Optimization of the extraction conditions for antioxidant activities and phenolics of Auricularia auricula, an edible mushroom

Leong , Shan Mei (2013) Optimization of the extraction conditions for antioxidant activities and phenolics of Auricularia auricula, an edible mushroom. Universiti Malaysia Sabah. (Unpublished)

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Abstract

The study aimed to optimize the extraction conditions for natural antioxidants from Auricularia auricula, an edible mushroom. Single factor experiment was used to determine the significant factors that influenced yield, total phenolic content and antioxidant capacity indicated by antioxidant assays such as 2,2'-azino-bis (3- ethylbenzothiazoline-6-sulphonic acid) (ASTS), ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-pircryl-hydrazyl (OPPH) of the Auricularia auricula extract. Factors selected for the optimization of the extraction conditions were solvent concentration, extraction temperature and solid to solvent ratio. The optimization was carried out by a rotatable central composite design (CCD) under response surface methodology (RSM). The ranges of factor selected for the optimization process were 75-90% ethanol, 45-55°C, temperature and 1:10-1:20 solid to solvent ratio. These factors were coded into 5 levels consisting 8 factorial points, 6 axial points and 6 center points. The overall optimized conditions for the extraction of natural antioxidants from Auriularia auricula were solvent percentage of 81.69%, temperature of 49.48°C and solid to solvent ratio of 15.88. The optimized extract of Auricularia auricula has the highest value of TPC (17.78 mg GAE/g), FRAP (111.46 µM Fe²⁺/g), ABTS (8.81 µM TE/g), EC50 DPPH (0.904 mg/ml) and Oxygen Radical Absorbance Capacity (ORAC)(388.85 µM TE/g). Verification test indicated that most of the optimized responses are within the acceptable range of 5% from the predicted value. The optimized extract showed increment values in TPC (34.54%), extraction yield (23.77%) and FRAP (17.31%). Five phenolic compounds were detected in the ethanolic extract of Auricularia auricula namely gallic acid (1.27 µg/g), catechin (32.33 µg/g), chlorogenic acid (56.67 µg/g), p-coumaric acid (0.52 µg/g) and rosmarinic acid (2.26 µg/g). Most of these phenolic compounds have increased more than 50% in the optimized extract. As conclusion, the optimized condition could improve the extraction efficiency of natural antioxidant from Auricularia auricula and therefore could be potentially applied for pre-commercialization.

Item Type:Academic Exercise
Uncontrolled Keywords:extraction, antioxidant, Auricularia auricula, edible mushroom, response surface methodology (RSM)
Subjects:T Technology > TX Home economics > Nutrition. Foods and food supply
Divisions:SCHOOL > School of Food Science and Nutrition
ID Code:9818
Deposited By:IR Admin
Deposited On:28 Nov 2014 14:14
Last Modified:28 Nov 2014 14:14

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