• Korean Journal of Food Science and Technology
• /
• v.30 no.5
• /
• pp.1140-1145
• /
• 1998

Low density polyethylene (LDPE) films incorporated with 1% antimicrobial agents of Rheum palmatum extract, Coptis chinensis extract, and Ag-substituted inorganic zirconium matrix, were applied to modified atmosphere packaging of 200 g fresh strawberries. Plain LDPE film package, PVC wrap and perforative pinhole package of the film impregnated with 1% Rheum palmatum extract were also constructed for comparative purpose. All the packages were stored for 13 days at $5^{\circ}C$ and measured in package atmosphere, microbial count and quality attributes of the strawberry fruits. The antimicrobial LDPE films retarded the growth in total aerobic bacteria, lactic acid bacteria and yeast on the fruits, and resulted in significantly lower decay. The degrees of reduced microbial growth and fruit decay in the antimicrobial film packages were more pronounced, when applied by hermetical sealing to produce the modified atmospheres of low $O_2$ (<4.0%) and $CO_2$ concentrations with $6.3{\sim}9.0%$. The hermetically sealed packages of antimicrobial LDPE films also showed better retention of fruit firmness and did not give any negative effect on the physical and chemical qualities of strawberries.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.17 no.2
• /
• pp.39-42
• /
• 2011

The aim of this study was to develop the appropriate packaging method for minimally processed sliced onions. The films of different gas permeabilities (LDPE $30{\mu}m$, PD900 and PD941) were used for packaging 1300g of onion slices cut into octuplicate pieces. Perforated LDPE package was prepared as control for comparison. The package atmosphere and onion quality were measured through storage at $1^{\circ}C$ for 38 days. PD900 package of the lowest gas permeability was the best in keeping the fresh-cut onions by maintaining MA conditions of 1-3% $O_2$ and 4-11% $CO_2$ concentrations. The benefits were reduced discoloration, decay and soakness.

• Food Science of Animal Resources
• /
• v.42 no.4
• /
• pp.639-654
• /
• 2022

The current study investigated the effects of the most suitable modified atmosphere packaging (MAP) on the physicochemical, microbiological, and sensory properties of fermented dry sausages during 45 days of refrigeration (4℃) storage period. Treatments were vacuum-packed (control), 25% CO₂/75% N₂ (MAP1), 50% CO₂/50% N₂ (MAP2), 70% CO₂/30% N₂ (MAP3), and 100% CO₂ (MAP4). All MAP samples regardless of their CO₂ composition significantly (p<0.05) decreased in pH, a_w, total plate count, and lactic acid bacteria count values as compared to the vacuum-package during storage. The Enterobacteriaceae count in all MAP packaging was significantly (p<0.05) lower than the vacuum-packed samples and counts in MAP3 and MAP4 samples were markedly (p<0.05) lower than all other treatments in prolonged storage of 15 and 45 days. Based on the thiobarbituric acid reactive substance content at day 15 and 30 storage time, treatments are ranked as follows: Vacuum-packed>MAP1>MAP2>MAP3>MAP4. The a^* of MAP4 was higher than all other treatments. In the final storage days, no variation was exhibited (p>0.05) among treatments in lactic acid aroma and sourness, and MAP2 samples had the lowest (p<0.05) overall acceptability. The use of MAPs with an increase in the CO₂ from MAP1 to MAP4 samples can help in better microbial inhibition than vacuum package, and 70% CO₂/30% N₂ (MAP3) and 100% CO₂ (MAP4) were effective to maintain several quality parameters (a_w, pH, microbial inhibition, stability against lipid oxidation, and instrumental color traits) and extend the shelf life of dry fermented sausage.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.17 no.1
• /
• pp.13-17
• /
• 2011

