Removal Of Off-flavors Research Articles

Study on the effect of enzymolysis combined fermentation on reducing the off-flavor of egg white powder.

The application of egg white powder (EWP) was subject to its off-flavor. In the present study, flavourzyme and lactic acid bacteria were used to treat egg white powder (EWP) and the mechanism effects of enzymolysis-fermentation were explored. Compared with the control group, enzymolysis combined with fermentation treatment group (EW-EF) reduced the four-representative off-flavor compounds (geranyl acetone, 1-octen-3-ol, octanal and nonanal) by more than 62.66%. Fermentation produced esters with good flavor, and enzymolysis produced fresh amino acids. Characterization of protein structure indicated that fermentation decreased both fluorescence intensity and surface negative charges, accelerating the aggregation of proteins; enzymolysis promoted aggregation and degradation, improving the stability of the egg white proteins. Meanwhile, enzymolysis broke down the hydrophobic cavities bound to off-flavor compounds, releasing protein-bound off-flavor compounds and removing them through fermentation. EW-EF had the best effect of off-flavor removal on EWP. The results of the present study could provide a green and effective method for improving the flavor of EWP. © 2024 Society of Chemical Industry.

Composition of bacterial blends for fermentation-induced pea protein emulsion gels using multi-property screening of lactic acid bacteria

In this study, a comprehensive screening and identification process to pinpoint lactic acid bacteria (LAB) strains capable of enhancing gel firmness and elevating the flavor profile in pea protein-based protein gels was conducted, aiming to demonstrate how tailored starter cultures for specific applications can provide high-quality sensory attributes in fermented plant-based cheese. Thirteen single strains were selected from a poll of 90 different LAB based on their acidification performance, contribution to gel firmness, removal of off-flavors and production of dairy-associated volatile organic compounds. They were combined in 64 different blends of five strains each and screened again for the same parameters. Fast acidifying strains were prioritized for food preservation reasons to inhibit undesirable spoilage. Fermentation of pea protein emulsions with Streptococcus thermophilus, Lactobacillus, and Lactococcus blends resulted in a significant reduction in volatile organic compounds associated with beany and green off-flavor, a production of dairy-associated compounds, and satisfactorily contributed to gel firmness.

Effect of ozone and hydrogen peroxide on off-flavor compounds and water quality in a recirculating aquaculture system

The recirculating aquaculture system (RAS) is an ever-developing technology for producing fish with a low environmental impact. However, off-flavors can be a major problem in RAS fish production. Off-flavor compounds are of microbial origin and are accumulated in fish flesh. They typically cause a musty and earthy taste and odor, which consumers find unacceptable. Here we hypothesized that oxidizing compounds such as ozone (O3), hydrogen peroxide (H2O2), and their combinations, referred to as advanced oxidation processes (AOP)s, can remove or decrease these compounds in water and prevent their accumulation in fish. In this study, four different oxidative treatments (O3 low (0.4 mg O3 L−1), O3 high (0.8 mg O3 L−1), H2O2 (0.15 µl L−1), AOP (0.4 mg O3 L−1 & H2O2 0.10 µl L−1), and controls were applied to 10 experimental RASs for four months. The results showed that the treatments can reduce dissolved organic carbon (DOC) and the off-flavor compounds (geosmin, GSM and 2-methyl isoborneol, MIB) in circulating water, but they were not able to prevent the accumulated off-flavors in fish flesh below the sensory threshold. There was no significant difference in off-flavor removal between the treatments, which indicates that O3 treatment was ineffective in these conditions. However, H2O2 could still reduce the off-flavor concentrations in water.

Off-Flavor Removal from Sheep Placenta via Fermentation with Novel Yeast Strain Brettanomyces deamine kh3 Isolated from Traditional Apple Vinegar.

