Ultrasound-Assisted Extraction of Protein from Pumpkin Seed Press Cake: Impact on Protein Yield and Techno-Functionality

Abstract

Conventional solvent-based methods widely used for isolating plant proteins may deliver an unsatisfactory protein yield and/or result in protein degradation. The present study started with the optimization of pumpkin seed protein from press cake by alkaline extraction and subsequent isoelectric precipitation. Subsequently, extraction was supported by ultrasound under three conditions: ultrasonic treatment followed by alkaline extraction (US+AE), concomitant ultrasonic treatment and alkaline extraction (UAE), and alkaline extraction followed by ultrasonic treatment (AE+US). Compared to the control group, an increase in protein yield was achieved after ultrasonic treatment, while the highest protein yield was obtained with AE+US (57.8 ± 2.0%). Isolates with a protein content of 94.04 ± 0.77 g/100 g and a yield of 43.6 ± 0.97% were obtained under optimized conditions. Following ultrasonic treatment applied during extraction, solubility, foaming capacity, foam stability, and denaturation enthalpy of the isolated protein increased, and water binding capacity decreased as compared to non-sonicated samples. The d90 particle size percentile of the extracted suspensions was 376.68 ± 38.32 µm for the control experiments, and particle size was significantly reduced in ultrasound-assisted treatments down to d90 = 179.93 ± 13.24 µm for the AE+US treatment). Generally, ultrasonication resulted in a significant increase in protein yield and improved techno-functional properties of the isolates.

High‐pressure‐assisted protein isolation from pumpkin seed press cake

“…The isolated pumpkin seed protein has a molecular mass of around 35 kDa (Sert et al ., 2022). HPH treatment had no significant impact on the electrophoresis patterns compared to the control procedure, so that is ensured that HPH up to 150 MPa did not affect the protein's primary structure (Fig.…”

“…The control procedure was carried out under conditions previously established by Sert et al . (2022). Dispersions of press cake in deionised water (solvent‐to‐solid ratio of 29) were adjusted to pH 11.0 with 0.5 N NaOH and then stirred for 1 h at 500 rpm on a magnetic stirrer.…”

“…Although there are many studies on protein isolation from various plant sources, information related to pumpkin press cake is scarce (Bučko et al ., 2016; Vinayashree & Vasu, 2021; Du et al ., 2022; Sert et al ., 2022). The present study utilised HPH to increase the extraction efficiency of protein from the press cake of cold‐pressed pumpkin oil production.…”

Optimization of ultrasound-assisted cellulase degradation method on the extraction of mulberry leaf protein and its effect on the functional characteristics

“…Then the PDA of mulberry leaf gradually tends to maintain stability. The reason for this phenomenon was that the alkaline condition could increase the protein solubility, but it also could inactive cellulose, which led to an appropriate pH value of 7 [28] .

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Mechanism of ultrasonic combined with different fields on protein complex system and its effect on its functional characteristics and application: A review

“…Such as improving the extraction efficiency of raw materials, improving the success rate and possibility of compounding various raw materials, and the development and promotion of new protein-based products. Sert et al [88] abandoned the traditional solvent-based extraction method and used ultrasonic-assisted extraction when extracting pumpkin seed protein, the results showed that ultrasonic treatment could significantly increase the protein yield of isolates. Aarcha and Akalya [89] developed a new plant-based functional beverage and extended its shelf life to 14 days by ultrasound.…”