Wednesday, November 17, 2010

Laurino: a great liquor to drink at the end of a great meal!


A few weeks ago, during some gardening I had to cut some branches of an old laurus nobilis tree I have in my garden and since I collect several leaves, I said to myself: why not preparing a good liquor?? So I started to...
If you look at the chemical composition of the essential oil of laurus nobilis, the main compounds identified are: 1,8-cineole, trans-sabinene hydrate, α-terpinylacetate , methyleugenol , sabinene, eugenol and α-pinene. Of course the amount of these components depends on the time in which you harvest the leaves and the time in which I picked the leaves was not the perfect time to have the maximum concentration of these compounds, by the way, it is good to try and at the end the result was fantastic. Here I leave you the recipe:
1 L of 95° alcohol
50 leaves of laurus nobilis
1,5 L of water
250 g of sugar
Put the leaves in alcohol and keep them out of light in a dry place for 10 days. After dissolve the sugar in water and add this solution to the alcoholic extract, filter and put in bottles. Start drinking "cold" after 10 days. When I say "cold". I say you should keep the bottle in the freezer!

Monday, June 7, 2010

Something about the histamine fish poisoning


After several months of being away from my blog, due to lots of work to do, I am back and happy, because, to be honest, I have been missing to write and discuss about chemistry! This week end I was talking to some students about the role of the chemists in the food control, quality control of food production and research and development in the food industry. I introduced the HACCP system and reported some examples about food control in some types of industries. One of the most interesting topics, was about the histamine fish poisoning. Histamine fish poisoning (or Scombroid poisoning) is a type of food poisoning caused by elevated levels of histamine being present in the fish. Naturally occurring bacteria in fish produce an enzyme which converts histidine in the fish to histamine. Histamine fish poisoning usually occurs in certain species of fish, such as tuna, sardines, mackerel, swordfish and marlin, because of their high content of histidine. Histamine fish poisoning occurs very quickly after eating the fish, usually within 30 minutes to a few hours.
Common signs of histamine fish poisoning include: a peppery taste sensation, skin rash, headaches, dizziness and itching of the skin.
In some cases nausea, vomiting and diarrhoea may also occur. Symptoms usually last for 4 to 6 hours and rarely exceed one day. It is easily treated with an antihistamine.
Histamine is not destroyed by cooking. Therefore, the best way to keep histamine at a minimum is to ensure proper temperature control and good practices and hygienical conditions during the preparation of fish.
In some cases, low levels of histamine may already be present in the fish when you receive it. To stop it increasing to levels of concern, you should always:
1) purchase from reputable suppliers who store the fish on ice or under refrigeration;
2) receive product at refrigerated temperatures (<5°C);
3) place the fish under refrigeration as soon as it is received;
4) keep the fish at refrigerated temperatures when not being used; and
5) if the fish is frozen, thaw the fish under refrigeration.
When displaying fish for sale, always ensure there is enough ice on the product and refrigeration units are set at a temperature less than 5°C.
If you produce fish products (anchovies under oil, with capers, or with tomatos and other types of food), follow good hygiene practices:
1) Keep the surfaces and all the things you use clean;
2) Dress clean coats and use protections for hands to avoid the risk of contaminations.
Anyway, there is a big world about the fish industry and several things can be written, I think I will be back to this argument, in the future, may be with some recipes about fish!

Thursday, January 28, 2010

Nanomaterials and cosmetics: some news

In the last days I worked on the main topics introduced by the new european regulation on cosmetic products, the EU regulation number 1223/2009, recently adopted by the european parliament. This regulation has been finally done after more than 30 years of modification and integration of the previous european directive 76/768/CEE, regulating the production and commercialization of cosmetic products. The EU regulation n° 1223/2009 finally governs the use of nanomaterials in cosmetics. The use of nanomaterials and the growth of nanotechnology in the last years was a success and it regards different types of industries, from electronic and materials industries, to pharmaceutical and cosmetic industries. Nanomaterials are already in different types of cosmetics, even if there are not so many studies about the toxicological properties of these materials. Nanomaterials are defined as insoluble or biopersistant and intentionally manufactured materials with one or more external dimensions, or an internal structure, on the scale from 1 to 100 nm. It is easy to imagine how different could be the interaction of these materials and the skin and the possible absorption or migration through the skin. The high value of surface/volume ratio makes these materials good to catalyze different reactions and increase the production of reactive oxygen species (ROS), including free radicals. It may results in oxidative stress, inflammation and consequent damage to proteins, membranes and DNA. In cosmetics there could be nanoparticles of metal oxides like titanium dioxide or zinc oxide used as sunscreens in different cosmetics or there could be nanomaterials that loose their structure upon the application on the skin, like as liposomes and nanoemulsions. Anyway, since there are not so many studies about them regarding their toxicological activity, the new regulation takes the obligations to the producers to evaluate the safety of the nanomaterials they use to formulate their cosmetics and gives to them the obligation to communicate their use and the amount of the nanomaterials used as well as all the informations about scientific studies on the safety of these materials and the exposure conditions. The regulation has been made for ensuring a high level of protection of human health!

Monday, January 25, 2010

A link to carbonated fruits!

I am really sorry with all my friends and readers of this blog, since in the previous posts I wrote just a few lines, but, believe me, I was super busy with work in the last months and it is not easy expecially when, like me, you do several things, mostly of them so different and you wanna do them at the same time!
In the previous post, I forgot to put a link to some recipes and a scientific explaination about carbonated fruits. Here, I will leave you with a link, in which you can find nice recipes of carbonated fruits, made with a siphon bottle. Enjoy reading it and hope to be back to you soon, with some other chemical news!

Saturday, January 9, 2010

Siphon cakes, mousses and creams

A few days ago I was at the restaurant with some friends and at the end of the meal when we had to take the dessert I was tempted by the "Green tea siphon cake". I was guessing it was a great idea, but I decided to take the more conventional tiramisù. Anyway, my brother tried the siphon cake, so I couldnt resist to take at least a little piece from his plate and I discovered it was very soft and with an amazing taste. By doing a research on Internet, I discovered the Siphon is widely used to make cakes, desserts, mousses, creams and other different types of meals. By modulating temperature, and pressure of gases (carbon dioxide mainly), it is possible to control the thickness of a cream or the texture of carbonated fruits. Every day we can say the future of gastronomy belongs to chemistry!