Total Extractive Nitrogen Research Articles

酵素消化によるカツオ精巣エキス調製の検討

From the point of view of utilization of fish processing waste, the manufacturing method of skipjack spermary extract by autolysis was previously reported. In this experiment, a higher nitrogen extract than that prepared by autolysis was obtained from skipjack spermary by enzymolysis. Each of the enzymes which was prepared from the liver or pyloric caecum of skipjack and purchased from a local store was incubated with minced raw spermary and digested at 37-50°C and pH 2.7-8.0 for 4h. Comparison of total extractive nitrogen and free amino acid composi-tion in the supernatant of the materials and sensory evaluation by the panel revealed that enzyme reaction at 37°C and pH 6.4 for 4h with the crude enzymes from the liver was the most convenient for extract production. This manufacturing method was more efficient in the recovery of nitrogenous extractive compounds than autolysis, as already reported. Three commercial enzymes seemed to contribute to the formation of favorable taste in the extract.

塩蔵さばの塩漬処理および貯蔵中における脂質劣化と自己消化

Oxidation and hydrolysis of lipids and autolysis in salted mackerel Scomber japonicus were investigated. Filleted mackerel which had been salted for 10 days were divided into two groups. One of them was not packaged, the other was packaged with plastic film along with an oxygen absorber, both were stored for 56 days at ambient temperature. During the 10 days of salting, the peroxide value (POV) of lipid of the mackerel increased. However, the oxidized acid content and the fatty acid composition of the lipid did not change during the 10-day salting period. The bulk of polar lipid was hydrolyzed to release free fatty acids during salting. Contents of free amino acids in the muscle increased in varying extents due to autolysis, with some exceptional cases. Histidine and taurine decreased in the contents in the first 7 days of salting. During storage for 56 days, moisture content in the non-packaged salted product decreased from 49% to 39%, while that in the packaged salted one remained unchanged. Lipid oxidation in the non-packaged product proceeded rapidly as judged by POV, oxidized acid content. Highly unsaturated fatty acids of lipid decreased in amount. But the packaged product underwent little lipid oxidation. Total extractive nitrogen and free amino acid contents increased slowly in the non-packaged product, but rapidly in the packaged one. These findings, show that autolysis in the salted mackerel proceeds rapidly during storage at an ambient temperature, but is inhibited markedly when the moisture content of the product decreases to some extent due to drying.

Extractive Components of Scallop and Identification of its Taste-active Components by Omission Test

In order to identify the taste-active components of scallop Patinopecten yessoensis, freeIn order to identify the taste-active components of scallop Patinopecten yessoensis, free and combined amino acids, nucleotides and related compounds, quaternary ammonium bases, organic acids, glycogen, inorganic ions, etc. in the muscle extract were analyzed. High content of glycine and taurine, and a high but somewhat lower content of arginine, alanine and glutamic acid were shown. These five amino acids occupied 97% of the total free amino acids. Besides, considerable amounts of AMP, glycinebetaine, homarine, trigonel- line, trimethylamine oxide and trimethylamine were observed. More than 95% of the total extractive nitrogen was accounted for by these nitrogenous constituents. The succinic acid content was very low, while a large amount of glycogen was detected. As for inorganic ions, Na+, Kt+, Cl- and PO43- were major components. After confirming sensorially that the synthetic extract prepared with pure chemicals in accordance with the analytical data except glycogen and combined amino acids could reproduce the taste of the scallop extract fairly well, we carried out omission tests and found that glycine, glutamic acid, alanine, arginine, AMP, Na+, K+ and Cl- were taste-active.

血合肉のエキス成分組成

Extractive nitrogenous constituents of dark muscles were determined in 13 species of fish having deep-seated dark muscle (skipjack, frigate mackerel), fin dark muscle (blow fish, surgeon fish) and superficial dark muscle (nine other species) and compared them with those of white muscles.The concentration of total extractive nitrogen and creatine were high in the dark muscle as compared with the white muscle. Of the ninhydrin positive substances, taurine concentration was much higher in the dark muscle than in the white muscle, and His, Ala, Lys and Glu were also high in the dark muscle. But His was higher in concentration in the white muscle of pelagic fishes, Except in larval fish, taurine content in the dark muscle of the common mackerel did not vary according to body weight or lipid content. Using chromatography for determining the ninhydrin positive substance in the dark muscle, a few unidentified peaks appeared near the taurine peak. Trimethylamine concentration was higher in dark muscle. But the volatile basic nitrogen concentration was less in the dark than in the white muscle. The total amount of nucleotides and related compounds was less in dark muscle than in white muscle. But the ratio of nucleotides to the total extractive nitrogen was larger in the dark than in the white muscle. Therefore, it was thought that no difference in quantity of nitrogen was found between the two kinds of muscles. However, constitutively, there was large difference in the inosin monophosphate concentration in the dark muscle than the white muscle.

