I.水果中各部位之果膠含量

Part I. Pectin content in the component part of fruits

就臺灣產之各種水果採用操作簡單而迅速準確之配位滴定法測其各部位之果膠含量。因本法所求出者為calcium polygalacturonate之純量，如與以往慣用之Carre & Haynes法所求出之 calcium pectate尚含有其他附隨物者相比較時，本法所得之數字略低。果膠含量最高者為柑橘類之瓢囊膜，在柚類之瓢囊膜高達6%以上。所有柑橘類之皮部果膠含量均達2%以上。其他水果之果皮中含果膠較豐富者為檬果、柿、百香果，約在1.5%以上，而木瓜、番石榴、香蕉等之皮含果膠約為0.5-1.0%。果肉中含固形物較多之材料如香蕉、番石榴、木瓜等約含果膠0.5-1.0%，反之果肉中屬於多汁者如鳳梨、西瓜、甜瓜、龍眼、荔枝等果膠含量均甚低僅在0.2%以下。不同收穫季之鳳梨，各部位之含果膠量均甚少，尤以冬果之含量為最低。香蕉隨追熟之進行，果皮中之果膠含量漸見減少，而果肉中果膠之含量似無增減。柑橘類以初生柑橘亞屬如甜橙、柚類等之果膠含量最豐富，後生柑橘亞屬如椪柑、溫州蜜柑及金柑等果膠含量則較低。以本省桶柑果肉罐頭製造之廢皮推算，其中約有100噸之果膠如能將其提十分之一，亦將有10噸果膠可能足供本省之利用。

Chelatometric titration has been used for the determination of pectin content in the component part of various fruit produced here in Taiwan. Total pectin content in each part of the fruits is expressed as calcium polygalacturonate in fresh material. This expressed value will°be more accurate but still smaller than the calcium pectate determined by the well-known Carre & Haynes gravimetric method. The highest content of pectin is found in the segment membrane of citrus fruits; those as pomeloes contains more than 6% Citrus peels, with pectin content more than 2% are rich resources of pectin. The peels. of mango, persimmon or passion fruit have pectin content more than l.596, while those in the peels of papaya guava or banana etc. are 0.5 to 1.0% There is also 0.5 to 1.0% of pectin contained in the fibrous flesh of banana, guava or papaya, however, very poor contents of less 0.2% are indicated in the juicy pulp of pineapple, water melon, melon, longan or lichi, etc. Pineapple contains very poor amount of pectin throughout every harvest­ing season, epecially in its winter harvested fruit. During the ripening of banana, the pectin content of its peel is gradually decreased, but no evident change was found in the flesh portion. The fruits of archicitrus, such as sweet orange and pomelo, etc., seem to be richer in their pectin content than those of metacitrus, such as ponkan, Satsuma orange and kumquat etc. About 100 tons of pectin may be contained in the waste peels of mandarin orange from canneries here in Taiwan. lf its one tenth can be recovered, it will sufficiently cover the demand of pectin for the utilization in this island.