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Gas Transmission Rates Across ‘Carabao’ Mango (Mangifera Indica L.) Peel at Different Stages of Maturity and Ripeness
Available online at www.sciencedirect.com
ScienceDirect APCBEE Procedia 8 (2014) 230 – 235
2013 4th International Conference on Agriculture and Animal Science (CAAS 2013) 2013 3rd International Conference on Asia Agriculture and Animal (ICAAA 2013)
Gas Transmission Rates Across ‘Carabao’ Mango (Mangifera indica L.) Peel at Different Stages of Maturity and Ripeness Fidelina T. Floresa , Kevin F. Yaptencob, Engelbert K. Peraltab, Edralina P. Serranoc b
a Graduate School, University of the Philippines Los Baños, Laguna 4031, Philippines College of Engineering and Agro-Industrial Technology, University of the Philippines Los Baños, Laguna 4031, Philippines c College of Agriculture, University of the Philippines Los Baños, Laguna 4031, Philippines
Abstract Gas transmission rate through fruit peel is needed to understand gas exchange between fruit and the environment. It can be used to design packaging material and formulate edible coatings to be used by the fruit. It can also be used to predict oxygen consumption and possible carbon dioxide injury which could affect ripening and could predict the internal gas level inside the fruit. Oxygen and carbon dioxide transmission rates (O2TR and CO2TR) of mango (Mangifera indica, L.) peel at different stages of maturity and ripeness which were stored under two temperature regimes were measured using gas diffusion chamber. Nitrogen gas was flushed inside the chamber to decrease the oxygen level. Then a gas mixture of known concentration was flushed in the chamber and the concentration inside the chamber was measured through time. The Exponential Decay Method of Gas Transmission Rate of Films as described by Moyls (1992) was used to relate partial pressure of the gas concentration inside the chamber and the outside condition. Results showed that overmature fruit peel-PCI3 under 27°C had the highest O2TR and CO2TR (1.636 mLO2/cm2-hr - 4.744 mLCO2/cm2-hr) while immature fruit peel-PCI1 under 14°C had the lowest O2TR and CO2TR (1.104 mLO2/cm2-hr - 3.321 mLO2/cm2-hr). At constant temperature, gas transmission rates increase with maturity and as the fruit peel turns yellow. © 2013 2014 The Authors. by Published by Elsevier B.V. Thisand/or is an open access article underresponsibility the CC BY-NC-ND license © Published Elsevier B.V. Selection peer review under of Asia-Pacific (http://creativecommons.org/licenses/by-nc-nd/3.0/). Chemical, Biological & Environmental Engineering Society
Selection and peer review under responsibility of Asia-Pacific Chemical, Biological & Environmental Engineering Society
Keywords: oxygen and carbon dioxide gas transmission rates, mango, peel, maturity, ripeness
1. Introduction Physiological process like respiration occurs in the fruit and can affect postharvest losses. Effects may
Corresponding author. Mobile: 09174731936 E-mail address: [email protected]
2212-6708 © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Selection and peer review under responsibility of Asia-Pacific Chemical, Biological & Environmental Engineering Society doi:10.1016/j.apcbee.2014.03.032
Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
include loss of weight due to water loss, color deterioration, change in size and shape, taste or flavor and others. These are customers’ basis for buying and consuming the commodity in the market [1]. Gas exchange between the commodity and surrounding environment affects physiological processes. The atmosphere in the product package is affected by the interaction of factors that include the permeability of the package, behavior of the plant material and the environment, gas transmission rate of barriers such as the peel of the fruit and the packaging material used. The peel of the fruit serves as a medium for gas exchange between the commodity and the environment. It plays an important role in controlling physiological processes. Gas exchange in fruits can be approximated using Fick’s first law. This law states that the flux of gas which diffuses through a barrier is dependent on the fruit thickness, area of the barrier and its resistance, and the difference in concentration of gases between the two sides of the barrier. The rates at which carbon dioxide and oxygen diffuse into and out of the fruit can determine the gas level in the internal region of the fruit [2]. Resistance to gas diffusion of fruits or vegetables varies on the type of commodity, cultivar, handling and stage of maturity [3]. The structure of these barriers like the fruit peel is believed to affect gas exchange in the tissue and also with the surroundings. Knowing