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.     

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.     

Stability and sensory shelf life of orange juice pasteurized by continuous ohmic heating

Electrical heating of food products provides rapid and uniform heating, resulting in less thermal damage to the product. The objective of this research was to examine the effects of ohmic heating on the stability of orange juice with comparison to conventional pasteurization. During storage at 4 degrees C, degradation curves of ascorbic acid followed a linear decrease pattern in both ohmic-heated and conventionally pasteurized orange juices. For five representative flavor compounds (decanal, octana, limonene, pinene, and myrcene), higher concentrations were measured during storage in the ohmic-heated orange juice than in conventionally pasteurized juice. Although residual pectin esterase activity remained negligible in both types of juices, particle size was lower in the ohmic-heated orange juice. The sensory shelf life was determined by using the Weibull-Hazard method. Although both thermal treatments prevented the growth of microorganisms for 105 days, the sensory shelf life of ohmic-treated orange juice was >100 days and was almost 2 times longer than that of conventionally pasteurized juice.     

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.     

Distribution of volatile compounds in the pulp,cloud, and serum of freshly squeezed orange juice

The quantitative distribution of volatile compounds in the pulp, cloud, and serum of a freshly squeezed orange juice (cv. Naveline) was measured. Juice monoterpene and sesquiterpene hydrocarbons were primarily recovered from the pulp (74.0 and 87.2%, respectively) and cloud (7.3 and 14.9%, respectively). Esters and monoterpene alcohols were mainly found in the serum (90.4 and 84.1%, respectively). Long chain aliphatic aldehydes tend to concentrate in the pulp. The relative proportions of individual volatile compounds were similar in the pulp and cloud. Pulp and cloud alcohol insoluble residues exhibited similar compositions; half of them are made of nonwall proteins, and the rest are made of cell wall materials. Pulp and cloud total and neutral lipids had similar fatty acids distributions, although the cloud was much richer in total lipids than the pulp. No relationship was found between the retention of aroma compounds in the pulp or cloud and their AIR and lipid content or composition.     

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).     

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.     

Identification and aroma impact of norisoprenoids in orange juice

Four norisoprenoids, alpha-ionone, beta-ionone, beta-cyclocitral, and beta-damascenone, along with their putative carotenoid precursors, were identified in Valencia orange juice using time-intensity GC-O, GC-MS, and photodiode array HPLC. alpha-Ionone and beta-cyclocitral are reported in orange juice for the first time. GC-O aroma peaks were categorized into seven groups with similar sensory qualities: citrus/minty, metallic/mushroom/geranium, roasted/cooked/meaty/spice, fatty/soapy/green, sulfury/solventy/medicine, floral, and sweet fruity. The four norisoprenoids contributed approximately 8% of the total aroma intensity and 78% of the total floral aroma category. The putative carotenoid norisoprenoid precursors, alpha- and beta-carotene, alpha- and beta-cryptoxanthin, and neoxanthin, were identified in the same orange juice using photodiode array HPLC retention times and spectral characteristics.     

Carotenoid profile modification during refrigerated storage in untreated and pasteurized orange juice and orange juice treated with high-intensity pulsed electric fields

A comparative study was made of the evolution and modification of various carotenoids and vitamin A in untreated orange juice, pasteurized orange juice (90 degrees C, 20 s), and orange juice processed with high-intensity pulsed electric fields (HIPEF) (30 kV/cm, 100 micros), during 7 weeks of storage at 2 and 10 degrees C. The concentration of total carotenoids in the untreated juice decreased by 12.6% when the juice was pasteurized, whereas the decrease was only 6.7% when the juice was treated with HIPEF. Vitamin A was greatest in the untreated orange juice, followed by orange juice treated with HIPEF (decrease of 7.52%) and, last, pasteurized orange juice (decrease of 15.62%). The decrease in the concentrations of total carotenoids and vitamin A during storage in refrigeration was greater in the untreated orange juice and the pasteurized juice than in the juice treated with HIPEF. During storage at 10 degrees C, auroxanthin formed in the untreated juice and in the juice treated with HIPEF. This carotenoid is a degradation product of violaxanthin. The concentration of antheraxanthin decreased during storage, and it was converted into mutatoxanthin, except in the untreated and pasteurized orange juices stored at 2 degrees C.     

