Effect of porcine plasma protein hydrolysates on long-term retrogradation of corn starch

The potential effect of porcine plasma protein hydrolysates (PPPH) on the long-term retrogradation of corn starch (CS) was investigated. The differential scanning calorimetry results showed that PPPH significantly reduced the retrogradation enthalpies (ΔHr) of CS (P<0.05), obviously decreased the crystallization rate constant (k), and enhanced the Avrami exponent (n) (P<0.05). Low-field nuclear magnetic resonance analysis demonstrated that the spin-spin relaxation time (T₂) remarkably increased with increasing PPPH concentration during storage at 4°C for 28days (P<0.05). The X-ray diffraction results revealed that the relative crystallinity of retrograded CS decreased from 13.04% to 8.73% with the addition of PPPH. Fourier transform infrared spectroscopy analysis demonstrated that the addition of PPPH led to a decrease in hydrogen bonds within starch. The results demonstrated that the addition of PPPH apparently played a crucial role in retarding the long-term retrogradation of CS.