Products made from Herba Santa (Eriodictyon californicum (H. & A.) Torr.) have been used as bitter remedies for some pharmaceutical applications for many years, but they are actually too aromatic to be useful for many food or pharmaceutical applications. In sensory studies flavanones homoeriodictyol (1), its sodium salt (1-Na), sterubin (2), and eriodictyol (4) could significantly decrease the bitter taste of caffeine without exhibiting intrinsic strong flavors or taste characteristics. Further investigations on 1-Na elicited a broad masking activity between 10 and 40% toward different chemical classes of bitter molecules (e.g. salicin, amarogentin, paracetamol, quinine) but not toward bitter linoleic acid emulsions. For caffeine and amarogentin, dose-response studies were performed; the masking activity toward bitter taste for both compounds reached a plateau at higher concentrations of 1-Na. Due to these facts, homoeriodictyol sodium salt (1-Na) seems to be a very interesting new taste modifier for food applications and pharmaceuticals.

Some microorganisms can transform methyl ricinoleate into ␥-decalactone, a valuable aroma compound, but yields of the bioconversion are low due to (i) incomplete conversion of ricinoleate (C 18 ) to the C 10 precursor of ␥-decalactone, (ii) accumulation of other lactones (3-hydroxy-␥-decalactone and 2-and 3-decen-4-olide), and (iii) ␥-decalactone reconsumption. We evaluated acyl coenzyme A (acyl-CoA) oxidase activity (encoded by the POX1 through POX5 genes) in Yarrowia lipolytica in lactone accumulation and ␥-decalactone reconsumption in POX mutants. Mutants with no acyl-CoA oxidase activity could not reconsume ␥-decalactone, and mutants with a disruption of pox3, which encodes the short-chain acyl-CoA oxidase, reconsumed it more slowly. 3-Hydroxy-␥-decalactone accumulation during transformation of methyl ricinoleate suggests that, in wild-type strains, ␤-oxidation is controlled by 3-hydroxyacyl-CoA dehydrogenase. In mutants with low acyl-CoA oxidase activity, however, the acyl-CoA oxidase controls the ␤-oxidation flux. We also identified mutant strains that produced 26 times more ␥-decalactone than the wild-type parents.

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