PROPERTIES OF GELATIN EXTRACTED FROM THE SKIN OF FRESHWATER FISH AND ITS EFFECT AS AN ANTIMICROBIAL AND ANTIOXIDANT
Abstract: Over the last years, considerable research has been conducted to develop and apply edible films and coatings made from a variety of agricultural commodities and/or wastes of food product industrialization. Such biopolymers include polysaccharides, proteins, and their blends. These materials present the possibility of being carriers of different additives, such as antimicrobial, antioxidant, nutraceuticals, and flavorings agents. In particular, the use of edibles films and coatings containing antimicrobials has demonstrated to be a useful tool as a stress factor to protect foodstuff against spoilage flora and to decrease the risk of pathogen growth. The more commonly antimicrobials used are organic acids, chitosan, nisin, the lactoperoxidase system, and some plant extracts and their essential oils. For the selection of an antimicrobial, it must be considered the effectiveness against the target microorganism and also the possible interactions among the antimicrobial, the film-forming biopolymer, and other food components present. These interactions can modify the antimicrobial activity and the characteristics of the film being these key factors for the development of antimicrobial films and coatings.

The present study was carried out to evaluate the antimicrobial effect and antioxidant potential of some freshwater fish gelatins exemplified in (A) African catfish (Clarias gariepinus) and (B) common carp (Cyprinus carpio) with natural herbs exemplified in rosemary and thyme as edible films coatings to evaluate the quality and safety of shrimp samples (Penuaeus semisulcatus ) refrigerated at 4?C for 12 days.

Catfish and common carp skin gelatins were extracted, dried, grinded then freezed. Gelatin solutions prepared under the following conditions (7.5g of gelatin/105 ml distilled water (6.67% w/w) was mixed with1.5g glycerol and solubilized later in a water bath at 55?C for 30 minutes ). The gelatin solutions were then divided into sections A, B, RA(catfish gelatin solution +5% rosemary), TA(catfish gelatin solution +5% thyme), RB(carp gelatin solution +5% rosemary), TB(carp gelatin solution +5% thyme) and control without solution and then the filleted shrimp divided into 7 sections and every section put in its indeed solution and taken off for cocking on steam for 20 min and then the shrimp was ready to refrigerating store for 12 days at 4?C and analysis.
The present study was carried out in order to achieve the following main goals:

1- Fish gelatin yield % per kg of fish skin in both species.
2- Proximate chemical analysis of fresh fishes and extracted fish gelatins with different extracting conditions, also to establish the best extracting conditions for producing gelatin from the two fish species
3- Estimation of Arsenic, Lead, Copper, Zinc, Cadmium and Chromium content in fresh catfish and carp gelatins.
4- Determination of amino acid composition of gelatin from catfish and carp skins.
5- Physical tests performed on fish skin gelatins compared to bovine gelatin including viscosity, gel strength, milting point, setting point & setting time, foaming properties, WHC& FBC, color, clarity and odor.
6- Quality control chemical tests performed on the final product during the course of refrigerated storage including: pH, WHC, PV, TBA, lipid oxidation percentage, TVB-N and FFA.
7- Microbiological profiles of both fish gelatins and final shrimp products at different times of refrigerated storage with different processing parameters.
8- Sensory Evaluation Ranking Test of both fish gelatins jelly compare to bovine gelatin jelly and Sensory Evaluation Ranking Test of the refrigerated stored shrimps during the course of the present study the following main results were obtained.
During the course of the present study the following main results were obtained.
A-Chemical tests
Publication year 2015
Organization Name
Author(s) from ARC
Publication Type PhD Thesis
↑