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Polyphenol oxidase activity in white tan‐plant‐type sorghums: An important determinant of the relatively dark colour of their porridges
Author(s) -
Hikeezi Doreen M.,
Duodu Kwaku G.,
Chisi Medson,
Rooney Lloyd W.,
Taylor John R.N.
Publication year - 2013
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.12045
Subject(s) - sorghum , cultivar , polyphenol oxidase , food science , biology , sorghum bicolor , polyphenol , horticulture , white (mutation) , plant breeding , agronomy , botany , enzyme , biochemistry , peroxidase , antioxidant , gene
Summary The relatively dark colour of food products from white tan‐plant (food‐grade) sorghums can compromise their acceptability. The relationship between white tan‐plant sorghum polyphenol oxidase activity ( PPO ) and porridge colour was investigated, primarily using lines grown in the same locality over two seasons. Sorghum was intermediate in PPO between wheat and maize. White tan‐plant sorghum and white maize whole grain flours were similar in colour. However, with white tan‐plant sorghum, the transition from flour to porridge caused a much larger reduction in L* value. Further, the correlation between white tan‐plant sorghum PPO activity and porridge L* values was highly significantly negative ( P < 0.001), the relationship accounting for 40–50% of variation. PPO in white tan‐plant‐type sorghums is therefore an important determinant of the relatively dark colour of porridges. Breeding to reduce PPO activity could improve consumer appeal. Cultivar Sima ( IS 23520) that had low PPO activity and produced light‐coloured porridge could be useful for breeding.