可食性蛋白质酶水解过程中形成苦味原因的探讨

本文探讨了天然蛋白质水解过程中形成苦味的原因。     

Individual differences in perceived bitterness predict liking of sweeteners

Although recent molecular studies suggest that only one receptorand one signaling pathway are involved in the perception ofsweetness, this seems to contradict everyday experience thatpeople not only have different likes and dislikes of certainsweeteners but also perceive the sweeteners differently. Onepossible explanation is that variation in liking of sweetenersis due, in part, to variation across individuals in sensitivityto nonsweet tastes, such as bitterness, which are transducedby a variety of receptors. Fifty individuals were asked to rateintensities of several taste attributes of 10 sweeteners andto give hedonic assessments of each sweetener. Additionally,their sensitivity to 6-n-propyl-3-thiouracil (PROP) was determined.Results indicated that when matched for sweetness, the perceptionof bitterness and the sweetener compound were the 2 largestfactors contributing to overall liking of a sweetener. Sensitivityto PROP did not contribute significantly to the model.     

Design and Optimization of Mefloquine Hydrochloride Microparticles for Bitter Taste Masking

The objective of the present investigation was to reduce the bitterness with improved dissolution, in acidic medium (pH 1.2), of mefloquine hydrochloride (MFL). Microparticles were prepared by coacervation method using Eudragit E (EE) as polymer and sodium hydroxide as precipitant. A 3² full factorial design was used for optimization wherein the drug concentration (A) and polymer concentration (B) were selected as independent variables and the bitterness score, particle size and dissolution at various pH were selected as the dependent variables. The desirability function approach has been employed in order to find the best compromise between the different experimental responses. The model is further cross validated for bias. The optimized microparticles were characterized by FT-IR, DSC, XRPD and SEM. Bitterness score was evaluated by human gustatory sensation test. Multiple linear regression analysis revealed that the reduced bitterness of MFL can be obtained by controlling the dissolution of microparticles at pH 6.8 and increasing the EE concentration. The increase in polymer concentration leads to reduction in dissolution of microparticles at pH > 5 due to its insolubility. However the dissolution studies at pH 1.2 demonstrated enhanced dissolution of MFL from microparticles might be due to the high porosity of the microparticles, hydrophilic nature of the EE, and improved wettability, provided by the dissolved EE. The bitterness score of microparticles was decreased to zero compared to 3+ of pure ARM. In conclusion the bitterness of MFL was reduced with improved dissolution at acidic pH.     

Indinavir-Loaded pH-Sensitive Microparticles for Taste Masking: Toward Extemporaneous Pediatric Anti-HIV/AIDS Liquid Formulations with Improved Patient Compliance

The aim of this work was to develop indinavir pediatric anti-HIV/AIDS formulations enabling convenient dose adjustment, ease of oral administration, and improved organoleptic properties by means of the generation of drug-loaded microparticles made of a polymer that is insoluble under intake conditions and dissolves fast in the stomach in order to completely release the active agent. Indinavir-loaded microparticles made of a pH-dependent polymeric excipient soluble at pH < 5, Eudragit E100, were prepared using a double emulsion solvent diffusion technique and the in vitro release profiles characterized. Finally, taste masking properties were evaluated in blind randomized sensory experiments by ten healthy human volunteers. The use of a w/o/o emulsion system resulted in indinavir loads around 90%. Thermal analysis of the microparticles by differential scanning calorimetry revealed that indinavir appeared mainly dispersed at the molecular level. Concentrations of residual organic solvents as determined by gas chromatography were below the upper limits specified by the European Pharmacopeia for pharmaceutical oral formulations. Then, the behavior of drug-containing microparticles in aqueous media at different pH values was assessed. While they selectively dissolved in gastric-like medium, in tap water (intake conditions), the matrix remained almost unchanged and efficiently prevented drug dissolution. Finally, sensoring taste tests performed by volunteers indicated that systems with indinavir loads ∼15% displayed acceptable taste. This work explored the production of indinavir-containing microparticles based on a common pharmaceutical excipient as a means for the improvement of medicines of drugs involved in the treatment of HIV/AIDS. For systems containing about 15% drug, taste studies confirmed the acceptability of the formulation. In pediatric regimes, this composition would require an acceptable amount of formulation (0.7–1.5 g). Diego A. Chiappetta and ángel M. Carcaboso contributed equally to this work.     

