Flavor Stability Research Articles

Exploring Aldehyde Release in Beer by 4-Vinylpyridine and the Effect of Cysteine Addition on the Beer’s Pool of Bound Aldehydes

As a continuation of our previous work, which concerned the binding of aldehydes to bisulfite and cysteine, this article presents more results on the applicability of 4-vinylpyridine addition to beer prior to analysis aiming at release of aldehydes from these preformed bound states, thus making them quantifiable with the headspace solid-phase microextraction method combined with gas chromatography-mass spectrometry. This article also presents the first results on spiking beer samples with cysteine prior to forced-aging, pointing to the important role of cysteine in beer flavor stability. Both the levels in free and bound aldehydes show a relatively large degree of variation among different beers, but also between marker aldehydes. For some aldehydes (e.g., hexanal), the bound amount was shown to increase rather strongly upon forced beer aging, whereas for others (e.g., 2-methylpropanal), large amounts appeared to already be present in a bound state in the fresh samples. Spiking beer samples with cysteine prior to aging significantly lowered the aldehyde levels compared with nonspiked samples. Flavor stability of the cysteine-spiked beers was thereby greatly improved through aldehyde-cysteine adduct formation. It was further hypothesized that, in addition to efficient binding of aldehydes, cysteine also inhibits the formation of furfural during beer aging from Maillard reaction intermediates.

Breeding of lipoxygenase-1-less malting barley variety ‘SouthernStar’ and evaluation of malting and brewing quality

The lipoxygenase-1-null (LOX-less) trait has positive effects on beer quality, and in particular, improvement of flavor stability by reduction of beer deteriorating substances such as trans-2-nonenal (T2N). ’SouthernStar’ was successfully developed as the first LOX-less malting barley variety in Australia by introducing LOX-less trait into ‘Flagship’ by successive backcross and molecular marker assisted selection (MMAS). ‘Flagship’ is a two-rowed malting barley variety in Australia and it was used as the recurrent parent for the successive backcrossing. The yield potential, agronomic performance, disease resistance and the general malting quality were almost identical between ‘SouthernStar’ and ‘Flagship’. To evaluate effects of LOX-less trait on beer quality, the brewing trials were conducted using a pilot-scale brewing apparatus. The wort and beer quality were similar between ‘SouthernStar’ and ‘Flagship’. The effect of the LOX-less trait on the reduction of beer deteriorating substances such as T2N and trihydroxyoctadecenoic acid (THOD) contents was clearly verified in this study. The scores for total staleness of the test beers were significantly lower than those of the control beers under several storage conditions in one trial.

Influence of malt source on beer chemistry, flavor, and flavor stability

Beverage quality in the brewing industry is heavily influenced by ingredient properties. The contribution of raw ingredients such as yeast and hops to beer flavor is well understood. However, the influence of barley genotype and/or environment on flavor (the malt 'source') is largely unexplored. Here, a study was performed to determine (i) if there are metabolite differences among six commercial malt sources, (ii) if differences in malt chemistry are reflected in the chemistry of the beer, and (iii) if the differences in the beer chemistry impact sensory attributes of beer, through flavor and flavor stability. Six distinct sources of malts (six varieties from three maltsters) were brewed into six beers using a recipe designed to evaluate differences in flavor. Metabolomics and ionomics was used to characterize chemical variation among the six malts and beers using UHPLC- and HILIC-MS (non-volatile metabolites), HS-SPME/GC–MS (beer volatiles), and ICP-MS (malt metals). These analyses detected a total of 5042 compounds in malt, of which 217 were annotated and included amines, amino acids, fatty acids/lipids/fatty acyls, saccharides/glucosides/sugar acids/sugar alcohols, carboxylic acid derivatives, organic acids, phenolics/benzenoids, purines, pyrimidines/pyridines, terpenes, and organosulfurs. A total of 4568 compounds were detected in beer, of which 246 were annotated and included esters, aldehydes, and alcohols. Statistical analysis revealed chemical variation among the six malts (50/217 malt metabolites varied) and beers (150/246). The six beers were evaluated for flavor using a modified descriptive analysis for 45 sensory traits at 0, 4, and 8 weeks of storage at 4 °C. Principal component analysis of the sensory data revealed flavor differences among the six beers at 8 weeks, and the malt-type Full Pint was described as fruity and Meredith as corn chip. The metabolite and sensory data were integrated and revealed associations between flavor profiles in beer and the annotated malt and beer. The fruity or corn chip flavor profiles in beer were associated beer purines/pyrimidines, volatile ketones, amines, and phenolics, and malt lipids, saccharides, phenols, amines, and alkaloids. Taken together, these data support a role of malt source in beer flavor and flavor stability. As a raw ingredient, malting barley genotypes can be evaluated for a contribution to flavor, and this may be a future target for plant breeding, agronomy, and malting efforts to selectively improve flavor, flavor stability, and quality in beer.

