The effect of pretreated method to remove the non-collagenous protein by using alkaline and enzyme Alcalase, as well as the temperature and time for extracting on the properties of gelatin from tra catfish skin were investigated. Yields of gelatin extracted at 70 °C for 1h from pretreated skin by enzyme method (16.2%) was significantly higher than that of the sample by alkaline method (12.14%). However, the gel strength of gelatin from skin treated via enzyme Alcalase was lower than gelatin sample pretreated by alkaline while the turbidity values was higher than gelatin from skin pretreated via alkaline. From SDS-PAGE profile, gelatin from skin pretreated by alkaline consisted of two different α- chains in protein pattern while enzymatic gelatin had low molecular weight peptides. The FT-IR spectra showed the lower wavenumber in amide I and III of enzymatic gelatin in compare to alkaline gelatin by the loss of triple helical structure during enzyme treatment. From the results, the using enzyme for pretreated material has potential to replace the alkaline method for gelatin production with purpose to reduce chemical waste caused serious ecological issues.

In this study, the lipid properties of tra catfish flesh meat (Pangasianodon hypophthalmus) during refrigerator storage as well as the properties of oil extracted from tra catfish flesh meat were investigated. The quality of the samples was maintained, with lipid content and peroxide value falling within the acceptable range after 15 days of storage. The yield of oil extracted using isopropanol:hexane at a ratio of 2:3 was higher (56.2%) than that extracted using ethanol:hexane at a different ratio. Isopropanol:hexane (2:3) also showed the highest L* (lightness/brightness) value (33.35) and the lowest b* (yellowness/blueness) value (7.35). The polyunsaturated fatty acid levels as well as the omega 3 and 6 fatty acid levels of oil were highest in this solvent at a ratio of 2:3. Thus, tra catfish flesh meat could be used as a material for lipid extraction.

The effect of methods to remove protein content on the properties of glucosamine hydrochloride from the shells of white leg shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeus monodon) was investigated. Chitin from shrimp shells was obtained by demineralization in 6% HCl for 12h, deproteinization by two different methods (first group soaked in 8% NaOH for 36h and second group treated in Alcalase enzyme at the concentration of 0.2% for 36h). Two group samples were converted to glucosamine hydrochloride by soaking in 36.76% HCl solution for 5h at 85 °C. The results of fourier transform infrared spectroscopy (FTIR), solubility and recovery yield analysis showed that deproteinization methods did not significantly affect the properties of glucosamine hydrochloride. However, glucosamine hydrochloride from white leg shrimp shells contained higher recovery yield and solubility than black tiger shrimp shells.

This study aimed to identify the properties of gelatin extracted from snakehead fish (Channa striata) by-products, including scale and a mixture of skin and scale. The gelatin extraction yield from fish scales was lower than that from fish skin and scales. Both gelatins showed similar gel strength (248 g in the mixture of fish skin and scale and 245 g in fish scale gelatin), while the viscosity and color of samples from fish skin and scale were better than those of fish scale samples extracted at 80 °C for 1 h. SDS-PAGE profile of fish scale protein degradation correlated with the increasing wavelength in amide I and III. Thus, a mixture of skin and scale can be used as a raw material in gelatin production.