Studies on extractive components of salmonids - IV. Creatine and creatinine in the raw and heated muscles of salmon.

Creatine and creatinine in the 80% ethanol extracts which were the same as employed for the analyses of free amino acids and related compounds in the previous work were estmated. Another muscle extract. 0.25N perchloric acid extract, was also employed to determine the creatine and creatinine contents. In the ethanol extract, the amounts of creatine ranged 22-38 μmol/g in the raw muscles and 29-37 μmol/g in the heated muscles. After heating the muscles, the creatinine content increased more than 10 μmol/g because of dehydration of creatine and the sum of creatine and creatinine also became considerably higher. The increments of total extractive nitrogen after heating reported previously are explainable by the elevation of extractability of creatine. In the perchloric acid extracts, the concentrations of creatine and creatinine in the raw muscles ranged 38-49 and 0.3-0.7 μmol/g respectively, but no consistent differences in the amounts by sex, species, and parts of muscle were noticed. About one third of creatine was converted to creatinine during heating at 100°C for 40min.

Studies on extractive components of salmonids - III. Amino acids and related compounds in the extracts of heated muscles of four species of salmon.

Following the previous work on chum salmon Oncorhynchus keta, the amino acids and related compounds in the 80% ethanol extracts from the heated muscles of four species of Pacific salmon, sockeye salmon O. nerka, chinook salmon O. tshawytscha, coho salmon O. kisutch, and pink salmon O. gorbuscha, were analyzefd from the standpoint of flavor chemistry. Common features such as a very high content of dipeptide anserine, with lower levels of histidine, taurine, alanine, and glycine, were found, in accord with the results for chum salmon. However, a slight but distinct species-specificity was also present, i. e., fairly low levels of histidine in chinook salmon, rather high levels of serine in coho salmon, and somewhat high contents of histidine and markedly low levels of anserine in pink salmon. The amounts of total extractive nitrogen in the heated muscles were remarkably higher than those in the raw muscles in all the samples analyzed.

Studies on flavor components in boiled crabs. II. Nucleotides and organic bases in the extracts.

As a part of strdies on the flavor components of boiled crabs, we have analyzed nucleotides and organic bases in the extracts from the leg meat, hepatopancreas, and ovary of five species of common edible crabs in Japan. AMP and CMP were found to be the major nucleotides in these tissues. Small amounts of GMP, UMP, IMP, and ADP were also detected, along with several kinds of nucleosides and free bases, in some or all samples. The contents of nucleotides in the ovary were three to five times higher than those in the other parts. The leg meat and hepatopancreas were rich in glycine betaine and trimethylamine oxide, with somewhat lower levels of homarine. The ovary accumulated more homarine than the other parts. In most samples, more than 90% of the total extractive nitrogen was accounted for by these constituents and by the amino acids reported in the previous paper.

8種の魚類筋肉エキス中の含窒成分の分布

In order to determine the distribution of nitrogenous constituents in the fish muscle extracts as completely as possible, free and combined amino acids, trimethylamine oxide (TMAO), trimethylamine, creatine, creatinine, and nucleotides were analyzed in 8 species of fish, red sea bream, stone flounder, flathead flounder, flounder, puffer, angler, common mackerel, and jack mackerel.In all species tested, the sum of the nitrogen in these constituents amounted to nearly 90% or more of the total extractive nitrogen. The distribution pattern of nitrogen among these constituents, however, varied considerably from species to species, except for nucleotides which were fairly constant. Free amino acid-N was 7-45% of the total extractive nitrogen, creatine-N 29-58%, and TMAO-N 2-23%.These results are discussed in reference to those reported previously by other authors.

