Abstract

Off grade egg with egg yolk content of 50% higher than normal egg can be successfully used in processing of hydrolysate flavourings. Protein extrac­tion using ethanol with two different ratios of egg yolk: ethanol: water ( 1: 1: 1 and 1:5:2) was carried out. The egg yolk protein was hydrolysed with 3N and 5N HCI for 10 hours at 11 ()'C. The protein hydrolysate obtained was freeze­ dried. Studies showed that extraction using 1:5:2 ratio gave the highest protein content. The protein hydrolysate treated with 5N HCI gave the highest degree of hydrolysis. Sample of 1:5:2 - 5N had the highest degree of hydrolysis (78.8%),followed by sample of 1:1:1-5N (69.4%) and 1:5:2 - 3N (66.9%). Sensory evaluation results showed that sample of 1:5:2 - 3N produced the strongest aroma among the four samples studied. Aroma of egg yolk protein hydrolysate was similar to Brands Chicken Essence or Brovil Beef Extract. The presence of volatile compounds with amine chemical groups, alcohol, alkane, indole and phenol were detected using headspace Gas Chromatography.