Linalool in orange juice: origin and thermal stability

Linalool concentrations were determined in juice from three groups of 60 Valencia oranges using pentane:ether extraction and high-resolution capillary GC. The outer peel (flavedo) was removed from one group. The other two groups retained their peel intact. Juice was extricated from the halved fruits of the flavedo-less group and from one of the peel-intact groups using a hand reamer. A peel-cutting/macerating juice extractor was used for the other peel-intact group. Linalool concentrations were 0.004 mg/L in peeled fruit juice and 0.020 and 0.106 mg/L for hand-reamed and mechanically extracted peel-intact juice, respectively. Juice from peeled fruit contained significantly (P < 0.05) less linalool than peel-intact juice. Approximately 80% of the total juice linalool content was associated with peel using reamer design, and 96% was associated with peel-cutting/macerating design. Linalool increased with increasing peel oil levels; however, the increases were not proportionate. Since all commercial juices are mechanically extracted, the vast majority of linalool in commercial orange juice originates from the peel and not from the juice vesicle cytoplasm. Juice from peel-macerated, mechanically extracted fruit increased from 0.106 to 0.134 mg/kg after thermal processing, whereas juice from reamer extraction was essentially unchanged.     

Capillary electrophoresis analysis of orange juice pectinesterases

Pectinesterase (PE) was extracted from orange juice and pulp with 1 M NaCl, desalted, and separated using capillary electrophoresis (CE) gel procedures (CE-SDS-CGE) and isoelectric focusing (CE-IEF). PE resolved as a single peak using noncoated fused silica columns with CE-SDS-CGE. CE-IEF separation of PE required acryloylaminoethoxyethanol-coated columns, which had limited stability. Thermal stability of PE extracts before and after heating at 75 degrees C for 30 min and at 95 degrees C for 5 min established heat labile and heat stabile fractions with identical PE migration times by CE-SDS-CGE or CE-IEF. Peak magnitude decreased to a constant value as heating time increased at 75 degrees C. Regression analysis of CE-SDS-CGE peak migration times of molecular weight (MW) standards estimated both heat labile and heat stable PE at MW approximately 36 900. Traditional SDS-PAGE gel separation of MW standards and active PE isolated by IEF allowed estimation of MW approximately 36 000. CE-SDS-CGE allowed presumptive, but not quantitative, detection of active PE in fresh juice.     

Bioavailability and antioxidant effects of orange juice components in humans

Seven healthy females and six males consumed daily 256 mg of vitamin C, 271 mg of flavanones (mainly as glycosides), 6 mg of carotenoids (mainly xanthophylls and cryptoxanthins), and 0.16 mg of folate by incorporation of daily three times 236 mL of not from concentrate orange juice (OJ) into their habitual diet. At the end of 3 weeks, mean vitamin C, folate, carotenoid, and flavanone plasma concentrations increased significantly relative to baseline by 59% (p < 0.001), 46% (p = 0.018), and 22% (p < 0.001), and 8-fold (p = 0.045), respectively. Flavanones were excreted in urine 9-fold more at the end of the intervention (p = 0.01) but returned to baseline 2 days after study completion. After the 3 week intervention, plasma concentrations of vitamins A and E did not change. 8-Hydroxydeoxyguanosine in white blood cells declined by 16% (p = 0.38; n = 11), and in individuals with high baseline concentrations by 29% (p = 0.36; n = 7), respectively. Low-density lipoprotein (LDL)-/high-density lipoprotein (HDL)-cholesterol ratios decreased but cholesterol (HDL, LDL, total) and thiobarbituric acid reactive substance plasma concentrations did not change significantly. We conclude from this pilot study that OJ is an excellent food source to enhance circulating concentrations of valuable hydrophilic as well as lipophilic phytochemicals.     

