Tag Archives: bananas

Coat fruit with silk to keep it fresh

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A May 6, 2016 news item on ScienceDaily describes a way to keep fruit fresh without refrigeration,

Half of the world’s fruit and vegetable crops are lost during the food supply chain, due mostly to premature deterioration of these perishable foods, according to the Food and Agriculture Organization (FAO) of the United Nations.

Tufts University biomedical engineers have demonstrated that fruits can stay fresh for more than a week without refrigeration if they are coated in an odorless, biocompatible silk solution so thin as to be virtually invisible. The approach is a promising alternative for preservation of delicate foods using a naturally derived material and a water-based manufacturing process.

A May 6, 2016 Tufts University news release (also on EurekAlert), which originated the news item, describes the work,

Silk’s unique crystalline structure makes it one of nature’s toughest materials. Fibroin, an insoluble protein found in silk, has a remarkable ability to stabilize and protect other materials while being fully biocompatible and biodegradable.

For the study, researchers dipped freshly picked strawberries in a solution of 1 percent silk fibroin protein; the coating process was repeated up to four times.  The silk fibroin-coated fruits were then treated for varying amounts of time with water vapor under vacuum (water annealed) to create varying percentages of crystalline beta-sheets in the coating. The longer the exposure, the higher the percentage of beta-sheets and the more robust the fibroin coating. The coating was 27 to 35 microns thick.

The strawberries were then stored at room temperature. Uncoated berries were compared over time with berries dipped in varying numbers of coats of silk that had been annealed for different periods of time. At seven days, the berries coated with the higher beta-sheet silk were still juicy and firm while the uncoated berries were dehydrated and discolored.

Tests showed that the silk coating prolonged the freshness of the fruits by slowing fruit respiration, extending fruit firmness and preventing decay.

“The beta-sheet content of the edible silk fibroin coatings made the strawberries less permeable to carbon dioxide and oxygen. We saw a statistically significant delay in the decay of the fruit,” said senior and corresponding study author Fiorenzo G. Omenetto, Ph.D. Omenetto is the Frank C. Doble Professor in the Department of Biomedical Engineering and also has appointments in the Department of Electrical Engineering and in the Department of Physics in the School of Arts and Sciences.

Similar experiments were performed on bananas, which, unlike strawberries, are able to ripen after they are harvested. The silk coating decreased the bananas’ ripening rate compared with uncoated controls and added firmness to the fruit by preventing softening of the peel.

The thin, odorless silk coating did not affect fruit texture.  Taste was not studied.

“Various therapeutic agents could be easily added to the water-based silk solution used for the coatings, so we could potentially both preserve and add therapeutic function to consumable goods without the need for complex chemistries,” said the study’s first author, Benedetto Marelli, Ph.D., formerly a post-doctoral associate in the Omenetto laboratory and now at MIT.

Here’s a link to and a citation for the paper,

Silk Fibroin as Edible Coating for Perishable Food Preservation by B. Marelli, M. A. Brenckle, D. L. Kaplan & F. G. Omenetto. Scientific Reports 6, Article number: 25263 (2016) doi:10.1038/srep25263 Published online: 06 May 2016

This is an open access paper.

The shorter, the better for cellulose nanofibres

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Cellulose nanomaterials can be derived from any number of plants. In Canada, we tend to think of our trees first but there are other sources such as cotton, bananas, hemp, carrots, and more.

In anticipation that cellulose nanofibres will become increasingly important constituents of various products and having noticed a resemblance to carbon nanotubes, scientists in Switzerland have investigated the possible toxicity issues according to a May 7, 2015 news item on Nanowerk,

Plant-based cellulose nanofibres do not pose a short-term health risk, especially short fibres, shows a study conducted in the context of National Research Programme “Opportunities and Risks of Nanomaterials” (NRP 64). But lung cells are less efficient in eliminating longer fibres.

Similar to carbon nanotubes that are used in cycling helmets and tennis rackets, cellulose nanofibres are extremely light while being extremely tear-resistant. But their production is significantly cheaper because they can be manufactured from plant waste of cotton or banana plants. “It is only a matter of time before they prevail on the market,” says Christoph Weder of the Adolphe Merkle Institute at the University of Fribourg [Switzerland].

