Comparative effect of different cooking methods on the physicochemical and sensory characteristics of high pressure processed marinated pork chops

peer-reviewedThe objective of this study was to assess the effect of griddle and steam cooking on the physicochemical and sensory characteristics of high pressure processed (HPP) piri-piri marinated pork chops (MPC). Raw MPC that were HPP at 400 MPa had higher (P < 0.05) marinade absorption compared to untreated samples. After cooking, griddled MPC were significantly (P < 0.05) darker, less red, less yellow, tougher and had higher cook loss compared to steam cooked samples. The appearance of the griddled MPC was preferred while the texture, tenderness, juiciness and overall sensory acceptability (OSA) were preferred in steam cooked MPC. The increased marinade absorption in MPC that were HPP modified the fatty acid composition resulting in increased (P < 0.05) levels of oleic acid (C18:1c). Steam cooked MPC had a lower (P < 0.05) n-6: n-3 PUFA ratio and were preferred by the sensory panel compared to griddled MPC. Overall, from the cooking methods assessed steam cooking was the best cooking method for untreated and MPC that were HPP. Industrial relevance: Processed meat manufacturers are constantly looking for new ways to increase yield, safety and shelf life of meat products. While high pressure processing (HPP) of raw meat has been shown to increase the safety and shelf life of these products; however, negative effects on the physicochemical characteristics of raw meat products have been reported. For example, HPP of raw meat products causes a whitening effect which may negatively affect consumers' acceptance of these products. In this study, we used a novel approach (a combination of HPP, marinade and a mix of organic acids Inbac™) which showed great potential not only for enhancing the yield of marinated pork chops but also enhancement of the sensory properties, safety and shelf life and particularly the piri-piri marinade masked the discoloration of raw pork meat caused by HPP. This study also provides consumers, retailers and caterers with information on how to best prepare HPP meat products and showed that steam cooked HPP marinated pork chops had the best physicochemical and sensory characteristics compared to griddled marinated pork chops

Development of active, nanoparticle, antimicrobial technologies for muscle-based packaging applications

Fresh and processed muscle-based foods are highly perishable food products and packaging plays a crucial role in providing containment so that the full effect of preservation can be achieved through the provision of shelf-life extension. Conventional packaging materials and systems have served the industry well, however, greater demands are being placed upon industrial packaging formats owing to the movement of muscle-based products to increasingly distant markets, as well as increased customer demands for longer product shelf-life and storage capability. Consequently, conventional packaging materials and systems will have to evolve to meet these challenges. This review presents some of the new strategies that have been developed by employing novel nanotechnological concepts which have demonstrated some promise in significantly extending the shelf-life of muscle-based foods by providing commercially-applicable, antimicrobially-active, smart packaging solutions. The primary focus of this paper is applied to subject aspects, such as; material chemistries employed, forming methods utilised, interactions of the packaging functionalities including nanomaterials employed with polymer substrates and how such materials ultimately affect microbes. In order that such materials become industrially feasible, it is important that safe, stable and commercially-viable packaging materials are shown to be producible and effective in order to gain public acceptance, legislative approval and industrial adoption

In vitro cytotoxicity of water soluble silver (Ag) nanoparticles on HaCat and A549 cell lines

The wide range of applications of silver nanoparticles (AgNPs) in commercial products, including food packaging, has encouraged researchers to come up with novel preparation methods for the production of these robust materials. The methods resulting in the formation of NPs for such commercial applications clearly demand a good accounting of their toxicity aspects to humans as well as the environment. We herein present a chemical preparation method for the production of size- and shape-defined AgNPs and investigate the impact of these nanoparticles on HaCat and A549 cell lines. Findings show that lung cells (A549) are more sensitive than skin cells (HaCat) to Ag induced toxicity, evident by the significantly (p<0.05) reduced LC50 for all NPs under study. The current investigation showed that the extent of surface capping agent (citrate) and size influenced the cell toxicity, where a lesser surface coverage (zeta potential, ζ, -27.7 mV) and smaller size (~17 nm) enhanced the toxicity compared to comparatively bigger particles (~39 nm) with higher surface coverage (ζ, -47.3 mV). The size- and shape-defined particles such as triangles which have proven useful for many applications, due to their high energy/high field edges, were found to be less toxic against biological cell lines and therefore may have potential to be used in food packaging applications as reservoirs of silver ions. A striking difference in cell line toxicity within such a small size window clearly demonstrates the vital roles played by the smaller size, difference in shape and lesser surface coverage in defining a higher passive cell membrane diffusion followed by silver dissolution inside cell cytoplasm increasing cytotoxicity

Nanosize and shape effects on antimicrobial activity of silver using morphology-controlled nanopatterns by block copolymer fabrication

