Effect of high-pressure processing on characteristics of flexible packaging for foods and beverages

Pilot Scale Assessment of High-Pressure Processing (HPP) to Enhance Microbiological Quality and Shelf Life of Fresh Ready-to-Eat (RTE) Blue Crab Meat

Blue crab (Callinectes sapidus) is a highly valuable wild fishery species of crab native to the waters of the western Atlantic Ocean and the Gulf of Mexico. The annual commercial production of live blue crabs is approximately 50,000 metric tons with a dockside value of USD 200 million. Presently the US blue crab processing industry sells crab meat in three basic forms: fresh crab meat, pasteurized crab meat, and frozen crab meat. By far "Fresh" is the most desirable form of crab meat. However, fresh crab meat has a limited shelf life. This study evaluated the effects of high-pressure processing (HPP) on enhancing the microbiological quality and shelf life of blue crab meat. Live blue crabs were pressure-cooked in a retort (≥115 °C for 4-6 min). The crab meat was handpicked, packed in plastic containers with seals, subjected to HPP treatment, and stored at 4 °C. Container integrity and water leakage issues were examined by observation in addition to weight comparison before and after HPP treatment; the shelf life of crab meat with and without HPP treatments was examined via microbiological tests and sensory evaluations. Results show that polypropylene containers sealed with 10K OTR (oxygen transmission rate) film could withstand high pressure without water leakage issues; HPP treatment at 600 MPa for 3 min could extend the shelf life of fresh, cooked, and handpicked crab meat from 6 days to 18 days based on the strictest APC (aerobic plate account) limit (APC ≤ 100,000 CFU/g). The sensory quality of the HPP-treated crab meat was well accepted throughout the 3-week storage period. The results support the use of HPP as an effective non-thermal processing technology to enhance the microbiological quality and extend the shelf life of fresh RTE blue crab meat.

Effect of High-Pressure Treatments on the Properties of Food Packaging Materials with or without Antimicrobials

The aim of this research work was the comparative study of the different properties of interest in the case of plastic materials for food use before and after being subjected to treatment by high hydrostatic pressure (HHP) as well as the impact of additivation with antimicrobials. This method of food preservation is currently on the rise and is of great interest because it is possible to extend the shelf life of many foods without the need for the use of additives or thermal processing, as is the case with other preservation methods currently used. The effects of HHP treatment (680 MPa for 8 min) on plastic materials commonly used in the food industry were studied. These materials, in sheet or film form, were polyethylene (PE), polyethylene terephthalate (PET), polystyrene (PS), multilayer polyethylene terephthalate-ethylene-vinyl alcohol copolymer-polyethylene (PET-EVOH-PE), multilayer polyethylene-polyethylene terephthalate (PE-PET), polyvinyl chloride aluminum (PVC-AL), and polylactic acid (PLA), which were provided by manufacturing companies in the sector. PE, PP, and PLA activated with tyrosol, zinc oxide, or zinc acetate were also tested. The phenomena and properties, such as overall migration, thermal behavior, oxygen barrier, and physical properties were analyzed before and after the process. The results show that the HHP process only slightly affected the properties of the materials. After pressurization, oxygen permeability increased greatly in PVC-AL (from 7.69 to 51.90) and decreased in PLA (from 8.77 to 3.60). The additivation of the materials caused a change in color and an increase in oxygen permeability. The additivated PE and PP showed migration values above the legal limit for certain simulants. The HHP treatment did not greatly affect the mechanical properties of the additivated materials. The main increases in the migration after HHP treatment were observed for PE activated with tyrosol or zinc oxide and for PS activated with zinc oxide. Activated PLA performed the best in the migration studies, irrespective of the HHP treatment. The results suggest that activated PLA could be used in HHP food processing as an inner antimicrobial layer in contact with the food packed in a container with the desired oxygen permeability barrier.

