Lecture Notes in
POSTHARVEST FISHERIES
Mentor: DR. FRUFA L. MENDEZ
16 June 2024
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Blue Economy/Ocean Economy
According to the World Bank, the blue economy is the "sustainable use of ocean resources
Postharvest Fisheries for economic growth, improved livelihoods, and jobs while preserving the health of ocean
ecosystem."
European Commission defines it as "All economic activities related to oceans, seas and
Fishery Waste Utilization coasts. It covers a wide range of interlinked established and emerging sectors.
The Commonwealth of Nations considers it "an emerging concept which encourages
better stewardship of our ocean or 'blue' resources."
The Center for the Blue Economy says "it is now a widely used term around the world with
three related but distinct meanings- the overall contribution of the oceans to economies, the
need to address the environmental and ecological sustainability of the oceans, and the ocean
Rufa L. Mendez economy as a growth opportunity for both developed and developing countries."
Mentor
Date of Lecture: June 16, 2024 1
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https://www.sciencedirect.com/science/article/pii/S2666049022000421#f0005
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Lecture Notes in
POSTHARVEST FISHERIES
Mentor: DR. FRUFA L. MENDEZ
16 June 2024
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Fish “Waste” in PH Fish silage
• Fish bycatch –fish or any marine species caught unintentionally by a fishing method or gear that is
targeting certain species of fish. It may consist of other fish species, undersized or juvenile species
(although the catch of these must be prevented at all times), or even the same targeted species but of • liquid product made from whole fish or parts of
different sizes. Instead of discarding the bycatch, this can be used as raw material in the production of
fish silage (e.g. Ferraz De Arruda, Borghesi and Oetterer, 2007; Rattagol, Wongchinda and fish that are liquefied by the action of enzymes in
Swachatthanwongratana, 1980; Vazquez et al., 2011);
the fish in the presence of an added acid. The
enzymes break down fish proteins into smaller
• Seafood processing waste – Fish processing establishments produce a considerable amount of waste in
the form of trimmings such as heads, skin, tails and fins of fishes, the shells and heads of shrimp and
other crustaceans, gills and viscera. Some of these waste materials are processed into different
consumer food products, but the non-utilizable materials represent an environmental problem if
improperly discarded. The latter can be utilized in making fish silage (e.g. Haider et al., 2016; Hossain
soluble units, and the acid helps to speed up their
and Alam, 2016; Santos, Orejana and Bautista, 1978; Viana et al., 1996); activity while preventing bacterial spoilage
• Non-commercially important, non-indigenous species –different exotic or non-indigenous species that
have been introduced in some bodies of water in the Philippines (see Guerrero, 2014) and elsewhere • made from white fish offal does not contain much
oil, but when it is made from fatty fish like herring
(Simon and Townsend, 2003; Strayer, 2010). Some of these species have caused harm to the
environment by destroying the ecological balance and, to some extent, by endangering the native
population of some endogenous stocks (Simon and Townsend, 2003). Since research into their
utilization as an ingredient in fishmeal has already been conducted (Abarra et al., 2017; Bowzer,
Bergman and Trushenski, 2014; Fagbenro and Jauncey, 1998), these same species can likewise be used
it may be necessary to remove the oil at some
in fish silage processing, in order to make these ‘unwanted’ species more useful. stage
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Lecture Notes in
POSTHARVEST FISHERIES
Mentor: DR. FRUFA L. MENDEZ
16 June 2024
Silage Production
• Several acids can be used, either alone or in combination. Hydrochloric or
sulphuric acid can be used; they are reasonably cheap, but a lower pH is required
with these mineral acids than with some organic ones, and this means greater
corrosion problems, and the silage has to be neutralized before use. Formic acid,
an organic acid, is a good choice because preservation is achieved at a slightly
higher pH, it has some bacteriostatic action, and the silage need not be neutralized
before adding it to the feed, but it is more expensive than mineral acids
• The composition of fish silage is very similar to that of the material from which it is
made. A typical analysis of white fish offal is 80 percent water, 15 percent protein,
4·5 percent ash and 0·5 percent fat, and the composition of silage from offal is
https://www.fao.org/4/x5937e/x5937e01.htm virtually the same. Whole fatty fish like sprats and sand eels have a higher protein
and fat content, and correspondingly lower water and ash content.
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Toppe, J., Olsen, R.L., Peñarubia, O.R. & James, D.G. 2018.
Silage Production
Production and utilization of fish silage. A manual on how to
turn fish waste into profit and a valuable feed ingredient or
fertilizer. Rome, FAO. 28 pp.
• Samples from a batch of silage for analysis should be taken only after thorough
mixing to ensure that they are representative. Acidity should be measured when
making large batches; with formic acid the pH should be 3·6-4; if it is above 4 more
acid should be added; if it is below 3·8 less acid could probably have been used,
with a saving in cost. The exact amount of acid has to be found by experience, but
the proportion given earlier is a good guide.
• Fish silage of the correct acidity keeps at room temperature for at least two years
without putrefaction. The protein becomes more soluble, and the amount of free
fatty acid increases in any fish oil present during storage, but these changes are
unlikely to be significant nutritionally. Fish silage in any event would probably not
be stored commercially for more than about 6 months. Silage becomes smoother in
consistency during storage, and develops a pleasant malty odour.
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Lecture Notes in
POSTHARVEST FISHERIES
Mentor: DR. FRUFA L. MENDEZ
16 June 2024
Fish Protein Concentrate
• One of the earliest attempts to recover protein from by-products and under-utilized species for use as a
human food was the production of fish protein concentrates (FPC)
• Fish protein concentrates are produced by using chemical solvents and sometimes high temperatures to
extract and separate proteins from other components of the raw material (e.g., fat).
• The National Marine Fisheries Service (NMFS) in the US (then Bureau of Commercial Fisheries) initiated a
https://openknowledge.fao.org/server/api/c
large research program in this area in the early 1960s with the goal of finding ways to produce FPC on a large
scale to stimulate the US seafood industry and also fight the global protein malnutrition problem (Snyder,
ore/bitstreams/bca6b669-8736-4c2e-b002-
1967).
• Solvent extracted FPC (type-A FPC) is produced by extraction with isopropanol or azeotropic extraction with
2fe0a366c3cd/content
ethylene dichloride
• The raw material is ground and then extracted with isopropanol at 20–30oC for 50 minutes. The supernatant
is then collected and extracted two times, first at 75°C for 90 minutes with isopropanol and then at 75°C for
70 minutes with azeotropic isopropanol
• final supernatant fraction which is then dried, milled and screened to separate out bone pieces
• should be largely colorless and odorless and primarily consist of protein (<1% lipids) with high biological
value.
• Type-A FPC is poorly soluble or dispersible in foods, which greatly limits its applicability (Cheftel et
al., 1971; Mackie, 1974; Venugopal et al., 1996)
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GLEANINGS (workshop) Bangladesh
• For fish waste, heads and gills of large
fish are sold for human consumption.
Shrimp and fish entrails are sold to local
fish farmers through third parties to feed
farm fish, particularly African catfish
(Clarias gariepinus), Pangas catfish
(Pangasianodon hypophthalmus), tilapia
(Oreochromis spp.) and shrimp (Penaeus
spp.) and prawn (Macrobrachium spp.).
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Lecture Notes in
POSTHARVEST FISHERIES
Mentor: DR. FRUFA L. MENDEZ
16 June 2024
Philippines Thailand
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Thank you!
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