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Titolo:
Inhibition by alpha-tocopherol and L-ascorbate of linoleate hydroperoxidation and beta-carotene bleaching activities in durum wheat semolina
Autore:
Pastore, D; Trono, D; Padalino, L; Simone, S; Valenti, D; Di Fonzo, N; Passarella, S;
Indirizzi:
Univ Molise, Fac Agraria, Dipartimento Sci Animali Vegetali & Ambiente, I-86100 Campobasso, Italy Univ Molise Campobasso Italy I-86100 Ambiente, I-86100 Campobasso, Italy Ist Sperimentale Cerealicoltura, Sez Operat Foggia SS, I-71100 Foggia, Italy Ist Sperimentale Cerealicoltura Foggia Italy I-71100 71100 Foggia, Italy Univ Bari, Dipartimento Biochim & Biol Mol, I-70126 Bari, Italy Univ BariBari Italy I-70126 nto Biochim & Biol Mol, I-70126 Bari, Italy
Titolo Testata:
JOURNAL OF CEREAL SCIENCE
fascicolo: 1, volume: 31, anno: 2000,
pagine: 41 - 54
SICI:
0733-5210(200001)31:1<41:IBAALO>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
SOYBEAN LIPOXYGENASE-1; PLANT; ACID; QUALITY;
Keywords:
lipoxygenase; durum wheat; semolina bleaching; alpha-tocopherol; L-ascorbate; enzyme inhibition;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Passarella, S Univ Molise, Fac Agraria, Dipartimento Sci Animali Vegetali & Ambiente, Via Sanctis, I-86100 Campobasso, Italy Univ Molise Via Sanctis Campobasso Italy I-86100 sso, Italy
Citazione:
D. Pastore et al., "Inhibition by alpha-tocopherol and L-ascorbate of linoleate hydroperoxidation and beta-carotene bleaching activities in durum wheat semolina", J CEREAL SC, 31(1), 2000, pp. 41-54

Abstract

In order to gain some insights into durum wheat lipoxygenase (LOX) biochemistry and in particular in order to find out whether the antioxidants alpha-tocopherol and L-ascorbate can prevent the LOX-dependent semolina bleaching, which leads to a low quality of pasta product, a study of LOX activity in a crude protein extract from semolina was performed by means of spectrophotometric techniques. Measurements made of linoleate hydroperoxidation reaction (lambda = 234 nm) and of the coupled beta-carotene bleaching reaction (lambda = 460 nm), demonstrated the existence of more than one enzyme exhibiting LOX activity as revealed by the different pH profiles. The linoleate hydroperoxidation reaction exhibited a sigmoidal dependence on the substrate concentration (K-0.5 = 60 +/- 0.67 mu M, V-max = 1.12 +/- 0.055 units/g of semolina), while beta-carotene bleaching showed a hyperbolic relationship and followed the Michaelis-Menten equation (K-m = 3.3 +/- 0.53 mu M V-max = 0.030 +/- 0.0062 units/g). Both linoleate hydroperoxidation and beta-carotene bleaching were stronglyinhibited by added alpha-tocopherol. In both cases, the enzyme affinity for the substrate was reduced, while the V-max was not affected. In particular, beta-carotene bleaching was inhibited in a competitive manner (K-i = 7.7+/- 0.21 mu M) L-ascorbate also inhibited both reactions: the V-max, of linoleate hydroperoxidation was lowered, while the K-0.5 remained unchanged; in the case of beta-carotene bleaching the inhibition was uncompetitive (k(i) = 445 +/- 71.5 mu M). Therefore, the use of both alpha-tocopherol and L-ascorbate to reduce semolina bleaching during pasta making is suggested. A purification procedure of semolina LOX is also reported, showing the existence of two isoforms. (C) 2000 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/11/20 alle ore 21:52:12