Refractance window drying of fish silage – An initial investigation into the effects of physicochemical properties on drying efficiency and nutritional quality

Publication date: March 2019Source: LWT, Volume 102Author(s): M. van ‘t Land, K. RaesAbstractThe goal of this study was to investigate changes in nutritional quality of fish silage during refractance window (RW) drying. Furthermore, the effect of protein hydrolysis-degree of fish silage on production efficiency (%-moisture evaporated and production rate) was determined. To acquire a dried product, fish silage was conveyed (30 cm/min) on a polyester film over a water bath of 55 °C. Moisture content decreased from 747 ± 24 g/kg to 101 ± 33 g/kg, with only a slight increase in TBARS, from 3.7 ± 1.0 mg/kg to 6.3 ± 0.8 mg/kg. End-product consistency seemed to be affected by application thickness, ambient conditions and protein hydrolysis-degree. Additionally, a higher protein hydrolysis-degree increased evaporation efficiency, resulting in moisture contents of 135 ± 10 g/kg, 101 ± 12 g/kg, and 67 ± 24 g/kg, for low-DH, medium-DH, and high-DH, respectively; though production rate decreased, producing dry matter outputs of 1.60 ± 0.06 kg/h, 1.21 ± 0.03 kg/h, and 1.05 ± 0.06 kg/h, respectively, possibly caused by an increased availability of free water and a reduced application thickness. RW-drying seems to be an effective way of rapidly drying fish silage under gentle conditions.
Source: LWT Food Science and Technology - Category: Food Science Source Type: research