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Effect of calcium chloride on mechanical properties and microbiological characteristics of cv. Conservolea naturally black olives fermented at different sodium chloride levels
Author(s) -
Tassou Chrysoula C,
Katsaboxakis Constantinos Z,
Georget Dominique MR,
Parker Mary L,
Waldron Keith W,
Smith Andrew C,
Panagou Efstathios Z
Publication year - 2007
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2823
Subject(s) - brine , lactic acid , chemistry , sodium , fermentation , calcium , food science , lactic acid fermentation , breakage , chloride , bacteria , biology , materials science , organic chemistry , genetics , composite material
The effect of calcium chloride (CaCl 2 )(5 gL −1 ) and sodium chloride (NaCl) concentration (40, 60 and 8 gL −1 ) on the microbiological and mechanical properties of naturally black olives of cv. Conservolea in brines was studied. In 40 and 60 g L −1 brines the growth of lactic acid bacteria was favoured over that of yeasts, resulting in rather complete lactic acid fermentation as indicated by high free acidity (9.8–11.5 g lactic acid L −1 ) and low pH (3.7–3.8). At 80 g L −1 brine, yeasts were the dominant members of the microflora, rendering a product with lower acidity (8 g lactic acid L −1 ) and higher pH (4.3–4.5). In the presence of CaCl 2 there was a consistent increase in the depth of the peripheral region in which cell wall breakage occurred. When cells separated, perforated walls were observed at sites associated with plasmodesmata. The flesh was strongest and stiffest when CaCl 2 was added to olives treated with 40 g L −1 brine, consistent with cell wall breakage being the predominant mode of failure. The only observed effect on the mechanical properties of the skin was a stiffening at 60 g L −1 brine on addition of CaCl 2 . Copyright © 2007 Society of Chemical Industry