Value added fish by-products - Nordic Innovation

AOAC 937.18 (2000). Crude protein content was estimated with the Kjeldahl method (ISO,
1979) and by multiplying the nitrogen content by 6.25.
TVB-N content of samples was measured using direct distillation into boric acid (based on
AOAC 1990). The acid was then titrated with a diluted sodium hydroxide solution. The
unbound ammonia was calculated as g/16g N.
1.3.1.2 Texture and colour
Prior measurements of textural properties, samples were steam cooked at 98°C for 15 min.
The samples were then cooled down at room temperature and refrigerated prior analysis.
Textural properties of the samples (3x3 cm and 3x5.5 cm in size) were measured by using
TA-XT2 (TA-XT2 Texture Analyser, Stable Microsystems, Surrey, UK). The samples were
pressed downwards twice at constant speed of 1 mm s -1 into the samples until it had reached
55% of the samples height. The data processing was done in a program called Texture Expert
Exceed, version 2.64.
Colour was measured with Minolta CR-400 Chroma meter (Minolta Camera Co., Ltd., Osaka,
Japan) using the CIE Lab scale, with L * (black 0 to light 100), a * (red 60 to green -60) and b *
(yellow 60 to blue -60) to measure lightness, redness and yellowness.
1.3.2 Fish balls
Fish protein isolate (FPI) made from haddock (Melanogrammus aeglafinus) cut-offs by the
pH-shift process was added to haddock mince in two different proportions (Table 1.2) to
manufacture two types of fried fish balls. The products were assessed for physical properties
and sensory changes within the period of 8 weeks of freezer storage at -18°C.
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