The Absorption Spectrum of Chlorophyll a Crystals

1954 ◽  
Vol 22 (1) ◽  
pp. 142-142
Author(s):  
Earl E. Jacobs ◽  
A. Stanley Holt
Keyword(s):  
Absorption Spectrum ◽  
Chlorophyll A

scholarly journals AKTIVITAS TERMOPROTEKSI DAN FOTOPROTEKSI EKSTRAK KASAR KAROTENOID MESOKARP KELAPA SAWIT (Elaeis guineensis Jacq.) TERHADAP KESTABILAN KLOROFIL-A)

2019 ◽  
Vol 12 (1) ◽  
pp. 112-123
Author(s):  
Dece Elisabeth Sahertian ◽  
Indriatmoko Indriatmoko ◽  
Leenawaty Limantara ◽  
Tatas Hardo Panintingjati Brotosudarmo
Keyword(s):  
Absorption Spectrum ◽  
Light Intensity ◽  
Chlorophyll A ◽  
Elaeis Guineensis ◽  
Heating Time ◽  
Protective Function ◽  
Stability And Instability ◽  
In Series ◽  
Elaeis Guineensis Jacq ◽  
The Stability

AbstrakKelapa sawit (Elaeis guineensis Jacq.) merupakan tanaman yang mengandung karotenoid tinggi pada mesokarp yang merupakan bagian dari buah. Cahaya dan suhu dalam proses fotosintesis memberi pengaruh bagi kestabilan dan ketidakstabilan karotenoid dan klorofil. Penelitian ini bertujuan untuk mengetahui aktivitas fotostabilitas dan termostabilitas ekstrak karotenoid mesokarp terhadap klorofil-a yang diiradiasi dengan lampu volpi (intralux 4100) daylight pada intensitas cahaya 31960 lux, 47040 lux dan 76640 lux dalam seri waktu penyinaran 0, 5, 10, 15, 20, 25, dan 30 menit serta dipanaskan pada suhu 25, 50, 65, dan 90 °C dengan seri waktu pemanasan 0, 1, 2, 3, 6, 9, dan 24 jam. Pengukuran spektrum serapan tiap perlakuan diukur menggunakan Spektrofotometer UV-Tampak pada panjang gelombang 300–800 nm. Hasil penelitian menunjukkan bahwa karotenoid tidak melakukan fungsi proteksi dengan baik pada perlakuan pemanasan 65 °C dan 90 °C selama 24 jam, serta perlakuan iradiasi hingga 30 menit pada ketiga intensitas cahaya. Kesimpulan dari penelitian ini adalah klorofil-a murni lebih stabil pada perlakuan pemanasan dan iradiasi. Kemampuan proteksi karotenoid terhadap kestabilan klorofil-a yaitu pada suhu di bawah 50 °C dan pada intensitas cahaya di bawah 31960 lux.Abstract Oil palm (Elaeis guineensis Jacq.) is a plant that contains high carotenoids in its mesocarp which is part of the fruit. Light and temperature in photosynthesis may affect the stability and instability of carotenoid and chlorophyll. The aim of this research was to examine the thermostability and photostability activities of the carotenoids in mesocarp extract on chlorophyll which were irradiated by Volpi lamp (4100 intralux) daylight at light intensity of 31960 lux, 47040 lux and 76640 lux in series of time radiation 0, 5, 10, 15, 20, 25, and 30 minutes and heated at 25, 50, 65, and 90°C with series of heating time 0, 1, 2, 3, 6, 9, and 24 hours. Measurement of the absorption spectrum of each treatment was measured using a UV-Vis Spectrophotometer at a wavelength range of 300–800 nm. The results showed the protective function of carotenoids did not perform well at the heating treatments of 65°C and 90°C in 24 hours and at the irradiation for 30 minutes in all the light intensities. In conclusion, pure chlorophyll-a is more stable in heating and irradiation treatments. Carotenoid protection ability against chlorophyll-a is at temperatures below 50 °C and at a light intensity below 31960 lux.

The absorption spectrum of chlorophyll a and the chlorophyll/dioxane and chlorophyll/benzoquinone interactions

1974 ◽  
Vol 26 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Joseph Le Brech ◽  
Roger M. Leblanc ◽  
Adel F. Antippa
Keyword(s):  
Absorption Spectrum ◽  
Chlorophyll A

A PROPOSED STRUCTURE FOR CHLOROPHYLL d

1959 ◽  
Vol 37 (3) ◽  
pp. 507-514 ◽  
Author(s):  
A. S. Holt ◽  
H. V. Morley
Keyword(s):  
Absorption Spectrum ◽  
Chlorophyll A ◽  
Potassium Permanganate ◽  
Oxidation Product ◽  
Visible Absorption Spectrum ◽  
Visible Absorption ◽  
Chlorophyll D ◽  
Vinyl Group

Treatment of chlorophyll a or methyl chlorophyllide a with potassium permanganate effected oxidation of the 2-vinyl group without concomitant oxidation of the cyclopentanone ring. One of the products obtained was of especial interest because its visible absorption spectrum was identical with that of a previously known, but chemically uncharacterized, pigment—chlorophyll d. The preparation and identification of this oxidation product as 2-desvinyl-2-formyl-chlorophyll-a is given and its probable identity with chlorophyll d is discussed in detail.

III. Contributions to the chemistry of chlorophyll. Part I

1885 ◽  
Vol 38 (235-238) ◽  
pp. 336-340 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Chlorophyll A ◽  
Simple Modification

The paper treats of the products formed by the action of acids on chlorophyll. A ll who have worked with chlorophyll are familiar with the peculiar effects produced in solutions of chlorophyll by the action of acids. The colour is changed, and an absorption spectrum makes its appearance which differs from that of chlorophyll. According to some, these changes are due to a simple modification of the chlorophyll, others consider they are caused by the formation of products of decomposition. The latter view seems the more probable.

Spectroscopic and Thermodynamic Studies of Chlorophyll Containing Monolayers and Vesicles

1979 ◽  
Vol 34 (5-6) ◽  
pp. 406-413 ◽  
Author(s):  
J. Luisetti ◽  
H. Möhwald ◽  
H. J. Galla
Keyword(s):  
Phase Transition ◽  
Absorption Spectrum ◽  
Lipid Bilayer ◽  
Chlorophyll A ◽  
Solubility Limit ◽  
Molar Ratio ◽  
Lipid Phase ◽  
Lipid Phase Transition ◽  
Fluorescence Measurements ◽  
Lipid Bilayer Vesicles

Abstract Absorption and fluorescence experiments on pheophytin and chlorophyll containing lipid bilayer vesicles are reported. Pheophytin aggregates on the vesicles are established from an additional red shifted band (at 695 nm) in the absorption spectrum. These aggregates contain pheophytin in an arrangement with the molecular planes of the porphyrin rings being parallel and cover about 10% of the vesicle surface. The lipid phase dissolves pheophytin up to a molar ratio of 15% above the lipid phase transition. This solubility limit decreases hardly on solidification of the lipid.For chlorophyll a containing vesicles the aggregates are not observed in the absorption spectrum. The chlorophyll solubility is about equal to that of pheophytin. This suggests that the phase separa­ tion indicated from fluorescence measurements at temperatures below the lipid phase transition does not lead to the formation of strongly bound chlorophyll aggregates.

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