• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.59 no.3
• /
• pp.215-220
• /
• 2023

This study developed and evaluated a load cell-based automatic weighing system for the automated harvesting of laver (Porphyra tenera) in seaweed aquaculture. The current manual harvesting process was compared with the load cell-based automated system, and quantitative measurements of time, distance, and weight were conducted. The results demonstrated that the load cell-based system reduced the unloading time and increased the throughput compared to the manual method. In addition, statistical analysis confirmed that there was no significant difference from the mean in the weight measurement obtained using the load cell-based system. Based on these findings, the load cell-based automatic weighing system holds potential for efficient production and transactions in laver cultivation, contributing to cost reduction and improving the quality of life for aquaculture workers.

• Korean Journal of Food Science and Technology
• /
• v.31 no.5
• /
• pp.1283-1288
• /
• 1999

Effect of drying methods, such as natural solar drying, hot air drying$(at\;60^{\circ}C\;and\;105^{\circ}C)$, vacuum drying and freeze drying methods, on the quality of laver were investigated to develop optimum processing conditions for preparation of laver powder. Appreciable amount of laver pigments such as chlorophyll, carotenoid and phycobilin were lost during washing and drying process. Their loss was affected significantly by the method of drying. Among the methods tested, high temperature air drying was the worst in retaining laver pigment, while freeze drying was the best. Loss of vitamin C which was in the range of 75-99% was also affected by the method of drying. Isotherms for laver powder shelved sigmoidal shape and monomolecular layer moisture content of both laver powder(Porphyra dentata and Porphyra tenera) determined by the BET equation was 6.30%(dry basis). Laver powders prepared with Porphyra dentata and classified with 50-, 80- and 100- mesh sieves showed monomodal size distribution with the high frequency at 110-120, 100-110 and $80\;{\mu}m$, respectively, which indicated that size or laver powder was homogeneous.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.8
• /
• pp.1097-1101
• /
• 2006

In this study, seven species of seaweeds (Sargassum horneri, Grateloupia filicina, Kjellmaniella crassifolia, Porphyra tenera, Ecklonia stolonifera, Scytosiphon lomentaria, Agarum cribrosum) from Gangwon coast were collected for antioxidative assays. The methanol soluble and insoluble (water soluble) fraction which were prepared from 75% methanol extraction were assayed by DPPH method and deoxyribose assay. The antioxidative activity of methanol soluble fraction of Agarum, Scytosiphon and Sargassum reached to 26.60%, 24.28% and 23.40%, respectively. The antioxidative activities of methanol insoluble fractions of the Kjellmaniella and Porphyra were assayed to 29.70% and 21.01% which were higher than methanol soluble fractions with the values of 9.26% and 8.66%, respectively. The results from DPPH assay and deoxyribose assay showed the methanol soluble fractions of Agarum and Sargassum have strong antioxidative activity. However the methanol insoluble (water soluble) fractions of seaweeds did not show any meaningful antioxidant activity excepted Kjellmaniella and Porphyra.

• Korean Journal of Food Science and Technology
• /
• v.32 no.2
• /
• pp.298-305
• /
• 2000

Laver noodles were prepared with composite flour containing various ratios of laver powder sifted through 100-mesh sieve and their cooking characteristics were evaluated. Farinograph test results with the composite flour showed that water absorption rate increased linearly as the content of laver powder increased from 2% to 8%, while dough stability decreased linearly with the laver content. Dough development time increased 2.65-3.75 times by adding laver powder. DSC endotherms indicated that onset temperature $(T_o)$, peak temperature $(T_p)$, and conclusion tempearture $(T_c)$ of composite flour starch gelatinization shifted to a higher temperatures as the laver powder content increased. Difference in laver species (e.g., Porphyra dentata and Porphyra tenera) did not affect dough characteristics and surface color of doughs and noodles made with composite flours. From the sensory evaluation test for noodles, a laver noodle containing 4% roasted Porphyra dentata was the most preferred among the noodles tested.