the transmission rate of mango peel at different maturity and at early stage of ripeness will also help in determining the suitable packaging material to be used in storing the commodity at that given stage of growth and formulate compatible edible coatings for the commodity. Thus, it can affect the shelf life of the commodity. The objectives of this study were to determine the oxygen and carbon dioxide transmission rates of mango peel at different stages of maturity and ripeness and to determine the effect of maturity and stage of ripeness on oxygen and carbon dioxide transmission rates of mango peel. 2. Materials and Methods 2.1. Fruit Samples Mango samples were manually harvested from a farm in Barangay Sirang-Lupa, Calamba City Philippines. Maturity was based on the days after flower induction (DAFI). Samples used were at 110 DAFI for immature, 115 DAFI for mature and 120 DAFI for overmature. Stage of ripeness was from full green stage (PCI 1), breaker - not more than 10% yellow (PCI 2) and more green than yellow (PCI 3). Weight and volume of each fruits in a lot was measured using an electronic balance and water displacement method, respectively. 2.2. Gas Diffusion Chamber and Peel Samples Design of the gas diffusion chamber was adapted from Malilay et.al [4]. Gas diffusion chamber was made from polyvinyl chloride (PVC) pipe, clear acrylic sheet and galvanized iron sheet. There were three holes on the acrylic sheet where the peel samples were placed. A PVC rod was used for the sample cover. Rubber septums were inserted into the two holes on the side of the gas chamber. Metal screws hold the sample cover and the acrylic sheet. Sufficient amount of Dow Corning vacuum grease was applied between the sample holder and acrylic sheet. A cross section drawing of the design of the gas chamber was shown in Fig. 1. Cylindrical disc corer made from stainless steel was used to take peel samples from the fruit surface with a thickness of 1.5mm. Gas diffusion chambers were tested for leakage for a period of 24 hours. 2.3. Gas Transmission Rate by Exponential Decay Method 2.3.1. Gas Flushing and Sampling Gas chambers were flushed with pure N2 until the O2 level inside the chamber was approximately 5% followed by a gas mix of 5% O2 and 5% CO2 from a gas mix tank. The gas chambers were placed in a cold room at 14°C and in ambient under 27°C. The air temperature and relative humidity in the cold room and
231
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Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
ambient was measured using a TinyTag Ultra 2 data logger. The gas concentration inside the gas chamber was measured using a gas analyzer (PBI DanSensor Checkmate 3) for every hour for 7 hours. When the peel color of the mangoes left at the cold room and ambient changed, the peel samples on the chambers were replaced.
Fig. 1. Cross - section of the gas chamber.
2.3.2. Gas Transmission Rate Computation Oxygen and carbon dioxide transmission rates was computed using the Exponential Decay Method as described by Moyls [5], where the Fick’s law was modified to relate gas transmission rate with the partial pressures of the gas composition inside the test cell which was the gas chamber and the condition outside. The computed O2 and CO2 pressure measurements based on the Ideal Gas Law was plotted as ln (ΔP/ΔP°) versus time using Microsoft Excel. The slope of the line “S” was the exponential decay constant of the partial pressure difference across the peel. And the final resulting equation, which is the transmission rate, will be: ܶݏ݊ܽݎሺ
మ
ሻ ൌ
ିୗ౪౨౩
(1)
2.4. Statistical Analysis The statistical analyses were done using the STATISTICA 7. Analysis of variance (ANOVA) was used to evaluate the variation between measurements and significant difference were analyzed using the Tukey's Honestly Significant Difference (HSD) Test. 3. Results and Discussion 3.1. Gas Transmission Rate by Exponential Decay Method 3.1.1.Gas Concentration Over mature mango peel at PCI 3 and stored at ambient condition has the highest O2 TR M and CO2 TR M and immature mango peel at PCI1 and stored in a cold room has the lowest O2 TR M and CO2 TR M (Table 1). Analysis of variance shows that maturity, temperature and stage of ripeness has a significant effect on O 2 TR M and CO2 TR M. That is, as the fruit start to ripen, gas exchange across the peel increases. Also storage at low temperature decreases the gas exchange. This might be due to the structure and arrangement of the
233
Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
cells in the peel of fruit at different maturity and stage of ripeness. Table 1. Gas transmission rates of mango peel at different maturity and peel color index under two temperature regimes.
