Comparisons between conventional, microwave- and ultrasound-assisted methods for extraction of pectin from grapefruit

Abstract Microwave-assisted Extraction (MAE) and Ultrasound-assisted extraction (UAE) techniques have been employed as complementary methods to extract carbohydrates, polysaccharides and other functional compounds from vegetable sources. In this work, the effect of microwave power and heating time on the yield and quality of extracted pectin from grapefruit was investigated. The highest total amount of pectin yield was found to be 27.81% (w/w) for 6 min of extraction at 900 W. It was observed that yield, the galacturonic acid content (GalA), and degree of esterification (DE) increased with an increase in microwave power and heating time. Besides, the molecular weight decreased with an increase in heating time; however, the effects of power on the molecular weight were dramatically more than heating time. In addition, laboratory studies on the extraction of pectin treated with high-intensity ultrasound were carried out. The effects of temperature and time on quality and quantity of extracted pectin were investigated. The highest yield was for sonication time of 25 min (17.92%) in a constant bath temperature of 70 °C. Furthermore, a preliminary ultrasonic heating of grapefruit solution, as a pretreatment for MAE, was found to provide a higher yield. Intermittent sonication gave better results in comparison to the continuous sonication.

[1]  Hasan Toǧrul,et al.  Filtration of pectin extract from grapefruit peel and viscosity of pectin solutions , 1996 .

[2]  C. May,et al.  Industrial pectins: Sources, production and applications , 1990 .

[3]  Gustavo V. Barbosa-Cánovas,et al.  Extraction and characterization of pectin from stored peach pomace , 2001 .

[4]  T. Langrish,et al.  Comparisons between different techniques for water-based extraction of pectin from orange peels , 2008 .

[5]  Brant C. White,et al.  United States patent , 1985 .

[6]  J. Weiss,et al.  Ultrasonic processing influences rheological and optical properties of high-methoxyl pectin dispersions , 2003 .

[7]  J. Mikkelsen,et al.  Pectin: new insights into an old polymer are starting to gel , 2006 .

[8]  Xiaosong Hu,et al.  Optimization of pectin extraction assisted by microwave from apple pomace using response surface methodology , 2007 .

[9]  A. Ibarz,et al.  Improvement in the measurement of spectrophotometric data in the m-hydroxydiphenyl pectin determination methods , 2006 .

[10]  J. Kennedy,et al.  Image study of pectin extraction from orange skin assisted by microwave , 2006 .

[11]  Ivan Panchev,et al.  The effect of microwave heating of fresh orange peels on the fruit tissue and quality of extracted pectin , 2004 .

[12]  M. Fishman,et al.  Characterization of pectin, flash-extracted from orange albedo by microwave heating, under pressure. , 1999, Carbohydrate research.

[13]  Marshall L. Fishman,et al.  Microwave-assisted extraction of lime pectin $ , 2006 .

[14]  I. Panchev,et al.  Improving pectin technology. , 2007 .

[15]  M. Kratchanova,et al.  Extraction of pectin from fruit materials pretreated in an electromagnetic field of super-high frequency , 1994 .

[16]  Karel Grohmann,et al.  Hydrolysis of grapefruit peel waste with cellulase and pectinase enzymes. , 2007, Bioresource technology.

[17]  C. Leonelli,et al.  Microwave and ultrasonic processing: Now a realistic option for industry , 2010 .

[18]  Muthupandian Ashokkumar,et al.  Selected Applications of Ultrasonics in Food Processing , 2009 .

[19]  I. Panchev,et al.  On the production of low esterified pectins by acid maceration of pectic raw materials with ultrasound treatment , 1994 .

[20]  Alex Patist,et al.  Ultrasonic innovations in the food industry: From the laboratory to commercial production , 2008 .

[21]  Farzin Zokaee Ashtiani,et al.  The influence of acid volume, ethanol-to-extract ratio and acid-washing time on the yield of pectic substances extraction from peach pomace , 2008 .