A Study on the Contents of Pectic Substances in Fruits, Vegetable fruits and Nuts

Abstract

Since it has been found that pectin has lowering action of the plasma cholesterol, the physiological role of this substance has been noticed from the view point of the prevention of atheriosclerosis.In the present paper, the contents of pectic substances in fifty kinds of fruits, vegetable fruits and nuts were examined.At first the citrus were separated into peel, pulp, juice and seeds.Non-eatable parts in other fruits, vegetable fruits and nuts were removed. Each sample was treated with boiled 70% ethyl alcohol to remove sugars, and fat-rich nuts were fattened out by ether, and dried.The dried alcohol-insoluble solids (AIS) were successively divided by fractional extraction into three fractions which were soluble in water at 30°C, 0.4% sodium hexametaphosphate at 30°C, and 0.05N hydrochloric acid at 85°C. The pectin contents as Ca-pectate of in each pectin-soluble fraction were quantitatively determined by a method of Carré and Hayness.The total content of pectic substances in the fresh material was as follows:1) Citrus4% or higher: Mandarine, peel3.00-3.99%: Kumquat pulp, Shaddock pulp, Shaddock peel, Uzu pulp2.00-2.99%: Fingered citron, Uzu peel1.00-1.99%: Kumquat peel, Mandarine pulp0.99% or less: Kumquat juice, Mandarine juice, Shaddock juice, Uzu juice2) Other fruits2.00-2.99%: Pawpaw, Avocado1.00-1.99%: Chinese quince, Fig, Red currant0.50-0.99%: Apple (Kogyoku), Apple (Starking), Gooseberry, Banana (Ecuador), Apple (Delicious), Apple (Fuji), Apple (Indo), Banana (Philippine), Banana (Taiwan), Japanese persimmon, Apple (Kokuko), Strawberry, Kiwi, Mango, Papaya Quince0.49% or less: Japanese pear (Nijusseiki), Pear, Cherry, Plum, Apricot, Peach, Ume apricot, Banana (Cooking-banana), Apple (Mutsu), Wax jambu, Japanese pear (Chojuro), Loquat, Grape (Chambell), Grape (Dalaware), Grape (Neo-muscat), Grape (Kyoho), Pinneapple, Japanese pear (Kosui)3) Vegetable fruits0.50-0.99%: Balsam pear0.49% or less: Tomato, Water melon4) Nuts5% or more: Walnut, Peanuts shelled1.00-1.99%: Chestnut