Classification and prediction of ?-irradiation of ten commercial herbs and spices by multivariate evaluation of properties of their extracts
2013
Polovka, M., Food Research Institute, Bratislava (Slovak Republic) | Suhaj, M., Food Research Institute, Bratislava (Slovak Republic)
Antioxidant activity, dry matter content, extractability, total phenolic compounds content and CIE L*a*b* colour charac¬teristics of methanolic extracts of 10 spices exposed to ?-irradiation doses from 0 kGy (reference) to 30 kGy were evaluated in different time intervals after the irradiation by means of UV-VIS spectrophotometry in order to assess the influence of g-irradiation and post-irradiation storage on spices quality. Experimental data revealed that ?-irradiation itself did not cause so dramatic changes as the subsequent post-irradiation storage, or, that the changes were, at least, comparable. Multivariate statistical methods (factor analysis, canonical discriminant analysis and kth-nearest neighbour classification) facilitated differentiation of irradiated spices from the corresponding references and ?-radiation dose prediction on the basis of processing of experimentally determined characteristics of their extracts. In case of samples exposed to 0 kGy, 10 kGy and 30 kGy, differentiation and classification correctness higher than 85% was reached. In case of 0 kGy and 30 kGy samples differentiation, for 8 spices absolutely correct recognition was achieved and, for remaining 2 spices, still sufficient recognition correctness of 75% and 92.8%, respectively, was achieved. By the statistical models used, more than 90% correctness of dose prediction was achieved in the majority of cases.
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