Posts Tagged: taste
So pernicious is PTD that its occurrence can downgrade the value of the entire crop by a fourth or a third. Worse yet, PTD is only apparent after processing, roasting, grinding and brewing, and can occur long after the coffee has been shipped abroad.
Thought to be caused by chemicals produced by microbes that gain access to the coffee cherries by way of a stink bug called antestia, PTD has gained the attention of an international effort, called the potato taste project, that for two years has sought the cause and cure for the defect
Two undergraduate students at the University of California, Riverside, have played key roles in the potato taste project.
“Lauren Wong and Tony Truong made a key breakthrough discovery that led to our asking one of UC Riverside’s plant pathologists, James Borneman, to do a microbiome of coffee beans in Rwanda,” says Thomas Miller, a professor of entomology at UCR and one of the members of the international team working to mitigate the potential impact of the defect on Rwanda’s specialty coffee industry.
“We juxtaposed beans that had passed the stringent criteria against numerous batches of beans that had potato taste defect,” says Wong, who graduated in spring 2013 with a bachelor’s degree in biological sciences and is currently working in Miller’s lab. “When we roasted the beans, we found that all the potato taste defect microbes were killed.”
Truong examined whether the potato taste defect microbes can be manipulated to affect coffee taste.
“My experiment is a stepping stone to finding a solution for potato taste defect,” says Truong, who will graduate with a bachelor’s degree in biochemistry in 2015. “Are bacterial/fungal infections the source of the problem? Can the affected coffee beans be treated to remove the effects of potato taste defect? These are some of the questions I am exploring.”
Then, Miller stayed in Rwanda for two weeks that comprised meetings, workshops and numerous field trips. He has been in nearly daily email contact with Rwanda since.
“That visit helped us all get a better understanding of potato taste and its causes,” he says. “We gathered coffee bean samples for analysis in the United States and began collaborating with Rwandan scientists. We also assisted Rwanda in reaching out and making contact with people willing to help solve the potato taste defect problem.”
The culmination of the first two years of the PTD project will be a coffee summit on 1-2 April 2014 at NUR. The meeting is being organized by NUR and the Global Knowledge Initiative, a Washington DC, non-profit organization dedicated to finding solutions to problems in developing countries.
More information about PTD can be found at www.coffee.ucr.edu.
Umami is difficult to describe in just one word; it is a pleasant, hearty, savory, tongue-coating sensation. And because it is so complex - a taste imparted by glutamate, a type of amino acid, and ribonucleotides, including inosinate and guanylate, which occur naturally in many foods including meat, fish, vegetables and dairy products - the taste blends well with other tastes to round out the flavors. This is why it’s hard to describe the delicious flavor of chicken soup.
Umami is a relatively new concept to most Americans, but this taste has been known for more than 100 years in some parts of Europe and Japan, where chemist Kikunae Ikeda is credited with identifying the taste. Ikeda analyzed the active ingredients in kelp stock, a staple of Japanese cuisine, and discovered that the delectable taste was associated with glutamate. Glutamate is also present in other savory foods, including those used in Western cuisine, like tomatoes, mushrooms, asparagus, cheese and meat.Ikeda later developed and patented a method of making monosodium glutamate, or MSG, a processed additive that adds umami taste to food, much like sugar makes things taste sweet. In this country, MSG is not looked upon favorably. There are as many discussions against the use of MSG as there are for the use of MSG to flavor foods.
Hanne Siversten, a UC Davis specialist with the Department of Food Science and Technology explains, “MSG does not taste like much alone, but added to foods, it shows synergistic effects. This means that new flavors appear, as a reaction between MSG and the food itself.”
The taste of umami works much the same way. And since it is an experience naturally occurring from compounds found in many foods, you don’t have to add MSG to understand the taste. You probably eat umami-rich foods every day. Who doesn’t like their spaghetti sauce with a little parmesan cheese? Or cheese and bacon on their hamburger? These combinations ramp up the flavor of the whole meal. Check out the Umami Information Center (http://www.umamiinfo.com/), a great online resource for Umami information, facts and recipes.