA201300030-0O3-01), Ministerio de Economia y Competitividad (PEJ2014-A34573) and CERCA programme from Generalitat de Catalunya.Fulladosa, E.; Austrich, A.; Muñoz, I.; Guerrero, L.; Benedito Fort, JJ.; Lorenzo, J.; Gou, P. (2018). Texture characterization of dry-cured ham using multi energy X-ray analysis. Food Control. 89:46-53. https://doi.org/10.1016/j.foodcont.2018.01.020S46538

Comparative proteomic profiling of myofibrillar proteins in dry-cured ham with different proteolysis indices and adhesiveness

Excessive proteolysis during dry-cured ham processing may lead to high adhesiveness and consumer dissatisfaction. The aim of this research is to identify biomarkers for proteolysis and adhesiveness. Two hundred biceps femoris porcine muscle samples from Spanish dry-cured ham were firstly evaluated for various physicochemical parameters, including their proteolysis indices and instrumental adhesiveness. Proteins of samples with extreme proteolysis indices were separated by two-dimensional electrophoresis and identified by tandem mass spectrometry (MALDI-TOF/TOF). We found that hams of higher proteolysis index had statistically significant increased adhesiveness. Proteomic analysis revealed statistically significant qualitative and quantitative differences between sample groups. Thus, protein fragments increased remarkably in samples with higher proteolysis index scores. In addition, higher proteolysis index hams showed increased degradation for a total of five non-redundant myofibrillar and sarcoplasmic proteins. However, myosin-1, α-actin and myosin-4 proteins were the biomarkers that underwent the most intense response to proteolysis and adhesiveness.info:eu-repo/semantics/acceptedVersio

Influence of high-pressure processing at different temperatures on free amino acid and volatile compound profiles of dry-cured ham

The effect of high pressure processing (HPP) (600 MPa during 6 min) at different temperatures (0, 20 and 35 °C) in dry-cured ham has been studied in order to optimize the technique and reduce its impact on chemical characteristics, which are widely related with sensorial parameters. Vacuum-packed slices from 120 dry-cured hams were used. These slices were submitted to four different treatments: without application of pressure or temperature (CO), high pressure treatment at 0 °C (HPP-0), high pressure treatment at 20 °C (HPP-20), and high-pressure treatment at 35 °C (HPP-35). The effect of the treatments on free amino acids and volatile compounds profile was evaluated. The HPP-35 treatment significantly (P < 0.001) increased the total free amino acid content (6415.63 mg/100g dry matter) when compared to the contents of the CO, HPP-0 and HPP-20 treatments (5313.16, 4787.30 and 5072.48 mg/100g dry matter, respectively). Significant differences were also found among treatments in the content of 13 individual free amino acids, and HPP-35 samples presented the highest values in 12 of them. Similarly, the total volatile compound content was influenced by temperature-assisted HPP treatments. The HPP-35 treated samples showed the highest content (78,415.27 AU × 103/g dry-cured ham) and the HPP-0 treated samples the lowest content (28,584.14 AU × 103/g dry-cured ham). No significant differences were observed between CO and HPP-20 treatments. The fractions of volatile compounds derived from lipolysis, proteolysis and microbial activity were significantly modified by the different treatments. HPP-0 samples presented lower values of alcohol and hydrocarbon contents, whereas HPP-35 samples showed higher ketone and ester contents.info:eu-repo/semantics/acceptedVersio