Extraction optimization for antioxidant phenolic compounds in red grape jam using ultrasound with a response surface methodology

Abstract

Optimization of the extraction methodology for antioxidant phenolic compounds in red grape jam was performed with an ultrasound-assisted system. The antioxidant phenolic compounds were extracted and analyzed by determining the total phenolic content (Folin Ciocalteu), as well as by employing free radical DPPH() and the beta-carotene/linoleic acid system. To optimize the parameters of solvent concentration, time and extraction temperature, the experiments were carried out using the central composite rotatable design (CCRD) method. Using response surface methodology (RSM), the best combinations achieved were with 60% ethanol and water for 20min at 50°C. The optimized parameters for this method were compared to an extraction method that has been commonly noted in the literature, which used to be the standard method, and the results were expressed in the milligram equivalent of quercetin per gram of jam (mg E.Q/g Jam). With the new method, the antioxidant potential measured by DPPH(ⁱ) was 70% higher than that obtained with the standard extraction method, and the antioxidant potential measured using the beta-carotene/linoleic acid system was 65% higher. In addition, a significant decrease in the total analysis time was achieved (from 10h to 30min), when compared to the standard method.

Methanol to clean gasoline over nanostructured CuO–ZnO/HZSM-5 catalyst: Influence of conventional and ultrasound assisted co-impregnation synthesis on catalytic properties and performance

“…High temperature breaks the chemical bonds much faster and easier and causes the impregnation to proceed (Gogate et al, 2011). In addition, bubble collapsing occurs in less than a nano second and so, a high rate of temperature decrease (1000 K/S) takes place that leads to particle agglomeration prevention (Gouvêa et al, 2012;Morelli and Prado, 2012;Wang and Prasad, 2012). Furthermore, many investigations proved that the activity of the ultrasonic assisted catalysts retains its activity for longer times (Vafaeian et al, 2013).…”

Optimization of Ultrasound-Assisted Extraction Procedure to Determine Antioxidant Capacity of Rapeseed Cultivars

“…As can be seen, 50 % methanol was a better extraction solvent than 25 and 75 % methanol for preparation of rapeseed samples to determine their antioxidant capacity (Tables 1 and 2). Also, higher concentrations of ethanol (70 %) led to lower DPPH values of red grape jam extracts (1.83-2.57 mg E.Q/g jam) (Morelli and Prado 2012). On the other hand, the antioxidant capacity of the studied rapeseed cultivars increased when the solvent-to-solid ratio was increased from 15 to 30 mL/g.…”

“…Moreover, response surface methodology (RSM) was successfully applied for optimization of the UAE of antioxidants from different food products (Morelli and Prado 2012;Tabaraki et al 2012;Wang et al 2008).…”

Evaluation of antioxidant activity of loquat fruit (Eriobotrya japonica lindl.) skin and the feasibility of their application to improve the oxidative stability of soybean oil

“…β-carotene/linoleic acid assay Antiradical capacity of the extracts was measured according to method by Morelli and Prado (2012). One milligram of β-carotene, 200 mg of Tween 20, and 20 μl of linoleic acid were added to 5 ml of chloroform and placed in a roundbottom flask.…”