230 



TECHNICAL BULLETIN 15 



Chart 3. Influence of Ratio of Apple to Water on Recovery (Yield) of Soluble Solids 

 and Pectin in Sliced and Chopped Baldwin Apples. Temperature of Extrac- 

 tion 100° C. 



90 



EZ2 TmsT EXraACTloK 

 CZl .SECOttD EXTRACTION 



Sliced Chopped 



SOLUBLE SOLIDS 



* Ratio of apple to water by weight. 



Sliced Chopped 



PECTIN 



to as much as 10 per cent of the total and averaged about 5 per cent. It 

 was greatest where the extraction temperature was low, i.e., 88° C. (190° F.) ; 

 it was negligible at the boiling temperature and finally became negative at 

 109°C. (228° F.). The probable cause of the decreased recovery of sugar, 

 acid and pectin at 109 °C. was the poor heat conductivity of the chopped 

 apple mass. This resulted in lower temperatures in the mass itself t!ian was 

 indicated by the retort thermometer. This was experimentally proved. It 

 took more than 30 minutes for a retort temperature of 109°C. to bring the 

 whole of the apple pulp to that temperature. For this reason, in all pressure 

 cooker extractions under 30 minutes, the temperature of the chopped pulp 

 mass was below 109°C. This readily explains the poor recoveries obtained 

 at this seemingly high extraction temperature. On the other hand in the 

 pressure cooker, sliced apples allowed ready penetration of heat, largely 

 due to unimpeded convection currents and increased conductivity in the 

 ai)ple — water medium. Where the amount of water used for extraction 

 was large, as in the 3:4 ratio, there was an increase in the time necessary 

 to bring the mass to the desired temperature. After reaching this point, 

 however, the temperature of the mass was relatively constant, due. to the 

 large volume of liquid present. 



Where the ratio of fruit to water was 3:2 the chopping of the fruit had 

 a slight inimical effect upon yield of soluble solids, acid, and pectin. Where 

 the ratio was 3:3 or 3:4 the chopped fruit usually yielded considerably more 

 of these substances than the sliced. Thus it appeared that where the apples 

 were ground up or chopped, tlie ratio of fruit to extraction water siiould be 

 widened over that necessary where the fruit was sliced. For sliced fruit, a 



