食品機能と感性の科学

　　主として食品素材の化学的特性、生理機能を生物有機化学的に解明することにより、食品成分の品質形成とその機能性の保持を図ること及び食品成分の人間の感覚･健康に与える影響を明らかにすることを目的に、研究を行っている。現在の研究課題を大別すると次のようになる。

１. 食品成分の生理機能解析

(１).食用植物成分ポリフェノールの化学と機能性

食品と視覚的に関わるアントシアニン色素の食品成分としての有効利用を目的とする。色素の色調の安定性の研究、生理機能（抗酸化性、生理的に重要な酵素活性との相互作用など）の研究、植物組織培養による人工的な生産、その生産制御、色素成分の植物中での動態追跡など幅広く検討を行い、おもに植物二次代謝産物と健康との関わりを重要なテーマとしている。アントシアニン色素の機能性に関する研究では、現在赤ワインの中のポリフェノール成分が血中コレステロール量を減少させることが明らかになり、世界中で活発に議論されている。我々もこの問題をアントシアニン色素の抗酸化活性の点から検討し、アントシアニンの効果をいち早く報告した。今後も色素の未知機能性の開発を続ける。

(２).抗ウイルス活性

われわれ人類はさまざまなウイルスからの攻撃に曝されている。免疫力、抵抗性を高める食品あるいは食品成分を明らかにし、予防する方策につながる研究を検討している。レタス培養細胞の生産するトリカフェオイルキナ酸の抗ウイルス活性を報告した。

(３).抗発ガンプロモーター活性成分

四国各地に栽培されている食品素材から抗発ガンプロモーター活性成分の検索についても検討中である。当大学の近藤により開発されたRaji細胞というBリンパ細胞の変形抑制試験を用い、さまざまな機能成分が単離されている。

(４) 抗アレルギー活性成分

天然に存在する食材に含有される成分の抗アレルギー活性をRBL－2H3細胞を用いた試験によって調べている。天然物由来の成分に抗アレルギー活性が見つかれば、普段の食事や抗アレルギー剤により、副作用を伴わず、アレルギー症状を抑制できると考えている。

２. 超分子複合体形成能によるポリフェノールの単離法

超分子は共有結合に依らない弱い分子間の静電的相互作用に基づき分子会合をする。この超分子の自己組織化を利用し、機能性食品素材であるアントシアニンの簡便な単離法の開発のための基礎的検討を行っている。

3. においの特性解析

(１). 食品の揮発成分分析法

揮発成分は微量であり、食品香気はこのような揮発成分が多成分集まり構成されている。一般に一つの食品で、揮発成分は２００成分以上存在するものが多い。この香り成分の混合により、さまざまな特徴的なにおいが創造されている。微量で有用な成分探索は食品、化粧品などさまざまな利用面での応用が期待されている。

(２). 官能特性の評価法の検討

本研究室のメインテーマの一つ。匂いの感覚刺激を与えている物質、特にその食品の姿を連想する作用のある成分はどのような物質なのか、２００種以上ある食品のにおい成分からその成分を見つけ出す手法を築き上げている。Lod法、オーダーインパクトスペクトラムの開発や刺激の大きさを客観的尺度で評価する方法など評価系を開発中である。

(３). かおりの機能特性

揮発成分に対する生物の応答、アメニティー、生物間情報伝達物質、さらに医療（アロマ療法）など広く発展している。無意識下の効果はにおいにもあると考える。食品の匂い成分が与える心理的、生理的影響はどの程度なのか、その効果を測る基盤を築いている。これまでに、においと脳波の関係などを検討してきた。

Food Science of food function and interaction of food components with human receptors

We intend to maintain the quality and the functionality of food
ingredients as well as to clarify the effect on human’s health by elucidating the chemical characteristics and physiological functions of food material at the bio-organic chemistry level. Our current research can be clasified into 3 parts.

https://www.researchgate.net/profile/Hirotoshi_Tamura?ev=hdr_xprf

1. Analysis of the physiological functions of a food ingredient.

(1) Chemistry and functionality of polyphenol from edible plant extracts.

