• Korean Journal of Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.19-30
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• 1968

An experiment on the culture of laver, Porphyra tenera, was carried out from September 26, 1965 to February 12, 1966 at a laver farm on the coast of Gae-do, Hwacheong-myeon, Yeocheon-gun, Jeonranam-do, using 'Sae-ol-bal' (triple-knotted blind) laver bed, resulting in the following data: 1. 'Sae-ol-bal' laver, bed was less destroyed compared to ordinary (dual knotted blind) laver bed, the destruction rate being $9.8\%$ in 'Sae-ol-bal' laver bed, while $35.3\%$ in ordinary laver bed (Table 5). 2. The quantity of laver yield is the greatest on the edge-part, the next on the basal part, and the smallest on the middle part of the 'Sae-ol-bal' laver bed (Table 6, Figs. $7\~8$). 3. The ordinary laver bed may yield better harvest on the calm farm but 'Sae-ol-bal' laver bed yields better harvest at a farm where the destruction of bed is remarkable by wind and wave action.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.346-349
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• 2018

In North-East asian countries, laver cultivation has been an important marine industry in coastal areas as well as fishery because laver (Porphyra) is nutrient-rich food and has been used in many Asian cuisines. Laver is characterized by high concentrations of fiber and minerals, a low fat content, and, in some cases, relatively high protein levels. In this paper we inplimented design of fully automatic laver harvesting, nowdays most peoples are used to collect a laver harvesting by human, it is very defficult working, due to wind, waves, and the weather conditions which is hard to stand on the ship and holding the seaweed nets it can be injurced human, this is the reason to we are developed automatic harvesting method, in this project we proposed automatic harvesting collect method which is operated without human. Mainly we design and developed automated ship, This ship is devided in to three parts frist part is supporting roller, second part is drum screener, thried part is lifting mechanism. Thise are operated with hydro pnumatic equimpment, this divice are control with micro controller. The system prototype has implemented and satisfied by the performance to realize the further level.

• Journal of Environmental Science International
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• v.16 no.8
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• pp.897-906
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• 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 the Korean Society of Fisheries and Ocean Technology
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• v.59 no.3
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• pp.215-220
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• 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 Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.394-402
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• 2001

In order to investigate the composition of dried layer, Porphyra yezoensis cultured at the south coast of Korea, the dried laver was analyzed separately for extractive nitrogen, free and combined amino acids, ATP and related compounds and quaternary ammonium basis using specimens collected monthly from January to April 1998. The extractive nitrogen contents of dried layer extracts were $976\~1,196\;mg/100\;g$ (on dry basis). Twenty-eight to thirty-one kinds of free amino acids were found in the dried laver extracts and their total amounts were 5,648-6,845 mg/100 g (on dry basis). The extracts were rich in free amino acids such as alanine, glutamic acid, taurine, phosphoserine and aspartic acid. Eighteen to twenty-two kinds of combined amino acids from oligopeptides were found in the extracts and their total amounts were $1,194\~1,406\;mg/100\;g$ (on dry basis). The amounts of ATP and related compounds were $111.6\~195.5\;mg/100\;g\;(3.30\~6.00{\mu}mol/g$ on dry basis). Homarine was detected in all samples but glycinebetaine, $\beta$-alaninebetaine and $\gamma$-butyrobetaine disappeared during processing, TMAO was detected in all samples but low TMA was found in some. During processing of dried layer, P. yezoensis, free amino acids, ATP and its related compounds were increased but the other constituents such as combined amino acids, TMAO and TMA and betaines were decreased in all specimens.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.403-411
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• 2001

In order to investigate the composition of dried layer, Porphyra dentata cultured at the south coast of Korea, the dried layer was analyzed for extractive nitrogen, free amino acids, combined amino acids, ATP and its related compounds and quaternary ammonium basis, The extractive nitrogen contents of dried laver extracts were 670-1,304 mg/100 g (on dry basis). From twenty-eight to twenty-nine kinds of free amino acids were found in the dried laver extracts and their total amounts were $2,796\~6,277\;mg/100\;g$ (on dry basis). The extracts were rich in free amino acids such as alanine, taurine, glutamic acid, glutamine and phosphoserine, From eighteen to twenty-one kinds of combined amino acids were found in the extracts and their total amounts were $1,406\~2,142\;mg/100\;g$ (on dry basis). The amounts of ATP and its related compounds were $65.7\~124,7\;mg/100\;g(2.13\sim3.68{\mu}mol/g$ on dry basis), Homarine was detected in all samples but $\beta$-alaninebetaine, $\gamma$-bufobetaine and trigonelline disappeared during processing. TMAO and TMA were detected in all samples. During processing of dried layer, free amino acids, TMAO and TMA were increased but the other constituents such as combined amino acids, ATP and its related compounds and betaines were decreased in all specimens.

