Risalah Seminar Nasional Pengawetan Makanan Dengan Iradiasi, Jakarta, 6 - 8 Juni 1983

QUALITY CHANGES OF IRRADIATED SPICES STORED IN VA­RIO US PACKAGING MATERIALS

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 filmpolipropilen, kaleng yang bagian dalamnya dilapisi kertas merang, karung plastik polipropilendan karung plastik polipropilen yang bagian dalamnya dilapisi film polipropilen. Hasil penelitianmenunjukkan bahwa dengan karung plastik polipropilen dapat menyebabkan perubahan nyatapada kadar air dan aktivitas air sedang pengemasan dengan kaleng tidak memberikan perubahanselama penyimpanan. Dengan menggunakan lapisan film polipropilen pada bagian dalam karungplastik, perubahan-perubahan tersebut dapat dihambat. Angka total mikroba, angka totalkapang dan khamir, dan nilai organoleptik rempah-rempah tidak dipengaruhi oleh cara penge­masan. Dosis 5 kGy dapat mengurangi kandungan mikroba rempah-rempah sebanyak 2 - 3 "logcycles". Penyimpanan dalam waktu lama menyebabkan perubahan sifat-sifat organoleptikrempah-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 changesin-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 usedwere tin can, tin can lined with polypropylene film, tin can lined with wrapping paper, wovenpolypropylene bag, find woven polypropylene bag lined with polypropylene film. The resultsshowed 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 foundduring storage. By applying a polypropylene film lining inside the plastic bag, the changes couldbe 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. Afterprolonged 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 rangesfrom 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·stcount.

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 EnergyAgency.

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crobial contamination during storage and transportation. Therefore, it is considered

necessary to find a suitable packaging material for irradiated spices to stabilize thequality. HIGHLAND (5) reported that a tightly sealed polypropylene (PP) filmoverwrap can significantly increase the resistance of rigid or semi rigid unit pack­ages; against insect infestation. Polypropylene film is also an excellent moistureand gas barrier (6), so that it is able to protect the content from moisture gain orloss. MAHA et al. (7) reported that irradiation doses of up to 10 kGy did not givea significant effect on the physical properties of woven polypropylene bag. There­fore, woven polypropylene bag lined with polypropylene film seems to be suitablefor packaging irradiated spices.

Tin container, which are commonly used for packaging dried products, such astea, 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 forpackaging radappertized beef (9).

The present study was undertaken to evaluate chemical, microbiological andsensory changes of irradiated spices packaged in woven polypropylene bags andtin cans.

MATERIALS AND METHODS

Materials. Whole nutmeg, black pepper, and white pepper, respectively obtainedfrom 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 cmheight, and polypropylene woven bags, both were obtained from producers inJakarta.

Polypropylene (PP) film, 0.06 mm thick,: and commercial wrapping paperwere used as inner linings for the tin can and the polypropylene woven bag.

Sample Preparations and Treatments. Samples of black and white pepper weresorted, and sun-dried upon arrival at the laboratory to reduce the moisture contentto about 10%. The nutmeg could be used directly without additional drying sincethe 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: '>ampleswere then irradiated with 0 and 5 kGy in a panoramicbatch type 60CO' irradiator and stored at room temperature (29 ± 1°C).

The samples were examined periodically every 3 months from 0 up to 9months storage. The parameters observed were total plate count (TPC), total mouldand yeast count (TMYC), moisture content, aw-values, and organoleptic properties,i.e. odour and flavour.

This experiment was conducted with 2 replications.

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Methods of Analysis. Moisture contents were measured using toluol distillationmethod and aw-values were determined using Hygroline Recorder Model VFB pro­duced by Beckman.

TPC and TMYC were determined by streak plate method respectively on platecount 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 = neitherliked 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 followedby Duncan's new multiple range test.

