Using severity factor as a parameter to optimize krill treatment under subcritical water conditions

The aim of this study was to optimize the conditions for subcritical water treatment of krill, as expressed with a single parameter: the severity factor (log R₀). Raw krill was treated under subcritical water conditions at various log R₀ values (1.54–3.75) by varying the treatment temperatures (120–180 °C) and times (0–10 min) in two different sizes of batch-type vessel (10 and 117 mL). The log R₀ value could efficiently describe changes in various properties of the obtained liquid extracts and solid residues. The most desirable shrimp-like flavor intensity and highest sensory preference were obtained for log R₀ values of 2.75–3.01. The results also proved that severity factor can be used as a single parameter to control subcritical water treatment conditions in differently sized batch-type vessels to produce shrimp-like flavor extract and residue from krill.     

Characterization of newly developed pepper cultivars (Capsicum chinense) ‘Dieta0011-0301’, ‘Dieta0011-0602’, ‘Dieta0041-0401’, and ‘Dieta0041-0601’ containing high capsinoid concentrations and a strong fruity aroma

ABSTRACT

Capsaicinoids are responsible for the pungent flavor of peppers (Capsicum sp.). The cultivar CH-19 Sweet is a non-pungent pepper mutant that biosynthesizes the low-pungent capsaicinoid analogs, capsinoids. Capsinoids possess important pharmaceutical properties. However, capsinoid concentrations are very low in CH-19 Sweet, and Capsicum cultivars with high content capsinoids are desirable for industrial applications of capsinoids.

Habanero, Bhut Jolokia, and Infinity are species of Capsicum chinense, and have strong pungency and intense fruity flavors. In the present study, we report new cultivars with high concentrations of capsinoids (more than ten-fold higher than in CH-19 Sweet), and showed that these cultivars (Dieta0011-0301 and Dieta0011-0602 from Bhut Jolokia, Dieta0041-0401 and Dieta0041-0601 from Infinity) are of nutritional and medicinal value and have fruity aromas. We also obtained a vanilla bean flavor, vanillyl alcohol, and vanillyl ethyl ether from capsinoids in the fruit of these cultivars following the addition of ethanol at room temperature.     

Metabolic engineering of aroma components in fruits

Plants have the ability to produce a diversity of volatile metabolites, which attract pollinators and seed dispersers and strengthen plant defense responses. Selection by plant breeders of traits such as rapid growth and yield leads, in many cases, to the loss of flavor and aroma quality in crops. How the aroma can be improved without affecting other fruit attributes is a major unsolved issue. Significant advances in metabolic engineering directed at improving the set of volatiles that the fruits emit has been aided by the characterization of enzymes involved in the biosynthesis of flavor and aroma compounds in some fruits. However, before this technology can be successfully applied to modulate the production of volatiles in different crops, further basic research is needed on the mechanisms that lead to the production of these compounds in plants. Here we review the biosynthesis and function of volatile compounds in plants, and the attempts that have been made to manipulate fruit aroma biosynthesis by metabolic engineering. In addition, we discuss the possibilities that molecular breeding offers for aroma enhancement and the implications of the latest advances in biotechnological modification of fruit flavor and aroma.     

Area Postrema Cell Types that Mediate Nausea-Associated Behaviors

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The contribution of aromatic components in Katsuobushi to preference formation and reinforcement effect

Katsuodashi, a dried bonito broth, is very basic and indispensable in Japanese cuisine and contains taste-exhibiting components and unique aroma. We previously reported that its unique aroma contributes to the preference and reinforcement effect associated with dried bonito. This study aims to elucidate the contribution of aromatic components in Katsuobushi to preference formation and reinforcement effect. Volatile components obtained from dried bonito were fractionated and the fractions were subjected to two-bottle choice test. The fractionation test suggested that the component responsible for the preference is not one but comprises multiple components. In the GC–MS analysis/reconstruction test, solution with aromatic flavor narrowed down to 125 compounds had preference, and also had reinforcement effect. Moreover, GC–MS–olfactometry analysis narrowed down the candidate components to 28 out of 125. Mice showed preference for the test solution with aromatic flavor reconstructed with 28 components but did not show reinforcement behavior.     

Kinetic study of controlled release of flavor compounds from spray-dried encapsulated yeast powder using dynamic vapor sorption–gas chromatography

The release profile of d-limonene and ethyl hexanoate was investigated using a dynamic vapor sorption (DVS) system coupled with gas chromatography. The flavors were encapsulated by spray drying using Saccharomyces cerevisiae cells from which β-glucan had been partially extracted. Relative humidity (RH) was stepped from 20% to 50, 60, 70, and 80% at 30, 40, 50, and 60ºC. The maximum release flux for d-limonene and ethyl hexanoate was around 12 and 28 mg/s?m²?g-powder at 80% RH and 60ºC incubation. The Weibull distribution function was well fitted with the experimental data to analyze release kinetics. The release mechanism parameter was greater than 1.0, which indicates a controlled release with initial induction time. The activation energy for ethyl hexanoate (6 kJ/mol) was lower than d-limonene (41 kJ/mol) at 80% RH, which indicates higher affinition of ethyl hexanoate to migrate from the lipid bilayer membrane towards the water phase.     

The impact of lactic acid bacteria on cheese flavor

Abstract Chesse flavor is a manifestation of complex interactions of volatile and non-volatile flavor-active compounds plus tactual perception. Numerous agents, including lactic acid bacteria, procece the flavou sensations. The effect of lactic acid bacteria is more dominant in cheese varieties with limited growth of secondary flora. This review describes the indirect and direct impacts of lactic acid bacteria in cheese with emphasis on carbohydrate fermentation, changes in oxidation-reduction potential, interactions with non-starter bacteria, autolysis, proteolytic and peptidolytic activities, transport of metabolites and flavor production.