PCI
Maturity
Immature Mature Overmature Immature 2 Mature Overmature Immature 3 Mature Overmature Means within group (HSD) at 5% level. 1
Transmission Rates @ 14°C Transmission Rates @ 27°C (mL O2/cm2 hr) (mL CO2/cm2 hr) (mL O2/cm2 hr) (mL CO2/cm2 hr) Mean SE Mean SE Mean SE Mean SE 1.10 ± 0.04 a 3.32 ± 0.13 a 1.19 ± 0.02 b 3.20 ± 0.15 1.11 ± 0.04 a 3.51 ± 0.18 a 1.43 ± 0.02 a 3.76 ± 0.17 1.18 ± 0.03 a 3.43 ± 0.08 a 1.36 ± 0.04 a 3.87 ± 0.15 1.29 ± 0.07 a 3.35 ± 0.05 a 1.31 ± 0.05 a 3.54 ± 0.10 1.42 ± 0.04 a 3.83 ± 0.18 a 1.45 ± 0.04 a 4.19 ± 0.18 1.38 ± 0.07 a 3.69 ± 0.17 a 1.42 ± 0.07 a 4.41 ± 0.19 1.49 ± 0.04 a 3.64 ± 0.13 a 1.56 ± 0.05 a 4.37 ± 0.25 1.49 ± 0.07 a 4.09 ± 0.23 a 1.58 ± 0.03 a 4.70 ± 0.21 1.61 ± 0.06 a 4.26 ± 0.18 a 1.64 ± 0.09 a 4.74 ± 0.14 in a column followed by a common letter do not differ with at Tukey’s Honest Significance Difference
a a a b ab a a a a
A study by Mendoza [6] further explained arrangement of cells during the stage of fruit development saying that at the early stage of mango fruit development, the epidermal cells are elongated radially. As the fruit starts to mature, the epidermal cells become disorganized. Yashoda et. al [7] observed that cell wall of mango is more compact and rigid at the mature unripe stage and appeared loosely structured and expanded with considerable degree of swelling at the end of ripening. Rodriguez, et.al [8] observed that resistance to gas diffusion increases at the climacteric rise and decrease after or when the fruits start to soften and become overripe. Induction of cellulose and pectinase enzymes may be responsible for cell separation through breakdown of middle lamella. This affects cell solutes leakage and water logging of intercellular spaces. These changes restrict movement of gases within the fruit. 3.2. Edible Coating Matching For application of edible coating on mango fruit at green mature stage stored at 14°C, the recommended storage condition for mango at modified atmosphere packaging is 5%O2 and 5%CO2 [9]. Using the respiration rate (52.057 mL O2/kg h and 32.244 mL C O2 / kg hr), weight (0.209 kg), surface area of fruit for gas exchange (188.507 cm2) and condition of air outside (21% O2 and 0.003% C O2), required oxygen and carbon dioxide gas transmission rate is computed using Equation 12 and 13. The required oxygen and carbon dioxide gas transmission of the fruit (0.361 mL O2/cm2 hr and 0.716 mL CO2/cm2 hr) is lower than the transmission rate of the peel; an edible coating is needed to restrict gas exchange between the fruit and the working environment. Following the method as described by Hagenmaier and Shaw [10], the required transmission rate of the edible coating is computed. The recommended oxygen and carbon dioxide gas transmission rate of the coating is 0.534 mL O2/cm2 hr and 0.899 mL CO2/cm2 hr, respectively. Table 2 shows the values of transmission rates of some edible films. Base on the table, the nanomultilayer can be used with a thickness 2.03x10-4 mm, but the oxygen transmission rate of this very low (0.111 mL O2/cm2 hr). Low oxygen transmission can cause the product to undergo anaerobic respiration. On the other hand, the oxygen transmission rate of starch at 1.02 x10-4 mm can be used is within the recommended value but the carbon dioxide transmission rate of this coating must be checked also. The computed oxygen and carbon dioxide gas transmission rate of the edible coating may be used as a guide in formulating an edible coating to be used by the fruit.
