Production and characterization of proteins from mechanically deboned turkey residue
Abstract
The main objectives of this investigation were to determine appropriate methods for recovering proteins from mechanically deboned turkey residue (MDTR), investigating their characteristics and functionality, and recommending their potential uses in human nutrition. The first protein extracts were recovered by alkali extraction. The protein solution was either concentrated by ultrafiltration and dried, or precipitated with acid and dried. The protein yields for the latter methods were 22% and 15%, respectively. These proteins were yellow in color and had BET monolayer values of 3.8 and 4.5 g water/g, respectively. They had poor functional properties, especially their solubility in water, but they had good nutritional qualities (chemical score (CS) = 0.94; essential amino acid index (EAAI) = 1.29). Thus they can be used potentially in comminuted poultry products as protein substitutes. Three grades of gelatin were also produced from the MDTR following the alkali extraction process. The process produced 31 g proteins/g MDTR. All the gelatins had high mineral and protein contents and high intrinsic viscosities. They were very soluble in hot water. They formed gels but their gel strengths were lower than that of a commercial gelatin sample. They contained mainly high molecular weight proteins and their molecular weight distribution was similar to that of a commercial gelatin sample. They had poor functional properties and nutritional quality (CS = 0.34, 0.31 and 0.32). They can be used in products such as sauce thickeners and in the manufacture of edible films, based on their good gelling properties. The third protein extract produced from the MDTR was a protein hydrolysate using papain. The hydrolysate was highly soluble in water at room temperature over a wide pH range ($>$90%), was comprised mainly of amino acids and short peptides, and was rich in the minerals calcium, magnesium, phosphorous, zinc and iron. It had a high buffering capacity, but a low nutritional quality (CS = 0.54; EAAI = 0.81). However, it can be thermally processed and used as a high protein diet supplement, or in the manufacture of sports, medical, hypoallergenic or other similar diets due to their high solubility and high content of amino acid and short peptides.
Degree
Ph.D.
Advisors
Singh, Purdue University.
Subject Area
Food science
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