Solid phase microextraction (SPME) of orange juice flavor: odor representativeness by direct gas chromatography olfactometry (D-GC-O)

The sensorial quality of solid phase microextraction (SPME) flavor extracts from orange juice was measured by direct gas chromatogrphy-olfactometry (D-GC-O), a novel instrumental tool for evaluating odors from headspace extracts. In general, odor impressions emerging from SPME extracts poorly resembled that of the original orange juice. In an attempt to improve the sensorial quality of extracts, sample equilibration and exposure times were varied on Carboxen/polydimethylsiloxane (CAR/PDMS) and divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) SPME fibers. Best sensorial results were obtained with the DVB/CAR/PDMS fiber exposed for the shortest time; a trained panel of eight assessors judged its odor as the most representative of the reference orange juice. The analysis of odor active compounds by classical GC-O accounted for odor characteristics revealed by D-GC-O. A principal component analysis (PCA) was applied on SPME and headspace extracts using flavor recoveries as variables. Interestingly, PCA discriminated samples according to their odor representations described by D-GC-O analysis. This paper provides the first comprehensive methodology to "smell" SPME extracts and "evaluate" their sensorial quality. This method will enable future investigations to further improve SPME performance.     

Discrimination between orange juice and pulp wash by (1)H Nuclear Magnetic Resonance spectroscopy: identification of marker compounds

The potential of NMR spectroscopy and multivariate analysis methods to detect the adulteration of orange juice with pulp wash is demonstrated. Principal component analysis has been applied to (1)H NMR spectra of >300 orange and pulp wash juices, and stepwise linear discriminant analysis was used to classify the samples. A model with six principal components gave a high success rate of classification (94%) for both training and validation sets. An important principal component loading showed that dimethylproline played a key role in the discrimination between the two types of juice, with higher levels in pulp wash. Dimethylproline was not previously known as a marker compound for orange juice adulteration. An ANOVA test revealed at least 21 other NMR signals that differed significantly between the authentic and pulp wash groups. The compounds they represent could be seen as potential marker compounds in addition to dimethylproline. This makes NMR with chemometrics an attractive screening tool with advantages in terms of rapidity, simplicity, and diversity of information provided.     

Liquid chromatographic determination of naringin and neohesperidin as a detector of grapefruit juice in orange juice

Naringin/neohesperidin ratios can be used to differentiate orange juice which may contain added grapefruit juice from orange juice which may include juices from other naringin-containing cultivars. The naringin/neohesperidin ratios in juice vary from 14 to 83 in grapefruit (C. grandis) and from 1.3 to 2.5 in sour orange (C. aurantium) cultivars; the ratio is always less than 1 for the K-Early tangelo. Concentrations of both naringin and neohesperidin can be determined in orange juice by using a single liquid chromatographic isocratic reverse-phase system with a C-18 column. The detection limit for both compounds is 1 ppm with a linear working range to 500 ppm. Concentration relative standard deviations range from 0.47 to 1.06% for naringin and from 0.4 to 1.27% for neohesperidin. Naringin and neohesperidin recoveries ranged from 93 to 102% at concentrations of 5 and 50 ppm. Naringin values from blind duplicate samples of orange/grapefruit juice blends could be duplicated to +/- 3%.     

In vitro availability of flavonoids and other phenolics in orange juice

Hand-squeezed navel orange juice contains 839 mg/L phenolics, including flavanones, flavones, and hydroxycinnamic acid derivatives. The flavanones are the main phenolics in the soluble fraction (648.6 mg/L) and are also present in the cloud fraction (104.8 mg/L). During refrigerated storage of fresh juice (4 degrees C), 50% of the soluble flavanones precipitate and integrate into the cloud fraction. Commercial orange juices contain only 81-200 mg/L soluble flavanones (15-33%) and the content in the cloud is higher (206-644 mg/L) (62-85%), showing that during industrial processing and storage the soluble flavanones precipitate and are included in the cloud. An in vitro simulation of orange juice digestion shows that a serving of fresh orange juice (240 mL) provides 9.7 mg of soluble hesperidin (4'-methoxy-3',5,7-trihydroxyflavanone-7-rutinoside) and 4.7 mg of the C-glycosylflavone vicenin 2 (apigenin, 6,8-di-C-glucoside) for freshly squeezed orange juice, whereas pasteurized commercial juices provide 3.7 mg of soluble hesperidin and a higher amount of vicenin 2 (6.3 mg). This means that although orange juice is a very rich source of flavanones, only a limited quantity is soluble, and this might affect availability for absorption (11-36% of the soluble flavanones, depending on the juice). The flavanones precipitated in the cloud are not available for absorption and are partly transformed to the corresponding chalcones during the pancreatin-bile digestion.     

