Shelf Life Extention Of Banana

SHELF LIFE EXTENSION OF BANANA BY GAMMA RADIATION AS A SUBSTITUTE OF CHEMICAL FUMIGATION W. Zaman , Dipak Kumar Paul, M. Khorshed Alam1 and M.Masihul Alam.

Department of applied Nutrition and Food Technology, Islamic University, Kushtia, Bangladesh. 1 IFRB, Bangladesh Atomic Energy Research Establishment, Savar, Dhaka.

ABSTRACT Effect of Gamma radiation on the shelf life extension of Bananas was investigated. The Bananas were treated with radiation of three doses 0.30kGy; 0.40kGy and 0.50kGy followed the storage at room temperature. The physical conditions of the treated and untreated Bananas were analyzed every 2 days intervals for their organoleptic properties till spoilage at room temperature in comparison to control. The chemical analyses of the treated and untreated Bananas were carried out quantitatively at intervals of 2-4 days at room temperature through out the storage period. A taste-testing panel of 16 panelists found out the acceptability of the fruit. The score given by the panelists for different attributes of the fruits were statistically analyzed to find out the acceptability of the fruit. The fruits treated with the three radiation doses contain 72.7%-75.7% Moisture, 2-22gm Carbohydrates, less than 1- 20gm Soluble sugar, 0.84-1.2gm Fibre, 0.5-0.7gm Pectin, 1.1-1.3gm Protein, 0.10-0.3gmFat, 0.8-1.4gm Ash, 10-26mg Ascorbic acid and 0.003-0. 001mg Beta-carotene per 100gm respectively and were found acceptable till 21-26 days at room temperature whereas in the case of control the fruits stored at room temperature spoiled within 3-6 days. Thus radiation can be the safe way for the shelf life extension of Bananas instead of chemical fumigation which is very much health hazardous. INTRODUCTION Banana has been an important cultivated fruits from time immemorial and by far the most important tropical fruits (Farooqi et al., 1987)

[1]

. This is one of the superiors and largest

cultivated fruits of Bangladesh (Ahmed et al., 1998) [2]. The edible Banana is indigenous to the warm moist parts of Asia. It is not only the staple food of millions of people, but is also the most important commercial fruit of the tropical areas of the world(Gottreich et al., 1969) [3]. In Bangladesh, Banana is a popular and economical fruit, which constitutes 42% of fruits(Mitra,1969)

[4]

. The important of this fruits is due to its high calories and

nutritive value and of its versatile use to the consumers. It contains appreciable amount of vitamin B and certain amount of vitamin A & C and also minerals, such as K, P, Ca, Fe, Na etc (Southgate, 1969) powder,

jam

[5]

. Various products like banana chips, banana figs, flour,

confectionery,

banana(Ronald,1984)

[6]

dehydrated

slice

etc.

can

be

prepared

from

. Banana is a perishable food items and cannot be preserved for

longer time after harvesting. In relation to food, we have two major problems in Bangladesh. One is the food deficit and other is the post-harvest loss. The farmers could be encouraged for more production if spoilage could be prevented by proper preservation, which could result in increased and balanced consumption. Moreover, substantial amount of foreign exchange could be earned by exporting the fresh and processed

products

(Vendrell et al.,1971) [7].From the prevailing condition it seems that the lack of suitable preservation methods is a major factor contributing to the primary limitation to production and consumption of increased amount of the fruit. In developing countries, the processing and preservation of food have taken the form of commercial food industries where sophisticated techniques and equipment are being employed. But at present, there is dearth skilled manpower, machineries and capital to establish modern processing industries in Bangladesh (Spalding et al.,1988) [8]. In view of the above-mentioned limitations and the prevailing socio-economic conditions, we have to start from low cost labor-intensive technologies for food preservation in a small scale at the first instance and then gradually shift towards large-scale industrialization. Thus developing a processed product in Bangladesh should not involve major changes in habits(Quinn, 1967) [9]. Post harvest fruits losses due to insect infection are a serious, costly and worldwide problem. Ethylene Dibromide (EDB), one of the most effective and widely used fumigant for fruits and vegetables, has been highly controversial in recent years. The Environmental Protection Agency (EPA) subsequently banned the EDB in the USA in September 1984 as a fumigant for fruits and vegetables and soil (Maxie,1971)

[10]

.

