Page 51 - New additives and ingredients in the formulation of aquafeeds

the protein isolates, must interact with the soluble proteins to remain until
the final stages of that process, accumulating in the final atomized product.
Anyway, depending on the values observed ​of the fatty acid composition
of these protein products, these may be supplemented with the needs of
aquaculture diets formulation and reduced the inclusion of fish oil, making
the final product formulation more profitable from an economic point of
view (Table 2) (Nasopoulou and Zabetakis, 2012).
Table 2. Fatty acid compositions of protein isolates and hydrolysates obtained in
pilot plant from chickpea and lupin
Chickpea
Isolate
Chickpea
Hydrolysate Lupin Isolate Lupin
Hydrolysate
16:0 (Palmitic acid) 14.95 ± 0.07 13.20 ± 0.04 13.33 ± 0.01 13.15 ± 0.03
16:1 (Palmitoleic acid) 0.24 ± 0.01 n.d n.d. n.d.
18:0 (Stearic acid) 1.56 ± 0.05 1.68 ± 0.00 6.80 ± 0.14 6.70 ± 0.01
18:1 (Oleic acid) 23.15 ± 0.08 24.48 ± 0.12 37.05 ± 0.27 35.02 ± 0.02
18:2 (Linoleic acid) 57.36 ± 0.02 55.48 ± 0.18 38.45 ± 0.42 38.08 ± 0.09
18:3 (Linolenic acid) 2.37 ± 0.05 2.36 ± 0.01 3.74 ± 0.05 3.84 ± 0.01
20:0 (Arachidic acid) 0.36 ± 0.03 0.62 ± 0.01 0.09 ± 0.02 0.70 ± 0.01
22:0 (Behenic acid) 0.07 ± 0.00 0.60 ± 0.11 0.17 ± 0.05 1.66 ± 0.09
Results are expressed in percentage as mean ± standard deviation of three different determinations
n.d.: no detected
It is also noted that due to the hydrolytic process developed, a free amino
acid fraction around 15% is obtained. In this sense, a high free amino acid
content between 10 and 20% of the total protein amino acids is found in
natural marine environments (phytoplankton and zooplankton), which
appears to be important in the initial stages of growth of marine fish
since some of them have an attractant function (Ronnestad et al., 2003).
In freshwater environments the free amino acid content, (although) even
though is smaller, is important as well, being about 5% of total amino acids
(Ronnestad et al., 2003). In this sense and considering the levels of free
amino acids found in different hydrolysates, they may have an advantage
of applicability comparing with the protein isolates from which they come
from and, attending the results obtained, the hydrolytic process could be
modulated depending on the final application. Few studies have been made
in this regard and there is no general pattern, being the free amino acid
stimulation-dependent of each species (Kasumyan and Doping, 2003). Non-
polar amino acids seem to have a greater preference for a wider range of
species. amino acid as leucine and phenylalanine are in a high concentration
in the chickpea and lupin protein hydrolysates due to the exoprotease used
(Flavourzyme), and it could be beneficial for this purpose.
Plant protein isolates and hydrolysates as alternative to the animal protein in aquaculture diets 49