Perforation-mediated Modified Atmosphere Packaging Research Articles

Bioactive Compounds of Broccoli Florets as Affected by Packing Micro-Perforations and Storage Temperature

Fresh-cut broccoli is a highly demanded product due to its convenience and high content of bioactive compounds. Unfortunately, this product shows rapid senescence and anoxia generation problems, especially when storage temperature varies. Therefore, perforation-mediated modified atmosphere packaging (PM-MAP) of broccoli florets, in different temperature scenarios, was studied. Polypropylene films with different levels of laser perforation were evaluated. After packaging, florets were stored at two temperatures: 2 °C, and 2 °C + 7 °C (during 2 d before sampling). PM-MAP slightly modified the internal composition of O2 (14–20 kPa) and CO2 (0.9–5 kPa) and allowed us to preserve the external quality and bioactive compounds of broccoli florets throughout 21 d, even at 7 °C. The generation of anoxia was avoided at both temperatures. PM-MAP kept broccoli mass loss below 0.5% and preserved its sensory quality. The perforation level affected evolution of firmness and glucosinolate content, especially with increasing temperature. Broccolis packaged in the film with fewer perforations showed higher firmness (0.73 ± 0.09 N/mm) and total glucosinolate content (10 ± 0.3 mg/g) compared to broccolis packaged in films with higher perforations (0.59 ± 0.05 N/mm and 8.60 ± 0.2 mg/g). Therefore, the perforation level should be taken into account in the design of packaging for fresh-cut products.

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, 62µm thickness), including different perforation numbers of 0 (N-MAP), 20 (20-PM-MAP, Diameter = 64µm), 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.

PENGEMASAN BUAH DAN SAYUR DENGAN ATMOSFIR TERMODIFIKASI

Being living organs, fresh harvested fruits and vegetables remain metabolically active and undergo ripening and senescence processes. They needs oxygen to stay alive, which is vital for energy production through respiration process. Modified Atmosphere Packaging (MAP) technology utilises in-packaging equilibrium atmosphere, in which the relatively low oxygen and high carbondioxide concentration is achieved naturally inside the package as respiration occurs, which later on leads to a lower respiration rate. Low oxygen concentration could also be achieved by replacing some oxygen with nitrogen and/or application of oxygen scavenger inside in package, thus the respiration rate is reduced and the aging process is retarded. The use of packaging films of correct intermediary permiability to meet a desirable equilibrium modified atmosphere become a key to the succes of MAP. A new technique, so called Perforation-Mediated Modified Atmosphere Packaging (PM-MAP), by having microperforation in the plastic films is applied to correct the exchange of air during storage. Therefore Modified Atmosphere Packaging (MAP) technology offers advantages which leads to extension of the shelf life of fresh produces. Fresh and fresh-cut food industry utilise this advantages to meet the growing demand of convinient and fresh quality fruits and vegetables, in order to maintain freshness quality attributes and to extend the shelf life.

Effect of perforation-mediated modified atmosphere packaging on the quality and bioactive compounds of soft kale (Brassica oleracea L. convar. acephala (DC) Alef. var. sabellica L.) during storage

Abstract Perforation-mediated modified atmosphere packaging of soft kale (Brassica oleracea L. convar. acephala (DC) Alef. var. sabellica L.) was investigated to maintain freshness at 10 °C for 12 d. Kale was sealed in micro-perforated pouches with different oxygen transmission rates (OTRs: mL m–2 d–1 atm–1) at 1.66 × 106, 3.0 × 103 or 64. Headspace atmospheres (O2/CO2) of pouches at OTR 1.66 × 106, 3.0 × 103 and 64 were 21 %/0 % (normoxia), 1.9∼7.4 %/8.5∼9.6 % (modified atmosphere) and 0 %/> 20 % (hypoxia), respectively. Hue angles (degree of green color) of leaves in the OTR 3.0 × 103 and 64 pouches were significantly higher than that in the OTR 1.66 × 106 pouch. However, carotenoid and ascorbic acid concentrations in the leaf in the OTR 3.0 × 103 pouch was significantly higher than that in the OTR 64 pouch. The modified atmosphere created in the OTR 3.0 × 103 pouch was suitable for maintaining external (green color) and internal (bioactive compounds) qualities of soft kale.