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Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
Table 2. Transmission rates of selected edible coating. Transmission Rate Edible Coating
-4
@ 1.78 x10-4 mm
@ 2.54x10 mm 2
2
2
Source 2
mL O2/cm hr mL CO2/ cm hr mL O2/ cm hr mL CO2/ cm hr Waxes, natural and synthetic, and fatty acids
0.089
0.720
0.127
1.028
Hagenmaier and Shaw [10]
Nanomultilayer – 5 layers (Pectin and chitosan)
0.001
0.446
0.001
0.637
Medeiros, et.al [11]
Starch
0.216
-
0.308
-
McHugh and Krochta, [12]
4. Summary and Conclusions Gas transmission rate of the barriers like the fruit peel is important in designing the packaging material and formulating edible coatings to be used. Oxygen and carbon dioxide transmission rates of mango peel at different maturity stages and peel color index stored under two temperature regimes were determined using Exponential Decay Method. Results showed that maturity, storage temperature and stage of ripeness had a significant effect on oxygen and carbon dioxide transmission rate of mango peel. As the fruit matures and start to ripen, the gas transmission rate of the peel also increases and storage at low temperature can lower the rate of gas transmission across peel. Oxygen and carbon dioxide transmission rates of the mango peel were not greatly affected by maturity at the early stages of ripeness. Oxygen and carbon dioxide transmission rates across the peel that measured directly were higher than the computed values using the respiration mass balance. This might be due to some errors that accumulated while measuring the parameters. Acknowledgements The authors would like to thank the Engineering Research and Development Technology – Department of Science and Technology for financially supporting the study and the staff of Postharvest Training and Research Center of the Crop Science Cluster, College of Agriculture for the assistance during the experiment. References [1] Wills, R.H.H., Lee, T.H., Graham, D., McGlasson, W.B. and Hall, E.G. 1981. Postharvest An Introduction to the Physiology and Handling of Fruits and Vegetables. New South Wales University Press. Australia. p. 60-61 and 63 [2] Zhang, J. and Bunn, J.M. 1999. Oxygen Diffusivities of Apple Flesh and Skin. Transactions of the American Society of of Agricultural Engineers Vol. 43 (2) : 359-363 [3] Irtwange, S. V. February 2006. Application of Modified Atmosphere Packaging and Related Technology in Postharvest Handling of Fresh Fruits and Vegetables Agricultural Engineering International: the CIGR E-Journal. Invited Overview No. 4. Vol. VIII [4] Malilay, I. X. R. Yaptenco, K.F., Casas, E.V and Elepaño, A. R. 2011. Gas Transmission Rates of Unperforated and Perforated Polyethylene Films for Modified Atmosphere Packaging Application. Philippine Journal of Agricultural and Biosystems Engineering. AMDP CEAT, UP Los Baños. Vol. IX. 2011 Issue. p. 51-59 [5] Moyls, L., Hocking, R., Beveridge, T., and Timbers, G., 1992. Exponential Decay Method for Determining Gas Transmission Rate of Films. In Transactions of the American Society of Agricultural Engineers. 35 (4): 1259-1265
Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
[6] Mendoza, D. B. Jr. 1981. Development Physiology of ‘Carabao’ Mango (Mangifera indica L.) fruits. PhD Thesis, UP Los Baños.172 p. [7] Yashoda, H.M., Prabha, T.N. and Tharanathan, R.N. 2006. Mango Ripening: Changes in Cell Wall Constituents in Relation to Textural Softening. Journal of the Science of Food and Agriculture 86 : 713–721 [8] Rodriguez, L., Zagory, D. and Kader, A.A. 1989. Relation Between Gas Diffusion Resistance and Ripening in Fruits. p.1-7. In: J.K. Fellman (ed.) Proceedings of the Fifth International Controlled Atmosphere Research Conference (June 14-16, 1989. Wenatehee, WA) Vol.2 [9] Kader, A. A. 1994. Modified and Controlled Atmosphere Storage of Tropical Fruits. In Postharvest Handling of Tropical Fruits. ACIAR Proceedings No.50 Chiang Mai, Thailand. p. 239 and 242 [10] Hagenmaier, R.D. and Shaw, P. E. 1992. Gas Permeability of Fruit Coating Waxes. Journal of American Society of Horticultural Science 117(1):105-109 [11] Medeiros, B., Pinheiro, A., Carneiro-da-Cunha, M. and Vicente, A. 2012. Development and Characterization of a Nanomultilayer Coating of Pectin and Chitosan – Evaluation of its Gas Barrier Properties and Application on ‘Tommy Atkins’ Mangoes. Journal of Food Engineering 110 : 457–464 [12] McHugh, T. and Krochta, J. 1994. Permeability Properties of Edible Films. In: Edible Coatings and Films to Improve Food Quality. J.M. Krochta, E.A.Baldwin, and M. Nisperos-Carriedo. Technomic, Lancaster PA pp. 139 and 148