養殖マコンブ発育過程におけるエキスアシノ酸の消長

Among the various cultivating methods of Kombu, one of the palatable seaweeds in Japan, an accelerating method by HASEGAWA was successful in shortening the cultivation period from young to a commercial size corresponding to two-year-old plants. One of the authors reported that although the free proline content was higher in the one-year-old plant than in the two-year-old one, glutamic and aspartic acids were more dominant than the other amino acids in the extractives of the latter, and which has been proved to be superior to the former in quality by organoleptic assessments. The present paper describes the change of the free amino acid composition of Makombu during cultivation by HASEGAWA's accelerated method. Four specimens were collected at Kakkumi near Hakodate City, Hokkaido, in April, May, June and July, and the base, central, and apex of the blade of each specimen was sampled for the analyses of free amino acids, total extractive nitrogen, and thickness. The results obtained are summarized in Table 2 and Figs. 1 to 5. The quantitative changes of glutamic and aspartic acids, proline and alanine were most remarkable. The content of glutamic acid was low in April and May, but it increased considerably in June and July. Proline was richest in the base and central parts in the early growing stage. Thus, the cultivated plant in April and May and that in June and July are similar to the natural ones of the one and two-year-olds, respectively, in free amino acid composition.

リシリコンブの発育程度と主としてエキスアミノ酸組成との関係

Four specimens of Rishiri-kombu, Laminaria ochotensis, differing in growth were collected from Oniwaki in the Rishiri Island, Hokkaido. They were arranged by their degrees of growth as follows: 1) One-year-old plants, 2) one- or two-year-old plants (the plants were not discriminated as to whether they were one- or two-year-olds), 3) two-year-old plants, second grade, and 4) two-year-old plants, first grade. The base and the central parts of the blade were collected separately from each specimen: One half obtained from one side of the blade was used for chemical analyses (amino acid pool, total extractive nitrogen, extractive amino nitrogen, and thickness), and the other half from the other side for the sensory test, The results with the exception of the, sensory test are shown in Table 1. From the table, the following results were drawn: The amounts of glutamic and aspartic acids in one-year-old plants were higher than the two-year-old plants. The ratio of glutamic acid to aspartic acid was about 1:1 in one-year-old plant and one- or two-year-old plant, while it was about 2:1 in the two-year old plants (first and second grade). Proline contents decreased according to the growth of the plant. Cystine was found in one-year-old plants, while it was absent in the two-year-old ones. The presence of tryptophan was quite opposed to the cystine. Two peaks of unknown ninhydrine reactive substances were found on the chromatogram; the one (U2) was between valine and methionine, and the other (U3) between leucine and tyrosine (Fig. 1). The thickness increased with growth.

昆布の品質-IX

Amino acid composition of Makombu extractives was quantitatively determined by using amino acid analyzer. The samples were as follows: raw (I), sun-dried (II-IV), left at room temperature (20°) (VII, VIII), dried at 40° (V), and 80° (VI) of the central part (including the base) of the blade, and raw (IX), and sun-dried (X) of the marginal part (including the apex). No marked differences among the amino acid pools of the extractives from the central part were found, however, a remarkable difference was recognized between the central part and the marginal part. The ratios of ninhydrin reactive nitrogen to total nitrogen of extractives from the central part were approximately 90%, but the values of the latter part were 70%. The recovered amino acid nitrogens were calculated to be as much as 83 to 97% compared to the total extractive nitrogen in the central part. The values of the latter were 57-61%. The main components of the central part were glutamic acid and aspartic acid which occupy about 60 and 30% of the total amino acids, respectively. The contents of proline and alanine followed in lesser amounts. The contents of cysteic acid, D-cystenolic acid, taurine, chondrine, and arginine were very small. Though the content of tryptophan was very small, the presence was recognized in the concentrated extractive. D-cystenolic acid was determined only in the latter part, while an unknown ninhydrin reactive substance which behaves chromatographically like urea, was found only in the central part. The compound proved not to be urea by qualitative tests. Laminin, detected by TAKEMOTO et al.5) in some species of Kombu, was not separately determined from lysine in the present analvses. Four small unknown peaks were present in the neutral and acidic fractions of the extractives of the central part, and two small unknown peaks were found in the same fractions of the latter part.

