TOMAS Mabel Cristina
capítulos de libros
Emulsifying properties of hydrolyzed sunflower lecithins by phospholipases A2 of different sources
The Food Industry Book 2
Lugar: Rijeka; Año: 2012; p. 39 - 50
Lecithins are a mixture of acetone insoluble phospholipids, containing mainly phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), minor compounds such as phosphatidic acid (PA), and other minor substances such as carbohydrates and triglycerides (Schneider,1989). The production of sunflower oil, in Argentina, is of utmost importance from an economic point of view (Franco, 2008). In this country, sunflower lecithin might represent an alternative to soybean lecithin because it is considered a non-GMO product, which is in accordance with the preference of some consumers. The introduction of changes in the original concentration of these phospholipids, by chemical or enzymatic modification of their structure can lead to obtain lecithins with different physicochemical and functional properties, with respect to native lecithin (van Nieuwenhuyzen & Tomás, 2008). The modification processes usually applied on native 28 lecithins are the fractionation with ethanol (Sosada, 1993; Wu & Wang, 2004; Cabezas et al., 29 2009a, 2009b) and the enzymatic hydrolysis (Schmitt & Heirman, 2007; Cabezas et al.,2011a). Native and modified lecithins are used in a wide range of industrial applications: nutritional, pharmaceutical applications, food, cosmetics, etc. (Prosise, 1985; Wendel, 2000). In the food industry, lecithin represents a multifunctional additive in the manufacture of chocolate, bakery and instant products, margarines, and mayonnaise, due to the characteristics of its phospholipids (van Nieuwenhuyzen, 1981). In particular, enzymatic hydrolyzed lecithin may present technological and commercial advantages over native lecithins: (1) enhanced O/W emulsifying property; (2) increased emulsion stability under acid conditions and in the coexistence with salts; (3) improved capability to bind proteins and starch; (4) excellent mold- or pan-1 releasing property. Consequently, the demand for lysolecithins was increasing in recent years (Hirai et al., 1998; Erickson, 2008). The main application of lecithin at the food industry is associated with its rol as emulsifier agent for dispersions or emulsions (Hernández & Quezada, 2008). Emulsions are thermodynamically unstable systems from a physicochemical point of view. In virtue of that, it is important to characterize and know their behaviour against different destabilization processes (flocculation, coalescence, creaming, etc.) (McClements, 1999). Enzymatic hydrolysis is carried out mainly by two groups of enzymes: phospholipases and lipases (Mustranta et al., 1995). Phospholipases A2 catalyze the hydrolysis of the ester bond in the sn-2 position of glycerophospholipids, producing free fatty acids and the corresponding lysophospholipid. Advances in biotechnology and certain requirements of consumers (kosher or halal foods) have influenced the development of the production of microbial enzymes (bacteria, fungi, yeasts) which could be substitute of the traditionally obtained from porcine pancreas (Minchiotti, 2006; Cabezas et al., 2011b). The aim of this work was analyze the emulsifying activity of sunflower lysolecithins obtained by phospholipases A2 from diverse sources: bacterial (LysoMax PLA2, Danisco)and porcine pancreas (Lecitase 10L, Novo Nordisk) in O/W systems. This study seeks to contribute to the oil industry with useful information for rescaling of the mentioned hydrolysis process, with the aim of increasing the aggregated value of sunflower lecithins.