Evaluation of tissue dissociation of durum wheat grain (Triticum durum Desf.) generated by the milling process

Abstract

The three major botanical components (starchy endosperm, aleurone layer and pericarp) of eight durum wheat samples exhibited significantly different compositions and concentrations in phenolic acids. The starchy endosperm, the aleurone layer and the pericarp were respectively characterised by a low content in ferulic acid (FA), a high content in trans-sinapic acid (t-SA), and a high content in ferulic acid dehydrodimers (DHD). These three chemical markers can be exploited to differentiate the three grain botanical parts within milling fractions and to evaluate the milling efficiency, particularly the separation between bran and endosperm. The histological dissociation of the wheat grain generated by the milling process can be investigated further into details using the three phenolic acids markers. A separability index (Si) was proposed in order to quantify the ease of dissociation of endosperm from bran. Differences in Si values between wheat varieties grown under various agricultural conditions demonstrated the relevant variability of this character. The structural and molecular factors implied in the control of tissue dissociation are discussed in details. © 2002 Elsevier Science Ltd. All rights reserved.