This study was carried out to evaluate the influence of the lipase-producing yeasts, present in the brine, on the quality of table olive oil. The oily fraction of olives processed microbiologically using the Beta-glucosidase-positive, lipase-negative yeast Candida wickerhamii 1542 showed an excellent quality, such as the typical extra-virgin olive oil. In contrast, the quality of the oily fraction of olives debittered microbiologically with the Beta-glucosidase- and lipase-producing yeast Williopsis californica 1639 worsened dramatically to such a point that the acidity of the oily fraction increased more than 90%. The microbiological analysis of brines showed that the lipase-producing yeasts are part of the natural yeast population of the brine, and when their presence is high, it can damage significantly the quality of table olives. The lipase-producing yeast W. californica 1639 in the brine showed the maximum lipolytic activity at pH 6, while the NaCl of the brine, at the maximum concentration of 12%, inhibited lipase activity by 70%. The concentration of the polyphenols present in the brine was not able to control the lipolytic activity of W. californica 1639 during the microbiological debittering process of table olives.

Effect of lipase-producing yeast on oily fraction of the table olive debittered microbiologically

CIAFARDINI, Gino;
2005-01-01

Abstract

This study was carried out to evaluate the influence of the lipase-producing yeasts, present in the brine, on the quality of table olive oil. The oily fraction of olives processed microbiologically using the Beta-glucosidase-positive, lipase-negative yeast Candida wickerhamii 1542 showed an excellent quality, such as the typical extra-virgin olive oil. In contrast, the quality of the oily fraction of olives debittered microbiologically with the Beta-glucosidase- and lipase-producing yeast Williopsis californica 1639 worsened dramatically to such a point that the acidity of the oily fraction increased more than 90%. The microbiological analysis of brines showed that the lipase-producing yeasts are part of the natural yeast population of the brine, and when their presence is high, it can damage significantly the quality of table olives. The lipase-producing yeast W. californica 1639 in the brine showed the maximum lipolytic activity at pH 6, while the NaCl of the brine, at the maximum concentration of 12%, inhibited lipase activity by 70%. The concentration of the polyphenols present in the brine was not able to control the lipolytic activity of W. californica 1639 during the microbiological debittering process of table olives.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11695/3089
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