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Chayote leaves are known for culinary and traditional medicine applications. This work intended to recover carotenoids and phenolic compounds from chayote leaves using the ultrasound-assisted extraction (UAE). A Box–Behnken design was employed to investigate the impact of extraction time, temperature, and ultrasonic power on the recovery of total carotenoids, total phenolic compounds, and antioxidant activities. For comparative purposes, chayote leaf extracts were prepared by maceration (ME) and microwave-assisted extraction (MAE), using the same time and temperature conditions optimized by UAE. Extraction at 50 °C and 170 Watts for 30 min provided the optimal UAE conditions. UAE showed better extraction efficacy than ME and MAE. The HPLC analysis of the extracts showed that the xanthophyll class was the main class of carotenoids, which constituted 42–85% of the total carotenoid content, followed by β-carotene and tocopherol. Moreover, 26 compounds, classified as phenolic acids, flavonols, flavonoids and other polar compounds, were identified in the chayote leaf extracts. Flavonols accounted for 55% of the total compounds quantified (the major compound was myricetin) and phenolic acids represented around 35%, mostly represented by ferulic acid, chlorogenic acid and (+)-catechin. This study revealed the potential of UAE as an effective green extraction technique to recover bioactive compounds from chayote leaves, for food, and for pharmaceutical and cosmetic applications. [ABSTRACT FROM AUTHOR]

Rhodophyta represents the largest seaweed phylum including a wide variety of species, such as Chondrus crispus Stackhouse, with benefits for consumers health due to their nutritional value and bioactive compounds. This work aimed to optimize the extraction of compounds from C. crispus using a three-step optimization process. The first step consisted in pigment extraction using ultrasound-assisted extraction; the performance of an ultrasonic probe (20 kHz, 750 W) and a bath (40 kHz, 120 W) for 20 or 40 min was compared. The second step corresponded to protein extraction and the third step was the carrageenan formation. Step 1 extracts contained two carotenoids (fucoxanthin and lutein), 5 chlorophyll- a derivatives and pheophythin- a , phenolic compounds and revealed moderate antiradical activity against DPPH•, ABTS•+ and O 2 •-, but no activity against •NO and cholinesterases. Proteins and carrageenan's yields were between 3.6 and 41 g/100 g and 29.7–36.1 g/100 g, respectively. Considering all the performed analyses, the use of ultrasonic bath (40 kHz, 120 W) for 40 min is efficient to extract valuable compounds from C. crispus , which is advantageous from an economic point of view and therefore more attractive for industrial purposes. The obtained extracts may find possible future application in human diet or as additives for pharmaceutic and cosmetic industry. • C. crispus bioactive compounds were extracted by a three-step optimization process. • Pigment extract revealed moderate antiradical activity against DPPH.•, ABTS•+ and O 2 •- • Pigment extract had no activity against.•NO and cholinesterases • Proteins and carrageenans yields were between 3.6% - 41% and 29.7%–36.1%. • The ultrasonic bath (40 kHz, 120 W) for 40 min was the preferable approach. [ABSTRACT FROM AUTHOR]