Flavor Changing Research Articles

Novel Insight into the Formation of Odour-Active Compounds in Sea Buckthorn Wine and Distilled Liquor Based on GC-MS and E-Nose Analysis.

Sea buckthorn wine (SW) and distilled liquor (DL) are fruit wines with beneficial health effects. However, their unpleasant flavour limits their development and widespread acceptance. Therefore, it is necessary to analyse their flavour composition and changes. In this study, differential metabolites of sea buckthorn DL during processing were analysed, and the relationships between E–nose sensor values and key volatile organic compounds (VOCs) were established. The results show that 133 VOCs were identified, with 22 aroma–contributing components. Fermentation significantly increased the content of VOCs, especially esters. A total of seven and 51 VOCs were significantly upregulated after fermentation and distillation, respectively. Meanwhile, seven sensors were positively correlated with the increased level of alcohols and esters, and reflected the increasing trends of 10 key VOCs.

Effects of dietary thiamin on flesh quality in grass carp ( Ctenopharyngodon idella )

An 8 week experiment was conducted to assess the effect of dietary thiamin on meat quality of grass carp. Totally, 540 fish were randomly distributed into 18 cages (1.4 m × 1.4 m × 1.4 m) each containing 30 fish in three replicates. Test fish were fed with respective diets for four times daily: 0.12 (thiamin un-supplemented diet), 0.43, 0.83, 1.25, 1.62 and 2.04 mg thiamin/kg diet. Results revealed that optimum dietary thiamin improves grass carp flesh quality in five aspects: (1) increased nutritional quality (fillet protein, lipid contents) was associated with increasing target of rapamycin and casein kinase 2 expression, (2) improved flesh flavour via increasing the flavour amino acids contents (Glu, Asp, Gly, Ala, Leu and Ile), (3) elevated fillet healthcare components contents (especially docosahexaenoic acid and eicosapentaenoic acid contents), (4) improved sensory characteristics (pH, firmness, water-holding capacity) of flesh and (5) enhanced flesh antioxidative capacity by elevating the activities and expression of antioxidant enzymes, which was involved in elevating Nrf2 expression and down-regulating Keap1a and Keap1b expression. Dietary thiamin affected fish flesh quality correlated with changes in muscle flavour, healthcare components, sensory characteristics, antioxidant capacity, target of rapamycin and Nrf2 expression.

Changes in texture, rheology and volatile compounds of golden pomfret sticks inoculated with Shewanella baltica during spoilage

Shewanella baltica has a high spoilage ability to decompose nutrients in fish. To investigate the role of S. baltica in fish protein and flavour during spoilage, the texture, rheology, protein patterns and volatile compounds of golden pomfret inoculated with S. baltica during 10-day storage were tested. During storage, S. baltica reduced the hardness of fish sticks by 29.73–49.24 %. Compared to the control (G0′: 20.27 ± 2.15 kPa), inoculated samples showed lower moduli (G0′: 16.71 ± 0.82–17.50 ± 1.80 kPa). Their myosin heavy chains, myosin-binding protein C and actin were decomposed into smaller proteins, which was validated by the lower intensities of molecules with Mw 160–176 kDa. Furthermore, S. baltica generated volatile spoilage markers, including dimethyl sulfide, 2-methyl-butanal and 3-methyl-butanal. This study reveals the mechanism of fish texture and flavour changes induced by S. baltica, and provides insights into controlling bacterial spoilage of seafood.

Melatonin stimulates postharvest ripening of apples by up-regulating gene expression of ethylene synthesis enzymes

