Correlation between skeletal muscle fiber type and free amino acid levels in Japanese Black steers

Free amino acids are important components of tastants and flavor precursors in meat. To clarify the correlation between muscle fiber type and free amino acids, we determined the concentrations of various free amino acids and dipeptides in samples of different muscle tissues (n = 21), collected from 26‐month‐old Japanese Black steers (n = 3) at 2 days postmortem. The proportions of the myosin heavy chain (MyHC), slow (MyHC1) and fast (MyHC2) isoforms were determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). The contents of free amino acids and dipeptides were measured by high performance liquid chromatography (HPLC). The MyHC isoform composition varied among the tissue samples. The MyHC1 proportion ranged from 6.9% ± 3.9% to 83.3% ± 16.7%. We confirmed that there was a strong positive correlation between MyHC1 composition and total free amino acid concentrations, including those for two dipeptides. Among the 31 measured free amino acids and dipeptides, 11 showed significant positive correlations and five showed significant negative correlations with MyHC1 composition. These results suggest that a high MyHC1 content induces high free amino acid contents in bovine muscles possibly because of greater oxidative metabolism. This high level of free amino acids could contribute to the intense flavor of meat that is rich in slow‐twitch fibers.     

Flower and seed production in a series of flowerings from sporadic events before to after mass flowering of the dwarf bamboo Sasa veitchii var. hirsuta

The aim of this study was to determine seed production patterns in a series of flowerings from sporadic events before to after mass flowering and to clarify the relationship between the occurrence of second flowering and seed production in the first flowering of mass-flowering events for S. veitchii var. hirsuta. The results revealed that ratios of numbers of seeds to florets per inflorescence in the first and second flowerings of a mass-flowering event were as large as those in the first flowering of a sporadic-flowering event before mass flowering, and were larger than those in the second flowering of a sporadic-flowering event before mass flowering and in both flowerings of a sporadic-flowering event after mass flowering. However, estimated number of produced seeds per square meter in mass flowering was higher than that in sporadic flowering before it. This suggests that seed production is promoted in mass flowering, and that sporadic flowering beforehand can potentially contribute to successful regeneration. At a site where seeds were produced in the first flowering of a mass-flowering event, flower production and the seed germination ratio were smaller in the second flowering. Conversely, at a site where few seeds were produced in the first flowering of a mass-flowering event, there was no significant difference in flower production between the first and second flowerings, and the seed germination ratio in the second flowering was more than 40 %. This suggests that the second flowering of a mass-flowering event is related to seed production in the first flowering.     

Investigation on the Stabilization of the Humus in Mollisols

Soil organic matter in Mollisols is often preserved for an extremely long period (e.g. > 3000 years). We confirmed that the stable organic matter in Mollisols is the medium to coarse sized (0.2–2.0 μm) clay-humus complex with humic acid combined with calcium as the main organic constituent. The argillic horizon contained relatively large amounts of clay-humus complexes and had relatively high carbon contents, humic acid/fulvic acid ratios and degrees of humification of humic acid. Medium clay and coarse clay fractions preserved the organic carbon most efficiently. Highly humified humic acid could be detected even in the uppermost part of the Ah horizon and was probably stabilized in lower horizons by forming a complex with clay fractions.     

Use of High Oleic Corn in Catfish Feeds

High oleic corn is a genetic variant that contains more protein, lipid, and oleic acid and less linoleic acid than regular corn. A study was conducted to compare weight gain and feed conversion of year-1 and year-3 channel catfish Ietalurus punctatus , and processing yield, body composition and frozen storage stability of year-3 channel catfish fed high oleic corn and number 2 yellow (regular) corn in extruded production diets. A commercial-type diet formulated to contain 30% protein and made with regular corn served as a control. A second diet contained high oleic corn in place of regular corn on an equal (air-dry) weight basis. A third diet contained high oleic corn in substitution for regular corn and part of the soybean meal to limit protein content to 28%, which was equal to that of the control diet. The experimental diets were fed to year-1 channel catfish (average initial weight 5.1 g) in aquaria for 10 wk and to year-3 channel catfish (average initial weight 1.07 kg) in 0.04–ha ponds for 14 wk. Substitution of high oleic corn for regular corn on an equal (air-dry) weight basis provided significant gain ( P < 0.01) of year-1 channel catfish but not of year-3 fish. Use of high oleic corn diets designed to be equal in protein content did not affect weight gain of either group of fish. Replacement of regular corn with high oleic corn caused a significant ( P < 0.01) reduction in linoleic acid but no significant ( P > 0.20) increase in oleic acid in the flesh of fish. Proximate body composition, dressing yield, fillet yield, visceral fat, and liver weight were not significantly different among treatments. Sensory scores of fillets frozen for 3 and 6 mo were not significantly different among treatments. Peroxide value, thiobarbituric acid number and free fatty acids increased with frozen storage time but were not different among treatments.     

Behavior of phenolic substances in the decaying process of plants: I. Identification and Quantitative Determination of Phenolic Acids in Rice Straw and Its Decayed Product by Gas Chromatography

Phenolic acids in rice straw and its decayed product were surveyed and quantitatively analyzed by gas chromatography.

