Flavor release and perception in hard candy: influence of flavor compound-compound interactions

The influence of flavor compound-compound interactions on flavor release properties and flavor perception in hard candy was investigated. Hard candies made with two different modes of binary flavor delivery, (1) L-menthol and 1,8-cineole added as a mixture and (2) L-menthol and 1,8-cineole added separate from one another, were analyzed via breath analysis and sensory time-intensity testing. Single-flavor candy containing only L-menthol or 1,8-cineole was also investigated via breath analysis for comparison. The release rates of both L-menthol and 1,8-cineole in the breath were more rapid and at a higher concentration when the compounds were added to hard candy separate from one another in comparison to their addition as a mixture (conventional protocol). Additionally, the time-intensity study indicated a significantly increased flavor intensity (measured as overall cooling) for hard candy made with separate addition of these flavor compounds. In conclusion, the flavor properties of hard candy can be controlled, at least in part, by flavor compound-compound interactions and may be altered by the method of flavor delivery.     

Flavor release and perception in hard candy: influence of flavor compound-flavor solvent interactions

The release kinetics of l-menthol dissolved in propylene glycol (PG), Miglyol, or 1,8-cineole (two common odorless flavor solvents differing in polarity and a hydrophobic flavor compound) were monitored from a model aqueous system via atmospheric pressure chemical ionization mass spectrometry (APCI-MS). Breath analysis was also conducted via APCI-MS to monitor release of l-menthol from hard candy that used PG and Miglyol for l-menthol incorporation. The quantities of l-menthol released when dissolved in PG or Miglyol from the model aqueous system were found to be similar and overall significantly greater in comparison to when dissolved in 1,8-cineole. Analogous results were reported by the breath analysis of hard candy. The release kinetics of l-menthol from PG or Miglyol versus from 1,8-cineole were notably more rapid and higher in quantity. Results from the sensory time-intensity study also indicated that there was no perceived difference in the overall cooling intensity between the two flavor solvent delivery systems (PG and Miglyol).     

Model studies on the influence of coffee melanoidins on flavor volatiles of coffee beverages

Addition of the total melanoidin fraction isolated by water extraction from medium-roasted coffee powder to a model solution containing a set of 25 aroma compounds mimicking the aroma of a coffee brew reduced, in particular, the intensity of the roasty, sulfury aroma quality. Model studies performed by static headspace analysis revealed that especially three well-known coffee odorants, that is, 2-furfurylthiol (FFT), 3-methyl-2-butene-1-thiol, and 3-mercapto-3-methylbutyl formate, were significantly reduced in the headspace above an aqueous model solution when melanoidins were added. In particular, the low molecular weight melanoidins (1500-3000 Da) led to the most significant decrease in FFT. In contrast, for example, aldehydes remained unaffected by melanoidin addition.     

Glycosidically bound volatiles and flavor precursors in Laurus nobilis L

Glycosidically bound volatile compounds in different parts (leaves and buds) of Laurus nobilis L. were investigated. After isolation of extracts obtained by Amberlite XAD-2 adsorption and methanol elution, glycosides were analyzed after enzymatic hydrolysis by GC-MS or directly after trifluoroacetyl (TFA) derivatization by GC-MS in EI and NCI mode. In the leaves most of the glycosidically bound volatiles occur as beta-D-glucopyranosides. Among the disaccharides, primeverosides are predominant; smaller amounts of alpha-L-arabinofuranosyl-beta-D-glucopyranosides, rutinosides, and vicianocides could also be identified. Major aglycons comprised benzyl alcohol, some linalool-diols, 2-hydroxy-1,8-cineole and its derivatives such as 2,3-dehydro-1,8-cineole, sobrerols, and menthadien-8-ols. Among the identified nor-carotenoids, 3-oxo-alpha-ionol, the corresponding 7,8-dihydro derivative, and vomifoliol are predominant in leaves. 3-Hydroxy-beta-damascone and 3-hydroxy-7,8-didehydro-beta-ionol, precursors of the sensorially active damascenone, were identified only in the buds.     

