Structural Characterization of Natural Polyisoprenes: Solve the Mystery of Natural Rubber Based on Structural Study

2001 ◽  
Vol 74 (3) ◽  
pp. 355-375 ◽  
Author(s):  
Yasuyuki Tanaka
Keyword(s):  
Fatty Acids ◽  
Natural Rubber ◽  
Structural Characterization ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Terminal Group ◽  
Radical Scavenger ◽  
Branch Points

Abstract Structural characterization of naturally occurring polyisoprenes was carried out to solve the mystery of natural rubber (NR), such as the biosynthesis mechanism of rubber formation, the origin of outstanding properties of NR and the role of rubber in rubber trees. The NMR analysis, based on terpenes and polyprenols as models, disclosed the structure of both terminal groups of rubber chain. Structural evidence indicated that the biosynthesis of rubbers from Lactarius mushroom and leaves of high plants starts from trans, trans-farnesyl diphosphate or trans, trans, trans-geranylgeranyl diphosphate and terminates by dephosphorylation to form a hydroxyl terminal group. The biosynthesis of NR was presumed to start from unidentified initiating species containing two trans-isoprene units and peptide group and to terminate forming a phospholipid terminal group. The initiating group of NR associated with proteins formed branch points, which can be decomposed by enzymatic deproteinization. The branch points formed by phospholipid group were decomposed by transesterification with sodium methoxide. Rapid crystallization of NR was explained by the presence of mixed fatty acids synergistically with linked fatty acids, which were included in phospholipid. Saturated fatty acids linked to rubber chain induced crystallization, while mixed unsaturated fatty acids acted as plasticizer and accelerated the crystallization rate. This was confirmed by the preparation of model cis-polyisoprene grafted with stearic acid. The green strength of NR decreased to the same level as synthetic cis-polyisoprene after transesterification, indicating the effect of branching formed by the phospholipid terminal group and fatty acids in NR. The role of NR in Hevea trees was analyzed using NR from Hevea trees never tapped before. The formation of hard gel and oxidative degradation during the storage of NR in Hevea trees suggested that NR acted as a radical scavenger to remove hydroperoxide.

Structural Characterization of α-Terminal Group of Natural Rubber. 2. Decomposition of Branch-Points by Phospholipase and Chemical Treatments

2005 ◽  
Vol 6 (4) ◽  
pp. 1858-1863 ◽  
Author(s):  
Lucksanaporn Tarachiwin ◽  
Jitladda Sakdapipanich ◽  
Koichi Ute ◽  
Tatsuki Kitayama ◽  
Yasuyuki Tanaka
Keyword(s):  
Natural Rubber ◽  
Structural Characterization ◽  
Terminal Group ◽  
Branch Points ◽  
Chemical Treatments

Composition of Color Substances of Hevea Brasiliensis Natural Rubber

2007 ◽  
Vol 80 (2) ◽  
pp. 212-230 ◽  
Author(s):  
Jitladda Sakdapipanich ◽  
Kittipong Insom ◽  
Nataphon Phupewkeaw
Keyword(s):  
Fatty Acids ◽  
High Resolution ◽  
Natural Rubber ◽  
Structural Characterization ◽  
Unsaturated Fatty Acids ◽  
Rubber Latex ◽  
Naturally Occurring ◽  
Bottom Fraction ◽  
Light Color

Abstract It is accepted that NR gives naturally occurring color, which restrict many applications such as light-color products. Therefore, characterization of color substances presenting in NR is very useful to develop the certain methodology to eliminate them completely or partly from NR in the future. In this work, an attempt was made to purify and characterize the color substances extracted from various fractions of Hevea rubber latex by certain methods, using high-resolution structural characterization techniques. It was found that the content of color substances extracted from fresh latex (FL), rubber cream, bottom fraction (BF), Frey Wyssling (FW) particles and STR 20 were different. Based on the high-resolution spectroscopic analyzes, it was found that the color substances extracted from NR were composed of carotenoids, tocotrienol esters, fatty alcohol esters, tocotrienols, unsaturated fatty acids, fatty alcohols, diglyceride and monoglyceride. The results will be useful for rubber-technologist to identify the origin to make obnoxious color in natural rubber, especially in some applications which are restricted by such the color.

