STUDIES ON FRUIT JUICES. 11 



Sterilization and keeping after sterilization. — The characteristic 

 color and flavor were well retained in juices sterilized and kept after 

 sterilization at ordinary temperatures, even for periods as long as 

 several years. 



Application of special methods. — Keeping the juice after steriliza- 

 tion at low temperatures or in carbon dioxid did not result in a product 

 perceptibly better in quality than did keeping it under usual condi- 

 tions where, as stated before, the distinctive qualities were excel- 

 lently well retained. Upon concentration by freezing, a very viscid 

 highly acid concentrate was obtained. 



Jelly making from sterilized juice. — Excellent jellies were easily 

 prepared from sterilized black currant juice by adding an equal 

 weight of sugar and cooking. 



Discussion. — Juice of black currants may be prepared readily by 

 cooking, pressing, and sterilizing in sealed containers. It is practi- 

 cally unaffected in color and flavor by sterilization, and the color and 

 flavor are well retained. Application of special methods to secure 

 the retention of color and flavor is therefore unnecessary. 



BLACKBERRY JUICE. 



The data are based on results obtained with wild blackberries and 

 with the following cultivated varieties: Eldorado, Early Harvest, and 

 Erie. 



Pressing. — Cooking before pressing increased the yield and gave 

 juices possessing the desirable aroma and flavor of cooked blackber- 

 ries. It was necessary to apply the pressure very gradually to avoid 

 pressing the pulp through the press cloths. Yields when cold pressed 

 ranged from 66.9 to 69.6 percent; hot pressed, from 74.4 to 80. 9 per 

 cent. 



Sterilization. — The juices lost but little in flavor and color on being 

 sterilized. 



Keeping after sterilization.— Upon being kept at ordinary tempera- 

 tures after sterilization the distinctive blackberry color and flavor 

 were well retained for a period of at least 6 months. On keeping 

 for longer periods the flavor gradually lost its blackberry character, 

 and the color slowly faded. Juice kept at from 32° to 35° F. and in 

 carbon dioxid after sterilization was not perceptibly superior in 

 distinctive flavor and color to that kept at ordinary temperatures in 

 air. 



Concentration by freezing. — The juice was easily concentrated by 

 freezing. 



Discussion. — A satisfactory method of preparing the juice of wild 

 or cultivated blackberries based on the foregoing results consists in 

 cooking the berries, pressing them, freeing the juice from sediment and 

 sterilizing it in bottles. Though quite acid, juices of both wild and 

 cultivated varieties are attractive when so prepared. 



