Polypropylene Film Packaging Research Articles

‘맛경채’의 포장방법과 저장온도에 따른 선도 비교

‘Mats-kyeong-chae (Brassica lee ssp. namai cv. Tongssamchoo)’, a new type of sweet Korean cabbage for fresh wrapping and soup cooking, was released by the Korea National College of Agriculture and Fisheries. The shelflife and quality changes of this new cultivar was evaluated by packaging with PP (polypropylene) film bag and storing at three temperatures (5oC, 15oC, and 25oC). As control, the cabbage was packaged in a corrugated paper box and stored at 25oC. At the storage temperature of 5oC, the degree of freshness, weight loss, hue angle and SPAD on cabbage packaged with PP film bag maintained its good quality and exhibited a longer period of marketable life compared to the samples stored in other treatments. Results showed that the use of PP film packaging and storing at 5oC could be the optimum condition for commercial storage of ‘Mats-kyeong-chae’. Further investigation on other quality parameters according to different packaging methods would be useful in maintaining the quality of ‘Mats-kyeong-chae’ at postharvest stages.

Effects of microperforated polypropylene film packaging on mangosteen fruits quality at low temperature storage

Effects of microperforated polypropylene film packaging on mangosteen fruits quality at low temperature storage

A comparative study on the effectiveness of ozonated water and peracetic acid in the storability of packaged fresh-cut melon.

Ozonated water and peracetic acid were tested as sanitizers to enhance the storability of fresh-cut melon cubes. Sanitizers were also combined with suitable packaging materials (polypropylene and polylactic acid based plastic films). Fresh-cut melon cubes were stored at 4°C for up to 7 days. Ozonated water and peracetic acid treatments were given by dipping cubes into 0.8ppm O3 and 100ppm Tsunami 100™ solutions, respectively, for 3min. Both sanitizers exhibited efficiency in reducing the total microbial counts on melon cubes (< 2 log CFU g(-1)). Respiratory activity and ethylene production were both affected by the interaction between the sanitizer and the packaging used. Carbon dioxide and oxygen reached 9.89 kPa and 12.20 kPa partial pressures, respectively, using peracetic acid treatment in combination with polypropylene film packaging, consequently developing off-odors starting from day 3. Strong color changes were noted in cubes stored in polylactic acid packaging after 7 days of storage, affecting the sensory quality of the melon cubes. Sensory evaluation (overall visual quality) indicated loss in flavor in the polypropylene packaging. The overall visual quality started to decline on 3rd day because of the development of translucency.Overall, the use of ozone in combination with polypropylene packaging provided the best solution to maintain the quality of melon cubes for up to 5 days of storage at 4°C.

절단배추의 포장재질에 따른 단기 저장 중 품질특성

Fresh cut vegetables provide convenience and rapidity to consumers. However, they have a weakness with respect to their short shelf-life due to browning and quality degradation via increased respiration. To overcome this problem, the effect of packaging film on the short-term storage of cut kimchi cabbages was investigated. Polypropylene (PP), oriented polypropylene (OPP), and low-density polyethylene (LDPE) films were used as packaging film, and cut kimchi cabbages were stored in the packaging films at 5°C for 4 weeks. PP film packaging showed the least weight loss and soluble solids loss after 4 weeks. Titratable acidity increased during storage for all samples, however, the increase rate of titratable acidity in PP and OPP film packaging decreased, which was lower than that of LDPE film packaging. Color values decreased over time during storage. In appearance, PP film packaging was better than other films due to their high transparency. In a sensory test, there was no statistical difference among samples. Taken together, the transparent PP film packaging was more effective for short-term storage of cut kimchi cabbages. Thus, this study provides useful information for the selection of packaging materials for cut kimchi cabbage marketing.