• Journal of Environmental Science International
• /
• v.16 no.8
• /
• pp.897-906
• /
• 2007

Effect of seawater temperature (temperature) on the production of anchovy, Engraulis japonica and laver, Porphyra tenera Kjellman, were investigated in the eastern part of South Sea of Korea (ESS). Bimonthly temperature data (Feb., Apr., Jun., Aug., Oct., Dec.) from 1980 to 2002 were collected from Korean Oceanographic Data Center (KODC) and monthly anchovy catch and laver production from 1980 to 2002 were used from published sources by the Ministry of Maritime Affairs & Fisheries, Korea. Effects of temperature on the two organisms were examined in four cases. In case of lower anchovy catch and higher laver production (1993), temperature during main spawning season of anchovy was about $0.2-0.6^{\circ}C$ lower than normal condition, and temperature during seed collecting season of laver in Namhaedo, Kojedo went down below $22.0^{\circ}C$. In case of higher anchovy catch and higher laver production (1995), optimum temperature for catch was formed in main fishing ground, temperature for seed collection was lower than $22.0^{\circ}C$, In case of lower anchovy catch and lower laver production (1996), temperature for spawning and catch was about $0.6-1.6^{\circ}C$ lower than normal condition, and temperature during seed collection in nursery was about $0.5-1.0^{\circ}C$ higher than optimum temperature for seed collection. In case of higher anchovy catch and lower laver production (1998), temperature during main fishing and spawning season was about $1.0-1.8^{\circ}C$ higher than normal condition, and temperature during laver seed collection in nursery was $1.5^{\circ}C$ higher than optimum temperature for seed collection.

• Journal of Food Hygiene and Safety
• /
• v.15 no.2
• /
• pp.88-94
• /
• 2000

The purpose of this presents is to investigate, using natural food extracts(Green tea; Camellia sinesis, Du'chung; Eucommia ulmoides Oliver, Eu sung cho; Houttuynia cordate Thunb, Sam back cho; Saurus Chinensis, Baek hwa sa seal oho; Oldenladia diffusa Roxb., Laver; Porphyra tenera, Sea mustard; Undaria pinnatifda and Sea staghorn; Condium fragile) and juices(Sweet pepper; Capsicum annuum var. angulosum, Kale; Brassia oleracea var. acephala, Cucumber; Cucumis sativus, Onion; Allium cepa, Tomato; Lycopericon esculentum, Maesil; Prunus mume, Plum; Prunus salicina and Grape; Vitis spp.), the effect of natural plant components on the nitrite-scavenging under the different levels of pH. From the above mentioned extracts and juices, the content of vitamin C was detected, containing 65.1∼77.1 mg/100g, at the highest level in the Green tea, and followed by vegetables and fruits in order. The nitrite scavenging effect of teas, medicinal plants, and seaweed extracts, in the reaction system under the condition of pH 1.2, were 57.0∼100%, 50.0∼100%, and 18.0∼99.0%, respectively. Especially, the nitrite was scavenged to the level of 100%1 when 10 ml of kale and 5 ml of maesil Juice

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.7 no.2
• /
• pp.63-68
• /
• 1974

The growth of sea weeds is greatly affected by the environmental conditions of ambient water. Especially nutrient salts in sea water function as a major factor to the growth of lavers, so that the content of inorganic substances in lavers could he a criterion for quality evaluation of lavers. In this experiment, the relation between the quality and the content of Zinc and Magnesium which are not only physiologically active and closely related with pigments such as chlorophll and phycobilins but also important in quantify is discussed if such a measurement to be an index for quality evaluation. Sixteen samples of layers were collected from three different culture farms, 7 from Jangrim-Busan, 6 from Wando-Jeon Nam, 3 from Hadong-Gyeong Nam, and classified into 3 quality grades to each farm and to whole samples by organoleptic test. Zinc and Magnesium were analyzed by atomic absorption spectrophotometry. For pigment analysis, chlorphyll was extracted with 85 percent acetone, filtered and the absorbance was measured at 660 nm and the residue was further extracted with phosphoric buffer solution to determine the optical density for phycobilins at 560 nm. The result showed that the total content of Zinc and Magnesium varied between the farms, but kept consistent with quality grades from the same farm. The Zinc content was correlated proportion- ally with the content of phycobilins, and Magnesium content in total ash could roughly represent the content of chlorophll except some examples in which the Magnesium content of chlorophyll-ext ractresiduewasexceptionallyhigher. In conclusion the contents of these metals provide an applicable index for quality judgment of lavers.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.39 no.spc1
• /
• pp.165-179
• /
• 2006

