| Popis: |
The possibility of proving tha authenticity of the apricot nectars has been investigated by using the phenolic compounds fingerprint. The phenolic composition of the fresh material (two varieties of apricot and oumpkin), their purees and apricot nectars (with and without adding of definite shares of pumpkin puree) prepared under laboratory conditions, and those excluded from the local marcet has been determined by the high performance liquid chromatography (HPLC) with the UV Diode Array detection. Two different extraction methods were needed for the phenolic separation, one of them for flavonols and another for phenolic acids, flavan-3-ols, flavonol glycoside and related compounds. Analyses showed that in both varieties of apricot a lot of phenolic compounds have been determined (quercetin, kaempferol, chlorogenic acid, caffeic acid, p-coumaric acid, (+)-catechin, (-)-epicatechin, rutin, procyanidins) and in both varieties of pumpkin only the chlorogenic acid and syringic acid. Syringic acid is the compound characteristic for pumpkin and it was identified accoding to UV and IR spectra and polarity. Therefore, the pumpkin admixture of even lower levels (5%) in the apricot nectars could be proven by using the syringic acid. The cheaper pumpkin admixtures in apricot nectars could not be assumed by the sensory evaluation, particularly if present in quantities lowere than 15%. |
