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Olive oil, which is simply the oil extracted from the fruit of olive trees, has been cultivated for thousands of years across the Mediterranean Basin. Today, olive oil is steadily increasing in popularity across the globe due to its health benefits. Some studies suggest that long-term consumption of small amounts of olive oil may aid in a lower incidence of heart disease due to the chemicals polyphenol and oleocanthal, an antioxidant, obtained from the oil.

Bottom of the Barrel

The highest grade of olive oil, called extra-virgin, is an unrefined oil which contains a higher amount of natural vitamins and minerals found in olives. The International Olive Council (IOC) governs approximately 95% of international olive oil production and regulates the use of labels for olive oils. According to the IOC standard for extra-virgin olive oil, the oil must not contain more than 0.8% acidity and is judged to have superior taste and no sensory defects.

Of all varieties of olive oil, extra-virgin accounts for only about 10% of oils in major producing countries. Unfortunately, the United States is not a member of the IOC, and with only voluntary standards put in place by the USDA, Americans are often left with the “bottom of the barrel.” In a 2010 study performed by the University of California, Davis it was found that nearly 69% of supermarket oils marketed as “extra-virgin” were not actually extra-virgin according to IOC standards.

Migration Testing in Food Packaging

At CPG, we test olive oil, but not to determine its IOC grade. Instead, we use olive oil as a fatty food stimulant for migration testing in food packaging. Samples of food packaging, or plastic that is contact with food, such as conveyor systems, are immersed in olive oil for specified lengths of time.  The amount of extracted products from the plastic into the oil must be determined by accounting for the weight loss in the sample, corrected by the amount of absorbed olive oil into the sample. Typically, extraction with derivatization of the oil, followed by GC-MS, allows quantitative assessment of the amount of absorbed oil. In addition, GC-MS, along with LC-MS, can be used to quantify and identify individual species extracted by the oil from the plastic. Details of the requirements for food contacting materials in Europe can be found in EU No. 10/2011.

For more information, please visit our packaging analysis page.

An abandoned house or factory building is often associated with windows boarded up with plywood. Over time, glass windows can break due to neglect or vandalism, and the plywood boarding helps prevent rain, snow, and debris from entering the building. The appearance of plywood boarding, however, draws attention to the abandoned nature of the building, and can shield illicit activity inside the building from the eyes of neighbors and law enforcement.

Several communities have converted to polycarbonate sheets instead of plywood. Polycarbonate is a transparent plastic that is much tougher than glass, which will help against breakage, yet has the same appearance as glass, effectively improving the curb appeal and inhibiting illegal activities inside the property. The technique of using polycarbonate sheets is called ‘clear boarding,’ and is being mandated by Fannie Mae on its vacant properties. Polycarbonate is used for bullet-resistant glass found in banks and armored cars, as well as windows for airplanes, motorcycles, helicopters, and some screens for electronics. Polycarbonates were first found in the late 1800s, but finally commercialized in the 1950s. 

Two potential downsides to clear boarding are the cost, which can be upwards of 6 times as much as plywood, and challenges with entry by firefighters. The tough nature of polycarbonate requires firefighting personnel to cut through the polycarbonate enclosures with saws, rather than breaking them with axes. Proponents of clear boarding suggest that the reduced chance of property damage and illegal activities will offset the cost and reduce the likelihood of arson or accidental fires.

Recently there has been increasing concern with antibiotic resistant bacteria.  To a large extent, this increase can be attributed to over-subscription of antibiotics leading to evolved resistance of the bacteria.  At its worst, this heightened use of antibiotics has led to organisms such as Methicillin-resistant Staphylococcus aureus (MRSA), also known as a “super bug”.  The real issue behind this bug is that it can be present in hospitals and healthcare facilities where the most vulnerable population are present.  However, visually demonstrating this acquired resistance is not straightforward and therefore the message of being more judicious with antibiotics (and fully completing the prescribed course) can get lost. 

