Risalah Seminar Nasional Pengawetan Makanan Dengan Iradiasi, Jakarta, 6 - 8 Juni 1983
QUALITY CHANGES OF IRRADIATED RIO US PACKAGING MATERIALS
SPICES STORED
IN VA-
T.S. Saputra *, M. Maha *, Z.I. Purwanto * ABSTRAK
- ABSTRACT
Perubahan mutu rempah-rempah iradiasi yang disimpan dalam berbagai pengemas tertentu. Telah dilakukan pemeriksaan mutu rempah-rempah iradiasi yaitu biji pala (Myristica fragrans), lada hitam dan lada putih (Piper nigrum) yang disimpan dalam berbagai pengemas tertentu. Pengemas yang dipergunakan ialah kaleng, kaleng yang bagian dalamnya dilapisi film polipropilen, kaleng yang bagian dalamnya dilapisi kertas merang, karung plastik polipropilen dan karung plastik polipropilen yang bagian dalamnya dilapisi film polipropilen. Hasil penelitian menunjukkan bahwa dengan karung plastik polipropilen dapat menyebabkan perubahan nyata pada kadar air dan aktivitas air sedang pengemasan dengan kaleng tidak memberikan perubahan selama penyimpanan. Dengan menggunakan lapisan film polipropilen pada bagian dalam karung plastik, perubahan-perubahan tersebut dapat dihambat. Angka total mikroba, angka total kapang dan khamir, dan nilai organoleptik rempah-rempah tidak dipengaruhi oleh cara pengemasan. Dosis 5 kGy dapat mengurangi kandungan mikroba rempah-rempah sebanyak 2 - 3 "log cycles". Penyimpanan dalam waktu lama menyebabkan perubahan sifat-sifat organoleptik rempah-rempah, selain itu juga menurunkan kandungan mikroba pada biji pala dan lada hitam. Pada lada putih, penyimpanan sedikit menaikkan kandungan mikroba. Quality changes of irradiated spices stored in various packaging materials. The changes in-quality of irradiated spices, i.e. nutmeg (Myristica fragrans), black pepper and white pepper (Piper nigrum) stored in various packaging materials were evaluated. Packaging materials used were tin can, tin can lined with polypropylene film, tin can lined with wrapping paper, woven polypropylene bag, find woven polypropylene bag lined with polypropylene film. The results showed that packaging in woven polypropylene bag could cause significant changes in the aw values and moisture contents of the spices, while in tin can no significant change was found during storage. By applying a polypropylene film lining inside the plastic bag, the changes could be retarded. The other parameters observed, i.e. total plate count, total mould and yeast count, and organoleptic scores of the samples, were not significantly affected by the packaging methods. A dose of 5 kGy could reduce the microbial load of the spices by about 2 - 3 log cycles. Prolonged storage caused significant decrease in the organoleptic properties of the spices. After prolonged storage, the microbial load of nutmeg and black pepper showed a significant decrease, while in white pepper a slight increase was observed.
INTRODUCTION In general, commercial spices such as black pepper, coriander, paprika, maces, white pepper, nutmeg, etc., contain high microbial load. The bacterial load ranges from 103 to 108 count/g or even higher as reported by BAXTER and HOLZAPPEL (1) and SAPUTRA et ai. (2). The use of irradiation to decontaminate spices proved to be effective (2,3,4). Results from the previous investigation (2) showed that a dose of 5 kGy could reduce the microbial load in black pepper, white pepper, and nutmeg by as much as 2 - 4 log cycles for total plate count and I - 3 log cycle,'>for total mould and yea·st count. In commercial practice, spices are commonly packed in jute sacks. However, such a packaging material cannot protect its content from insect infestation and mi*
Centre for the Application of Isotopes and Radiation, Natonal Atomic Energy Agency.
161
crobial contamination
during storage and transportation.
