Eight commercial samples of 'nori', or the dried laver Porphyra spp. were extracted with 75% ethanol and the extracts were analyzed for free sugars and organic acids by gas chromatography and for minerals by atomic absorption spectrophotometry. Isofloridoside and floridoside were found to be the predominant free sugars, followed by glucose and galactose. A small amount of mannose, inositol, ribose, arabinose and xylose were also detected. The contents of these sugars were generally lower in nori products of good quality than in those of poor quality. Volatile and nonvolatile organic acids found in the extracts were formic, acetic, propionic, butyric, lactic, oxalic, malonic, fumaric, succinic, malic and citric acids. Among them, formic acid was found to vary greatly from sample to sample. The contents of these organic acids were generally lower in tasty nori samples. Major cations found were Na+ and K+, followed by Mg2+ and Cat+, whereas major anions were Cland PO43-. The nori produced from the indoor cultured laver showed a general pattern similar to nori samples of poor quality, as far as the above components are concerned.

To study of the behavior of Trp-P-1 and its metabolites in rat feces and urine, rats were orally administered with Trp-P-1 (750, 1,500 and 2,500 micrograms/rat), and excreted Trp-P-1 was analyzed using HPLC assay and bacterial mutagenicity assay. The extraction of Trp-P-1 from urine was performed by using the chloroform extraction method, and blue rayon was used for the extraction from feces. When Trp-P-1 was added to rat feces and urine, the recoveries of Trp-P-1 were 85.9 +/- 3.9% and 91.3 +/- 3.7%, respectively. The extracts of feces and urine from rats administered with Trp-P-1 were individually fractionated by thin layer chromatography on C18 gel. The major mutagenic zone corresponding to Trp-P-1 was found at Rf 0.09 in both extracts, while the feces extract gave two additional mutagenic zones at Rf 0.15 and 0.20. More than 97% of the fecal mutagenic activity was due to unchanged Trp-P-1. In rats administered with 750 micrograms of Trp-P-1, the amount of extracted Trp-P-1 and the number of His+ colonies induced by whole excreta were 81.6 +/- 7.1 micrograms (n = 6) and (432 +/- 77) x 10(4) for feces, and 28.7 +/- 4.9 micrograms and (171 +/- 28) x 10(4) for urine. The recoveries of Trp-P-1 in the feces and urine were 10.8 +/- 0.9% and 3.8 +/- 0.7% by HPLC analysis, and 11.1 +/- 2.0% and 4.4 +/- 0.7% by mutagenicity assay respectively. The results of the two assays seemed to show similar patterns of recovery.

This study was carried out to determine the in vitro binding of heterocyclic aromatic amines (HAAs), IQ, MeIQ, Trp-P-1, and Trp-P-2, to low molecular weight cellulose using HPLC assay and bacterial mutagenicity assay. Eight types of low molecular weight cellulose (degree of polymerization (DP): 125-180, particle size: 8-80μm, settling volume in water (SV): 3.2-6.6mL/g) were used in this study. All types of DP 180 cellulose showed higher adsorptive capacity for IQ, MeIQ, Trp-P-1 and Trp-P-2 than the DP 125 and DP 130.The 4 HAAs showed no significant difference in adsorption by cellulose from 10 to 80μm in particle size. In the case of 2 types of cellulose with the same DP (180) and particle size (40μm) but different SV (5.4mL/g, 4.0mL/g), Trp-P-1, Trp-P-2 and MeIQ showed no difference in adsorption but IQ was adsorbed at a higher rate (1.3 times) by the cellulose of larger SV. Highly hydrophobic compounds among the 4 HAAs (Trp-P-1 and Trp-P-2) were adsorbed by cellulose in large quantities, strongly and quickly. The results of the two assays seemed to show similar patterns in the adsorption of the 4 HAAs by the 8 types of cellulose. Based on the HPLC assay, Trp-P-1 and Trp-P-2 were adsorbed by the 8 types of cellulose at rates of 81-95%and 71-95%. Similarly, the numbers of revertants per plate induced by Trp-P-1 and Trp-P-2 treated with these celluloses were 0.7-2.1% and 0.4-5.0% of the control, respectively. From these results, it has been clarified that low molecular weight cellulose with a DP about 24 to 80 times smaller than the native value can adsorb HAAs.

Adsorption of IQ, Trp-P-1 and Trp-P-2 on insoluble dietary fiber, cellulose, CM-cellulose, xylan, chitin, collagen and acid detergent fiber (ADF: containing cellulose and lignin) from nine species of edible plants was measured by HPLC. Cellulose and ADF from burdock, dropwort and bamboo shoot showed high adsorptive power for IQ, Trp-P-1 and Trp-P-2. The results suggest that consumption of edible plants containing cellulose would help to prevent the internal absorption of heterocyclic amines formed in cooked fish and meats.

The isozyme profiles of Porphyra were examined by means of polyacrylamide gel electrophoresis to establish a method for distinguishing Porphyra species. The conchocelis of Porphyra used in this experiment included P. tenera (Minomi), P. tenera (Matsukawa), P.yezoensis f.narawaensis, P.yezoensis (Saga10), P.yezoensis (Green), and P.seriata (Shimabara). Among the detected enzymes, the electrophoretic profiles of GOT, GDH, PGM, G6PD, ADH, and AK isozymes varied. In particular, the GOT profile distinguished P. tenera, P.yezoensis, and P.seriata, which was the wild type, whereas the AK profile differed in all six species. In addition, the GDH, PGM and ADH profiles distinguished all six species, when combined with those of GOT.In conclusion, the GOT, AK, GDH, PGM and ADH profiles obtained by polyacrylamide gel electrophoresis using conchocelis are thought to be useful for identifying of Porphyra species.

Eight commercial samples of ‘nori’, or the dried laver porphyra spp. were extracted with 75% ethanol and the extracts were analyzed for free sugars and organic acids by gas chromatography and for minerals by atomic absorption spectrophotometry. Isofloridoside and folridoside were found to be the predominant free sugars, followed by glucose and galactose. A small amount of mannose, inositol, ribose, arabinose and xylose were also detected. The contents of these sugars were generally lower in nori products of good quality than in those of poor quality. Volatile and nonvolatile organic acids found in the extracts were formic, acetic, propionic, butyric, lactic, oxalic, malonic, fumaric, succinic, malic and citric acids, Among them, formic acid was found to vary greatly from sample to sample. The contents of these organic acids were generally lower in tasty nori samples. Major cations found were Na+ and K+, followed by Mg2+ and Ca2+, whereas major anions were Cl- and PO43- The nori produced from the indoor cultured laver showed a general pattern similar to nori samples of poor quality, as far as the above components are concerned.