Comparison of Protein Chemical and Physicochemical Properties of Rapeseed Cruciferin with Those of Soybean Glycinin

Abstract

Rapeseeds contain cruciferin (11S globulin), napin (2S albumin), and oleosin (oil body protein) as major seed proteins. The effects of oil expression and drying conditions on the extraction of these proteins from rapeseed meal were examined. The conditions strongly affected the extraction of oleosin and only weakly affected the extraction of cruciferin and napin. The protein chemical and physicochemical properties of cruciferin, the major protein present, were compared with those of glycinin (soybean 11S globulin) under various conditions. In general, cruciferin exhibited higher surface hydrophobicity, lower thermal stability, and lower and higher solubility at mu= 0.5 and mu = 0.08, respectively, than did glycinin. At the pHs (6.0, 7.6, and 9.0) and ionic strengths (mu= 0.08 and 0.5) examined, the emulsifying ability of cruciferin was worse than that of glycinin, except at mu= 0.08 and pH 7.6. The emulsifying abilities of cruciferin and glycinin did not correlate with thermal stability and surface hydrophobicity. Higher protein concentration, higher heating temperature, higher pH, and lower ionic strength were observed to produce harder gels from cruciferin. Gel hardness partly correlated with the structural stability of cruciferin.

Physicochemical and Functional Characterization of Cocosin, the Coconut 11S Globulin

“…However, the solubility rapidly decreased below pH 5.4 with a minimum solubility of 10.2% observed at pH 3.4. This trend is also observed with other 11S globulins from soybean and rapeseed (Mohamad Ramlan et al, 2002). correlated the solubility of wild-type and mutant soybean 11S globulins with the amount of acidic amino acids present.…”

“…The U-shaped solubility profile of cocosin at µ=0.08 is also typical for most food proteins, with minimum solubility occurring at the isoelectric pH (Damodaran, 1996). The 11S globulins from the wild-type and mutant cultivars of soybean (Mori et al, 2004;Rickert et al, 2004) as well as cruciferin (Mohamad Ramlan et al, 2002) also exhibited similar low solubility profiles at acidic pH due to isoelectric precipitation.…”

“…In particular, the 35 kDa polypeptide was completely digested after only 5 min of reaction, as shown by the complete disappearance of the This particular behavior of cocosin is contrary to what was observed for other 11S globulins, in particular for glycinin and cruciferin. Better emulsifying ability was exhibited by glycinin and cruciferin when the ionic strength (µ=0.5) or salt concentration was high (Mohamad Ramlan et al, 2002). On the other hand, sunflower total seed proteins also had similar emulsifying characteristic as coconut globulins and protein concentrate (Venktesh and Prakash, 1993).…”

Structural Properties of Cruciferin and Napin of Brassica napus (Canola) Show Distinct Responses to Changes in pH and Temperature

“…However, the opposing nature of structural and structure-related properties may not be advantageous when protein products that are mixtures of cruciferin and napin and their functionalities are considered. These inherent differences of the consisting protein types may explain the differences in functionalities observed between canola protein isolates and legume proteins such as soy [ 58 ], in which mostly glycinin (12S legumin) and β-conglycinin (7S vicilin) predominate. Also, it should be noted that B. napus contains napin protein which is different than cruciferin in many ways and having unique properties that deserve separate attention for recovery and subsequent uses.…”

How biomass composition determines protein extractability

“…The globulin properties of legumes differ from each other. Soybean's globulin (named as glycinin), e.g., has lower surface hydrophobicity compare to rapeseed's globulin (named as cruciferin) (Mohamad Ramlan et al, 2002). With this, soybean's globulin is easier to solubilize than rapeseed's globulin, leading to higher protein extraction yields.…”