Ethylene Dibromide (EDB), which has been used as an effective fumigant for fruit for over 40 years in the USA. EDB became a controversy in the mid-1970’s when a National Cancer Institute (NCI, USA) study showed the chemical to be cancer-causing agent in experimental animals (Stover, 1970) [11].

When an effective fumigant is banned, it creates the problem of finding an alternative or substitute that can do the same job or better. Ionizing radiation in the form of Gammaradiation or high-energy electrons has been studied for over 30 years around the world as a food preservation technique. It is potentially feasible substitute for chemical fumigation of fruits and vegetables. The advantages of irradiation over chemical fumigation for decontamination and disinfestations are briefly explained in view of the fact that irradiation could become the most effective substitute for chemical fumigants. The use of low dose radiation for insect disinfestations is emerging as a possible substitute for chemical fumigation because of recent events and controversies over chemicals and pesticides in foods (Siddapa,1951) [12]. For delay ripening fruits by irradiation, a very comprehensive review was prepared by Loaharanu (Ayyad et al., 1990)

[13]

. As of August 1985, 30 countries including

Bangladesh around the world have cleared more than 40 irradiated food item for human consumption on either an unconditional or provisional basis for various purposes (Koszler,1959)

[14]

. The US FDA has recently (March, 1986) announced the approval in

principle of irradiated fruits up to 1.0 kGy for delay ripening and disinfestations (Grecz,1983) [15]. This study will minimize post harvest losses of the fruit. Thus growers will be economically benefited and encouraged to grow more foods. The successful value added food production will encourage the food processors to build up processing plant and their ensured shelf life will increase the export of value added food products. Thus the surplus Bananas will be utilized and saved from spoilage. The radiated pulp and pulp-based products may play an important role to our national economy through formation of new employment opportunity of our rural manpower. With this view in mind the following objective will be tried to achieve for solution of the project.

METHODS AND MATERIALS Collection of Banana and sample preparation: For this study mature green Bananas (Musa sapientum) of medium sizes were collected from different local markets of Savar, Dhaka, Bangladesh. Following collection, the Bananas were cleaned and washed with tape water. The prepared bananas were poured into plastic bag and sealed tightly. The sealed plastic bags were labeled by indicating the name of the product and the doses those will have to apply. Radiation: Bananas were treated with different doses of Gamma radiation and stored at room temperature. The sealed plastic bags were labeled by indicating the name of the product applied doses (Control 0.0 kGy, 0.3kGy, 0.4kGy and 0.5kGy). Radiation was given in the filled bag by using Co-60 source of radiation. The final products were stored in dry place at room temperature and observed shelf life of the bananas. Techniques used: Shelf life was estimated by the data obtained in response of organoleptic test and chemical analysis. Quality attributes were evaluated just after radiation and at 26 days storage. Organoleptic test and Chemical composition were done at an interval of 2-4 days respectively throughout the storage period. Samples of each lot were chemically analyzed to find their proximate value. The moisture content was determined by weight loss of the sample on drying at 105ºC for 6 h (AOAC,1984) [16].Ash content was determined through Straight Combustion Method by Triebold and Aurand (Triebold et al.,1969) [17] .Crude fiber content was determined by the method of ICMR (ICMR, 1971)[18].Lipid was determined by AOAC official method 922.06(AOAC, 1995)[19].Using Nx6.25 calculated protein content from total nitrogen after determination of the total nitrogen by micro Kjeldahl Method (AOAC, 1995) [19].Carbohydrate content was determined by subtracting the sum of the total value /100g for moisture, ash, protein, fat and crude fiber from 100 according to Anonymous (Anonymous,1971)

[20]

.Ascorbic

acid (Vitamin-C) content was estimated by 2,4-dinitro-phenylhydrazine method (Roe et al.,1969)

[21]

. β-carotene was estimated by method of Holden (Holden,1981)

[22]

. Total

titrable acidity, pectin content reducing sugar, calcium, phosphorous and iron content were determined by standard methods (Ranganna, 1980) [23].