We study on the stability of anthocyanin, physiological function (such as anti-oxidant activity, interaction between important enzymes and anthocyanin), artificial productivity by plant tissue culture and production control, traceability of antocyanin in organisms.
In the research on the functionality of anthocyanin pigments, it has become clearer that the polyphenol ingredient in red wine reduces the amount of cholesterol present in the blood, which has been discussed widely. We had been examining the antioxidant activity of anthocyanin pigments, also have reported about the effect of anthocyanin. In the future we intend to continue developing functionalities of the anthocyanin pigment.

1. Tamura, H., Kitta, K. and Shibamoto, T.: Formation of reactive aldehydes from fatty acids in a Fe2+/H2O2 oxidation system. Journal of Agricultural and Food Chemistry 39, 439-442 (1991).
2. Tamura, H., Yamagami, A.: Antioxidative activity of monoacylated anthocyanins isolated from Muscat Bailey A grape, Journal of Agricultural and Food Chemistry 42 (8), 1612-1615 (1994).
3. Poudel, PR., Tamura, H., Kataoka, I. and Mochioka, R.: The antioxidant activities of skins and seeds of five wild grapes and two hybrids native to Japan. J. Food Compositional Anal. 21(8), 622-625 (2008).

(2)Anti-viral activity
Human beings are exposed to attacking from various viruses. Our study is about foods or food ingredients that can enhance immunity and resistance, to which relating to the measures that can prevent virus infection. According to our past research, tri-caffeoylquinic acid from lettuce cells has antiviral activity.

(3) Anti-cancer promoter active ingredient
We are also examining about an anti-cancer promoter active ingredients from food ingredients which are grown all over the island of Shikoku. Using inhibition test by Raji cell (a variant of B-cell lymphoma) that has been developed by the University's Kondo, various functional components are being found.

1. Dalad Siriwan, Takayuki Naruse, and Hirotoshi Tamura, Effect of epoxides and a-methylene-g-lactone skeleton of sesquiterpenes from yacon (Smallanthus sonchifolius) leaves on caspase-dependent apoptosis and NF-kB inhibition in human cervical cancer cells. Fitoterapia, 1093-1101 (2011)
2. Dalad SIRIWAN, Chika MIYAWAKI, Takeo MIYAMOTO, Takayuki NARUSE, Katsu-ichiro OKAZAKI and Hirotoshi TAMURA, Anti-tumor promoting and cytotoxic activities of sesquiterpene lactones (SLs) isolated from Smallanthus sonchifolius (yacon) leaves. Pakistan Journal of Biological Science, 14 (10), 605-609 (2011)
3. Piyapat Trisonthi, Kana Miyagawa and Hirotoshi Tamura, Induction of Apoptosis in HeLa cells by Methanolic Extract of Litsea cubeba Fruit Residue from Essential Oil Extraction, J. Life Sciences, 7 (9), 928-934 (2013).

(4)Anti-allergic active ingredient
Anti-allergic activity of the components contained in the natural food material is being investigated by using RBL-2H3 cell. If the components that possess anti-allergic activity derived from natural products have been found, allergic symptoms can be inhibited without side effects by usual food and anti-allergic agent.

1. Surojanametakul V., Doi H., Shibata H., Mizumura T., Takahashi T., Varanyanond W., Wannapinpong S., Shoji M., Ito T., and Tamura H. Reliable Enzyme-Linked Immunosorbent Assay for the Determination of Coconut Milk Proteins in Processed Foods, J. Agric. Food Chem., 2011, 59 (6), 2131–2136
2. Akihiko Sato, Atsushi Yamagami and Hirotoshi Tamura, Suppression of degranulation of RBL 2H3 cells by means of flavonoids in natural plants. Chiang Mai University Journal of Natural Sciences, 11 (1), 343-349 (2012).

