Research on hardened daub fragments provides highly relevant data on the building activities of past societies. Unfortunately, in many cases these elements are not considered relevant research objects, resulting in a very important loss of information for archaeology. There is still a long way to go in the studies of earth building remains, the vast majority of which have focused on assemblages coming from specific sites. Likewise, a good number of these studies carried out from a macroscopic approach either have not published the methodology used or barely offer some considerations about it. This article approaches the methodological procedures for their analysis through direct observation, while hoping to contribute to making these remains more visible and to facilitate and promote their study. This methodological proposal can be applicable to materials of different composition and from very different contexts, chronologies, and origins.

Introduction. The fruit types such as raspberries (Rubus idaeus), cherries (Prunus cerasus), blackberries (Rubus fructicosus), blackthorns (Prunus spinosa) and aronia (Aronia melanocarpa) are very common in Serbia. These fruit species are a valuable source of antioxidants. The goal of our work was to evaluate the antioxidant activities of ethyl acetate extracts of these five berries and to establish possible correlation between the content of anthocyanin and the antioxidant activity. Materials and methods. To determine antioxidant activity of the selected fruits, the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, the ABTS (2,2-azinobis-3 ethyl benzothiazoline-6-sulfonic acid) cation decolorization activity, the FRAP (ferric reducing antioxidant power), and the TRP (total reducing power) were measured. Results. The four methods selected for our assays showed strong antioxidant properties for blackberry samples. The total anthocyanin content was estimated using the pH differential method. The highest amount of anthocyanin was found in blackberry samples [(1063.53 ± 0.01) mg·kg–1 fresh fruit], while the lowest was in raspberry samples [(180.84 ± 0.02) mg·kg–1 fresh fruit]. The correlation between the content of anthocyanin and antioxidant activity was established using regression analysis. The highest correlation was found between total reducing power and total anthocyanin (r = 0.97, p < 0.05). Hierarchical cluster analysis divided selected fruit species into two statistically significant clusters. Conclusion. Our results confirmed that analyzed berries are rich in anthocyanins. A strong correlation among different assays as well as with anthocyanin content was observed. Cluster analysis can be used in food science, to classify different food types into groups, based on similarity among the results.