Sensory evaluation: Sensory evaluations of all formulated Bananas were done by tastetesting panel. This taste-testing panel was carried out by 16 panelists. They were asked to evaluate color, flavor and overall acceptability a scoring rate on a 9-point hedonic scale. Where, 9 = Excellent, 8 = very good, 6 = acceptable and 4 = poor. The preference differences were evaluated by statistical analysis of the data for variance.

RESULTS The analyzed chemical compositions immediate after harvesting and after radiation are represented in Table 1. Table 1: Comparison of observed Chemical composition of Banana just after harvesting (before radiation) and after radiation per 100gm. Constituents of Banana

After harvesting

After radiation

Moisture content Ash content(gm) pH Vitamin-C(mg) Reducing sugar(gm) Carbohydrates(gm) Crude fat(gm) Protein(gm) Fibre(gm) Pectin(gm)

72.8% 0.8 4.2 24 mg 2.6 21.0 0.25 1.3 0.82 0.50

72.7-75.7% 0.8-1.38 4.2-5.2 10-24 mg 2.6-18.0 2-18 0.1-0.25 1.1-1.3 0.80-1.6 0.5-0.70

The moisture content of all the stored Banana was found within the range of 72.7-75.7%. It was observed that there were no remarkable changes in the moisture content through the storage period. Ash content of the samples varies from 0.8-1.4gm per 100gm. Throughout the storage period, there were no remarkable changes in ash content of different samples. The value of PH varies 4.2 to 5.3 of the sample for different storage time. Slight variation of PH was observed throughout storage period. The variation of PH was due to variation of acidity occurred during storage period at room temperature. The ascorbic acid of different treated Banana was determined at every 2-4 days interval. The loss of ascorbic acid is dependent on temperature and storage time. In general the losses in vitamin-C content rarely exceed 20 to 30%. The irradiation of bananas at doses below 1 kGy may cause only minor and insignificant chemical changes and very little loss of vitamin-C content occurs and it is not nutritionally significant shown in Table-2 and Figure 1.

Table: 2 Effect of Gamma radiation on Ascorbic acid content (mg/100gm) of the Banana stored at room temperature Storage period

Control (Cn)

Radiation

Radiation

Radiation

(days) 0 2 4 6 8 12 16 20 24 26

0.0kGy 24 22 20 18 nd nd nd nd nd nd

0.3kGy 20 18 17 17 16 15 14 13 13 13

0.4kGy 18 17 17 16 16 14 13 12 12 12

0.5kGy 17 16 16 16 15 13 12 11 11 10

* nd = not done as spoiled

30

Control

25

Radiation 0.3kGy Radiation 0.4kGy Radiation 0.5kGy

20 15 10 5

ys

da

ys 26

da

ys 24

da

ys 20

da

ys 16

12

da

ys

da

ys 8

da

ys 6

da

da

4

2

da 0

y

0

y

ascorbic acis content (mg/100gm)

Effect of Gamma Radiation on ascorbic acid content (mg/100gm) of the Banana stored at room temperature

Storage Period

Figure-1: Effect of Gamma radiation on the Ascorbic acid content (mg/100gm) n of the Banana stored at room temperature

The carbohydrate contents decreased due to inversion of sugar in presence of acid during storage. During the storage period the carbohydrate content of the control was gradually decreased. On the other hand the radiated samples were showed slowly decrease with increasing storage period because of radiation represented in Table-3 and Figure-2. Table: 3 Effect of Gamma radiation on total carbohydrate content (gm/100gm) of the Banana stored at room temperature Storage period

