Preparation and characterization of protein isolate from Yellowfin tuna Thunnus albacares roe by isoelectric solubilization/precipitation process

Table 1 Proximate composition of FDC, roe alkaline insolubles (RAIs) as 2’nd byproducts and roe protein isolates (RPIs) by isoelectric solubilization and precipitation (ISP) process

Sample	Yield^a (g)	Protein yield^b (g)	Moisture (%)	Protein (%)	Lipid (%)	Ash (%)
FDC	25.3	18.3	4.3 ± 0.1de	72.3 ± 0.4h	10.6 ± 0.1b	5.7 ± 0.5a
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RAI-11	8.7	7.1	6.5 ± 0.1b	82.5 ± 0.2d	10.2 ± 0.1bc	2.0 ± 0.0d
RAI-12	8.0	5.9	10.1 ± 0.2a	73.7 ± 0.2g	13.1 ± 0.5a	2.3 ± 0.1d
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RPI-1	12.6	10.1	4.7 ± 0.1cd	87.8 ± 0.7b	6.1 ± 0.2d	3.8 ± 0.2b
RPI-2	11.6	9.7	3.4 ± 0.1e	83.2 ± 0.7e	7.4 ± 0.1c	3.2 ± 0.1c
RPI-3	14.1	11.1	2.3 ± 1.5ef	79.1 ± 0.5f	5.6 ± 0.1d	3.2 ± 0.3c
RPI-4	13.4	10.6	5.0 ± 1.8c	79.6 ± 0.7f	6.3 ± 1.0d	3.0 ± 0.1c
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Casein	-	-	4.0 ± 0.2d	85.5 ± 0.0c	-	-
Hemoglobin	-	-	2.0 ± 0.0f	94.4 ± 0.4a	-	-

FDC freeze-dried concentrate; RAI-11 and RAI-12, roe alkaline insolubles after alkaline solubilization at pH 11 or 12 respectively. RPI-1 and RPI-2, roe protein isolate adjusting at pH 4.5 and 5.5, respectively, after alkaline solubilization at pH 11; RPI-3 and RPI-4, roe protein isolate adjusting at pH 4.5 and 5.5, respectively, after alkaline solubilization at pH 12
Data are given as mean values ± SD (n = 3)
Means with different letters within the same column are significantly different at P < 0.05 by Duncan’s multiple range test
-; not determined
^aYield is weight (g) of roe protein isolate obtained from 100 g of raw YTR
^bProtein yield (g) = yield x protein (%)

ISSN: 2234-1757