Identification of Microflora in a Biological Brewer’s Wort Acidification Process Run Continuously for 20 Years

Biological acidification is a common and beneficial way for breweries to adjust the pH value of their mash or wort to improve enzymatic activity during mashing, raise yeast activity during fermentation, and increase the flavor stability of the finished beer. The reactors are mostly run for many years without re-inoculating a fresh culture, creating the possibility of changes in the culture, genetic drifts, or the survival of different strains. In this study, a biological acidification culture that had been continuously run for 20 years was analyzed by GTG5 PCR and IGS2-314 rDNA PCR fingerprinting, as well as 16S and 26S rDNA sequencing, and real-time PCR was applied to differentiate the bacterial and yeast strains and species. The applied real-time PCR primers for Lactobacillus amylolyticus and Lactobacillus amylovorus have not been published yet. It was shown that only strains of the species L. amylolyticus were present, with low contamination of yeast strains from the species Saccharomyces cerevisiae. As the original starter culture was Lactobacillus amylolyticus, the acidification plant ran for 20 years, and no Lactobacillus sp. cross-contamination could be analyzed using culture-dependent methods after 20 years. The microflora composition is a decisive factor for the final beer flavor.

Phenolic Substances in Beer: Structural Diversity, Reactive Potential and Relevance for Brewing Process and Beer Quality.

For the past 100 years, polyphenol research has played a central role in brewing science. The class of phenolic substances comprises simple compounds built of 1 phenolic group as well as monomeric and oligomeric flavonoid compounds. As potential anti- or prooxidants, flavor precursors, flavoring agents and as interaction partners with other beer constituents, they influence important beer quality characteristics: flavor, color, colloidal, and flavor stability. The reactive potential of polyphenols is defined by their basic chemical structure, hydroxylation and substitution patterns and degree of polymerization. The quantitative and qualitative profile of phenolic substances in beer is determined by raw material choice. During the malting and brewing process, phenolic compounds undergo changes as they are extracted or enzymatically released, are subjected to heat-induced chemical reactions or are precipitated with or adsorbed to hot and cold trub, yeast cells and stabilization agents. This review presents the current state of knowledge of the composition of phenolic compounds in beer and brewing raw materials with a special focus on their fate from raw materials throughout the malting and brewing process to the final beer. Due to high-performance analytical techniques, new insights have been gained on the structure and function of phenolic substance groups, which have hitherto received little attention. This paper presents important information and current studies on the potential of phenolics to interact with other beer constituents and thus influence quality parameters. The structural features which determine the reactive potential of phenolic substances are discussed.

Determination of Volatile Markers from Magnum Hops in Beer by In-Tube Extraction—Gas Chromatography—Mass Spectrometry

ABSTRACTA chromatographic method was developed for the identification of volatile markers from Magnum hops in two types of beer. The study was initially performed with Magnum hop pellets and hop essential oil and subsequently with traditional and flavored beer during the primary fermentation. The volatile compounds were isolated employing the in-tube extraction (ITEX) technique followed by identification and quantification through gas-chromatography—mass spectrometry (GC-MS) operating in scan mode. The main authentication markers identified in traditional beer were from aromatic compounds, aldehydes and alcohol esters. The most predominant authentication marker compounds in beer flavored with Magnum hop essential oil were obtained from terpenoids, followed by acid esters, alcohol esters and alcohol classes. A unique feature of this study was represented by the discriminant markers for the authentication of Magnum hop variety, identified in hop pellets, hop essential oil and flavored beer. The application of this methodology can be used for optimization of brewing technology and process parameters in view of prolonging fruity hop flavor stability of Romanian beers.

