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Banana

Photo Credit: Thomas Abbs (tabsinthe/Flickr)

Photo Credit: Thomas Abbs (tabsinthe/Flickr)

Among fruits, bananas enjoy huge popularity. The Market and Policy Analyses of Raw Materials, Horticulture and Tropical (RAMHOT) Products Team even reported that within the U.S. in 2012, per capita banana consumption was calculated at 13.8kg [1]. The humble banana even reigns as the main fruit in international trade, according to the Food and Agriculture Organization of the United Nations (FAO) [2]. But as a flavor? Banana candies are often the last flavor left in the bowl.

The disparity between the pleasant and sickening feelings which banana flavoring can invoke lies in the intricacy of banana flavor chemistry. The fruit itself contains a mixture of volatile compounds that are responsible for its characteristic flavor. Up to 42 molecules have been identified to contribute to the aromatic profile of bananas [2]. Each of these molecules, when isolated, has been reported to give off their own unique scent [2,3]. Most of the scents are described as floral, sweet, and generally fruity, which are expected when analyzing aroma compounds derived from bananas. However, there are a few volatile compounds that emit odors not usually associated with bananas. For instance, eugenol, one of the significantly abundant aromatic compounds found in bananas, smells spicy, like cinnamon [2,3].

Of all the volatile compounds detected in bananas and analyzed, one stands out as the banana flavor molecule: isoamyl acetate. With a scent often described as “over-ripe bananas”, pure solutions of isoamyl acetate are sold as “banana oil”. Isoamyl acetate is widely used as a flavorant to confer that over-ripe banana flavor in foods. Yet, as many can attest, pure “banana flavor” tastes awful, nothing like the actual fruit. Despite its presence in the banana itself, how does the banana-flavor molecule miss the mark so badly in candy?

Isoamyl Acetate

Chemical complexity is one explanation, as there are 30-40 other aroma compounds that contribute to natural banana flavor. Additionally, in a ripe banana, although isoamyl acetate is one of the key molecules in banana aromatics, it is found in small amounts compared to the other volatile compounds [2,3]. Yet, even though isoamyl acetate is not the most abundant compound in the aromatic profile of bananas, it is a heady flavor on its own: this molecule can be tasted in concentrations as low as 2 parts per million [4].

So, maybe a banana-flavored Laffy Taffy contains a higher concentration of isoamyl acetate than an actual banana. Until scientists and flavor chemists figure out how to make banana-flavored foods actually taste like bananas, at least the yellow Laffy Taffy has its small but dedicated fan base.

References cited

  1. Banana Market Review and Banana Statistics 2012-2013. (2014). Retrieved October 2, 2014.
  2. Jordán MJ, Tandon K, Shaw PE, Goodner KL. Aromatic profile of aqueous banana essence and banana fruit by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). J Agric Food Chem. Oct 2001;49(10):4813-7.
  3. Pino J, Febles Y. Odour-active compounds in banana fruit cv. Giant Cavendish. Food Chemistry. Mar 2013;141(2013):795-801.
  4. Bilbrey, J. (2014, July 30). Isoamyl acetate. Retrieved September 28, 2014.

Alice PhungAbout the author: Alice Phung once had her sights set on an English degree, but eventually switched over to chemistry and hasn’t looked back since.

Read more by Alice Phung


Photo credit: Chris Battaglia (photog63/Flickr)

Hazelnut

Photo credit: Chris Battaglia (photog63/Flickr)

Hazelnuts may not be as popular as other nuts in the U.S., but they have quite the culinary versatility, enjoyed in pralines, Nutella, and even as themselves. These nuts grow on hazel trees, of the genus Corylus. Depending on the plant species and nut shape, hazelnut also refers to the filbert nut or cobnut. Filbert nuts have an elongated shape that tapers into a “beak”, and are found on the Filbert (C. maxima), Colchican Filbert (C. colchica), and Turkish Hazel (C. colurna). Cobnuts are generally rounder, and grow on the American Hazelnut (C. americana) and the more commercially recognized Common Hazel (C. avellana) [1].