Influence of flavor solvent on flavor release and perception in sugar-free chewing gum

The influence of flavor solvent [triacetin (TA), propylene glycol (PG), medium chained triglycerides (MCT), or no flavor solvent (NFS)] on the flavor release profile, the textural properties, and the sensory perception of a sugar-free chewing gum was investigated. Time course analysis of the exhaled breath and saliva during chewing gum mastication indicated that flavor solvent addition or type did not influence the aroma release profile; however, the sorbitol release rate was statistically lower for the TA formulated sample in comparison to those with PG, MCT, or NFS. Sensory time-intensity analysis also indicated that the TA formulated sample was statistically lower in perceived sweetness intensity, in comparison with the other chewing gum samples, and also had lower cinnamon-like aroma intensity, presumably due to an interaction between sweetness intensity on aroma perception. Measurement of the chewing gum macroscopic texture by compression analysis during consumption was not correlated to the unique flavor release properties of the TA-chewing gum. However, a relationship between gum base plasticity and retention of sugar alcohol during mastication was proposed to explain the different flavor properties of the TA sample.     

Effect of beta-cyclodextrin on aroma release and flavor perception

Binding and release of volatile compounds to and from beta-cyclodextrin were measured in model aqueous systems using static equilibrium headspace and dynamic headspace dilution. Beta-cyclodextrin decreased the static equilibrium headspace for some volatiles (e.g., ethyl octanoate and decanone) due to binding, but dilution studies demonstrated that binding was readily reversible. Dynamic release of hydrophobic volatile compounds was similar to that observed from emulsions. When beta-cyclodextrin was added to fat free yogurt, the release of a commercial lemon flavoring was modified and was similar to release from a regular fat yogurt. Sensory difference testing confirmed the release results. The data demonstrate that beta-cyclodextrin can be used to modify flavor delivery in both model and real systems; the effects in the latter are sensorially significant.     

Identification of sulfur volatiles in canned orange juices lacking orange flavor

The purpose of this study was to understand why some canned orange juices are not perceived as orange juice. Sensory flavor profile data indicated that the primary odor (orthonasal) attributes were tropical fruit/grapefruit, cooked/caramel, musty, and medicine. By comparison fresh-squeezed juice lacked these odor attributes. GC-O analysis found 43 odor-active components in canned juices. Eight of these aroma volatiles were sulfur based. Four of the 12 most intense aroma peaks were sulfur compounds that included methanethiol, 1-p-menth-1-ene-8-thiol, 2-methyl-3-furanthiol, and dimethyl trisulfide. The other most intense odorants included 7-methyl-3-methylene-1,6-octadiene (myrcene), octanal, 2-methoxyphenol (guaiacol), 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone (homofuraneol), (E)-non-2-enal, (E,E)-deca-2,4-dienal, 4-hydroxy-3-methoxybenzaldehyde (vanillin), and alpha-sinensal. Odorants probably responsible for the undesirable sensory attributes included grapefruit (1-p-menth-1-ene-8-thiol), cooked [2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (Furaneol), and 3-(methylthio)propanal (methional)], musty [7-methyl-3-methylene-1,6-octadiene and (E)-non-2-enal], and medicine (2-methoxyphenol). The canned juices also lacked several aldehydes and esters normally found in fresh orange juice.     

Sweetener/sweetness-induced changes in flavor perception and flavor release of fruity and green character in beverages

Green leaf volatile (GLV) mixtures, commercial orange flavors, and commercial strawberry flavors were applied to beverage bases in which concentrations of citric acid as well as a sweetener (sucrose or aspartame/acesulfame-K) were varied. Sensory profiling showed that flavor-specific fruity character increased as perceptible sweetness increased, independent of whether the sweetness resulted from sucrose (a change from 9 to 12 Brix) or aspartame/acesulfame-K (a change from 0.2 to 0.4 Brix). Sweetness was affected only by the tastants in the base and not by the flavors, although flavor-specific interactions between sweetener type and sweetener level occurred. Flavor release from the sucrose bases was compared to flavor release from bases containing aspartame/acesulfame-K by static headspace measurements and by MS-Nose measurements using an artificial throat. These measurements showed greater flavor volatility from bases having low Brix (fewer soluble solids). This negative Brix effect was also evident in the sensory data for perception of some GLV green notes. The headspace data could not support a positive Brix effect, the typical salting out, which would correspond to the observed perceptual enhancement of fruity notes.     

