Enzyme and Ultrasound Pretreatments to Improve Extraction of Carotenoids from Industrial Carrot Waste

In an attempt to enhance the upcycling potential of industrial fruit juice waste streams, beta-carotene-enriched carotenoid extraction from carrot pomace has been applied. Both enzyme and ultrasound pretreatments improved the extraction efficiency. Among them, enzymatic pretreatment with pectinase was found to be the most effective, which increased total flavonoid content and antioxidant activity by 2-fold while increasing beta-carotene and total phenolic content by 5-fold compared to conventional solvent extraction. The alpha- and beta-carotene contents of the enzyme pretreated extract were found to be 8.6 and 32.5 mg/100 g of dry weight, respectively. All pretreatments improved the antimicrobial activity of the extracts. The minimum bactericidal concentration of the enzyme pretreated extract was recorded as 8 and 16 mg/mL against Escherichia coli and Salmonella typhimurium, respectively, which was 8 and 4 times more effective than the conventionally extracted one, respectively. The carotenoid-rich extracts obtained are promising value-added ingredients for the improvement of the nutritional value, bioactivity, and shelf life of foods.