Abstract
The contents and composition of sugars, acids and pectic substances were compared between 5 varieties of european pear. Total sugar contents at harvest time are 9 to 11% in “Bartlett”, “La France” and “Passe Crassan”, and those in “Winter Nelis” after 40 days cold storage and in “Doyenne du Cornice” after 60 days cold storage are 12% and 11% respectively. Main sugar components are sucrose, glucose, fructose and sorbitol in all varieties investigated here. Fructose is most dominant sugar, this ratio to total sugar content occupied 60-70% in “Bartlett”, “La France” and 81-85% in other three varieties. Free acid content at harvest time are 0. 3-0. 4% in “Bartlett” and about 0.2-0.3% in other varieties. The dominant acid is citric acid in “Bartlett” alone, and malic acid in other varieties. Total pectic substances content at harvest time were about 400mg per 100 g of fresh fruit in “Bartlett”, 500-600mg in “Passe Crassan” and 470-690mg in “La France” respectively. Water-soluble ratio to total pectin content was about 20%, sodium hexameta-phosphate-soluble ratio about 10%, and NaOH-soluble ratio about 70%. Water soluble ratio increased to more than 60% with after-ripening, NaOH-soluble ratio decreased to 20-30% in the stage of ripeness suitable for eating.
