Textural Properties Of Banana (Musa Acuminata) Stored Under Modified Atmosphere Conditions Using Diffusion Channel

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1 Journal of Agricultural Engineering and Biotechnology May 213, Vol. 1 Iss. 1, PP Textural Properties Of Banana (Musa Acuminata) Stored Under Modified Atmosphere Conditions Using Diffusion Channel A.Karthiayani* 1, N.Varadharaju 2, M.Siddharth 3 1 Department of Food Engineering, College of Food and Dairy Technology, Tamilnadu Veterinary and Animal Sciences University, Chennai, India. 2 Department of Food and Agricultural Process Engineering, College of Agricultural Engineering, Tamilnadu Agricultural University, Coimbatore, India. 3 Krishi Vigyan Kendra, Tamilnadu Veterinary and Animal Sciences University, Chennai, India. 1 mankarthi@yahoo.com; 2 nvaradharaju@yahoo.com; 3 siddharth_chennai@yahoo.co.in Abstract-Two varieties of banana (Musa acuminata), Poovan (AB group) and Robusta (AAA group) were stored under modified atmosphere conditions (MA) using diffusion channel at ambient, 24 C and 14 C. The diffusion channels of dimensions (lengths 5, 1, 15 and 2 cm and inner diameters 3, 5 and 7 mm) were chosen for the study. The textural property in terms of firmness were determined using real-time texture analyser (Stable Micro Systems)for the stored fruits at 1 days interval till 2, 3 and 4 days at ambient, 24 C and 14 C respectively. The firmness decreased with the storage period. The penetration force decreased from initial value of 325 g, 329 g to 8.2g, 9.4g for Poovan and Robusta respectively on 4 th day of storage at 14 C which represents the softening of the fruit tissues at the end of the storage period. Keywords- Banana; Modified Atmosphere Storage; Firmness; Texture; PRACTICAL APPLICATION Banana is a rich source of energy, vitamins, minerals which are essential for human nutrition. Being a tropical climacteric fruit, it suffers a lot in terms of post-harvest loss due to its poor shelf life. Hence a study has been undertaken to enhance the shelf-life of two varieties of banana namely Poovan and Robusta using modified atmosphere storage at three different temperatures. The texture of banana plays a major role in determining the ripening qualities which determines the shelf life. The shelf life of Poovan at ambient, 24 and 14 C was 15, 27 and 38 days respectively and for Robusta it was 17, 28 and 38 days respectively. The shelf life of banana could be increased to approximately three to four folds when compared to control (fruits stored in a tray without MA) by adopting this technique. I. INTRODUCTION Banana has a special place in diet with low fat and cholesterol but high in calories. About 1 g of banana provides about 1 calories which is % more energy released by fruits like apples and citrus fruits (Anon, ). Being a tropical climacteric fruit, keeping quality of banana as a whole fruit for long time is not feasible due to its poor shelf life quality. Hence, with growing importance of production of banana products and its preservation, a study was conducted to store banana under modified atmosphere (MA) conditions using diffusion channels. Diffusion channel is a hollow tube or channel fitted in the airtight storage chamber in which produce is stored, and the other end of the tube is exposed to the ambient air. The diffusion channel storage system is one of the methods of modified atmosphere packaging in which the storage chamber is impermeable to gas of concern and the exchange of gas takes place only through the diffusion channels. The presence of diffusion channel controls the flow of gases on either direction (i.e. from package atmosphere to ambient atmosphere and vice versa) thus maintaining the gas composition. Diffusion channel system, works based on the principle of diffusion of gases through the channel due to the concentration gradient of gases between the storage chamber and atmospheric air. Textural properties of the stored fruits serve as an indicator for determination of maturity of the fruits during ripening and senescence. Fruit texture plays a key role for processibilty of the goods to food processor and of eating quality to the consumer. The textural change of softening of the tissue in fruits is caused by enzymatic degradation and solubilisation of pectin materials leading to cell separation and decreased resistance to applied forces (Suresh Nair and Zora Singh, 3). Also, the texture of the stored banana plays a major role in the preparation of processed products like banana figs, powder, jam, chips etc. Hence the present paper deals with the determination of shelf life of banana based on the textural properties during modified atmosphere storage. II. MATERIALS AND METHODS

