Page 35 - FoodFocusThailand No.163 October 2019

SPECIAL INTERVIEW

Flavor (Aroma & Taste) Chemistry

Understanding Food Flavors to Create Desirable Foods

for Your Customers

Food consumption trend is changing rapidly towards healthy and sustainable
food. In the global level, consumers are highlighting quality raw materials as the
key purchasing factor alongside minimal processing in order to get the freshest
and the most authentic food possible.

For food producers, retaining authentic flavor and freshness can preventing the off-flavor formation.
be challenging. In food manufacturing, safety procedures such as Dr.Martin further stated that the European consumers tend to avoid
washing and thermal processing are normally applied. These food fortified with flavors, especially fruit juice. Therefore, fresh fruit flavor
procedures can alter the flavor of food, and consequently affect the is the Gold Standard. However, in the production of fruit juice, there are
quality of finished products. several processing steps involved which can alter the flavor of the fruit
On 10-11 July, 2019 the “Aroma Chemistry” seminar was held by juice. It is necessary to identify which processing step significantly alter
the Faculty of Science, Chulalongkorn University. Professor the flavor of the product and improve that processing step. Dr.Martin gave
Dr.Suwimon Keeratipibul cordially invited Dr.Martin Steinhaus, Food an example of his research on pineapple juice production. Fresh pineapple
Chemistry Researcher who is the Aroma Chemistry Specialist from juice and thermally processed pineapple juice have significantly difference
Leibniz-Institute for Food Systems Biology at the Technical University in flavor. He identified the key odorant in fresh pineapple, product after
of Munich (TUM) to deliver knowledge and experience on Aroma heat treatment to kill the microorganisms and final product (processed
Chemistry for Thai food manufacturers, researchers and academic fruit juice). It was observed there was significant difference in the
staffs. Food Focus Thailand magazine had the opportunity to interview concentration of methional in fresh and finished (processed) pineapple
Dr.Martin on this special issue as follow: juice. Actually, methional is presented in fresh pineapple but in the
Dr.Martin stated that consumers are more selective when choosing concentration below its odor threshold. This is why we do not perceive
food, and flavor is the main deciding factor to buy any food, regardless it. During the heating process, methional was formed and the final product
of its healthy or sustainability qualities. contained methional in the concentration more than 100 times above the
Flavor is a combination of taste and aroma. Many times, people odor threshold. It gives cooked flavor like cooked potato which is
are more focused on the taste of the actual food inside our mouth. unpleasant flavor in pineapple juice. Methional is formed during thermal
However, the aroma is more important when it comes to the fascination degradation of methionine. Therefore, thermal process should be
from consuming the food. Delicious food offers alluring aromas beyond improved or using non-thermal process such as high pressure processing
tastes that we can get from our tongues. The aroma from food is instead.
occurred from the smell of food before we consume (Orthonasal Odor Another example was a research on off-flavor of white pepper. In the
Perception), and the reflection of the smells in our nasal cavity after production of white pepper, producers soaked the black peppers in water
the food is swallowed (Retronasal Odor Perception). then fermentation process occurred. Fecal flavor was produced by
Our studies focus on identification of the chemicals responsible microorganisms during fermentation process and caused off-flavor in
for what we perceive from food that we consume. Our field of research white pepper. Therefore, changing soaking water frequently or changing
is called “Molecular Sensory Science”. We found that any kind of food to mechanical process was suggested.
materials contain a number of key aroma compounds which are not Professor Dr.Suwimon also said that the ability to identify the key
many, typically 10-20 compounds. Therefore, there are 2 steps of flavor compounds will lead to the changes in the upstream production
study; such as selection of planting areas and control of planting factors such
• Identification of the key aroma compounds (Food Chemistry side) as fertilizers, etc. to ensure that the produce contains the chemical
• Once we know the compounds, we will use them as a tool to compounds according to the food manufacturer requirements.
optimize the sensory properties of the food by adjusting the processing Professor Dr.Suwimon noted that Thailand is a prominent food
parameter to obtain the desire aroma of the processed food. (Food producer and food exporter of the world, with the main import markets
Technology side) based in Europe, USA and Japan. The optimization of flavor in food
It could be a misunderstanding for many people that food aroma products to upgrade aroma and taste will answer to the delicate demands
is caused by volatile substances. Therefore, they use Gas of consumers in these prominent markets and will add value and
Chromatography (GC) to detect the profile of volatile compounds. By competitiveness to Thai foods.
using GC, hundreds of volatile compounds can be detected. However, “In Thailand, Food Chemistry, especially Flavor Chemistry is a science
most of these compounds do not contribute to aroma in food. The key that needs further exploration in order to enhance value and
odorants/aroma compounds are small number and present in food in competitiveness of Thai foods in major markets. Integration of basic
a very small amount but above the threshold. Therefore, these key science knowledge such as chemistry, biochemistry to develop a solid
odorants contribute the aroma characteristic of the food. foundation for food industry which is one of the major industries of the
Therefore, to identify the key odorants we use human nose as the country is crucial”, said Professor Dr.Suwimon.
detector. By installing the Olfactometer at the sniffing port together Professor Dr.Suwimon also emphasized that research in flavor
with the Flame Ionization Detector (FID), the volatile compounds chemistry requires multidisciplinary personnel and massive funding.
separated by GC can be detected at both detectors at the same time Inevitably, support from the government is necessary. In Germany and
(Figure 1). By this method, volatile compounds which contribute aroma Japan, large companies established their own research unit on food flavor
can be elucidated as shown in graph on the right-hand side of the while the small and medium enterprises still need budget from the
Figure 1. government to hire the universities and research institutes to conduct the
From the graph, you can see that there are many peaks of volatile researches on food flavor.
compounds (Red Lines), but there are not many aroma compounds Dr.Martin finally stated that the collaborative researches on key
and they are presented in a small amount (Green Letters). odorants of Thai food ingredients including Thai fruits now are in progress.
There are several steps of research methodology to identify the Students were sent to Leibniz-Institute for Food Systems Biology at the
key odorants/aroma compounds which we call “Sensomic Approach”. Technical University of Munich (TUM) to learn the flavor research
Details of each step are in the handout distributed in the seminar. methodology several times. Research equipment and special glassware
The ability to identify the key odorants is useful for the application have already purchased and installed. Professor Dr.Suwimon and team
of quality control of raw materials (aroma aspect), change of aroma now have good understanding of flavor chemistry. Any difficulties such
during post harvesting, processing and storage. It could be useful for as chemical structure elucidation will be supported by Dr.Martin’s team.
both maintaining and enhancing the desired aroma as well as OCT 2019 FOOD FOCUS THAILAND 35

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