Structural Characterization of α-Terminal Group of Natural Rubber. 1. Decomposition of Branch-Points by Lipase and Phosphatase Treatments

2005 ◽  
Vol 6 (4) ◽  
pp. 1851-1857 ◽  
Author(s):  
Lucksanaporn Tarachiwin ◽  
Jitladda Sakdapipanich ◽  
Koichi Ute ◽  
Tatsuki Kitayama ◽  
Takashi Bamba ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Structural Characterization ◽  
Terminal Group ◽  
Branch Points

scholarly journals Identification and Characterization of Oleaginous Yeast Isolated from Kefir and Its Ability to Accumulate Intracellular Fats in Deproteinated Potato Wastewater with Different Carbon Sources

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Iwona Gientka ◽  
Marek Kieliszek ◽  
Karolina Jermacz ◽  
Stanisław Błażejak
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fossil Fuels ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Carbon Sources ◽  
Debaryomyces Hansenii ◽  
Industry Waste ◽  
Identification And Characterization

The search for efficient oleaginous microorganisms, which can be an alternative to fossil fuels and biofuels obtained from oilseed crops, has been going on for many years. The suitability of microorganisms in this regard is determined by their ability to biosynthesize lipids with preferred fatty acid profile along with the concurrent utilization of energy-rich industrial waste. In this study, we isolated, characterized, and identified kefir yeast strains using molecular biology techniques. The yeast isolates identified wereCandida inconspicua,Debaryomyces hansenii,Kluyveromyces marxianus,Kazachstania unispora, andZygotorulaspora florentina. We showed that deproteinated potato wastewater, a starch processing industry waste, supplemented with various carbon sources, including lactose and glycerol, is a suitable medium for the growth of yeast, which allows an accumulation of over 20% of lipid substances in its cells. Fatty acid composition primarily depended on the yeast strain and the carbon source used, and, based on our results, most of the strains met the criteria required for the production of biodiesel. In particular, this concerns a significant share of saturated fatty acids, such as C16:0 and C18:0, and unsaturated fatty acids, such as C18:1 and C18:2. The highest efficiency in lipid biosynthesis exceeded 6.3 g L−1.Kazachstania unisporawas able to accumulate the high amount of palmitoleic acid.

Characterization of Biodiesel from Vegetable Oil Using Comprehensive Two-Dimensional Gas Chromatography

2012 ◽  
Vol 260-261 ◽  
pp. 312-317 ◽  
Author(s):  
Ferdinando Corriere ◽  
Giorgia Peri ◽  
Vincenzo La Rocca
Keyword(s):  
Fatty Acids ◽  
Gas Chromatography ◽  
Internal Combustion Engines ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Combustion Engines ◽  
Two Dimensional ◽  
Mass Percentage ◽  
Heating Value

Biodiesel from vegetable oils has been analyzed and its suitability for internal combustion engines has been assessed. The Standard biofuel’s characteristics have been investigated. Gas chromatography (GC) tests were carried out to characterize the fatty acid behavior. It was found that the mass percentage of saturated fatty acids did not change substantially with time, while unsaturated fatty acids increased with time for both B100 and B30. An increase in density for B100 and B30 with time was noted. Biodiesel density was within the standardization. The calorific values of biodiesel and its blend increased with time. Higher heating value for B100 increased from 41 to 43 MJ/kg while B30 increased from 44 to 45 MJ/kg.

Lipids and their seasonal variation in the nucellar layers of Scots pine (Pinus sylvestris) seeds

1996 ◽  
Vol 74 (9) ◽  
pp. 1416-1424 ◽  
Author(s):  
Eila Tillman-Sutela ◽  
Anu Johansson ◽  
Pälvi Laakso ◽  
Heikki Kallio ◽  
Anneli Kauppi
Keyword(s):  
Fatty Acids ◽  
Seasonal Variation ◽  
Fatty Acid ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Lipid Fraction ◽  
Single Fatty Acid

The content, composition, and seasonal variation of lipids in the nucellar layers of two mature Scots pine seed lots from northern and central Finland were studied. These lipophilic layers, which are located inside the seed coat, are composed of collapsed cells and restrict the imbibition of seeds. In this study, epicuticular wax was found on their surface; in particular, the surface of the nucellar cap was composed of intermeshing wax rods. The content of total lipids of the nucellar layers varied seasonally from 10 to 24%, being highest in April. In addition to simple lipids, which formed the most abundant lipid fraction in nucellar layers, small amounts of phospho- and glyco-lipids were also present. The proportion of simple lipids and their fatty acid composition in the seeds of both provenances remained constant throughout the year, whereas seasonal variation was found in the proportions of phospho- and giyco-lipids and in their fatty acids. In general, the variation was more marked in the northern seed lot. The unsaturated fatty acids dominated in the fractions of simple lipids and phospholipids, with linoleic acid being the most abundant single fatty acid. The saturated fatty acids with more than 22 carbon atoms were most abundant in the glycolipid fractions. The role of lipids for the function of the collapsed nucellar layers in the regulation of imbibition and germination of pine seeds is discussed. Keywords: Pinus sylvestris L., northern seeds, fatty acids, imbibition, germination.