Effect of Non-Thermal Food Processing Techniques on Selected Packaging Materials

In the last decade both scientific and industrial community focuses on food with the highest nutritional and organoleptic quality, together with appropriate safety. Accordingly, strong efforts have been made in finding appropriate emerging technologies for food processing and packaging. Parallel to this, an enormous effort is also made to decrease the negative impact of synthetic polymers not only on food products (migration issues) but on the entire environment (pollution). The science of packaging is also subjected to changes, resulting in development of novel biomaterials, biodegradable or not, with active, smart, edible and intelligent properties. Combining non-thermal processing with new materials opens completely new interdisciplinary area of interest for both food and material scientists. The aim of this review article is to give an insight in the latest research data about synergies between non-thermal processing technologies and selected packaging materials/concepts.

High-pressure pasteurization of low-acid chilled ready-to-eat food

The working population growth have created greater consumer demand for ready-to-eat (RTE) foods. Pasteurization is one of the most common preservation methods for commercial production of low-acid RTE cold-chain products. Proper selection of a pasteurization method plays an important role not only in ensuring microbial safety but also in maintaining food quality during storage. Better retention of flavor, color, appearance, and nutritional value of RTE products is one of the reasons for the food industry to adopt novel technologies such as high-pressure processing (HPP) as a substitute or complementary technology for thermal pasteurization. HPP has been used industrially for the pasteurization of high-acid RTE products. Yet, this method is not commonly used for pasteurization of low-acid RTE food products, due primarily to the need of additional heating to thermally inactivate spores, coupled with relatively long treatment times resulting in high processing costs. Practical Application: Food companies would like to adopt novel technologies such as HPP instead of using conventional thermal processes, yet there is a lack of information on spoilage and the shelf-life of pasteurized low-acid RTE foods (by different novel pasteurization methods including HPP) in cold storage. This article provides an overview of the microbial concerns and related regulatory guidelines for the pasteurization of low-acid RTE foods and summarizes the effects of HPP in terms of microbiology (both pathogens and spoilage microorganisms), quality, and shelf-life on low-acid RTE foods. This review also includes the most recent research articles regarding a comparison between HPP pasteurization and thermal pasteurization treatments and the limitations of HPP for low-acid chilled RTE foods.

Effect of High-Pressure Processing on the Packaging Properties of Biopolymer-Based Films: A Review

Suitable packaging material in combination with high-pressure processing (HPP) can retain nutritional and organoleptic qualities besides extending the product’s shelf life of food products. However, the selection of appropriate packaging materials suitable for HPP is tremendously important because harsh environments like high pressure and high temperature during the processing can result in deviation in the visual and functional properties of the packaging materials. Traditionally, fossil-based plastic packaging is preferred for the HPP of food products, but these materials are of serious concern to the environment. Therefore, bio-based packaging systems are proposed to be a promising alternative to fossil-based plastic packaging. Some studies have scrutinized the impact of HPP on the functional properties of biopolymer-based packaging materials. This review summarizes the HPP application on biopolymer-based film-forming solutions and pre-formed biopolymer-based films. The impact of HPP on the key packaging properties such as structural, mechanical, thermal, and barrier properties in addition to the migration of additives from the packaging material into food products were systemically analyzed. HPP can be applied either to the film-forming solution or preformed packages. Structural, mechanical, hydrophobic, barrier, and thermal characteristics of the films are enhanced when the film-forming solution is exposed to HPP overcoming the shortcomings of the native biopolymers-based film. Also, biopolymer-based packaging mostly PLA based when exposed to HPP at low temperature showed no significant deviation in packaging properties indicating the suitability of their applications. HPP may induce the migration of packaging additives and thus should be thoroughly studied. Overall, HPP can be one way to enhance the properties of biopolymer-based films and can also be used for packaging food materials intended for HPP.

