[in Japanese]

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Recently, the number of complaints of off-flavors in foods has increased. Consumers are more sensitive to food, because many problems which threaten the food safety has happened in the past decade. Firstly, people feel off-flavor if they considered it different from their experiences or expectations.
On the other hand, the off-flavors occur from abnormal products - e.g. food rot, inappropriate composition of ingredients and conditions, using the package contaminated with volatile compounds, during processing - and chemical contaminants from outside - e.g. foreign materials in food, trapping volatile compounds from circumstance.
If off-flavor problem happened, the first step the food businesses must to do is quick response to the customer’s questions as soon as possible, and the second step is improving the product referring to the incidence. Therefore, the food businesses must keep and check the records of productions and complaints of the product, and investigate the source of the off-flavor by sensory testing and instrumental analysis.
This report introduces the off-flavor cases of the CO-OP brand product (private brand of Japanese Consumers’ Co-operative Union). As a matter of course, we have to assure the quality of products as a food supplier. In addition, we should make effort to provide the detail characteristic information of each food products, continuously. Especially in case of off-flavor, providing the information is very important because perception of flavors depend on each person to person.

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Recently, during 2007 to 2008, the serious incidents occurred in food industry in Japan, which shook entire food enterprises. In 2007, one of the major confectionary supplier falsified information on their products by using expired ingredients. In other incident, a meat processing company, another well-known confectionary manufacturer, and well- established traditional Japanese sweets producer used wrong labels information on their products. Further, in 2008 a restricted pesticide was detected in dumplings, which were supplied by Chinese food manufacture company. A world known incident of melamin contaminated infant milk was happened, which led a serious crisis in the reliability of the Chinese food industries. In Japan, the molded rice were distributed in the retail stores and the insect smell were absorbed into some instant foods, etc. The aforementioned news is well covered by media to grow consumer interest concerning the food safety, resulting in the substantial claims from end-users. Particular complains received are the odor and/or foreign materials. We present a suitable procedure to examine such odors together with analytical evidence of specimens prepared on the based on published information.

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Storing sake for a certain period causes deterioration of its aroma. This stale aroma is called “hineka”. It is considered that hineka is consists of many kinds of volatile compound. In general, hineka is regarded as an off-flavor formed during storage and commercial distribution, although it is a characteristic aroma of aged sake stored for a long period. We demonstrated that dimethyl trisulfide (DMTS) is one of the main components of hineka appeared in the general commercial sake. To elucidate the formation mechanism of DMTS, we investigated the precursor compounds of DMTS in sake and identified one of the precursors, DMTS-P1, as 1,2-dihydroxy-5-(methylsulfinyl)pentan-3-one.

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A novel cream was developed by combining membrane concentration and deoxygenation of raw milk prior to pasteurization. The cream was characterized by its unprecedented strong milk flavor and clear aftertaste. The cream was found to suppress the generation of unpleasant odor of heated egg. The cream was increased with the compositions related to milk aroma and taste. The oxygen removal prior to pasteurization was thought to suppress the oxidation of odor related compounds, resulting in the clear aftertaste. The suppression of unpleasant odor from food ingredients such as egg might be in relation to the deoxidized pasteurization, however, the mechanism is yet to be elucidated.

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Food adaptation by our consumption is mainly based on the flavor and quality of the product, especially, the flavor is affected by degradation due to lipid oxidation during storage. It is quite difficult to analyze the accurate aroma and orders of the food flavor because of the difficulty in selections suitable method for the extraction and analyses of the flavors.
In this report, therefore, as a useful method, the solid phase micro extraction (SPME) and recently developed flavor sensory instrument were introduced, and the basic mechanism of auto oxidation of unsaturated lipids was also summarized. Furthermore, the mechanism using antioxidants was also explained, and several flavor compounds of marine products by the SPME analyses were introduced. Finally, food safety for lipid processed foods, as an example, the lipid oxidation in noodle was examined for the safety level of lipid oxidation using the peroxide value based on the committee evaluation at Codex.

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Suppose that novel element is joined into existing odor category by a certain odorizer, consumers are expected to evaluate unconsciously goodness-of-fit for new one to that category. In this study, we utilized odor category of city gas as experimental material. And we tried to measure how participants evaluated goodness-of-fit for odor qualities to odor category of city gas. Participants, more specifically, were instructed to evaluate unacceptability for the original odor quality and four new ones of city gas, against specified verbal label, “city gas odor”.
We found that thirty participants were clearly classified into two groups based on evaluating unacceptability for new odor qualities against verbal label. One group (neophobia group) evaluated original odor quality of city gas as significantly lower unacceptability than four new ones. The other group (neophilia group), by contrast, showed rather comparable unacceptability among original odor quality and some new ones. In addition, neophobia group evaluated original odor as same unacceptability as neophilia one. We measured, moreover, odor quality-relevance between original odor quality of city gas and eighty-eight adjective-pairs as mental workload which was concerned to construct each semantic differential scale. Results demonstrated difference in mental workload for construction of these scales between two groups.

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We focused on the humidity control material as a means to control indoor cooking odors. For the purpose of understanding the deodorization efficiency of the building material, we measured the removal effect of ammonia by the small sample. And we measured cooking odors of the room (3640mm×7280mm×2500mm) where the humidity control material was used on the ceiling or the wall for 6 hours. The measurement items were odor concentration, odor quality, odor sensor vale, room temperature and humidity.
The odor concentration and odor sensor value in the room with the humidity control material on the ceiling were low compared with the value of the room with the humidity control material on the wall. The deodorization efficiency was demanded by the reduction rate of odor concentration of cooking end in the room with the humidity control material on the ceiling for the condition without the range hood, and the value was 69%. The humidity control material was quite effective for the removal of remained odor in the room.

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