Nutritional And Flavor Components Analysis Of Antarctic Krill And White Shrimp

The Antarctic krill distributes widely in Antarctic water area with great quantity. It is one of biotic resources with the largest numbers and great reproductive efficiencies. White shrimp, one of the three major farmed species, is known for its characters of thin shell, thick meat and productiveness. White shrimp has plenty of nutrients and good flavors, which makes it popular with consumers. Near shore water area of China has been over developed so far, which led to a bad consequence that marine fishery resources ha ve been deducted seriously. Therefore, a new kind of species must be developed to fulfill this growing demand. The Antarctic krill, which can be regarded as a potential provision resource for human being, is attached more and more importance recent years. Some research on its nutritional components has been done, at the same time, research on its flavor has been seldom reported. It is an urgent question that “Does the Antarctic krill have pleasant flavor and be brought to dining table as same as white shrimp in the future?” On these bases, this thesis did the following research.First, the compare of basic nutritional components and hydrolytic amino acids between Antarctic krill and white shrimp have been researched. Vitamin component of Antarctic krill is supplemented based on former research. The consistence and content of flavor in Antarctic krill and white shrimp are determined. The contribution of flavor is determined by the method of Taste Activity Value(TAV) and the palatable standard is evaluated by the method of Equivalent Umami Concentration(EUC). To evaluate the whole flavor level of Antarctic krill and white shrimp, the consistence and content of each flavor component in two shrimps are analyzed in a radar graph, which is regard as their flavor modes. The main results are as following:The analysis of nutrients in Antarctic krill and white shrimp: Basic nutritional components: the contents of water(82.42%), ash(5.16%), and fat(1.25%) in Antarctic krill are higher than white shrimp(79.6%, 1.65%, and 1.59%), while crude protein(15.72%) and total sugar(0.87%) of Antarctic krill are lower than white shrimp(19.01%, 1.46%). The Antarctic krill can be food resource for human the same as white shrimp with its character of high protein and low fat. Amino acids: the total content of amino acids(TAA) in Antarctic krill and white shrimp are approximate(513.59mg/g,537.61mg/g). Glutamic acid account for the most among the hydrolytic amino acid of Antarctic krill(69.45mg/g), and the least is cysteine(5.97mg/g). The content of essential amino acid(EAA) is 188.84mg/g, EAA/TAA is 36.77%. While the most abundant amino acid of white shrimp is Asp(50.54mg/g), and the least is cysteine(7mg/g). The EAA in white shrimp is 221.81mg/g, EAA/TAA is 41.26%. The essential amino acids indexes(EAAI) of Antarctic krill and white shrimp are 43.0 and 52.3 respectively. Based on amino acid score(AAS), Met + C ys is the first limiting amino acids of Antarctic krill, Val is the second limiting amino acid; while in white shrimp Val is the first limiting amino acid and Met+ C ys is the second limiting amino acids. The result of chemical scores(CS) of them is the same. This result shows that they are both short of these two amino acids. Fat-soluble vitamins: the content of vitamin A in Antarctic krill muscle is 10.05ug/100 g, which is lower than white shrimp(25.52ug/100g); the content of vitamin E is 26.01ug/100 g, which is higher than white shrimp(22.03ug/100g). Since vitamin A and E are beneficial to immune system and Antarctic krill consists plenty of vitamin E, it can be assumed that Antarctic krill and white shrimp can be dietary supple ment.The analysis of flavor components in Antarctic krill and white shrimp. Glutathione: glutathione in Antarctic krill is212mg/100 g, which is much higher than white shrimp. Since glutathione can thicken the flavor, it can be assumed that glutathione is the main contributor of Antarctic krill flavor. Flavor nucleotides: ATP、ADP、AMP、IMP、Hx R、Hx、GMP、Ad R can be found in Antarctic krill and white shrimp muscle. The content of flavor nucleotides in Antarctic krill muscle is 322.63mg/100 g, which is higher than white shrimp(280.77mg/100g). AMP is the most flavor nucleotide of Antarctic krill(209.07mg/100g), and it is IMP(124.97mg/100g) in white shrimp, and the least is GMP in both. The TAV of IMP, AMP are greater than 1 and value of GMP is less than 1 in both of them. The EUC of Antarctic krill and white shrimp are 3.65 and 3.61, respectively. Taken together, IMP and AMP are the major flavor nucleotides of them, and their palatable taste intensities are equal. Organic acids: tartaric acid, malic acid, citric acid and succinic acid exist in both of their muscles. The content of organic acid in Antarctic krill is 118.64mg/100 g, twice higher than white shrimp(53.66mg/100g). The most abundant organic acid in Antarctic krill is malic acid(66.14mg/100g), which is succinic acid(22.04mg/100g) in white shrimp. The TAV of tartaric acid and succinic acid are greater than 1. Succinic acid has palatable flavor, therefore, it is a prominent contributor to their flavor. Malic acid’s influence on flavor in Antarctic krill is greater than in white shrimp, in addition. Betaine: The contents of betaine in Antarctic krill and white shrimp are 10.45mg/g and 9.42mg/g; the TAV are 4.18 and 3.77; it can be assumed that betaine has an outstanding effects on Antarctic krill and white shrimp flavor. Trimethylamine N-oxide(TMAO): The contents of TMAO in Antarctic krill and white shrimp are178.12mg/100 gand 111.62mg/100 g. The TAV are 0.16 and 0.11, less than 1, which means that TMAO is not a major contributor of shrimp flavor, and it may coordinates with the flavor.Free amino acids and flavor mode: Amino acids: 16 kind of free amino acids are detected in both Antarctic krill and white shrimp muscle, Cys is not detected. The total contents are 616.88mg/100 g and 1276.61mg/100g; the contents of FAA are 171.22mg/100 g and 524.37mg/100g; the content of proline is the greatest in both of them. The obvious factors of flavor in Antarctic krill are glutamic acid, alanine, lysine and arginine; and they are glycine, alanine and arginine in white shrimp. Free amino acids make Antarctic krill and white shrimp possess palatable taste and sweet taste on some level. Taste mode: the total content of flavor components in Antarctic krill and white shrimp are 1480.08mg/100 g and 1802.52mg/100 g, and free amino acids takes the most in both. The rank of the contributions is the same in Antarctic krill and white shrimp, which is: organic acid, flavor nucleotides, betaine, free amino acid and TMAO. TMAO has hardly any effects on taste.