Effect of perforation-mediated modified atmosphere packaging system on the quality of rucola

Effect of perforation-mediated modified atmosphere packaging system on the quality of rucola

Phytochemical Properties and Antioxidant Activities of Minimally Processed “Acco” Pomegranate Arils as Affected by Perforation-Mediated Modified Atmosphere Packaging

The effects of perforation-mediated modified atmosphere packaging (PM-MAP) on the phytochemicals and antioxidant properties of freshly processed pomegranate arils (cv. Acco) stored at 5C for 15 days were investigated. Perforations 0, 3, 6 and 9 (P-0, P-3, P-6 and P-9, respectively) were made on the polymeric film (POLYLID 107 polyethylene) and non-perforated (P-0) and clamshell trays were control. Total anthocyanins content increased slightly across all treatments and arils packed in P-6 had the highest content of 49.2 ± 0.71 mg C3gE/100 mL. Ascorbic acid content decreased significantly across all treatments (P < 0.05) compared to the initial value (15.3 ± 0.13 mg AA/100 mL) prior to storage. A threefold increase in antioxidant capacity was observed at the end of storage when tested against ferric ion reducing antioxidant power (FRAP) initial value of 43.52 ± 0.73 µM TE/mL. Practical Applications The role of antioxidant properties and phytochemical in fruit in reducing the risk of non-communicable diseases is well established in the literature. Conventional modified atmosphere packaging systems could reduce produce quality attributes due to sub-optimal in-package gas composition. There is a growing interest in package optimization to maintain the sensory and nutritional quality of fresh or fresh-cut fruits. This study had demonstrated that the application of perforation-mediated modified atmosphere packaging retains the bioactive components of fresh pomegranate arils.

Quality of minimally processed carrots in perforation-mediated modified-atmosphere packaging (PM-MAP)

Studies were carried out to investigate the effect of PM-MAP on minimally processed carrots with different number of perforations (0, 4, 12 and control) on flexible package, stored at 2 °C temperature. The effect of PM-MAP on headspace oxygen and carbon dioxide concentration, weight loss, surface color, firmness, pH, total soluble solid, β-carotene and microbial load were evaluated. It was observed that equilibrium modified atmospheric condition of 5–7 % oxygen and 7.8 % carbon dioxide was achieved in 4 perforation pack. Whiteness index (WI) increased in all the samples from the initial value of 22.75 to a range of 30–35 within 8 days of storage. After that, it remained almost constant for all samples except for 0 perforation packs where a decreasing trend was observed. Chroma value (CV) of samples also followed similar trends like WI and reduced from initial value of 63.08 to a range of 50–55 within 8 days of storage and remained in a constant range during further storage. Firmness of carrot slices decreased to 22–24 N and 25–28 N for 4 and 12 perforation pack respectively from initial value of 30 N after 40 days of storage. Lower oxygen availability in 4 perforation pack was main reason behind lower microbial count (5.2 log10 cfu/g) after 30 days of storage. Reduction of 5.52 % and 10.10 % in β-carotene content was observed in 4 and 12 perforation pack samples. Thus for PM-MAP, 150 g of carrot samples in 4 perforation packs proved to be better than other conditions.

Perforation-mediated modified atmosphere packaging of fresh and minimally processed produce—A review

The overwhelming global demand by consumers for convenience and fresh quality fruit and vegetables, heightens the need for appropriate postharvest technologies. In order to maintain freshness quality attributes, extend the shelf life of fresh/minimally processed produce and reduce postharvest losses. Perforation-mediated modified atmosphere packaging (PM-MAP) offers the benefit of avoiding in-package anaerobiosis, extending the shelf life and maintaining quality fresh or minimally processed produce. This article presents an overview on the role of postharvest hurdle technologies in food packaging, critical evaluation of MAP and PM-MAP dependent parameters and the role of mathematical models. Furthermore, the successful application of PM-MAP on fresh and minimally processed produce was highlighted and future research prospects and challenges were identified.