Melatonin has been implicated in the regulation of ripening in several types of climacteric fruits, but its role in apple is poorly understood. In this study, the effectiveness of melatonin in influencing postharvest ripening in apples and interacting with ethylene biosynthesis process was investigated. Apples of four local cultivars (Golden, Reineta, Blanquina and Rabiosa) were harvest at an immature green stage and immersed for 120 min in a solution with water (control), melatonin 50 µM, ACC 1 mM, and melatonin 50 µM + ACC 1 mM. The evolution of apple quality parameters and ethylene production was assessed in all cultivars for 35 days after treatment. In addition, Golden apple was used to examine the transcript abundance of ethylene biosynthesis enzymes genes in the skin and flesh. Exogenous melatonin improved apple quality during postharvest ripening and stimulated ethylene production in all cultivars studied, advancing the timing of the climacteric burst. Melatonin-induced changes in ethylene production correlated well with changes in fruit quality and were in part similar to those induced by the ethylene precursor ACC, so ethylene appears to be a target of melatonin. In Golden apple, melatonin stimulated the expression of MdACS1 and MdACO1 genes, which showed a climacteric profile similar to that of ethylene. The transcriptional effects of exogenous melatonin on ethylene-related genes was also more notable in the skin than in the flesh, suggesting an initiating role of the former in the biosynthesis of the phytohormone. Taken together, the results point to the fact that exogenous melatonin may be useful in improving apple quality during postharvest ripening by promoting colour and flavour change and extending fruit firmness. The effect of melatonin appears to be mediated in part by up-regulation of the transcriptional activity of the MdACS1 and MdACO1 genes during the climacteric peak, thus contributing to an increase in ethylene availability.

Effect of Extended Postmortem Aging on Beef Muscles of Differing Quality Grade during Retail Display

Aging of beef subprimals is a common industry practice to improve tenderness. However, the effect of extended aging (up to 63 d) on retail shelf life, tenderness, and eating quality of beef strip loin and sirloin of differing quality grades is not clearly understood. Therefore, in the current study, longissimus dorsi (strip loin) and gluteus medius muscles (sirloin) were collected from USDA Choice or Select carcasses and fabricated into 6 portions. Each of these portions was designated to an assigned time of wet aging (14, 21, 28, 35, 45, or 63 d) in vacuum bags. After aging, samples were fabricated into steaks and placed into a multideck retail display case for 72 h. Steaks were evaluated for color (instrumental and color panelists) every 8 h during retail display, and Warner-Bratzler shear force and sensory analysis were conducted after retail display. The results were analyzed using the PROC MIXED procedure of SAS with repeated measures for the color data. Among the effects evaluated (aging, quality grade, and aging×quality grade), quality grade was not significant (P>0.05) for either strip loin or sirloin steaks. An aging×display hour interaction was identified (P<0.05) for the color measurements. In general, as aging time increased over the display period, color was negatively impacted. Although tenderness improved (P<0.05) with aging, the incidence of off-flavors also increased, especially in sirloin steaks, suggesting that beef processors need to consider flavor changes during extended aging.

Effect of salt penetration and water migration on cooked salted egg yolk gel during storage: Physicochemical properties, structural characteristics and flavor changes

There is an urgent need to explore the salt penetration and water migration in the cooked salted egg yolk (CSEY) gel. The aim of this study was to investigate the effect of salt and water on the physicochemical, structural and flavor characteristics of CSEY gel stored at 25 °C. The hardness of the yolk increased significantly (608.0 g → 2730.7 g) during storage. The results of LF-NMR showed that the free water content in the yolk gel was enhanced. The microstructure of CSEY could be observed by SEM, which showed that during storage, polyhedral particles were dispersed due to the heating process. In addition, ethyl acetate (71.9 %) was completely undetectable in the CSEY-21 d. In summary, the sample at and before 14 d of storage had good processing value. Therefore, this work would provide theoretical guidance for the low-sodium pickling of SEY (salted egg yolk) and its suitable storage methods.

Dynamic change of bacterial diversity, metabolic pathways, and flavor during ripening of the Chinese fermented sausage.

Chinese fermented sausage is a famous fermented meat product with a complex microbiota that has a potential impact on flavor and quality. In this study, Lactobacillus plantarum MSZ2 and Staphylococcus xylosus YCC3 were used as starter cultures to investigate the change in bacterial diversity, metabolic pathways, and flavor compounds during the ripening process of fermented sausages. High-throughput sequencing technology and headspace solid-phase microextraction-gas chromatography–mass spectrometry (HS-SPME-GC/MS) were applied for characterizing the profiles of bacterial diversity, metabolic pathways, and flavor compounds in sausage samples on days 0, 6, and 12 during ripening. Results showed that Lactobacillus, Staphylococcus, Lactococcus, Leuconostoc, and Weissella were the most abundant bacterial genera found in the sausage samples during all stages of fermentation. Functional prediction reveals the abundance of 12 different metabolic pathways, the most important pathways are carbohydrate metabolism, nucleotide metabolism, lipid metabolism, and amino acid metabolism. A total of 63 volatile compounds were successfully identified in fermented sausage samples. Correlational analysis demonstrated that Staphylococcus and Leuconostoc were closely related to the formation of flavor compounds. Therefore, the present study may provide guidance for future use of microbiota to improve flavor, quality, and preservation of fermented sausages.