Effect of storage in packaging with oxygen absorbers on the quality of cut gladiolus ‘Princess Summer Yellow’ spikes

Polypropylene film packaging combined with oxygen absorbers was investigated for maintaining the quality of cut gladiolus ‘Princess Summer Yellow’ spikes after storage for 6d. Both the oxygen and carbon dioxide concentrations within the polypropylene bags were lower with oxygen absorbers compared to packaging only. In packaging with oxygen absorbers, the number of florets that opened and wilted increased more slowly, and the vase life of cut spikes was longer than those in only packaging after storage at 15°C or 20°C. Both oxygen absorbers and cut gladiolus spikes themselves produced ethylene during storage. The ethylene concentration in the plastic bags tended to be high when they contained two oxygen absorbers, and low after pretreatment with silver thiosulfate complex (STS). Treatment with STS before packaging improved the floret opening ratio per spike after storage at 15°C. These results suggest that plastic film packaging with oxygen absorbers is an easy way to decrease the oxygen concentration and maintain the quality of cut gladiolus spikes, and that pretreatment with STS improves bud opening after suboptimal temperature storage.

Biochemical and physiological changes in Fenugreek (Trigonella foenum- graecum L.) leaves during storage under modified atmosphere packaging

Fenugreek (Trigonella foenum-graecum L.), is a highly respiring leafy vegetable enriched with many nutrients and other active ingredients such as protein, vitamin C, niacin, potassium, alkaloids, lysine and L-tryptophan as well as steroidal saponins which are beneficial for human health. Both, quantitative and qualitative losses in this vegetable can be reduced by appropriate packaging and storage techniques which have not been applied hitherto. This study was taken upon to assess the potential of macro-perforated MAP for storage of fenugreek leaves. Packages (bag area: 0.075m(2)) made from polypropylene (PP) film (Thickness: 35μmm) were selected for the storage studies. The leaves were packaged in macro-perforated (2 perforations, perforation diameter: 0.3mm each, with and without mustard seeds as natural absorbents) as well as in non-perforated PP film packages with and without mustard seeds. 10g of mustard seeds were placed inside the packages to check water accumulation. The packaged samples were stored for 6days at 75% relative humidity (RH) at 15°C to check water accumulation, if any. Different physiological and biochemical characteristics which generally affect the post-harvest life of the produce were monitored during the storage period. Results of the study suggested that among all the treatments, packaging of fenugreek in two perforation packets with mustard seeds resulted inbest maintenance of chlorophyll, ascorbic acid, phenols and aroma. Water accumulation was also consoled due to mustard seeds after 6days of storage.

PACKAGE HEADSPACE DYNAMICS FOR BABY CORN UNDER MODIFIED ATMOSPHERE PACKAGING WITH MACROPERFORATIONS

ABSTRACTBaby corn is highly perishable and requires appropriate postharvest technologies such as modified atmosphere packaging (MAP) to extend its shelf ife and maintain the nutritional content. However, MAP requires repetitive experimentation to arrive at suitable desired in‐pack partial pressures of O2 and CO2 for application of appropriate MAP mode viz. nonperforated, macroperforated or microperforated one. Microperforated MAP is an expensive proposition and so far has limited commercial applicability, except for high‐value commodities; therefore, macroperforated MAP is being tried to achieve higher gaseous diffusion across the film packages. Predictive modeling represents a physical phenomenon by means of mathematical equations; whose numerical solution can reliably predict transient and steady‐state parameters in a dynamic system and can avoid the need of repetitive experimentation. However, representation of the respiratory behavior of a crop is also of utmost importance as wrong selection or very straightforward assumptions can lead to inadequate predictions. In this study, the respiratory behavior and associated inhibition by CO2 as per established enzyme kinetics theory was first assessed within the temperature range of 5–15C for baby corn; which was then used to model‐predict the in‐pack partial pressures of O2 and CO2 at 10 and 15C; in nonperforated and macroperforated polypropylene film packages; utilizing baby corn, polymeric film, package and the storage environment parameters as input. Model validation during actual storage at 10 and 15C indicated that the model‐predicted, in‐pack partial pressures of O2 and CO2 agreed fairly well with the experimental observations at the selected temperatuers, which showed the appropriateness of the evaluated inhibitory mechanism of headspace CO2.PRACTICAL APPLICATIONSBaby corn has high rates of respiration and requires specialized packaging such as microperforated or macroperforated polymeric film packaging to affect larger gaseous diffusion to extend its shelf life and maintenance of various physicochemical constituents under modified atmosphere packaging (MAP). As microperforated films are economically unviable in certain situations, the objective can be met through application of macroperforated films having customized macroperforations. However, the package headspace dynamics vary with the number of macroperforations. For a particular crop, the number of macroperforations required to generate the ideal in‐pack partial pressures of O2 and CO2 can be suitably predicted with this model, knowing the respiratory behavior and the kind of inhibition by CO2 experienced. Thus, results of the study have a potential application at the level of design of MAP for various crops requiring macroperforated packaging as well as these can be utilized alike for further academic interest in the area of packaging of fresh fruits and vegetables; using predictive modeling approach.

