An ultrasound-assisted method was used for the extraction of phenolics from defatted black cumin seeds (Nigella sativa L.), and the effects of several extraction factors on the total phenolic content and DPPH radical scavenging activity were investigated. To improve the extraction efficiency of phenolics from black cumin seed by ultrasonic-assisted extraction, the optimal extraction conditions were determined as follows: ethanol concentration of 59.1%, extraction temperature of 44.6 °C and extraction time of 32.5 min. Under these conditions, the total phenolic content and DPPH radical scavenging activity increased by about 70% and 38%, respectively, compared with conventional extraction. Furthermore, a complementary quantitative analysis of individual phenolic compounds was carried out using the HPLC-UV technique. The phenolic composition revealed high amounts of epicatechin (1.88–2.37 mg/g) and rutin (0.96–1.21 mg/g) in the black cumin seed extracts. Ultrasonic-assisted extraction can be a useful extraction method for the recovery of polyphenols from defatted black cumin seeds.

Plant-based proteins are gaining in attraction compared with animal-based proteins due to their superior ethical profiles, growing concerns on the part of various organizations about animal health and welfare, and increased global greenhouse-gas emissions in meat production. In this study, the response surface methodology (RSM) using a Box–Behnken design (BBD) was applied to optimize the ultrasound-assisted alkaline extraction of cherimoya-seed proteins as valuable by-products. The effects of three pH, temperature, and time factors on the protein-extraction yield and protein content were investigated. The pH at 10.5 and temperature of 41.8 °C for 26.1 min were considered the optimal ultrasound-assisted alkaline-extraction conditions since they provided the maximum extraction yield (17.3%) and protein content (65.6%). An established extraction technique was employed to enhance the cherimoya-seed protein yield, purity, and functional properties. A thermogravimetric analysis (TGA) of the samples showed that the ultrasound-assisted alkaline extraction improved the thermal stability of the protein concentrate.