report on the analyses of the organic residues in archaeological
TRANSCRIPT
REPORT ON THE ANALYSES OF THE ORGANIC RESIDUES IN ARCHAEOLOGICAL SAMPLES FROM THE PROJECT “EXCAVATING
THE ROMAN PEASANT”.
A. Pecci, ERAUUB, Universitat de Barcelona M.A. Cau Ontiveros, ICREA/ ERAAUB, Universitat de Barcelona
Analyses of the organic residues in ceramics and plasters from the project Excavating the Roman peasant
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ANALYSIS OF THE ORGANIC RESIDUES IN CERAMIC AND PLASTERS FROM THE PROJECT “EXCAVATING THE ROMAN PEASANT” A. Pecci, ERAUUB, Universitat de Barcelona M.A. Cau Ontiveros, ICREA/ ERAAUB, Universitat de Barcelona 1. Introduction
Porous materials absorb the liquid and semi-liquid substances that came in contact with them. In
particular, almost 40 years of research have shown that through the chemical analysis of samples it
is possible to try to understand the original content of ceramic vessels (Condamin et al. 1976,
Evershed 2008).
This kind of analyses has an important application for the study of amphorae, and therefore of the
economy in the Mediterranean area in ancient times. The early stage of chemical analyses of
archaeological materials corresponded essentially to the study of amphorae content (Condamin et
al. 1976, Formenti et al. 1978, Rotshild-Boros 1981, Passi et al. 1981, Heron, Pollard 1988) and in
later years the study of contents has had a new impulse (Garnier 2004, 2007a, 2007b Brun 2004,
Romanus et al. 2009, Pecci 2009). Still, there is still a lot of work to do. Sometimes, in fact, the
analyses offer data that are consistent with those proposed by the literature, while some other times
the content is similar to that one expected, although a little different. Finally, in some cases, they
show new and unexpected data (Pecci et al in press.). This is why it is more and more important to
establish on scientific bases the contents of the different types amphorae, in order to give
consistency to the hypothesis on the goods stored and transported in them, and therefore to
understand ancient economy.
The analyses carried out on some materials recovered during the Project “Excavating the Roman
peasant” have the objective of clarifying if several local-regional amphorae were devoted to contain
wine and to understand the food prepared in two coarse ware cooking vessels.
Residues analysis can also be performed on porous materials different from ceramics, such as
plasters (Barba 1986, 2007). At La Pievina, the plaster coating of a basin was sampled, in order to
try to understand the function of the basin and therefore try to identify food production markers at
the site.
A. Pecci and M.A. Cau, Equip de Recerca Arqueològica i Arqueomètrica de la Universitat de Barcelona
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2. Materials and methods
Materials
Two samples (1-2) were taken from the plastered coatings of a basin. Six samples were
taken from amphorae locally and/or regionally produced, showing a different chronology to test if
changes raised in time, and in particular in Late Antiquity. Two samples were taken from import
amphorae (one K26 and one K25 or 26) and, finally, two samples were taken from Late Roman
cooking ceramic vessels (a testo or pan and a pot) to verify the food cooked in them (Table 1).
Table 1. Samples analysed. sample n. sample id.
laboratory n. part sampled
1 CN2010 -1-US 5005 62 basin us 5005 Plaster 2 CN2010 -2 US 5005 63 basin us 5006 Plaster 3 inv.1010157 64 amphora local-regional Neck 4 inv.1010036 65 amphora local-regional Bottom 5 inv. 1010144 66 amphora local-regional Wall 6 US 5048 67 amphora local-regional Wall 7 US 5014 70 amphora local-regional Wall 8 US 5014 71 amphora local-regional Wall 9 inv.1010130-US 1019 68 amphora K26 Bottom 10 inv.1010090-US 1026 69 amphora K25 or 26 Botom 11 olla inv.1010180-US 1006 72 Cooking pot Bottom 12 testo inv 1010090- 73 Cooking pan Bottom
Methods
Each sample was cleaned mechanically before it was sub - sampled in the laboratory. No
samples of the earth that was in contact with the ceramic vessels and the basin were recovered,
therefore we could not have a blank sample for the analysis.
