We performed all-electron quantum chemical calculations based on the density functional method for des-pGlu brazzein, one of the sweetest protein, and six different mutants in order to examine a relationship between the sweetness of sweet-tasting proteins and their electronic properties such as electrostatic potential and frontier molecular orbitals, HOMO and LUMO. The calculated electrostatic potential maps for des-pGlu brazzein and two different sweet-tastting mutants showed that a number of amino acid residues including neutral amino acids, Tyr8 and Tyr51, have positive charge and especially for two mutants the positive charge widely spreads over each mutant. In addition, we found that some positively charged amino acid residues occur in the HOMO and/or LUMO of des-pGlu brazzein and two sweet-tasting mutants. A comparison of our computational results with experimental results on the sweetness of mutants suggests that the charged amino acid residues are involved in changing and/or eliciting the sweetness of des-pGlu brazzein. Our computations also indicate that the charged amino acid residues, the charge distribution and the property of HOMO and LUMO of sweettasting proteins can play important roles in the interaction between the proteins and the human receptor protein T1R2/T1R3.

An aroma is composed of many ingredients. Some key compounds possess very high-performance in spite of extremely small amount in the total aroma. Using them, the quality of the aroma could be surprisingly improved.

As such flavor ingredient, we found the high-performances of linear unsaturated aldehydes, (E)-6-nonenal, (E)-6-octenal, (Z)-8-pentadecenal and (4Z,7Z)-4,7-tridecadienal, and (6Z,8E,10E)-6,8,10-undecatrien-3-one which is a novel compound in Japanese citrus.

(E)-6-Nonenal, (E)-6-octenal, and (Z)-8-pentadecenal had the effect of enhancing the satisfaction when eating plant and animal oil and fat, which are expected as the useful flavor ingredients for low fat processed food.

(4Z,7Z)-4,7-Tridecadienal was an essential component for bonito flavor and had the effect of suppressing sourness.

(6Z,8E,10E)-6,8,10-Undecatrien-3-one was an very important ingredient to differentiate yuzu aroma from the other citrus. Furthermore, the chemical had the effect of enhancing sensation of carbonating.

The market of fabric softeners with long-lasting scents is expanding in recent years, and the softeners have driven the aroma booms of daily necessities. At present, the softeners are used not only to soften clothes but also to enjoy the scents, and “long-lasting favorite scent” is mainly required for young people. The preferred scent tones for softeners are fresh and flowery. The fragrance components that make up their scent tones are hydrophilic and volatile. Therefore, they were difficult to be adsorbed and to remain on the clothes even if they were blended in softeners. In order to solve such a problem, we focus on the fragrance-precursor which can improve adsorption and sustained release of the fragrance components. The fragrance-precursors also have the ability to create fresh and flowery scent responding to moisture, and they give to new values of aroma with the comfortable fluctuation scent.