The activity of silver nanomaterials as an antimicrobial is well-known with authors noting strong size and shape effects. This paper explores if the antimicrobial activity relates to unique size-related properties of the nanodimensioned materials or a more physical effect. Staphylococcus aureus and Pseudomonas aeruginosa were explored as test bacteria. They can cause serious human infections and are becoming resistant to pharmaceutical antimicrobials. Silver nanopatterns on a substrate surface were used as the antimicrobial agent. We demonstrate a cost-effective facile route to fabricate a well-ordered, periodic, and dimension-controlled silver lines and dots pattern on a substrate surface. This allowed precise definition of the silver materials to explore size and shape effects. Polystyrene-b-poly(ethylene oxide) (PS-b-PEO) block copolymer (BCP) microphase separated thin films were used as structural templates. Well-ordered PS-b-PEO thin film with vertical and parallel oriented PEO cylinders was achieved by a solvent vapor annealing approach through careful optimization of experimental parameters. A selective inclusion method (into one block of the BCP) of silver nitrate was used to generate the silver nanopatterns. Spin coating precursor-ethanol solution and subsequent UV/ozone treatment produce silver nanopattern arrays. They exhibited a significant growth-inhibitory effect on Staphylococcus aureus and Pseudomonas aeruginosa biofilms. However, data suggest this is associated with high surface area rather than a unique nanodimension related property change dictated by size or shape

Kinetic desorption models for the release of nanosilver from an experimental nanosilver coating on polystyrene food packaging

To predict the kinetic desorption of silver from an experimental nanosilver coated polystyrene food packaging material into food simulants (0, 1, 2 and 3% acetic acid (HAc) in distilled water (dH2O)) at 4 temperatures (10, 20, 40 and 70 °C), 5 sorption models were examined for their performance. A pseudo-second order kinetic sorption model was found to provide the best prediction of an unseen desorption validation dataset with R2 = 0.90 and RMSE = 3.21. Poor predictions were witnessed for desorption at 70 °C, potentially due to re-adsorption of the silver back onto the polystyrene substrate, as shown in the kinetic migration experiments. Similarly, the temperature dependence of the desorption rate constant was satisfactorily described using the Arrhenius equation with the exception of the 70 °C scenario. The use of sorption models identified scenarios that may limit human exposure to nanosilver migrating from this experimental nanocoating, i.e. low temperature applications. Industrial relevance: The use of antimicrobial packaging has the potential to reduce food spoilage and risk from pathogenic microorganisms while reducing food waste by extending the shelf life of food products. Coating of antimicrobial silver nanoparticles (AgNPs) to polymer surfaces is a highly advantageous technology as microbial contamination predominantly occurs on the surface of fresh and processed food products. However, uncertainty related to the potential release of nanoparticles from food packaging materials, subsequent potential human exposure and toxicology is a barrier to the uptake of these novel materials. In the European Union, where the safety assessment of these materials is stringent, mathematical models used to predict the worst case migration of nanoparticles from food packaging materials have supported the acceptance of some nanomaterials for use in food packaging. The performance of a number of desorption models was evaluated to predict the release of AgNPs from AgNP coated polystyrene. The model identified factors that influenced migration and possible industrial applications for the developed material to minimise human exposure. The study highlights the potential benefits of using predictive models to assess migration of NPs from polymers into food simulants instead of time consuming and expensive migration studies

Improving marinade absorption and shelf life of vacuum packed marinated pork chops through the application of high pressure processing as a hurdle

peer-reviewedThe objective of this study was to determine the efficacy of HPP to accelerate marinade (piri-piri) absorption in pork chops and to study the effects on the physicochemical, sensory and microbiological characteristics during storage. HPP (300 MPa, 400 MPa or 500 MPa) and organic acids Inbac™ (0.3%) were used as hurdles to extend the shelf life. The results showed that HPP ≥ 400 MPa increased (P < 0.05) the marinade absorption which enhanced the flavour acceptability of the marinated pork chops. The piri-piri marinade masked the discolouration caused by HPP and increased (P < 0.05) the tenderness of the pork chops over storage. From the microbiological point of view, HPP at 300, 400 or 500 MPa and Inbac™ (0.3%) extended (P < 0.05) the shelf life by 16, 22 and 29 days, respectively. The results highlighted the potential of combined effects of HPP and antimicrobial Inbac™ to accelerate marinade absorption and extend the shelf life of marinated pork chops

Surface attachment of active antimicrobial coatings onto conventional plastic-based laminates and performance assessment of these materials on the storage life of vacuum packaged beef sub-primals