A novel postharvest preservation technology of fruit—Intermittent high oxygen treatment: A case study on “Lingwu” long jujube

AbstractFresh “Lingwu” long jujube (Ziziphus jujuba cv. Mill) fruit is susceptible to softening, water loss, and flavor change during storage. The effect of intermittent high oxygen treatment (IHOT) on the quality of jujube was investigated, which was immersed in the oxygen concentration of 50% and 90% for 30 min every week along with 8 weeks of storage at 0 ± 1°C. Significantly, the firmness, weight loss, soluble solids content (SSC), and membrane integrity were significantly retarded in 50% and 90% IHOT. Meanwhile, the activities of peroxidase (POD) were maintained a higher level after 35 d storage in 50% IHOT. And the activities of alcohol dehydrogenase (ADH) were significantly inhibited, and the peak was delayed by 50% IHOT. Furthermore, polyphenol oxidase (PPO) activity was barely changed during the first 28 days of storage, and the lowest enzymatic activity was shown later in the 50% IHOT. These results indicated that the short‐term HOIT with appropriate concentration (50%) delayed the softening, maintained the moisture content and membrane integrity, and modulated key metabolic pathways of jujube fruit. As a whole, the applicability of IHOT could prolonged the shelf life of fresh jujube, which shows a great potential, in the application of fruit preservation.Practical applicationsEvaluation of different oxygen concentrations and treated models on jujube fruit helps the development of preservation technology for extending the shelf life of fruits. The application of intermittent high oxygen treatment to the fruits and vegetables was helpful to a novel postharvest preservation technology and the development of the fresh jujube fruit market.

Flavor formation based on lipid in meat and meat products: A review.

Meat product is popular throughout the world due to its unique taste. Flavor is one of the most important quality characteristics of meat products and also is a key influencing factor in the overall acceptability of meat products. The flavor of meat products is formed by precursors undergoing a series of complex reactions. During meat product processing, lipids are hydrolyzed by lipase to produce flavor precursors such as free fatty acid, then further oxidized to form volatile flavor compounds. This review summarizes lipolysis, lipid oxidation, and interaction of lipid with Maillard reaction and amino acid during meat products processing and storage as well as influencing factors on lipid degradation including raw meat (source of meat, feeding pattern, and castration), processing methods (thermal processing, nonthermal processing, salting, and fermentation) and additives. Meanwhile, the volatile compounds produced by lipids in meat products including aldehydes, alcohols, ketones, and hydrocarbons are summed up. Analytical methods of volatile compounds and the application of lipidomics analysis in mechanisms of flavor formation of meat products are also reviewed. PRACTICAL APPLICATIONS: Flavor is one of the most important quality characteristics of meat products, which influences the acceptability of meat products for consumption. Lipids play an important role in the flavor formation of meat products. Understanding the relationship between flavor compounds and changes in lipid compositions during the processing and storage of meat products will be helpful to control the quality of meat products.

Comprehensive Analysis of the Neutrino Process in Core-collapsing Supernovae

We investigate the neutrino flavor change effects due to neutrino self-interaction and shock wave propagation, as well as the matter effects on the neutrino process in core-collapsing supernovae (CCSNe). For the hydrodynamics, we use two models: a simple thermal bomb model and a specified hydrodynamics model for SN1987A. For the presupernova model, we take an updated model, adjusted to explain SN1987A, which employs recent developments in the (n, γ) reaction rates for nuclei near the stability line (A ∼ 100). As for the neutrino luminosity, we adopt two different models: equivalent neutrino luminosity and nonequivalent luminosity models. The latter is taken from a synthetic analysis of CCSN simulation data, which quantitatively presented the results obtained by various neutrino transport models. Relevant neutrino-induced reaction rates are calculated using a shell model for light nuclei and a quasiparticle random phase approximation model for heavy nuclei. For each model, we present abundances of the light nuclei (7Li, 7Be, 11B, and 11C) and the heavy nuclei (92Nb, 98Tc, 138La, and 180Ta) produced by the neutrino process. The light nuclei abundances turn out to be sensitive to the Mikheyev–Smirnov–Wolfenstein (MSW) region around O-Ne-Mg layer while the heavy nuclei are mainly produced prior to the MSW region. Through detailed analyses, we find that neutrino self-interaction becomes a key ingredient, in addition to the MSW effect, for understanding the neutrino process and the relevant nuclear abundances. The normal mass hierarchy is shown to be more compatible with the meteorite data. The main nuclear reactions for each nucleus are also investigated in detail.