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ScienceDirect APCBEE Procedia 8 (2014) 230 – 235
2013 4th International Conference on Agriculture and Animal Science (CAAS 2013) 2013 3rd International Conference on Asia Agriculture and Animal (ICAAA 2013)
Gas Transmission Rates Across ‘Carabao’ Mango (Mangifera indica L.) Peel at Different Stages of Maturity and Ripeness Fidelina T. Floresa , Kevin F. Yaptencob, Engelbert K. Peraltab, Edralina P. Serranoc b
a Graduate School, University of the Philippines Los Baños, Laguna 4031, Philippines College of Engineering and Agro-Industrial Technology, University of the Philippines Los Baños, Laguna 4031, Philippines c College of Agriculture, University of the Philippines Los Baños, Laguna 4031, Philippines
Abstract Gas transmission rate through fruit peel is needed to understand gas exchange between fruit and the environment. It can be used to design packaging material and formulate edible coatings to be used by the fruit. It can also be used to predict oxygen consumption and possible carbon dioxide injury which could affect ripening and could predict the internal gas level inside the fruit. Oxygen and carbon dioxide transmission rates (O2TR and CO2TR) of mango (Mangifera indica, L.) peel at different stages of maturity and ripeness which were stored under two temperature regimes were measured using gas diffusion chamber. Nitrogen gas was flushed inside the chamber to decrease the oxygen level. Then a gas mixture of known concentration was flushed in the chamber and the concentration inside the chamber was measured through time. The Exponential Decay Method of Gas Transmission Rate of Films as described by Moyls (1992) was used to relate partial pressure of the gas concentration inside the chamber and the outside condition. Results showed that overmature fruit peel-PCI3 under 27°C had the highest O2TR and CO2TR (1.636 mLO2/cm2-hr - 4.744 mLCO2/cm2-hr) while immature fruit peel-PCI1 under 14°C had the lowest O2TR and CO2TR (1.104 mLO2/cm2-hr - 3.321 mLO2/cm2-hr). At constant temperature, gas transmission rates increase with maturity and as the fruit peel turns yellow. © 2013 2014 The Authors. by Published by Elsevier B.V. Thisand/or is an open access article underresponsibility the CC BY-NC-ND license © Published Elsevier B.V. Selection peer review under of Asia-Pacific (http://creativecommons.org/licenses/by-nc-nd/3.0/). Chemical, Biological & Environmental Engineering Society
Selection and peer review under responsibility of Asia-Pacific Chemical, Biological & Environmental Engineering Society
Keywords: oxygen and carbon dioxide gas transmission rates, mango, peel, maturity, ripeness
1. Introduction Physiological process like respiration occurs in the fruit and can affect postharvest losses. Effects may
Corresponding author. Mobile: 09174731936 E-mail address: [email protected]
2212-6708 © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Selection and peer review under responsibility of Asia-Pacific Chemical, Biological & Environmental Engineering Society doi:10.1016/j.apcbee.2014.03.032
Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
