Solubility and absorption rate of carbon dioxide into non-respiring foods

Extending the Shelf Life of Atlantic Salmon (Salmo salar) with Sub-Chilled Storage and Modified Atmosphere Packaging in Recyclable Mono-Material Trays

This study investigated the effect of sub-chilling whole gutted salmon and sub-chilled storage at -1 °C in modified-atmosphere packaging in two recyclable mono-material trays (CPET, HDPE). Quality parameters were measured, including water-holding properties, salt content, color, texture, lipid oxidation, and sensory and microbiological shelf life. The oxygen transmission rate was measured for the packages. Compared to traditional fish storage on ice, sub-chilling gave a 0.4% weight gain, better water-holding capacity, and higher salt content. The sub-chilled fish gave a significantly better sensory quality and microbiological shelf life of up to 49 days. Photobacterium was the dominating bacteria during storage. Salmon packaged in CPET trays had a higher drip loss than HDPE trays, but a lower rate of lipid oxidation (1-penten-3-ol). Our results showed the feasibility of significantly extending shelf life with sub-chilling, removing the need for ice. Moreover, using recyclable trays for packaging contributes to a circular economy without compromising food quality.

The Potential of Soluble Gas Stabilization (SGS) Technology in a Simulated Post-Frying Cooling Step of Commercial Fish Cakes

Soluble gas stabilization (SGS) technology is a novel way to increase the effectiveness of modified atmosphere (MA) packaging. However, SGS can be time-consuming and difficult to include in an existing process. This can be overcome by including CO₂ in an existing processing step, such as the product's cooling step. A full factorial design was set up with SGS times (0.5, 1.0, and 2.0 h) and temperatures of fish cakes (chilled (0 °C) or during chilling (starting at 85 °C)) as factors. MA-packaged fish cakes were included as a control. The response was headspace gas composition at equilibrium. Headspace gas composition at equilibrium showed significantly (p < 0.05) less dissolved CO₂ in hot fish cakes after 0.5 h than in cold cakes. Still, no significant differences were found between hot and cold at 1.0 and 2.0 h. Also, all SGS samples, regardless of time and temperature, had a higher content of CO₂ compared to modified atmosphere packaging (MAP).

Application of soluble gas stabilization technology on ready-to-eat pre-rigor filleted Atlantic salmon (Salmo salar L.)

Abstract

The demand for high‐quality, convenient, and sustainable salmon products represents a potential for value‐added product development and novel packaging solutions. Soluble gas stabilization (SGS) technology, which applies dissolved CO₂ in the product before packaging, represents a novel approach to retain product quality and prevent microbiological deterioration during cold storage of pre‐rigor filleted salmon loins.

The present study aimed to examine the solubility of CO₂ in salmon loins as affected by rigor status. In addition, the effect of predissolved CO₂ on the overall quality of pre‐rigor vacuum‐packed Atlantic salmon (Salmo salar L.) was investigated during storage at 4°C. The CO₂ pretreatment was conducted, exposing loins to 100% CO₂ for 18 h at 4°C (the control group was kept in air at 4°C) before repackaging and storage for 15 days.

Dissolved CO₂ in the muscle (equilibrium achieved four days post packaging) was slightly higher in pre‐rigor than post‐rigor salmon loins (p_equilibrium = 0.006). Moreover, the overall spoilage (Hvalue) and microbiological stability of salmon fillets stored in SGS‐vacuum were significantly improved compared to vacuum‐packed loins (p < 0.05).

The results demonstrate that SGS technology can maintain the overall quality of pre‐rigor vacuum‐packed salmon loins without introducing the high gas‐to‐product volume ratio recognized by modified atmosphere packaging. Thus, the application of SGS technology on pre‐rigor loins can lead to higher economic gain and environmental benefits due to the reduced amount of required packaging material and reduced food waste.

Practical Application

CO₂ can be dissolved in pre‐rigor salmon loins before vacuum packaging to increase product shelf life during cold storage.

Effect of edible coating and modified atmosphere packaging on the microbiological and physicochemical stability of retail maki sushi