Gas chromatographic determination of fatty acids and sterols in orange juice

A gas chromatographic (GC) method has been developed for the simultaneous quantitation of fatty acids and sterols in orange juice, using a bonded phase fused silica capillary column of intermediate polarity, splitless automatic injection, and flame ionization detection. Sample preparation has been simplified by using 1 g C-18 adsorbent in a disposable minicolumn to extract 2 mL orange juice. Methylation of fatty acids and silylation of the sterols were carried out in the eluted extract (low polarity lipid fraction). The method precision was 7%; recoveries ranged from 83 to 113%. The precision of the injection technique was 2%. Seven major fatty acids and 5 sterols in orange juice were quantitated by the GC method and identified by GC/mass spectrometry. Quantitative data for several orange juice samples indicated that the levels of the compounds of interest were in the 1.3-72.0 mg/L range. The results demonstrate that bonded phase fused silica capillary GC has great versatility and potential for the quantitative determination of fatty acids and sterols.     

Anaerobic digestion of wastewater derived from the pressing of orange peel generated in orange juice production

A study of the anaerobic digestion of wastewater from the pressing of orange peel generated in orange juice production was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (37 degrees C). Prior to anaerobic treatment the raw wastewater was subjected to physicochemical treatment using aluminum sulfate as a flocculant and to pH reduction using a solution of sulfuric acid. The reactor was batch fed at COD loads of 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0 g of COD. The process was very stable for all of the loads studied, with mean pH and alkalinity values of 7.5 and 3220 mg of CaCO3/L, respectively. The anaerobic digestion of this substrate was found to follow a first-order kinetic model, from which the specific rate constants for methane production, K(G), were determined. The K(G) values decreased considerably from 0.0672 to 0.0078 L/(g h) when the COD load increased from 1.5 to 5.0 g of COD, indicating an inhibition phenomenon in the system studied. The proposed model predicted the behavior of the reactor very accurately, showing deviations of <5% between the experimental and theoretical values of methane production. The methane yield coefficient was found to be 295 mL of CH4 STP/g of COD removed, whereas the mean biodegradability of the substrate (TOC) was 88.2%. A first-order kinetic model for substrate (TOC) consumption allowed determination of the specific rate constants for substrate uptake, K(C), which also decreased with increasing loading, confirming the above-mentioned inhibition process. Finally, the evolution of the individual volatile fatty acid concentrations (acetic, C2; propionic, C3; butyric, C4; isobutyric, iC4; valeric, C5; isovaleric, iC5; and caproic, C6) with digestion time for all loads used was also studied. The main acids generated were acetic and propionic for all loads studied, facilitating the conversion into methane.     

Liquid chromatographic methodology for the characterization of orange juice

Liquid chromatographic (LC) methodology potentially useful for the characterization of orange juice, with particular regard to detecting adulteration of orange juice by computer pattern recognition analysis, has been developed. After dilution with methanol the juice is extracted with hexane to remove the carotenoids, which are chromatographed on a C18 column with an acetonitrile-methanol-methylene chloride mobile phase and detection at 450 nm. Further extraction of the juice with methylene chloride isolates the methoxylated flavones, which are chromatographed by reverse phase LC with an acetonitrile-methanol-water mobile phase and detection at 280 nm. The flavanone glycosides remaining in solution are chromatographed on a C18 column with an acetonitrile-water mobile phase and detection at 280 nm. The precisions of the heights of the 32 LC peaks selected for pattern recognition analysis were determined from 5 replicate analyses of a single juice. Coefficients of variation of the replicates ranged from 0.3 to 4.5%, with an average of 2.1%. Adulteration of products with sodium benzoate-fortified pulpwash or grapefruit juice can be detected by this method. Pattern recognition analysis of the data obtained for 80 authentic and 19 adulterated orange juices showed that the method is potentially useful for distinguishing between authentic and adulterated products.