Technology characteristics and flavor changes of traditional green wheat product nian zhuan in Northern China.

Nian zhuan has its aroma as one of the perceived principal characteristics. The current study was aimed mainly to investigate the potential to include the aroma of nian zhuan as a new target criterion into the green wheat product chain. By improving the conditions for the traditional processing of nian zhuan, the optimal processing conditions were determined as green wheat (GW) 14 d, steaming the green wheat with the skin (SGWS) 26 min and cooked green wheat peeled (CGWP) 280 min, to evaluate the feasibility of using electronic nose (E-nose) and gas chromatography mass spectrometry (GC-MS) to discriminate nian zhuan in different stages. E-nose was used to recognize nian zhuan odors in different processing stages, and GC-MS to identify the individual volatile compounds. A total of 139 volatile compounds were detected by GC-MS, of which 71 key were screened by t-test (P < 0.01). The W1W, W1S, W2W and W2S sensors of E-nose gave higher responses to all samples, and effectively discriminated the samples. The most volatile compounds were produced in the millstone milling (MSM) stage of nian zhuan, and millstone could promote the release of volatile compounds from cooked green wheat by milling.

Quality assessment of royal jelly based on physicochemical properties and flavor profiles using HS-SPME-GC/MS combined with electronic nose and electronic tongue analyses

Royal jelly (RJ) is known for its unique flavor and nutritional value. However, the flavor changes of RJ during storage remain unclear. In this work, the flavor profiles of RJ during storage were evaluated by using headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with both electronic nose and electronic tongue analyses. Results revealed that the moisture, water-soluble protein, and whiteness were changed significantly at 25 °C. The holistic variation of RJ flavor exhibited evident distinction based on principal component analysis with electronic nose and electronic tongue. Among the total of 37 volatile compounds identified in RJ, the octanoic acid showed the highest contents of 47.61 % at 25 °C in 21 d. Seven volatile compounds, i.e., 2(3H)-furanone,5-butyldihydro-, 2-heptanone, trans-β-ocimene, 2-nonen-4-one, 2-nonanone, methyl benzoate, and 2-octenoic acid (E), contributed largely to the typical overall flavor of RJ. This work provides an improved understanding of the flavor change of RJ during storage.

Reach and complementarity of mu rightarrow e searches

In Effective Field Theory, we describe mu leftrightarrow e flavour changing transitions using an operator basis motivated by experimental observables. This implies that mu rightarrow e_L gamma , mu rightarrow e_L bar{e} e and mu rightarrow e_L conversion on nuclei probe a six-dimensional subspace, where we derive constraints on the New Physics scale from past and future experiments, illustrating the complementarity of the processes in an intuitive way.

Transcriptomic and Metabolomic Profile Analysis of Muscles Reveals Pathways and Biomarkers Involved in Flavor Differences between Caged and Cage-Free Chickens.

The cage-free system has gained a lot of interest in recent years because it can offer chickens more freedom and is easier to manage compared with free-range rearing systems, but few studies have focused on the effect of the cage-free rearing system on meat quality and flavor. In this study, 44 Jianghan chickens were reared in caged or cage-free systems to explore the effect of different rearing systems on meat-eating quality. Sensory evaluation of cooked muscles showed that the leg muscle aroma, juiciness, and flavor intensity significantly improved by the cage-free rearing. The cage-free hens had significantly lower body weight, abdominal fat percentage, and meat fat content, but higher meat moisture content. The cage-free group had brighter breast muscle and redder leg muscle color 24 h after slaughter. Transcriptomic and metabolomic profile analysis of the leg muscle samples showed that the cage-free rearing changed biosynthesis pathways associated with glycogen metabolism, lipid and fatty acid biosynthesis and transport, muscle cellular type, and cellular components, which were related to raw meat quality. Different rearing systems also resulted in differences in glycolipid metabolism, lipid metabolism, and altered levels of intramuscular fat content and other flavor precursors. Pathways such as glycerolipid metabolism, adipocytokine signaling, and metabonomic pathways such as linoleic acid, glycerophospholipid, arginine, proline, and β-alanine metabolism may be responsible for the meat quality and flavor change.

