Ba. Jones et al., SCREENING LEGUME FORAGES FOR SOLUBLE PHENOLS, POLYPHENOL OXIDASE AND EXTRACT BROWNING, Journal of the Science of Food and Agriculture, 67(1), 1995, pp. 109-112
Red clover (Trifolium pratense) is a legume that will brown quickly up
on harvesting. This browning of red clover has been correlated to a re
duction in proteolysis and requires the presence of a polyphenol oxida
se and soluble phenol substrates. A method was developed to screen for
ages for soluble phenols, soluble polyphenol oxidase activity and extr
act browning. Fourteen different legumes and 24 red clovers (22 plant
introductions and two cultivars), field grown in replicated plots, wer
e screened. Of the different legumes, only red clover had measurable s
oluble polyphenol oxidase activity (7.70 abs g(-1) leaf) and underwent
browning (0.245 abs g(-1) leaf). This extract browning and polyphenol
oxidase activity were present in all red clovers tested and ranged fr
om 0.153 to 0.458 and 6.00 to 9.00 abs g(-1) leaf, respectively. All o
f the legumes, including all red clovers, gave a positive response for
soluble phenols.