Ifs and buts of non-thermal processing technologies for plant-based drinks' bioactive compounds

Vegetables and fruits contain a variety of bioactive nutrients and non-nutrients that are associated with health promotion. Consumers currently demand foods with high contents of healthy compounds, as well as preserved natural taste and flavour, minimally processed without using artificial additives. Processing alternatives to be applied on plant-based foodstuffs to obtain beverages are mainly referred to as classical thermal treatments that although are effective treatments to ensure safety and extended shelf-life, also cause undesirable changes in the sensory profiles and phytochemical properties of beverages, thus affecting the overall quality and acceptance by consumers. As a result of these limitations, new non-thermal technologies have been developed for plant-based foods/beverages to enhance the overall quality of these products regarding microbiological safety, sensory traits, and content of bioactive nutrients and non-nutrients during the shelf-life of the product, thus allowing to obtain enhanced health-promoting beverages. Accordingly, the present article attempts to review critically the principal benefits and downsides of the main non-thermal processing alternatives (High hydrostatic pressure, pulsed electric fields, ultraviolet light, and ultrasound) to set up sound comparisons with conventional thermal treatments, providing a vision about their practical application that allows identifying the best choice for the sectoral industry in non-alcoholic fruit and vegetable-based beverages.

Genetic Basis of High-Pressure Tolerance of a Vibrio parahaemolyticus Mutant and Its Pathogenicity

Foodborne pathogens with high-pressure processing (HPP) tolerance and their pathogenicity have gained considerable attention in the field of food safety. However, tolerance to pressure treatment varies among microorganisms and growth phases, and the mechanism by which Vibrio parahaemolyticus can become tolerant of HPP is currently not known. In this study, 183 strains of V. parahaemolyticus were isolated from seafood products, and one strain, C4, carried a thermostable direct hemolysin (tdh) gene. A strain, N11, which was acquired from the C4 strain through adaptive laboratory evolution under HPP stress, could tolerate up to 200 MPa for 10 min. Compared with the C4 strain, the catalase and Na⁺/K⁺-ATPase activities in N11 strain were increased by about 2–3 times, and the cells maintained an intact cell membrane structure under HPP treatment. As shown by murine infection trials, the C4 and N11 strains impacted the physiological activities of mice and damaged liver and spleen cells. Comparative genomic analysis showed that 19 nucleotides were mutated in the N11 strain, which led to sustained high expression of mlaC and mlaD genes in this strain. Knockout of these genes confirmed that they were involved in the high-pressure stress response, and also related to pathogenicity of V. parahaemolyticus. Thereby, our findings revealed a HPP tolerance mechanism of V. parahaemolyticus, and the high-pressure-tolerant strain still retained pathogenicity in mice with skin and fur pleating and lethargy, indicating the pressure-tolerant foodborne pathogens present health risks.

Influence of Emerging Technologies on the Utilization of Plant Proteins

Protein from plant sources is claimed alternatives to animal sources in the human diet. Suitable protein sources need high protein digestibility and amino acid bioavailability. In terms of protein functionality and food applications, they also need high-quality attributes, such as solubility, gelling, water- and oil-holding capacities, emulsifying, and foaming. Thermal processing can improve the nutritional quality of plants with some disadvantages, like reducing the assimilation of micronutrients (vitamins and minerals). Emerging technologies-such as ultrasound, high-pressure, ohmic heating, microwave, pulsed electric field, cold plasma, and enzymatic processes-can overcome those disadvantages. Recent studies demonstrate their enormous potential to improve protein techno-functional properties, protein quality, and decrease protein allergenicity. However, the literature lacks a broader evaluation, including protein digestibility, industrial-scale optimization, and exploring applications to these alternative protein sources.

Case Study of Municipal Waste and Its Reliance on Reverse Logistics in European Countries

The authors have examined municipal waste, its components and their integration with reverse logistics processes. Background: The theoretical part begins with a definition of municipal waste. Later, the integration between municipal waste and reverse logistics is provided, including presentation of the hierarchy of qualitative methods and models. Methods: The authors constructed a correlation matrix and applied a dynamic regression model to identify that the level of municipal waste impacts recycling of biowaste which demands reverse logistics. Results: The authors provided a dynamic regression model which could be applied for forecasting the size of recycled municipal waste into biowaste indicated in European Union countries. Conclusions: The variety of components in municipal waste prevents the increase of the recycling rates and has to be changed to ones that have higher recycling rates.

