Evaluation Method Of Edible Bird's Nest

Objective:Edible bird's nest(EBN)is built essentially by swiftlets of Collocalia spp.(Apodidae)during the breeding season from gelatinous saliva to form "nest cement".The swiftlets are mainly found in Southeast Asia and islands and around the Pacific and Indian Oceans.Most of the bird's nest are collected from Cliffs and has been described as a very dangerous occupation with many health hazards,making bird's nest one of the most expensive foods in the world.Due to high economic value and scarce natural authentic bird's nest,commercially processed bird's adulteration on the market is prevalent.Commonly used adulterants include pork skin,sodium alginate,isinglass,agar and jelly fungus.This study was aimed at seeking specific and reliable,yet simple and convenient,analytical methods for the identification and authentication of natural raw unprocessed bird's nest and commercially available bird's nest from different origins.To establish the quality of bird's nest using water soluble capacity,protein content,monosaccharide,polysaccharides,amino acids,and sialic acid composition in bird's nest to explore different types and origins of bird's nest and its common adulterants to determine the difference in quality and establish quality standards for commercially available bird nest.Methods:Water soluble capacity test was used to authenticate raw edible bird's nest and processed EBN.To compare the nutritional components in the various EBN,Kjeldahl method was applied for the colorimetric detection and quantification of total proteins whiles the Amino acid analyzer was employed for the determination of the total amino acids composition in natural edible bird's nest,commercially available EBN,processed EBN and adulterants from different origins.Phenol-sulphuric acid method was used to determine the polysaccharide content in edible bird's nest and adulterants.A simple high performance ion liquid chromatography with pulsed amperometric detector(HPAE-PAD)was employed to simultaneously analyze monosaccharide and sialic acid content of natural edible bird's nests,processed products and adulterants.Results:Water soluble capacity test results indicate that the bird's nest expansion ratio is five times higher than the expansion rate of the edible bird's nest concentrates/processed EBN and the adulterants.Bird's nest protein content was determined by the Kjeldahl method because it is simple,reliable and easy to operate.The results indicate that the protein content in natural unprocessed bird's nest is greater ranging from 45%up to 60%,as compared to the relatively low levels of processed bird's nest and adulterants.Bird's nest compositional analysis revealed 17 kinds of amino acids with total amino acids content of 53.77%(up to 62.99%)of which histidine was the highest content,with 7.21%.There were differences between the different groups compared,Malaysia bird's nest were slightly higher than that from Indonesia,Vietnam's bird's nest had a total amino acid content in the range of 33.85%to 60.31%.The proportion of Aspartic,Leucine,Tyrosine,Glutamic acid,Valine,Serine,Phenylalanine,Histidine,and Proline in genuine bird's nest is high;to which Glutamic acid makes up about 5%and Histidine making up 6%to 12.24%.The total polysaccharide content in bird's nest was 1.5%.There were significant differences in the total content of amino acids between different groups of edible bird's nest.The results from the HPAE-PAD method for the determination of monosaccharide indicate higher proportions of Galactosamine(GalN),Glucosamine(GlcN),Galactose(Gal)and Sialic Acid.Galactosamine(GalN),Galactose(Gal)were absent in tremella white fungus,however tremella white fungus mainly contained Fucose(Fuc),glucose(Glu)and Mannose(Man)with Mannose accounting for the highest proportion of up to 26.95%.Glucose(Glu)was the lowest in the bird's nest samples but higher in processed bird's nest pulp.Conclusion:The examination of expansion rate between the natural raw bird's nest products,processed bird's nest from different origins and adulterants can primarily be used for identification and authentication of bird's nest.Determination of protein content in natural bird's nest,processed bird's nest and adulterants reveals that the protein content differs in origin and bird's nest product type.Total amino acids and most of the single amino acid other than glycine,alanine,methionine and proline content differ between different origins and product type.Monosaccharide type and polysaccharide content differ between genuine and fake edible bird's nest.Different types and origins of Edible bird's nest sialic acid content did not show any significant difference.From the results,it can be suggested that water soluble capacity,protein content,amino acid composition,monosaccharide,polysaccharide and sialic acid content can be used as indicators as evaluation criteria for Edible bird's nest.