A May 7, 2015 Swiss National Science Foundation (SNSF) press release, which originated the news item, provides more detail,

In the context of the National Research Programme “Opportunities and Risks of Nanomaterials” (NRP 64), he collaborated with the team of Barbara Rothen-Rutishauser to examine whether these plant-based nanofibres are harmful to the lungs when inhaled. The investigation does not rely on animal testing; instead the group of Rothen-Rutishauser developped a complex 3D lung cell system to simulate the surface of the lungs by using various human cell cultures in the test tube.

The shorter, the better

Their results (*) show that cellulose nanofibres are not harmful: the analysed lung cells showed no signs of acute stress or inflammation. But there were clear differences between short and long fibres: the lung cell system efficiently eliminated short fibres while longer fibres stayed on the cell surface.

“The testing only lasted two days because we cannot grow the cell cultures for longer,” explains Barbara Rothen-Rutishauser. For this reason, she adds, they cannot say if the longer fibre may have a negative impact on the lungs in the long term. Tests involving carbon nanotubes have shown that lung cells lose their equilibrium when they are faced with long tubes because they try to incorporate them into the cell to no avail. “This frustrated phagocytosis can trigger an inflammatory reaction,” says Rothen-Rutishauser. To avoid potential harm, she recommends that companies developing products with nanofibres use fibres that are short and pliable instead of long and rigid.

National Research Programme “Opportunities and Risks of Nanomaterials” (NRP 64)

The National Research Programme “Opportunities and Risks of Nanomaterials” (NRP 64) hopes to be able to bridge the gaps in our current knowledge on nanomaterials. Opportunities and risks for human health and the environment in relation to the manufacture, use and disposal of synthetic nanomaterials need to be better understood. The projects started their research work in December 2010.

I have a link to and a citation for the paper (Note: They use the term cellulose nanocrystals in the paper’s title),

Fate of Cellulose Nanocrystal Aerosols Deposited on the Lung Cell Surface In Vitro by Carola Endes, Silvana Mueller, Calum Kinnear, Dimitri Vanhecke, E. Johan Foster, Alke Petri-Fink, Christoph Weder, Martin J. D. Clift, and Barbara Rothen-Rutishauser. Biomacromolecules, 2015, 16 (4), pp 1267–1275 DOI: 10.1021/acs.biomac.5b00055 Publication Date (Web): March 19, 2015

Copyright © 2015 American Chemical Society

While tracking down the 2015 paper, I found this from 2011,

Investigating the Interaction of Cellulose Nanofibers Derived from Cotton with a Sophisticated 3D Human Lung Cell Coculture by Martin J. D. Clift, E. Johan Foster, Dimitri Vanhecke, Daniel Studer, Peter Wick, Peter Gehr, Barbara Rothen-Rutishauser, and Christoph Weder. Biomacromolecules, 2011, 12 (10), pp 3666–3673 DOI: 10.1021/bm200865j Publication Date (Web): August 16, 2011

Copyright © 2011 American Chemical Society

Both papers are behind a paywall.

NanoCelluComp (nanocellulose composites) goes to JEC Composites Show and Conference in Paris (France)

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NanoCelluComp (nanocellulose composites), a European Commission-funded project under the European Union’s 7th Framework Programme, which is entering its final stage (2011 – 2014) will make an appearance (Exhibition Stand D83) at the JEC 2014 Composites Show and Conferences in Paris (France), 11-13th March, 2014.

I  profileded NanoCelluComp in a March 7, 2013 posting where I included excerpts from the project’s 4th newsletter. The 5th (August 2013) newsletter is available here. There is also a project flyer (PDF), which provides some additional insight into why the project was developed and what NanoCellulComp was attempting to accomplish,

Food processing of vegetables produces billions of tonnes of fibrous waste. The cellulose fibres contained within this waste have superior structural properties that with ‘green’ chemistry can be put to much better use. Composites containing cellulose extracted from carrot waste have already been incorporated in lightweight products such as fishing rods and steering wheels.

This material – Curran – while exhibiting good structural properties, does not have the strength of glass or carbon fibre reinforced plastics (GFRP and CFRP) and is further disadvantaged due to limited processability.

The NanoCelluComp Process Improving on Curran through:

Liberating microfibrillated cellulose (nanocellulose) from vegetable waste streams utilising an aqueous based process (thus decreasing energy consumption, and avoiding volatile chemicals).
 Improving mechanical properties by the controlled alignment and cross linking of nanocellulose fibrils.
 Combining the resultant fibres with bio-based resins to produce a 100% bio-composite (thus decreasing use of petroleum-based products).
 Ensuring compatibility of the bio-composite with current manufacturing processes (e.g. injection moulding, hand lay-up).
 Investigating the sustainability of the above processes and materials, compared to existing materials, through a full life-cycle assessment (LCA) and identifying promising application fields.