Recent advances and future perspective of essential oils in control Colletotrichum spp.: A sustainable alternative in postharvest treatment of fruits

The world population growth has raised concerns about food security. Agricultural systems are asked to satisfy a growing demand for food with increasingly limited resources, and simultaneously still must reduce the impacts on the environment. This scenario encourages the search for safe and sustainable production strategies. Reducing losses in the production process can be one of the main ways to guarantee food safety. In fruticulture, it is estimated that more than 50% of the production can be lost between harvest and the final consumer due to postharvest diseases caused by phytopathogenic fungi. The fungi of the genus Colletotrichum are opportunistic and are associated with several diseases, being the anthracnose the most relevant in terms of the quality and yield losses in fruit species around worldwide. To control these diseases, the use of synthetic fungicides has been the main instrument utilized, however, because of their phytotoxicity to human health, the environment, and strong selection pressure imposed by continuous applications, the fungicides have caused resistance in the pathogen populations. So reducing the excessive application of these products is indispensable for human health and for sustainable Agriculture. Towards this purpose, research has been carried out to identify the phytopathological potentiality of essential oils (EOs) extracted from plants. Therefore, this review aims to contribute to the formation of knowledge bases, about the discoveries, recent advances, and the use of EOs as a strategy to alternatively control fungal disease caused by Colletotrichum spp. in postharvest fruits. Here, we provide valuable information exploring the application potential of essential oils as commercially useful biorational pesticides for food preservation, contributing to sustainable production and global food security.

Benefits and effectiveness of high pressure processing on cheese: a ricotta case study

Today High Pressure Processing (HPP) is receiving interest thanks to its ability to stabilize foods preserving nutritional and sensorial characteristics. This work applies HPP on nutrient ricottas created in the Parmigiano Reggiano area and demonstrates not only its benefits, but also disadvantages, testing different pressures and packaging. Moreover, the ability of HPP to prolong the lag phase and reduce the maximum growth rate of bacteria is illustrated with a mathematical model. Results show the influence of HPP parameters on microbial growth, volatile organic compounds, syneresis, softness and colour, and demonstrate that not all packaging are suitable for the treatment. Obtained data highlight the effectiveness of HPP, which results the best stabilization method to sell safe and nutritive ricottas on the market with a long shelf life. Of course, the work can be a starting point for food companies who want to test an innovative and promising non-thermal technology.

Revisiting Non-Thermal Food Processing and Preservation Methods-Action Mechanisms, Pros and Cons: A Technological Update (2016-2021)

The push for non-thermal food processing methods has emerged due to the challenges associated with thermal food processing methods, for instance, high operational costs and alteration of food nutrient components. Non-thermal food processing involves methods where the food materials receive microbiological inactivation without or with little direct application of heat. Besides being well established in scientific literature, research into non-thermal food processing technologies are constantly on the rise as applied to a wide range of food products. Due to such remarkable progress by scientists and researchers, there is need for continuous synthesis of relevant scientific literature for the benefit of all actors in the agro-food value chain, most importantly the food processors, and to supplement existing information. This review, therefore, aimed to provide a technological update on some selected non-thermal food processing methods specifically focused on their operational mechanisms, their effectiveness in preserving various kinds of foods, as revealed by their pros (merits) and cons (demerits). Specifically, pulsed electric field, pulsed light, ultraviolet radiation, high-pressure processing, non-thermal (cold) plasma, ozone treatment, ionizing radiation, and ultrasound were considered. What defines these techniques, their ability to exhibit limited changes in the sensory attributes of food, retain the food nutrient contents, ensure food safety, extend shelf-life, and being eco-friendly were highlighted. Rationalizing the process mechanisms about these specific non-thermal technologies alongside consumer education can help raise awareness prior to any design considerations, improvement of cost-effectiveness, and scaling-up their capacity for industrial-level applications.

