Effects of preparation and drying methods on the antioxidant activity of enzymatically hydrolyzed porcine placenta hydrolysates

Porcine placenta was hydrolyzed using papain and trypsin in a combined formulation. An orthogonal experimental design (L9(3)4) was applied in order to obtain porcine placenta hydrolysates (PPH) having the best antioxidant activities. The PPH was dried using vacuum drying (VD), spray drying (SD), and freeze drying (FD) and the effects of these drying methods on the antioxidative activity and solubility were investigated. The DPPH scavenging activity of these PPH reached 44.450.46% and the molecular weight of 83.39% of these PPH peptides was below 3000Da. The proportion of highly antioxidative amino acid residues in these PPH reached 60.14%. The VD-PPH showed the lowest antioxidantive activities (DPPH, superoxide and hydroxyl radical scavenging activities, and lecithin liposome antioxidant activity) and the lowest solubility. The FD-PPH exhibited the highest antioxidative properties and the highest solubility. Both the antioxidative properties and the solubility of SD-PPH remained in between those of FD-PPH and VD-PPH. Spray drying can be a method of choice to produce PPH powders due to its higher throughput.