QUEIROZ, M. R. de

RESENDE, J. M.

SAGGIN JUNIOR, O. J.

SILVA, O. F.

SOARES, A. G.

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Microbiological quality of water of green coconut with different coatings.

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Proceedings of the 6th CIGR Section VI International Symposium “Towards a Sustainable Food Chain” Food Process, Bioprocessing and Food Quality Management  Nantes, France - April 18-20, 2011  Microbiological Quality of Water of Green Coconut With Different Coatings Josane Maria Resende1, Marlene Rita de Queiroz2*, Antônio Gomes Soares3, Otniel Freitas Silva3, Orivaldo José Saggin Júnior4 1 Institute of Technology, Federal Rural University of Rio de Janeiro – UFRRJ, BR 465, km 7, Seropédica, 23890000, RJ, Brazil 2 School of Agriculture Engineering, University of Campinas – Unicamp, Campinas, 13083-875, SP, Brazil, phone (55) 19-35211073, fax (55) 19-35211005, marlene@agr.unicamp.br 3 Brazilian Agricultural Research Corporation – Embrapa Food Agoindustry, PO 20501, Rio de Janeiro, 23020470, RJ, Brazil 4 Brazilian Agricultural Research Corporation – Embrapa Agrobiology, PO 74505, BR 465, km 7, Seropédica 23890000, RJ, Brazil Written for presentation at the 2011 CIGR Section VI International Symposium on    Towards a Sustainable Food Chain Food Process, Bioprocessing and Food Quality Management  Nantes, France - April 18-20, 2011  Abstract. The objective of this work was to evaluate the effect of different biodegradable coatings on the microbiological quality of coconut water 'Anão Verde' variety stored for 40 days. The presence of coliforms at 45 ºC and 35 ºC, mesophilic aerobics, filamentous fungi and yeasts in the water was lower in fruit coated with chitosan and chitosan + gelatin. The contamination was higher in the water of fruits coated with gelatin and in the control fruits (no coating). Throughout storage time, only three genera of fungi were identified in coconut water: Penicillium, Fusarium and Paelomyces. The genus Penicillium was found more frequently in relation to Fusarium and the latest in relation to Paelomyces. During the storage, the waters of the fruits coated with gelatin, gelatin + carboxymethylcellulose and the control fruits presented higher frequency of contamination with these fungi, while the waters of fruit coated with chitosan and chitosan + gelatin had a lower frequency. The fruit coated with chitosan and chitosan + gelatin better preserved the microbiological quality of the coconut water for natural consumption in the own fruit.  Keywords. Cocos nucifera, storage, fungi, bacteria, chitosan, gelatin  2 Introducão Coconut water is a refreshing and tasty drink, very popular in Brazil and other tropical countries. It consists mainly of sugars and minerals, nitrogenous substances and vitamins, wich characterizes a product of easy contamination and rapid deterioration in contact with the environment. The chemistry sanitization of the coconut surface is limited due to the husk irregularities and to the calyx and stalk structures that facilitate microbial attachment. The application of biodegradable coatings has been focused to control the development of microorganisms and to increase the shelf life of products. Several authors mention the antimicrobial activity of chitosan to inhibit the growth of microorganisms, among them, Fusarium sp (Ravi Kumar, 2000). The objetive of this study was to evaluate the effect of different biodegradable coatings on the microbiological quality of coconut water during storage for 40 days. Material & Methods Coconut (Cocos nucifera L.), ‘Anão Verde’ variety with eight months of age was used. After cleaning, sorting and sanitizing, the fruits were separated into portions to applied the coatings (Table 1) through immersion for 1 minute and then they were dried at room temperature. Table 1. Treatments and respective formulations used to coat the coconuts Treatment Formulations 1 Chitosan 1.5 % + glycerol (20% v/p chitosan) + PEG-400 (10% v/p chitosan) 2 Carboxymethilcellulose (CMC) 3% + gelatin 5% 3 Chitosan 1.5% + gelatin 5% 4 CMC 3% + stearic acid (15% p/p CMC) + PEG-400 (10% v/p CMC) 5 Gelatin 5% + glycerol (15% v/p gelatin) + PEG-400 (10% v/p gelatin) 6 Control (pure water) After that the fruits were stored at 12 ± 2 ºC, 80% RH for 40 days. The experimental unit was composed of two fruits. The following microbiological analysis of water were done every 10 days: total coliforms (35 ºC) and fecal coliforms (45 ºC); counting of mesophilic aerobics, filamentous fungi and yeasts; identification of filamentous fungi. The analysis followed the methodology proposed by Vanderzant & Splittstoesser (1992), modified by Smith (1995), and Downes & Ito (2001). The analysis of filamentous fungi was based on methodology described by Pitt & Hocking (1997) and Samson et al. (2004) for isolation and identification, respectively. A completely randomized design with split plot in time was used and the interaction between the factors time and coatings was investigated. The results were submitted to analysis of variance and the Scott Knott 5% average test. Results e Discussion A significant interaction between the coatings and the storage time in all microbiological evaluations was observed, except for filamentous fungi and yeasts that showed isolated effect of coatings and storage time (Table 1).    