• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1278-1284
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• 2003

This study was carried out to investigate the optimum conditions for making “sponge cake” with addition of ingredient, laver powder, and the quality characteristics of a new sponge cake. The moisture contents of sponge cake with 2, 4, 6% laver powder did not change but with 8 and 10%, the moisture contents increased to 28.89% and 30.69%, respectively. While specific gravity increased to 0.674 (control 0.493) when 10% laver powder was added, but volume was decreased. Most abundant mineral was Ca, followed by Na, Fe, Mn, Cu and Zn. The crust color degree of sponge cake with laver powder showed low marks on L, a, b. The crumb color degree showed low marks on L, b while “a” degree redness indicated highest marks with 4% laver powder. When it was seen under the microscope, the air cell numbers were decreased but the cell size became bigger. More free amino acid was contained when the laver powder was added. L-glutamic acid, L-alanine, L-aspartic acid and L-leucine were the major free amino acids. Hardness, springiness, cohesiveness, gumminess, chewiness and resilience degree of sponge cake with addition of laver power were higher than those of control. The sensory evaluation indicated that addition of 2% laver powder enhanced most mouth feeling, appearance, hardness, moistness, flavor and overall acceptability.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.298-305
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• 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 Nutrition and Health
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• v.24 no.1
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• pp.40-47
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• 1991

To investigate a possible effect of pectinate(apple and carrot) and alginate (tangle or green laver) on blood pressure and sodium retention, male spontaneous hypertensive rats (SHR) were assigned to 5 different experimental groups and fed diets containing 5% dietary fiber and 1% NaCl for 3 weeks. Dietary fibers were provided from one of the followings : cellulose, freeze dried apple, carrot, tangle(Undardia pinnatifda) or green laver(Monostroma nitidium). Fecal sodium excretion did not change significantly among the groups, however, urinary sodium excretion was increased in groups fed either carrot. tangle or green laver compared to group fed cellulose. Sodium balance was also negative in groups fed either carrot, tangle or green laver. most effectively in green laver group. Blood pressure of groups fed apple. carrot. tangle or green laver were decreased, especially those of group fed tangle, compared to those of group fed cellulose. Dietary fiber containing alginate. such as tangle and green laver, might have cellular binding capacity to sodium so that increased urinary sodium excretion and decreased blood pressure occur.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.47-52
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• 2006

The cultural grounds of laver has been surveyed using SPOT-5 satellite images to calculate the facilities of laver cultivation area in the coastal waters of Korea 10m resolution multispectral images of SPOT-5 are adopted for the south area of Daebu Island, Hwaseong city to develop an automatic detection approach of laver nets that consists of the following: band difference technique, canny edge detector and morphological analysis. The satellite-based facilities number was relatively high as compared with the licensed number in 2005, 676,749 chaek and 572,745 chaek(柵, unit of measure for laver farm), respectively. The data could be applied to achieve a good harvest for laver seaweed growers and to control its national production keeping a stable market price for the government body.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.221-229
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• 2018

Various types of dried laver Pyropia yezoensis have been produced in response to increasing demand and other laver goods manufactured using different processing methods are continuously being developed. The dried laver used in this experiment was initially heated at $165^{\circ}C$ for 3 seconds, followed by second heating at a high temperature ($340-350^{\circ}C$) to increase the storage period and enhance taste and flavor. Nutrient analysis of each sample heated under three conditions revealed that the protein and lipid contents were highest in samples from D company, while the carbohydrate contents remained relatively stable. After storage for 10 weeks at room temperature, changes in the composition were evaluated. The results showed decrease in protein (30%-49%) and essential amino acid contents. During storage, the major unsaturated fatty acids contained in dried laver slightly changed to 53.4%-56.0% in the form of EPA, while saturated fatty acids slightly increased to 18.4%-22.6% in the form of palmitic acid. The variables derived from fatty acid composition, such as atherogenic and thrombogenic, and hypocholesterolemic/hypercholesterolemic dietary indices, and polyunsaturated fatty acids/saturated fatty acids ratio, also indicated reasonable levels of stability. However, the laver should be consumed within 2 months.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1017-1021
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• 2003

The chemical properties of porphyran from dried laver (Porphyra yezoensis) and decolored laver were measured. Dried laver contained 12.5% porphyran while decolored laver contained 12.3%. The chemical components of porphyran extracted from dried and decolored laver were examined. The content of total sugar was 64.5% and 63.7% on dry base, respectively, while that of sulfate was 17.6% and 16.9%, respectively. The content of 3,6-anhydrogalactose was 18.8% and 18.1%, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.362-368
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• 2018

There is increased consumer demand for roasted seasoned laver Pyropia yezoensis, processed in various ways. The antioxidative activity of roasted seasoned laver was evaluated at different storage times and the quality of the roasted seasoned laver was improved. The laver was also heated at different temperatures for 3 seconds: $340^{\circ}C$ (SH340), $345^{\circ}C$ (SH345), $350^{\circ}C$ (SH350) and commercial roasted seasoned laver (D) was used as standard. The samples were stored in a transparent acrylic case ($39{\times}27{\times}18cm$) at room temperature for 10 weeks. The total phenolic content began to decrease after 7 weeks of storage and was 395.2, 386.4, 395.8 and $416.4{\mu}g/100g$ for SH340, SH345, SH350 and D, respectively. The respective DPPH (1,1-diphenyl-2-picryl-hydrazyl) radical scavenging activity after 7 weeks of storage were 48.6%, 49.5%, 47.7% and 46.1%. The ferric reducing antioxidant power (FRAP) decreased rapidly after 7 weeks of storage due to the influence of sulfate groups. Therefore, the appropriate storage period and packaging method should be established based on these results.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.336-341
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• 1982

The histochemical examination of Undaria pinnatifida Laver were conducted with light microscope and electron microscope. The results obtained were as follow: 1. Undaria pinnatifida frond were composed with epidermis, cortex and medulla. But the cutting section of Undaria pinnatifida Laver showed that only the epidermal cell were bound to each other. The cortex and medulla of the frond were destroyed during U.P. Laver process. 2. To identification of bind material of U.P. Laver, which were treated with sodium carbonate solution for extraction of alginic acid and reacted with Periodic Acid Schiff(PAS) reagent. And the PAS reaction result was negative by light microscope observation. On this result, we found out that the alginic acid has the binder role of U.P. Laver. 3. Also, the bind structure of U.P. Laver were observed by electron microscope and could well find out the epidermal cell wall and bind position of alginic acid, which were could not observed by light microscope.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.3
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• pp.294-301
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• 2022

Laver Pyropia tenera snack is typically manufactured as an attached laver and carbohydrate-based rice papers or glutinous rice paste. Carbohydrates contribute to a crispy texture and many various additives are used for development of texture. Isomalto-oligosaccharide (IMO) and corn starch (CS) are typical additives in snack products that produce several changes, including texture. We investigated physicochemical properties of laver snacks prepared using IMO/CS ratios of 1:0 (Sample 1), 3:1 (Sample 2), 1:1 (Sample 3), 1:3 (Sample 4), and 0:1 (Sample 5). All of the prepared laver snacks displayed constant drying rates up to 45 minutes. Samples 1 and 5 had higher drying rates than the other laver snacks. Concerning CIE color values, Sample 5 displayed the highest brightness (L^*) value (78.89) and lowest yellowness (b^*) value (6.66). In contrast, Sample 1 displayed the lowest L^* value (74.65) and highest b^* value (17.23). The hardness proportionally decreased along with IMO content. In the sensory evaluation, overall acceptance was highest for Sample 1 with the highest oligosaccharide content.