Essential oils as additives in active starch-based food packaging films: A review

The production of sustainable food packaging from renewable sources represents a prominent alternative to the use of petrochemical-based plastics. For example, starch remains one of the more closely studied replacement options due to its broad availability, low cost and significant advances in improving properties. In this context, essential oils as additives fulfil a key role in the manufacture of renewable active packaging with superior performances. In this review, a comprehensive summary of the impact of adding essential oils to the starch-based films is provided. After a brief introduction to the fundamental concepts related to starch and essential oils, details on the most recent advances in obtaining active starch-based films are presented. Subsequently, the effects of essential oils addition on the structure-property relationships (from physicochemical to antimicrobial ones) are thoroughly addressed. Finally, applications and challenges to the widespread use of essential oils are critically discussed.

Quality characteristics of shucked crab meat (Eriocheir sinensis) processed by high pressure during superchilled storage

High-pressure processing (HPP) at 300 MPa for 20 min at 25°C was used for shucking Chinese mitten crab. The shelf-life, quality as well as internal protein changes in HPP-shucked meat were investigated during superchilled storage at -4^o C. Upon 3-week storage, the lightness and whiteness of HPP-shucked crab meat start to decline, while no significant changes were observed in the hardness, gumminess, and chewiness. Sensory and microbial evaluation suggested that HPP-shucked crab meat can be generally preserved in an acceptable manner within 3 weeks, although a negative influence on drip loss was found. The loss of entrapped water in crab meat as revealed by low field nuclear magnetic resonance was responsible for the relatively high thawing drip loss. The severe deterioration of meat quality and sensory occurred at 4-week storage probably as a result of exacerbated myofibrillar protein oxidation, denaturation, and crosslinking. PRACTICAL APPLICATIONS: It has been confirmed that HPP shucking can maintain the fresh-state of the crab meat and save energy compared to the conventional treatment, which could meet consumers' demand for minimally processed seafood products. In this work, the shelf-life of HPP-shucked crab meat stored at -4^o C was evaluated to be 3 weeks and HPP shucking combined with superchilling can be an effective way to preserve the crab meat. These results can provide basic knowledge for the storage and distribution of HPP-shucked crab meat.

Suitability Assessment of PLA Bottles for High-Pressure Processing of Apple Juice

The aim of the present study is to assess the use of polylactic acid (PLA) bottles as an alternative to polyethylene terephthalate (PET) ones for high-pressure processing (HPP) of apple juice. The treatment of PLA bottles at 600 MPa for 3 min did not cause alterations in the packaging shape and content, confirming the suitability of PLA bottles to withstand HPP conditions as well as PET bottles. Quantification of total mesophilic bacterial and fungal load suggested HPP treatment can be effectively applied as an alternative to pasteurization for apple juice packed in PLA bottles since it guarantees microbial stability during at least 28 days of refrigerated storage. The headspace gas level did not change significantly during 28 days of refrigerated storage, irrespective of the bottle material. Color parameters (L*, a*, and b*) of the HPP-treated juice were similar to those of the fresh juice. Irrespective of the packaging type, the total color variation significantly changed during storage, showing an exponential increase in the first 14 days, followed by a steady state until the end of observations. Overall, PLA bottles proved to offer comparable performances to PET both in terms of mechanical resistance and quality maintenance.

Effects of high hydrostatic pressure processing on structure and functional properties of biodegradable film

Effects of high hydrostatic pressure (HHP) processing (200–400 MPa/5 or 10 min) on functional properties of cellulose acetate (CA) films were investigated. As for mechanical properties, HHP caused a reduction in tensile strength (TS), Young's modulus (YM) and an increase in elongation at break (EB). The pressurized films were more luminous, yellowish, reddish and opaque. Less affinity for water was detected for pressurized films through analyses of contact angle and moisture absorption, in addition to reducing the water vapor transmission rate (WVTR). Scanning electron microscopy (SEM) showed the occurrence of delamination for most films, except those treated with 200 MPa/10 min and 300 MPa/10 min. All films showed a predominance of amorphous structure in X-ray diffraction analysis (XRD). That is alignment with the results of differential scanning calorimetry (DSC), which presented values for glass transition temperature (Tg), water adsorption and melting temperature characteristic of materials with low crystallinity. Films treated with HHP had better mechanical resistance during the sealing at 250 °C. In overall the results confirmed the minimal influence of HHP on the functional properties of the CA film and contributed to the scientific and technological knowledge for its potential application in foods processed by HHP.

