Effect of a physical pre-treatment and drying on carotenoids of goji berries (Lycium barbarum L.)

• Published in: Food science & technology 2018-06, Vol.92, p.318-323
• Main Authors: Fratianni, A., Niro, S., Alam, M.D.R., Cinquanta, L., Di Matteo, M., Adiletta, G., Panfili, G.
• Format: Article
• Language: English
• Subjects: Abrasive pre-treatment; Colour; Lycium barbarum L; Thermal treatment; Zeaxanthin-dipalmitate
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2018.02.048

In order to evaluate the influence of an abrasive pre-treatment and drying at 50 °C, 60 °C, 70 °C of goji fruits (Lycium barbarum L.), changes in colour and carotenoids were studied. An extraction method was modified and adapted to assay the main carotenoid esters and saponified carotenoids of goji berries, before and after treatments. Goji berries were confirmed as a high source of zeaxanthin, with zeaxanthin-dipalmitate at about 2 g/kg dry weight. The reliability of the analytical method was confirmed by the high quantitative recoveries, about 100%, a higher repeatability than reference methods and a good reproducibility (lower than 5%). After drying, significant but small carotenoid losses (15–20%) were observed in both pre-treated and treated samples. The xanthophyll esters confirmed to be more stable than free carotenoids. The drying process significantly modified colour, in both pre-treated and untreated samples, however, pre-treatment reduced drying time and thus better preserved the colour of the goji berries for a drying temperature up to 60 °C. •An extraction method was successfully modified to assay esters and saponified carotenoids.•Goji berries are confirmed as a high source of zeaxanthin, as zeaxanthin-dipalmitate.•Xanthophyll esters are confirmed to be more stable than free carotenoids.•Pre-treatment was effective in reducing drying time, preserving colour.•Pre-treatment and drying at 60 °C were the best technological conditions.