Influence of Different Packaging Materials on the Composition of the Headspace of Rennet Cheeses under Different Modified Atmosphere Conditions

The aim of this study was to analyze the influence of different packaging materials on the composition of the headspace (CO2 and O2) of rennet cheeses packed in unit packaging under different modified atmosphere (MAP) conditions during a storage period of 90 days at 2 °C and 8 °C. The packaging materials comprised different combinations of BOPP-biaxially oriented polypropylene; PET-polyester; PE-polyethylene; PP-polypropylene; EVOH-ethylene-vinyl alcohol copolymer; PET-polyethylene terephthalate; and PA-polyamide. As the properties of the packaging material (foil) affect the gas conditions inside the packaging, it is important to study whether the modifications, i.e., properties and thickness, of the foils will result in significant differences in the composition of the headspace of packed cheeses. The CO2 content in the headspace of Gouda cheese packages ranged from 35% to 45%, while for Maasdamer and Sielski Klasyczny cheese, it varied between 55% and 65%. Throughout the storage period, the O2 content in the headspace of cheeses packaged in tested foils (1-5) did not exceed 0.5%. The type of foil used did not influence the modified atmosphere packaging (MAP) conditions.

Influence of sustainable packaging material and packaging conditions on physicochemical, microbiological, and sensorial properties of cheeses

The aim of this study was to evaluate the influence of different packaging materials [standard foil: BOPP (biaxially oriented polypropylene)/PET (polyester)/PE (polyethylene) for upper layer, and APET (polyethylene terephthalate)/PE for bottom layer; foil 1: PP (polypropylene)/PET/PE/EVOH (ethylene-vinyl alcohol copolymer)/PE upper layer, and PP/PE/EVOH/PE bottom layer; foil 2: PP/PET/PE/EVOH/PE upper layer, and PA (polyamide)/EVOH/PE bottom layer; foil 3: PP/PET/PE upper layer, and PA/EVOH/PE bottom layer; foil 4: PP/PET/PE upper layer, and PA/PE bottom layer; foil 5: PP upper layer, and PP/PP bottom layer] on the quality of 3 different ripening rennet cheeses packed under different modified atmosphere (MAP) conditions as reflected in particular physicochemical, microbiological, and sensorial changes. The changes were monitored during a period of 90 d of storage at 2°C or 8°C. For Gouda cheese, CO2 content of the headspace of the packages was in the range 35% to 45%, whereas for Maasdamer and Sielski Klasyczny cheeses it was 55% to 65%. Three-way ANOVA showed that the foil type influenced the moisture content of Gouda cheese stored for 90 d at 2°C and for Sielski Klasyczny cheese at 8°C, whereas the moisture content was not dependent on MAP conditions during storage. Moreover, the foil type had a significant effect on free fatty acid changes for Gouda and Sielski Klasyczny cheeses stored at 2°C for 90 d. Sensory attributes changed significantly over storage time at 2°C for all studied cheeses as affected by foil type, whereas there was no effect of MAP conditions. In general, the cheeses packed in standard foil and foil 4 were characterized by the highest values of mean sensory attributes. Time was the most significant factor influencing most changes in physicochemical and sensory attributes of cheeses stored at 2°C and 8°C. The storage temperature did not affect the moisture of the samples during storage. In general, we found an increase in the pH value during storage regardless of storage temperature. It was possible to decrease the thickness of the packaging material from initial 103 and 250 µm (standard foil; lid and bottom, respectively) to 98 and 100 µm (foil 4) without affecting sensory attributes of the product.

A novel breathable package system to improve the fresh fig (Ficus carica L. 'Dottato') shelf life

BACKGROUND

The postharvest management of fresh figs is a susceptible phase that could impair the quality standards. Given the high perishability, their marketing is limited to around the production areas using open punnets and when marketed non-locally the use of modified-atmosphere packaging enables their quality maintenance up to 7-14 days, depending upon the cultivar, storage temperature, and packaging system. We show the results of the effectiveness of an innovative packaging system endowed with a breathable device (Blow Device®, BD) for fresh fig storage. BD was evaluated in comparison with a sealed (S) and a macro-perforated film-based tray (MF), at 2 and 8 °C.

RESULTS

The lowest rot decay incidence was observed in S and BD (5-20% after 21 days). S significantly mitigated rot and physical-mechanical decay rate compared with BD and MF. However, S led to anoxia, with relevant carbon dioxide (CO₂ ) content (30-40%), tray volume increasing, and the highest titratable acidity values. The exploitation of BD led to 10-15% oxygen (O₂ ) and 5-10% CO₂ , along with storage. After 14 days, the figs packed with BD had a negligible mass loss (0.2%) and excellent marketing quality parameters at both temperatures tested.

