Value added processing of dehydrated and suncured alfalfa
A pilot scale pellet mill was used to produce pellets using ground alfalfa leaf and stem fractions. Both suncured and dehydrated alfalfa chops were used in the experiments. The moisture content of the suncured and dehydrated chops was 8.4 and 9.6% (wb), respectively. A stack of two square sieves with different opening sizes and a pan were used to separate leaf and stem fractions. The leaf and stem fractions were further segregated into two sample lots and ground in a hammer mill using two screen sizes of 3.20 mm (1/8 in.) and 1.98 mm (5/64 in.). The leaf and stem fractions from each sample lot of same grind sizes were combined to get five different samples with leaf content ranging from 0% to 100% in 25% increments. The moisture content and temperature of the samples were raised to 10-11% (wb) and 76oC, respectively, in a double chamber steam conditioner prior to the pelleting operation. The temperature of material was further raised to 95oC in the pellet mill due to the friction between its roller-die assembly. Average particle sizes of sample lots were determined. Temperature and moisture content of samples after various pelleting stages were recorded. High durability pellets were produced using fractionated suncured alfalfa irrespective of grind size (except for 100% stems, which was low). Durability fluctuated between high and medium range for dehydrated alfalfa (except for 100% stems, which was low). Dehydrated alfalfa produced pellets with greener color, while suncured alfalfa produced harder pellets.
Soils and Crops Workshop