Animal placentae can be used as health-promoting food ingredients with various therapeutic efficacies, but their use is limited by their unpleasant odor and taste. This study aimed to investigate the possibility of deodorization of sheep placenta via yeast fermentation. A yeast strain was successfully isolated and identified as a novel Brettanomyces strain (Brettanomyces deamine kh3). The deodorizing efficacy of fermentation of the sheep placenta with B. deamine kh3 was evaluated by 42 panels, based on evaluation of preference, ranking, and aroma profiles, and compared with normal placenta and placenta fermented with B. bruxellensis. The results of the sensory evaluation indicated that fermentation of the sheep placenta with B. deamine kh3 may improve its palatability by increasing flavors such as that of grass (tree), rubber, and burnt, and by decreasing the odor and soy sauce flavor. Solid-phase microextraction-gas chromatography (SPME-GC) showed that major off-flavors in sheep placenta, such as ammonia, dimethyl disulfide, and 1,3-dioxolane, were completely diminished in the sheep placenta fermented with B. deamine kh3. This study presents those major volatile compounds, including 2-isobutyl\\-4,4-dimethyl-1,3-dioxane, and 3-methyl-1-butanol, could be crucial in improving the palatability of the sheep placentae fermented with B. deamine kh3. This study provides a good starting point for the industrial application of a new deodorization method.

Off-Flavor Removal from Sheep Placenta via Fermentation with Novel Yeast Strain Brettanomyces deamine kh3 isolated from Traditional Apple Vinegar

Off-Flavor Removal from Sheep Placenta via Fermentation with Novel Yeast Strain Brettanomyces deamine kh3 isolated from Traditional Apple Vinegar

Off-flavor removal from thermal-treated watermelon juice by adsorbent treatment with β-cyclodextrin, xanthan gum, carboxymethyl cellulose sodium, and sugar/acid

One of the most popular summer fruits is the watermelon, not only for its health benefits but also because of its high water content making it very refreshing. Watermelon therefore, is widely marketed in many forms. Industrial processing of the watermelon juice however, by thermal treatment develops an off-flavor which is not accepted by the consumers. In this study, XG, β-CD, CMC-Na, and SAR were selected to evaluate the removal effect to the off-flavor compounds in thermal treated watermelon juice. β-CD was found to be the most significant factor for increasing sensory score of TW, followed by the CMC-Na and SAR. T&β-CD reduced the concentration of decanal, octanol, (E)-2-octenol, and (E)-2-decenal by 50.82%, 22.81%, 36.43%, and 28.19%, respectively (p < 0.05). The intensity changes of SVP indicated the interaction of β-CD and octanol or (E)-2-decenal with the non-covalent bond by FT-IR. The peaks of octanol, (E)-2-decenal, and their β-CD chathrate in 13C NMR spectrogram suggested the combination of β-CD and these two volatile compounds. The study concluded that β-CD could remove the off-flavor compounds from heat treated watermelon juice effectively.

Effect of Ethanol and Temperature on Partition Coefficients of Ethyl Acetate, Isoamyl Acetate, and Isoamyl Alcohol: Instrumental and Predictive Investigation

For alcoholic beverages such as beer, downstream processing for either dealcoholization or off-flavor removal requires both quantitative data and suitable predictive methods. Along with experimental investigations, we use a method initially developed for studying the solubility of gases in two or more miscible liquid solvents to monitor the effect of ethanol on air–water partition coefficients of three major flavors found in beer, namely, isoamyl alcohol, ethyl acetate, and isoamyl acetate. In the ethanol concentration range between 0 and 0.1 mole fraction, a slight, rather linear increase in the Henry’s solubility coefficient was observed. This overall behavior can be captured well using Henry coefficients for aqueous binary and ternary systems together with the Wohl expansion for excess Gibbs free energy coupled with the one-parameter Margules equation. Based on the developed model, the Wohl’s expansion parameter for ethanol–water is introduced as the solvent–solvent interaction parameter. The van ’t Hoff parameters for temperature dependence of Henry coefficients for binary water–flavor solutions are determined in the range of 30 to 60 °C.

Effect of sodium chloride concentration on off-flavor removal correlated to glucosinolate degradation and red radish anthocyanin stability.

Anthocyanin-rich concentrates from different red radish can be used as natural food colorants. However, the development of off-flavor during extraction has been major challenge in processing industries. This work aimed to evaluate the effect of sodium chloride (NaCl) concentration in phosphoric acidified medium pH 2.5 on removal of off-flavor from red radish anthocyanin. The effect of NaCl concentration on anthocyanin properties was also evaluated. Results showed that the total glucosinolate was highly degraded at high NaCl concentration (< 500mM) compared with control, leading to higher off-flavor development. Additionally, the glucosinolate degradation was positively and significantly correlated to isothiocyanate, while was negatively and significantly correlated with dimethyl di-, trisulfide, cedrol, triacetin, 6-methyl-5-hepten-2-one. Moreover, total monomeric and color properties of extracted anthocyanins were degraded at high NaCl concentration (< 500mM) compared with control. The tentative anthocyanin identification by UPLC-TQ-MS showed 12 glycosylated anthocyanins substituted at C3 and C5 in tested anthocyanin extracts. In conclusion, higher NaCl concentration (< 500mM) could not be useful for red radish off-flavor removal and anthocyanin properties.