3 Table 1. Anlysis of Variance  Sources of variation Variable Coatings Time Coatings x time Coliforms 35 °C 0.00 ** 0.00 ** 0.00 ** Coliforms 45 °C 0.00 ** 0.00 ** 0.00 ** Mesophilic Aerobics  0.02 * 0.00 ** 0.02 * Filamentous fungi and yeasts 0.01 ** 0.01 ** 0.61 *: F significative (p=0.02); **: F significative (p<0.01) At 40 days of storage, there was no presence of coliform at 45 °C in water for fruit coated with chitosan, gelatin + CMC and chitosan + gelatin (Table 2). Table 2. Most probable number (MPN) of propagules of coliforms at 45 ºC and coliforms at 35 °C and counting of mesophilic aerobic bacteria, filamentous fungi and yeasts in coconut water using different coatings for 40 days of storage at 12 ° C  Coatings Days Coli 45 ºC (MPN mL-1) Coli 35 ºC (MPN mL-1) Mesophilic Aerobics  (CFU mL-1) Filamentous and Yeasts (CFU mL-1) Chitosan 0 ND ND 2.0x101 1 Gelatin + CMC 0 ND 5 5.1x101 3 Chitosan + gelatin 0 ND ND 3.9 x101 2 CMC 0 ND 4 5.4 x101 5 Gelatin 0 ND ND 1.32 x102 7 Control 0 ND ND 1.02 x102 2.4 x 101 Chitosan 10 ND ND 2.8 x101 5 Gelatin + CMC 10 ND ND 1.81 x102 6 Chitosan + gelatin 10 ND ND 6.9 x 101 5 CMC 10 ND ND 3.30 x102 3.9 x 101 Gelatin 10 ND ND 1.71 x102 1.88 x 102 Control 10 ND ND 7.66 x102 6.52 x 102 Chitosan 20 ND ND 1.2 x 101 6 Gelatin + CMC 20 ND ND 3.3 x 101 1.0 x 101 Chitosan + gelatin 20 ND ND 1.1 x 101 8 CMC 20 ND ND 4.5 x 101 1.1 x 101 Gelatin 20 ND ND 2.5 x 101 5.4 x 101 Control 20 ND ND 1.86 x102 8.5 x 101 Chitosan 30 ND ND 3.53 x102 4.8 x 101 Gelatin + CMC 30 ND 9 4.71 x102 2.83 x102 Chitosan + gelatin 30 ND ND 3.69 x102 6.8 x 101 CMC 30 4 7 4.10 x102 6.5 x 101 Gelatin 30 4 11 4.80 x102 2.09 x102 Control 30 9 26 8.92 x102 3.67 x102 Chitosan 40 ND ND 3.93 x102 5.3 x 101 Gelatin + CMC 40 ND 11 1.053 x 103 1.02 x102 Chitosan + gelatin 40 ND 16 7.03 x102 9.2 x 101 CMC 40 ND 7 2.040 x 103 4.80 x102 Gelatin 40 11 15 1.487 x 103 3.37 x102 Control 40 4 9 1.1767 x 104 8.48 x102 At 30 days of storage coliforms at 35 ºC were not observed in the treatments with chitosan and chitosan + gelatin and also in all the treatment with chitosan at 40 days of storage(Table 2).  4 These data indicate that chitosan coatings can be effective to reduce the infestation of coliforms during storage and can help to keep away these microorganisms in the water of fruit stored until 40 days. The number (CFU) of mesophilic aerobic bacteria, filamentous fungi and yeasts (Table 2) increased during the storage. The lower number of CFU of aerobic mesophilics was observed in the water from the fruit treated with chitosan and chitosan + gelatin throughout the storage period. During storage only three genera of fungi in coconut water were identified in this order of frequency: Penicillium, Fusarium and Paelomyces. Fungi were not identified at the beginning of storage. At 10 days the first contaminations arised and increased until the end of storage. During storage, the water from fruits treated with chitosan and chitosan + gelatin had lower rates of contamination. The highest frequency of fungi (Penicillium and Fusarium) on water from fruits coated with gelatin suggests that gelatin facilitates the infestation of these fungi. Gelatin is an animal protein containing the essential amino acids, except tryptophan, which may have favored the faster growth of fungi. The lower frequency of fungi on water from coconuts treated with chitosan and chitosan + gelatin shows the effect of antimicrobial properties of chitosan on growth of Penicillium and Fusarium. Conclusions Coconut coated with chitosan and chitosan + gelatin better preserved the microbiological quality of coconut water for natural consumption in the own fruit, indicating the antimicrobial propertie of chitosan. The main fungi identified in the coconut water during storage were Penicillium, Fusarium and Paelomyces, in that order of frequency. Referências Aguila, J.S., Sasaki, F.F., Heiffig, L.S., Ongarelli, M.G., Gallo C.R., Jacomino, A.P., & Kluge, R.A. 2006. Determinação da microflora em rabanetes minimamente processados. Horticultura Brasileira, 24: 75-78.  Downes, F. P. & ITO, K. (ed.) 2001. Compendium of methods for the microbiological examination of foods. 4th ed. Washington, DC: APHA-American Public Health Association, 676p. Pitt, J. I. & Hocking, A. D. 1997. Fungi and food spoilage. 2nd ed. London, UK: Springer.  Ravi Kumar, M.N.V. 2000. A review of chitin and chitosan applications. Reactive and Functional Polymers 46(1): 1-27.  Samson, R. A., Hoekstra, E. S., & Frisvad, J. C. 2004. Introduction to Food- and airborne Fungi. 7th ed. Baarn: CBS. 389 p. Disponível em: http://www.cbs.knaw.nl. Acesso em: 10 dez. 2006. Siqueira, R.S. Manual de microbiologia de alimentos. 1995. Brasília: EMBRAPA-SPI; Rio de Janeiro: Embrapa-CTAA.  Vanderzant, C. & Splittstoesser, D.F. 1992. Compendium of methods for the microbiological examination of foods. 3rd ed., Washington: Americam Public Health Association. 

Microbiological quality of water of green coconut with different coatings.

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