The samples were studied by the ERAAUB, using the infraestructure of the Archaeometric
Laboratory of the Departament de Prehistòria, Història Antiga i Arqueologia of the Facultat de
Geografia i Història (UB), where the samples were crushed, and the infraestructure of the Serveis
Científico-Tècnics de la Universitat de Barcelona, where the samples were analyzed with
gaschromatografy – mass spectometry (GC-MS).
The ceramic and plaster samples were analysed using the following methodology:
a. The total lipid extract was obtained following the procedure described by Mottram et al. (1999):
Analyses of the organic residues in ceramics and plasters from the project Excavating the Roman peasant
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1g of grounded sample was extracted twice with CHCl3/MeOH (2:1 v/v, 3 ml) in sonicated bath for
40 min. at 70°C. 5 µl of a standard solution of octacosane (3 mg/ml) were added to the powder before
extraction. The liquid fraction was recovered after centrifugation and dried using a gentle stream of
nitrogen.
b. Half of the total lipid extract was extracted with KOH in methanol (1 M, 6 ml), leaving overnight.
The day after 6 ml of water were added and acidified. CHCl3 (2x3 ml) was added and mixed with a
vortex. The extract was separated and dried using a gentle stream of nitrogen.
c. For some samples, the solid fraction of each sample was extracted with KOH (1 M, 3 ml) in a
sonicated bath at 70°C for 90 min. After cooling and centrifugation, the liquid fraction was recovered
and acidified. CHCl3 (2x3 ml) was added and mixed with a vortex. The extract was separated and
dried using a gentle stream of nitrogen.
d. For the identification of wine markers, the extraction with KOH was repeated with 500 mg of
sample. This time 3 ml of ethyl acetate were added twice to the liquid fraction and mixed with the
vortex. They were then separated and dried using a gentle stream of nitrogen.
All the extracts were derivatized adding 25µl of N,O-bis(trimethylsilyl)trifluoroacetamide
(BSTFA, Sigma-Aldrich) and heating at 70°C for 1h. 75 µl of hexane were added and 5 µl of a
standard (dotriacontano - 1 mg/mL). For the analysis 1 µl was injected.
The analysis were performed with a chromatographer Thermo Scientific TS GC ultra, with a
30 m x 0.25 mm (i.d.) x 0.25 µm film thickness fused silica capillary column and a mass
spectrometer Thermo Scientific ITQ 900 operated in electronic ionization (70 eV).
The mass range was scanned in the range of m/z 40-650. The oven temperature of the GC was
kept at 50°C for 1 min, and then raised of 5°C/min until the 330°C and kept constant for 10 min.
3. Results
Samples 1-2 sample n. sample id.
laboratory n. part sampled
1 CN2010 -1-US 5005 62 basin us 5005 Plaster 2 CN2010 -2 US 5005 63 basin us 5006 Plaster
In the total lipid extract of sample 2 the main picks after the standard are oleanitrile and
oleammide (Figures 1 and 2). Also in the hydrolisis of the total lipid extract oleamide is the main
pick. The presence of these compounds could be due to a reaction of oleic acid in a basic
environment, and could therefore be attributed to the presence of a vegetable oil in the sample.
A. Pecci and M.A. Cau, Equip de Recerca Arqueològica i Arqueomètrica de la Universitat de Barcelona
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These compounds were also identified in African amphorae filled with
lime and/or plaster and supposed to have contained oil, that were recovered at Pompei during the
“Garum Workshop project” directed by Bernal and Cottica and studied by the authors of this
contribution.
In the ethyl-acetate extraction, also traces of azelaic acid are present. This compound is
considered to be a by-product of the degradation of oleic acid (Dudd et al 1998).
Figure 1. Chromatogram of the total lipid extract of sample 2 (basin).
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Figure 2. Spectra of the oleanitrile in the sample (top) and in the Nist library (bottom).
Figure 3. Oleamide spectra in the sample (top) and in the Nist library (bottom).
a.(TextFile)10091312#1848RT:32.98AV:1 40
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Samples 3, 4 and 5
sample n. sample id.
laboratory n. part sampled
3 inv.1010157 64 amphora local-regional Neck 4 inv.1010036 65 amphora local-regional Bottom 5 inv. 1010144 66 amphora local-regional Wall
Samples 3, 4 and 5 come from local-regional amphorae.
