Biological activities, chromatographic profile and thermal stability of organic and conventional goji berry

Abstract

Goji fruits grown in the organic and conventional systems were investigated for phenolic content (TPC), antioxidant activity (AA), carotenoid and ascorbic acid profile, fatty acid composition (FA), and thermal stability. Phenolic extracts and solid samples were analyzed, comparing the use of shaker and ultrasound for Folin-Ciocalteu, Fast Blue BB, and FRAP methods. HPLC and GC-FID were used to determine the profile of carotenoids, ascorbic acid and FA, and oil thermal stability was determined by TG-DTG. Ultrasound showed a higher content of TPC and AA in organic (803.34–7076.43 mg GAE/100 g, 11.45–234.11 mmol TE/100 g) and conventional (763.01–6366.30 mg GAE/100 g, 10.27–117.12 mmol TE/100 g) samples in relation to the shaker. The Folin-Ciocalteu showed higher values (912.42–6350.54 mg/100 g) than the Fast-Blue BB method. The content of TPC and AA were 3–20 times higher in solid samples (Quencher) compared to extracts. (all-E)-lutein and (all-E)-zeaxanthin were the main carotenoids identified. Organic and conventional fruits showed a high vitamin C content (101.83 and 80.46 mg/100 g). Linoleic acid was the main FA, and the ω-6/ω-3 ratio was 0.13 and 0.12. Thermal decomposition for organic and conventional oils started at 130 and 170 °C, respectively. Organic fruits had a higher TPC, AA, (all-E)-zeaxanthin, vitamin C, and linoleic acid than conventional fruits. The results presented in this work show the potential of goji fruits, mainly cultivated in the organic system, as antioxidants and natural functional ingredients. Therefore, goji berry can be considered a food and a promising functional ingredient for developing products in different industrial segments with cosmetic, food, and pharmaceutical purposes.