Sap extraction on sorghum and the localization of juice and sugars in internodes of the plant

1. The percentage juice and the total sugars of juice extracted from sorghum plants in the process of crushing for syrup manufacture were determined on plants given the following treatments: (a) Cut without stripping leaves at time of crushing; (b) cut with stripping leaves at time of crushing; (c) stripped, cut, and left to lie in a pile for various intervals before crushing; and (d) unstripped and left lie in piles before crushing. 2. It is clearly shown that there is a proper time for harvesting sorghum in order to obtain high percentage of juice and of total sugar (Fig. 5). The highest total sugar was obtained from October 1 and October 4 cuttings; less from the September 25 cutting and later dates in October. 3. There is some difference in the value of internodes from different parts of the sorghum stalks, the central having the highest, the lower ones an intermediate, and the uppermost the least value (Fig. 2 and Table 1). 4. Heavy pressure during the processes of crushing the sorghum stalks usually gave the higher amounts of sugar and juice (Table 3). 5. By repeating the crushings three times and by increasing the pressure of the rollers in each case, the respective crushings yielded total sugars in ratio of 2.71:2.4:1.26, or in percentage, approximately 43:40:17. 6. Stripping of leaves from the plant three to four days previous to cutting and crushing caused a slight depression in amounts of total sugars obtained on various dates (Table 2). 7. Allowing the stalks to remain in piles several days after cutting increased the sugar content of the juice probably due to two reasons, namely, evaporation, thereby making the sap more concentrated; and hydrolyses of starch and dextrins to sugars. 8. Allowing leaves to remain on stalks in each instance reduced the percentage of juice and the total amount of sugars (Table 2).