Isolation and characterization of protein hydrolysate from tilapia (Oreochromis niloticus) by-products for potential application as fish flavouring
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Date
2019
Authors
Cherrie Mae J. Martinez
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Abstract
The processing of fish into various products result in the accumulation of a large amount of by-products such as heads and viscera. The proper disposal of these wastes poses environmental concerns. However, these by-products are proven to be rich in nutrients and bioactive properties that can be a good source of high nutritive value in food industry. This study aimed to ultimately minimize the fish processing waste disposal by using tilapia wastes as a source of proteolytic enzyme to produce protein hydrolysates. The enzymes were extracted from tilapia viscera by using acetone and were dried overnight. The pH of the dried powder was adjusted and subjected to dialysis. The dialyzed solution solution are purified by using ammonium sulphate precipitation followed by gel filtration. The crude and purified enzyme extracted was used for enzymatic hydrolysis under the same condition of pH=2.37 degrees celcius at 1% E/S ratio for 120 min and undergone centrifugation. The oven dried hydrolysate were tested for proximate composition degree of hydrolysis, protein solubility and qualitative test for amino acids. The purified protease extracted exhibits an activity of 66.54 U/mg while the crude proteases is 23.16 U/mg. the degrees of hydrolysis of the hydrolysate from purified and crude were found to be 8.50% and 17.13% respectively. Fish protein hydrolysates from crude enzyme yielded 93.85% while the hydrolysate from purified only yielded 58.57%. The protein content, fat, ash and moisture content of hydrolysate from crude enzyme and purified enzymes are 1.05%, 22.89%, 13.46+0.59%, 10.72+0.5% and 4.03% , 16.96%, 8.44+0.43%, 12.71+0.42% respectively. The protein hydrolysate from crude enzyme has the highest solubility at pH=5 to 6 while the protein hydrolysate from purified enzyme is at pH=4. This indicates that both protein hydrolysate were soluble at acidic condition.
Both hydrolysates were tested positive to have tyrosine, tryptophan, and cysteine crude enzyme without undergoing purification can be used as a substitute to commercial enzymes to produce protein hydrolysate. The presence of essential amino acids gives a space for hydrolysate from crude enzyme to be used as fish flavoring under more study.
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Research Subject Categories::NATURAL SCIENCES::Chemistry