Characterization of Whey Cheese Packaged under Vacuum

2000 ◽  
Vol 63 (2) ◽  
pp. 216-221 ◽  
Author(s):  
MANUELA E. PINTADO ◽  
F. XAVIER MALCATA
Keyword(s):  
Fatty Acids ◽  
Thermal Processing ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Fatty Acid Content ◽  
Vacuum Packaging ◽  
Concomitant Increase ◽  
Wide Range ◽  
Microbial Groups

Vacuum packaging was assayed at 4°C and was tested in comparison to unpackaged counterparts, in both microbiological and physicochemical terms, in studies pertaining to the preservation of Requeijão, a traditional Portuguese whey cheese. Bacteria were absent (i.e., <10 CFU/g) in whey cheeses on the day of manufacture as a result of thermal processing. After storage, both unpackaged and packaged cheeses exhibited high viable counts of Bacillus, Pseudomonas, Enterobacteriaceae, and lactic acid bacteria (especially lactococci). Yeasts, staphylococci, enterococci, and spore-forming clostridia were severely inhibited by the package vacuum combined with the increasing acidification developed therein. Whey cheeses packaged under vacuum underwent substantial acidification, slight depletion of lactose, and no significant variation in moisture content or texture; conversely, unpackaged whey cheeses exhibited substantial loss of water and a concomitant increase in rigidity. Vacuum packaging strongly inhibited lipolysis (even if viable counts of some microbial groups were high); saturated fatty acids (mainly C16:0 and C14:0) accounted for ca. 73% of the total free–fatty acid content, whereas the most concentrated unsaturated fatty acids were C18:1 and C18:2 (ca. 14% each). The conclusions generated in our study are, in general, useful for a wide range of whey cheeses worldwide: i.e., Requéson (Spain), Ricotta (Italy), Broccio (France), and Anthotyro (Greece). In addition, our conclusions are particularly helpful in terms of improving the safety of Requeijão, a widely acclaimed dairy specialty.

Mixed monolayers of simple saturated and unsaturated fatty acids

1977 ◽  
Vol 30 (3) ◽  
pp. 511 ◽  
Author(s):  
AI Feher ◽  
FD Collins ◽  
TW Healy
Keyword(s):  
Fatty Acids ◽  
Mole Fraction ◽  
Saturated Acid ◽  
Unsaturated Fatty Acids ◽  
Hydrophobic Interactions ◽  
Saturated Fatty Acids ◽  
Mixed Monolayers ◽  
Mixed Films ◽  
Pressure Area

The conventional surface pressure-area per molecule isotherms of single and binary films in the acid series, (Z)-octadec-9-enoic (?oleic?), its (E) isomer (?elaidic?), octadecanoic (?stearic?) and eicosanoic (?arachidic?), have been obtained up to and including collapse. While the films formed from binary mixtures of saturated fatty acids were ideal at all mole fractions, the binary films formed with a saturated acid and the (E) isomer of octadec-9-enoic acid produced negative deviations from ideality; films of a saturated acid and the (Z) isomer produced positive deviations from ideality. Mixed films of the two unsaturated acids showed negative deviations at low mole fraction of (Z) isomer and positive deviations at low mole fraction of the (E) isomer. The role of chain stereochemistry and the effect of (Z) and (E) double bonds on hydrophobic interactions in mixed monolayers is considered.

scholarly journals CHEMICAL AND NUTRITIONAL CHARACTERIZATION OF PERILLA FRUTESCENS SEED OIL

2012 ◽  
Vol 1 ◽  
Author(s):  
Mohammad Asif ◽  
Guru Ram Das
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Seed Oil ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Perilla Frutescens ◽  
Plant Oils ◽  
Medicinal Uses ◽  
And Control

Perilla frutescens seeds contain saturated fatty acids and unsaturated fatty acids which include the monounsaturated and polyunsaturated fatty acids. These seeds contain approximately 35-40% oil. The oil of Perilla frutescens contains ω-3 fatty acids (54-64%), ω-6 fatty acids (≈14%) and the ω-9 fatty acids (small amount). In comparing to other plant oils, Perilla oil contains one of the highest proportions of ω-3 fatty acids. These polyunsaturated fatty acids are the most beneficial to human health in prevention and control of various diseases like cardiovascular disorders, cancer, inflammation, rheumatoid arthritis etc. This review article describes briefly the benefits and the medicinal uses of Perilla frutescens seeds.

Characterization of fatty acids linked to natural rubber—role of linked fatty acids on crystallization of the rubber

Polymer ◽  
2000 ◽  
Vol 41 (20) ◽  
pp. 7483-7488 ◽  
Author(s):  
S Kawahara ◽  
T Kakubo ◽  
J.T Sakdapipanich ◽  
Y Isono ◽  
Y Tanaka
Keyword(s):  
Fatty Acids ◽  
Natural Rubber
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