This study investigated the effect of the oak chips added at different dosages and stages of apple wine production on its oenological, antioxidant and sensory properties. In the study, medium-toasted ...or heavily-toasted oak chips (at a concentration of 3 or 6 g/L) and ethanol extracts prepared from them (at a dose of 1 or 2 mL/100 mL) were used. Basic oenological parameters (OIV), total polyphenol content (Folin-Ciocalteu method), antioxidant activity (ABTS assay), color (CIELAB) and organoleptic assessment of the wine were evaluated. Although the use of chips had no significant effect on the ethanol content and wine extract, it caused a significant change in volatile acidity. Furthermore, the antioxidant activity of the wines correlated closely with the concentration of polyphenolic compounds and these parameters were significantly higher after contact with medium-toasted chips. The apple wines had high values of lightness and yellow color, and the addition of chips did not significantly affect the color parameters (CIELAB). In the sensory assessment, the control wine (without chips) received the lowest scores, while significantly higher scores were given to the wine with the addition of 6 g/L of heavily-toasted chips, which was characterized by intense smoky, toasty, woody and vanilla notes.
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•PME, PL and PG were inhibited but not totally inactivated in apple wine fermentation.•CaCl2 promoted methanol yield and pectin breaking by promoting PME and PL activities.•PME, PL ...and PG were activated and methanol increased after aging at 4 °C for 30 days.•CaCl2 retained pectin with Mp of 3.07 kDa, which was degraded mostly in wine I.•Pectin’s Mp in group S was split into molecular mass lower than 3 kDa.
Understanding pectin structure and pectinase activity was important to control methanol content in apple wine. Therefore, this study compared inoculated fermentation (I), spontaneous fermentation (S) and inoculated fermentation combined with CaCl2 treatment (I & CaCl2) to explore their differences in methanol production, pectin peak molecular weight (Mp), and the activities of pectin methyl esterase (PME), pectin lyase (PL) and polygalacturonase (PG). The results showed that the activities of PME, PL and PG were intensively inhibited during fermentation; however, they still retained 3.41–5.84% (PME), 9.46–17.71% (PL) and 9.17–10.31% (PG) of the initial activities after aging for 30 days. Therefore, the methanol content was increased in all three aged wines even aging at 4 °C. CaCl2 promoted the PME and PL activities, and thus accelerated the methanol production. Because the pectin with Mp 3.07 kDa was retained by CaCl2, the highest pectin content was found in wine I & CaCl2 (160.69 mg/L), which was 95.47 mg/L higher than that in wine I, and 107.03 mg/L higher than that in wine S. In group S, the long lag period allowed pectin to withstand the pectinases inherent in apple juice for a long time, which was conducive to the cleavage of pectin to Mp lower than 3 kDa continuously, its further degradation led to the lowest pectin content (53.65 mg/L) in wine. Hence, inhibiting the pectinases activities, or shortening the aging period would play an important role in decreasing the methanol content in apple wine.
This work reports the evolution of polyphenolic compounds content during the cidermaking process in the Basque Country (Northern Spain). Fourteen monovarietal musts were obtained throughout three ...seasons (13 different, one repeated) using different apple cultivars from the Basque Country. Monovarietal musts were used to cover a wide range of polyphenolic content and to introduce variability. These musts were fermented and matured to obtain 14 monovarietal ciders. The evolution of the musts was monitored during 6–8 months by measuring the polyphenolic profile with an HPLC method throughout 4 or 5 samplings. Chlorogenic acid, 4-p-coumaroylquinic acid and (−)-epicatechin showed fluctuations during the alcoholic fermentation (10–40 days), followed by stabilisation. With phloretin 2′-O-xyloglucoside, an increase or a stable concentration was observed during the alcoholic fermentation followed by stabilisation. Tyrosol, absent in the initial musts, showed an increase during the alcoholic fermentation and became stable afterwards. These were the only general patterns observed. The rest of the phenolic compounds studied, such as procyanidin B1, procyanidin B2 and phloridzin, did not show any general evolution rule.