Food habits of the gavelin goby Acanthogobius hasta and the fine spot goby Chaeturichtys stigmatias populations were investigated in the Jangbong tidal flat near Incheon, Korea. Samples were taken monthly from November 1999 to January 2001. The gut contents of 248 gavelin gobies and 139 fine spot gobies were analyzed. The diet of the gavelin goby was dominated by the gammaridean amphipod Chitinomandibulum emargicoxa, the crabs Macrophthalmus japonicus and Ilyoplax pingi, the shrimp Exopalaemon carinicauda, the bivalve Raetellops pulchella and the macro-algae Porphyra tenera. On the other hand, the fine spot goby mainly feed on the shrimps Crangon affinis, Latreutes mucronatus, E. carinicauda and Alpheus japonicus, the gammaridean amphipods C. emargicoxa and Synchelidium miraculum, and the bivalve R. pulchella. A comparison between frequencies of occurrence and abundance of food items in the gut showed that crustaceans (gammaridean amphipods, crabs and shrimps) and bivalves were important foods for the two gobies. However, the main components of the gut contents were different between two species, though this was probably due to differences in spatial distribution patterns of gobies and their prey items. In conclusion, both the gavelin goby and the fine spot goby, despite being the related species and co-inhabiting the similar part of the tidal flat, had quite distinct food habits and low dietary overlap (Schoener's index: 0.4). These indicated that the two gobies are or were partitioning resources in space and time for maximum uitilization of available food.

• The Korean Journal of Food And Nutrition
• /
• v.26 no.3
• /
• pp.492-501
• /
• 2013

The purpose of this study was to compare the eating experience and preferences for seafood among elementary school students in Gyeonggi-do. A survey was carried out on 383 elementary school students. As for the eating experience of seafood, the students were aware of and had eaten 'Scomber japonics (Go-deung-eo) (96.3%)', 'Anadara broughtonii (Jo-gea) (95.8%)', 'Ommastrephes sloani pacificus (O-jing-eo) (98.7%)', 'Panulirus japonicus (Sea-ou) (98.4%)', 'Porphyra tenera (Gim) (99.5%)', 'Shrimp, soused (81.2%)', 'Eo-muk (98.7%)', and 'Anchovy, dried (98.7%)'. As for the preferences for seafood, 'like (67.6%)', 'fair (21.5%)', and 'dislike (7.3%)' were observed. Concerning the frequency of seafood consumption, 4th grade students showed higher frequency of '1~2/week' compared to others (p<0.05). 6th grade students showed higher frequency of '3~4/week' compared to others (p<0.05). In terms of preferable cooking methods for seafood, 'grilling (35.0%)', 'soup (23.0%)', and 'raw fish (19.8%)' were observed. Boys showed a higher preference for 'grilling', 'frying' and 'raw fish' compared to the girls (p<0.05). Girls showed a higher preference for 'soup', 'braising' and 'steaming' compared to the boys (p<0.05). As for the seafood intake by eating place, 'home (60.1%)', 'eating-out (18.3%)', and 'school lunch menus (12.8%)' were observed in that order. Therefore, in order to increase the consumption and intake of seafood, students should attempt to achieve proper intake though information of nutrition and consistent nutritional education.

• Plant Biotechnology Reports
• /
• v.4 no.1
• /
• pp.49-52
• /
• 2010

A DNA extraction method using Chelex 100 is widely used for bacteria, Chlamydomonas, and animal cell lines, but only rarely for plant materials due to the need for additional time-consuming and tedious steps. We have modified the Chelex 100 protocol and successfully developed a rapid and simple method of DNA extraction for efficient PCR-based detection of transgenes from a variety of transgenic plant and algal species. Our protocol consists of homogenizing plant tissue with a pestle, boiling the homogenized tissue in a microfuge tube with 5% Chelex 100 for 5 min, and centrifuging the boiled mixture. The supernatant, which is used for PCR analysis, was able to successfully amplify transgenes in transgenic tobacco, tomato, potato, Arabidopsis, rice, strawberry, Spirodela polyrhiza, Chlamydomonas, and Porphyra tenera. The entire DNA extraction procedure requires <15 min and is therefore comparable to that used for bacteria, Chlamydomonas, and animal cell lines.