Stability and release behavior of encapsulated flavor from spray-dried Saccharomyces cerevisiae and maltodextrin powder

Yeast cells (Saccharomyces cerevisiae), from which β-glucans have been partially extracted, were used to encapsulate flavor inside the lipid bilayer membrane as natural encapsulant. The focus of this study was to investigate the release and stability of flavors (d-limonene and ethyl hexanoate) encapsulated in yeast cells and maltodextrin (MD) (DE = 19) by spray drying. The release behavior of encapsulated flavors from yeast cells was measured at 40, 60, 80, and 105 °C with different moisture content (0, 50, 100, and 200% of powder). Water affected flavor release from the yeast cells. The release rate constants were correlated using Gaussian distribution of the activation energy of the release rate constants. The release of d-limonene from the spray-dried MD powder showed a different trend than that of yeast cells at various temperatures. The activation energies of the release rate constant for ethyl hexanoate and d-limonene from yeast were 55 and 49 kJ/mol, respectively, under a wet condition. The formation rates of limonene oxide and carvone were slower in yeast than that of MD powder at 30 °C after 2 months.

Construction of sake yeast with low production of dimethyl trisulfide precursor by a self-cloning method

Dimethyl trisulfide (DMTS) is the primary component responsible for "hineka", the stale aroma of Japanese sake. Deletion of the MRI1 or MDE1 gene of sake yeast, encoding 5'-methylthioribose-1-phosphate isomerase and 5'-methylthioribulose-1-phosphate dehydratase, respectively, has been reported to greatly reduce the amount of DMTS precursor (DMTS-P1) in sake and to suppress the formation of DMTS during storage. In this study, we constructed sake yeast strains lacking MRI1 gene function by a self-cloning method. Two methods were applied: in one, a stop codon was introduced in the MRI1 ORF by point mutation; in the other, the entire MRI1 ORF was deleted from the genome. In both methods, a plasmid vector containing drug-resistance and counter-selectable markers was used to introduce the mutation. We successfully obtained the strains, which did not contain the plasmid sequences, by both methods. Small-scale sake brewing tests using these SC strains (strains obtained by the self-cloning method) found that DMTS-P1 was hardly detected in sake brewed with SC strains, and DMTS production after sake storage was greatly reduced as compared with the parent strain. The components of brewed sake were almost the same between the SC and parent strains. These results suggest that SC strains can produce sake with higher flavor stability without changing the sake brewing properties.

Impacts of Copper, Iron, and Manganese Metal Ions on the EPR Assessment of Beer Oxidative Stability

ABSTRACTBeer flavor stability is a key quality parameter as brewers seek to maintain the quality of their product throughout the supply chain. The electron paramagnetic resonance (EPR) oxidative stability assay is one method that brewers are utilizing to optimize their process with regard to flavor stability without the time requirements of stored aging and sensory testing of beer. There are still gaps in our knowledge relating to the EPR measurement and the factors within the assay that affect the measured results. This investigation aimed to understand the influence that transition metal ions have on the measurement in four different beers (three lagers and one stout). The detrimental impact of copper and iron on the lag time (an indication of when staling may begin) of trial beers is demonstrated, while the influence of manganese is shown to differ between beers. The T450 value (an indication of how much staling may occur in a particular beer) is shown to increase with iron and manganese addition in most beers. However, copper reduces the T450 or maximum spin adduct concentration achieved and the potential reasons for this are discussed. Crucially for brewers, it has been shown that as little as a 10 ppb transition metal ion addition can make a detectable difference to the measured oxidative stability.