include loss of weight due to water loss, color deterioration, change in size and shape, taste or flavor and others. These are customers’ basis for buying and consuming the commodity in the market [1]. Gas exchange between the commodity and surrounding environment affects physiological processes. The atmosphere in the product package is affected by the interaction of factors that include the permeability of the package, behavior of the plant material and the environment, gas transmission rate of barriers such as the peel of the fruit and the packaging material used. The peel of the fruit serves as a medium for gas exchange between the commodity and the environment. It plays an important role in controlling physiological processes. Gas exchange in fruits can be approximated using Fick’s first law. This law states that the flux of gas which diffuses through a barrier is dependent on the fruit thickness, area of the barrier and its resistance, and the difference in concentration of gases between the two sides of the barrier. The rates at which carbon dioxide and oxygen diffuse into and out of the fruit can determine the gas level in the internal region of the fruit [2]. Resistance to gas diffusion of fruits or vegetables varies on the type of commodity, cultivar, handling and stage of maturity [3]. The structure of these barriers like the fruit peel is believed to affect gas exchange in the tissue and also with the surroundings. Knowing the transmission rate of mango peel at different maturity and at early stage of ripeness will also help in determining the suitable packaging material to be used in storing the commodity at that given stage of growth and formulate compatible edible coatings for the commodity. Thus, it can affect the shelf life of the commodity. The objectives of this study were to determine the oxygen and carbon dioxide transmission rates of mango peel at different stages of maturity and ripeness and to determine the effect of maturity and stage of ripeness on oxygen and carbon dioxide transmission rates of mango peel. 2. Materials and Methods 2.1. Fruit Samples Mango samples were manually harvested from a farm in Barangay Sirang-Lupa, Calamba City Philippines. Maturity was based on the days after flower induction (DAFI). Samples used were at 110 DAFI for immature, 115 DAFI for mature and 120 DAFI for overmature. Stage of ripeness was from full green stage (PCI 1), breaker - not more than 10% yellow (PCI 2) and more green than yellow (PCI 3). Weight and volume of each fruits in a lot was measured using an electronic balance and water displacement method, respectively. 2.2. Gas Diffusion Chamber and Peel Samples Design of the gas diffusion chamber was adapted from Malilay et.al [4]. Gas diffusion chamber was made from polyvinyl chloride (PVC) pipe, clear acrylic sheet and galvanized iron sheet. There were three holes on the acrylic sheet where the peel samples were placed. A PVC rod was used for the sample cover. Rubber septums were inserted into the two holes on the side of the gas chamber. Metal screws hold the sample cover and the acrylic sheet. Sufficient amount of Dow Corning vacuum grease was applied between the sample holder and acrylic sheet. A cross section drawing of the design of the gas chamber was shown in Fig. 1. Cylindrical disc corer made from stainless steel was used to take peel samples from the fruit surface with a thickness of 1.5mm. Gas diffusion chambers were tested for leakage for a period of 24 hours. 2.3. Gas Transmission Rate by Exponential Decay Method 2.3.1. Gas Flushing and Sampling Gas chambers were flushed with pure N2 until the O2 level inside the chamber was approximately 5% followed by a gas mix of 5% O2 and 5% CO2 from a gas mix tank. The gas chambers were placed in a cold room at 14°C and in ambient under 27°C. The air temperature and relative humidity in the cold room and
231
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Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
ambient was measured using a TinyTag Ultra 2 data logger. The gas concentration inside the gas chamber was measured using a gas analyzer (PBI DanSensor Checkmate 3) for every hour for 7 hours. When the peel color of the mangoes left at the cold room and ambient changed, the peel samples on the chambers were replaced.
Fig. 1. Cross - section of the gas chamber.