Therefore, it is considered
necessary to find a suitable packaging material for irradiated spices to stabilize the quality. HIGHLAND (5) reported that a tightly sealed polypropylene (PP) film overwrap can significantly increase the resistance of rigid or semi rigid unit packages; against insect infestation. Polypropylene film is also an excellent moisture and gas barrier (6), so that it is able to protect the content from moisture gain or loss. MAHA et al. (7) reported that irradiation doses of up to 10 kGy did not give a significant effect on the physical properties of woven polypropylene bag. Therefore, woven polypropylene bag lined with polypropylene film seems to be suitable for packaging irradiated spices. Tin container, which are commonly used for packaging dried products, such as tea, cashewnut, roasted coffee, may also be considered for packaging irradiated spices, as according to KILLORAN (8), irradiation has no effect on the tensile properties of tin plates. Commercial tin cans have also been reported to be suitable for packaging radappertized beef (9). The present study was undertaken to evaluate chemical, microbiological and sensory changes of irradiated spices packaged in woven polypropylene bags and tin cans. MATERIALS AND METHODS Materials. Whole nutmeg, black pepper, and white pepper, respectively obtained from Manado, Lampung, and Pangkal Pinang, were used for the experiment. The packaging materials used were tin cans of 10.7 cm diameter and 11.7 cm height, and polypropylene woven bags, both were obtained from producers in Jakarta. Polypropylene (PP) film, 0.06 mm thick,: and commercial wrapping paper were used as inner linings for the tin can and the polypropylene woven bag. Sample Preparations and Treatments. Samples of black and white pepper were sorted, and sun-dried upon arrival at the laboratory to reduce the moisture content to about 10%. The nutmeg could be used directly without additional drying since the moisture content was already low enough, i.e. about 7%. The samples were .packed using 5 different methods: 1. In tin cans without inner lining (TC) 2. In tin cans lined with PP film (TC + PPF) 3. In tin cans lined with wrapping paper (TC + WP) 4. In woven PP bags without inner lining (WPB) 5. In woven PP bags lined with PP film (WPB + PPF) The packed: '>amples were then irradiated with 0 and 5 kGy in a panoramic batch type 60CO' irradiator and stored at room temperature (29 ± 1°C). The samples were examined periodically every 3 months from 0 up to 9 months storage. The parameters observed were total plate count (TPC), total mould and yeast count (TMYC), moisture content, aw-values, and organoleptic properties, i.e. odour and flavour. This experiment was conducted with 2 replications. 162
Methods of Analysis. Moisture contents were measured using toluol distillation method and aw-values were determined using Hygroline Recorder Model VFB produced by Beckman. TPC and TMYC were determined by streak plate method respectively on plate count agar and Sabouraud dextrose agar media. Subjective evaluation for odour and flavour was done by submitting the samples to 10 panelists using a 9-point hedonic scale (9 = liked extremely, 5 = neither liked nor disliked, 1 = disliked extremely). Visual inspections consisted of observations on mould growth and insect infestation on the samples. Results obtained were evaluated statistically using analysis of variance followed by Duncan's new multiple range test. RESULTS AND DISCUSSIONS
Effects of packaging methods on qualities of nutmeg, black pepper and white pepper are summarized in Table I. It shows that, regardless of storage period, aw and moisture content of nutmeg packed in tin cans were higher than those packed in woven PP bags. However, for black pepper and white pepper the aw and moisture contents wre found to be higher in samples packed in woven PP bag. The changes in the aw and moisture contents of irradiated nutmeg may be caused by the fact that nutmeg releases moisture, whereas black and white pepper absorbs moisture through the pack. In general, the packaging methods did not affect the microbial load and organoleptic attributes of the spices. Table 2 summarized the effect of irradiation on the qualities of the spices. A dose of 5 kGy could reduce the TPC of nutmeg, black pepper and white pepper, respectively by 2, 3.4, and 2.4 log cycles, whereas the TMYC decreased by 2.5 log cycles for nutmeg, 2.7 log cycles for black pepper, and 2.6 log cycles for white pepper. Irradiation dose of 5 kGy did not affect the aw and moisture content of black and white pepper, and the odour and flavour of nutmeg. The changes in the aw and moisture content of irradiated nutmeg, and in the odour and flavour of irradiated pepper might be caused by the variability of the samples. Effects of storage periods on the qualities of nutmeg,-black and white pepper are presented in Table 3. It shows that the aw-values and moisture contents of the spices