COLOR CHARACTERISTICS AND ENZYME ACTIVITY OF PEROXIDASE AND POL YPHENOLOXIDASE IN DIFFERENT WHEAT CULTIVARS AND THEIR PASTA: 	1- 	EFFECT 	OF 	MILLING 	PROCESS 	ON 	COLOR CHARACTERISTICS AND ENZYME ACTIVITY OF PEROXIDASE AND POL YPHENOLOXIDASE IN DIFFERENT WHEAT CUL TIVARS

Ramadan, M. T.; Eissa, H. A.; EI-Faham, S. Y.

doi:10.21608/jfds.2004.240575

COLOR CHARACTERISTICS AND ENZYME ACTIVITY OF PEROXIDASE AND POL YPHENOLOXIDASE IN DIFFERENT WHEAT CULTIVARS AND THEIR PASTA: 1- EFFECT OF MILLING PROCESS ON COLOR CHARACTERISTICS AND ENZYME ACTIVITY OF PEROXIDASE AND POL YPHENOLOXIDASE IN DIFFERENT WHEAT CUL TIVARS

Document Type : Original Article

Authors

Food Technology Dep. National Research Centre, Cairo, Egypt.

10.21608/jfds.2004.240575

Abstract

The activity of polyphenoloxidase (PPO) and peroxidase (POD) by milling
different durum and soft wheat cultivars was investigated. Also, non-enzymatic
browning and color characteristics were determined in milled different durum and soft
wheat wheat cultivars. Milling whole-grain into bran and semolina markedly decreased
POD and PPO activities in semolina fraction and increased in bran fraction. The
highest activity was found in bran fraction. The POD and PPO activities were much
higher both in bran fraction and whole kernel for all eight-wheat cultivars than of in
semolina fraction. The PPO activity in the bran fraction was three times higher than
that semolina fraction, and POD activity was six times greater. No difference in the
non-enzymatic browning recorded at 420nm was found between different wheat and
different wheat fractions. Results are obvious that milling process of wheat increased
the development of red colour parameter a>. The a'-values were in the range of (4.39-
6.09) in whole meal, decreased to (1.10-3.02) in semolina fraction and increased to
range (6.28-7.65) in bran fraction of different wheat cultivars respectively. The Hunter
colour values of semolina fraction of different wheat cultivars were lower than those of
bran fraction. Other color parameters such as Hue angle and chroma also indicated
that heat from milling process caused a slight color change. Results indicates that
whole meal, bran and semolina become yellow-green but was still reddish because
the hue angle was positive. The samples of bran fraction had a 81 value higher 6
times than those of the semolina fraction. But, 81 values of whole meal were lower
than those of the bran fraction and higher than in semolina fraction. Results
demonstrated that wheat cvs. without bran and/or with low in POD and PPO activities
would be suitable for pasta making

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