Antioxidant Properties Of Porcine Blood Hydrolysates

Porcine blood hydrolysates, haemoglobin hydrolysates and plasma hydrolysates were prepared through hydrolysis by papain, pepsin and trypsin, AS1398 protease and Alcalase, trypsin followed by flavourzyme, AS1398 protease followed by flavourzyme and Alcalase followed by flavourzyme. The antioxidant properties, including antioxidant activity in a linoleic acid system(AL), DPPH radical scavenging activity (DRSA), and ferrous ion chelating power(FICP), of the hydrolysates were evaluated. Futhermore, porcine plasma hydrolysates prepared with pepsin (PPE) were purified and investigated. The applications in soybean power and fish power were studied.The antioxidant activity in a linoleic acid system of hydrolysis, depending on the enzymes and substrates, was different. The exhibited most hydrolysis had excellent AL compared with blank(P<0.01). In the porcine blood hydrolysates, AL of hydrolysates of AS1398 digested porcine proteins (AP) was the most significant at the concentration of 10μg/mL, whose induction period was 7.15 times of the blank. Both AP and hydrolysate of trypsin followed by flavourzyme digested porcine proteins (TFP) showed the highest AL, which were 8.09 times higher than that of blank at the concentration of 100μg/mL. In the porcine haemoglobin hydrolysates, AL of trypsin (TFH) was the most notable at the concentration of 10μg/mL, whose induction period was 6.9 times of the blank. Alcalase followed by flavourzyme digested porcine haemoglobin (AFH) exhibited the most significant AL, which was 9.89 times stronger that of blank at the concentration of 100μg/mL. However, papain digested porcine haemoglobin (PAH) existed to promote lipid oxidation. In the porcine plasma hydrolysates, all of PPE, porcine plasma hydrolysates by papain (PPA) and porcine plasma hydrolysates by AS1398 followed by flavourzyme (PASF) presented the same AL, which was better than others were 8.09 times higher than that of blank at the concentration of 100μg/mL. Nevertheless, porcine plasma hydrolysates by trypsin (PT) had no effect on AL.DPPH radical scavenging activity of hydrolysates, depending on the enzymes and substrates, was various. Some showed certain DRSA. In the porcine blood hydrolysates, DRSA of hydrolysis were less than 5% and15%-25% mainly, at the concentration of 10μg/mL and 100μg/mL respectively. Apart from AS1398 digested porcine proteins (ASP) ,which was weak, only 28.9%. Other hydrolysis of DRSA exceeded 50% and pepsin digested porcine proteins, up to 75.5%, was the best. In the porcine haemoglobin hydrolysates, DRSA of hydrolysates was similar to that of blood at the concentration of 10μg/mL. Meanwhile which mainly was 30% to 50% except pepsin digested porcine haemoglobin (PEH) at 100μg/mL, and AS1398 followed by flavourzyme digested porcine haemoglobin (ASH) owned the highest DRSA with 49.56%. In addition, their DRSA were 45% to 50% and PPE embodied the strongest with 48.4% at 500μg/mL.FICP of hydrolysates changed with the enzymes and substrates and partially hydrolyzed with metal-ion chelating ability. Both ASFH and porcine plasma hydrolysates by AS1398 (PAS) indicated FICP over 50% at the concentration of 100μg/mL, but which was less than that of 10μM EDTA in 10μM FeCl2 system. ASP and ASFH resulted the highest FICP in blood and haemoglobin hydrolysates, respectively, they were 1.47, 2.18 times stronger than that of the 10μM EDTA in 50μM FeCl2 system. Both PTF and PAS presented the strongest FICP of 2.6 times that of the 10μM EDTA, besides, FICP of PPE was 1.5 times that of 10μM EDTA. Generally, there was no linear relationship between FICP and the concentration of Fe2+.The hydrolyates, the indexes of LA, DRSA and FICP, at different concentrations were analyzed . In addition, PPE had good antioxidant activity without heme.PPE was separated by resource 15RPC column and Superdex peptide 10/300GL column and antioxidant activity between the peptides and polar and relationship to molecular weight were analyzed. According to the results of protein composition analysis , we divided the hydrolysates into four groups by resource 15RPC, including R1 and R2, R3 and R4, and their hydrophobicities were ranging from weak to strong, while we divided the hydrolysates into three groups by Superdex peptide 10/300GL, containing S1 (MW: 7000u-12000u), S2 (MW: 3000u-7000u), S3 (MW: 1000u-3000u). The results showed that AL was significantly and positively correlated to the relative amount of R1, S2 and S3. This study revealed that DRSA was dependent on R3 and S1. The fractions of PPE were not responsible for FICP.The antioxidant properties, including acid value and peroxide value, of PPE in application of soybean meal and fish meal at 0.05% added concentration were investigated. PPE showed good antioxidant activities, corresponding to BHT, at the same addition to applied system.