Sensory and instrumental analyses of volatiles generated during the extrusion cooking of oat flours

Three batches of oats were extruded under four combinations of process temperature (150 or 180 degrees C) and process moisture (14. 5 and 18%). Two of the extrudates were evaluated by a sensory panel, and three were analyzed by GC-MS. Maillard reaction products, such as pyrazines, pyrroles, furans, and sulfur-containing compounds, were found in the most severely processed extrudates (high-temperature, low-moisture). These extrudates were also described by the assessors as having toasted cereal attributes. Lipid degradation products, such as alkanals, 2-alkenals, and 2, 4-alkadienals, were found at much higher levels in the extrudates of the oat flour that had been debranned. It contained lower protein and fiber levels than the others and showed increased lipase activity. Extrudates from these samples also had significantly lower levels of Maillard reaction products that correlated, in the sensory analysis, with terms such as stale oil and oatmeal. Linoleic acid was added to a fourth oat flour to simulate the result of increased lipase activity, and GC-MS analysis showed both an increase in lipid degradation products and a decrease in Maillard reaction products.     

Characterization of odor-active volatiles in apples: influence of cultivars and maturity stage

The aroma and texture of three different apple cultivars, harvested at three maturity stages, were analyzed by sensory and instrumental analysis. The emphasis was on the identification of the most potent odorant volatiles, and the challenge was to separate the few most important flavor compounds, which may be trace chemicals, from the vast number of nonodorant compounds present in apple aroma extracts. Thirty-six odorant compounds were detected, 24 of which were common to all extracts. A significant correlation coefficient was found between the aroma intensity scores and overall quantity of the odorant volatiles, which shows that the development of sensory aroma is similar to that of odorant volatiles. This study also showed that the parameters measured by penetrometry and compression were highly correlated with sensory textural attributes. The determination of the optimal maturity stage for different apple cultivars by the usual parameters, such as color, diameter, total soluble solids, and titrable acidity, may not be sufficient to determine the optimal sensory quality for consumers. Moreover, the sensory quality of fruits changes during maturation in a different way from one cultivar to another, and this should be taken into account.     

The role of fat in flavor perception: effect of partition and viscosity in model emulsions

Decreasing the fat content of a food, while maintaining the same aroma content, changes both aroma release (due to partition effects) and the viscosity of the food. To understand the relative contribution of these two factors on flavor perception, a series of flavored emulsions were prepared to control aroma release and viscosity using different aroma, oil, and hydroxypropyl methyl cellulose (HPMC) contents. Samples were formulated to deliver the same aroma-release in vitro and in vivo, and their viscosity was measured using the Kokini oral shear stress parameter. Despite the in vivo aroma release being constant, there were perceptual differences between the samples, and the flavor intensity decreased as in-mouth viscosity increased. For these iso release samples, the Kokini oral shear stress parameter correlated well with the decrease in perception, suggesting that there may be a viscosity stimulus or that the viscosity affects release of tastant and hinders aroma-taste interactions.     