1) Thirteen kinds of phenolic acids in rice straw and its decayed product were identified. Besides p-hydroxybenzoic, vanillic, P-coumaric, and ferulic acids which had been already reported, nine phenolic acids were newly identified; these were benzoic, salicylic, syringic, protocatechuic, β-resorcylic, caffeic, sinapic, gallic, and gentisic acids.

2) A gas chromatographic analysis was applied to the micro-determination of major phenolic acids in rice straw and . the decayed products. The methanolic alkaline extracts from them were washed with ether, acidified, transferred into ether, trimethylsilylated, and injected into a gas chromatograph equipped with a silicon SE-30 column. The recoveries of p-coumaric, p-hydroxybenzoic, vanillic, and syringic acids were more than 90%, and ferulic and syringic acids were recovered at about 70%.

3) The content of each of the above described major phenolic acids in rice straw ranged from 0.002 to 0.037% per dry weight. p-Coumaric acid was contained in the largest amount. Ferulic and vanillic acids followed. In the decayed straw, these contents decreased to 0.002–0.017%. The whole phenolic substances in ether-extracted fraction were present at 0.34%, and the amount decreased to one-third during the decaying process.     

Degradation of PCP in soils

In laboratory experiments, the degradation of PCP in soil with regard to the relationship to soil properties was studied under upland and flooded conditions using gas-chromatographic techniques. The degradation products and their behavior were elucidated by using 10 diCferent soils collected from rice fields and adjacent upland fields and one sample of a subsoil from the forest. The results are as follows:

1) The degradation of PCP in soils was faster under flooded conditions than upland conditions.

2) The degradation under flooded conditiont was more rapid in soils collected from rice fields than in those from adjacent upland fields, Tbe reverse was true under upland conditions.

3) The degradation rate was highly correlated with the organic matter content of the soil. Almost 100% of the PCP remained in the subsoil sample even after 50 days of incubation. The rate was slightly correlated with the clay mineral composition, free iron content, phosphate absorption coefficient and C.E.C., but hardly at all with texture, clay content, degree of base saturation, soil pH and available phosphorus content.

4) As the degradation products of PCP, 3 tetrachlorophenols, 4 or 5 trichlorophenols and PCP methyl ether were detected, PCP methyl elher and 2, 3, 4, 5-tetrachlorophenol were the major products, but the amount of the latter varied greatly during the course of incubation.     

Chemical studies on soil humic acids

Abstract

Relationships between elementary compositions and types of humic acids or the "degrees of humification were studied statistically using 39 humic acids prepared from various types of soils. Mean values of C%. H%. N%, 0%, H/C, N/C, and O/C of the different types of humic acids (A. B. Rp(l), Rp(2). and Po) were compared. The elementary compositions of various types of humic acids were proven by variance analyses to be significantly distinct. Linear regression analyses of C%, H%, N%. 0%, H/C, N/C, or O/C on RF or AlogK values were also carried out on 35 humic acids excluding the P_+~+++ type humic acids. The linear associations were found to be significant between C%-RF (5% level), H%-RF, H%-?logK, H/C-RF and HIC-?logK (0.1% level), N/C-RF(O.1% level). N%-RF(l% level), N%-?logK N/C-?logK(5% level), and ?logK (1% level), while no significant relationship was found with regard to C%;-?logK, 0%-?logK (both 5% level) and O/C-RF and O/C-?logK (l0% level). Carbon and oxygen contents of humic acids may be apt to reflect the different conditions of soils. The deeper the visible light absorption of humic acids and so the higher the degrees of humification, the lower the hydrogen contents of humic acids were. Though nitrogen content showed a trend similar to the trend of hydrogen content against RF values as a whole. the nitrogen content of less humified humic acids (Rp type) varied from very low to very high values. suggesting the enrichment of nitrogen into humic acid molecules in the early stage of humification. In the H/C versus O/C diagram, humic acids occupied an area reserved for the oxydation products of lignins. The area was fairly wide and “J”-shaped, that is, in the early to the middle stage of humification humic acids were arranged in the direction of dehydrogenation or demethanation, and in the later stage they were arranged in the direction of dehydration.     

Comparison of connective tissue structure and muscle toughness of spotted mackerel <Emphasis Type="Italic">Scomber australasicus</Emphasis> and Pacific mackerel <Emphasis Type="Italic">S. japonicus</Emphasis> during chilled and frozen storage

To characterize post-mortem changes in fish meat quality during chilled and frozen storage, muscle toughness and the connective tissue structure of muscle were compared between two mackerel species, spotted mackerel Scomber australasicus and Pacific mackerel S. japonicus. Measurement of the breaking strength of meat slices from both non-frozen fresh fish and frozen-thawed fish revealed that spotted mackerel meat was softer than Pacific mackerel meat. Under scanning electron microscopic observation, the connective tissue of non-frozen meat of spotted mackerel was thinner than that of Pacific mackerel. In addition, the collagen content in the spotted mackerel meat was lower than that of Pacific mackerel. These findings suggest that connective tissue structure might influence muscle toughness in mackerel.