title: Effects of preparation methods on protein and amino acid contents of various eggs available in Malaysian local markets.
abstract: BACKGROUND
  The effect of preparation methods (raw, half-boiled and hard-boiled) on protein and amino acid contents, as well as the protein quality (amino acid score) of regular, kampung and nutrient enriched Malaysian eggs was investigated.
  
  
  METHODS
  The protein content was determined using a semi-micro Kjeldahl method whereas the amino acid composition was determined using HPLC.
  
  
  RESULTS
  The protein content of raw regular, kampung and nutrient enriched eggs were 49.9 ±0.2%, 55.8 ±0.2% and 56.5 ±0.5%, respectively. The protein content of hard-boiled eggs of regular, kampung and nutrient enriched eggs was 56.8 ±0.1%, 54.7 ±0.1%, and 53.7 ±0.5%, while that for half-boiled eggs of regular, kampung and nutrient enriched eggs was 54.7 ±0.6%, 53.4 ±0.4%, and 55.1 ±0.7%, respectively. There were significant differences (p < 0.05) in protein and amino acid contents of half-boiled, hard-boiled as compared with raw samples, and valine was found as the limiting amino acid. It was found that there were significant differences (p < 0.05) of total amino score in regular, kampung and nutrient enriched eggs after heat treatments.Furthermore, hard-boiling (100°C) for 10 minutes and half-boiling (100°C) for 5 minutes affects the total amino score, which in turn alter the protein quality of the egg.
authors.affiliation: Laboratory of Molecular BioMedicine, Insitute of Bioscience, Universiti Putra Malaysia, Malaysia.
authors.forename: Maznah
authors.initials: M
authors.lastname: Ismail
authors.affiliation: Laboratory of Molecular BioMedicine, Insitute of Bioscience, Universiti Putra Malaysia, Malaysia.
authors.forename: Abdalbasit
authors.initials: A
authors.lastname: Mariod
authors.affiliation: Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Malaysia.
authors.forename: Sia Soh
authors.initials: SS
authors.lastname: Pin
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D002645:Chickens; D003296:Cooking / Q000379:methods*; D004044:Dietary Proteins / Q000032:analysis*; D004531:Eggs / Q000032:analysis*; D006358:Hot Temperature; D008296:Malaysia
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins