Value added fish by-products - Nordic Innovation

Ash content was estimated by charring in a crucible at 550 o C until the ash had a white
appearance (Aoac 1990)
2.3.1.2 Degree of hydrolysis
The degree of hydrolysis was evaluated as the proportion (%) of α-amino nitrogen with
respect to the total N in the sample (Taylor 1957). Analyses were performed in duplicate.
2.3.1.3 Molecular weight distribution
Dry powder was dissolved in doubly distilled water (10 mg/ml) and centrifuged at 7840*g for
10 minutes and separated on a FPLC column (®Superdex 75 HR 10/30), the flow rate was 0.5
ml/min and the standards used were Bovine serum albumin (Mw 67000), Myoglobin (Mw
17600), Cytochrome c (MW 12270) and Vitamin B12 (Mw 1355).
2.3.1.4 Colour measurements
Colour measurements were performed using a Minolta Chroma Meter CR-200/CR231. L*
(lightness), a* (redness) and b* (yellowness) of the dry powders were recorded.
Measurements were performed in quadruplicate.
2.3.1.5 Emulsifying properties
Emulsification capacity was measured by mixing 5 ml of rapeseed oil with 5 ml of a 1% FPH
solution in water and homogenising (Ultra – Turrax TP 18/10) in 15 ml graded Nunc
centrifuge tubes at 20 000 rpm for 90 s. The emulsion was centrifuged at 2400*g for 3
minutes Slizyte et al. 2005b. The volume of each fraction (oil, emulsion and water) was
determined and emulsification capacity was expressed as millilitres of emulsified oil per 1 g
of FPH (Kinsella 1976). Emulsion stability was expressed as percentage of initial emulsion
remaining after a certain time (1 day at room temperature) and centrifugation at 2400*g for 3
minutes (Mcclements 1999). Tests were performed in duplicate.
2.3.1.6 Water Holding Capacity (WHC)
FPH powder was added to fish mince for evaluation of the ability to influence water holding
capacity of fish mince. FPH powder (2% of minced muscle mass) was added to fish mince
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