fluctuated during storage. This fluctuations is probably due to the fluctuation of the relative humidity in the surrounding air during the storage period i.e. 70 - 90%. The changes only occur in samples packed in non-air-tight packaging materials, such as polypropylene woven bags, as the samples can release or absorb moisture through the package to reach an equilibrium with the humidity of the environment. After storage, the microbial load of nutmeg and black pepper showed a significant decrease, while in white pepper a slight increase was observed. The fact that prolonged storage reduces microbial counts in spices is in conformation with the results of the previous experiment (2). The decrease might be caused by the low aw of the samples, i.e. 0.68 for nutmeg, 0.50 for white pepper and 0.52 for black 163
pepper. These aw·values are below the aw ranges for growth of bacteria, yeast and mould, therefore microbial growth can be suppressed as reviewed by TROLLER (10). Furthermove, the decrease in microbial counts of the spices may also be caused by the essential oils of the spices which have antimicrobial activities as reported by some investigators (11,12,13,14). No mould growth was observed in both irradiated and unirradiated samples. Insect infestations were found only in unirradiated nutmeg. CONCLUSIONS From the results, it can be concluded that packaging of spices in air-tight packaging materials such as in tin cans or woven plastic bag lined with polypropylene fIlm can avoid changes in moisture content or aw-values of spices during storage. Irradiation dose of 5 kGy can reduce the microbial load of spices by about 2 - 3 log cycles. A substantial reduction in microbial load of the spices containing less than 10% moisture can occur due to prolonged storage. Organoleptic properties of the spices also decrease after prolonged storage. AKCNOWLEDGEMENTS This study is partly supported by the IAEA under research contract No. 2630/ RI/JN. Were are grateful to Mrs. T. Erlinda, Mr. A. Bachtiar, and Mr. Darmawi for their technical assistance. REFERENCES 1. BAXTER, R., and HOLZAPFEL, H., A microbial investigation of selected spices, herbs, and additives in South Africa, J. of Food ScL 47 (1982) 571. 2. SAPUTRA, T.S., HARSOYQ, and SUDARMAN, H., "Gamma Irradiation of spices", Seminar on Food Irradiation for Developing Countries in Asia and the Pacific, Tokyo (1981). 3. GOTTSCHALK, H.M., A review on spices, present status of decontamination techniques such as gamma irradiation, Food Irradiation Information 7 (1977) 7. 4. FARKAS, J., Irradiation of spices and condiment, IFFIT Report 20 (1981). 5. HIGHLAND, H.A., GUY, R.H., and LAUDANI, H., Polypropylene vs insect infestation, Mod. Pack. 41 (1968) 113. 6. HANLON, J.F., Handbook of Package Engineering, McGraw-Hili Book Company, Inc., New York (1971). 7. MAHA, M., PURWANTO, Z.1., and KICKY, L.T.K., "Studies on bulk packaging of irradiated dried fish", Seminar on Food Irradiation for Developing Countries in Asia and the Pacific, Tokyo (1981). 8. KILLORAN, J.J., Chemical and physical changes in food packaging materials exposed to ionizing radiation, Radiation Res. Rev. 3 (1972) 369. 9. KILLORAN, 1.1., HOWKER, J.J., and WIERBICKI, E., Reliability of the tin plate can for packaging for radappertized beef under production conditions, J. of Food Processing and Preservation 3 (1979) 25. 10. TROLLER, J.A., Influence of water activity on microorganisms in foods, Food Tech. 34 5 (1 '.>80) 76.
11. HITOKOTO, H., MOROZUMI, S., WAUKE, T., SAKAI, S., and KURATA, H., Inhibitory effects of spices on growth and toxin production of toxogenic fungi, Appl. Environ. MicrobioI. 39 (1980) 818. 12. BULLERMAN, L.B., LIEU, F.Y., and SEIER, S.A., Inhibition of growth and aflatoxin production by cinnamon and clove oils, Cinnamic aldehyde and Eugenol, J. of Food Sci. 42 (1977) 1107.
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13. SHELEF, L.A., NAGLlK, O.A., and BOGEN, D.W., Sensitivity of some common food borne bacteria to the spices sage, rosemary, and allspice, 1. of Food Sci. 45 (1980) 1042. 14. LLEWELLYN, G.G., BURKETT, M.L., and EADIE, T., Potential mould growth, aflatoxin production, and antimycotic activity of selected natural spices and herbs, 1. Assoc., of Anal. Chern. 64 (1981) 955.
Samples
2.63 3.09 5.62 0.473 0.481 3.31 6.1 4.30 5.48 2.44 2.06 6.0 3.11 6.6 2.65 2.81 2.48 2.42 2.56 2.41 5.9 0.642 2.75 2.65 0.678 0.673 0.593 5.9 7.8 7.5 6.7 6.1 6.0 5.9 aacbC abc 4.25 6.5 cacbbc 5.60 2.25 Flavour aT 8.9 5.94 4.12 3.94 5.89 6.0 4.00 0.476 0.495 2.56 6.4 2.99 0.466 0.501 3.45 0.520 3.42 10.3 8.7 8.9 9.9 9.0 6.2 6.5 TC bab a(%) 9.5 b 7.1 Odour TMYC 0.472 TPC Aw-value Packaging g) M.C. (log (log count/ value5 each sample in count{ the on same whichTMYC, are notodour, followed by the 1. Effect offorpackaging methods aw,column MC, TPC, and flavour TableMean Black g) pepper same letterof are significantly different ';;;;;0.05). nutmeg, black pepper and (Pwhite pepper*.