Effect of perforation-mediated modified atmosphere packaging and storage duration on physicochemical properties and microbial quality of fresh minimally processed ‘Acco’ pomegranate arils

This study investigated the effects of number of perforations (P-0, -3, -6 and -9 per 160.1 cm2) and storage duration on the physicochemical quality attributes and microbiological quality of fresh minimally processed pomegranate (Punica granatum L., cv. Acco) arils stored at 5 °C for 15 days. Arils were analysed for physicochemical quality attributes on day 0, 3, 6, 9, 12 and 15. Microbial analyses for aerobic mesophilic bacteria, yeast and moulds were made on 0, 6, 10 and 14 day, and the presence of Escherichia coli was tested before and at the end of storage. Headspace gas composition was significantly influenced by number of perforation. Highest CO2 accumulation was observed in non-perforated MAP, while O2 concentration increased with increase in number of perforations in PM-MAP. Highest decrease in total soluble solids (TSS) from 15.4 to 13.1°Brix was observed in P-9 PM-MAP arils. Highest counts of aerobic mesophilic bacteria (5.5 log CFU g−1) and yeast and moulds (5.3 log CFU g−1) were observed in P-0 and P-9 PM-MAP. No E. coli were detected before and at the end of storage. Overall, P-3 and P-6 PM-MAPs better maintained quality attributes of pomegranate arils than P-0 and P-9.

Applicability of Simplified Simulation Models for Perforation-Mediated Modified Atmosphere Packaging of Fresh Produce

The comprehensive mass balances of differential equations involving gas diffusion and hydraulic convection through package perforation, gas permeation through polymeric film, and produce respiration have commonly been used to predict the atmosphere of perforated fresh produce packages. However, the predictions often suffer from instability, and to circumvent this problem, a simplified diffusion model that omits the convective gas transfer and empirical models based on experimental mass transfer data have been developed and investigated previously by several researchers. This study investigated the potential and limitations of the simplified diffusion model and two empirical models for predicting the atmosphere in perforated produce packages. The simplified diffusion model satisfactorily estimated the atmosphere inside the perforated packages of fresh produce under the aerobic conditions examined. Published empirical models of the mass transfer coefficients of the perforation seem to be valid only for the measured conditions and thus should be used carefully for that specific purpose.

Mass transport analysis in perforation-mediated modified atmosphere packaging of strawberries

A space-and-time dependent mathematical model was developed to predict O2, CO2, N2 and H2O concentration in perforation-mediated polymeric packages during cold-storage of strawberries. The numerical solution of the corresponding mathematical model was obtained by applying the finite element method (FEM). The problem was solved in a domain corresponding to the headspace of a package augmented by the total void spaces of the contained bulk produce and for realistic boundary conditions. Transport of O2, CO2, N2 and H2O was modelled based on Maxwell–Stefan equations for gas transport through packaging’s headspace and on Fick’s law for diffusion through the micro-perforated packaging. The model predictions were tested against published experimental data of O2 and CO2 concentrations in modified atmosphere packaging storage of strawberries and the agreement is satisfactory. As for reaching the recommended in the literature gases concentrations for strawberry storage, the model predictions revealed that the tested micro-perforated polypropylene packaging combined with the adopted storage conditions are marginally adequate. To this end, the theoretical findings are suggestive of improvements, in terms of material properties, especially with regard to the permeability of the polymeric packaging film.

