Ultrasound-assisted extraction of phenolics from wine lees: Modeling, optimization and stability of extracts during storage

Abstract

The ultrasound-assisted extraction process of phenolics including anthocyanins from wine lees was modeled and optimized in this research. An ultrasound bath system with the frequency of 40 kHz was used and the acoustic energy density during extraction was identified to 48 W/L. The effects of extraction time, extraction temperature, solvent-to-solid ratio and the solvent composition on the extraction yields of total phenolics and total anthocyanins were taken into account. The extraction process was simulated and optimized by means of artificial neural network (ANN) and genetic algorithm (GA). The constructed ANN models were accurate to predict the extraction yields of both total phenolics and total anthocyanins according to the statistical analysis. Meanwhile, the input space of the ANN models was optimized by GA, so as to maximize the extraction yields. Under the optimal conditions, the experimental yields of total phenolics and total anthocyanins were 58.76 and 6.69 mg/g, respectively, which agreed with the predicted values. Furthermore, more amounts of total phenolics and total anthocyanins were extracted by ultrasound at the optimal conditions than by conventional maceration. On the other hand, the stability of phenolics in the liquid extracts obtained from ultrasound-assisted extraction during storage was evaluated. After 30-day storage, the total phenolic contents in extracts stored at 4 °C and 20 °C decreased by 12.5% and 12.1%, respectively. Moreover, anthocyanins were more stable at 4 °C while tartaric esters and flavonols exhibited a better stability at 20 °C. Overall, the loss of phenolics during storage found in this study could be acceptable.

Ultrasound Assisted Extraction for the Recovery of Phenolic Compounds from Vegetable Sources

“…The first is called the "washing" step, which covers the first 10-20 min of extraction. In this step the dissolution of the soluble components on the surfaces of the matrix is carried out and it is at this stage that up to 90% of the recovery of the total content of the phenolic compounds can be achieved thus indicating a considerably rapid extraction rate [45]. In the second stage, known as "slow extraction", the mass transfer of the solute from the matrix into the solvent is carried out by diffusion; the time of this process can last from 60 to 100 min [37].…”

Comparison of Conventional and Ultrasound Assisted Supercritical Carbon Dioxide Extraction of Curcumin from Turmeric (Curcuma longa L.)

“…However, when higher temperature was applied in extraction, extraction yield and curcumin content in extract may decrease because temperature might be continue to increase by the high intensity of ultrasound. Also, the oxidation of some compounds may occur due to the small amount of moisture content in material [21,22]. Moreover, increasing temperature increased the volatility and diffusion of the solute and reduced the density of CO2.…”

Optimization of ultrasound-assisted extraction of phenolic compounds, antioxidants and rosmarinic acid from perilla leaves using response surface methodology

“…Several studies have reported that extracts of perilla leaves have high antioxidant capacity, mostly due to the presence of polyphenolic compounds (Lee et al, 2013;Zhou et al, 2014). Phenolic compounds are well-known for their beneficial health properties, attributed to their antioxidant and antiradical activities (Tao et al, 2014;Krishnaswamy et al, 2013;Heim et al, 2002). Moreover, rosmarinic acid (RA) has been shown to be the main biologically active polyphenolic compound in perilla leaves (Liu et al, 2013).…”

“…Of these methods, ultrasound-assisted extraction (UAE) technology has gained increasing popularity due to its advantageous properties, including high extraction efficiency, good reproducibility, low solvent consumption, speed, low cost, environmental friendliness and easy scale up for industrial applications (Tao et al, 2014;Cravotto et al, 2008;Vinatoru, 2001;Vuong et al, 2014). The enhancement of extraction using ultrasound is mainly attributed to acoustic cavitations produced in the solvent (Ma et al, 2008;Velickovic et al, 2008), and ultrasound technology has been used to improve different food processes (Kiani & Sun, 2011;Kiani et al, 2012) in addition to extraction.…”