Most of the ‘nanocellulose’ material that I’ve covered has been focused on derivations from forest products however there is one other team (that I know of) led by researcher Alcides Leão of Brazil examining the possible uses of nanocellulose derived from pineapples and bananas. On that note, my June 13, 2011 posting titled: Transcript of nanocellulose fibre podcast interview with Alcides Leão, Ph.D., from São Paulo State University and/or my March 28, 2011 posting titled: Nanocellulose fibres, pineapples, bananas, and cars may be of interest.

Brazil, Canada, and an innovation, science, and technology forum in Vancouver (Canada)

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The Brazil-Canada Chamber of Commerce (BCCC) is presenting, in partnership with Simon Fraser University’s (SFU) Beedie School of Business, an all-morning forum on June 17, 2013. From the SFU Vancouver Events: June 14 – 21, 2013 announcement (Note: Links have been removed),

Monday, June 17 [2013]

Brazil-Canada Business, Innovation, Science, and Technology Forum

Time: 8-11:30am

Place: Segal Graduate Business School, 500 Granville St.

Cost: $35-70, register online

Join us for a morning focused on Business Innovation and Science & Tecnology opportunities in the Brazilian economy. The opening speakers, Ambassador Sergio Florencio, Consul General and Dr. Jeremy Hall will provide an overview of the landscape in Brazil. The panel discussion includes industry leaders who have piloted extensive business in Brazil specifically in the agriculture, mining and infrastructure fields: Marcelo Sarkis, Heenan Blaikie; Ray Castelli, Weatherhaven and Rogerio Tippe, Javelin Partners. If you are interested in conducting business in Brazil and would like to understand more about the dynamics of the Brazilian economy and how businesses operate, please register now.

If the event is about business, innovation, science, and technology, it seems curious the only mentions of science and/or technology in the event description are confined to a few of the panelists’ interests in agriculture, mining, and whatever they mean by infrastructure.

Brazil is one of the BRICS (Brazil, Russia,India, China, and South Africa) countries and, from what I understand, this very loose coalition is eager to take a leadership position vis à vis science, technology, and innovation supplanting the dominance of the US, Japan, and the European Union.

In the early 1990s, I wrote a paper about science and technology transfer and noted that Brazil was entering a new period of development after years of the country’s science and technology efforts (scientists) being isolated from the rest of the world in a failed  attempt to create a powerhouse international enterprise.

Some 20 years later, the decision to join the rest of the science and technology world seems to have been successful. Brazil is set to host the 2014 World Cup for soccer (or, as most of the world calls it, football) and the summer Olympics in 2016. (Sports are often correlated with science and technology advances.) I don’t believe any other country has ever attempted to host two such large international sports events within two years of each other. That’s a pretty confident attitude.

There are two areas of science and technology research in Brazil that are of particular interest to me, brain research and the work on cellulose nanocrystals (CNC), also known as, nanocrystalline cellulose (NCC).

While the focus was on Miguel Nicolelis and Duke University (US), the recent announcement of brain-to-brain communication via the Internet featured a research facility in Brazil (from my Mar. 4, 2013 posting),

Miguel Nicolelis, a professor at Duke University, has been making international headlines lately with two brain projects. The first one about implanting a brain chip that allows rats to perceive infrared light was mentioned in my Feb. 15, 2013 posting. The latest project is a brain-to-brain (rats) communication project as per a Feb. 28, 2013 news release on *EurekAlert,

Researchers have electronically linked the brains of pairs of rats for the first time, enabling them to communicate directly to solve simple behavioral puzzles. A further test of this work successfully linked the brains of two animals thousands of miles apart—one in Durham, N.C., and one in Natal, Brazil.

The results of these projects suggest the future potential for linking multiple brains to form what the research team is calling an “organic computer,” which could allow sharing of motor and sensory information among groups of animals. The study was published Feb. 28, 2013, in the journal Scientific Reports.

“Our previous studies with brain-machine interfaces had convinced us that the rat brain was much more plastic than we had previously thought,” said Miguel Nicolelis, M.D., PhD, lead author of the publication and professor of neurobiology at Duke University School of Medicine. “In those experiments, the rat brain was able to adapt easily to accept input from devices outside the body and even learn how to process invisible infrared light generated by an artificial sensor. So, the question we asked was, ‘if the brain could assimilate signals from artificial sensors, could it also assimilate information input from sensors from a different body?’”

