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GREEN COLOR DEGRADATION of BLANCHED BROCCOLI ( BRASSICA OLERACEA ) DUE to ACID and MICROBIAL GROWTH
Author(s) -
GUNAWAN MARIA I.,
BARRINGER SHERYL A.
Publication year - 2000
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.2000.tb00417.x
Subject(s) - brassica oleracea , chemistry , pheophytin , degradation (telecommunications) , food science , chlorophyll , high performance liquid chromatography , benzene , botany , chromatography , photosynthesis , organic chemistry , biochemistry , biology , telecommunications , photosystem ii , computer science
Effect of acid and microbial growth on green color degradation of blanched broccoli (Brassica oleracea) during storage at 7C was studied. When broccoli was submerged in McIlvaine's buffer at pH 3–8, color degradation accelerated as pH decreased, as expected. High Performance Liquid Chromatography (HPLC) was used to show that the color degradation was due to the conversion of chlorophyll to pheophytin only. Pheophytinization followed a first order reaction. the logarithm of the reaction rate constants were linearly correlated to the environmental pH, up to pH 7. Acids containing a benzene ring caused a faster color change than acids with a simple carbon chain due to their hydrophobicity. Microbial growth accelerated color change by producing acid and produced what appear to be holes in the surface of the broccoli, as shown by Environmental Scanning Electron Microscopy (ESEM).