Control (Cn)

(days) 0.0kGy 0 24 2 22 4 20 6 18 8 nd 12 nd 16 nd 20 nd 24 nd 26 nd * nd = not done as spoiled

Radiation

Radiation

Radiation

0.3kGy 20 18 17 17 16 15 14 13 13 13

0.4kGy 18 17 17 16 16 14 13 12 12 12

0.5kGy 17 16 16 16 15 13 12 11 11 10

20 18 16 14 12 10 8 6 4 2 0

Control Radiation 0.3kGy Radiation 0.4kGy

da 2 y d 4 ay da 6 ys da 8 ys d 12 ays d 16 ays d 20 ays d 24 ays d 26 ays da ys

Radiation 0.5kGy

0

total carbohydrate content gm/100gm

Effect of Gamma Radiation on total carbohydrate content of the Banana stored at room temperature

Storage Period

Figure-2: Effect of Gamma radiation on total carbohydrate content (gm/100gm)

of the

Banana stored at room temperature

The reducing sugar contents increased due to inversion of sugar during storage period. But in radiated it is opposite figure, sugar percentage increases slowly after radiation. During the storage period the reducing sugar content of the control was gradually increased. On the other hand the radiated samples were showed slowly increase of reducing sugar after radiation represented in Table-4 and Figure-3. Table: 4 Effect of Gamma radiation on reducing sugar content (gm/100gm) of the Banana stored at room temperature Storage period

Control (Cn)

Radiation

Radiation

Radiation

(days) 0 2

0.0kGy 2.6 6.8

0.3kGy 2.5 2.9

0.4kGy 2.4 2.8

0.5kGy 2.3 2.3

4 11.7 6 14.4 8 nd 12 nd 16 nd 20 nd 24 nd 26 nd * nd = not done as spoiled

3.6 7.4 8.2 10.7 13.4 14.9 16.2 18.0

3.2 6.9 7.5 9.2 11.7 13.6 15.9 16.4

3.0 5.3 6.3 8.0 10.3 11.3 13.8 14.7

20 18 16 14 12 10 8 6 4 2 0

Control Radiation 0.3kGy

da ys

Radiation 0.5kGy

24

da ys

16

da ys

8

4

0

da ys

Radiation 0.4kGy

da y

reducing sugar content gm/100gm

Effect of Gamma Radiation on reducing sugar content of the Banana stored at room temperature

Storage Period

Figure-3: Effect of Gamma radiation on reducing content (gm/100gm) of the Banana stored at room temperature.

The crude fibre content of the Banana were determined every 2-4 days interval of storage period of the sample. The fibre after radiation was about 0.84-1.2gm per 100gm during storage. It was observed that there were no remarkable changes in crude fibre throughout the

storage .The crude fat content of the pulp was comparatively too minimum. It was determined every 2-4 days interval of storage period of the samples. The fat varies 0.1 to 0.3gm per 100gm during storage. It was observed that there were no remarkable changes in crude fibre during the storage period. Throughout the storage period the slight variation of protein content was observed at room temperature. The protein content varies 1.1-1.3 gm per 100gm during storage. It was observed that there were no remarkable changes in protein content throughout the storage period. Throughout the storage period the slight variation of pectin content was observed at room temperature. The pectin content varies 0.5-0.7 gm per 100gm during storage. It was observed that there were no remarkable changes in pectin content throughout the storage period [26]. Throughout the storage period the slight variation of beta-carotene content was observed at room temperature. The content beta-carotene varies 0.003-0.001gm per 100gm during storage. It was observed that there

were

no

remarkable

changes

in

beta-carotene

content

throughout the storage period. Throughout the storage period the slight variation of calcium content was observed at room temperature. The Calcium content varies 8.012.0mg/100gm during storage. It was observed that there were no remarkable changes in Calcium content throughout the storage period. Throughout the storage period the slight variation of Phosphorus content was observed at room temperature. The phosphorus content varies 18-22mg/100gm during storage. It was observed that there were no remarkable changes in Phosphorus content throughout the storage period. Throughout the storage period the slight variation of Iron content was observed at room temperature. The Iron content varies 0.6-0.8 during storage. It was observed that there were no remarkable changes in Iron content throughout the storage period.