One of Nicolelis’s other goals is to have someone with quadriplegia kick the opening ball for the Brazil-hosted 2014 World Cup (Walk Again Project). From my Mar. 16, 2012 posting,

It is the exoskeleton described on the Walk Again Project home page that Nicolelis is hoping will enable a young Brazilian quadriplegic to deliver the opening kick for the 2014 World Cup (soccer/football) in Brazil.

Moving on to the other area of interest, CNC research , which in Canada is discussed in terms of the forestry industry (I’ve blogged about this extensively, the search term NCC should fetch most if not all of my postings on the topic), is taking a different tack in Brazil where the focus is on pineapple and banana fibres. My Mar. 28, 20111 posting (Nanocellulose fibres, pineapples, bananas, and cars) focuses on cellulose and plastic,

Brazilian researchers are working on ways to use nanocellulose fibres from various plants to reinforce plastics in the automotive industry. From the March 28, 2011 news item on Nanowerk,

Study leader Alcides Leão, Ph.D., said the fibers used to reinforce the new plastics may come from delicate fruits like bananas and pineapples, but they are super strong. Some of these so-called nano-cellulose fibers are almost as stiff as Kevlar, the renowned super-strong material used in armor and bulletproof vests. Unlike Kevlar and other traditional plastics, which are made from petroleum or natural gas, nano-cellulose fibers are completely renewable.

My second and, to date, only other posting (June 16, 2011) about the work in Brazil features a transcript of an interview with CNC researcher, Alcides Leão.

Finally, I have a few factoids which I will tie together, loosely, and try to show how they relate to this forum. First, São Paulo, Brazil hosts the world’s second oldest and one of its most important biennial visual arts events. (BTW, the next one, Bienal de São Paulo,  is in 2014.) Second, the recent Council of Canadian Academies assessment, State of Science and Technology in Canada, 2012, stated that Canada rates very highly in six areas, one of those areas being the Visual and Performing Arts. Admittedly Canada’s prominence in the visual and performing is fueled largely by efforts in Québec (as per the assessment), still, one would think there might be some value in trying to include that sector in this  forum and encourage the local visual and performing arts technology industry to make connections with the Brazilian industry.

Finally for those of you who have persisted, here’s the link to buy tickets for the June 17, 2012 forum.

ETA June 21, 2013: The protests in Brazil have attracted worldwide attention and according to a June 21,2013 posting by Dillon Rand on Salon.com there are: 5 signs Brazil’s’ not ready to host the World Cup.

Is chocolate disappearing?

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It looks like the cacao plant used for chocolate production is at risk of being wiped out. Grrlscientist at the Guardian science blogs featured the story in her Jan. 11, 2012 posting.

… despite chocolate’s popularity in the United States and Europe, the cacao plant is in trouble. …

The most common way of growing cacao is in a monoculture, the same way that corn is grown, which makes plants much more susceptible to a plethora of diseases and pest infestations, says Dr Almeda [botanist Frank Almeda, senior curator at the California Academy of Sciences]. Making things worse, cacao farmers make less than one dollar a day, so cultivating cacao isn’t even economically feasible, so farmers are abandoning their cacao plantations.

Here’s a video from the California Academy of Sciences about chocolate,

Grrlscientist mentions corn as another food which is monoculture-cultivated and I’m going add banana as another one of these monoculture food plants and that, too, is in danger, not for the first time. (I’m not sure about whether corn is in immediate danger or not.) There’s a type of banana that we no longer eat, Gros Michel. Our grandparents did and, by all accounts, it was a better tasting banana than the one we have now but it was wiped out by disease.

Agribusiness interests found an alternative, the Cavendish banana, which is now in danger of being wiped out. (What is that saying about repeating the practices that you got into trouble in the first place and expecting a different result is the definition of insanity?) There’s  lots of information about the banana situation on the web and I found this US National Public Radio (NPR) interview from July 22, 2011 with Dan Koeppel, science writer and author of “Banana: The Fate of the Fruit that Changed the World,” which features a transcript of the interview, as well as, the audio file.

I know I don’t usually write about this kind of thing but 20 years ago when I was completing my undergraduate degree, I took a course where we discussed the issue of monoculture and the danger of relying on one species of food plant , and just couldn’t resist writing about this any longer.