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Effect of lyophilisation, refrigerated storage and frozen storage on the coagulant activity and microbiological quality of Cynara cardunculus L. extracts
Author(s) -
Tejada Luis,
Vioque Montserrat,
Gómez Rafael,
FernándezSalguero José
Publication year - 2008
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.3193
Subject(s) - chemistry , food science , mesophile , lactic acid , cold storage , bacteria , biology , horticulture , genetics
BACKGROUND: Cheese‐makers have traditionally kept vegetable coagulants refrigerated until use, even though little was known of their microbiological quality or coagulant activity during storage. This study aimed to assess the efficacy of lyophilisation, refrigerated storage and frozen storage of fresh vegetable extract as a means of standardising coagulant activity in terms of coagulation times, pH and microbiological quality. RESULTS: Neither the pH nor the coagulation time of lyophilised extracts was significantly modified during 1 year; however, changes were observed following frozen storage, and more notable following refrigerated storage. Lyophilisation of aqueous extracts prompted the destruction of most micro‐organisms; low counts initially noted for total mesophiles, lactic acid bacteria and yeasts disappeared during the first few days of storage, due to low water activity. There was a generalised decrease in micro‐organism counts during frozen storage. Refrigeration was found to be unsuitable for storing of cardoon extract; an increase of roughly 2 log unit counts was recorded in total mesophile, lactic acid bacteria, yeast and mould counts after 1 year of refrigerated storage. CONCLUSION: Refrigerated storage cannot be considered a suitable method for prolonged conservation of aqueous cardoon extract. Both lyophilisation and frozen storage of aqueous extracts proved ideal for prolonged storage of vegetable coagulant. Lyophilisation additionally had certain advantages over frozen storage. Copyright © 2008 Society of Chemical Industry