水産動物肉に関する研究-XXXXIV

As a part of investigation on components of extractives in fish muscle, amino acids, trimethylamine oxide, creatine, creatinine and nucleotides in the dorsal muscle of six species of fishes were determined. Interesting facts on the species-difference in the amount of components were found, as shown in Fig. 1. Muscle of dark-fleshed fishes, such as yellowfin tuna and mackerel, was rich in extractive nitrogen, in which histidine-N was predominant (Table 2). In white-fleshes fishes except flat fish, which was poor in extractive nitrogen, creatine was the dominant component and the amount of histidine was extremely small (Table 3). In elasmobranchs, urea was the major component (Table 2). In the present analyses, 50-80% nitrogen was recovered from total extractive nitrogen.

水産動物肉に関する研究-XXXVIII

In the previous paper, remarkable changes in amount of free arginine and octopine in Sepioteuthis lessoniana FERUSSAC muscle during storage at 5°-7°C, were explained by the rapid conversion of arginine to octopine in the muscle. In order to obtain the detailed pattern of chemical changes occuring in nitrogenous extractives in the muscle during storage, components in extractives were determined including free amino acids, ammonia, trimethylammonium compounds, nucleotides and the related compounds. The results obtained were shown in Figs. 1-4. Chemical changes observed during the first one day were, in addition to the conversion of arginine to octopine previously reported, the degradation of adenosine monophosphate to inosine and hypoxanthine and the formation of ammonia which may be caused by the deamination of adenosine monophosphate. In the period from the first day to the third, no remarkable change was observed in amount of nitrogenous extractives. Thereafter, the degradations of trimethylamine oxide, glycine and proline occured and were followed by the formation of ammonia and trimethylamine. The nitrogenous extractives thus determined constituted 97-99% of the total extractive nitrogen of the muscle, as shown in Fig. 5.

アサクサノリの生化学的研究-I

Porphyra tenera was cultured for a period of 1 to 6 days in the media containing NH4C1, NH4NO3, urea or NaNO3 as the nitrogen source (0.01% as N), and the changes in the amounts of the total nitrogen, extractive nitrogen and extractive amino acids (alanine, aspartic acid and glutamic acid) in the frond were determined. The results are shown in Tables 1 and 2, and are summarized as follows: (1) With NH4-salts as the nitrogen source, the total-N, ext.-N and alanine increased very rapidly, and 20 to 30% of the increment of ext.-N was accounted for by alanine. The increase of aspartic and glutamic acids was not so marked as that of alanine. (2) With urea, the absorption of nitrogen was slow for the first 4 days, turned to be very rapid thereafter, and almost the same amount of nitrogen was absorbed in 6 days as in the case when NH4NO3 was used as the nitrogen source. It is noted, however, that the glutamic acid content increased markedly during the first 2 days. (3) With NaNO3, the total-N content did not increase so rapidly as with NH4-salts, but there was considerable increase in the contents of the three amino acids. (4) It seems that in Porphyra tenera the amount of extractive alanine is more easily affected by the nitrogen condition of the environmental sea water than that of aspartic or glutamic acid.

水産動物肉に関する研究-XVI

In the present paper we have given the account of distribution of extractive nitrogens in muscles of ear-shell, wreath-shell and pond-snail, with special references to their taste. Remarkable differences were found to exist in the amount of amino nitrogen and monoamino nitrogen in muscles of shell-fishes as compared with the those of vertebrate animals. In some shell-fish muscles, especially in ear-shell having the best flavor among the Mollusca, absolute and relative figures for the mono-amino nitrogen were much higher than even in the case of squid muscles which taste is observed being due to the presence of this nitrogen. It is very suggestive, therefore, that the mono-amino acids are the very part of the tasty stuffs in shellfishes. It will be well understood, also, in view of the fact that the amino nitrogen and monoamino nitrogen in most flavorless pond-snail, are absolutely about one-tenth and relatively (as a percentage of total extractive nitrogen) about one-third as much as that of ear-shell. One might expect that autolysed shell-fishes is comparatively poor in flavour, whereas in these figures for autolysed material are somewhat lower than in the fresh one. The general view is that shell-fish muscle are relatively poor in trimethylamine oxide contained flavorous element.