Enzymatic hydrolysis of sunflower lecithins using a microbial PLA2

Abstract

Sunflower (Helianthus annuus L.) has an extremely favorable agro-ecological environment for cultivation in Argentina. In this country, the whole harvest for oil production is considered as non-GMO. Sunflower lecithins are obtained by gum purification from raw oil in a degumming process, which is part of the refining process of raw vegetable oils. Food industry uses lecithins because of their multifunctional ingredients. Modification processes of the original phospholipid composition of native lecithin, such as enzymatic hydrolysis, are appropriate for certain applications. The enzymatic activity of a microbial PLA2 (phospholipase A2) on the major phospholipids (PC, PE, PI) of sunflower lecithin, and the effect of processing conditions (PLA2 concentration of 0.4, 2.0 ml/100 g lecithin, without or with the addition of CaCl2 0.4 M, pH 7-9 for 40-300 min) were studied. Phospholipid composition of the sunflower lysolecithins using 31P NMR and the degree of enzymatic hydrolysis associated with each phospholipid (%HPL) were determined. The influence of the operating conditions on the enzymatic hidrolysis was analyzed by the evolution of the lysophospholipid content (LPL) and LPL/total phospholipid percent (LPL/PLT%) using a response surface methodology (RSM). The results showed that the different hydrolyzed sunflower lecithins presented a high LPL concentration, with respect to native lecithins (LPL ≈ 1.1%), demonstrating the efficiency of the process. In particular, the concentration of PLA2 presented a strong influence on the hydrolysis. Different operating conditions allowed obtaining modified lecithins with a wide range of LPL/PLT% values (11.17-57.48%). Furthermore, the use of a microbial phospholipase gives the possibility of generating a spectrum of sunflower lecithins with different phospholipid composition, which functionality as bioactive agents could be applied to the development of foods with kosher and halal certification.