The neutral volatile components of cider apple juices

Examination of the volatile compounds from juices of four cultivars of cider apple (‘Bramley's Seedling’, ‘Sweet Coppin’, ‘Kingston Black’ and ‘Yarlington Mill’) has led to the definite identification of eighteen alcohols, forty-eight esters, five carbonyls, eight acetals, four ethers, one lactone, one hydrocarbon and three halogenated compounds, tentative evidence being presented for a further 51 components. Fifty-five of the reported compounds have not previously been found in whole apples or juices. Of these cis and trans linalool oxide and the presence of 5-hexen-1-ol, rather than 2-hexen-1-ol, in the juice of the cultivar ‘Kingston Black’, are of particular interest. Differences between cultivars were largely quantitative and due to variations in the amounts of components with boiling points in excess of that of hexanol.     

Changes in the odors of reconstituted apple juice during thermal processing

Influences of the thermal treatment on the odors of apple juice were investigated by sensory methodology. Reconstituted juice was treated at 80, 90, 100, 110 and 120 °C for 2.0∼320 s by a continuous-flow thermal treatment. Treated juices were subjected to a series of sensory evaluations. The odors of apple juice changed markedly with the treatment temperature and residence time. The quality optimum points were observed around 65 s for 80 °C, 25 s for 90 °C and 15 s for 100 °C. Points of subjective equality on the thermal degradation of apple juice odor were also estimated. Present data enabled the thermal treatment of reconstituted apple juice to be optimized.     

Dissolved oxygen content in apple must: technological implications in cider processing

Oxygen can influence the composition and quality of apple must and cider. In this study, the effect of unit operations on oxygen dissolution during apple must processing was investigated and the technological implications discussed. Oxygen dissolution after different apple must processing unit operations, and also the effect of enzymatic browning reaction on dissolved oxygen uptake were analysed. During pressing, the highest and first oxygen dissolution occurred in the must at 6.8 mg/L, on average. The enzymatic browning reaction after 10 min was responsible for an oxygen uptake above 80%. The addition of sulphur dioxide or maceration of crushed apple results in a must with more oxygen content, however the beverage colour is negatively affected. The incorporation of oxygen into the must by bubbling oxygen or the movement of liquid may not be effective owing to consumption by the reaction of residual polyphenol oxidase. Moreover, this can affect the alcoholic fermentation because of the oxidation of nutrients such as vitamins. If the apple must is depectinized, racked and filtered, there will be enough oxygen to obtain a quality cider. These results and observations can be useful for selecting unit operations in cider companies in order to improve the beverage quality. Copyright © 2014 The Institute of Brewing & Distilling     

利用浓缩苹果汁生产苹果干酒工艺研究

以浓缩苹果汁为原料,利用单因素实验和正交实验对全汁型苹果干酒的发酵条件进行了优化.同时研究了不同发酵条件下,苹果汁中的糖、酸、酒精度的变化趋势.结果表明:利用浓缩苹果汁酿制苹果干酒的最佳工艺条件为:温度20℃、酸度pH3.6、糖度23％、酵母菌种为活性干酵母.在此条件下发酵得到的产品,其感官评定平均分数达到92.5分.     

利用浓缩苹果汁生产苹果干酒工艺研究

以浓缩苹果汁为原料,利用单因素实验和正交实验对全汁型苹果干酒的发酵条件进行了优化。同时研究了不同发酵条件下,苹果汁中的糖、酸、酒精度的变化趋势。结果表明:利用浓缩苹果汁酿制苹果干酒的最佳工艺条件为:温度20℃、酸度pH3.6、糖度23%、酵母菌种为活性干酵母。在此条件下发酵得到的产品,其感官评定平均分数达到92.5分。      

Apple quality,storage, and washing treatments affect patulin levels in apple cider

Patulin is a mycotoxin produced primarily by Penicillium expansum, a mold responsible for rot in apples and other fruits. The growth of this fungus and the production of patulin are common in fruit that has been damaged. However, patulin can be detected in visibly sound fruit. The purpose of this project was to determine how apple quality, storage, and washing treatments affect patulin levels in apple cider. Patulin was not detected in cider pressed from fresh tree-picked apples (seven cultivars) but was found at levels of 40.2 to 374 microg/liter in cider pressed from four cultivars of fresh ground-harvested (dropped) apples. Patulin was not detected in cider pressed from culled tree-picked apples stored for 4 to 6 weeks at 0 to 2 degrees C but was found at levels of 0.97 to 64.0 microg/liter in cider pressed from unculled fruit stored under the same conditions. Cider from controlled-atmosphere-stored apples that were culled before pressing contained 0 to 15.1 microg of patulin per liter, while cider made from unculled fruit contained 59.9 to 120.5 microg of patulin per liter. The washing of ground-harvested apples before pressing reduced patulin levels in cider by 10 to 100%, depending on the initial patulin levels and the type of wash solution used. These results indicate that patulin is a good indicator of the quality of the apples used to manufacture cider. The avoidance of ground-harvested apples and the careful culling of apples before pressing are good methods for reducing patulin levels in cider.     

