Value added fish by-products - Nordic Innovation

3.1.7 Water activity (aw)
The water activity of the gelatin powders were determined using an aw measuring apparatus
(Novasina aw CENTER, Novasina, Pfåffikon, Switzerland). Samples were analysed in
triplicate.
3.1.8 Colour
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. Whiteness was
calculated according to the methods of Park (1994):
Whiteness = L * -3b *
The instrument was calibrated against a white standard at the same light conditions and
temperature (20°C). The analysis was performed five times on each sample. Gelatin
solutions (3% w/v) were measured.
3.1.9 FT-NIR
FT-NIR spectra of the dried gelatins were recorded on MPA - Multipurpose analyser
(Bruker Optics, Germany). The spectra´s were collected in reflectance mode in the 12500-
4000 cm -1 region using fiber optic module. The fiber optic probe measures over an area of
0.50 cm 2 . The scanners speed was 40 kHz and each spectra was average spectrum of 16
scans. Each sample was collected four times and the mean of four spectra of the samples was
used to analyse.
3.1.10 Dry addition of the gelatins to fish mince
Samples with mince from saithe (Pollachius virens) were prepared (Table 3.1). The mince
samples were prepared with gelatin concentration of 0, 0.5, 1.5 and 3% (w/w). The samples
were then frozen at -24 °C for approx. 7 days. Samples were thawed at +2 °C for 48 h prior
analysing. During thawing, additional water in the mince samples were allowed to leak out
and the yield after freezing/thawing determined. Thaw drip (%) was determined as the loss in
weight during thawing.
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