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Colour evaluation of a phycobiliprotein‐rich extract obtained from Nostoc PCC9205 in acidic solutions and yogurt
Author(s) -
Moreira Isabela de O,
Passos Thaís S,
Chiapinni Claudete,
Silveira Gabrielle K,
Souza Joana CM,
CocaVellarde Luis Guillermo,
Deliza Rosires,
de Lima Araújo Kátia G
Publication year - 2012
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.4614
Subject(s) - phycobiliprotein , nostoc , food science , cyanobacteria , chemistry , biology , bacteria , genetics
BACKGROUND: Phycobiliproteins are coloured proteins produced by cyanobacteria, which have several applications because of their colour properties. However, there is no available information about the colour stability of phycobiliproteins from Nostoc sp. in food systems. The aim of this work was to study the colour stability of a purple‐coloured phycobiliprotein‐rich extract from the cyanobacterium Nostoc PCC9205 in acidic solutions and yogurt. RESULTS: Variations of pH for Nostoc PCC9205 extract have shown stability for the L * (lightness) and a * (redness) indexes in the range 1.0–7.0. The b * index (blueness), however, increased at pH values below 4.0, indicating loss of the blue colour. The Nostoc PCC9205 extract was used as colorant in yogurt (pH 4.17) stored for 60 days. Instrumental colour analysis showed no changes for the L * and a * indexes during storage, whereas the b * index changed after 20 days of storage. A multiple comparison test showed colour instability after 20 days of storage. A hedonic scale test performed on the 60th day of storage showed acceptability of the product. CONCLUSIONS: The red component of the phycobiliprotein‐rich extract from Nostoc PCC9205 presented an improved stability in acidic media and yogurt compared with the blue component of this extract. Copyright © 2011 Society of Chemical Industry