압출성형 무청 분말 추출물의 항산화 물질 함량 증가 및 이취 감소

Aerial parts (leaves and stems) of radish are usually discarded due to the distinct undesirable flavors associated with inappropriate preparations, despite their many health benefits. In this study, we examined the role of extrusion process in the removal of off-flavors and elevation of antioxidant activity in radish (Raphanus sativus L.) leaves and stems. To optimize the extrusion conditions, we changed the barrel temperature (110, 120, and 130°C), screw speed (150, 200, 250, and 300 rpm), and moisture content (20, 25, and 30%). The polyphenol and flavonoid contents significantly increased in extruded radish leaves and stems (ER) under optimum extrusion conditions (130°C, 250 rpm, and 20%). Under extrusion conditions, we compared off-flavors (as amount of sulfur-containing compound) levels between ER and non-extruded radish leaves and stems (NER) by an electronic nose. A total of six peaks (sulphur-containing compound) were similarly detected in both ER and NER, whereas the ER showed reduced off-flavors. Levels of glucosinolate (μg/g), which can be hydrolyzed into off-flavors during mastication or processing, were significantly decreased in the ER. From these results, extrusion processing can be an effective method to increase antioxidant activity and removal of off-flavors in radish leaves and stems.

Evaluation of depuration procedures to mitigate the off-flavor compounds geosmin and 2-methylisoborneol from Atlantic salmon Salmo salar raised to market-size in recirculating aquaculture systems

Fish cultured within water recirculating aquaculture systems (RAS) can acquire “earthy” or “musty” off-flavors due to bioaccumulation of the compounds geosmin and 2-methylisoborneol (MIB), respectively, which are produced by certain bacterial species present in RAS biosolids and microbial biofilms. Fish cultured in RAS are generally transferred to separate depuration systems that are flushed with water in a single pass or operated with limited water recirculation (with no biofilter), in order to purge these unpalatable flavors. Technologies and standard operating practices that optimize purging kinetics for Atlantic salmon Salmo salar and other species cultured in RAS are needed to improve the consistency and efficacy of depuration. A 2×2 factorial trial was conducted to evaluate techniques to mitigate off-flavor from Atlantic salmon cultured to 3–5kg in a semi-commercial scale freshwater RAS. Twelve replicated depuration systems (0.5m3) were used to evaluate four combinations (n=3) of the following standard operating procedure and system design parameters: (1) disinfection of depuration systems as a 1h static treatment using 250mg/L hydrogen peroxide (H2O2) prior to stocking fish, (2) no disinfection prior to stocking fish, (3) presence of water aeration media within gas transfer columns of depuration systems, and (4) absence of water aeration media within gas transfer columns of depuration systems. Food-size Atlantic salmon were stocked within the depuration systems and kept off feed for 10 days. Six salmon were harvested from the original RAS on Day 0 and fileted for baseline assessment of off-flavor concentrations. Thereafter, filet samples (n=3–4) were taken on Days 3, 6, and 10 to evaluate off-flavor kinetics. Hydrogen peroxide disinfection of depuration systems resulted in significantly reduced off-flavor in salmon filets during the depuration period. Results also indicated that the presence of high-surface-area water aeration media shielded biofilms from complete disinfection, resulting in less and slower off-flavor removal from Atlantic salmon filets; while depuration systems void of media resulted in greater and more rapid off-flavor reduction. Thus, water aeration media should not be used in depuration systems because of the challenges posed for effective cleaning, disinfection, and inactivation of off-flavor producing bacteria that may be present, and unit processes and locations that are difficult-to-clean should be excluded. In addition, a wide range of off-flavor concentrations were measured within individual salmon, indicating that one salmon is not a representative sample size to determine market suitability.

