Short-term retrogradation behaviour of corn starch is inhibited by the addition of porcine plasma protein hydrolysates.

The potential inhibition of porcine plasma protein hydrolysates (PPPH) on the short-term retrogradation of corn starch (CS) was investigated. Compared with native CS, PPPH significantly enhanced breakdown and decreased the total setback in a rapid visco analyser (RVA) measurement (P < 0.05). Dynamic time sweep analysis of pre-prepared gelatinized samples showed a decrease in the storage modulus (G') and increase in the loss tangent (tan δ) in the presence of PPPH. Differential scanning calorimetry results showed that PPPH significantly reduced the gelatinization enthalpies (ΔHg) and retrogradation enthalpies (ΔHr) of CS (P < 0.05). Fourier transform infrared spectroscopy analysis indicated that the addition of PPPH decreased the amount of hydrogen bonds within starch. Low field nuclear magnetic resonance results showed that the addition of PPPH has an important role in increasing the mobility of water molecules and blocking the short-term retrogradation of CS. X-ray diffraction results showed that the peaks at 2θ close to 17-18° were progressively decreased to smaller angles with increasing PPPH concentrations. This phenomenon indicated that PPPH could interact with amylose and cause lattice distortion, which reduced the starch retrogradation. The results demonstrate that the addition of PPPH plays a crucial role in interfering with short-term retrogradation of CS.