Effect of temperature and pH on the generation of flavor volatiles in extrusion cooking of wheat flour

Extrusion temperature (120, 135, and 150 degrees C) and quantity of added sodium hydroxide (0, 3, and 6 g/kg feedstock) were used as variables to study flavor generation in extrusion cooking of wheat flour. In total, 127 volatile components were identified in the extrudates, of which 51 contained sulfur. The levels of pyrroles, thiophenes, thiophenones, thiapyrans, and thiazolines increased at higher extrusion temperatures, whereas furans and aldehydes decreased. The addition of sodium hydroxide also affected the formation of volatile compounds. However, thiophenes, thiophenones, polythiacycloalkanes, thiazoles, thiazolines, pyrroles, and some pyrazines tended to increase with the more alkaline extrusion conditions. Some compounds from lipid-Maillard interactions were identified in the extrudates. Analysis of the volatile components by gas chromatography-olfactometry showed sulfur- and nitrogen-sulfur-containing heterocycles as possible contributors to the sulfury and rubbery odors observed in extrudates produced at the higher temperature and more alkaline conditions.     

Formation of flavor oil microemulsions, nanoemulsions and emulsions: influence of composition and preparation method

This study aimed to establish conditions where stable microemulsions, nanoemulsions or emulsions could be fabricated from a nonionic surfactant (Tween 80) and flavor oil (lemon oil). Different colloidal dispersions could be formed by simple heat treatment (90 °C, 30 min) depending on the surfactant-to-oil ratio (SOR): emulsions (r > 100 nm) at SOR < 1; nanoemulsions (r < 100 nm) at 1 < SOR < 2; microemulsions (r < 10 nm) at SOR > 2. Turbidity, electrical conductivity, shear rheology, and DSC measurements suggested there was a kinetic energy barrier in the oil-water-surfactant systems at ambient temperature that prevented them from forming metastable emulsion/nanoemulsion or thermodynamically stable microemulsion systems. High energy homogenization (high pressure or ultrasonic homogenizer) or low energy homogenization (heating) could be used to form emulsions or nanoemulsions at low or intermediate SOR values; whereas only heating was necessary to form stable microemulsions at high SOR values.     

重庆地区酸性紫色土锌有效性及其影响因素研究

以重庆地区紫色土为对象,研究了重庆地区酸性紫色土Zn有效性及主要影响因素。结果表明:供试紫色土全Zn含量为40.2～89.6mg/kg,有效Zn含量在0.2～4.2mg/kg之间;用直线、幂函数和指数函数回归方程对影响有效Zn的主要土壤因素进行回归拟合,土壤有效Zn与土壤全Zn、有机质、全N含量呈极显著正相关关系,相关系数依次为0.5243**、0.5308**、0.5097**;而与全P含量相关性显著(r=0.4637*);与土壤pH值呈极显著负相关关系(r=-0.5698**);通径分析表明,土壤理化性质对有效Zn的直接作用系数大小次序为全Zn全NpH,土壤全Zn对Zn有效性的直接作用最为明显。     

Characterization of the essential oil volatiles of Satureja thymbra and Satureja parnassica: influence of harvesting time and antimicrobial activity

Seasonal variation in chemical composition of essential oils obtained from Satureja parnassica subsp. parnassica Heldr. & Sart ex Boiss. and Satureja thymbra L. was determined by GC and GC-MS analysis. The in vitro antibacterial activities of these essential oils were evaluated at two different initial levels against two common foodborne bacteria. Their minimum inhibitory concentration (MIC) and noninhibitory concentration (NIC) values were determined via an innovative automated technique, which was applied on a Malthus apparatus combining the conductance measurements with the common dilution method. The essential oil concentration fluctuated greatly during the period examined and established that the Satureja oils obtained during the flowering period were the most potent, exhibiting the lowest MIC values and retaining remarkable bactericidal properties. Thus, they represent an inexpensive source of natural antibacterial substances that exhibit potential for use in food systems to prevent the growth of foodborne bacteria and to extend the shelf life of the processed food.     

Potential soil acidity: Notions and parameters

It was shown that the value determined in the course of soil analysis and characterizing the potential acidity depends on the equilibrium pH of the soil suspension. The increase in potential acidity observed with increasing pH is related to the properties of soil horizons and the nature of the soil constituents controlling the potential acidity. The ratio between the levels of the potential acidity parameters was estimated. Based on the studies performed and literature data, amendments were proposed for the conceptual and terminological system used in Russia related to potential soil acidity.