Earthy and Fresh Mushroom Off-Flavors in Wine: Optimized Remedial Treatments

Geosmin and 1-octen-3-one are the causal agents of earthy-muddy and fresh mushroom off-flavors. Several products are available to remove these off-flavors and are commonly used at different steps of winemaking for various applications. This research evaluated and compared the efficiencies of those commercial products, including activated carbons, chitosans, zeolites, and filtrations, on white wine. For each product, different doses were evaluated on wine spiked at 200 ng/L of geosmin or 1-octen-3-one and were measured by GC-MS/MS. Several formulations of activated carbon provided good efficiencies for geosmin removal, as well as a filtration dedicated to off-flavor removal. However, chitosans and zeolites generally did not reach a satisfactory level. Activated carbons were also able to reduce the concentration of 1-octen-3-one.

Removal of off-flavors from sea tangle (Laminaria japonica) extract by fermentation with Aspergillus oryzae

This study was conducted to reduce off-flavors from sea tangle (Laminaria japonica) extract since the typical odor of seaweed is an impediment to consumption of seaweed products. Fifty-six odor compounds emitted from the extract were identified using a thermal desorbor and gas chromatography–mass spectrometry. On the basis of expected odor intensity (EOI), isovaleric acid (41.2%), allyl isothiocyanate (22.6%), octanal (11.1%) and acetaldehyde (10.6%) were responsible for about 85.5% of total odor strength in the extract, suggesting that the odor of the extract might mainly be attributed to these compounds. The EOIs of odor compounds were dramatically reduced or disappeared during fermentation by Aspergillus oryzae. Total EOI of the odor compounds decreased about four-fold, compared with that of the raw extract (control) after the four days of fermentation at 30°C with agitation at 120rpm. These results indicate that microbial fermentation may be a good strategy to reduce off-flavors of seaweeds.

Removal of off-flavors and isolation of fatty acids from boiled anchovies using supercritical carbon dioxide

Herein, we extracted boiled anchovies with supercritical carbon dioxide (SCO2) at various temperatures (40 to 50°C) and pressures (7.7 to 35 MPa), which successfully removed trimethylamine and dimethyl disulfide, the main odorous compounds that produce off-flavors in fish. We extracted the following fatty acids from boiled anchovies: myristic acid, palmitic acid, stearic acid, palmitoleic acid, EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). In addition, we observed a higher concentration of polyunsaturated fatty acids (PUFAs), such as EPA and DHA, in SCO2-extracted anchovy oil than in organic solvent-extracted oil.

Enzymatic Removal of Off-flavors from Apple Juice

Contaminating microorganisms such as Actinomycetes, Alicyclobacillus, and Chlostridium can generate off-flavors in apple juices. Such bacterial metabolites represent, besides phenol types such as guaiacol and 2,6-dibromophenol, a broad range of other chemicals, for example, geosmin, 2-methylisoborneol, or alpha-terpineol. A laccase from Trametes hirsuta was purified, immobilized, and applied for the selective elimination of off-flavor substances in apple juice caused by microbial contamination. The evaluation using GC-MS showed that enzymatic treatment could reduce the amount of guaiacol and 2,6-dibromophenol in apple juice significantly by 99 and 52%, respectively. Upon addition of mediators, the degradation could be increased and the spectrum of substrates extented. Furthermore, commercial apple juices spiked with off-flavors were treated in a continuous-flow reactor and tested by sensory evaluation.

Evaluation of Acid and Alkaline Processing to Remove Muddy Off-Flavors in Channel Catfish (Ictalurus punctatus)

ABSTRACT Conditions that optimize 2-methylisoborneol (MIB) and geosmin reduction by protein solubilization were evaluated in channel catfish. For both MIB and geosmin spiked fish, acid and alkaline solubilizations effectively (p < 0.001) reduced off-flavor. Average MIB and geosmin levels for untreated, unprocessed fish were 1.396 and 1.992 ppb, respectively. Pooled centrifuge levels for treated fish were: 0.194 ppb MIB and 0.398 ppb geosmin using citric acid; 0.104 ppb MIB and 0.258 ppb geosmin using phosphoric acid; 0.143 ppb MIB and 0.543 ppb geosmin using acetic acid; and 0.0987 ppb MIB and 0.426 ppb geosmin using alkaline (sodium hydroxide) conditions. Centrifugation did not significantly affect (p = 0.999) off-flavor removal for MIB, however it did significantly affect (p = 0.05) geosmin removal.

