• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.598-605
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• 2010

This study investigated the physicochemical and enzymatic properties of unmarketable bastard halibut (Paralichthys olivaceus) cultured in different regions (i.e., Jeju, Wando, and Geoje) as a potential source of surimi and surimi gel. The proximate composition of unmarketable bastard halibut cultured in different regions did not differ significantly at P<0.05. Compared to Alaska pollock muscle, all of the unmarketable bastard halibut muscle had a 4% higher crude protein content and 5% lower moisture content. The collagen content of bastard halibut muscle cultured in Jeju was 1.96 g/100 g, which was higher than in fish cultured in other regions. Regardless of the region where cultured or pH, the enzymatic activities of the crude extracts from unmarketable bastard halibut muscle ranged from 0.30.0.48 U/mg for casein and hemoglobin, 11.9.13.7 U/mg for LeuPNA, 5.6.6.7 U/mg for ArgPNA, 2.8.4.7 U/mg for SAAPFNA, and 0.1.0.2 U/mg for BAPNA. Regardless of region, no mercury or lead was found in any of the unmarketable bastard halibut muscle, except for lead in fish cultured in Geoje. The strength of surimi gels from unmarketable bastard halibut cultured in Jeju, Geoje, and Wando was 1059, 988, and 900 g${\times}$cm, respectively. The surimi gel from unmarketable bastard halibut cultured in Jeju was stronger than commercial Alaska pollock surimi, which was grade SA.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.18-24
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• 2011

This study investigated the physicochemical and enzymatic properties of unmarketable cultured bastard halibut (Paralichthys olivaceus) of different weights as a potential source of surimi and surimi gel. The proximate composition of cultured bastard halibut of different weights did not differ significantly at P<0.05 (light weight (LBH) 400~500 g, medium weight (MBH) 600~800 g, and heavy weight (HBH) > 1,000 g). Compared to Alaska pollock muscle, the bastard halibut muscle had a 4% higher crude protein content and 6% lower moisture content. The collagen content of LBH bastard halibut muscle was 1.58 g/100 g, which was lower than or no different from bastard halibut weighing different amounts. Regardless of fish weight or pH, the enzymatic activities of crude fish extracts ranged from 0.34~0.48 U/mg for casein and hemoglobin, 11.0~12.7 U/mg for LeuPNA, 5.4~6.1 U/mg for ArgPNA, 2.3~2.9 U/mg for SAAPFNA, and 0.1~0.2 U/mg for BAPNA. The yield of surimi gel from LBH was 24.4%, which was similar to that from MBH and lower than that from HBH. The surimi gel from LBH was similar to that from HBH, while weaker than that from MBH. The surimi gel from LBH gel was stronger than grade SA gel from commercial Alaska pollock.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.2
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• pp.109-115
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• 2009

The properties of surimi gel from Olive flounder Paralichthys olivaceus were evaluated with addition of various food additives and by heating under different conditions. The optimum heating conditions for get good textured surimi gel from Olive flounder was 40 minutes at $85^{\circ}C$. Optimum texture characteristics such as hardness, cohesiveness, chewiness, gumminess and gel strength of olive flounder fish paste can be acquired by washing the paste 2 times and by adding sodium chloride (2.5%), sodium polyphosphate (0.3%) and starch (4%), respectively. Furthermore, we compared gel texture characteristics and strength of manufactured Olive flounder fish surimi with commercial Alaska pollack to determine their commercial applicability. Texture characteristics and gel strength of Olive flounder surimi were higher than those of the commercial Alaska pollack surimi. In addition, both lightness and whiteness were higher in surimi gel from Olive flounder than from the commercial Alaska pollack.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.3
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• pp.191-196
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• 2011

In this study, we investigated the chemical and enzymatic properties of unmarketable cultured bastard halibut (UCBH) Paralichthys olivaceus harvested at different times (March, May, July, September, November, and January), and we examined the physical properties of surimi gel from UCBH as a potential source of surimi and surimi gel. The moisture and crude protein contents of UCBH harvested in July and January were >78% and <19%, respectively, which is greater than the moisture content in UCBH harvested in May, March, and September, but lower than the crude protein content. Regardless of the month of harvest, the UCBH had a higher crude protein content than Alaska pollock, which is the largest fishery biomass used for surimi and surimi gel, but a lower moisture content. Regardless of the month of harvest, the enzymatic activity in crude extracts of UCBH muscle ranged from 0.31-0.59 U/mg for casein (pH 6.0 and 9.0) and 11.7-12.7 U/mg for LeuPNA. These findings suggest that autolytic enzymes were unaffected by gel formation. Gel strength was highest in the surimi gel prepared from UCBH harvested in September, November, and January; second highest in that prepared from UCBH harvested in March and May; and lowest in that prepared from UCBH harvested in July. Compared to the gel strength of surimi gel from grade SA commercial Alaska pollock surimi, the strength of the surimi gels prepared from UCBH harvested in March, May, September, November, and January were superior, whereas that of the surimi gel prepared from UCBH harvested in July was similar.

• Fisheries and Aquatic Sciences
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• v.22 no.9
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• pp.20.1-20.8
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• 2019

Background: Despite the favorable geo-climatic potential of Cameroon, the national production of tilapia remains low due to poor tilapia growth reported by fish farmers. One of the underlying reasons is the early female maturation at a very small size and precocious breeding in earthen ponds, resulting in overpopulation which leads to stunted growth and therefore to the production of unmarketable fish size. Studies have shown that dietary supplementation of G. kola enhanced growth in young Clarias gariepinus and Oreochromis niloticus. It was also reported that G. kola inhibited spawning in Tilapia adult females. Therefore, this study sought to assess the effects of Garcinia kola as growth promoter and inhibitor of gonadal development in young Oreochromis niloticus. Methods: A total of 108 juveniles weighing $13.32{\pm}0.62g$ were randomly distributed in 9 hapas of 12 fishes each (9 females and 3 males) and fed for 70 days with three isonitrogenous diets, 40% crude protein with increasing Garcinia kola supplementation levels of 0 (normal diet), 6% and 10% (experimental diets). Physico-chemical parameters of the water (temperature, dissolved oxygen, pH, nitrate, nitrite, ammonia, and transparency) were measured twice a week. Every 14 days, fish were harvested, counted, and weighed. At the end of the experiment, three fish of each sex per replicate were sacrificed and their gonad and liver collected and weighed. Data were statistically analyzed using one-way analysis of variance repeated measure followed by Newman-Keuls multiple tests. Results: The results showed that all physico-chemical parameters of the water were within the recommended values for Tilapia culture. Tilapia fed 6% Garcinia kola supplemented diet displayed higher final body weight in males ($38.60{\pm}3.50g$) and females ($36.77{\pm}3.62g$) compared to those receiving normal diet ($36.23{\pm}1.36g$ and $25.87{\pm}3.32g$; respectively to the final body weight in males and females). The gonadosomatic index and hepatosomatic index indicated no significant variation in males while in females, these were significantly low in the experimental fish compared to control fish. Conclusion: The results of this study demonstrated that supplementation of G. kola seeds in diets of young Tilapia improved growth performance and impaired gonadal development in females.