The effect of pH, packaging atmosphere (100% air, 40%, or 70% CO₂ balanced with N₂ ), and an edible chitosan coating was tested on the retail maki Sushi's microbiological and physiochemical stability. In two experiments, maki sushi was studied using sushi rice with an initial pH of 4.2 ± 0.05 and 4.8 ± 0.05. In the first experiment (lower pH), no apparent effect of neither modified atmosphere packaging (MAP) nor coating on bacterial growth was observed. However, raising the pH showed an apparent effect of low-CO₂ MAP and chitosan coating (p < 0.05). Both MAP and coating partly affected the maki sushi cross-section's visual perception, but no significant adverse effects were observed. An important observation was the improved stability of the pink salmon color in chitosan-coated maki sushi stored in low-CO₂ MAP compared to other groups. It is concluded that storage of Maki sushi at 4°C gives acceptable microbial stability and appropriate quality. However, an edible chitosan coating, especially in combination with low-CO₂ MAP, increases the microbiological stability and preserves the colorimetric properties of maki sushi stored at 8°C. Notably, this combination could work as a safety measure against temperature abuse in the food cold chain. PRACTICAL APPLICATION: Using an edible coating with active packaging can improve retail maki sushi's temperature tolerance and preserve its colorimetric properties. It is a fast and cost-effective technology with a substantial industrial potential easy to implement.

Mild processing of seafood-A review

Recent years have shown a tremendous increase in consumer demands for healthy, natural, high-quality convenience foods, especially within the fish and seafood sector. Traditional processing technologies such as drying or extensive heating can cause deterioration of nutrients and sensory quality uncompilable with these demands. This has led to development of many novel processing technologies, which include several mild technologies. The present review highlights the potential of mild thermal, and nonthermal physical, and chemical technologies, either used alone or in combination, to obtain safe seafood products with good shelf life and preference among consumers. Moreover, applications and limitations are discussed to provide a clear view of the potential for future development and applications. Some of the reviewed technologies, or combinations thereof, have shown great potential for non-seafood products, yet data are missing for fish and seafood in general. The present paper visualizes these knowledge gaps and the potential for new technology developments in the seafood sector. Among identified gaps, the combination of mild heating (e.g., sous vide or microwave) with more novel technologies such as pulsed electric field, pulsed light, soluble gas stabilization, cold plasma, or Ohmic heat must be highlighted. However, before industrial applications are available, more research is needed.

The pathogenic and spoilage bacteria associated with red meat and application of different approaches of high CO2 packaging to extend product shelf-life

With the fast-global development of packaging techniques, the potential antimicrobial effect of CO₂, as a safe, cheap and readily available gas, makes it the integral component for packaging of meat products. The associated spoilage and/or pathogenic bacteria on raw meat may respond in different ways to elevated CO₂ concentrations. The growth of some aerobic Gram-negative bacteria such as Pseudomonas spp. is significantly inhibited but some LAB bacteria may be allowed to grow faster and dominate the product. The antimicrobial efficacy of enriched CO₂ packaging is attributed to the rate of CO₂ solubility in the product which is itself affected by the level of headspace CO₂, product pH, temperature and the ratio of headspace gas to product (G:P). This review, first, explores the varied range of beef and sheep meat spoilage and pathogenic bacteria and the intrinsic and extrinsic parameters that may influence the pattern of microbial growth and meat spoilage rate during storage. Then, the antimicrobial mechanism of elevated CO₂ packaging will be discussed and the different approaches of achieving enriched CO₂ packaging i.e. the traditional technique of flushing a desired gas mixture and/or using the new commercially developed CO₂ emitters will then be compared in terms of their strengths, limitations and technical mode of action.

Effects of Soluble Gas Stabilisation, Modified Atmosphere, Gas to Product Volume Ratio and Storage on the Microbiological and Sensory Characteristics of Ready-to-Eat Shrimp (Pandalus borealis)

The effects of storage time, modified atmospheres (30% or 60% CO2), soluble gas stabilisation and gas to product volume ( g/ p) ratio were investigated on the microbiological and sensory characteristics of cooked, peeled and brined ready-to-eat (RTE) deep-water shrimps ( Pandalus borealis). Soluble gas stabilisation (SGS) treatment prior to packaging (2h) increased the CO2 content in the packaged shrimp and counteracted package collapse, even at low g/ p ratios (0.66). SGS treatment reduced significantly (P 0.01) the aerobic plate count and psychrotrophic count. The increase of CO2 levels during modified atmosphere (MA) packaging and the application of SGS significantly enhanced (P 0.01) the sensory quality of the shrimps. The exudates in the packages (%) were significantly reduced (P 0.01) when applying SGS treatment. Therefore, SGS treatment in combination with MA packaging can be used successfully on RTE shrimps to reduce the package volume and to improve the microbiological and sensory characteristics.

Modified Atmosphere Systems and Shelf Life Extension of Fish and Fishery Products

This review aims at summarizing the findings of studies published over the past 15 years on the application of modified atmosphere (MA) systems for shelf life extension of fish and fishery products. This review highlights the importance of CO₂ in the preservation of seafood products, and underscores the benefits of combining MA technology with product storage in the superchilled temperature range. It is generally accepted that MA technology cannot improve product quality and should not be utilized as a substitute for good sanitation and strict temperature control. Benefits derived from application of MA, however, can significantly impact preservation of product quality and it subsequent shelf-life. For this reason, this review is the first of its kind to propose detailed handling and quality guidelines for fresh fish to realize the maximum benefit of MA technology.