Characterization and spoilage potential of Bacillus cereus isolated from farm environment and raw milk.

Bacillus cereus sensu lato (B. cereus sl) is important spoilage bacteria causing milk structure and flavor changes and is ubiquitous in the environment. This study addresses the biodiversity, toxicity, and proteolytic activity of B. cereus sl from 82 environmental samples and 18 raw bovine milk samples from a dairy farm in the region of Tianjin. In sum, 47 B. cereus sl isolates were characterized through biochemical tests, 16S rRNA gene sequencing, and panC gene analysis. Fourteen sequence types (STs) of B. cereus sl were found in raw bovine milk samples, and five new STs (ST2749, ST2750, ST2751, ST2752, and ST2753) were identified in this study. ST1150 was the dominant ST, associated with fecal, air, drinking water, teat skin, teat cup, and teat dip cup. The results of toxin gene analyses showed that 12.77% and 8.51% of isolates carried hblACD and nheABC operons, respectively. In addition, the detection rate of emetic cesB gene was 21.28%. B. cereus sl demonstrated high spoilage potentials even at 7°C, which has the proteolytic activity of 14.32 ± 1.96 μmol of glycine equivalents per ml. Proteolytic activities were significantly (p < 0.05) decreased after the heat treatment. The residual activity of protease produced at 7°C was significantly higher than that produced at 25°C and 37°C after treatment at 121°C for 10 s and 135°C for 5 s (p < 0.01). Together, the results provide insights into the characteristics of B. cereus sl from farm environment and raw bovine milk and revealed that B. cereus sl contamination should also be monitored in raw milk for ultra-high temperature (UHT) products. This knowledge illustrates that strict cleaning management should be implemented to control B. cereus sl and assure high-quality milk products.

Changes in the Primary Metabolites of 'Fengtang' Plums during Storage Detected by Widely Targeted Metabolomics.

Plums are one of the most popular stone fruits worldwide owing to their high nutritional value. After harvest, plum fruit quality and flavor change during storage; however, little is known about the changes in metabolites during this period. A comprehensive comparison of primary metabolites in ‘Fengtang’ plum fruits during storage is performed using widely targeted primary metabolomics. A total of 272 primary metabolites were identified by means of ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS) in the plums at different storage periods. There was a significant increase in the relative amounts of twenty-eight lipids, twenty amino acids and their derivatives, thirteen organic acids, ten saccharides and alcohols, six nucleotides and their derivatives, and two vitamins. A Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of differential metabolites revealed that glucosinolate biosynthesis, starch and sucrose metabolism, ascorbate and aldarate metabolism, lysine degradation, and other metabolic pathways were significantly enriched; therefore, changes in these metabolic pathways may be key to the quality and flavor change in ‘Fengtang’ plum fruits during storage. Our results provide a theoretical foundation and technical support to evaluate ‘Fengtang’ plum fruit quality.

Effects of high‐pressure processing on aquatic products with an emphasis on sensory evaluation

SummaryPrevious intensive research has described the molecular impacts of high‐pressure processing (HPP) on fish meat chemical composition, such as myofibril structural proteins, enzymes, myoglobin and lipids. This work aims to collect articles on sensory evaluation of pressure‐treated aquatic products to determine the practical effects of HPP on aquatic products, especially sensory properties, by comparing the differences between instrumental tests and sensory evaluation, between trained sensory assessors and consumers to guide and improve the processing of aquatic products. The findings indicate that laboratory devices such as spectrophotometers, texture analysers and electronic noses, and trained sensory assessors can detect pressure‐induced changes in appearance, texture, off‐odour, and flavour, such as discoloration, whitening, increased hardness and initiation of lipids oxidation. However, consumers did not perceive the pressure‐induced changes in odour and colour. Besides, consumers' attitudes towards pressure‐treated aquatic products are ambiguous in the range of 300 to 600 MPa, and professional testing and assessment fail to replace hedonic tests. In complex matrices of aquatic products, particular attention is needed to be paid to changes in sensory qualities dominated by microorganisms, endogenous enzymes and bioactive compounds after HPP treatment and throughout commercial storage.

