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

• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.197-201
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• 2014

This study was performed to identify and assess food hazards during dry laver processing. Samples including raw materials, intermediates, and finished products during dried-laver processing were collected from seven dried-laver processing facilities, and microbial analyses were conducted. Microbial levels such as total coliforms and total viable cell count (TVC) increased as the processing steps progressed. TVC and total coliforms ranged from <30 to $9.1{\times}10^7$ CFU/g and <18 to 27,600 MPN/100 g for intermediates and finished products obtained during dried-laver processing, respectively. However, no fecal coliform was detected in the samples. Additionally, food-borne bacteria including Bacillus cereus, Listeria monocytogenes, Salmonella sp., Staphylococcus aureus, and Vibrio parahaemolyticus were not identified in finished products. For heavy metal content, arsenic ranged from 30.18 to 39.05 mg/kg, mercury from 0.005 to 0.009 mg/kg, and cadmium from 0.076 to 0.318 mg/kg dry mass in all finished products. However, lead was not detected in samples tested in this study. In conclusion, dried-laver products were safe based on the levels of food-borne bacteria and heavy metal contents. However, it is important to reduce total viable cell counts and total coliforms during dried-laver processing.

• 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.

• Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.27-33
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• 2015

Seasoned laver Pyropia spp. is one of the most well-known Korean traditional seafoods, and is becoming more popular worldwide. Various mixed oils are used in the preparation of seasoned laver; however, there is no information available regarding the effects of the blending ratio of oils on the quality of seasoned laver. In this study, the effects of the blending ratio of corn, sesame, and perilla oils on the oxidation and sensory quality of seasoned laver were monitored and optimized using a response surface methodology. An increase in the proportion of corn and sesame oils resulted in an excellent oxidation induction time, whereas a high ratio of perilla oil reduced the thermal oxidative stability of the mixed oil. In the sensory test, the seasoned laver with the highest proportion of sesame oil was preferred. The optimal blending ratio (v/v) of corn, sesame, and perilla oils for both oxidation induction time ($Y_1$) and sensory score ($Y_2$) was 92.3, 6.0, and 1.7%. Under optimal conditions, the experimental values of $Y_1$ and $Y_2$ were $4.41{\pm}0.3h$ and $5.58{\pm}0.8$points, and were similar to the predicted values (4.34 h and 5.13 points). Our results for the monitoring and optimization of the blending ratio provide useful information for seasoned laver processing companies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.5
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• pp.510-517
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• 2018

The study investigated the seasonal and regional changes in the food components of raw laver Pyropia sp.. Samples were obtained monthly from December 2017 to March 2018 at auction markets located in Gangseo-gu, Busan (Nakdong-raw laver), Seocheon-gun, Chungnam, Wando-gun, Jeonnam and Goheung-gun, Jeonnam. The general components, heavy metals and minerals, free amino acids, total phenolic compounds (TPC), and antioxidant activities of the samples were analyzed. No significant physicochemical changes in the moisture, crude lipid, and ash contents were observed in the raw lavers tested. However, the crude protein content of Nakdong-raw laver was the highest in December 2017 at $7.20{\pm}0.28%$ and the content was higher seasonally and regionally than those of the other raw lavers. In addition, the taurine, zinc, manganese and TPC contents of Nakdong-raw laver was higher seasonally and regionally than those of the other raw lavers. The ethanolic extract of Nakdong-raw laver also had higher antioxidant activity, including as DPPH (2,2'-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis [3-ethylbenzothiazoline-6-sulphonic acid]) radical scavenging activity, although there was no significant correlation between TPC and the antioxidant activity. This study is the first analysis of seasonal and regional changes in the major food components of raw laver cultivated in Korea.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.3
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• pp.383-389
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• 2005

In this study, we analyzed consumers' extra willingness-to-pay for the organic farmed laver, which recently is related to the increased interests in health. Survey questionnaires, which are targeted the urban consumers and based on the equivalent surplus concept, were intended to calculate extra willingness-to-pay for the organic farmed laver. Payment card format was used as the questionnaires type and tobit model was used for the analysis. Variables used for the analysis are sex, age, region, occupation, number in family and income. The results were that the consumers had extra willness-to-pay of 17.16% on average for the eco-friendly organic farmed laver. The higher the income and the more the family number, the customers had more extra willingness-to-pay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.585-590
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• 2016

The objective of this study was to develop an export determinant model for laver in the producing district. The annual and monthly amounts of laver products, local price, export price, and foreign exchange rate were included as explanatory variables. The estimation showed that the laver export is influenced more by the long term rather than short term product increase. In addition, as the foreign exchange rate and export price increase, the quantities exported decrease elastically. On the other hand, as the price in the local market increases, the quantities exported decrease non-elastically. Therefore, to enhance the laver exports, it is important to establish infrastructure for long term production increase, forecast and provide information on the export price and foreign exchange rate more accurately.

• 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 the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.10-16
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• 1997

To confirm the possibility of seaweed extracts for functional food, water or ethyl alcohol solubles were extracted from laver, Porphyra yezoensis and evaluated those food components such as proteins, carbohydrates, nucleic acids, taurine, pigments and browning extent. The amount of proteins, polysaccharides and nucleic acids extracted decreased with increasing ethyl alcohol concentration, which was maximal when water was used as extraction solvent. The extractability of proteins, polysaccharides and nucleic acids was different between the dried and the roasted laver. Taurine was extracted about 1% from the dried and the roasted laver in the range of o~7o% ethyl alcohol concentration. The amount of carotenoids extracted by 95% ethyl alcohol from the dried and the roasted laver were 146.6 and 138.4mg%, respectively, which was 66 ~ 80% of yield extracted by methanol/acetone(1/1) solvent. The browning value of 50 ~6o% ethyl alcohol extraction group from roasted laver was highest among water/ethyl alcohol extraction group. The extraction yield was maximum when laver was extracted with water, and the value was 26.3% for the dried laver and 27.5% for the roasted layer. Organoleptic characteristics from four kinds of extraction groups containing hot water extraction showed that extracts from the roasted laver were evaluated most eminent and thought to be applicable to various preparation of food.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.579-588
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• 2001

In order to investigate the composition and monthly variation of extractive nitrogenous components in the laver Porphyra dentata cultured at the south coast of Korea, the fresh laver was analyzed separately for the amounts of free amino acids, combined amino acids, ATP and its related compounds, and quaternary ammonium basis in fresh laver were measured. The extractive nitrogen contents of fresh laver extracts were 760~870 mg/100g (dry basis). Twenty-seven to thirty-one kinds of free amino acids were detected in the laver extracts and their total amounts were 2,404~3,966 mg/100g (on dry basis). The laver extracts showed rich in free amino acids such as alanine, taurine, glutamic acid, glutamine and aspartic acid. Sixteen to twenty-three kinds of combined amino acids were detected in the extracts and their total amounts were 1,429~2,692 mg/100g (on dry basis). Proline, glutamic acid, glycine, phosphoserine, serine were the amin combined amino acids in the extracts. The amounts of ATP and related compounds were 73.3~94.4 mg/100 g (2.04~4.43 $\mu$mol/g, on dry basis). Homarine and trigonelline were detected in all specimens but $\beta$-alaninebetaine, ${\gamma}$-butyrobetaine were found in some. Small amounts of trimethylamine were detected in all samples. Free and combined amino acids were occupying almost 90% of extractive nitrogen. Most of free and combined amino acids showed a marked monthly variation with a maximum in January and March, and a minimum in February and April. The fresh laver P. dentata did not differ much from the fresh laver P. yezoensis in qualitative com-position of extractive components, but their contents were generally low level.