EFFECT OF MODIFIED ATMOSPHERES ON PIGMENT AND ANTIOXIDANT RETENTION OF BETEL LEAF (PIPER BETEL L.)

ABSTRACT Betel leaves were stored for 10 days at 20C under modified atmosphere packaging (MAP) to assess the impact of differential in-pack gaseous atmospheres on the pigments and an antioxidant. Under all the packaging treatments, chlorophyll was maintained during the entire storage period, and the final retention levels were highly influenced by package headspace atmosphere dynamics. Among different packaging treatments, the in-pack partial pressures of 2.5 kPa for O2 and 6.2 kPa for CO2, respectively, for the film packages containing 750 g of betel leaves, resulted in better retention of chlorophyll. The β-carotene content remained largely unaffected. Results suggested that although the build-up of CO2 is necessary for the prevention of browning and maintenance of chlorophyll in the betel leaves. However, either the packaging film with appropriate permeabilities for O2 and CO2 or in-pack weight of betel leaves might be such that equilibrated O2 partial pressures could be still higher (9 kPa) to effect only a beneficial increase in the phenolic content. PRACTICAL APPLICATIONS Betel leaf has an enormous market around the world, and the crop, worth billions of Indian Rupees, is exported from India. Traditional packaging, handling, storage and transportation techniques reduce the shelf life and its various nutritional and phytochemical components. This research has focused on the application of modified atmosphere packaging (MAP) technology for the packaging of betel leaf for retail handling and storage, which is, at present, carried out in ice boxes or gunny bags. The results of the study have implied that the pigments and phenolic content of betel leaf can be sufficiently maintained in polypropylene film packages, which shows the potential of MAP for the packaging of betel leaf. Utilization of the results of this research is likely to benefit the wholesaler and the retailer in the value chain to better maintain its shelf-life and various physicochemical properties, as compared with that obtained using traditional storage techniques.

AN EMPIRICAL APPROACH FOR ASSESSMENT OF SAFE STORAGE PERIOD FOR BUTTON MUSHROOM (AGARICUS BISPORUS) BASED UPON COLOR CHANGES UNDER MODIFIED ATMOSPHERE PACKAGING