2 Journal of Agricultural Engineering and Biotechnology May 213, Vol. 1 Iss. 1, PP Two varieties of banana (Musa acuminata), Poovan (AB group) and Robusta (AAA group) were selected for the study. The fresh banana bunches of Poovan and Robusta with 9 percent maturity were procured from farm orchard, Coimbatore, India. The bunches were carefully dehanded and washed in tap water to remove latex, soil particles, floral remains, etc. and shade dried. A. Experimental Containers for Storage Study Poly Ethylene Teraphthalate (PET) containers with 8.5 litres capacity and transparent body were selected for the study. Three holes were made in the lid to fit a silicon septum (for gas sampling), a port for nitrogen flushing and the last one for fixing diffusion channel. All the experimental containers were washed well with soap water and rinsed with chlorinated water ( ppm) and tested for air tightness using soap solution to detect any leaks before starting the experiment. An advantage of this design is that the containers provide quick and easy opening and closing procedures and good visibility to assess the product during the storage period. The experimental setup is shown in the Figure1. B. Experimental Procedure Fig.1 Experimental setup for MA storage of banana The fruits were dipped in ppm of benomyl fungicide for 2-3 minutes (Isaak et al., 6) and then shade dried for about 4-5 hours to facilitate evaporation of surface moisture. This could prevent the fruits from fungal infection during storage. Calcium hydroxide at a rate of 1 g/ kg of fruits used as the CO 2 and moisture absorbent was kept at the bottom of the storage container. A perforated plastic plate was placed above the absorbent (without touching the absorbent) in order to keep the fruit samples so that there was no direct contact between the fruits and the absorbent. Known quantity of fruits were kept over the perforated plastic tray along with the ethylene absorbent(at a rate of 2g/kg fruits)pouch. The containers were then closed with the lids and nitrogen was flushed into the container till the required oxygen concentration of 5 per cent was reached. The containers were then stored in clean and dry place in three different temperatures namely, ambient, 24 C and 14 C. The samples were kept in walk-in cold room to store at 24 C and 14 C by setting the required temperature. The treatment details are mentioned in Table I. The independent variables and its corresponding levels are described in Table II. TABLE I TREATMENT DETAILS FOR BANANA Channel dimensions Channel dimensions Channel dimensions L d L d L d T1 5 3 T5 5 5 T9 5 7 T2 1 3 T6 1 5 T1 1 7 T T T T4 2 3 T8 2 5 T Note: L - length of diffusion channel, cm ; d - inner diameter of diffusion channel, mm TABLE II DESCRIPTION OF INDEPENDENT VARIABLES Sl.No Factors Level Description 1) Variety 2 Poovan, Robusta Ambient (27-33 C, 7 per cent 2) Storage temperature 3 24 C, 9-95 per cent RH and 14 C, 9-95 per cent RH 3) Diffusion channel length 4 5,1,15 and 2 cm 4) Diffusion channel diameter 3 3, 5 and 7mm C. Determination of Firmness in Terms of Penetration Force Cold room

3 Journal of Agricultural Engineering and Biotechnology May 213, Vol. 1 Iss. 1, PP The texture of fruits was determined using the texture analyzer (Stable Micro System, Texture Expert Version 1.22). The texture analyzer is a microprocessor controlled system, which is interfaced to a personal computer. It consisted of two separate modules, the test-bed and the control console (control is done using keyboard). They are linked by a cable through which low voltage signals and power is routed. The texture analyser measures force, distance and time, thus providing three-dimensional product analysis (Figure 2). Forces may be measured to achieve set distances and distances may be measured to achieve set forces. Test for finding the penetration force for set distance was conducted for banana samples of different treatments. The test options and test settings are represented in Table III and Table IV respectively. Fig. 2 Texture Analyser with penetration rig TABLE III TEST OPTIONS FOR TEXTURE ANALYSER Sl.No Test options Command 1 Type of probe used Penetration rig 2 Test module Measure force in compression 3 Test option Return to start TABLE IV TEST SETTINGS FOR TEXTURE ANALYSER Test settings Pre test speed Test speed Post test speed Distance Trigger force Load cell Set values 2. mm/s 1. mm/s 2. mm/s 5 mm 5 g 5 kg Since the fruit peel offered more resistance even at fully ripened stage, the penetration force for flesh of fruits just beneath the peel was recorded by removing a small portion of the peel and the needle was made to penetrate through the flesh. After running the test, the penetration force value was directly obtained from the Personal Computer connected to the texture analyzer. Statistical analysis was carried out to study the effect of different parameters on penetration force. Analysis of variance (ANOVA) was conducted with Factorial Completely Randomized Design (FCRD) using the statistical software AGRES. III. RESULTS The effect of different channel lengths, diameters and storage temperatures on firmness of fruit flesh is presented in Fig.3 and Fig.4 respectively for Poovan and Robusta. From the figures, it is seen that the penetration force decreased with the storage period. The penetration force decreased from 325 g on th day to g on 1 th day and then to 17.8g on 2 th day for T4 in Poovan. The minimum force of g on 1th day decreased to 9.8g on 2 th day for T9 in Poovan under ambient storage. At 24 C, maximum value of 13.4g was noted at 3 th day of storage for T3 and minimum of 8.7g for T5. At 14 C, the maximum and minimum value of 13.3 and 8.2g were noted for T4 and T9 respectively at 4 th day of storage

4 Penetration force (g) Penetration force (g) Penetration force (g) Penetration force (g) Journal of Agricultural Engineering and Biotechnology May 213, Vol. 1 Iss. 1, PP T 1 T 2 T 3 T T 9 T 1 T 11 T 12 Fig. 3 Effect of different on penetration force (g) of Poovan T 1 T 2 T 3 T T 5 T 6 T 7 T 8-2 -