•The chlorogenic acid content remained stable after alcoholic fermentation.•4-p-Coumaroylquinic acid and (−)-epicatechin showed the same behaviour.•Tyrosol was produced during alcoholic fermentation and became stable afterwards.•Procyanidin B1, procyanidin B2 and phloridzin, did not show any general pattern.
To explore the effects of storage on the organic acids and volatiles in apple wine, fresh Fuji and Ralls Genet apples were stored for 5 months and making apple wines monthly. By 5-month storage, ...L-malic and succinic acids in juices decreased by 1755.78–2269.69 mg/L and 582.25–943.10 mg/L, respectively. Correspondingly, l-malic acid decreased by 665.73–987.45 mg/L in wine. Succinic acid from fermentation was positively correlated with the pH of juices (r = 0.709*). Storage enriched fruit volatiles, especially in Ralls Genet, 6 volatiles were generated by 1 month storage. Isobutylacetate, isoamylacetate and hexylacetate were mostly affected in Fuji juice; they were increased by 32.80, 20.54 and 7.99 times by 3 months storage. While isoamylol, 1-hexanol and 6-methyl-5-hepten-2-ol in Ralls Genet juice rose up by 11.43, 3.92 and 137.37 times during storage. Esters were mostly affected by storage in apple wines, especially Fuji wine, its content decreased by 59.4–104.05 mg/L after 5 months storage. The production of volatiles in Ralls Genet wine was more easily affected by pH of juice. Therefore, apple storage affected organic acids and volatiles in apple wines by affecting apples and yeast metabolism simultaneously. And apple stored for 1 month achieved balanced taste and richness flavors.
•The increase of juice pH affected the metabolism of organic acids.•Over 95% citric acid in wine was produced by fermentation and affected wine pH.•Esters in Fuji juice and alcohols in Ralls Genet were mostly affected by storage.•Volatiles in Ralls Genet wine were more easily affected by the juice pH.•Storage generated 6 volatiles in Ralls Genet juice, but only 1 in Fuji juice.
•pH 3.0 regulated by malic acid inhibited 95.8–96.6 % of juice’s PME activity.•Bentonite treatment decreased pectin and PME activity of apple juice simultaneously.•PME increased with the increasing ...of pH during fermentation in malic acid treatment.•Long fermentation period at 10 °C led to a higher methanol content than that at 20 °C.•The lowest pectin and PME led to the lowest methanol by bentonite treatment.
To elucidate the effect of bentonite and pH of apple juice on pectin methyl esterase (PME) activity and methanol content, apple juice was treated with bentonite and malic acid and incubated for 24.0 h at 20 °C and 10 °C, respectively. The treated juice was fermented at 20 °C and 10 °C, respectively. Results showed that bentonite absorbed 28.9–31.5 % of pectin and reduced 56 % of PME activity in apple juice. Whereas pH 3.0 regulated by malic acid inhibited 95.8–96.6 % of PME activity and the activity increased during fermentation owing to the increase of pH. Consequently, the lowest pectin and PME activity caused methanol content to decrease by 33.4–34.3 % in bentonite treated apple wine; while a lower PME activity caused methanol content to decrease by 11.9 % in malic acid treated fermented apple juice. A longer fermentation period at 10 °C led to a higher methanol content than that at 20 °C. Structural equation model indicated that the methanol content was directly affected by pectin in the three treatments. Whereas the PME activity directly affected the methanol content in malic acid treatment at 10 °C.
•Glutathione (GSH) can protect certain mono-phenols and reduce the color index of apple wine.•GSH changed the profile of mono-phenols.•GSH acted as a modifier of volatile aromas.•Apple wine with ...different GSH additions could be distinguished by e-nose.