Natural Hardwood Smoked Sugar Improves Oxidative and Flavor Stability of Naturally Cured, Aerobically Packaged, Food Service Bacon

ObjectivesThe purpose of this study was to determine the effectiveness of adding naturally smoked sugar into a curing brine to prevent lipid oxidation and maintain flavor in naturally cured, frozen, aerobically packaged, food service bacon.Materials and MethodsFresh pork bellies (6.3 to 7.2 kg) were trimmed and cut in half yielding an anterior and posterior belly section. Within each belly, each section was randomly assigned to 1 of 2 treatments with a targeted 12% pump: a control brine or a curing brine with added natural hardwood smoked sugar (n = 15/treatment). Final target concentrations for control brine ingredients in the raw belly were 1.6% salt, 1.0% cane sugar and 0.8% cultured celery juice. Raw belly sections assigned to the naturally smoked sugar brine targeted 1.6% salt, 0.8% cane sugar, 0.8% cultured celery juice, and 0.6% smoked sugar (RA12032, Red Arrow Products, Manitowoc, WI). After injection, bellies were smoked and cooked to an internal temperature of 53°C using a standard bacon processing schedule. After cooking, bellies were chilled for 12 h. at 0 to 2°C then sliced 1.5 mm thick with a horizontal slicer from the anterior to posterior end. Slices were randomly selected from the sliced belly and laid out onto food service bacon sheet paper. Sheets of bacon slices were randomly assigned to 4 sensory frozen storage periods (0, 40, 80, and 120 d) or 7 thiobarbituric acid reactive substances (TBARS) frozen storage times (0, 20, 40, 60, 80, 100, and 120 d). All boxed bacon slices were stored aerobically at –18 ± 2°C for the designated storage period. After the appropriate frozen storage time, trained sensory panelists evaluated saltiness, smoke intensity, bacon flavor, oxidized flavor intensity, and other off-flavor intensity. The distillation method for TBARS analysis was utilized to measure lipid oxidation. Sensory and TBARS analysis were analyzed as a split-plot design with repeated measures with the whole plot consisting of the half belly and treatment with the split-plot consisting of storage day.ResultsThere was a Treatment × Day interaction (P < 0.001) for oxidized flavor intensity. Control bacon had increased (P < 0.001) panelist scores for oxidized flavor intensity from d 0 to 120. However, bacon manufactured with naturally smoked sugar had oxidative flavor intensity scores that remained constant (P > 0.936) over the 120 d of frozen storage. Additionally, trained panelists scored bacon samples manufactured with the naturally smoked sugar higher (P < 0.001) for saltiness, smoke intensity, and bacon flavor intensity compared to control samples. In confirmation of the oxidized flavors found during sensory evaluation, there was a Treatment × Day (P < 0.001) interaction found for TBARS values. The TBARS values for the control treatment displayed increased TBARS values from d 20 to d 120 (P < 0.001). Bacon formulated with naturally smoked sugar exhibited static TBARS values throughout the 120 d frozen storage period (P > 0.196).ConclusionThe ability of naturally smoked sugar to function as an antioxidant in sliced naturally cured bacon was confirmed with both sensory evaluations and objective measurement of lipid degradation products. Also, aerobically packaged, frozen, naturally cured bacon formulated without added antioxidants had significant challenges in flavor stability due to increased lipid oxidation as frozen storage length increased.

Utilization of Rosemary and Green Tea Extracts As Clean Label Antioxidant Solutions in Bacon Formulations