Researchers at Harvard University released a compelling video that allows one to watch the acquired resistance to antibiotics visually:

The Evolution of Bacteria on a "Mega-Plate" Petri Dish from Harvard Medical School on Vimeo.

Ever have a lump in your throat? You may have dysphagia, a medical condition whereby the patient has difficulty swallowing solids and liquids. There are multiple causes for dysphagia, ranging from gastroesophageal reflux to esophageal cancer. If not treated, pulmonary aspiration could occur when liquids enter the lungs by accident. Treatment of dysphagia depends on the source of the condition, but may be as simple as modifying swallowing behavior and changing diet, or it may require surgery for more complicated conditions. 

Artificial Throat Monitors Flow Behavior of Food

We have often discussed the rheology, or flow behavior, of food products on our web site, and how it relates to taste and consumer perception. Rheology of food can also play a role in dysphagia.  Thicker liquids may be easier to swallow for dysphagia patients. To test this theory, researchers at the University of Cambridge, headed by Professor Malcolm Mackley, constructed an artificial throat to monitor flow behavior of liquids of varying viscosities when ‘swallowed’ by the throat.

Dialysis tubing was used to model the throat, with rollers and counterweights representing the tongue. Optical access allowed the monitoring of the residence time of a bolus of fluid makes its way past the tongue and epiglottis. 

Various fluids containing common thickeners used in the food industry (xantham gum, nutilis) were investigated. Shear and extensional rheometry were performed, since both these modes of deformation would be present in the throat, and provided key viscoelastic properties for the fluids.

The authors concluded that the viscoelastic properties of the test fluids played a role in the amount of time it took for the fluid to travel from the epiglottis to the airway, which could affect aspiration and patient comfort. 

Our pets may be difficult to train, but researchers at the University of Toronto have developed a peptide-based hydrogel system that helps encourage skin cells to crawl towards each other, leading to a more rapid closure on chronic wounds commonly found in diabetic patients. 

With their hydrogel system, wounds closed in less than 2 weeks. The peptide-hydrogel system promotes survival of the cells, and gives the cells a substrate to crawl over to help with wound closure.

I wonder if it works on dogs?

As the holiday baking season approaches, we are naturally thinking about caramel. At CPG, we have tested caramels and other food products in order to determine why some of these products have better ‘mouth-feel’ than others based on rheological assessment, a science sometimes termed ‘psychorheology’.

Chemistry of Caramel

The discussion today, however, has to do with the chemistry of caramel. Caramel is the result of a decomposition reaction of sucrose (also known as table sugar) when it is heated to its decomposition temperature, between 170-186 C. Sucrose is a disaccharide made up of glucose and fructose. When it decomposes, water is released through a condensation reaction, along with glucose initially. Additional polymerization and isomerization then occurs, resulting in multiple high molecular weight compounds, as well as lower molecular weight compounds.

The lower molecular weight compounds are more volatile, and generate the characteristic aroma associated with caramels, including ethyl acetate (fruity/pineapple), furans (almonds), diacetyl (butter flavor), and maltols (toasted bread).

Sucrose, on the other hand, has a very mild odor, often not detectable due to its low volatility. The distinctive caramel smell is familiar to many polymer analysts who either deliberately or inadvertently decompose polysaccharides, generating many of the same compounds found in caramel.

The chemical reactions that occur at this stage are not really well known, even to this day. It is known that dimerization occurs, whereby two sugars reaction to form a single molecule containing three cyclical structures and a dianhydride. These structures are then believed to undergo hydrolysis reactions that product a compound called caramelan (C₁₂H₁₂O₉), caramelen (C₃₆H₁₈O₂₄) and. caramelin (C₂₄H₂₆O₁₃), depending on the amount of water lost. These compounds form particles that have color centers believed to result in the color changes in caramel.

In addition to these reactions, free radicals are produced, which play a role in the tacky nature of caramels due to enhanced van der Waal’s interactions.

So although a great deal is not known about the chemical reactions in caramel, we can all perform our own enthusiastic home study on this wonderful cooking mistake.