Pro‐ und Antioxydantien auf dem Fettgebiet XXV: Über ihre Lokalisierung in Samen und Früchten sowie in Kartoffeln

Abstract

f i t 1 u 11 t i , D r . A. W . E 1 B (I y n iiml Lrdwtr ~t t i i~t d -C l i v t t z .U. M (7 i ti ren Arts r l c v B i i n r l~~s r~t i s f r i l~ lrir Frlfjorsrlritrrg. M t i i z s t f r (Wrsfj.)Dic antioxydative Wirkung verschiedener Pflanzenextrakte wurde an hochgcreinigtem I.addeinij1 sowie Linolsiiurc-methylester bestimmt. Extrakte aus den periphcren Zonen versrfiic-dener Fruchtc bcsitzen die maxirnalc oxydationshemmende Wirkung, und zwnr in Abhangigkeit von Sorte und Lagerungsdauer. Das Flavonol Quercetin kommt irn Kiihenzwiebel-Fleisch als Glykosid und nicht in freier Form vor. Im Zusarnmenhang mit der Haltbarkeit von Kartoffelprodukten wahrend der Lagerung wurden der Lipoid-Gehalt und die Verteilung der 1,ipoide zwisrfien Starke und EiweiD in der Kartoffel ermittelt. Die Mijglichkcit einer eventuellen Verwertung der in Kartoffelsrfialen befindlihen Antioxydantien wird diskutiert. Antioxidative action of various plant extracts on highly purified linseed oil and methyl linoleate w a s determined. Extracts from the peripheral zones of different fruits possess the maximum oxidation inhibiting action, which depends on the variety and the period of storage. 'The flavonol quercetin occurs in the flesh of onions as glycoside and not in free state. In connection with the stability of potato products during storage, thc lipid content and the distribution of lipids between star& and protein of the potatoes are determined. The scope of a possible utilization of the antioxidants present in the potato skins is discussed.

Flavonols and flavones in food plants: a review†

“…Outer dry skins contain 2.5 to 6.5% quercetin as reported in the literature (Herrmann, 1958;Varshney & Ali, 1971 ;Kaufmann, el Baya & Meinsen, 1969). Quercetin appears mainly in the free form, i.e.…”

“…It has been shown also that quercetin in concentrations of 15 mg/100 g is a very active antioxidant for butter fat and lard (Richardson, El-Rafey & Long, 1947;Morris & Riemenschneider, 1949). Other flavonols show similar effects although less actively than quercetin (Kaufmann & el Wahab el Baya, 1967). The position and the number of free hydroxyl groups in flavonols are responsible for their antioxidative activity.…”

“…It is believed that the 3-hydroxyl group in conjunction with the 2,3-double bond are of decisive significance. If the 3-OH group is bound glycosidically or if it is absent, as in the case of flavones, the antioxidative activity is weakened (Kaufmann & el Wahab el Baya, 1967).…”

“…Extracts of the skins of yellow onions which are rich in quercetin inhibit, in a concentration of 0.01 %, the auto-oxidation of methyl linoleate which is used frequently as a test substance for the investigation of the oxidation of unsaturated fats (Kaufmann, el Baya & Meinsen, 1969).…”