In the last 12 years, researchers have isolated taste receptors for sweet – as well as the lesser understood basic taste – umami. Umami (pronounced: ew-mommy) is often at the heart of intuitive succulent cooking. Grandmothers in southern Italy, for example, toss a handful of cherry tomatoes into a clear broth, or slip the rind of parmesan cheese into a pot of simmering beans.

“Without consciously knowing what they're doing, they add the taste of umami to the dish,” says Brooklyn-based cookbook author Rozanne Gold.

Wild mushrooms, fresh picked corn, dried seaweed and fish sauce all have lots of savory umami taste, and high levels of an amino acid called glutamate. Glutamic acid tips off the taste buds, and then an umami alert rushes to the brain.

Umami deepens flavor and adds meatiness, says Gold, who calls herself the "Diva of Simplicity."

Her latest book is Radically Simple: Brilliant Flavors with Breathtaking Ease.

“When you only have three ingredients to play with each one really counts, so instinctively I work with foods that are umami rich,” she said. “What MSG does for a dish, that already exists naturally in some foods.”

The concept is age-old but a Japanese chemist, Kikunae Ikeda coined the term “umami” in the early 1900s. Everyday taste testers struggle to categorize umami, says neuroscientist Alexander Bachmanov, because the taste rarely stands alone. And that, he says, may explain why a scientist, not a chef, finally gave umami a name.

You can put a sugar cube on your tongue to sample pure sweet, or lick sodium chloride to explain salty. Umami is harder to single out, says Bachmanov, a researcher at the Monell Chemical Senses Center in Philadelphia.

“If it's glutamic acid, it will also have some sourness in addition to umami. If it is monosodium glutamate (MSG), it will have a little bit of saltiness in addition to umami,” he said.

That something else, is now considered the fifth taste. When scientists isolated the first umami taste receptor in 2000, umami officially joined the big four–sour, salty bitter and sweet.

Bachmanov says our taste buds are “tuned-up” to taste glutamic acids, and there's likely an evolutionary reason why most people perceive umami as pleasant.

Our sense of taste is like a detection system, constantly analyzing and helping us decide whether to eat or avoid a food. Glutamic acid–the tip-off for the umami taste–is a building block of protein.

“If a food is sweet, it likely contains carbohydrates. If it has umami taste is probably has protein. Our body gets the indication that the food contains protein, that it's nutritious, good for us,” Bachmanov said.

Pepin is famous for going to work after just 9 weeks of training, finding 52 scats in a single day.

This candidate must:

• Follow orders
• Be rough, energetic and adventurous
• Travel around the world
• Find things that are nearly impossible to see
• Be willing to ride in the back of a truck and wear a collar
• Run long distances
• Be a fast learner
• Be obsessed with toys
• Be willing to sniff poop
• Get compensated in rope-tugging with benefits such as scratches and belly rubs
• Come from a background of animal shelter living

Yes, the only qualified species is: Dog.

The Job: Working Dog for Conservation.

I saw these dogs in action at the Wildlife Conservation Network (WCN) Expo in San Francisco in October. The organization, Working Dogs for Conservation and their dog demo with Pepin took center stage during lunch. While Pepin was inside the building schmoozing with the likes of Dr. Jane Goodall, her trainers hid scat in a giant, wide open field area. Once the crowd gathered, Pepin was taken outside, given directions and once released, blasted with determination and blatant glee out into the field. Within 3 minutes she had located the scat and sat proudly next to it, indicating to her trainer that she had done her job; a job that would have taken a human hours.

Being able to find scat helps humans track down various species in the wild and provides needed species conservation information. Deployed conservation dogs have increased scat sample collection rates and have discovered samples that are smaller and more cryptic than people alone are capable of detecting. The working dogs for conservation have found scat of moose, snow leopard, grizzly bear, wolf and cougar, to name a few. The dogs have also been trained to find plants and lost pets and people.

Partnering with dogs is nothing new. Humans have been using the 220 million scent-sensitive cells available for canine olfaction for centuries. These animals are truly man's best friend, but perhaps they are becoming nature's best friend, as well. They certainly deserve to hold this most unusual job.