乳蛋白质水解液脱苦方法研究

通过对乳蛋白质酶水解液的脱苦研究,结果表明:乳蛋白质在酶水解过程中,随着水解度的增加,苦味值增大;在水解度为66％时,苦味值最大;随后苦味值减小;3％粉末状活性碳对水解液的脱苦效果好。     

Tactile interaction with taste localization: influence of gustatory quality and intensity

Taste is always accompanied by tactile stimulation, but little is known about how touch interacts with taste. One exception is evidence that taste can be "referred" to nearby tactile stimulation. It was recently found (Lim J, and Green BG. 2007. The psychophysical relationship between bitter taste and burning sensation: evidence of qualitative similarity. Chem Senses. 32:31-39) that spatial discrimination of taste was poorer for bitterness than for other tastes when the perceived intensities were matched. We hypothesized that this difference may have been caused by greater referral of bitterness by touch. The present study tested this hypothesis by comparing localization of quinine sulfate and sucrose under conditions that minimized and maximized the opportunity for referral. In both conditions, stimulation was produced by 5 cotton swabs spaced 1 cm apart and arranged in an arc to enable simultaneous contact with the front edge of the tongue. Only one swab contained the taste stimulus, whereas the rest were saturated with deionized water. In both conditions, the swabs were stroked up-and-down against the tongue 5 times. Subjects were asked to identify which swab contained the taste stimulus 1) 5 s after the fifth stroke (touch-removed condition) and 2) immediately at the end of the fifth stroke, with the swabs still in contact with the tongue (touch-maintained condition). Ratings of taste intensity were obtained to assess the possible effect of perceived intensity on spatial localization. Taste localization was surprisingly accurate, especially for sucrose, with errors of localization in the range of 1 cm or less. For both stimuli, localization tended to be poorer when the tactile stimulus was present while subjects made their judgments, but the difference between conditions was significant only for the lower concentration of quinine. The results are discussed in terms of both the surprisingly good spatial acuity of taste and the possibility of having a close perceptual relationship between touch and bitter taste.     

Human Bitter Taste Receptors hTAS2R8 and hTAS2R39 with Differential Functions to Recognize Bitter Peptides

The strong bitter peptide, Phe-Phe-Pro-Arg, activated cultured cells expressing either of the known human bitter taste receptors, hTAS2R8 and hTAS2R39. The partial structure of Pro-Arg activated hTAS2R39, but did not activate hTAS2R8. These receptors may not indiscriminately recognize bitter peptides, but have a differential function in their recognition.     

大枣对杜仲风味修饰与功效增强作用的研究

通过大枣与杜仲配伍的研究,发现大枣对杜仲有风味修饰和增强杜仲功效的作用,两者配伍后,不仅具有杜仲补肝肾的功能,还具有大枣补脾胃的作用,达到了既补肝肾、又调脾胃的特异效果。     

The psychophysical relationship between bitter taste and burning sensation: evidence of qualitative similarity

Although it has long been studied as a pure sensory irritant, the ability of capsaicin to evoke, mask, and desensitize bitter taste suggests that burning sensations and bitter taste might be closely related perceptually. The current study investigated the psychophysical relationship between bitterness and burning using 2 different approaches. In Experiment 1, spatial discrimination of 4 taste stimuli was measured in the presence or absence of capsaicin. The subjects' task was to report which of 3 swabs, spaced 1 cm apart and presented to the tongue tip, contained a taste stimulus when 1) water was presented on the other 2 swabs or 2) when 10 muM capsaicin was presented on all 3 swabs. The presence of capsaicin did not change performance on the 3 alternative forced-choice (3-AFC) task for sweet, sour, and salty stimuli, while the localization error for 1.8 mM quinine sulfate (QSO(4)) increased significantly. In Experiment 2, the perceptual similarity/dissimilarity of taste stimuli and capsaicin was measured directly using pairs of stimuli applied to opposite sides of the tongue tip on swabs separated by 2 cm. Multidimensional scaling analyses showed that capsaicin fell nearer to QSO(4) than to any other taste stimulus. Cluster analysis corroborated this finding: capsaicin was closely linked with QSO(4) and the capsaicin-QSO(4) group was separated from the other taste stimuli. The latter result indicated that bitterness was more similar to burning than to the other tastes. These findings imply that despite being mediated by different sensory modalities, bitterness and burn are qualitatively similar. We speculate that this similarity reflects a common function of these 2 sensations as sensory signals of potentially harmful stimuli.