The sample of different doses was observed continuously to see the shelf life extension of the Banana stored at room temperature and the results are given in Table 5 and Figure 4.

Table 5: Effect of Gamma radiation on the shelf life extension of the Banana stored at room temperature % Of the Sample of ripening Storage

Control (Cn)

Radiation

Radiation

Radiation

period

0.0kGy

0.3kGy

0.4kGy

0.5kGy

0 24 87 100 nd nd nd nd nd nd nd nd nd nd nd nd

0 0 5 8 10 12 16 20 25 32 40 65 73 85 100 100

0 0 0 3 7 8 11 14 18 24 30 54 62 76 92 100

0 0 0 1 4 5 8 12 15 21 27 39 57 69 85 95

nd

100

100

100

(days)

0 2 4 6 8 10 12 14 16 18 20 22 24 24 26 27 28 •

nd = not done as spoiled

Effect of Gamma Radiation on the shelf life extension of the Banana stored at room temperature 120

% of ripening

100

Control

80

Radiation 0.3kGy

60

Radiation 0.4kGy

40

Radiation 0.5kGy

20

da ys

28

da ys

26

da ys

20

da ys

12

da ys

6

4

da ys

da y 2

0

da y

0

Storage Period Figure-4: Effect of Gamma radiation on the shelf life extension of the Banana stored at room temperature

The irradiated bananas were subjected to sensory evaluation just after radiation and 26 days of storage at room temperature. A panel of 16 judges evaluated the flavor, color and overall acceptability of the stored Banana. The mean scores for color, flavor and overall acceptability of different treated Banana are presented in Table 6. The scores given by the panelists were analyzed for each quality attributes. A statistical analysis of the score response by the taste-testing panelists on the Banana revealed that color, flavor and overall acceptability were not significantly different due to the treatment. Control Bananas stored at room temperature were spoiled within 6 days

whereas the shelf life of the irradiated Bananas could extend up to 26 days of storage at room temperature. It was found that the Banana with 0.3kGy Gamma radiation were higher acceptable by the taste-testing panelists. A two-way analysis of variance indicated that all the sensory attributes of different radiated Bananas were not significantly (P<0.05) different and thus the sensory attributes of the Banana showed equally acceptable (Gross, 1976) [24 Table 6: Rating scores for overall acceptability of the Banana after 26days storage. No of taster 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Total Mean

Sample Control 7 6 5 6 5 6 6 7 8 5 6 6 6 7 6 7 99 6.187

1kGy 6 5 6 6 7 6 5 7 6 5 7 6 4 6 5 8 95 5.937

3kGy 7 8 7 6 7 6 7 8 8 7 7 8 8 7 9 8 118 7.375

5kGy 7 7 8 7 6 8 6 7 8 7 6 6 6 7 6 7 109 6.812

Hedonic scale: Excellent=9; Very good=8; Good=7; Acceptable=6; Poor=5. DISCUSSION The objectives of the present study are to extend the shelf life of Bananas using Gamma radiation at room temperature. During storage negligible changes were observed in moisture, ash and fiber content. Slightly change occurred in case of acidity, p H, and Protein content. No remarkable decrease of ascorbic acid was observed. In case reducing

sugar gradual increase was observed after radiation with storage period whereas in control sudden increase of reducing sugar was observed with storage period. The feasibility of applying ionizing radiation technique depends on a fruit’s tolerance to a minimum dose. At the joint FAO/IAEA panel meeting on irradiation to solve Quarantine problems in the International Fruit Trade, December, 1970, several researchers presented result of their studies on irradiated fruits such as Banana, Apples, Mango etc. which showed that all of these fruits could tolerate Gamma-radiation treatment to 1.0 kGy without any phytotoxicity (Marriott,1980).[25] More recent studies on the use of Gammaradiation as a substitute of chemical fumigation showed that the fruits could tolerate 0.5 kGy treatment without any external or internal chemical or sensory quality changes(Marriott,1980; Salda et al.,1976; Kenyhercz et al.,1978