Table
2.
Effect
of irradiation
ur of nutmeg,
treatment
on aw, MC, TPC, TMYC, odour,
and flavo-
black pepper and white pepper*.
Flavour 6.1 6.5 6.1 7.43 2.94 7.8 3.59 1.51 9.2 5.34 6.8 9.4 6.9 8.9 6.0 aa0.481 a0.493 0.99 3.98 4.57 0.661 1.51 0.491 3.71 0.477 1.95 ababab abb ba(kGy) TPC TMYC 5.9 6.3 6.4 5.9 6.3 3.98 a0.624 bcount/g) 0dose Odour MC Irradiation aw-value (%) (log count/g) Mean values for(log each sample in the same column same letter are significantly different (P ';;;;;0.05).
which are not followed
by the
165
Samples
0.594 2.91 6.12 2.50 4.18 3.97 3.39 0.458 20.614 0.532 0.499 5.5 2.21 2.04 5.6 3.42 6.8 0.464 9.0 3.52 7.7 2.62 0.661 7.2 3.01 6.5 8.2 2.48b 0.467 9.2 6.4 0.523 6.0 6.1 9.3 0.472 3.33 3.22 3.06 .34 ba7.0 6.7 6.6 6.5 6.2 b5.3 6.0 5.7 daebcbeababdcbecabe0for 4.14 4.29 lAOe TPC 5.60 5.500.701 2.15 5.8 M.C 6.3 8.5 9.9 9.1 Flavour 6.0 Odour 6.1 Storage 6.0 aw-value (%)sample in the same column which are not followed by the g) count/ countl TMYC values each TableMean 3.(log Effect of(log storage on aw, MC, TPC, TMYC, odour, and flavour of nutmeg, g) same letter are pepper significantly different (p ~O.O5). black and white pepper.
166
DlSKUSI
NELLY: Bahan kemasan yang kedap seperti kaleng akan memberikan kadar air yang lebih tinggi daripada dalam kemasan yang porous seperti karung plastik. Dalam uraian Bapak pada lada hitam justru diperoleh hasil yang bertentangan. Dapatkah dijelaskan apa kira-kira penyebabnya. TJETJE S. SAPUTRA: Hal ini mungkin disebabkan oleh perbedaan "sorption isotherm" daripada rempahrempah yang dikemas dalam karung plastik. Biji pala melepaskan air dan lada hitamjputih menyerap air selama penyimpanan. T. KAWABATA: Did you check aflatoxin levels in the irradiated and control spices. If not, I hope you check the levels in the future study. TJETJE S. SAPUTRA: No, we didn't. However, we just start doing experiment on the growth and aflatoxin production of A. flavus on ground nutmeg this year. SOEWARDJO ADIKOESOEMO: I.
2.
Dalam penjelasan anda lewat slide mengemukakan bahwa iradiasi pada rempahrempah hasil penelitian anda terdapat fluktuasi kadar H2 O. Menurut argumentasi anda, karena keadaan gudang yang berubah-ubah. Hal ini tak mungkinjtak benar, karena hal ini hanya dapat terjadi pada keadaan musim kemarau dan musim hujan (musim pancaroba). Jadi kalau penelitian anda dilakukan pada musim kemarau, maka fluktuasi kadar H20 tidak akan terjadi. Pasti ada sebab yang lain, yang belum anda ketemukan jawabannya. Mengenai kemasan yang anda ajukan ialah pakai karung plastik dan kaleng. Menurut anda apabila kemasan karung plastik rusak, maka hasil iradiasi pada rempah-rempah tidak ada gunanya, karena akan terkontaminasi lagi. Jadi saya sarankan agar pakai saja kaleng. Dalam praktek karung-karung plastik atau karung-karung lainnya pasti mendapat kerusakan pada saat dibongkar di pelabuhan. Hal ini disebabkan kuli-kuli di pelabuhan selalu memakai alat-alat besi untuk mempermudah mengangkut barang-barang tersebut, tidak perduli barang tersebut menjadi rusak. (Hal ini sudah membudaya di kalangan kuli pelabuhan, meskipun pada karung plastik ditulis "JANGAN DlGANCO".)
TJETJE S. SAPUTRA: Terima kasih atas saran-sarannya. HOUSEIN BAADlLLA: Perlu dilakukan studi dari semua grade. Juga agar memakai pembungkus karung yang biasa dipakai di dunia perdagangan. TJETJE S. SAPUTRA: I. 2.
Biji pala yang diteliti kualitas ABCD. Lada putihjhitam kualitas FAO. Terima kasih atas saran-sarannya. 167
