In is an effort by doing studies for

In the world, the amount of food
waste is increasing day by day despite there is an effort by doing studies for
reducing food waste. 1 According to the data of the European Community, 2000
million tonnes
of waste are disposed annually and 14% of these wastes constitute solid waste.
2 It is forethought that globally ~ 2500 million tonnes of food waste will be
generated by 2025, so wasting of food needs to be avoided, decreased, processed
and recycled to develop a sustainable circular economy. 3 Recently, different
types of studies are done for the selective use of the industrial and food
wastes and the main purpose of
these studies is to ensure that a food is used as efficiently as possible. 1
In food production firms, most of food wastes are not used and some part of
them are converted into products with lower economic value by using different
technologies. Solid wastes of food industries and firms are most important resources
of protein. 2


Collagen is a main structural fibrous
protein that contributes in the connective tissues and used for different types
of industrial applications. 4 The waste of food protein refers the waste
collagen waste as well as and gelatin waste because gelatin is produced from
collagen with denaturation process. In the National Formulary, gelatin is
described as a protein that is produced by partial hydrolysis of collagen which
is extracted from white connective tissues, bones and skins of animals. 5
According to the Food Chemicals Codex, gelatin is the product which is
extracted from the alkaline, acid, or enzymatic hydrolysis of collagen, and the
main protein component of the bones, skin, and connective tissues of animal
such as poultry and fish. 5 Gelatin which is came from a precursor of
acid-treated is named as Type A, whereas gelatin which is derived from an
process of alkali-treated is named as Type B. 5


Gelatin has a large range of
applications in food, cosmetic, pharmaceutical and photographic firms and industries
and it is used for stabilizing, thickening and gelling agent because it has
surface active properties. 6 In 1685, the first commercial gelatin production
has been in Holland and then England followed Holland with producing gelatin
about 1700. 5 In the United States, the first commercial gelatin production
was in Massachusetts in 1808. 5 It is used for improving the viscosity in
aqueous systems and for forming aqueous gels. 7 It has lots of useful properties
such as a characteristic rheology which means melt-in-the-mouth, thermo-reversibility
and an excellent flavor releasing. 7

Gelatin which is derived from
collagen is a denaturalized protein and it is generally extracted from bovine
or porcine skins and bones. 8 There is not any plant source of gelatin, and
there is not any chemical relationship between gelatin and other substances
named to vegetable gelatin, such as seaweed extracts. 5 Gelatin is generally
produced from pigs and bovines. In the world, the gelatin production was
estimated as 300 thousand metric tons and 46% of them was produced from
pigskin, 29.4% was produced from hides of bovines, 23.1% of was came from
bones, and 1.5% was came from other parts. 9


    2.1. Problem Statement


Turkey is a country which is
surrounded by three seas. Therefore, there are lots of hunting, production and
consumption of marine food especially fishes. The big part of fish can be waste
after processing and consuming. However, the fish waste still includes
important source of protein as well as collagen and gelatin. There is a problem
of wasting of fishes which are important sources of gelatin. In literature,
there are some articles about fish gelatin production. Generally, the fish
gelatin is produced from fish skin, scales and fins. However, gelatin from
these parts of fish can have fishy odour. 10 It is thought that the fish bone
will not lead odours problems when the fish bones are used for production of
gelatin. The solution of decreasing fish waste is producing fish gelatin by
using fish bone. Very limited amount of articles and researches are done about
gelatin production from fish bones. 1,8,11,12,13,14 Therefore, different
types of fishes should be tried and used for producing gelatin from fish bones to
get high yield gelatin with good features and to contribute for food science.


   2.2. Why is The Project Worth Doing


The significant amount of fishes is
hunted, grown and consumed all around the world. In Turkey, the total amount of
hunting and growing fish is 588715 tones in 2016. 15
The significant amount of these tones is coming from the bones weight of
fishes. The bones are used just for producing fish flour. This situation shows that
the considerable potential of gelatin can be produced from the fish
wastes.  If these bones are used for
producing gelatin, there can be adequate in food field.


The fish waste can be used for gelatin
production because the gelatin from warm-blooded animals is restricted in some
countries due to the transmission of bovine spongiform