Taste Modification Research Articles

Electrophysiological studies of salty taste modification by organic acids in the labellar taste cell of the blowfly.

Using the labellar salt receptor cells of the blowfly, Phormia regina, we electrophysiologically showed that the response to NaCl and KCl aqueous solutions was enhanced and depressed by acetic, succinic and citric acids. The organic acid concentrations at which the most enhanced salt response (MESR) was obtained were found to be different: 0.05-1 mM citric acid, 0.5-2 mM succinic acid and 5-50 mM acetic acid. Moreover, the degree of the salt response was not always dependent on the pH values of the stimulating solutions. The salt response was also enhanced by HCl (pH 3.5-3.0) only when the NaCl concentration was greater than the threshold, indicating that the salty taste would be enhanced by the comparatively lower concentrations of hydrogen ions. Another explanation for the enhancement is that the salty taste may also be enhanced by undissociated molecules of the organic acids, because the MESRs were obtained at the pH values lower than the pKa(1) or pKa(2) values of these organic acids. On the other hand, the salty taste could be depressed by both the lower pH range (pH 2.5-2.0) and the dissociated organic anions from organic acid molecules with at least two carboxyl groups.

食品への膜の応用 ナノフィルトレーションの食品製造への応用

Falling in between reverse osmosis (RO) and ultrafiltration (UF), nanofiltration (NF) or loose RO, newly developed, is finding growing applications in the food industry which are reviewed.It is one of the most important properties of NF membrane that makes some solutes pass through or not rejected. NF membrane rejects uncharged molecules due to size exclusion and charged components due to electrostatic interaction between charged membrane and them. A negative rejection coefficient of a more permeable ion than the same charged ions in a solution by NF can be observed due to the Donnan effect, maintaining electroneutrality. These characteristics of NF have been exploited in the food industry.Applications of NF are summarized into five groups, as follows : 1) Desalination. 2) Concentration. Higher concentration of fruit juices by NF is established due to less different osmotic pressure across the membrane than RO. In the combination of 1) and 2), NF has been successfully applied into partial desalination and pre-concentration in the whey processing system of the dairy industry. 3) Fractionation due to size exclusion and/or electrostatic interaction has attracted researchers in separation of some oligosaccharides, amino acids and peptides from bio-products. 4) Decolorization. Color materials are easily rejected by NF. The lighter products from permeate of soy sauce or the imitated one have widened the soy sauce application area. 5) Taste modification. It was found that some unfavorable organoleptic materials in reconstituted skim milk are less rejected. The modified taste concentrate of it has been used for a non-fat milk product. A high grade ice cream, developed from NF concentrate of whole milk, gives us better taste due to less ash content of it and non-heat concentration.

THE TASTING PHENOMENON

Describes how and where we perceive the sense of taste, the traditional four basic taste sensations, and why different parts of the mouth are more or less sensitive to a particular one. Outlines types of compounds having a particular taste with some relationships between and anomalies of their chemical structure and the taste sensation they elicit, together with individual variation in tasting sensitivity and factors affecting this, such as adaptation. Summarizes interesting taste phenomena including: taste blindness; taste modification; the role of heavy metals in taste perception. Describes the additional taste sensations that have been proposed such as: umami; water‐taste; metallic; alkalinity and other gustatory effects such as pungency (burning sensation), cooling and astringency.

THE BIOCHEMISTRY OF MATURATION

Negative and positive aspects of maturation are respectively related to aroma and taste modifications. Vicinal diketones, hydrogen sulphide, acetyldehyde being primarily responsible for ‘green’ beer flavours an important feature of maturation is the adjustment of their concentration during the lagering period. The role of secondary fermentation in the removal of these undesirable by-products and the importance of sulphury compounds in determining the typical character of lager beer are reviewed. Particular emphasis is placed upon new enzymatic and genetic approaches to overcome vicinal diketone problems in accelerated fermentation systems using free and immobilized cells. The presence in beer of amino acids, peptides, nucleotides and organic as well as inorganic phosphates is, in part, due to the secretion of these materials by the yeast during lagering. Most of these compounds are contained in internal pools and their actual participation in flavour maturation depends upon intracellular breakdown and accumulation, changes in cell permeability and subsequent exchange possibilities between the yeast cell and the surrounding beer. Participation and practical implications of medium chain length fatty acids in the development of autolytic and yeasty flavours are discussed.

Selective suppression of judged sweetness by ziziphins

The effects of ziziphins and of control treatments upon judgments by human adults of the sweetness, sourness, bitterness, and saltiness of American apple cider or apple juice were measured with a category estimation method during repeated trials before, during (90 sec treatment duration only), and after, treatment. Sweetness was reduced after either a 10 sec or a 90 sec whole mouth treatment with ziziphins, but not after quinine sulfate or apple juice control treatment. No differences in after-treatment sourness, bitterness, or saltiness occurred between treatments. The reduction in sweetness was weak with 10 sec 3.5% W/V ziziphins treatment, but strong after 90 sec 0.88% W/V ziziphins treatment; duration of suppression was ca. 70 sec. The mechanism was identified as taste modification since adaptation, cross-adaptation, and mixture suppression were eliminated by control treatments and by post-treatment rests and rinse. Comparisons with known gumnemic acids effects suggest that net dissociation of ziziphins from taste receptor membranes and/or inactivation in the membrane may be much faster than with gymnemic acids.