Multilayer packaging: Advances in preparation techniques and emerging food applications

In recent years, with advantages of versatility, functionality, and convenience, multilayer food packaging has gained significant interest. As a single entity, multilayer packaging combines the benefits of each monolayer in terms of enhanced barrier properties, mechanical integrity, and functional properties. Of late, apart from conventional approaches such as coextrusion and lamination, concepts of nanotechnology have been used in the preparation of composite multilayer films with improved physical, chemical, and functional characteristics. Further, emerging techniques such as ultraviolet and cold plasma treatments have been used in manufacturing films with enhanced performance through surface modifications. This work provides an up-to-date review on advancements in the preparation of multilayer films for food packaging applications. This includes critical considerations in design, risk of interaction between the package and the food, mathematical modeling and simulation, potential for scale-up, and costs involved. The impact of in-package processing is also explained considering cases of nonthermal processing and advanced thermal processing. Importantly, challenges associated with degradability and recycling multilayer packages and associated implications on sustainability have been discussed.

Healthy expectations of high hydrostatic pressure treatment in food processing industry

High hydrostatic pressure processing (HPP) is a non-thermal pasteurization technology which has already been applied in the food industries. Besides maintaining the food safety and quality, HPP also has potential applications in the enhancement of the health benefits of food products. This study examines the current progress of research on the use of HPP in the development of health foods. Through HPP, the nutritional value of food products can be enhanced or retained, including promotes the biosynthesis of γ-aminobutyric acid (GABA) in the food materials, retains immunoglobulin components in dairy products, increases resistant starch content in cereals, and reduces the glycemic index of fruit and vegetable products, which facilitates better control of blood glucose levels and decreases calorie intake. HPP can also be utilized as a hurdle technology in combination with existing processing technologies for the development of low-sodium food products and the maintenance of microbial safety, thereby lowering the risk of triggering cardiovascular disease. Additionally, HPP can be used to enhance the diversity of probiotic food products. Appropriate sporogenous probiotics can be screened and added to various high-pressure processed food products as a certain bacterial count is still retained in the products after HPP. As HPP causes physical damage to the structures of food products, it can also be used as a synergistic extraction technology to enhance the extraction efficiency of functional components, thereby reducing extraction time. By applying HPP in the extraction of functional components from food waste, the production costs of such components can be effectively reduced. This study provides a summary of the mechanisms by which HPP enhances the health benefits of food products and the current progress of relevant research. HPP possesses huge potential in the development of novel health foods and may provide an abundance of benefits to human health in the future.

Molecular Dynamics Simulation on the Diffusion of Flavor, O2 and H2O Molecules in LDPE Film

The diffusion of five flavor organic molecules, including D-limonene, myrcene, ethyl hexanoate, 2-nonanone, and linalool in low density polyethylene (LDPE) film were investigated by combined experimental and molecular dynamics (MD) simulation studies. The diffusion coefficients derived from the prediction model, experimental determination, and MD simulation were compared, and the related microscopic diffusion mechanism was investigated. The effects of the presence of the flavor organic molecules on the diffusion of O₂ and H₂O in polyethylene (PE) were also studied by MD simulation. Results show that: The diffusion of five flavor molecules in LDPE is well followed to Fick’s second law by the immersion experiment; MD simulation indicates the dual mode diffusion mechanism of the flavor molecules is in LDPE; the diffusion coefficients from MD simulation are close to those from the experimental determination, but are slightly larger than those values; the presence of the flavor organic molecules hinders the diffusion of O₂ and H₂O, which can be well explained from the fraction of free volume (FFV) and interaction energy calculation results derived from MD simulation.