Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Blue Bananas

20.10.2008
Ripening bananas glow an intense blue under black light

Ripe bananas are of course yellow. However, under black light, the yellow bananas are bright blue, as discovered by scientists at the University of Innsbruck (Austria) and Columbia University (New York, USA). The team, headed by Bernhard Kräutler, reports in the journal Angewandte Chemie that the blue glow is connected to the degradation of chlorophyll that occurs during ripening. In this process, colorless but fluorescing breakdown products of chlorophyll are concentrated in the banana peel.

The usual appearance of bananas is mainly the result of carotenoids. Under normal light, these natural pigments appear yellow. Under UV light, known to partygoers as black light, ripening bananas appear blue instead. There is no difference between naturally ripened bananas and those ripened with the use of ethylene gas. Green, unripe bananas do not fluoresce. The intensity of the luminescence correlates with the breakdown of the green pigment chlorophyll. As the ripening continues to progress, the blue glow decreases. “Surprisingly, this blue luminescence apparently has been entirely overlooked,” says Kräutler.

By means of various spectroscopic techniques, the team analyzed the structure of the main breakdown products. In doing this, they identified a propionate ester group, a modification never seen before in a chlorophyll breakdown product. This group has a stabilizing effect and could explain the unusually long duration of the fluorescing intermediates in bananas. Fluorescing chlorophyll catabolytes have otherwise only been found as short-lived intermediate products in higher plants.

Why does the breakdown of chlorophyll occur differently in bananas than in other higher plants, including even banana leaves? Kräutler suggests two different explanations: “In contrast to humans, many of the animals that eat bananas can see light in the UV range. The blue luminescence of the banana fruit could give them a distinct signal that the fruit is ripe.” Or perhaps the chlorophyll degradation products also serve a biological function for the banana. The amazingly stable catabolytes could help to prolong the viability of the ripening fruit.

Author: Bernhard Kräutler, University of Innsbruck (Austria), http://www.uibk.ac.at/organic/de/

Title: Blue Luminescence of Ripening Bananas

Angewandte Chemie International Edition 2008, 47, No. 46, doi: 10.1002/anie.200803189

Bernhard Kräutler | Angewandte Chemie
Further information:
http://pressroom.angewandte.org
http://www.uibk.ac.at/organic/de/

More articles from Life Sciences:

nachricht New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
29.05.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke
29.05.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>