ObjectivesThe rising consumer preference for bacon as a center-of-the-plate item is associated with an increased demand for its food service applications. Maintaining flavor stability is critical where freezing without any oxygen barrier and a high variability in fat content and unsaturation of pork bellies can influence lipid oxidation and limit product shelf-life. Interest in natural cure ingredients is largely due to rising consumer demand for processed meats with clean label solutions. Rosemary and green tea extracts are naturally sourced antioxidants that could mitigate product quality issues while providing consumer-friendly labels. This research evaluated the effect of adding rosemary and green tea extracts on the keeping quality and shelf life of bacon using natural cure or conventional cure when stored in food service style packaging.Materials and MethodsPork bellies were manufactured into bacon under commercial conditions according to industry standards at the Michigan State University Meat Laboratory. Bellies were injected with a base formulation of 1.5% salt, 0.8% sugar, and water. The treatments include: (i) Conventional Cure (phosphates; sodium nitrite; sodium erythorbate; Control), (ii) Conventional Cure + 0.1% Herbalox (Rosemary Extract; CCR), (iii) Natural Cure (half the sodium nitrite content of the Control from pre-converted vegetable juice powder, PVJP; 500 ppm ascorbic acid from cherry powder; NC) + 0.1% Herbalox (Rosemary Extract; NCR), and (iv) Natural Cure (half the sodium nitrite content of the Control from PVJP, 200 ppm ascorbic acid from cherry powder; NC) + 0.2% Duralox (Rosemary/Green Tea Extracts blend; NCRT). After smoking (94.3 to 98.6% yield) and chilling, sliced bacon slabs were packaged to simulate food service conditions (oxygen-permeable polyvinyl lined boxes layered on wax-covered lined paper, frozen at –20°C) and stored for 45 or 90 d in the dark. Visual evaluation, lipid oxidation (hexanal, pentanal, heptanal) and descriptive sensory analysis were determined at the end of the respective storage times.ResultsLipid oxidation, measured as secondary oxidation products, increased in all treatments as storage time progressed. However, the addition of rosemary extract in conventionally cured bacon samples (CCR) improved oxidative stability as evidenced by lower concentrations of secondary oxidation markers after 45 and 90 d of frozen storage than the Control. Results of secondary oxidation products in naturally cured bacon samples (NCR, NCRT) have shown their comparable oxidative stability with the Control following 90 d of storage. Saltiness, Musty and Caramelized aromas and flavors assessed by a trained sensory panel were highest (P < 0.05) in CCR while Brown/Grilled Meat, Smoky, Fatty, Herbal, Sweet and Aftertaste descriptors were similar (P > 0.05) among all treatments following 90 d of frozen storage. Visual evaluation results showed all treatments to be acceptable across all storage periods.ConclusionAddition of rosemary and green tea extracts can enhance the shelf-life of bacon throughout 90 d of frozen storage and help maintain their keeping quality during food service packaging conditions. It provides the meat industry with a highly effective alternative to replace synthetic preservatives so processors can meet consumer demand for clean label products without compromising product shelf-life and quality.

Flavor and chiral stability of lemon-flavored hard tea during storage

Flavor stability of hard tea beverage was investigated over eight weeks of storage. The volatile compounds were analyzed using solid-phase microextraction-gas chromatography–mass spectrometry (SPME-GC–MS) and two-dimensional GC–MS. Quantitative analysis showed that the concentrations of linalool, citronellol, geranial, neral, geraniol, and nerol decreased dramatically during storage, whereas α-terpineol showed an increasing trend during storage. Heart-cut two-dimensional GC–MS (2D-GC–MS) chirality analysis showed that (R)-(+)-limonene, (R)-(−)-linalool, (S)-(−)-α-terpineol and (S)-(−)-4-terpineol dominated in the fresh hard tea samples, however, the configuration changed during storage for the terpene alcohols. The storage conditions did not change the configuration of limonene. A conversion of (R)-(−)-linalool to (S)-(+) form was observed during storage. Both (S)-α-terpineol and (S)-4-terpineol dominated at beginning of the storage, but (R)-(+)-α-terpineol became dominated after storage, suggested in addition to isomerization from (S)-α-terpineol, other precursors could also generate α-terpineol with (R)-isomer preference.