2.3.2. Gas Transmission Rate Computation Oxygen and carbon dioxide transmission rates was computed using the Exponential Decay Method as described by Moyls [5], where the Fick’s law was modified to relate gas transmission rate with the partial pressures of the gas composition inside the test cell which was the gas chamber and the condition outside. The computed O2 and CO2 pressure measurements based on the Ideal Gas Law was plotted as ln (ΔP/ΔP°) versus time using Microsoft Excel. The slope of the line “S” was the exponential decay constant of the partial pressure difference across the peel. And the final resulting equation, which is the transmission rate, will be: ܶݏ݊ܽݎሺ
మ
ሻ ൌ
ିୗ౪౨౩
(1)
2.4. Statistical Analysis The statistical analyses were done using the STATISTICA 7. Analysis of variance (ANOVA) was used to evaluate the variation between measurements and significant difference were analyzed using the Tukey's Honestly Significant Difference (HSD) Test. 3. Results and Discussion 3.1. Gas Transmission Rate by Exponential Decay Method 3.1.1.Gas Concentration Over mature mango peel at PCI 3 and stored at ambient condition has the highest O2 TR M and CO2 TR M and immature mango peel at PCI1 and stored in a cold room has the lowest O2 TR M and CO2 TR M (Table 1). Analysis of variance shows that maturity, temperature and stage of ripeness has a significant effect on O 2 TR M and CO2 TR M. That is, as the fruit start to ripen, gas exchange across the peel increases. Also storage at low temperature decreases the gas exchange. This might be due to the structure and arrangement of the
233
Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
cells in the peel of fruit at different maturity and stage of ripeness. Table 1. Gas transmission rates of mango peel at different maturity and peel color index under two temperature regimes.
PCI
Maturity
Immature Mature Overmature Immature 2 Mature Overmature Immature 3 Mature Overmature Means within group (HSD) at 5% level. 1
Transmission Rates @ 14°C Transmission Rates @ 27°C (mL O2/cm2 hr) (mL CO2/cm2 hr) (mL O2/cm2 hr) (mL CO2/cm2 hr) Mean SE Mean SE Mean SE Mean SE 1.10 ± 0.04 a 3.32 ± 0.13 a 1.19 ± 0.02 b 3.20 ± 0.15 1.11 ± 0.04 a 3.51 ± 0.18 a 1.43 ± 0.02 a 3.76 ± 0.17 1.18 ± 0.03 a 3.43 ± 0.08 a 1.36 ± 0.04 a 3.87 ± 0.15 1.29 ± 0.07 a 3.35 ± 0.05 a 1.31 ± 0.05 a 3.54 ± 0.10 1.42 ± 0.04 a 3.83 ± 0.18 a 1.45 ± 0.04 a 4.19 ± 0.18 1.38 ± 0.07 a 3.69 ± 0.17 a 1.42 ± 0.07 a 4.41 ± 0.19 1.49 ± 0.04 a 3.64 ± 0.13 a 1.56 ± 0.05 a 4.37 ± 0.25 1.49 ± 0.07 a 4.09 ± 0.23 a 1.58 ± 0.03 a 4.70 ± 0.21 1.61 ± 0.06 a 4.26 ± 0.18 a 1.64 ± 0.09 a 4.74 ± 0.14 in a column followed by a common letter do not differ with at Tukey’s Honest Significance Difference
a a a b ab a a a a
A study by Mendoza [6] further explained arrangement of cells during the stage of fruit development saying that at the early stage of mango fruit development, the epidermal cells are elongated radially. As the fruit starts to mature, the epidermal cells become disorganized. Yashoda et. al [7] observed that cell wall of mango is more compact and rigid at the mature unripe stage and appeared loosely structured and expanded with considerable degree of swelling at the end of ripening. Rodriguez, et.al [8] observed that resistance to gas diffusion increases at the climacteric rise and decrease after or when the fruits start to soften and become overripe. Induction of cellulose and pectinase enzymes may be responsible for cell separation through breakdown of middle lamella. This affects cell solutes leakage and water logging of intercellular spaces. These changes restrict movement of gases within the fruit. 3.2. Edible Coating Matching For application of edible coating on mango fruit at green mature stage stored at 14°C, the recommended storage condition for mango at modified atmosphere packaging is 5%O2 and 5%CO2 [9]. Using the respiration rate (52.057 mL O2/kg h and 32.244 mL C O2 / kg hr), weight (0.209 kg), surface area of fruit for gas exchange (188.507 cm2) and condition of air outside (21% O2 and 0.003% C O2), required oxygen and carbon dioxide gas transmission rate is computed using Equation 12 and 13. The required oxygen and carbon dioxide gas transmission of the fruit (0.361 mL O2/cm2 hr and 0.716 mL CO2/cm2 hr) is lower than the transmission rate of the peel; an edible coating is needed to restrict gas exchange between the fruit and the working environment. Following the method as described by Hagenmaier and Shaw [10], the required transmission rate of the edible coating is computed. The recommended oxygen and carbon dioxide gas transmission rate of the coating is 0.534 mL O2/cm2 hr and 0.899 mL CO2/cm2 hr, respectively. Table 2 shows the values of transmission rates of some edible films. Base on the table, the nanomultilayer can be used with a thickness 2.03x10-4 mm, but the oxygen transmission rate of this very low (0.111 mL O2/cm2 hr). Low oxygen transmission can cause the product to undergo anaerobic respiration. On the other hand, the oxygen transmission rate of starch at 1.02 x10-4 mm can be used is within the recommended value but the carbon dioxide transmission rate of this coating must be checked also. The computed oxygen and carbon dioxide gas transmission rate of the edible coating may be used as a guide in formulating an edible coating to be used by the fruit.