Whether in the form of a nut, essence, or oil, hazelnuts owe their sweet, buttery flavor profile to the molecule filbertone. Interestingly, filbertone can be used to test for the authenticity of olive oil. Olive oils are sometimes cheapened by mixing in hazelnut oil [2]. As filbertone is one of the components of hazelnut oil, testing for its presence can determine whether or not a sample of olive oil is impure [3]. Although hazelnut oil is less expensive compared to olive oil, it has a strong, robust flavor that makes it a great substitute in salad dressings and baked goods.

Filbertone_Hazelnut-02

Like many nuts, hazelnuts are a good source of protein and monounsaturated fats. Further, they contain a significant amount of thiamine, various B vitamins, and especially vitamin E [4]. Need another reason to try out hazelnuts this month? The warm, rich, velvety taste of roasted hazelnuts in decadent truffles or comforting lattes has a way of slowing down time. Try it for yourself.


References Cited

  1. Flora of North America: Corylus. <http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=108088>
  2. Arlorio M.; Coisson JD; Bordiga M.; Garino C.; et al. “Olive Oil Adulterated with Hazelnut Oils: Simulation to Identify Possible Risks to Allergic Consumers.” Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2010 Jan; 27(1):11-8. doi: 10.1080/02652030903225799.
  3. Flores, G.; Ruiz del Castillo, M.L.; Blanch, G.P.; Herraiz, M. “Detection of the Adulteration of Olive Oils by Solid Phase Microextraction and Multidimensional Gas Chromatography”. Food Chemistry, 2006 Jul; 97(2): 336–342.
  4. Nutritional Value of Hazelnuts. < http://www.aboutnuts.com/en/encyclopedia/hazelnuts>

Alice PhungAbout the author: Alice Phung once had her sights set on an English degree, but eventually switched over to chemistry and hasn’t looked back since.

Read more by Alice Phung


Peppermint

Peppermints_LisaBunchofpants

Photo credit: Lisa Bunchofpants (bunchofpants/Flickr)

Seasonal winter treats somehow seem incomplete unless they are imbued with a frosty, peppermint flavor. This is easily accomplished by enhancing the recipe with peppermint oil or peppermint extract, cultivated from the leaves of the peppermint plant. This plant’s scientific name is Mentha x piperita, the “x” indicating that it is a hybrid mint, formed by crossing watermint (Mentha aquatica) and spearmint (Mentha spicata). As a hybrid plant, peppermint is sterile, unable to produce seeds. Instead, it reproduces via rhizomes, bulbous plant masses found underground that are very similar to ginger and turmeric roots. Like many rhizomes, peppermint rhizomes can be planted almost anywhere, growing quickly once sprouted. For this reason, the peppermint plant is listed as invasive in Australia, the Galapagos Islands, New Zealand, and the Great Lakes region of the U.S. [1].

Peppermint oils and extracts get their characteristic Christmas-in-your-mouth flavor from their two main constituents, menthol and menthone. Of the two, menthol may be the more recognizable: When ingested, applied topically, or inhaled, menthol triggers cold-response sensory receptors, which cause that familiar cooling sensation [2]. You may have experienced this from chewing minty gums, using toothpaste, or applying Bengay to sore muscles.

PeppermintFlavors

Menthone is structurally related to menthol, but it affects a different sense in peppermint-flavored treats. This molecule gives rise to the icy, minty scent reminiscent of evergreen winters. Its distinctive fragrant property makes it popular in perfumes, cosmetics, and scented oils.

If you indulge in something peppermint this month, take some time to appreciate the menthol and menthone that makes this essence a holiday classic. Feel the sharp chill in your mouth while you bask in the warmth of a heated room. Take in the scent of cool mint while the winter wind outside whirls away. ‘Tis the season.

References Cited

  1. Pacific Island Ecosystems at Risk: Mentha x piperita <http://www.hear.org/pier/species/mentha_x_piperita.htm>.
  2. Knowlton, Wendy M., et al. “A Sensory-Labeled Line For Cold: TRPM8-Expressing Sensory Neurons Define The Cellular Basis For Cold, Cold Pain, And Cooling-Mediated Analgesia.” Journal Of Neuroscience 33.7 (2013): 2837-2848. Academic Search Complete. Web. 23 Nov. 2013.

Alice PhungAbout the author: Alice Phung once had her sights set on an English degree, but eventually switched over to chemistry and hasn’t looked back since.

Read more by Alice Phung