CONICET - Facultad de Ciencias Agropecuarias, Universidad Nacional de Cordoba, Cordoba, Argentina.
J Agric Food Chem. 2010 Apr 14;58(7):4434-9. doi: 10.1021/jf903426f.
Studies related to the functional and thermal properties of peanut proteins are limited if compared with other vegetable protein sources. The aim of this work was to study the thermal denaturation of peanut protein isolates (PPI) by DSC. The thermal profile of PPI showed two endothermic peaks (assigned to denaturation of arachin and conarachin fractions). The thermal stability of arachin and conarachin increased when water content decreased, and a critical water level was found for both fractions. The effect of protein denaturants was studied. Low contents of urea stabilized protein fractions, but lower T(d) values were found with increasing concentrations. DeltaH values of arachin were affected by urea. SDS affected DeltaH values and thermal stability of conarachin; the arachin fraction showed higher resistance to SDS-induced denaturation. DTT addition did not affect conarachin stability, although enthalpy values decreased significantly. On the other hand, arachin was greatly affected by DTT. In summary, thermal denaturation parameters of PPI were sensitive to water content, indicating that polar groups of arachin and conarachin contribute to structure stabilization. Urea addition mainly affected the structure of the arachin fraction, which was attributed to its higher surface hydrophobicity. Results obtained from SDS and DTT suggest that hydrophobic interactions and disulfide bonds play an important role in structure maintenance of arachin and conarachin.
与其他植物蛋白来源相比，有关花生蛋白功能和热性能的研究有限。本工作旨在通过差示扫描量热法（DSC）研究花生蛋白分离物（PPI）的热变性。PPI 的热谱显示出两个吸热峰（归因于 arachin 和 conarachin 分数的变性）。当含水量降低时，arachin 和 conarachin 的热稳定性增加，并且发现这两个分数都存在临界含水量。研究了蛋白质变性剂的影响。低浓度的尿素稳定了蛋白质分数，但随着浓度的增加，T(d)值降低。urea 对 arachin 的 DeltaH 值有影响。SDS 影响 conarachin 的 DeltaH 值和热稳定性；arachin 分数对 SDS 诱导的变性具有更高的抵抗力。DTT 的添加并不影响 conarachin 的稳定性，尽管焓值显著降低。另一方面，arachin 受 DTT 的影响很大。总之，PPI 的热变性参数对含水量敏感，表明 arachin 和 conarachin 的极性基团有助于结构稳定。尿素的添加主要影响 arachin 分数的结构，这归因于其较高的表面疏水性。SDS 和 DTT 的结果表明，疏水相互作用和二硫键在 arachin 和 conarachin 的结构维持中起着重要作用。