ABSTRACT White button mushroom accounts for 35–45% of the total mushroom produced in the world. Modified atmosphere packaging or MAP is a technology that, along with low temperature storage, helps in extending the shelf life and maintenance of quality of the produce packaged in polymeric films. The present study mathematically modeled the various transport processes associated with the mushroom under MAP at 15C and 75% relative humidity (RH) using the enzyme kinetics approach. Low density polyethylene (LDPE), polypropylene (PP) and oriented polypropylene (OPP) films were used to pack the mushroom. Numerical solutions to the transient state equations were programed in a computer programing language to predict the in-pack gaseous partial pressures at any instant of time. The model was experimentally validated, and a simple qualitative tool based upon optimum whiteness of mushroom was developed using the predictions to determine the safe period of storage. The predicted and experimental in-pack partial pressures of O2 and CO2 were in fair agreement with each other. In the OPP film packages, the O2 and CO2 levels stabilized around 6.87 and 12.93 kPa, respectively. Whereas, O2 levels decreased drastically in LDPE and PP film packages. A combination of predicted in-pack environment in all the film packages, storage time and whiteness of mushroom led to the conclusion that mushrooms can be stored safely for 32, 44 and 108 h in the gaseous environment available in the LDPE, PP and OPP film packages, respectively. PRACTICAL APPLICATIONS The empirical approach followed in this study through assimilation of various transient state in-pack variables with a single qualitative attribute of mushroom can serve as a measure of assessment of the mushroom's safe storage period under modified atmosphere packaging. Further, the mathematical approach suggested in this study can also serve as a benchmark for its application to other fruits and vegetables, taking into consideration their respective limiting qualitative characteristics. Thus, the results detailed in the study can be easily applied for their direct practical application during storage as well as for further academic exercises.

Chromatic Changes in Broccoli (Brassica oleracea italica) under Modified Atmospheres in Perforated Film Packages

Broccoli was stored under modified atmosphere packaging (MAP) at 20 °C in perforated and unsealed polypropylene film packages for a storage period of 10 days to evaluate the effect of modified atmospheres on the chromatic changes. At the end of storage, MAP resulted in differential changes in the original green color of broccoli under different packaging treatments. Instead of conventional CIELAB color space system utilizing only L*, a* and b* values, the chromatic changes were analyzed as per L*C*h* color space system using lightness, chroma, and hue angle values to evaluate the final hue (color) along with its associated attributes. On 10th day of storage, broccoli samples kept under different modified atmospheres were observed to be yellow-green only for 4 holes, but between yellow-green and yellow for 8, 12, and 16 hole treatments, respectively. Further, the saturation of final hue attained under different packaging treatments kept on increasing in the order of 4, 8, 12, and 16 holes. On the other hand, broccoli kept in air in unsealed packages turned orange-yellow with higher saturation as compared with MAP samples. The direction of color difference for different treatments with respect to fresh broccoli samples was observed as light and the degree of color difference indicated that 4 and 8 hole treatments were only slight and medium light, respectively. The 4 hole treatment had best color retention as it had slightly saturated yellow-green hue, which was only slightly lighter than the fresh broccoli. Also, the results of sensory and visual analysis confirmed the results obtained from L*C*h* color space diagram and indicated that the modified atmosphere (6.1% O2 and 9% CO2) generated inside the perforated film packages having 4 macro-holes was the most suitable in maintaining the chromatic quality of the broccoli heads.

Qualitative and Textural Changes in Fresh Okra Pods (Hibiscus esculentus L.) under Modified Atmosphere Packaging in Perforated Film Packages

Improper post-harvest handling and storage under room temperature lead to high loss of moisture resulting in loss of strength and development of flaccidity in okra tissues, apart from the loss of its characteristic green color. In this study, different weights of freshly harvested okra pods (Hibiscus esculentus L.) were stored at 15°C and 75% relative humidity packaged under modified atmosphere (MAP) in 35 μm thick polypropylene film packages to assess the effect of different in-pack gaseous compositions of O2 and CO2 on the properties of okra. During storage, the normal freshness indicators of okra namely, the bright green color and ease of snapping at the tip served as the prominent qualitative and textural parameters, indicative of the acceptability of okra. Results indicated that an in-pack gaseous range for O2 (6.3-8.4%) and CO2 (10.7-11.8%) under MAP resulted in maintenance of green color and β-carotene in the pericarp, and ascorbic acid in the seeds as well as other qualitative parameters. Further, the texture analysis of okra at the pre-determined snapping point at the tip and also along the longitudinal portion showed that MAP stored okra were snapping easily at the tips and had a very slight increase in the other mechanical properties which were considered to be within acceptable limits.