234
Fidelina T. Flores et al. / APCBEE Procedia 8 (2014) 230 – 235
Table 2. Transmission rates of selected edible coating. Transmission Rate Edible Coating
-4
@ 1.78 x10-4 mm
@ 2.54x10 mm 2
2
2
Source 2
mL O2/cm hr mL CO2/ cm hr mL O2/ cm hr mL CO2/ cm hr Waxes, natural and synthetic, and fatty acids
0.089
0.720
0.127
1.028
Hagenmaier and Shaw [10]
Nanomultilayer – 5 layers (Pectin and chitosan)
0.001
0.446
0.001
0.637
Medeiros, et.al [11]
Starch
0.216
-
0.308
-
McHugh and Krochta, [12]
4. Summary and Conclusions Gas transmission rate of the barriers like the fruit peel is important in designing the packaging material and formulating edible coatings to be used. Oxygen and carbon dioxide transmission rates of mango peel at different maturity stages and peel color index stored under two temperature regimes were determined using Exponential Decay Method. Results showed that maturity, storage temperature and stage of ripeness had a significant effect on oxygen and carbon dioxide transmission rate of mango peel. As the fruit matures and start to ripen, the gas transmission rate of the peel also increases and storage at low temperature can lower the rate of gas transmission across peel. Oxygen and carbon dioxide transmission rates of the mango peel were not greatly affected by maturity at the early stages of ripeness. Oxygen and carbon dioxide transmission rates across the peel that measured directly were higher than the computed values using the respiration mass balance. This might be due to some errors that accumulated while measuring the parameters. Acknowledgements The authors would like to thank the Engineering Research and Development Technology – Department of Science and Technology for financially supporting the study and the staff of Postharvest Training and Research Center of the Crop Science Cluster, College of Agriculture for the assistance during the experiment. References [1] Wills, R.H.H., Lee, T.H., Graham, D., McGlasson, W.B. and Hall, E.G. 1981. Postharvest An Introduction to the Physiology and Handling of Fruits and Vegetables. New South Wales University Press. Australia. p. 60-61 and 63 [2] Zhang, J. and Bunn, J.M. 1999. Oxygen Diffusivities of Apple Flesh and Skin. Transactions of the American Society of of Agricultural Engineers Vol. 43 (2) : 359-363 [3] Irtwange, S. V. February 2006. Application of Modified Atmosphere Packaging and Related Technology in Postharvest Handling of Fresh Fruits and Vegetables Agricultural Engineering International: the CIGR E-Journal. Invited Overview No. 4. Vol. VIII [4] Malilay, I. X. R. Yaptenco, K.F., Casas, E.V and Elepaño, A. R. 2011. Gas Transmission Rates of Unperforated and Perforated Polyethylene Films for Modified Atmosphere Packaging Application. Philippine Journal of Agricultural and Biosystems Engineering. AMDP CEAT, UP Los Baños. Vol. IX. 2011 Issue. p. 51-59 [5] Moyls, L., Hocking, R., Beveridge, T., and Timbers, G., 1992. Exponential Decay Method for Determining Gas Transmission Rate of Films. In Transactions of the American Society of Agricultural Engineers. 35 (4): 1259-1265
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