• Food Science and Preservation
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• v.23 no.1
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• pp.139-143
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• 2016

This study investigated the effect of electron beam (EB) treatment on the microbial reduction of dried laver (Porphyra tenera) and identified EB-resistant bacteria from the treated dried laver. After EB treatments of 4 kGy and 7 kGy, the numbers of total bacteria and EB-resistant bacteria were measured using tryptic soy agar and mannitol salt agar, respectively. The morphological and biochemical characteristics of each isolated EB-resistant bacteria were investigated and these bacteria were identified. Compared to the control ($1.5{\pm}0.2){\times}10^6CFU/g$, the total bacterial number was significantly decreased to ($5.4{\pm}0.5){\times}10^4CFU/g$ and ($1.1{\pm}0.6){\times}10^4CFU/g$ after EB treatments of 4 kGy and 7 kGy, respectively. With a higher EB dosage, the number of red colonies was almost same, whereas the number of yellow colonies was significantly decreased to ($3.3{\pm}1.2){\times}10^3CFU/g$ and 0 CFU/g for 4 kGy and 7 kGy, respectively. All red and yellow colonies were gram-positive cocci, catalase-positive, and resistant to 3% and 5% NaCl media. From the 16S rDNA sequence analysis, yellow and red colonies were identified as either Micrococcus flavus or M. luteus, with 99% similarity for the yellow colonies, and Deinococcus proteolyticus and D. piscis, with 99% and 97% similarity for the red colonies, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.31-36
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• 1975

A combination of two specifically different pigments, phycoerythrine and chlorophyll, gives the laver shining black color. This shining black color is the dominant factor in deciding tile quality of the dried product of laver (dried laver). Therefore, this experiment was carried out to know the effect of tannic acid as a pigment fixing agent. Raw laver, Porphyra spp., was treated with tannic acid solutions to prevent dissolution of biliproteins especially phycoerythrine in to the fresh water. This danger is mostly revealed when the chopped and shredded lavers are suspended in fresh water before the laver sheets are finally made. The influence of mechanical damage with different diameters of chopper plate on dissolution of the pigment was also mentioned. Theresultsobtainedareasfollows: 1. When the raw laver not yet chopped was stored for 3 days at $1\~5^{\circ}C$ in a dark place, the contents of chlorophyll and phycoerythrine decreased. 2. In the organoleptic test (Table 2,3,4),: the dried laver with a good coloration and surface gloss was obtained from a chopper plate with 7 mm or 3 mm. 3. A tannic acid solution of $0.02\%$ and $0.004\%$ appeared effective In preventing dissolution of phycoerythrine.

• Preventive Nutrition and Food Science
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• v.18 no.2
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• pp.139-144
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• 2013

Laver, a red algae belonging to the genus Porphyra, is one of the most widely consumed edible seaweeds. The most popular commercial dried laver species, P. tenera and P. haitanensis, were collected from Korea and China, respectively, and evaluated for proximate composition, amino acids, minerals, trace heavy metals, and color. The moisture and ash contents of P. tenera and P. haitanensis ranged from 3.66~6.74% and 8.78~9.07%, respectively; crude lipid and protein contents were 1.96~2.25% and 32.16~36.88%, respectively. Dried lavers were found to be a good source of amino acids, such as asparagine, isoleucine, leucine, and taurine, and ${\gamma}$-aminobutyric acid. K, Ca, Mg, Na, P, I, Fe, and Se minerals were selected for analysis. A clear regional variation existed in the amino acid, mineral, and trace metal contents of lavers. Regular consumption of lavers may have heath benefits because they are relatively low in fat and high in protein, and contain functional amino acids and minerals.

• Korean Journal of Food Science and Technology
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• v.49 no.1
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• pp.20-27
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• 2017

Eighteen commercial laver (Porphyra sp.) products were purchased from Korean market and were monitored for their microbial contamination, pre-decontamination, and luminescence properties. The laver samples showed considerable variation in their microbial contamination, from $10-10^7CFU/g$ of total aerobic counts, <$10-10^2CFU/g$ of coliforms in 4 dried laver samples, and <$10-10^6CFU/g$ of yeasts and molds except in 3 samples. In addition, $10^2CFU/g$ of Bacillus cereus was found in one sample. DEFT/APC analysis was suitable for demonstrating whether the samples were pre-decontaminated or not, with DEFT/APC values lower than 2.0 log for non-heated samples and 1.0-8.5 log for heatprocessed samples. In photostimulated luminescence (PSL) calibration, 15 samples irradiated at 1 kGy showed positive (irradiated) values more than 5000 PCs. Furthermore, thermoluminescence (TL) analysis by separating the marker minerals from samples revealed the potential to be employed in identifying irradiation status by determining $1^{st}$ TL glow at $125-175^{\circ}C$ and TL ratio ($TL_1/TL_2$) of all the samples.