Characterisation of protein-rich poultry by-products after hydrothermal process and enzymatic hydrolysis

  • José Nuno Gonçalves Machado (Student)

Student thesis: Master's Thesis


The processing of farm poultry leads to a significant production of chicken feathers, which are currently categorized as waste due to the lack of adequate recycling methods. To address this issue, a potential solution involving a series of procedures was explored, resulting in samples holding promise in positively affecting plant growth and soil composition. This thesis focused on investigating the presence and concentration of D-form amino acids in these resulting samples, as they can inhibit plant growth. Various procedures were developed to shed light on the D-form composition of the samples, including the use of Chiralpak ZWIX (-) column in conjunction with LC-QTOF-MS equipment to separate and detect D- and L-form amino acids. Additionally, an effective separation technique for D- and L-form amino acids was established using a 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization reagent to address challenges posed by overlapping peaks or inadequate separation of DL-amino acids. Furthermore, a robust purification method was developed to extract free amino acids from the samples using the solid phase extraction (SPE) procedure. Finally, both qualitative and quantitative techniques were employed to assess the presence and concentration of D-form amino acids in the samples. The findings validated the presence of D-form amino acids, including Gln, Pro, Phe, Met, Glu and Ser, in the resulting samples. Among these, D-Ser and D-Glu exhibited the highest concentrations, while D-Met showed the lowest concentration across all the samples.
Date of Award3 Oct 2023
Original languageEnglish
Awarding Institution
  • Universidade Católica Portuguesa
SupervisorYang Zou (Supervisor)


  • D-form amino acids
  • Chiralpak ZWIX (-) column
  • 6-aminoquinolyl-N- hydroxysuccinimidyl carbamate
  • Solid phase extraction


  • Mestrado em Engenharia Alimentar

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