Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as avonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p-coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were signi®cantly in¯uenced by the tomato variety. Quercetin, the most abundant¯avonoid, was found in concentrations ranging between 7.19 and 43.59 mg kg À1 fresh weight, while naringenin levels were lower than 12.55 mg kg À1 . The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32 mg kg À1 fresh weight, followed by caffeic acid, while p-coumaric and ferulic acids showed similar concentrations lower than 5 mg kg À1 . The highest content of lycopene was found in Ramillete, Pera and Durina (>50 mg kg À1 fresh weight), while the concentration in the other varieties was between 50 and 30 mg kg À1 , with the exception of Liso (less than 20 mg kg À1 ). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be signi®cantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid.

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Hydroxycinnamic acids are consumed as water-soluble conjugates and in larger amounts bound to plant cell walls. Bound acids are primarily released by microbial action in the modiüed forestomach of ruminants and the hindgut of non-ruminant species, including humans. In the rumen, rapid hydrogenation of p-coumaric, ferulic and caþ eic acids, followed by dehydroxylation at C4 and more slowly at C3 yields 3-phenylpropionic acid. Phenylpropionate is absorbed and undergoes boxidation in the liver to benzoic acid which is then excreted predominately (75-95% ) as its glycine conjugate (hippuric acid), but also as the free acid or glucuronide. In non-ruminants, hydroxycinnamates may be absorbed unchanged in the upper digestive tract via a Na'-dependent saturable transport system or escape to the hindgut where they are subject to microbial transformations with further absorption of metabolites. Metabolites of p-coumaric acid found in rat urine are the unchanged compound and its glycine conjugate, the reduced derivative and the b-oxidation product, 4-hydroxybenzoic acid. Caþ eic acid and its methyl ethers (ferulic and iso-ferulic acids) are interconvertable and share metabolites. As in the rumen, reduction of the side-chain, demethylation of C 3 ferulate and dehydroxylation at C4 are products of microbial action. Dehydroxylation at C3 is more rarely encountered. The resulting 3-hydroxyphenylpropionic acid is commonly found in the urine of all species and is the major metabolite in rats where relatively little chain-shortening occurs. A larger range of metabolites including compounds have been detected in human urine. Metabolism of C 6 -C 1 hydroxycinnamate dimers found as cross-links between polysaccharide chains has been little studied although evident diþ erences in the ability to metabolise such compounds exist between the human and rumen microýora.

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Abstract:The upper five internodes were collected from maize (Zea mays L) inbred cell lines Co125 and W401 harvested at the same developmental stage, 5 days after silking. Each internode was dissected into ten equal lengths labelled A (top) to J (base). The youngest cells were found in section J, which contained the intercalary meristem, and the oldest in section A. Internodes 1, 3 and 5 provided material for chemical analysis and internodes 2 and 4 for degradability measurements. Cell wall material accounted for one-third of dry matter in section J, doubling to two-thirds in the upper half of each internode. Only section J exhibited a polysaccharide profile typical of primary cell walls. In all other sections, 1,Clinked glucose (-46 % of cell wall) and xylan largely free from side chains (-25% of cell wall) predominated. Net accretion of cell wall polysaccharide reached a maximum by segment G and thereafter little additional carbohydrate was deposited. Lignification appeared to be separated from the biogenesis of structural carbohydrate and continued over much of each internode reaching a maximum in section C. Degradability measurements, made using a modified neutral-detergent cellulase digestibility method, showed substantial differences between sections. In line Co125, cell wall degradability fell from over 95 % in the youngest section (J) to approximately 24 % in section B. Internode 4 of line W401 failed to show the same pattern of degradabilities, probably because of a sequential rather than simultaneous pattern of internode elongation. Saponifiable p-coumaric acid appeared to provide a more sensitive marker than lignin of the extent of secondary wall development. The inverse relationship between extent of lignification in each section and its degradability confirmed the value of the internode model for the study of secondary wall formation and its biological consequences.