While sample 3 is not rich in residues, sample 4 shows very abundant traces of resin/pitch:
dehydroabietic acid is in fact the main pick together with 7 oxodehydroabietic, and abietic acid is
also present.
The abundance of resin in sample 4 could be due to the fact that the amphora was coated with a lot
of pitch, and part of this pitch could have accumulate in the bottom of the amphora
Although in sample 4 the tartaric acid, usually considered to be the marker of wine (Guash Jané et
al 2004, Mc Govern 2004) is absent, there are other compounds that are present in wine, such as
malonic, benzoic, vanillic, succinic, and cinnamic acids, that in sample 9 were identified together
with tartaric acid. These acids, could support the archaeological hypothesis that the amphora
contained wine. In this case, the resin could have also had the function of flavouring the wine.
Sample 5 is also rich in residues. Here, like in sample 4, although no tartaric acid was identified,
other compounds that are usually found in wine are present in the ethylacetate extract (succinic,
benzoic, malonic and vanillic acids). Traces of resin were identified also in this sample, while no
traces of vegetables oils were present in the samples.
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Fugure 4. Chromatogram of the total lipid extract of sample 4. METTERE figura ETO DI 4 e o 5 Figure 5. Ethyl acetate extract of sample... Samples 6, 7 and 8 sample n. sample id.
laboratory n. part sampled
6 US 5048 67 amphora local-regional Wall 7 US 5014 70 amphora local-regional Wall 8 US 5014 71 amphora local-regional Wall
The analysis of samples 6, 7 and 8, taken from local or regional amphorae show almost no
residues, as the relative proportion to the standards in the total lipid extracts suggests (Figures 6 and
7). In samples 6 and 8, some traces of resin are present, possibly used to coat the amphorae, while
in sample 7, long chain fatty acids such as C20, C21, C22 and C24 were identified. These compounds
could be related with the presence of waxes.
Fugure 6. Chromatogram of the total lipid extract of sample 7 (laboratory 70).
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A. Pecci and M.A. Cau, Equip de Recerca Arqueològica i Arqueomètrica de la Universitat de Barcelona
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Fugure 7. Chromatogram of the total lipid extract of sample 8. Sample 9 (laboratory 68)
sample n. sample id.
laboratory n. part sampled
9 inv.1010130-US 1019 68 amphora K26 Bottom
The analyses of the K 26 amphora (sample 9) allowed to identify tartaric acid both in the
ethylacetate extraction and in the total lipid extract. Tartaric acid is commonly considered to be the
marker of wine. Besides this acid, also other compunds that are typical of wine were identified
(malic, malonic, benzoic, and succinic acids).
Traces of resin are present in all the extractions of the sample.
Azelaic acid and 9,10 - dihydroxyoctadecanoic acids are present in the hydrolyses. These
compounds are usually considered among the markers of oil. Nevertheless, C18:1 is not high and
more data are needed to establish if an oil could have been contained in the amphora. If this was the
case, we could suggest that the amphora was re-used, as it is possible to exclude that oil and wine
were carried together.
The data obtained for this amphora are interesting, as they provide more material for the
discussion on the goods that this kind of amphorae carried. They are in fact supposed to have
carried wine or fish sauces; but the analysis of five K 26 recovered in the port of Classe showed
castor oil residues (Pecci et al in press).
Like in the amphorae coming from Classe, this one had a resin/pitch coating.
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Analyses of the organic residues in ceramics and plasters from the project Excavating the Roman peasant
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Figure 8. Chromatogram of the hydrolysis in ethyl acetate of sample 9.
Figure 9. Particular of the chromatogram of the hydrolysis in ethyl acetate of sample 9. The markers of wine can be observed here.
Sample 10 (laboratory 69)
sample n. sample id.