CONCLUSION

Exploiting an open or sealed container for extend the fresh fig' storage is not appropriate due to the severe effect of O₂ or CO₂ accumulation, respectively. BD enables the maintenance of high quality standards for up to 21 days at 2 °C, suggesting it could represent a profitable and sustainable solution to prevent decay after picking and reduce food losses along with wider marketability. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Development of a Controlled-Ventilation Box for Modified-Atmosphere Storage of Fresh Produce

Adjusting beneficial gas concentrations in real time in response to changing storage conditions is important for fresh produce, especially throughout the supply chain when temperature abuse occurs frequently. In this study, a controlled-ventilated box for bulk transportation of fresh produce was demonstrated and tested under variable temperatures. The presented system comprised a rigid container with a miniature blower installed in the opening of its wall for facilitating the gas exchange and an additional wall opening with a metal tube protruding into the inner container's space. The in-package atmosphere was formed by the balance between the respiratory activity of the produce and the influx of fresh air through the wall openings, regulated by switching the blower ON or OFF. The mass transfer coefficient for metal tubes of different dimensions was measured under modified atmosphere featuring 15% CO₂ and 5% O₂ at 10 °C. The addition of an air blower increased the mass transfer coefficient by at least 100 times. A further storage trial with cherries was successfully performed at 10 °C and 20 °C. The demonstrated trial featured some significant inputs to increase the knowledge about better storage of fresh produce throughout the supply chain and storage.

The combined impact of calcium lactate with cysteine pretreatment and perforation-mediated modified atmosphere packaging on quality preservation of fresh-cut 'Romaine' lettuce

The effect of perforation-mediated modified atmosphere packaging (PM-MAP) in combination with calcium lactate (1.5% CaL) and cysteine (0.1, 0.5% Cys) immersion pretreatments on the quality preservation of fresh-cut 'Romaine' lettuce was assessed for 12 days, at 5 and 10 °C. The shredded lettuce was packed in low-density polyethylene films (LDPE, 62 µm thickness), including different perforation numbers of 0 (N-MAP), 20 (20-PM-MAP, Diameter = 64 µm), and 40 (40-PM-MAP, Diameter = 64µm) per in square meter. Indices of quality maintenance were investigated. The total microbial counts were below the specified limits for ready-to-eat vegetables (< 6 log CFU/g) considering both pretreated 20-PM-MAP and N-MAP samples on day 12. After 8 days, a significant difference (P < 0.05) was observed in the browning index (BI), the total color difference (ΔE), and the chlorophyll content between N-MAP and 20-PM-MAP samples with better results in 20-PM-MA packages. At 10 °C, the BI in pretreated 20-PM-MAP samples was 32.44% to 58.35% less than N-MAP samples, on the last day of storage. The 20-PM-MAP samples pretreated with 1.5% CaL/0.5% Cys had the highest (P < 0.05) crispness coefficient and water content values. It seems that packaging the pretreated lettuce in 20-PM-MA packages is more effective for maintaining the visual properties (green fresh appearance) of this product, from the 8th to the 12th day of storage. PRACTICAL APPLICATION: The medium to high respiration rate of fresh-cut lettuce causes O2 level drops below its tolerance limit (<1% to 3%) inside the modified atmosphere packaging (MAP). It results in severe browning, off-odors, off-flavor, and growth of anaerobiosis. Perforated-mediated modified atmosphere packaging (PM-MAP) technology can be introduced as an alternative to a nonperforated MAP system (conventional MAP) for fresh-cut lettuce. The application of the PM-MAP system in combination with calcium lactate and cysteine immersion pretreatment (CaL/Cys) may lead to better maintenance of the physicochemical properties of this product.

The microperforated packaging design and evaluation of shelf life of fresh-sliced mushrooms

