ADVERTISEMENT FEATURESPOTLIGHT ON FOOD SCIENCE IN JAPANRYUKOKU UNIVERSITY

Exploringthe boundaries of taste
Bringing together renowned chefs
from Japan’s culinary heartland
and world-leading scientists in foodpalatability, Ryukoku University’s
new Center for Research on Food
Palatability is unravelling the mystery of taste to establish the scienceof palatability and push the frontiersof Japanese cuisine.

O

ne of Japan’s oldest cities andthe imperial residence for overa millennium, Kyoto boasts aremarkable depth of tradition and historical continuity that have defined Japaneseculture since the eighth century. Backthen, as today, cuisine and its mastery areintegral to the culture and hallmarks of theJapanese approach to both food and life.
Now, Ryukoku University, one of Japan’s
oldest educational institutions, is taking
mastery of the sensory experience of cuisine even further with the country’s firstCenter for Research on Food Palatability.
“Our new centre brings together chefs
from renowned Kyoto restaurants and scientists at the forefront of taste research tofurther our knowledge of palatability andAdvertiser retains sole responsibility for content

conduct innovative research on Japanesecuisine,” says centre director Tohru
Fushiki. “We also collaborate with product development researchers from theprivate sector to tackle problems andchallenges specific to these partner corporations. With over 370 years of history
in the renowned culinary centre of Kyoto,
Ryukoku University is ideally placed tomake a global impact in this new interdisciplinary and practical research field.”
A food scientist and nutritionist, Fushiki
has been studying the detailed mechanics of what makes food palatable for overa decade. From the isolation of taste
bud receptors responsible for differenttastes, to the olfactory and stimulatory
mechanisms in the brain that reward us
with feelings of satisfaction and joy inresponse to pleasing tastes, palatability isa complex and strongly interdisciplinary
mystery that Fushiki and his colleagues
are intent on deciphering.
Fats and palatability
Increasing the fat and oil content of foodis known to make a product tastier andmore satisfying, but the physiological andneurological mechanisms responsible are
only just beginning to be revealed. As ingested fats and oils are broken down andabsorbed in the gastrointestinal tract, opioids are generated in neurons of the hypothalamus region of the brain — the brain’s
reward system. In this way, the ingestionof fat results in addictive, reward-seeking
behaviour, but the mechanism linking thegut and brain remains unknown.
“Pure fats and oils cannot be discernedby the human senses of taste or smell,
but when combined with other ingredients, high-fat foods are perceived as
delicious,” says Fushiki. “In other words,

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highly concentrated fats and oils stimulate the brain’s reward system, which inturn amplifies the flavours in food andsignificantly enhances palatability.”
Interestingly, energy-free fat substitutes do not stimulate the same reward
system via the gut in this way. Yet recent
findings by Fushiki’s team suggest that
there may be other routes to achieve fatdriven palatability.
“Fatty acids and volatile compounds
released by cooking and ageing have a
distinctive aroma, which is a key component of the palatability of fats andoils since it signals their presence via
olfaction,” explains Fushiki. “Our olfactory memories are very stable over long
periods and help us recognize food andassess its relative palatability. So by replacing fats and oils with small amountsof fatty acids, it is possible to create foods
that have low calorie contents but are still
highly palatable. It is discoveries such asthese that will become increasingly important for the food industry as it strives
to improve palatability while reducing fatand sugar content.”
The umami effect
Sweetness, saltiness, acidity and bitterness have long been known as primary
tastes for which humans have specificreceptors. It was not until the 1980s thata fifth primary taste, known as umami,
was named and generally recognizedby the scientific community, although it
was first scientifically identified in Japan
almost a century earlier. Umami is discerned by taste receptors that are specifically stimulated by glutamate — anamino acid found in savoury meat broths
and fermented products and the basis
for the taste-enhancing effect of monosodium glutamate (MSG). Traditional
Japanese cuisine relies heavily on umami in the form of broths prepared using
cured bonito fish and kombu seaweed,from which MSG was originally isolated.
In fact, this prominence of umami gives
Japanese food its distinctive palatability
and broad global appeal.
“We discovered that the same mechanism by which fats, oils and sugars stimulate the brain’s reward system is alsopresent for umami-rich Japanese broth,”

SPOTLIGHT ON FOOD SCIENCE IN JAPANsays Fushiki. “This means that there isa biological preference for the taste ofumami, and that the traditional Japaneseumami taste can provide the same senseof fullness and satisfaction that sweet andhigh-fat foods do in Western diets. This
explains why traditional Japanese cuisine
has relatively low calorie and fat content
but remains highly palatable. Becauseof this, Japanese food can make a positive contribution to the health of people
around the world.”
Quantifying good taste
A major theme of research at the Centerfor Research on Food Palatability is thedevelopment of methods to quantify thesubjective evaluation of taste. As taste
preferences vary among individuals, it isdifficult to achieve an objective understanding of palatability. The recognition
that many aspects of ‘deliciousness’
reside not with the foodstuff but with theindividual has made it possible to achievesome important advances in this area.
“We have demonstrated that palatability can be expressed in terms of four main
factors: physiological palatability or thesensation of deliciousness; food culture
as shaped by social customs; information
on safety and desirability; and the brain’s
addictive reward system,” says Fushiki.
While physiological and brain reward system factors are shared to asignificant extent by all humans, cultural and information-related factors arestrongly influenced by individual experience and background.
“Based on these factors, we have created a list of questions to assess thepalatability evaluations that people
consciously and subconsciously makewhen consuming food. The ability toeven roughly measure such a subjective
evaluation of the relative deliciousness ofa food allows for further improvements inthe development of new food products.”

Exploring the frontiers of Japanesecuisine
Through the Center for Research on Food
Palatability, a group of scientists andrenowned chefs from well-establishedJapanese restaurants in Kyoto has been
conducting experiments aimed at finding possibilities for innovation in traditional Japanese cuisine. Using a speciallyequipped meeting kitchen at Ryukoku
University, these culinary experiments
explore specific themes over the courseof six months or more. The Boundaries of
Kyoto Cuisine is a recent example of sucha research project, which considered how
to simultaneously protect Japanese foodculture and engage with globalization.
“We presented the results of our research at a recent public symposium,”says Fushiki. “Our audience included
professional chefs, people working in thecorporate food industry and local government officials. Collaboration with product development researchers from theprivate sector is a particularly important
aspect of our new centre.”Through this cross-disciplinary interaction, the centre has established aplatform for developing innovative ideas
for novel kinds of cuisine, as well as new
culinary techniques for use in traditional
cuisine. “We hope our research will help
the Japanese food product industry
better meet the needs of the elderly,
hospital patients, school lunch programmes and people seeking to restrict
their calorie intake by providing food
options that are healthful and delicious,”says Fushiki. “To enhance the qualityof life of Japanese citizens, safeguard
Japanese food culture and contribute to
the development of food products thatmeet contemporary consumer needs,
we need a sophisticated and precise understanding of palatability ― that’s themission of the Center for Research on
Food Palatability.”

Contact

E-mail:r-globe@ad.ryukoku.ac.jp
Tel: 	+81 (0) 75 645 7898
Fax: 	+81 (0) 75 645 2020
Website:www.ryukoku.ac.jp/english2/cfp/
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