Laboratory n. part sampled
10 inv.1010090-US 1026 69 amphora K25 or 26 Bottom
Sample 10, belonging to a K 25 or K 26 amphora, is very rich in pitch. Dehydroabietic acid,
together with 7 - oxodehydroabietic acid are in fact very aboundant in all the extracts. In the
hydrolisis of the total lipid extract also the methyldehydroabietic acid, considered to be the marker
of the distillation of pitch directly from the wood (Colombini et al 2005) is present (Figure..).
The pitch probably due to presence of the coating of the amphora, is so abundant that it might have
Tartaric acid
malonic acid
fumaric acid
malic acid
succinic acid
benzoic acid
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A. Pecci and M.A. Cau, Equip de Recerca Arqueològica i Arqueomètrica de la Universitat de Barcelona
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prevent at least part of the residues of the content from penetrating the
ceramic body. In any case, malonic, benzoic, succinic, glutaric and vanillic acids are present in the
extraction for the wine markers, suggesting a wine content.
Fugure 10. Chromatogram of the hydrolisis on half of the total lipid extract of sample 10.
Fugure11. Spectra of the methyl dehydroabieticacid present in the NIST library (left) and obtained with the analysis of sample 10 (right).
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Analyses of the organic residues in ceramics and plasters from the project Excavating the Roman peasant
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Fugure 12. Spectra of the dehydroabieticacid obtained with the analysis of sample 10 and present in the NIST library (bottom).
Sample 11
sample n. sample id.
laboratory n. part sampled
11 olla inv.1010180-US 1006 72 Cooking pot Bottom Sample 11 was taken from a cooking pot. The abundance of the stearic acid together with the
cholesterol present in some of the extracts, suggests the animal origin of the fats. Although no
isotopic analyses were performed, the presence of branched odd fatty acids such as C15 and C17
suggest that the fat derives mainly from ruminant animals (Mottram et al 1999).
These data are simirar to those obtained with the analysis of Late Roman and Medieval cooking
pots analysed by the authors of this contribution.
A. Pecci and M.A. Cau, Equip de Recerca Arqueològica i Arqueomètrica de la Universitat de Barcelona
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Fugure 13. Chromatogram of the hydrolisis on half of the total lipid extract of sample 11. Sample 12
sample n. sample id.
laboratory n. part sampled
12 testo inv 1010090- 73 Cooking testo/pan Bottom
Sample 12 was taken from a possible testo or pan. It has abundant residues as it is shown by the
proportion with the standards that can be observed in Figure 13. Like in sample 11, the presence of
cholesterol and the abundance of the stearic acid suggest the animal origin of the fats. Although no
isotopic analyses were performed, the presence of branched odd fatty acids such as C15 and C17
suggest that the fat derives mainly from ruminant animals (Mottram et al 1999).
The quantity of animal origin residues suggests that it is more likely that thevessel was a pan than a
testo. Testi are in fact usually considered to have been used to cook bread or similar foodstuff
(Quiros Castillo 1998, Pruno 2003). Although the analysis of some medieval testi coming from
Tuscan archaeological sites have shown that some of them were possibly used to cook animal origin
products or to serve them on the table (Pecci 2009), the amount of residues present in this ceramic
vessel suggests an intense use for the cooking of animal fats, similar to the one usually performed in
pots or pans.
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Analyses of the organic residues in ceramics and plasters from the project Excavating the Roman peasant
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Fugure 13. Chromatogram of the total lipid extract of sample 12.
4. Conclusiones
The results of the analyses allowed to recover in formation on the use of the amphorae and
the basin found at La Pievina.
Some of the amphorae showed residues that could be related with their use, such as the wine
markers present in the K26 and possibly in other amphorae. In other cases no residues were
identified. This could be attributed to the fact that they degraded because of the aging or the post-
depositional processes, nevertheless it is also possible that these amphorae were used for the
storage and transport of water and/or substances that do not leave traces that can be identified with
the analyses performed.
Aknoledgemnts
The samples were analized at the Serveis Científico-Tècnics of the Universitat de Barcelona
in the department of gas chromatography. This report is part of the activities of the project
“Production, trade and consumption of food in Late Antiquity” (PROFOLANT), PIEF-GA-2009-
235863, 7th Framework Programa, People, Marie Curie actions, IEF.
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C181
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cholesterol
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References
Brun J.P.(ed.), Archaeologie du vin et de l’huile dans l’Empire romain, Paris: 30-31.