Fresh mushrooms have a very short shelf life, of 1 – 3 days because of their high respiration rate and lack of cuticles that protect the plant from external factors. In the case of fresh-sliced mushrooms, they will be more susceptible to spoilage reactions due to the increase in respiration rate as a result of a broader surface area. Conventional packaging materials can not meet the requirements for modified atmosphere packaging of fresh-sliced mushrooms. One of the techniques to extend the fresh-cut produce shelf life is the passive modification of modified atmosphere packaging technology. For highly respiring fresh-cut produce such as fresh-sliced mushrooms, the permeability properties of the polymeric materials might not be enough to provide an equilibrium gas concentration in the passive modification of modified atmosphere technology. In this case, the microperforated packaging materials can be used for passive modification of fresh-cut produce. But the microperforation process needs a design for the application of the appropriate number and diameter of microholes to meet the requirements of passive modified atmosphere packaging. For this reason in this research, the design of the microperforation process to be used in passive modified atmosphere packaging was based on the diameter and the number of microholes, and the shelf life of fresh-sliced mushrooms was determined. The samples were stored at 15 °C/80% RH, and pH, color, weight loss, textural, sensorial, and microbial analysis were performed periodically during storage. It was determined that the empirical equation used in this research can be applied to microperforated packaging design for fresh-sliced mushrooms. The shelf life of the fresh-sliced mushrooms packaged with microperforated packaging material was 8 days, while it was less than 7 days (4, 5, or 6 days) when packaged with non-microperforated packaging material. This result shows that the use of microperforated packaging material is effective in extending the shelf life of fresh-sliced mushrooms.

Modified atmosphere packaging of strawberry fruit: Effect of package perforation on oxygen and carbon dioxide / Envasado de fresas en atmósfera modificada: Efecto de la perforación del envase en el contenido de oxígeno y dióxido de carbono

The effect of film perforation on gas content during modified atmosphere packaging of strawberry fruit was studied. Camarosa strawberries were refrigerated at 2 °C, and wrapped with polypropy lene (PP) film with perforations of 1 and 2 mm diameter. Fruits were held at 2 °C during three days, simulating refrigerated transport, and then at 20 °C for four days to simulate retail display tempera tures. Perforation degree affected final gas contents inside the packages, ranging from 5.68-25.96% CO2 and from 4.84-15.69% O2 on day 7. Different gas content profiles were found among packages with similar perforated surface but distinct diameter perforations, which could infer a perforation edge effect on gas exchange. Neither a CO, stratification effect nor a gas exchange site effect were observed for this kind of perforation-mediated modified atmosphere packaging of strawberries.

Preservation of different fig cultivars (Ficus carica L.) under modified atmosphere packaging during cold storage

BACKGROUND

The effect of modified atmosphere packaging (MAP) on the stability of 'Cuello Dama Blanco' (CDB), 'Cuello Dama Negro' (CDN) and 'San Antonio' (SA) figs during post-harvest cold storage was evaluated by using three different films with a diverse number of microperforations (diameter, ø = 100 µm): M10 (16 holes), M30 (five holes) and M50 (three holes). A macroperforated film was used as control (five holes, ø = 9 mm). Gas composition, weight loss, percentage disorder, microbial counts and physico-chemical parameters were monitored during cold storage for 21 days. Furthermore, sensory quality was also evaluated.

RESULTS

MAP has allowed the extension of cold storage and distribution time for the three different cultivars of figs, minimising weight loss and delaying pathological disorders related to endosepsis, smut, and souring. Of the three cultivars, the M50 batch (one hole per 50 mm) showed the best efficiency in terms of physico-chemical quality and delay of post-harvest decay, although the M30 batch was also found to be suitable for delaying the post-harvest decay, especially for the CDB cultivar.

CONCLUSION

MAP is a useful tool to extend the storability with optimal quality properties for CDN and SA during 21 days of cold storage and 14-17 days of cold storage for CDB.

Modeling of Changes in Atmosphere Composition in Fresh-cut Peach Packages due to Temperature Fluctuations

Storage temperature is not always constant in the distribution chain of modified atmosphere fresh food packages. A change in temperature means an alteration in the respiration rate of the product and in the gas transmission rates through the film. Because of their high metabolic activity, minimally processed products are particularly sensitive to temperature variation, and hence this study has been carried out with five cultivars of fresh-cut peaches (Prunus persica). Their respiratory activity has been determined by a closed system at 4, 15, and 25 °C. The peach segments are wrapped in microperforated films whose transmission rate is determined according to the size of the microperforations (between 100 × 130 μm and 215 × 190 μm). To quantify the effect of temperature fluctuations (5 h at 25 °C) on the O2 and CO2 concentrations of the packaging atmosphere of the product, a mathematical model has been applied. Using experimental data, it has been established that the rate of O2 consumption is a potential function of the O2 concentration, while the production of CO2 is linear. Although, all cultivars are of nonmelting fresh with no big differences in respiratory activity; these differences are accentuated with O2 concentrations greater than 10% and raising the temperature. The solution of the model provides knowledge of the behavior of the product during its nonstationary period and equilibrium once reached. The results show in all cases that the CO 2 concentration is more sensitive (increase of 5 units) to a break in the cold chain than that of O2 (reduction of 2 units).