Influence of applied drying methods on phytochemical composition in fresh and dried goji fruits by HPLC fingerprint

Lycium spp. fruit (goji or wolfberry) has become more popular due to its public acceptance as a functional food or "super food/fruit". The aim of this study was to describe the influence of two different drying systems (air-thermal and freeze drying) on fresh and dried goji fruit nutraceutical traits and report on the level of potentially bioactive compounds and their effects on total fruit phytocomplex and antioxidant activity. Spectrophotometric and chromatographic methods coupled to multivariate analysis were performed on all the goji samples. In this research, goji fresh and dried fruits were identified as a source of compounds with potential health-promoting properties. The results of this study showed that freeze drying allowed to preserve most of the phytochemical characteristics of the fresh fruits, as phenolic acids (ferulic and ellagic acids) and vitamin C content. Moreover, polyphenols could be selected as biomarkers in order to distinguish different Lycium species or the same Lycium genotype from different geographical areas. This research emphasizes that an adequate evaluation of nutraceutical traits is necessary in order to select the higher-quality raw materials (cultivated varieties): as a cost-effective and efficient way to trace food, this study showed that HPLC fingerprint can be used to identify and track different raw materials (fresh fruits) and derived food products (dried fruits).