Quality changes of cuttlefish stored under various atmosphere modifications and vacuum packaging

BACKGROUND

Seafood preservation and its shelf life prolongation are two of the main issues in the seafood industry. As a result, and in view of market globalization, research has been triggered in this direction by applying several techniques such as modified atmosphere packaging (MAP), vacuum packaging (VP) and active packaging (AP). However, seafood such as octopus, cuttlefish and others have not been thoroughly investigated up to now. The aim of this research was to determine the optimal conditions of modified atmosphere under which cuttlefish storage time and consequently shelf life time could be prolonged without endangering consumer safety.

RESULTS

It was found that cuttlefish shelf life reached 2, 2, 4, 8 and 8 days for control, VP, MAP 1, MAP 2 and MAP 3 (20% CO2 -80% N2 , 50% CO2 -50% N2 and 70% CO2 -30% N2 for MAP 1, 2 and 3, respectively) samples, respectively, judging by their sensorial attributes. Elevated CO2 levels had a strong microbiostatic effect, whereas storage under vacuum did not offer significant advantages. All physicochemical attributes of MAP-treated samples were better preserved compared to control.

CONCLUSION

Application of high CO2 atmospheres such as MAP 2 and MAP 3 proved to be an effective strategy toward preserving the characteristics and prolonging the shelf life of fresh cuttlefish and thereby improving its potential in the market. © 2015 Society of Chemical Industry.

Effect of food matrix and pH on the volatilization of bases (TVB) in packed north Atlantic gray shrimp (Crangon crangon): volatile bases in MAP fishery products

The total volatile basic nitrogen fraction (TVB-N) is often used as a quality parameter in the fish industry to assess spoilage. This parameter often leads to discussions between producers and retailers when it comes to defining clear limits of acceptability for modified atmosphere (MA) packed fish and fishery products. Suggested product limits (mg N/100 g fish) do not always correlate with the presence of off-odors. Gray shrimp are an economic valuable, very perishable niche product, where the TVB-N fraction plays an important role considering its shelf life. This research focuses on the effect of a shrimp matrix and its pH on the volatilization of these formed bases, revealing the relationship between concentrations in the fishery product and the concentrations of these bases present in the headspace of the packed product. Especially, the pH of the product, which is lowered when fishery products are packed under a carbon dioxide enriched atmosphere, appeared to have an immense effect on the volatilization of these bases. The effect of the fish matrix itself is established by means of calculated equilibration constants (dimensionless) being 2.13×10(-4)±0.38×10(-4) for trimethylamine, 6.34×10(-5)±1.71×10(-5) for dimethylamine, and 2.58×10(-5)±0.49×10(-5) for ammonia. Comparison of these constants with the equilibration constants of an aqueous solution indicated the retention of these bases in the product. This article provides not only the important insights for the interpretation of TVB-N values in modified atmosphere packaged gray shrimp but also the methodology to extend these findings to other fish and fishery products.

Enhancement of Modified Atmosphere Packaged Farmed Atlantic Halibut (Hippoglossus Hippoglossus) Fillet Quality by Soluble Gas Stabilization

The suitability of soluble gas stabilization (SGS) to dissolve CO2 into Atlantic halibut ( Hippoglossus hippoglossus) fillets prior to modified atmosphere packaging (MAP) were investigated. Two levels of CO2 partial pressures (200 and 400 kPa) and two levels of time (1 and 2h) with SGS treatment was used in a factorial design, and compared to conventional MAP. Headspace gas volume (mL), headspace gas composition (%), drip loss (%), pH, microbiological characteristics, off-odor and color were assessed on the packaged fillets. Increased partial pressure and increased SGS treatment time before MAP significantly ( p<0.001) increased the CO2 content in the packaged fillets and counteracted package collapse. No interaction between the time and partial pressure was found. SGS treatment significantly ( p = 0.038) reduced aerobic plate count (APC) and psychrotrophic count (PC). APC and PC increased significantly the tree first sampling days during storage (7, 15, and 21) and stabilized from day 21 to day 28. H2S producing bacteria and Brochothrix thermosphacta was not affected by the SGS treatment. H2S producing bacteria decreased significantly from day 7 to day 15. SGS treatment decreased the drip loss significantly ( p = 0.006). Color and pH were not affected by the SGS treatment. No difference in the off odor was found between the treatments. Based on off odor analysis, the shelf life of the halibut fillet in this trial exceeded 28 days.