Condamin J., Formenti F., Metais M.O., Michel M., Bond P., 1976, The application of Gas
Chromatography to the tracing of oil in ancient amphorae, Archaeometry, 18 (2): 195-201
Colombini M. P., Modugno F., Ribechini E, 2005, Direct exposure electron ionization mass
spectrometry and gas chromatography/mass spectrometry techniques to study organic
coatings on archaeological amphorae, Mass Spectrometry, 40: 675-687.
Dudd S., Regert M., Evershed R., 1998, Assessing microbial lipid contributions during laboratory
degradations of fats and oils pure triacylglycerols absorbed in ceramic potsherds, Organical
Geochemistry, 29, 5-7, 1998: 1345-1354.
Evershed R., 2008, Organic residues in archaeology: the archaeological biomarker revolution,
Archaeometry, 50, 6: 895-924.
Formenti F., Hensard A., Tchernia A., 1978, Note sur le contenu d’une amphore Lamboglia 2 de
l’épave de la Madrague de Giens, Archaeonautica, 2: 95-110.
Garnier N. 2004, L’apport des anályses chimiques à la determination des récipients ayant contenu
du vin ou de l’huile, in Brun J.P.(ed.), Archaeologie du vin et de l’huile dans l’Empire
romain, Paris: 30-31.
Garnier N., 2007, Annexe: analyse du contenu des amphores africaines, en Papi E. (ed.) Supplying
Rome and the Empire. Proceedings of an International Seminar (Siena 2004), Porthsmouth,
Rhode Island, pp. 25-31.
Guash-Jané M.R., Iberno Gómez M., Andrés-Lacueva C., Jáuregui O., Lamuela-Raventós R.M.,
2004, Liquid Chromatography with Mass Spectrometry in Tandem Mode applied for the
Identification of Wine Markers in Residues from Ancient Egyptian Vessels, Analytical
Chemistry, 76, 6: 1672-1677.
Heron C., Pollard A.M., 1988, The Analysis of Natural Resinous Materials from Anphoras, Science
and Archaeology, Oxford 1988 [Glasgow 1987].
McGovern P., 2004, L’archeologo e l’uva, Roma.
Passi S., Rotschild-Boros M., Fasella P., Nazzaro-Porro M., Whitehouse D., 1981, An application of
high performance liquid chromatography to analysis of lipids in archaeological semples,
Journal of Lipid Research, 22:778-784.
Pecci A., 2009, Analisi funzionali della ceramica e alimentazione medievale, Archeologia
Medievale, 36: 21-42.
Pecci A., Salvini L., Cirelli E., Augenti A., c.s. Residue analysis of some Late Roman amphorae
Analyses of the organic residues in ceramics and plasters from the project Excavating the Roman peasant
16
coming from the port of Classe (Ravenna – Italy): Relationship between form and function,
in LRCW3. Late Roman Coarse Wares, Cooking Wares and Amphorae in the
Mediterranean. Archaeology and archaeometry (Parma-Pisa 2008), Menchelli S.,
Pasquinucci M., Santoro S.(eds.), BAR International Series, Oxford.
Pruno E., 2003, La diffusione dei testelli nell'Alto-Tirreno tra XI-XIV sec, in III Congresso
Nazionale di Archeologia Medievale a cura di Fiorillo R., Peduto P., Firenze, pp. 71-77.
Quiros Castillo J. A., 1998, Cambios y transformaciones en el paisaje del Apenino Toscano entre la
Antigüedad Tardía y la Edad Media. El castaño, Archeologia Medievale, XXV, pp. 177-
197.
Romanus K., Baeten J., Poblome J., Accardo S., Degryse P., Jacobs P., De Vos D., Waelkens M.,
2009, Wine and olive oil permeation in pitched and non-pitched ceramics: relation, with
results from archaeological amphorae from Sagalassos, Turkey, Journal of Archaeological
Science, 36: 900–909.
Rotshild-Boros M.C., 1981, The Determination of Amphora Contents, in Archaeology and Italian
Society, Barker G., Hodges R.(eds.), BAR International Series, Oxford, pp. 79-89.