Modelling the gas exchange rate in perforation-mediated modified atmosphere packaging: Effect of the external air movement and tube dimensions

Perforation-mediated modified atmosphere packages control the gas exchange rate and thus the internal atmosphere composition by judicious choice of dimensions of small tubes in perforations in an otherwise hermetic container. The aims of this work were (i) to study the effect of external turbulence on the gas exchange rate through small perforations, (ii) to develop a mathematical model to predict the effect of tube dimensions and hydrodynamic conditions on gas exchange coefficients, and (iii) validate the model developed during the storage of shredded carrots. Different hydrodynamic conditions in the controlled temperature room due to the storage temperature settings (5, 10 and 15 °C) and PVC tubes dimensions (diameter from 1.5 to 4.5 mm length from 2.0 to 6.0 mm) were tested. Results showed that, as expected, hydrodynamic conditions (induced turbulence) and tube diameter had a significantly positive effect on the mass transfer values, whereas tube length had a negative effect. The permeability ratio between CO 2 and O 2 was 0.83 ± 0.01 and did not show any pattern with the factors tested. The gas exchange coefficients increased with decreasing temperature, as the establishment of lower temperatures implied a frequent air movement. A mathematical model to estimate changes of gas composition over time as a function of tube dimensions and hydrodynamic conditions was developed and found to have good predictive abilities. The model was validated during the storage of shredded carrots at 5 °C in PM-MAP, showing a good agreement between the experimental and predicted gas exchange of O 2 and CO 2. The results obtained in this work showed that hydrodynamic conditions of the cold storage room affected the gas exchange rate in PM-MAP.

Modelling the effect of gas composition on the gas exchange rate in Perforation-Mediated Modified Atmosphere Packaging

Modified Atmosphere Packaging (MAP) relies on modification of the atmosphere inside a package, achieved by the natural interplay between the respiration of the product and the transfer of gases through the package. Polymeric films are the most usual packaging material but because of the increase in the consumption of fresh-cut products with a higher respiration rate and higher tolerance to CO 2, alternative materials are being investigated. The perforation-mediated package is one of those alternatives, where the regulation of the gas exchange is achieved by single or multiple tubes that perforate an otherwise impermeable packaging material. From an engineering point of view, the transport of gases through perforations is a complex phenomenon that involves diffusion gradients together with co-current transport of multiple species, with oxygen entering the package and carbon dioxide leaving it. The influence of one species transport in the other has not been studied so far. The objective of this work was to analyse the effect of initial concentration of CO 2 on the effective mass transfer coefficients of O 2 ( K O 2 ) and CO 2 ( K CO 2 ) in perforation-mediated MAP. K O 2 ranged from (6.99 ± 0.05) × 10 −8 (m 3 s −1) to (28.50 ± 0.01) × 10 −8 (m 3 s −1) and for K CO 2 from (6.45 ± 0.04) × 10 −8 (m 3 s −1) to (28.32 ± 0.01) × 10 −8 (m 3 s −1). On average K O 2 decreased by approximately 15% with an increase of CO 2 initial concentration from 25% to 100%. K CO 2 was insensitive to the composition of the gas mix. The permeability ratio ( β) varied from 0.73 ± 0.01 to 1.34 ± 0.01. A mathematical model considering the co-current effect of CO 2 flux on the gas exchange rate for O 2 was developed. These results suggest that there is a significant drag effect in the gas exchange process that should be taken into consideration when designing perforation-mediated MAP.

Perforation-mediated modified atmosphere packaging. Part II. Implementation and numerical solution of a mathematical model

The present article describes the numerical implementation of a space-and-time dependent mathematical model of perforation-mediated modified atmosphere packaging for respiring commodities as Part II of a study in which the mathematical model is described in Part I. The model includes species transport of CO 2, H 2O, N 2, and O 2 through the Maxwell–Stefan equations, velocity and pressure through Darcy's law and the Navier–Stokes equations, and temperature of the gas mixture and the commodity through the energy equation. Numerical solutions of the coupled system of equations were obtained using the finite-element method. To illustrate the capabilities of the general approach, simulations of a package of strawberries have been presented, for which experimental results are available in the literature. Comparison of the measurements and the model predictions were fair, considering the uncertainty of the available information. The sensitivities of the solution to the respiration rate model, respiration rates, porosity, package aspect ratio, relative humidity, transpiration coefficients, storage temperature, CO 2 solubility and volume of ambient storage area considered were examined. The steady-state concentrations of O 2 and CO 2 in the package were found to be very sensitive to the value of respiration rate, but much less so to changes of other input parameters within the ranges considered. The steady-state commodity temperature depended on the aspect ratio of the package. Including the CO 2 solubility in the commodity did not affect the steady-state gas concentrations, but it increased the time required for the CO 2 concentration to reach equilibrium in the package. It was shown that neglecting the ambient space beyond the perforation overpredicted the steady-state O 2 concentration. Approximately 80% of the resistance to diffusion was found to occur within the perforation, with the remainder equally divided between the spaces beyond each end of the perforation.