Freeze drying and vacuum impregnating characteristics of Nostoc sphaeroides Kützing

ABSTRACTNostoc sphaeroides Kützing (N. sphaeroides) is a kind of edible algae widely growing in China. The paper is aimed at developing a novel snack food of N. sphaeroides using vacuum impregnation. The samples from freeze drying (FD) have large volume and loose structure, which were found suitable for processing. With nuclear magnetic resonance and imaging, the water signal of N. sphaeroides was measured in FD, and different drying-stage raw N. sphaeroides were selected to impregnate by different solutions, when the products’ impregnated mass, water activity, and flavor difference were analyzed. Results indicate that the water distribution in FD was uniform. Sucrose impregnated product was stable with large impregnated mass and low water activity, whereas trehalose impregnated product was easy to separate from the solution with low sweetness. For the products with the raw N. sphaeroides dried for 9 and 12 h, no obvious difference was found in water activity and flavor. Result shows that N. sphaeroides dehydrated for 9 h in FD is suitable for vacuum impregnation, and different impregnated products are acceptable from the point of view of flavor and storage stability.

A preliminary study of the quality attributes of a cloudy wheat beer treated by flash pasteurization

Flash pasteurization (37 and 100 pasteurization units, PU) and conventional tunnel pasteurization (15 PU) processing of wheat beers were evaluated by examining their impacts on microorganisms, colour, colloidal haze and flavour stability during 84 days of storage at 20°C. The results revealed that the microbiological stability of 37 and 100 PU flash-pasteurized beers was comparable with that of the 15 PU sample, and the development of both yeast and lactic acid bacteria was inhibited for 84 days of storage. The conventional tunnel-pasteurized wheat beer resulted in a higher thermal load relative to the flash-pasteurized samples based on the results of oxidative stability. These three pasteurized beers showed a similar decrease in haze intensity throughout the storage period. Meanwhile, flash-pasteurized beers had better colour and colloidal haze stability than the tunnel-pasteurized beer. It was also found by dynamic light scattering analysis that the temperature in the flash pasteurizer has the desired effect on the protein denaturation and particle size distribution. Therefore, flash pasteurization is a promising method to increase the shelf-life of wheat beers instead of conventional tunnel pasteurization. Copyright © 2017 The Institute of Brewing & Distilling

The effect of homogenization pressure on the flavor and flavor stability of whole milk powder

Flavor is one of the key factors that can limit the application and shelf life of dried dairy ingredients. Many off-flavors are caused during ingredient manufacture that carry through into ingredient applications and decrease consumer acceptance. The objective of this research was to investigate the effect of homogenization pressure on the flavor and flavor stability of whole milk powder (WMP). Whole milk powder was produced from standardized pasteurized whole milk that was evaporated to 50% solids (wt/wt), homogenized in 2 stages with varying pressures (0/0, 5.5/1.4, 11.0/2.8, or 16.5/4.3 MPa), and spray dried. Whole milk powder was evaluated at 0, 3, and 6 mo of storage at 21°C. Sensory properties were evaluated by descriptive analysis. Volatile compounds were analyzed by sorptive stir bar extraction with gas chromatography-mass spectrometry. Fat globule size in condensed whole milk and particle size of powders were measured by laser diffraction. Surface free fat, inner free fat, and encapsulated fat of WMP were measured by solvent extractions. Phospholipid content was measured by ultra-high-performance liquid chromatography-evaporative light scattering. Furosine in WMP was analyzed by ultra-high-performance liquid chromatography-mass spectrometry. Increased homogenization pressure decreased cardboard and painty flavors, volatile lipid oxidation compound concentrations, fat globule size in condensed milk, surface free fat, and inner free fat in WMP. Encapsulated fat increased and phospholipid-to-encapsulated fat ratio decreased with higher homogenization pressure. Surface free fat in powders increased cardboard flavor and lipid oxidation. These results indicate that off-flavors were decreased with increased homogenization pressures in WMP due to the decrease in free fat. To decrease off-flavor intensities in WMP, manufacturers should carefully evaluate these parameters during ingredient manufacture.

Advances in anti-staling brewer's yeast

Brewer's yeast is crucial in beer fermentation, mainly beer flavor diversity and stability. Beer flavor stability is one of the most influential beer quality aspects, and screening or breeding brewer's yeast with enhanced anti-staling capacity will be an effective solution. In recent decades, with the progress of genetic engineering and detailed description of brewer's yeast genome, great efforts have been made to improve brewer's yeast. This review highlights recent advances in classical and genetic engineering improvement of yeasts to produce more antioxidant compounds or less beer aging substances and precursors. Therein, improvement targets, evaluation methods and development strategies of anti-staling brewer's yeast are also discussed. Furthermore, hotspot and future trend of anti-staling yeast strain development are also proposed.