There is a need in food industry to store minimally processed garlic for long time to have it be used just at the time of demand for final product processing. Optimal modified atmosphere packaging is expected to slow down the quality change extending its storage life. In order to find optimal packaging conditions, plastic films of different gas permeability properties (low density polyethylene (LDPE) $30{\mu}m$, polyolefin $50{\mu}m$ (PD 900), polyolefin $20{\mu}m$ (PD 941)) were used for packaging 400 g of minimally processed garlic. Perforated LDPE packages were prepared as control. The packaged products were stored at $1{\pm}1^{\circ}C$ for 52 days. Package treatments were compared in weight loss, decay, surface color, hardness and soluble solid content. While control package had normal atmosphere of air, LDPE, PD 900 and PD 941 packages attained internal concentration of $O_2$ 4.6% / $CO_2$ 12%, $O_2$ 0.9% / $CO_2$ 21% and $O_2$ 0.5% / $CO_2$ 13% after 45 days, respectively. Control packaging had rapid weight loss with high mold decay and great surface color change in 45 days. In PD 900 film packages of lowest gas permeability, the fresh-cut garlic could be stored without mold decay for 52 days. Except control packaging, there were no significant differences in surface color, hardness and soluble solid content among package treatments.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.16 no.2_3
• /
• pp.53-58
• /
• 2010

Internal gas composition of single unit persimmon package was evaluated at $-1^{\circ}C$ as function of package film area and fruit weight in order to find packaging conditions to achieve the optimal modified atmosphere beneficial for keeping the freshness. With large fruit size(${\approx}230\;g$), low permeable films (LLDPE/PP in 35 or $40\;{\mu}m$ thickness and $30\;{\mu}m$ OPP) with an exact fitness to the fruit (surface area of $0.040\;m^2$) resulted in anaerobic atmosphere with occurrence of browning in long term storage. With medium (${\approx}210\;g$) and medium small (${\approx}190g$) sizes, larger surface area of low permeable $35\;{\mu}m$ LLDPE/PP film provided higher $O_2$ and lower $CO_2$ concentrations causing higher occurrence of softening and blackening discoloration. On the other hand, smaller surface area of lower $O_2$ and higher $CO_2$ concentrations had a high risk of browning. Wise combination of fruit size, packaging film and surface area is required for attaining the beneficial modified atmosphere to prevent the physiological injuries.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.19 no.2
• /
• pp.61-65
• /
• 2013

Modified atmosphere (MA) of reduced $O_2$ and elevated $CO_2$ concentrations has been used for keeping the quality of fresh produce and extending the shelf life. As a way to attain the beneficial MA package around the produce, a gas diffusion tube or perforation can be attached onto the container and controlled on real time in its opening/closing responding to $O_2$ and $CO_2$ concentrations measured by gas sensors. The timely-controlled opening of the gas diffusion tube can work in harmony with the produce respiration and help to create the desired MA. By use of the mathematical modeling, the effect of tube dimension on the controlled container atmosphere was figured out in this study. Spinach and king oyster mushroom were used as typical commodities for designing the model container system (0.35 and 0.9 kg in 13 L, respectively) because of their respiration characteristics and the optimal MA condition ($O_2$ 7~10%/$CO_2$ 5~10% for spinach; $O_2$ 2~5%/$CO_2$ 10~15% for mushroom). With a control logic for the gas composition to stay as close as possible to optimum MA window without invading injurious low $O_2$ and/or high $CO_2$ concentrations, the atmosphere of the sensor-controlled container could stay at its lower $O_2$ boundary or upper $CO_2$ limit under certain tube dimensional conditions. There were found to be the ranges of the tube diameter and length allowing the beneficial MA. The desired range of the tube dimension for spinach consisted of combinations of larger diameter and shorter length in the window of 0.3~2 cm diameter and 0.2~10 cm length. Similarly, that for king oyster mushroom was combinations of larger diameter and shorter length in the window of 0.9~2 cm diameter and 0.2~3 cm in length. Clear picture on generally affordable tube dimension range may be formulated by further study on a wide variety of commodity and pack conditions.

• Journal of the Korean Ceramic Society
• /
• v.33 no.8
• /
• pp.863-870
• /
• 1996

Fabricated modified PZT system for pyroelectric IR sensor were analyzed and characterized for dielectric piezoelectric and pyroelectric properties. Particle size and distribution of source powders were controlled by attrition milling process. 0.05PSS+yPT+(0.95-y)PZ+0.4 wt%MnO2 system was fabricated and investigated sintering density crystal structure and micro-structure through sintering conditions sintering temperature and sintering atmosphere. The poled sintered system of y=0.11 showed the lowest dielectric constant. The dielectric constants were increased with increasing y-mole ratio. The pyroelectric properties of modified PZT systems which were assembled to TO-5 package were measured by IR measurement system average out-voltage of 0.05PSS+0.1PT+0.84PZ+ wt%MnO2 was 3V.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.13 no.2
• /
• pp.67-73
• /
• 2007