Perforation-mediated modified atmosphere packaging: Part I. Development of a mathematical model

A space-and-time dependent mathematical model describing perforation-mediated modified atmosphere packages was developed for respiring commodities. The model is based primarily on fundamental laws, with empirical relations used only when no other approach can be devised or when there is a significant advantage from using an empirical approach. The computational domain is divided into four subdomains: a part of the ambient storage environment; the perforation, allowing gas exchange between the package and the ambient; the commodity layer, inside the package; and the headspace above the commodity, but also contained in the package. The package walls are rigid and impermeable to gases but heat conducting. The commodity is treated as a homogenous porous medium with distributed sinks for oxygen consumption and distributed sources for carbon dioxide production due to commodity respiration. The commodity model also accounts for water vapour production due to transpiration and removal caused by possible condensation. The effects of commodity temperature and headspace gas composition on oxygen consumption and carbon dioxide production are accounted through a respiration model. The model permits the determination of the gas mixture velocity as the solution of Darcy's law in the commodity layer and the Navier–Stokes equations in the headspace, perforation, and surrounding ambient storage area. Transport of oxygen, carbon dioxide, water vapour and nitrogen is modelled based on Maxwell–Stefan equations coupled with the Navier–Stokes equations and Darcy's law. Solubility of carbon dioxide within the commodity has been included in the model. Commodity temperature and gas mixture temperature are modelled as solutions of the energy equation in the appropriate subdomains, coupled through transpiration, condensation, and convective heat transfer at the commodity surface.

Analysis of water vapour transmission rate of perforation-mediated modified atmosphere packaging (PM-MAP)

Perforation-mediated modified atmosphere packaging relies on the use of perforations (tubes) of different dimensions to control O 2 and CO 2 exchange in order to create the desired atmosphere for preservation of fresh fruits and vegetables. No work has been done so far to measure the water vapour transmission rate (WVTR) of this new system. The present study analyses WVTR in different perforation dimensions (diameter: 9, 13 and 17 mm; length: 10, 20 and 30 mm) and storage temperatures (4, 10 and 16 °C). Diameter was the variable with the greatest influence on WVTR, followed by tube length and temperature. The WVTR of perforation-mediated packages increased with increasing temperature and tube diameter while it decreased with increasing tube length. A mathematical model to describe the changes in WVTR as a function of perforation diameter, length, porosity and storage temperature was developed and validated successfully at 7 °C. An experiment with mushrooms showed that the perforation-mediated modified atmosphere packaging could be used for fresh produce provided that the condensation is minimised by using a moisture absorber.

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.

Modelling O 2 and CO 2 exchange for development of perforation-mediated modified atmosphere packaging

Perforation-mediated modified atmosphere packaging relies on the use of macro perforations or tubes to control the O 2 and CO 2 exchange and create the desired atmosphere inside an otherwise gas-tight package. In this work, the O 2 and CO 2 exchange through a single tube was studied. Different temperatures (5–20°C) and tube dimensions (length from 9 to 17 mm and diameter from 6 to 30 mm) were tested. O 2 and CO 2 mass transfer coefficients were determined according to a lumped mass transfer capacitance model that yielded a good description of the gas transfer. Temperature in the range tested did not show a significant effect on the mass transfer coefficients. A multiplicative non-linear equation was found to yield a good prediction of the dependence of the O 2 mass transfer coefficient on tube diameter and length. The ratio between the CO 2 and O 2 mass transfer coefficients, an important parameter in the design of MAP, was 0.81 and none of the factors tested influenced its value.