Two antimicrobial coatings, namely Sodium octanoate and Auranta FV (a commercial antimicrobial composed of bioflavonoids, citric, malic, lactic, and caprylic acids) were used. These two antimicrobials were surface coated onto the inner polyethylene layer of cold plasma treated polyamide films using beef gelatin as a carrier and coating polymer. This packaging material was then used to vacuum pack beef sub-primal cuts and stored at 4 °C. A control was prepared using the non-coated commercial laminate and the same vacuum packaged sub-primal beef cuts. During storage, microbial and quality assessments were carried out. Sodium octanoate treated packages significantly (p < 0.05) reduced microbial counts for all bacteria tested with an increase of 7 and 14 days, respectively compared to control samples. No significant effect on pH was observed with any treatment. The results suggested that these food grade antimicrobials have the potential to be used in antimicrobial active packaging applications for beef products

Starch-gelatin antimicrobial packaging materials to extend the shelf life of chicken breast fillets

[EN] Antimicrobial starch:gelatin (1:1) films containing N-¿-lauroyl-l-arginine ethyl ester monohydrochloride (LAE) (10 % wt.) were used as food contact active layers in chicken breast fillets vacuum-packaged in polyamide/polyethylene pouches. Active layers were thermoprocessed (TP) or cast (OC) on the plastic film. Oxidized starch was used in OC coatings. Packaged chicken breast samples were stored at 4¿°C and their physicochemical properties (pH, colour and lipid oxidation) and microbial quality were analysed throughout storage. Both TP and OC films significantly (p¿<¿0.05) extended the shelf life of chicken breast fillets compared to control samples. The starch oxidation reaction in OC films promoted the formation of Maillard reaction compounds in the starch-gelatine blends, which enhanced the antimicrobial effectiveness of the OC films, but also promoted oxidative processes. This greatly affected the pH and colour parameters in OC packaged samples. Therefore, TP blend films containing LAE are recommended since they effectively extended the shelf life of chicken breast fillets without affecting the meat oxidation.The authors acknowledge the financial support provided by Ministerio de Economia y Competividad (Projects AGL2016-76699-R and AGL2013-42989-R). Olga Moreno Marro also thanks the Ministerio de Educacion, Cultura y Deporte for the FPU 2012-1121 grant.Moreno Marro, O.; Atarés Huerta, LM.; Chiralt, A.; Cruz-Romero, MC.; Kerry, J. (2018). Starch-gelatin antimicrobial packaging materials to extend the shelf life of chicken breast fillets. LWT - Food Science and Technology. 97:483-490. https://doi.org/10.1016/j.lwt.2018.07.005S4834909

Antimicrobial and antioxidant activities of commercially available essential oils and their oleoresins

P. 221-233Entidades Financiadoras: Junta de Castilla y León” (Proyecto LE331A12-2) y Universidad de León (Proyecto ULE2010-6) The objectives of this study were to evaluate and compare in vitro antibacterial and antioxidant activities of commercially available oregano, rosemary, sage and thyme essential oils (EOs) against their corresponding oleoresins (ORs) for potential application in food packaging systems. Thyme EO showed the best antimicrobial activity against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas fluorescens (MIC values ranging 0.4±0.1 - 8.7±2.3 mg/mL). Overall, the antimicrobial efficacy of thyme and oregano EOs was found to be higher than that observed for their ORs. Additionally, these ORs did not exhibit better antioxidant properties when compared with their EOs, providing 90% lower antiradical activity and without significant differences in reducing power. The results suggested that commercially available thyme and oregano EOs could be used effectively as hurdle against food-borne pathogens and spoilage bacteria, as well as in terms of preventing lipid oxidation in food

Shelf life extension of vacuum-packed salt reduced frankfurters and cooked ham through the combined application of high pressure processing and organic acids

The objective of this study was to assess the efficacy of a combination of high pressure processing (HPP) and a mix of organic acids Inbac™ as hurdles to extend the shelf life of previously optimised sensory accepted frankfurters and cooked ham with significantly (P < 0.05) lower salt content. The optimum parameters for the manufacture of low-salt frankfurters were; Salt replacer Artisalt™ (48%), HPP (580 MPa) and Inbac™ (0.3%) and for manufacture of low-salt cooked ham the optimum parameters were; Salt replacer Artisalt™, HPP (535 MPa) and Inbac™ (0.3%). Physicochemical changes (P < 0.05) occurred over storage time; however, the sensory acceptability did not change significantly. From the microbiological point of view, the results indicated that the hurdles (HPP and Inbac™) applied in the manufacture of low-salt processed meat products extended (P < 0.05) the shelf-life of low-salt frankfurters by 51% and low-salt cooked ham by 97%, compared to control samples which contained full salt content. These results highlight the potential use of the hurdle strategy for extending the shelf-life and safety of low-salt processed meat products