Investigation on the Chemical Consitituents and Flavor of Algae- and Diet-fed Small Abalones

• Main Authors: Meng Meei Lay, 賴孟美
• Other Authors: 邱思魁
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/02624537764634487208

碩士 === 國立海洋大學 === 食品科學系 === 87 === Small abalone (Haliotis diversicolor) is an important cultured shellfish in Taiwan. Because the artificial propagation and formulated feeds have been successfully developed, the production of small abalone increase significantly in recent years. The purpose of this study is to compare the differences in chemical composition between algae-fed and diet-fed small abalone. In addition, the changes in chemical constituents by different seasons, storage and heating were also studied. The results of this study can provide basic data for market promotion and seafood processing. Results by preference test of organoleptic evaluation showed that the cooked meat of diet-fed small abalone had better taste than that of the algae-fed group. It was found that the former had higher amounts of glutamic acid (Glu), glycine (Gly), alanine (Ala), ATP and related components (ARC), glycogen, and glycinebetaine. However, the latter had higher amounts of taurine (Tau) and homarine. As for the cooked viscera, the total amounts of free amino acids (FAA) in two groups were similar. The algae-fed abalone had higher amount of phosphoserine, but the Gly was lower. In addition, the algae-fed small abalone had much more amount of glycogen. The abalone with higher glycogen content in the muscle showed a lower amount of glycogen in the viscera. There was no significant difference in the amounts of glycinebetaine, homarine, and trigonelline between two groups. The algae-fed small abalone contained higher amount of moisture in the muscle than diet-fed small abalone, but the latter had significantly higher amounts of crude protein and fat. In March and December, the algae-fed small abalone had a higher amount of FAA, especially for the Tau. The total amounts of ARC were higher in samples of March and July, and the glycogen were higher in January, March and July. As compared to algae-fed small abalone, the diet-fed small abalone had a higher amount of FAA in July and December. In addition, the total amounts of ARC and glycogen are higher in July and March. The results of FAA, ARC and glycogen were generally consistent with the fact that the small abalone was more tasty in the spring and winter seasons. As for the viscera, the total amount of FAA was higher in May and August, but the ARC was higher in January and July. The algae-fed group had a higher amount of glycogen in the muscle from January to May; however, the diet-fed group had a higher amount from October and January and in July. In conclusion, the taste components in the viscera were higher in the spring and summer seasons. The total amount of FAA in the muscle decreased after heating for both groups, especially for the glutamine and Ala. The total FAA decreased by 14% and 30% in the algae- and diet-fed group, respectively. However, the total amount of ARC changed little in the heating process. For individual compounds, the levels of ATP and ADP decreased, but the AMP and Hx increased. On the other hand, the glycogen in the viscera decreased by 23%. In conclusions, the total amount of ARC changed significantly in both the muscle and viscera during heating. The changes of FAA, glycogen, and ARC in the viscera were more significant than the muscle. During storage at 5, 15 and 25℃, the amount of FAA was increased by 17, 23 and 24%, respectively. The FAA including Tau, Glu, Gly, Ala, and Arg increased more significantly than other FAA. The amount of ARC was increased during storage. In the early storage, the degradation rates of ATP and ADP were 15≧25＞5℃, but that of AMP was 5＞15＞25℃. The glycogen and pH value also decreased during storage. The VBN value increased gradually with the time, and the value of 9 mg/100g was proposed as the limit of initial decomposition. The Kc value of 16 ~ 17% for small abalone was the limit of acceptability as well.