Salted Yolk Forming Mechanism of Separated Yolk brining Process

Salted Yolk Forming Mechanism of Separated Yolk brining Process Dr Aluck Thipayarat Food Engineering Department King Mongkut’s University of Technology Thonburi Bangkok, Thailand E-mail: athipaya@yahoo.com “New Food Products Development” By VAFoST Ho Chi Minh City, Vietnam November 12-15, 2004 Rationale and Motivation Salted Eggs Salt Infiltration Lower aw of Egg Proteins Traditional Salted Egg Processes Brining or Coating Traditional Salted Egg Processes Brining or Coating Salted Albumen Salted Yolk Products derived from Salted Yolk Steamed buns Chinese-style cakes Moon cakes “Moji” cakes Traditional Salted Egg Processes Brining or Coating Salted Albumen Salted Yolk Alternative Salted Egg Yolk Process Albumen Other Food Industries Yolk Brining Process Salted Yolk Objectives • Investigate the separated yolk brining process • Describe physiochemical and textural alterations of salted yolks during brining • Propose a model of salted yolk formation Experimental Procedure -Moisture Content -Salt Content -Texture Duck Egg Yolk Brining Solution (35 %NaCl w/v) Temper ature: o Brining Solution (NaCl) 250 ml Sample Analysis Thailand patent pending: 040300104 Sampling Times: 3, 6, 12, 18, 24, Fig Salted yolk from the separated brining process using 35%w/v NaCl solution, 65oC for 24 hours Mechanism of Separated Yolk brining Process t=0 Before Brining Protein Lipid Lipoprotein Fresh Yolk Brining Time t  ClNa+ - Initial Stage of Brining + Salt n Concentratio gradient Brining Solution Yolk + + - + H2O - + + - - + Osmotic p r essu r e + t  + + - + Brining Time - +++ - + - + + +++ + - + ++++ + + - + - -+ + + Lipoprotein + H2O ClNa+ - +++ + - + + +- -+ - - + + + ++ + OilOff + - + - + - He -at Aggregation Gelation Denaturation Oil Exudation t =tT Fully-gelled Yolk Salt H2O + +  t = tT + - + + - + - - + + t - + - Brining Time + t ∞ Prolonged Brining Salt H2O + +  t = tT t  ∞ + - + + - + - - + + t - + - + Brining Time Conclusions  The proposed models described the macroscopic and microscopic mechanisms of salted yolk forming  The macroscopic brining model was able to explain the alteration of physiochemical and textual characteristics of brined yolk  The microscopic description was able to elucidate the gel forming process  Gelled texture was resulted from a series of lipoproteins gelation (denaturation, aggregation, and gelation) Thank You Fig The alteration of cooked salted yolk Figure Average Moisture Contents in Egg Yolks During Brining Process Figure Average Hardness in Egg Yolks During Brining Process Figure Average Salt Contents in Egg Yolks During Brining Process