GAC adsorber design protocol for the removal of off-flavors

This paper investigates the effectiveness of granular activated carbon (GAC) for removing off-flavor compounds of water—geosmin and 2-methylisoborneol (MIB). More specifically, it focuses on the development of an appropriate modeling approach and experimental protocol for the design of fixed-bed GAC adsorbers. Adsorption equilibrium, rate and long-term mini-column studies were conducted on a bench-scale for geosmin and MIB to estimate the equilibrium and mass-transfer parameters required for adsorber modeling. The dispersed flow homogeneous surface diffusion model (DFHSDM) was used for the prediction/simulation of the adsorber dynamics. Scale-up procedures based on dimensional analysis and similitude were employed for the design of full-scale adsorbers from bench-scale adsorbers, and for performance forecasting of full-scale adsorbers under different operating conditions. More importantly, operation and maintenance (O & M) costs were estimated for full-scale adsorbers directed at the removal of off flavor compounds, based on carbon utilization rates and disposal costs. These estimates were obtained for different plant capacities and empty bed contact times (EBCTs).

Legume lipids.

The storage lipids of legume seeds are a major source of dietary fat. As a result of their importance in the food industry, much is known about lipid composition, chemistry, flavor, off-flavor development, and their technological implications in foods of dry, oil-rich seeds such as soybeans and peanuts. Lipids from green pea have also been investigated to some extent. Other food legume lipids have not been studied in any great detail because of their low lipid content and limited or negligible use for oil purposes. Literature on the biochemical, nutritional, and toxicological aspects of lipids from these other legumes is scanty, compared to published reports of seed lipids from soybean and peanuts. Lipids of soybean, peanut, and green pea are reported in this article. Their chemistry, interactions with other constituents, role in flavor development, as well as alterations due to processing and removal of off-flavors are reviewed. The nutritional and toxicological implications of legume lipids from soybean, peanuts, and other food legumes are also discussed.

Comparison of American and foreign clays as paper fillers

Fish cultured within water recirculating aquaculture systems (RAS) can acquire “earthy” or “musty” off-flavors due to bioaccumulation of the compounds geosmin and 2-methylisoborneol (MIB), respectively, which are produced by certain bacterial species present in RAS biosolids and microbial biofilms. Fish cultured in RAS are generally transferred to separate depuration systems that are flushed with water in a single pass or operated with limited water recirculation (with no biofilter), in order to purge these unpalatable flavors. Technologies and standard operating practices that optimize purging kinetics for Atlantic salmon Salmo salar and other species cultured in RAS are needed to improve the consistency and efficacy of depuration. A 2 × 2 factorial trial was conducted to evaluate techniques to mitigate off-flavor from Atlantic salmon cultured to 3–5 kg in a semi-commercial scale freshwater RAS. Twelve replicated depuration systems (0.5 m3) were used to evaluate four combinations (n = 3) of the following standard operating procedure and system design parameters: (1) disinfection of depuration systems as a 1 h static treatment using 250 mg/L hydrogen peroxide (H2O2) prior to stocking fish, (2) no disinfection prior to stocking fish, (3) presence of water aeration media within gas transfer columns of depuration systems, and (4) absence of water aeration media within gas transfer columns of depuration systems. Food-size Atlantic salmon were stocked within the depuration systems and kept off feed for 10 days. Six salmon were harvested from the original RAS on Day 0 and fileted for baseline assessment of off-flavor concentrations. Thereafter, filet samples (n = 3–4) were taken on Days 3, 6, and 10 to evaluate off-flavor kinetics. Hydrogen peroxide disinfection of depuration systems resulted in significantly reduced off-flavor in salmon filets during the depuration period. Results also indicated that the presence of high-surface-area water aeration media shielded biofilms from complete disinfection, resulting in less and slower off-flavor removal from Atlantic salmon filets; while depuration systems void of media resulted in greater and more rapid off-flavor reduction. Thus, water aeration media should not be used in depuration systems because of the challenges posed for effective cleaning, disinfection, and inactivation of off-flavor producing bacteria that may be present, and unit processes and locations that are difficult-to-clean should be excluded. In addition, a wide range of off-flavor concentrations were measured within individual salmon, indicating that one salmon is not a representative sample size to determine market suitability.