5 Penetration force (g) Journal of Agricultural Engineering and Biotechnology May 213, Vol. 1 Iss. 1, PP T 9 T 1 T 11 T 12 Fig. 4 Effect of different treatments on penetration force (g) of Robusta It is also observed from the Figure3 that all the treatments had higher values of penetration force during initial period of storage representing that the fruits were firm during that period. However, the penetration force drastically decreased on 2 th, 3 th and 4 th day of storage for ambient, 24 and 14 C respectively showing that the fruits became less firm at the end of the storage period. In case of Robusta (Fig.4), the maximum penetration force of 329g on th day decreased to 254.6g on 1 th day and then to 22.3g on 2 th day for T4 and minimum force of 21.2g on 1 th day for T9 decreased to 11.3g on 2 th day under ambient storage. At 24 C, the maximum and minimum penetration force values of 18.7 and 1.8 g were noted for T4 and T9 respectively at 3 th day of storage and also T4 and T9 showed maximum and minimum values of 13.4 g and 9.4g respectively on 4 th day of storage at 14 C. The statistical analysis showed that the treatments and interaction effect on penetration force of Poovan and Robusta were significant at all the three temperatures of storage (Table v). Source data Ambient (Cv-.86%) TABLE V ANALYSIS OF VARIANCE FOR PENETRATION FORCE (FIRMNESS) OF POOVAN AND ROBUSTA Poovan 24 C (Cv-.93%) 14 C (Cv-.95%) Ambient (Cv-.83%) Robusta 24 C (Cv-.91%) 14 C (Cv-.89%) DF F DF F DF F DF F DF F DF F Tot Trt ** ** ** ** ** ** Err s ** ** ** ** ** ** d ** ** ** ** ** ** l ** ** ** ** ** ** s x d ** ** ** ** ** ** d x l ** ** ** ** ** ** s x l ** ** ** ** ** ** s x d x l ** ** ** ** ** ** Tot total ; Trt treatment ; Err- Error ;DF Degrees of Freedom; F F value s - ; d - diffusion channel diameter (mm; l Length of diffusion channel (cm) The fruit samples were in good condition till1 th, 2 th and 3 th day of storage in ambient, 24 C and 14 C storage respectively. Beyond this storage period, the samples were observed daily and compared with control fruits and safe storage period was determined and the data were represented in Table VI. TABLE VI BEST TREATMENT FOR BANANA AT DIFFERENT STORAGE TEMPERATURES Variety Poovan Robusta Temperature Fruits under diffusion channel storage Best Shelf life (days) Control Shelf life (days) Ambient T C T C T Ambient T C T C T

6 Journal of Agricultural Engineering and Biotechnology May 213, Vol. 1 Iss. 1, PP IV. DISCUSSION It is obvious that for most of the cases, penetration force for the treatments with smallest diameter and largest length of channel were higher compared to largest diameter and smallest length. The reduction in firmness of banana fruits was observed by Charles and Tung (1973), Chen and Ramasamy (2) during storage. The area and length of passage might have influenced the movement of oxygen into the chamber which in turn influences the ripening behavior of the fruits. The loss of firmness during ripening has been linked to three major factors :(1) breakdown of starch into sugars :(2) the breakdown of cell walls or reduction in cohesion of the middle lamella due to solubulization of pectic substances: and (3) migration of water from skin to flesh due to osmosis (Palmer, 1971; Smith et al.,1989). It is inferred from the Table VI that the shelf life of Poovan and Robusta can be increased to three to four folds by adopting diffusion channel technique compared to control fruits at all the respective storage temperatures. REFERENCES [1] Anon. International network for improvement of banana and plantain. Annual report.a. Montpellier (FRA), p [2] R.J Charles and M.A Tung. Physical, rheological and chemical properties of bananas during ripening. Journal of Food Science. 38: [3] C.R Chen and R.H.S Ramaswamy. Color and texture change kinetics in ripening bananas. Labensm-WISS-U-Technology. 35: [4] G.P Isaak, V.B Kudachikar, S.G Kulkarni, M.S Vasantha, M.N.K Prakash and K.V.R Ramana. 6. Shelf-life quality of modified atmosphered packed plantains during low temperature storage. Journal of Food Science and Technology. 43(6): [5] A.V.D Kasteele. The banana chain. The macro economics of the banana trade. International Banana conference, Brussels May [6] S.Nair and Z. Singh. Pre-storage ethrel dip reduces chilling injury, enhances respiration rate, ethylene production and improves fruit quality of Kensingron mango. Food, Agriculture and Environment.2: [7] K.K Palmer. The Banana. In: Biochemistry of fruits and their products (edited by A.C.Hulme).Academic Press, New York.1971 [8] N.J.S Smith, G.A Tucker and J. Jeger. Softening and cell wall changes in bananas and plantains. Aspects of Applied Biology. 2,