COMMERCIAL CANNING OF FOODS. 



23 



Tlie cut-out weight of fruit will not be the same as the weight of fruit introduced, 

 but will vary according to the structure and state of maturity of the fruit and the 

 method of handling. A fruit which is very succulent and h2,s little supporting tissue, 

 such as strawberries or raspberries, undergoes heavy shrinkage, depending upon the 

 strength of the sirup used, while a pear, with its stronger supporting tissue, will suffer 

 little change. The sugar of the sirup unites with the plant juice, and abstracts a 

 part of the water. The fruit loses in weight, the sirup gaining a proportionate amount. 

 The changes in weight, however, are not as great as those, in volume. The most 

 marked decrease in the weight of fruit is apparent shortly after processing, after which 

 a gradual increase takes place until the sugar in the fruit and that in the sirup become 

 equalized. Just how much time is required for this process has not been determined. 



As an illustration of the changes going on within the can, the analysis of two lots of 

 blackberries and the weights of apricots, chen'ies, peaches, and pears are given. The 

 first analysis of the blackbeiTies was made the day after canning, the second 70 days 

 later. The weights on the other fruits were taken for the first reading within 30 days 

 after packing and for the second from 120 to 180 days later. The cans were not selected 

 to have a definite and uniform weight, so that the gross weight varies somewhat, but 

 the change in each case goes on in one direction, as is shown in the table. The average 

 given is for seven samples in each set. 



The effect of standing on changes in composition of blackberries and on the weight of solids 

 and sirup of apricots, cherries, peaches, and pears. 



Kind of fruit and 

 time of standing. 



Gross 

 weight. 



Weight 



of 

 contents. 



"Weight 



of 

 fruit. 



"Weight 



of 

 sirup. 



BrLx 

 reading. 



Reduc- 

 ing sugar. 



Sucrose. 



Acidity 



(as citric 



acid). 



Blackberries, 50° 

 sirup: 



1 dav 



Grams. 

 1,050 

 1,049 



992 

 1,010 



1,023 

 1,013 



1,018 

 1,013 



1,030 

 1,027 



977 

 979 



1,010 

 l,02.j 



982 

 988 



Grams. 

 910 

 909 



852 

 870 



883 

 873 



875 

 873 



890 



887 



837 

 839 



870 



885 



842 

 848 



Grams. 



384 

 428 



465 

 553 



465 

 563 



545 

 570 



507 

 542 



500 

 569 



503 

 605 



532 

 565 



Grams. 

 526 



481 



387 

 307 



418 

 337 



333 

 303 



383 

 345 



331 



277 



367 

 280 



310 

 283 



Degrees. 

 31.6 

 29.1 



15.6 



17.7 



20.7 

 20.0 



18.1 

 17.5 



21.5 

 21.0 



10.1 

 16.5 



22.2 

 22.3 



16. 6 

 17.8 



Grams per 

 100 cc. 

 9.93 

 12.35 



Grams per 

 100 cc. 

 18.27 

 13.71 



Grams per 

 100 cc. 

 0.42 



70 days 



.56 



Apricots, standard: 

 First reading 





Second reading... 

 Apricots, e.xtra stand- 

 ard: 



First reading 



Second reading 





















Cherries, standard: 



First reading 



Second reading... 

 Cherries, extra stand- 

 ard: 



First reading 



Second reading... 

 Peaches, standard: 



First rea'Jing 

































8<*ond rcafiing. .. 

 Peaches, e.xtra stand- 

 ard: 

 First reading 















Second reading... 

 Pears, extra stand- 

 ard: 



First reafllng 



Second rea^Jing... 



























Unfortunately, syHtematic data art; not available concerning the rate or extent of 

 the changes. Some of the bott<!r ]jacker.4 recogiiiz(! tlicse changcH in a practical way 

 by rofuHing to Hond out HamjjleH of fruitH mxjner tliaii .'50 or 40 dayn after packing, stating 

 that at firHt neither the ap]>(!arance nor tlie flavor in what it will be after Htan<ling. 

 While a heavy ninij) iini<\» to Hoft<;n and Hhrink ri])*; fruit, it Ikih less effect on tliat wliich 

 in Hlightly und(;rrii>e or green. Tlie underripe; fruit giv<!M Hhar])er, cleaner-cut edges, 

 CHpecially with ftcachcH, jifiarw, and a]>ricolH, and Ichh color and fewer ))articleH of fruit 

 ia the Hinip. The U-ndency to exaggerat*; thesf! pointn of ajijiearance ac(;ouiitH for tho 

 uijc of Homo mutfjrial which would be imjirovi;*! in flavor if it were allowed to mature 