Transient state in-pack respiration rates of mushroom under modified atmosphere packaging based on enzyme kinetics

The evaluation of transient-state in-pack respiration rates for oxygen (O2) consumption and carbon dioxide (CO2) evolution at any instant of time for a commodity packaged in polymeric film packages and kept under modified atmosphere (MA) for long-term storage requires regular analysis of the in-pack partial pressures of O2 and CO2. Enzyme kinetic theory has been observed to make near-accurate predictions of the respiration rates of many commodities under MA. This approach was followed to evaluate the respiration rates of the ‘button’ mushroom, packaged in low-density polyethylene (LDPE), polypropylene (PP) and oriented polypropylene (OPP) film packages at any instant of time, utilising the produce, package and the environmental parameters. The respiration model parameters under the specified environmental conditions of 15 °C and 75% relative humidity (RH) were evaluated using multiple regression analysis and were utilised to know the predicted rates of respiration for O2 consumption and CO2 evolution. The experimental in-pack partial pressures of O2 and CO2 under all the packaging treatments agreed fairly well with the predicted values for a storage period of 96 h. The predicted rates of respiration dropped drastically in LDPE and PP film packages, but arrived to near-constant levels (115 and 110 ml kg−1 h−1 for the O2 consumption and CO2 evolution, respectively) in the OPP film packages after 36 h, indicating the condition of gaseous equilibrium in these packages. Results of the study confirm that the enzyme kinetics approach can be used to predict the respiration rates of any commodity under MA in polymeric films.

Modified Atmosphere Packaging of Cut Welsh Onion: Effect of Micro-Perforated Polypropylene Film Packaging on Chemical Components and Quality Stability of the Vegetable.

The chemical components and quality stability of pre-cut Welsh onion wrapped in an unperforated or micro-perforated orientated polypropylene (OPP) film package were evaluated during storage at 10°C. The concentration of oxygen (O2) in the unperforated OPP package decreased rapidly to 2% while that of carbon dioxide (CO2) increased. Therefore, the onion underwent anaerobic respiration, ethyl alcohol was produced and some of the chemical components were lost. Moreover the cellular tissue of the vegetable became water-soaked. The O2 concentration in the OPP film package with too many micro-perforations decreased slightly, so that ethyl alcohol was not detected but there was a loss of chemical components. The quality of the product was diminished and the onion was unmarketable after 6 days of storage. For cut Welsh onion packed in perforated OPP film (with 24 micro-perforations), the O2 concentration in the package was not as low as in the modified atmosphere packaging for onion, but did decrease to 10%. Ethyl alcohol could not be detected and there was no or only slight loss of chemical components, so that the onion was still marketable after 6 days of storage.

Effect of Polypropylene Film Packaging and Storage Temperature on Chemical Components and Quality Stability of Welsh Onion.

Chemical components and quality of Welsh onion (Allium fistulosum L.) wrapped roughly or completely heat-sealed with orientated polypropylene (OPP) film were investigated during storage at 5 and 20°C. Concentrations of oxygen (O2) and carbon dioxide (CO2) in the roughly heat-sealed packages were the same as in air, whereas O2 concentration in the completely heat-sealed packages decreased to 2-3% at 20°C and to 4-5% at 5°C. Contents of reduced ascorbic acid (RAA) and chlorophyll in onion which was roughly sealed and stored at 20°C decreased, and withering of leaf tip occurred. This meant that the quality deteriorated severely. However, the contents of RAA and chlorophyll in Welsh onions which were sealed completely and stored at 20°C, and which were sealed roughly or completely and stored at 5°C, did not change or only slightly decreased. In Welsh onion sealed completely and stored at 20°C, off-odor was detected after 2 days and severely after 7 days and leaf tips began to wither after 7 days, suggesting that quality could be kept only for 4 days storage. In Welsh onion sealed completely and stored at 5°C, off-odors and withering of leaf tip was not observed for 9 days, indicating that quality marketability could be kept for that period.