Effect of Different Drying Techniques on the Nutrients Content of Fish Feedstuffs

The study investigated the effect of different drying techniques (air dying, oven drying and sun drying) on the proximate composition of three fish feedstuffs; Horse radish (Moringa oleifera) leaves, water lily (Pistia stratiotes) leaves and soy bean (Glysine max) seed. The soy bean was boiled for 30 minutes at 100C in water bath to reduce the effect of anti-nutritional factor (trypsin). Samples of each feedstuff were prepared and subjected to the three dying methods in triplicate treatments. Determination of proximate composition was carried out on the dried and fresh samples of each feedstuff. The results showed that moisture content of fresh M. oleiferaleaves (65%) and P. stratiotes leaves (85.67%) were significantly higher (P< 0.05) than fresh G. max(2.67%). Higher crude protein content of 23.97% and 22.50% were recorded for oven-driedM. oleifera and P. stratiotesleaves and 39.21% for freshG. maxwith no significant difference (P> 0.05) between the treatments. Crude lipid was significantly higher for sun dried samples of all the feedstuffs. Oven-dried samples of the three feedstuffs had the least ash, crude fiber and nitrogen free extract. The study concluded that oven drying at moderate temperatureof 700C proved to be more effective in moisture removal and retention of crude protein. Furthermore, the study recommends a feeding trial to assess the potential of these feedstuffs subjected to various drying methods on growth and nutrients utilization of cultivable fish species.

Abordagem sobre os diferentes processos de secagem empregados na obtenção de extratos secos de plantas medicinais / Approach on different drying processes employed for obtaining dry extracts from medicinal plants

Na indústria farmacêutica de fitoterápicos, o extrato seco é considerado tecnologicamente viável para fins de produção em larga escala, devido à estabilidade física, química e microbiológica, além da facilidade de padronização dos princípios ativos. Entre as técnicas de secagem empregadas na preparação de extratos secos, encontra-se a nebulização ou spray-dryer, o leito de jorro, a liofilização e a evaporação rotativa. A escolha do processo de secagem é motivada pela potencialidade dos diferentes equipamentos secadores, na secagem de materiais presentes na forma líquida, no caso, soluções extrativas de plantas medicinais, fornecendo um produto de alta qualidade e com investimento relativamente baixo.

In the pharmaceutical industry of herbal medicines, the dried extract is considered technologically feasible for large-scale production, due to its physical stability, possibility of chemical and microbiological analyses and the ease of standardization of the active ingredients. Among the drying techniques used in the preparation of dry extracts are a mist or spray-dryer, the spouted bed, freeze-drying and rotary evaporation. The choice of the drying process is motivated by the potential of different drying equipments and materials present in liquid form, in this case, solutions of herbal extracts provide a high quality product and a relatively modest investment.