| Summary: | 碩士 === 國立中興大學 === 動物科學系所 === 96 === The aim of this study was to investigate the functional characteristics of enzymatic hydrolysates obtained from waste chicken feet of broiler and silky fowl, which were gathered from local chicken processing factory. The feet of broiler and silky fowl were hydrolyzed by Alcalase, Flavourzyme, or Protease N for 12 hours. The hydrolysates were collected every 2 hours for analyzing the change of pH value, soluble protein, peptide content, antioxidative activity and ACE inhibitory activity. The hydrolysates with the highest ACE inhibitory activity were fractionated into 3-5 kDa, 1-3 kDa and below 1 kDa in molecular weight by ultrafiltration. After lyophilized, the fractions with different molecular weights were orally administered, respectively, in spontaneously hypertensive rats (SHR) at various doses of 10, 50 and 100 mg/kg for determining the decrease of immediate systolic blood pressure (SBP) in SHRs. And the fraction with potent antihypertension was analyzed the amino acid sequences of peptides within by LC/MS/MS.
The result showed that hydrolysis with Protease N for 12h had the highest peptide content (broiler feet: 42.93 mg/mL; silky fowl feet: 36.60 mg/mL) in both feet of broiler and silky fowl. In antioxidative activity, the hydrolysates obtained from broiler and silky fowl feet by hydrolysis with Protease N possessed better DPPH and superoxide anion radicals scavenging activity than other proteases. Moreover, the best antioxidative activity was found in a hydrolysate treated with Protease N for 4h in broiler feet (DPPH: 72.07%, SOD: 83.66%, p < 0.05), while the 2nd hour hydrolysate with the best activity (DPPH: 81.65%, SOD: 79.42%, p< 0.05) was observed in silky fowl feet. Beside, the hydrolysate from silky fowl feet revealed the higher activity on inhibition of lipid peroxidation than that of broiler feet. Also hydrolysis with Protease N had strong ACE inhibitory activity in both broiler and silky fowl feet, especially, the strongest one was found at the 4th hour hydrolysate in broiler feet (BP4, IC50 = 2.10 mg/mL) and at the 2nd hour hydrolysate in silky fowl feet (SP2, IC50 =1.09 mg/mL). After oral administration ( < 1 kDa, 100 mg/kg) in SHRs, both of BP4 and SP2 showed significantly effect on reducing immediate SBP of SHRs (p < 0.05), and the maximal reducing of 17 mmHg in SBP was obtained in SP2. Analysis of amino acid composition and sequences in peptides indicated that many hydrophobic amino acids residues were observed in SP2, including Val, Ile, Leu, Met, Phe and Cys. Especially Val was the highest quantities among them. These results suggested that potent antioxidative and antihypertensive effects in SP2 seemed to be contributed from peptides with large amounts of hydrophobic amino acids residues and Val.
|
|---|