2.Isolate method of polyphenols by the ability to form supramolecular complexes

Supramolecular is linked by weak non covalent bond such as electrostatic interactions. Use of supramolecular self-assembled, we are doing a fundamental study for the development of a simple isolation method of anthocyanin which is a functional food material.

1. Takayuki Asada and Hirotoshi Tamura, Isolation of Bilberry anthocyanins 3-glycosides bearing ortho-dihydroxy groups on the B ring by forming aluminium complex and their antioxidant activity, J. Agric. Food Chem., 60(42), 10634-10640 (2012).
2. Fengxian Zhu, Takayuki Asada, Akihiko Sato, Yoriko Koi, Hisashi Nishiwaki, and Hirotoshi Tamura, Rosmarinic Acid Extract for Antioxidant, Antiallergic and α-Glucosidase Inhibitory Activities, Isolated by Supramolecular Technique and Solvent Extraction from Perilla Leaves, J. Agric. Food Chem., 62(4), 885-892 (2014).

3. Characterization of odor

(1) Analysis of food volatile component
Food flavor consists of variety of volatile components which are in small quantity. Usually, one kind of food contains more than 200 volatile components. By mixing these aroma components together will make a distinctive smell. The effective of a small amount of these components are expected to be applied to food and cosmetics fields.

1. Boonbumrung, S., Tamura, H., Mookdasanit, J., Nakamoto, H., Ishihara, M., Yoshizawa, T. and Varanyanond,W.: Characteristic aroma components of the volatile oil of yellow keaw mango fruits determined by limited odor unit method. Food Science and Technology Research 7(3), 200-206 (2001).
2. Mookdasanit, J. and Tamura, H., Yoshizawa, T., Tokunaga, T. and Nakanishi, K.: Trace volatile components in essential oil of Citrus sudachi by means of modified solvent extraction method. Food Science and Technology Research, 9 (1), 54-61 (2003).

　(2) Study on evaluation of sensory properties
This is one of the main topics in our laboratory. We intent to find out the substances that stimulate the sense of smell, especially certain components have associative effect of the figure of that particular food. So we are building up a method to clarify these components from more than 200 species of odor components of food. Evaluation system is being developed, including how to evaluate the magnitude of the stimulation objectively, Lod and order impact spectrum.

1. Chida, M., Yamashita, K., Izumiya, U., Watanabe, K. and Tamura, H.: Aroma Impact Compounds in Three Citrus Oils: Cross-Matching Test and Correspondence Analysis Approach. Journal of Food Science, 71, S54-58 (2006).
2. Tamura H., Hata Y., Chida M. and Yamashita K.: Picking aroma character compounds in Citrus limon oils by using odor thresholds in aroma mixtures: Food Flavor: Chemistry, Sensory Evaluation and Biological Activity (Tamura H. et al. eds), ACS Symposium Series, 988, 229-242 Washington DC, American Chemical Society (2008).

　(3) Functional properties of the fragrance
Biological response against the volatile components, amenities, materials of information transfer between biological, medical care (aroma therapy) have been developed extensively. Smell is also effective under unconscious. We have been made foundation to measure psychological, physiological effects of food odor components. So far, we have investigated the relationship between smell and electroencephalogram.

1. Kano S., Maeyama K., Wang Y., Kondo A., Furomoto T. Fukui H. and Tamura H. Suppression of the deformation of Raji cells by (E)-2-alkenals aroma compounds of coriander (Coriandrum sativum L.) leaves and behavior of (E)-2-dodecenal in rat blood. “Nutrition, Functional and Sensory Properties of Foods”. Chi-Tang Ho, Cynthia Mussinan, Fereidoon Shahidi, Ellene Tratras Contis (Edited) (2013), RSC publishing, Cambridge, UK, pp 313-323