Study on Proanthocyanidin-Rich Beer

As a large family of phenolic compounds, proanthocyanidins (PAs) possess antioxidant, anti-inflammatory, antihypertensive, and hypocholesterolemic activities. Regular consumption of PAs is beneficial to health, leading to decreased risk of cardiovascular diseases, cancers, and neurodegenerative diseases. The PA content in ordinary beer is low, and main PA sources are malts and hops. Lycium ruthenicum Murr. (LR) contains much higher PA content compared with hops and malts. Therefore, it can improve the PA content in beer when used as a material for beer brewing. In the present study, 1.5 g/L of LR was used as a raw material to brew lager beer of 12°P. The result showed that PA content was increased from about 10 to 68 mg/L in finished beer, and the total polyphenol content in beer was increased from 246 to 457 mg/L. Finally, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging assays showed that the antioxidant and free radical scavenging capacities of high PA content beer were significantly improved compared with the control beer, suggesting the beneficial effects of PAs on flavor stability of beer.

Industrial Applications of Selected JFS Articles

Industrial Applications of Selected <i>JFS</i> Articles

Vitamin Fortification of Fluid Milk.

Vitamin concentrates with vitamins A and D are used for fortification of fluid milk. Although many of the degradation components of vitamins A and D have an important role in flavor/fragrance applications, they may also be source(s) of off-flavor(s) in vitamin fortified milk due to their heat, oxygen, and the light sensitivity. It is very important for the dairy industry to understand how vitamin concentrates can impact flavor and flavor stability of fluid milk. Currently, little research on vitamin degradation products can be found with respect to flavor contributions. In this review, the history, regulations, processing, and storage stability of vitamins in fluid milk are addressed along with some hypotheses for the role of vitamin A and D fortification on flavor and stability of fluid milk.

Advancing Flavor Stability Improvements in Different Beer Types Using Novel Electron Paramagnetic Resonance Area and Forced Beer Aging Methods

Three different electron paramagnetic resonance (EPR) metrics—lag time, T150, and area—were compared with sensory data from two forced beer aging methods. Three types of beers were evaluated, namely, 1) standard lager, 5% alcohol by volume (ABV) and 3.30° standard reference method (SRM) color; 2) low-alcohol lager, 3% ABV and 2.20° SRM color; and 3) standard ale, 5% ABV and 4.00° SRM color. The two accelerated aging time–temperature treatments evaluated in this study were 18 days at 27°C and six days at 40°C, both being equivalent sensory-wise to our standard flavor stability staling rate of six months at 20°C. A significant relationship between EPR area and sensory staleness scores was found using the 40°C for six days temperature abuse treatment protocol (R2 = 0.9209–0.9567), not the 27°C for 18 days abuse treatment protocol (R2 = 0.0319–0.2046). In addition, the area under the curve metric displayed significant correlation coefficients (R2 = 0.9209–0.9567) with the 40°C for six days abuse treatment staling scores, whereas the traditional lag time and T150 values were not significant (R2 = 0.0174–0.2238 and 0.1010–0.8565, respectively). Using this analytical and sensory chemoetricstyle approach, subsequent brewing materials and process changes were made in the brewing process to lower the EPR area values in five breweries spanning three years of profiling. This resulted in improved packaged beer flavor stability. Using the connection between these novel, rapid methods, this study also highlights three causative beer conditions that have traditionally shown major impacts on flavor stability: namely, trace metals (Cu and Fe), dissolved oxygen, and bisulfite (SO2) levels. Using the EPR area metric, which represents the total amount of free radicals generated during the beer sample analysis time, led the way to engage a rapid forced beer sensory method. Once employed, longer packaged beer shelf-life improvements over the three-year period were realized. This new dynamic program is currently being used in our breweries.