Functional properties of protein isolate obtained from physic nut (<Emphasis Type="Italic">Jatropha curcas</Emphasis> L.) seed cake

Physic nut (Jatropha curcas L.) protein isolate was successfully achieved from physic nut seed cake by an alkaline extraction and followed by an isoelectric precipitation. The protein isolate had small amounts of phorbol esters, phytic acid, and saponin without any lectin. Its minimum and maximum solubility were at pH 4.0 and 12.0, respectively. Its water and oil binding capacities were 3.22 g water/g protein and 1.86mL oil/g protein, respectively. Its foaming capacity and emulsion activity showed high values in a range of basic pHs. Its foaming and emulsion stability values decreased with increasing time and exhibited high levels under basic pH conditions. Physic nut protein isolate had unique functional properties in water binding capacity, emulsion activity, and emulsion stability indicating an important role in food systems. It may be applied to salad dressing, mayonnaise, sausage, and meat products. Therefore, physic nut seed cake has a potential to be exploited as a novel source of functional protein for food or feed applications.     

Toxic Compound, Anti-Nutritional Factors and Functional Properties of Protein Isolated from Detoxified Jatropha curcas Seed Cake

Jatropha curcas is a multipurpose tree, which has potential as an alternative source for biodiesel. All of its parts can also be used for human food, animal feed, fertilizer, fuel and traditional medicine. J. curcas seed cake is a low-value by-product obtained from biodiesel production. The seed cake, however, has a high amount of protein, with the presence of a main toxic compound: phorbol esters as well as anti-nutritional factors: trypsin inhibitors, phytic acid, lectin and saponin. The objective of this work was to detoxify J. curcas seed cake and study the toxin, anti-nutritional factors and also functional properties of the protein isolated from the detoxified seed cake. The yield of protein isolate was approximately 70.9%. The protein isolate was obtained without a detectable level of phorbol esters. The solubility of the protein isolate was maximal at pH 12.0 and minimal at pH 4.0. The water and oil binding capacities of the protein isolate were 1.76 g water/g protein and 1.07 mL oil/g protein, respectively. The foam capacity and stability, including emulsion activity and stability of protein isolate, had higher values in a range of basic pHs, while foam and emulsion stabilities decreased with increasing time. The results suggest that the detoxified J. curcas seed cake has potential to be exploited as a novel source of functional protein for food applications.     

Toxic Compound,Anti-Nutritional Factors and Functional Properties of Protein Isolated from Detoxified Jatropha curcas Seed Cake

Jatropha curcas is a multipurpose tree, which has potential as an alternative source for biodiesel. All of its parts can also be used for human food, animal feed, fertilizer, fuel and traditional medicine. J. curcas seed cake is a low-value by-product obtained from biodiesel production. The seed cake, however, has a high amount of protein, with the presence of a main toxic compound: phorbol esters as well as anti-nutritional factors: trypsin inhibitors, phytic acid, lectin and saponin. The objective of this work was to detoxify J. curcas seed cake and study the toxin, anti-nutritional factors and also functional properties of the protein isolated from the detoxified seed cake. The yield of protein isolate was approximately 70.9%. The protein isolate was obtained without a detectable level of phorbol esters. The solubility of the protein isolate was maximal at pH 12.0 and minimal at pH 4.0. The water and oil binding capacities of the protein isolate were 1.76 g water/g protein and 1.07 mL oil/g protein, respectively. The foam capacity and stability, including emulsion activity and stability of protein isolate, had higher values in a range of basic pHs, while foam and emulsion stabilities decreased with increasing time. The results suggest that the detoxified J. curcas seed cake has potential to be exploited as a novel source of functional protein for food applications.     

Functional properties of proteins isolated from phorbol ester-free physic nut (Jatropha curcas L.) seed cake

Phorbol ester-free physic nut (Jatropha curcas L.) seed cake is a nutritious protein source. Functional properties of the protein isolates obtained from various protein precipitation methods were investigated. Proteins isolated from the seed cake by ammonium sulfate gave the highest yield. The solubility of all proteins increased with increasing pH with their maximum and minimum solubility at pH of 12.0 and 4.0, respectively. The protein prepared by ethanol provided the maximum water holding capacity (3.34 mL water/g protein). The oil binding capacities of all proteins were 1.96–2.03 mL oil/g protein. The protein precipitated by ethanol showed higher emulsion activity and stability than that precipitated by acetone and ammonium sulfate. The protein obtained from ammonium sulfate gave the highest foam capacity, while the protein from acetone had the highest foam stability. Different functional properties of the proteins were achieved by various protein precipitation methods. The protein isolate obtained from each method could serve as a food ingredient applied to food products requiring a specific functional property.