RESULTS AND DISCUSSIONS

Effects of packaging methods on qualities of nutmeg, black pepper and whitepepper are summarized in Table I. It shows that, regardless of storage period, awand 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 bythe fact that nutmeg releases moisture, whereas black and white pepper absorbsmoisture 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. Adose 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 2.5log cycles for nutmeg, 2.7 log cycles for black pepper, and 2.6 log cycles for whitepepper. Irradiation dose of 5 kGy did not affect the aw and moisture content ofblack and white pepper, and the odour and flavour of nutmeg. The changes in theaw 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 pepperare presented in Table 3. It shows that the aw-values and moisture contents of thespices 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 packagingmaterials, such as polypropylene woven bags, as the samples can release or absorbmoisture through the package to reach an equilibrium with the humidity of theenvironment.

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 thatprolonged storage reduces microbial counts in spices is in conformation with theresults of the previous experiment (2). The decrease might be caused by the low awof the samples, i.e. 0.68 for nutmeg, 0.50 for white pepper and 0.52 for black

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pepper. These aw·values are below the aw ranges for growth of bacteria, yeast andmould, therefore microbial growth can be suppressed as reviewed by TROLLER(10). Furthermove, the decrease in microbial counts of the spices may also becaused 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 polypropylenefIlm 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 - 3log cycles. A substantial reduction in microbial load of the spices containing lessthan 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 fortheir 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 techniquessuch 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 irradia­

ted dried fish", Seminar on Food Irradiation for Developing Countries in Asia and thePacific, Tokyo (1981).

8. KILLORAN, J.J., Chemical and physical changes in food packaging materials exposed toionizing radiation, Radiation Res. Rev. 3 (1972) 369.

9. KILLORAN, 1.1., HOWKER, J.J., and WIERBICKI, E., Reliability of the tin plate can forpackaging for radappertized beef under production conditions, J. of Food Processing andPreservation 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., Inhibitoryeffects 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 aflatoxinproduction 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 foodborne 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, aflatoxinproduction, and antimycotic activity of selected natural spices and herbs, 1. Assoc., ofAnal. Chern. 64 (1981) 955.

Table 1. Effect of packaging methods on aw, MC, TPC, TMYC, odour, and flavour

of nutmeg, black pepper and white pepper*.Samples

PackagingAw-valueM.C. (%)TPCTMYCOdourFlavourmethod

(log count{ (log count/g)

g)

Nutmeg

TC0.678 a7.8 a2.48 a2.41 a6.1 a5.9 aTC + PPF

0.673 a7.5 a2.63 a3.09 a6.1 a5.9 aTC + WP

0.642 b7.8 a2.42 a2.75 a6.0 a6.0 aWPB

0.593 c6.7 c2.56 a2.65 a5.9 a5.9 aWPB + PPF 0.627 b

7.1 b2.65 a2.81 a6.0 a5.9 a-- Black pepperTC0.495 b9.0 b5.89 a2.06 a6.2 a6.0 a

TC + PPF0.476 c8.7 c5.94 a2.44 a6.1 a6.1 a

TC+WP0.481 bc8.7 c5.62 a2.44 a6.1 a6.0 a

WPB0.520 a9.9 a5.48 a2.56 a6.2 a6.0 a

WPB + PPF 0.488 bc8.9 b5.60 a2.25 a6.1 a6.1 a

White pepper

TC0.473 b8.9 c4.25 a3.31 a6.6 a6.5 aTC + PPF

0.472 b8.9 c4.12 ab2.99 a6.6 a6.5 aTC + WP

0.466 b9.0 c4.30 a3.42 a6.6 a6.4 aWPB

0.501 a10.3 a4.00 b3.11 a6.5 a6.4 aWPB + PPF 0.483 b

9.5 b3.94 b3.45 a6.6 a6.4 a

*Mean value5 for each sample in the same column which are not followed by the

same letter are significantly different (P ';;;;;0.05).

Table 2. Effect of irradiation treatment on aw, MC, TPC, TMYC, odour, and flavo­

ur of nutmeg, black pepper and white pepper*.