[25,26,27]

. Fruits could

actually tolerate up to 0.75 kGy without any quality changes especially refrigerated at 70C (Kesevan et al., 1966) [28]. In this study acceptability of the stored pulp was tested by a panel of 16 judges. It was found that the Banana with 0.3kGy Gamma radiation were higher acceptable by the tastetesting panelists. With the result of the research it will be helpful to identify the Physical, Chemical and nutrients content of Banana, to study the shelf-life of irradiated Bananas, to identify the nutritional condition during preservation of irradiated Bananas, to compare the nutritional quality and quantity of irradiated and chemically fumigants Bananas, to reduce the losses of post-harvested Bananas, to extend commercial uses of Bananas.

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E.C.

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of

irradiating

fresh

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and

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Mycosphae-rella musicola and itspossaiublerole in premature ripening of the fruit. Phytopathology (Abstr.) . 60, 1542. [12.]

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Ayyad, K., Hassanien. F., Ragab. M.,(1990). The effect of gamma irradiation on

the structure of pectin. Zagazig University, Zagazig , Egypt. [14] Koszler, V. (1959) Bananas for infantile diarrohea. Neue Oesterr. Z. Kinderheilkd., 4, 212-14 (in German). [15.] Grecz, N. 1983. Action of radiation on bacteria and viruses. In: Preservation of Food by Ionizing Radiation vol.II. (Eds. Josephson.) CRC Press Inc., Boca Raton , Florida, p.179. [16.] Official method of analysis, 1984.(Williams S. Eds.).14th ed. Association of official Analytical Chemist. Inc. Verginia.

[17] Triebold, H.O. and L.W. Aurand, 1969. Food Composition and Analysis. Van Nostrand Reinhold Co. New York, U.S. 2 Ed. 31. [18]

Indian Council for Medical Research(ICMR),1971.A Manual of Laboratory

Techniques, National Institute of Nutrition, Hyderabad, India, pp:2-6. [19] Association of Official Analytical Chemist(AOAC),1995. Official Methods of Analysis, 16th Ed. (Williams S. Eds.). [20] Anonymous, 1971. A manual of Laboratory Techniques, National Institute of Nutrition, Hyderabad, India, pp:2-7. [21] Roe, J.H. and M.J. Asterlin, 1969. The Determination of Dehydro Ascorbic Acid and Ascorbic acid in plant Tissue by the 2,4-dinitro-phenylhydrazine method. J. Biol. Chem., 152:511-513. [22] Holden, M. A., 1981. A rapid and simple method for determining carotene in plant materials , Xaropthalmia Club, U.K. Bulletin no. 22. [23] Analysis of Fruits and Vegetable by S. Ranganna(1980). [24] . Gross, J. (1976) Carotenoids of banana pulp, peel and leaves. Lebensm. Wiss. Technol., 9, 211-14.Banana,third edition(1984) R.H. stover. [25] Marriott, J. (1980) Bananas: physiology and biochemistry of storage and ripening for optimum quality. Crit. Rev. Food Sci. Nutr., 13, 41-88. [26] Salda, G., Stephers, T.S., Lim, B.J. (1976) Carrot Beverage Journal of Food Science. 41 (5): 12543-1244. [27.] Kenyhercz, T.M. and Kissinger, P. T. (1978) Identification and quantitation of tryptophan and tyrosine metabolites in banana by liquid chromatography with electrochemical detection . J. Food Sci., 43, 1354-6. [28] Kesevan, P.C. et al. 1966. Cytotoxic etc. human leukocytes. Current Science 35: 403-404.