A respiration rate analysed by enzyme kinetics-based respiration model and gas permeability data of LDPE film were applied to design the optical modified atmosphere (MA) packaging condition of persimmon (Diospyros kaki cv. Fuyu) fruits. The fruit quality rapidly decreases due to physiology disorder such as softening and peel blackening. $O_2$ permeance ($Q_{O2}$ in $ml{\cdot}hr^{-1}{\cdot}atm^{-1}{\cdot}m^{-2}$) and $CO_2$ performance ($Q_{CO2}$ in $ml{\cdot}hr^{-1}{\cdot}atm^{-1}{\cdot}m^{-2}$) of low density polyethylene (LDPE) film samples were measured at $0^{\circ}C$ and described as function of thickness (L in ${\mu}m$) as $Q_{O2}=(2540{\times}1/L)-16$, and $Q_{CO2}=(13742{\times}1/L)-70$, respectively. MA package containing single persimmon fruit of 225g was designed and tested experimentally at $0^{\circ}C$ by using LDPE films. Package atmospheres predicted from the relationship of $O_2$, $CO_2$ and $N_2$ balances on the packages was in good agreement with those obtained experimentally. Physiology disorder occurrence was the lowest at 52 ${\mu}m$ package that attained optimum gas condition ($O_2$ 2.8% and $CO_2$ 5.4%). The computer simulation was found to be effective to help to design the optimum MA packaging condition of individual persimmon fruit.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.19 no.1
• /
• pp.7-10
• /
• 2013

A packaging system integrated in primary and secondary packages to deliver consumers fresh peach in the produce supply chain was designed and its effectiveness on quality preservation was tested. The master packaging system was designed to contain 6 individual polypropylene film (PP, $30{\mu}m$ thickness) packages of 300 g peach fruit inside $35{\mu}m$ thick low density polyethylene (LDPE) bag located in a corrugated paperboard box. As a variable to attain the desired package atmosphere around the fruit during cold storage and subsequent retail display at higher temperature, different numbers (1, 3 and 7) of microperforations in $59{\mu}m$ diameter were tested on the individual PP packages. As control treatment, six fruits were placed without wrapping in a corrugated paperboard box. During the storage at $5^{\circ}C$, the control and individual packages were periodically separated from the box or master package, moved to the simulated retail shelf conditions of $20^{\circ}C$ and then stored for 3 more days with package atmosphere and fruit quality being measured. The package with 7 microperforations was the best in the ability to attain beneficial MA of 6~10% $O_2$ and 11~19% $CO_2$ around the fruit during the chilled storage at $5^{\circ}C$ and simulated retail display at $20^{\circ}C$. Packages with smaller number of microperforations resulted in anaerobic atmosphere at the low temperature storage and/or the subsequent high temperature display. Compared to control, all the treatments with master packaging system gave better retention of fruit firmness with significantly less weight loss.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.29 no.2
• /
• pp.87-94
• /
• 2023

Fresh bakery products are widely consumed worldwide and therefore particular requirements for their quality characteristics have been established. The shelf life of bakery products is mainly subjected to microbial spoilage and staling. This study investigated the optimum conditions of modified atmosphere packaging (MAP) application to extend the shelf life of the bakery products. The gas conditions of the headspace in 'Baumkuchen' cake were 0, 30, 70, and 100% CO₂ concentrations and stored at 30℃ for 5 days. The bakery samples were evaluated weight loss, hardness, color change, pH and total aerobic bacteria, yeast and molds count throughout the storage period. Values of the weight loss and hardness were increased over the storage period, meanwhile pH was significantly decreased. However, no significant color changes were observed during storage. It was also found no significant difference between the different gas treatments. Total aerobic bacteria count of the stored samples after day 5 was increased by 6.94 log CFU/g in the air filled package, compared to 6.20 log CFU/g in the 100% CO₂ filled package and 6.02 log CFU/g in the 70% CO₂ filled package. Yeast and molds count were 3.65 log CFU/g in air filled package, 2.66 log CFU/g in 100% CO₂ filled package, 2.64 log CFU/g in 70% CO₂ filled package, 2.86 log CFU/g in 30% CO₂ filled package and 3.31 log CFU/g in 100% N₂ filled package on day 2. In conclusion, it was shown that 70% and 100% CO₂ treatments in the package were effective to reduce microbial growth.