Natural pigments (anthocyanins and chlorophyll) and antioxidants profiling of European red and green gooseberry (Ribes uva-crispa L.) extracted using green techniques (UAE-citric acid-mediated extraction)

Green techniques to extract natural pigments are gaining prominence among consumers and food industries. This trend is predominantly due to the harmful effects imparted by commonly used synthetic dyes and the unwarranted stress created on our ecosystem. The objectives of this study were to obtain natural pigments (anthocyanins and chlorophyll) from Estonian-gown European green and red gooseberries by ultrasonic-assisted citric acid-mediated extraction method and perform antioxidant profiling (quantification via HPLC analysis). Green gooseberry extracts showed lower content of targeted compounds, with low concentrations of rutin (0.7-1.2 mg/ L) and quercetin 3-glucoside (0.9-1.3 mg/L), while in the red gooseberry extracts, the amount was slightly higher (1.4-6.9 and 1.0-1.3 mg/L, respectively) with 0.6-6.8 mg/L cyanidin 3-glucoside and 0.32-0.35 mg/L peonidin 3 glucoside recorded. Further, the yield of anthocyanins ranged between 1.14-1.79 and 1.86-3.63 mg/100 g in green and red gooseberries, respectively. Total phenols ranged between 162-392 and 263-987 mg GAE/100 g in green and red gooseberry extracts, respectively. The DPPH free radicals scavenging activity showed 73-86% and 87-91% inhibition in both green and red gooseberry, respectively. Results showed significant improvements in pigment extraction with higher values obtained for targeted antioxidant compounds using conventional and UAE extraction (aqueous extract), thus confirming that green extractions are a reliable technique to obtain pigments of interest from natural sources. The results support consumers' demand and open up the avenue to explore pigments as natural colourants in food and cosmetics applications.