• Antioxidant active packaging systems to extend the shelf life of sliced cooked ham

      Pateiro, Mirian; Domínguez, Rubén; Bermúdez, Roberto; Munekata, Paulo E.S.; Zhang, Wangang; Gagaoua, Mohammed; Lorenzo, José M.; INIA-MINECO; Axencia Galega de Innovación; CYTED; et al. (Elsevier BV, 2019-11)
      The effectiveness of active packaging systems with green tea extract and oregano essential oil was checked for their use in sliced cooked ham. Three packaging systems were evaluated: i) control group without active film, ii) ATGT packed with active film of green tea extract (1%) and iii) ATRX with a mixture of green tea extract and oregano essential oil (1%). The evolution of microbiological, physicochemical (pH, aw, colour and lipid oxidation) and sensory attributes were analysed after 0, 7, 14 and 21 days of refrigerated storage. Microbial populations were below the limits established by the European Regulations (106 UFC/g). The samples packed with ATGT showed the better antimicrobial activity against total viable counts (TVC) and lactic acid bacteria (BAL), while lower counts of Brochothrix thermosphacta was observed in ATRX film (1.48 vs. 1.78 and 2.59 UFC/g for ATRX vs. ATGT and CON, respectively). Regarding colour, low differences were found between the samples packaged with active and control films. Unlike L*, a* and b* parameters showed a progressive diminution throughout the storage in all batches, being the films that contained green tea (ATGT) were the ones that showed the less discolouration at the end of storage (8.86 vs. 8.63 and 7.50 for ATGT vs. CON and ATRX, respectively). The low fat content of this type of product and the use of anaerobic atmosphere for the packaging of cooked ham did not allow to show an antioxidant effect on lipid oxidation (values below 0.15 mg MDA/kg). Finally, the use of ATGT and ATRX did not suppose a modification of the sensorial attributes of the product, being acceptance scores under the acceptance limit during the whole display.
    • A Comprehensive Review on Lipid Oxidation in Meat and Meat Products

      Domínguez, Rubén; Pateiro, Mirian; Gagaoua, Mohammed; Barba, Francisco J.; Zhang, Wangang; Lorenzo, José M. (MDPI AG, 2019-09-25)
      Meat and meat products are a fundamental part of the human diet. The protein and vitamin content, as well as essential fatty acids, gives them an appropriate composition to complete the nutritional requirements. However, meat constituents are susceptible to degradation processes. Among them, the most important, after microbial deterioration, are oxidative processes, which affect lipids, pigments, proteins and vitamins. During these reactions a sensory degradation of the product occurs, causing consumer rejection. In addition, there is a nutritional loss that leads to the formation of toxic substances, so the control of oxidative processes is of vital importance for the meat industry. Nonetheless, despite lipid oxidation being widely investigated for decades, the complex reactions involved in the process, as well as the different pathways and factors that influenced them, make that lipid oxidation mechanisms have not yet been completely understood. Thus, this article reviews the fundamental mechanisms of lipid oxidation, the most important oxidative reactions, the main factors that influence lipid oxidation, and the routine methods to measure compounds derived from lipid oxidation in meat.
    • Evaluation of the Antioxidant and Antimicrobial Activities of Porcine Liver Protein Hydrolysates Obtained Using Alcalase, Bromelain, and Papain

      Borrajo, Paula; Pateiro, Mirian; Gagaoua, Mohammed; Franco, Daniel; Zhang, Wangang; Lorenzo, José Manuel; INIA; RTA 2017-00024-CO4-04 (MDPI AG, 2020-03-27)
      In order to make the by-products generated from the porcine industry more valuable, pig livers were used in this trial to obtain protein hydrolysates. Three proteases (alcalase, bromelain, and papain) were utilized for enzymatic hydrolysis with two different durations, 4 and 8 hours. Ultrafiltration process was used for the recovery of the extracts, employing three different membrane pore sizes (30, 10, and 5 kDa). The porcine livers contained considerable amounts of protein (19.0%), considering they are almost composed of water (74.1%). The antioxidant activity of the obtained hydrolysates was investigated using four antioxidant methods (2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2-2′-Azino-di-[3-ethylbenzthiazoline sulfonate] (ABTS) radical scavenging activity, ferric reducing antioxidant power assay (FRAP), and oxygen radical absorbance capacity assay (ORAC)). Antibacterial properties were also measured against Gram-negative and Gram-positive bacteria. Results indicated that the three studied factors (type of enzyme, membrane pore size, and time) significantly affected the parameters evaluated. Hydrolysates obtained at 8 hours with alcalase had the best antioxidant properties. The 30 kDa alcalase extracts exhibited the highest DPPH (562 µg Trolox/g), FRAP (82.9 µmol Fe2+/100 g), and ORAC (53.2 mg Trolox/g) activities, while for ABTS the 10 kDa alcalase showed the higher values (1068 mg ascorbic acid/100 g). Concerning the antibacterial activity, 30 kDa hydrolysates obtained with bromelain for 4 hours exhibited the highest antimicrobial capacity, providing an inhibition of 91.7%.
    • Inclusion of Healthy Oils for Improving the Nutritional Characteristics of Dry-Fermented Deer Sausage

      Vargas-Ramella, Márcio; Munekata, Paulo E. S.; Gagaoua, Mohammed; Franco, Daniel; Campagnol, Paulo C. B.; Pateiro, Mirian; Barretto, Andrea Carla da Silva; Domínguez, Rubén; Lorenzo, José M.; CYTED; et al. (MDPI AG, 2020-10-18)
      The influence of partial replacement of animal fat by healthy oils on composition, physicochemical, volatile, and sensory properties of dry-fermented deer sausage was evaluated. Four different batches were manufactured: the control was formulated with animal fat (18.2%), while in the reformulated batches the 50% of animal fat was substituted by olive, canola, and soy oil emulsions immobilized in Prosella gel. The reformulation resulted in a decrease of moisture and fat contents and an increase of protein and ash amount. Moreover, reformulated sausages were harder, darker, and had higher pH values. This fact is related to the lower moisture content in these samples. As expected, the fatty acid composition was changed by the reformulation. The use of soy and canola oils increased polyunsaturated fatty acids and omega-3 content and decreased n-6/n-3 ratio and saturated fatty acids. Thus, the use of these two oils presented the best nutritional benefits. The changes observed in the fatty acids reflected the fatty acid composition of the oils employed in the emulsions. Regarding volatile compounds (VOC), the replacement of animal fat by healthy emulsion gels increased the content of both total VOC and most of individual VOC. However, the lipid-derived VOC did not show this trend. Generally speaking, the control samples presented similar or higher VOC derived from lipid oxidation processes, which could be related to the natural antioxidant compounds present in the vegetable oils. Finally, all reformulated sausages presented higher consumer acceptability than control samples. In fact, the sausage reformulated with soy oil emulsion gel was the most preferred. Thus, as a general conclusion, the reformulation of deer sausages with soy emulsion gel improves both composition and sensory quality of the final product, which could be an excellent strategy to the elaboration of healthy fermented sausages.