37.762611 -122.409719

Titan Arum, or Corpse Flower

This particular specimen was unfortunately not yet in bloom.  The Corpse Flower also known as the Titan Arum is best known for the smell it emits when in bloom.  It only blooms for 24 to 48 hours and it emits a smell that can range from rotting garbage to a dead corpse.  When I viewed it on Wednesday, the petals known as the spathe were wrapped around a very large hollow stem known as a spadix.  On the outside the spathe were green and you could just see the deep burgundy fray of the interior portion of the spathe.  The corpse flower not only emits a rotting meat fragrance when the spathe finally opens.  The flower's deep red or burgundy color and texture mimic the texture and appearance of rotting meat.  Moreover, during bloom the spadix heats up to the about 98 degrees Farenheit, which helps the perfume permeate the air and further seals the illusion of rotting meat.  All these attributes during bloom will then attract carrion-eating beetles and Flesh Flies that it turn pollinate the Corpse Flower in its native tropical forest clime in Sumatra.

After viewing the almost three foot Corpse flower personally, I have been following the daily blog about its progress on the Friend of the Greenhouse at  www.fotgh.com.  The blog has been updated faithfully by the Greenhouse Manager, Martin Marhoot.  Early last week the flower debunked experts by staying closed on the day they had predicted for it to open.  It is further being perplexing by given not a rancid odor but one quite sweet and familiar – that of chocolate!  This morning, which is Friday, July 3^rd as I write this, It started to emit this odor.  The spadix also increased in girth and it looks now like the spathes will relax and open just in time for fourth of July  What kind of scent will waft through Greenhouse is now up for debate.

37.72271054188601 -122.47676610946655

Love is in the air

We've known for awhile that animals find their "true love" partly through smells. One of the things they are sensing is whether the potential mate has a different set of MHC genes.

MHC genes are a big part of our immune system. These genes are used to create the huge number of antibodies that we each make to battle bacteria, viruses, etc. Everyone has a different set of these antibodies.

The more varied your MHC genes are, the more invaders your immune system can recognize and defeat. So two parents with very different MHC genes will have kids with immune systems that can recognize (and so defeat) lots of different kinds of bacteria and viruses. Parents with similar MHC genes will have kids with less varied immune systems. (This is a big reason why inbred animals are so sickly.)

Animals can tell about a potential mate's MHC genes through smell. And people might be able to do this as well.

Lots of experiments have been done where men or women sniff the sweaty t-shirts of members of the opposite sex to see which t-shirt smells better. If the potential mates are of the same ethnic group, the sniffers tend to prefer mates with very dissimilar MHC genes. If the potential mates were of different ethnic groups, the sniffers preferred mates with somewhat but not wildly dissimilar MHC genes.

The new study looked at a group of 30 European American couples from Utah and 30 Yoruba couples from Nigeria. Thankfully there was no sweat smelling involved. Instead the researchers compared the DNA between the spouses of each couple in many different places throughout their genome.

What they found was that for the Utah couples, the DNA around the MHC genes was much less alike than the DNA almost everywhere else. This did not appear to be the case for the Yoruba couples. This suggests that at least for these 30 couples from Utah, having a very different set of MHC genes may have been part of picking a spouse.

Why the difference between the Utahans and the Yorubans? It is hard to say without more data but one possibility has to do with how much of a role social factors play in picking a spouse in each society. Perhaps the European Americans are freer to choose a mate. If this is the case, then they might be more likely to follow some sort of biological imperative.

Another possibility is that this smell test is only a big deal if the potential mates are all very similar to start with. The Utah couples all had pretty similar DNA to each other to begin with. The Yoruba couples' DNA was less alike.

Of course, this is a total of 60 couples and so is in no way exhaustive and may be proven wrong tomorrow. But it adds to a growing pile of evidence that suggests how mate selection works at the biological level. And it shows the wide range of things we can learn about ourselves by studying our DNA in great detail. Maybe it even gives perfume companies some ideas too.

37.332 -121.903