Test of Sweet Sorghum as a Raw Material for Production of Sweet Substances

Abstract

The sweet sorghum (Sorghum bicolor var. Saccharatum H.), has been well known for more than a century in Bulgaria, used for extraction of sweet syrups. The modern varieties of sweet sorghum, except the old forms of local populations and standard varieties, include various hybrids with Sudangrass, Sorghum bicolor var. technicum and var. eusorghum. The results of productivity tests of standard varieties, populations and hybrids of the breeding program of Agricultural Institute – Shumen are reported. The tested sweet forms of sorghum and their hybrids form a mean yield of 52.3 – 73.5 t/ha biomass with 53.7 – 63.4% dry matter content and 63% of stems. There have been selected populations and hybrid forms sweet sorghum with high productivity and with higher percentage in stems of keeping succulence even in the late stages of development. The rates of yield of the pressed juice from the stems as a ratio between the mass of the juice and the biomass weight varies from 17.3% to 35.6% depending on the genotype and correlates with the higher part of the stems and the succulence at the end of vegetation. The average values of 16.7% dry matter, 12.6% total sugars and 9.0% sucrose of the pressed juice make it effective the receipt of concentrated sweet syrups with 60 – 70% dry matter content and 14 – 18% rates of yield, or 8 – 10 t/ha of syrup, depending on the genotype and the cultivation conditions.