Irradiationaw-valueMCTPC TMYCSamples

dose (kGy)(%)(log count/g) (log count/g)OdourFlavour

Nutmeg

00.661 a7.8 a3.59 a3.98 a6.1 a5.9 a5

0.624 b6.9 b1.51 b1.51 b5.9 a5.9 a

Black pepper

00.491 a8.9 a7.43 a3.71 a6.3 a6.1 a5

0.493 a8.9 a3.98 b0.99 b6.0 b5.9 b

White pepper

00.477 a9.2 a5.34 a4.57 a6.8 a6.5 a5

0.481 a9.4 a2.94 b1.95 b6.4 b6.3 b

*Mean values for each sample in the same column which are not followed by the

same letter are significantly different (P ';;;;;0.05).

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Table 3. Effect of storage on aw, MC, TPC, TMYC, odour, and flavour of nutmeg,black pepper and white pepper.

Samples

Storageaw-valueM.CTPCTMYCOdourFlavour(month)

(%)(log count/ (log countlg)

g)

Nutmeg

00.661 b7.2 c3.39 a3.52 a6.7 a6.3 a3

0.614 e6.4 e2.91 b2.62 b5.3 c5.6 d6

0.701 a8.2 a2.50 b2.48b6.0 b5.8 e9

0.594 c7.7 blAOe2.34 b6.0 b6.0 b

Black pepper

00.472 e8.5 e6.12 a3.01 a6.6 a6.5 a3

0.499 b9.3 a5.60 a2.04 b5.7 e5.5 e6

0.532 a9.1 b5.50 a2.21 b6.1 b6.1 b9

0.464 e9.0 b5.60 a2.15 b6.1 b6.0 b

White pepper

00.464 b9.0 b3.97 b3.42 a7.0 a6.8 a3

0.458 b9.2 b4.14 a3.22 a6.2 d6.4 b6

0.523 a9.1 b4.29 a3.06 a6.7 b6.4 b9

0.467 b9.9 a4.18 a3.33 a6.5 e6.3 b

*Mean values for each sample in the same column which are not followed by the

same letter are significantly different (p ~O.O5).

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DlSKUSI

NELLY:

Bahan kemasan yang kedap seperti kaleng akan memberikan kadar air yang lebihtinggi daripada dalam kemasan yang porous seperti karung plastik. Dalam uraianBapak 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 ladahitamjputih menyerap air selama penyimpanan.

T. KAWABATA:

Did you check aflatoxin levels in the irradiated and control spices. If not, I hopeyou 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. 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 mungkinjtakbenar, karena hal ini hanya dapat terjadi pada keadaan musim kemarau danmusim hujan (musim pancaroba). Jadi kalau penelitian anda dilakukan padamusim kemarau, maka fluktuasi kadar H20 tidak akan terjadi. Pasti ada sebabyang lain, yang belum anda ketemukan jawabannya.

2. Mengenai kemasan yang anda ajukan ialah pakai karung plastik dan kaleng.Menurut anda apabila kemasan karung plastik rusak, maka hasil iradiasi padarempah-rempah tidak ada gunanya, karena akan terkontaminasi lagi. Jadi sayasarankan agar pakai saja kaleng. Dalam praktek karung-karung plastik ataukarung-karung lainnya pasti mendapat kerusakan pada saat dibongkar di pe­labuhan. Hal ini disebabkan kuli-kuli di pelabuhan selalu memakai alat-alatbesi untuk mempermudah mengangkut barang-barang tersebut, tidak perdulibarang tersebut menjadi rusak. (Hal ini sudah membudaya di kalangan kulipelabuhan, 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 karungyang biasa dipakai di dunia perdagangan.

TJETJE S. SAPUTRA:

I. Biji pala yang diteliti kualitas ABCD. Lada putihjhitam kualitas FAO.2. Terima kasih atas saran-sarannya.

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