Transcriptome analysis reveals mechanisms of acetylsalicylic acid-mediated fruit quality maintenance in fresh-cut kiwifruit

Postharvest ripening and processing of fresh-cut (FC) kiwifruit brings quality deterioration and spoilage, including substantial changes in fruit color, texture and flavor. Hence, a series of preservation techniques have emerged to reduce postharvest loss and maintain FC kiwifruit quality. In this study, we evaluated the efficacy of acetylsalicylic acid (ASA), a derivative of plant endogenous hormone salicylic acid, in preserving the quality and delaying the ripening process of FC kiwifruit. Compared to the control fruit, ASA treatment maintained a better fruit appearance and higher fruit firmness, as well as reducing mass loss, total soluble solids and ethylene production. Based on the RNA-seq data and weighted gene co-expression network analysis (WGCNA), eight biosynthetic genes were identified as involved in fruit quality change, which participates in cell wall metabolism, starch degradation/sugar accumulation and ethylene biosynthesis. Moreover, the analysis showed that four transcription factors were significantly induced by exogenous ASA treatment. Dual-luciferase assays proved that ASA-responsive transcription factors regulated fruit quality-related genes, resulting in delaying ripening process and extending the shelf-life of FC kiwifruit. This study showed that ASA effectively delayed the ripening process, and AcWRKY7/AcDOF21/AcC2H2–151/AcbHLH123 are associated with the ASA-mediated fruit quality maintenance.

Analysis of volatile flavor changes of sea urchin gonads and phospholipids after heating based on GC‐IMS

To study the relationship between sea urchin phospholipids (SUP) and sea urchin gonads (SUG) in flavor production, volatile flavor components of SUG and SUP were analyzed and characterized with gas-ion mobility spectrometry (GC-IMS) combined with a flavor analyzer (Flavourspec®-G.A.S). A total of 48 volatile flavor compounds, mainly aldehydes (29), ketones (6), and esters (4), were identified in the heated SUG and SUP. By constructing flavor fingerprints of SUG and SUP, significant changes of flavor compounds were observed before and after heating. It was shown that some volatile compounds were detected in both SUG and SUP, such as E-2-octanal, 3-methylbutyraldehyde, 2,3 pentanedione, 2-pentylfuran, and trimethyl pyrazine, which were presumed to be mainly generated from flavor precursors in SUP after heating. Principal Component Analysis (PCA) showed significant differences of volatile flavor in SUG and SUP before and after heating, suggesting that heating played an important role in flavor production in sea urchins. Therefore, SUP heated was responsible for key flavor substances production in SUG, which can provide a scientific basis for the flavor fortmation mechanism of sea urchins. Novelty Impact Statement Analysis of the role of phospholipids on sea urchin flavor formation by comparing the flavor changes of sea urchin gonads and sea urchin phospholipids after heating will help understand the flavor formation mechanism in foods. Flavor components in sea urchin gonads and phospholipids were significantly changed after heating suggested that heating plays an important role in flavor production. Changes in phospholipids in sea urchin gonads may be related to changes in flavor.

Wine Closure Performance of Three Common Closure Types: Chemical and Sensory Impact on a Sauvignon Blanc Wine

A Napa Valley Sauvignon blanc wine was bottled with 200 each of a natural cork, a screw cap, and a synthetic cork. As browning is an index for wine oxidation, we assessed the brown color of each bottle with a spectrophotometer over 30 months. A random-effects regression model for longitudinal data on all bottles and closure groups found a browning growth trajectory for each closure group. Changes in the wine’s browning behavior at 18 months and 30 months showed that the browning of the wine bottles appeared to slow down later in the storage period, especially for natural corks. The between-bottle variation was the highest for the natural cork. At 30 months, we separated the bottles by the extent of browning and samples were pulled from the high, mid, and low levels of browning levels for each closure. The degree of browning is inversely correlated with free SO2 levels ranging from 5 to 12 mg/L. However, a Quantitative Descriptive Analysis (QDA™) sensory panel could not detect any difference in their aroma and flavor profile between closure types regardless of browning level. Even low levels of free SO2 retain protection against strong oxidation aromas, and visual browning detected by spectrophotometer seemed to precede oxidative aroma and flavor changes of the aging Sauvignon blanc.