To investigate the effect of reduced glutathione (GSH) on the quality characteristics of apple wine, 10, 20 and 30 mg/L of GSH were added to apple juice before alcoholic fermentation. Meanwhile, apple wine fermented by Saccharomyces cerevisiae which had been pre-incubated with GSH (100 mg/L) was another experimental group. Mono-phenols, GSH and oxidized glutathione (GSSG) were determined by HPLC. Aroma compounds were analysed by GC–MS. Further, E-nose was applied to monitor the odor. After fermentation, GSH content was the same in all of the samples. However, for the apple wine with GSH addition, GSSG content increased significantly. Notably, GSH could reduce the color index, protect chlorogenic acid and phloretin, decrease the content of epicatechin and catechin as well as change the profile of aroma compounds (higher levels of 2-methyl-1-propanol, 3-methyl-1-butanol, ethyl benzoate, linalool, etc.). GSH may be used for flavor enhancement and quality improvement of apple wine.
Progressive freeze-concentration (PFC) by a tubular ice system was successfully applied to concentrate apple juice from 13.7 to 25.5 oBrix under a program controlled operation for the coolant ...temperature and the circulation pumping speed. The organic acid distribution and the flavor profile analysis revealed that no substantial differences were observed for the juice before and after concentration both in organic acids and flavor components showing the high quality concentration by PFC. This was also confirmed by electronic taste and flavor analyzers. The PFC-concentrated apple juice was fermented to obtain a new type apple wine with alcohol content as high as 13.7 vol-% without chaptalization. The organic acid distribution was slightly changed before and after fermentation while the flavor profile changed drastically. The present technique will be applicable to produce new type of wine from many other fruits.
•Apple juice was concentrated up to 25.5 oBrix by progressive freeze-concentration.•Organic acid and flavor profiles were almost completely retained after concentration.•Concentrated juice was fermented to obtain apple wine with 13.7 vol-% alcohol.
Pond apple (Annona glabra L.) trees were widely distributed in swamp regions of Mekong Delta, Vietnam. Pond apple fruits turned from green to yellow when ripening. Ripen pond apple fruits contained ...numerous phenolic constituents with valuable phytochemical benefits. However, ripen pond apple fruits were not successfully utilized as other commercial fruits. This research examined the possibility of wine production utilized from ripen pond apple fruits. Different various technical variables of fermentation affecting to the quality of pond apple wine were thoroughly examined. Ripen pond apple fruits were naturally collected from Soc Trang province, Vietnam. Ripen pond apple fruits were peeled, blended, deseeded, crushed, enzyme-treated (pectinase 25 mg/L), added with sugar (5-13% w/w), pasteurized (sulphite 30 mg/L), inoculated with yeast Saccharomyces pastorianus ratio (0.1-0.5%), macerated temperature (14-22oC) in different time (6-14 days). Malolactic fermentation was performed in anaerobic condition at 12oC in different durations (4-20 weeks). At the end of malolactic fermentation, wine was racked and clarified with different fining agents (bentonite, polyvinylpyrrolidone, wheat gluten, gelatin, kaolin) at 0.03% (v/v). Results showed that must should be added with 9% sugar and 0.4% yeast inoculation, fermentation temperature of 16oC in 10 days. Malolactic fermentation could be terminated at 12 weeks. Gelatin revealed the best candidate among different clarifying agents to remove turbidity in pond apple wine while retaining the most total phenolic content and antioxidant capacity. Under above technical variable conditions, fermentation gave the high ethanol content (4.26±0.02 % v/v); the total phenolic content (32.79±0.00 mg GAE/100 ml), 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging (11.84±0.01 %), overall acceptance (8.34±0.01 score) meanwhile low turbidity (24.41±0.00 NTU) was also noticed. High ethanol content and phytochemical retention contributed to the high sensory score of pond apple wine. These quality parameters were acceptable for an alcoholic drink. Ripen pond apple fruit would be a promising carbohydrate source to convert into a new fruit wine with a pleasant alcoholic flavor and attractive appearance.
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