Isolation and characterization of Escherichia coli recovered from Maryland apple cider and the cider production environment

Contaminated apple cider has been implicated in several Escherichia coli O157:H7 outbreaks. In an attempt to investigate sources and modes of entry of E. coli into apple cider, samples of fresh apple, pomace, and cider and equipment and mill floor swabs were analyzed for standard plate counts (SPC), total coliforms (TC), fecal coliforms (FC), and E. coli. E. coli was isolated from 14 (33%) of 42 samples of bottled fresh cider, from food equipment in 6 (67%) of 9 mills, and from apples, pomace, or cider in 7 (78%) of 9 mills. Seventy-five E. coli isolates were further characterized for Shiga toxin-producing E. coli (STEC)-associated virulence factors, antimicrobial susceptibility, and pulsed-field gel electrophoresis (PFGE) type. No E. coli O157:H7 or other STEC was identified. Serotyping and PFGE revealed 64 distinct profiles, suggesting that recovered E. coli arose from multiple independent sources. However, on one occasion, E. coli isolated from the source apple sample was closely related to the E. coli identified in the finished cider sample. E. coli isolates were further tested for antimicrobial susceptibility to 17 antimicrobial agents of human and veterinary importance. Fourteen (19%) of the 75 isolates were resistant to at least one of the antimicrobial agents tested, and 9 (12%) were resistant to at least two of these agents. Of the resistant isolates recovered, 64% were resistant to tetracycline and 57% were resistant to streptomycin. Overall, the level of E. coli contamination in source apple samples did not differ significantly from those in samples of pomace, cider at the press, and cider entering the bottling tank; therefore, source apples cannot be dismissed as a potential contributor of E. coli to the cider-making process.     

UV inactivation of bacteria in apple cider

Apple cider, inoculated with Escherichia coli and Listeria innocua, was processed using a simple UV apparatus. The apparatus consisted of a low-pressure mercury lamp surrounded by a coil of UV transparent tubing. Cider was pumped through the tubing at flow rates of 27 to 83 ml/min. The population of E. coli K-12 was reduced by 3.4 +/- 0.3 log after being exposed for 19 s at a treatment temperature of 25 degrees C. The population of L. innocua, which was more resistant to UV, was reduced by 2.5 +/- 0.1 log after being exposed for 58 s. The electrical energy for the process was 34 J/ml and is similar to that for conventional thermal processing. UV processing has the potential to improve the safety and extend the shelf life of apple cider.     

全汁干型苹果酒的生产工艺研究

通过研究不同的发酵工艺对成品酒的得率,酒的风味及酒的稳定性的影响,认为澄清汁发酵工艺适宜于酿制全汁干型苹果酒;通过对不同酵母进行发酵工艺对比研究,选定低温纯酵母发酵工艺,很好地保存了果香,酒体细致;通过采用高新生物技术－－复合果胶酶澄清工艺及硅藻土－纸板－膜过滤技术,解决了国内同类酒中普遍存在的稳定性欠佳的问题。此外还通过天然色素调色试验选出了适宜于干红酒着色的葡萄紫色素,解决了红酒色泽过淡的问题     

Patulin reduction in apple juice from concentrate by UV radiation and comparison of kinetic degradation models between apple juice and apple cider

Patulin, a mycotoxin produced by several genera of fungi, including Byssochlamys, Aspergillus, and Penicillium, has been an important concern in apple cider and apple juice due to its toxicity and health consequences. In this study, the effects of UV on the patulin level, physical and chemical properties, and sensory attributes in apple juice from concentrate were investigated. Kinetic modeling of patulin reduction by UV radiation in apple juice from concentrate was calculated and compared with the degradation rate observed previously in apple cider. From an initial patulin contamination of approximately 1,000 ppb (μg/liter), the UV exposure, ranging from 14.2 mJ/cm(2) (one pass) to 99.4 mJ/cm(2) (seven passes), was successful in reducing patulin levels by 72.57% ± 2.76% to 5.14% ± 0.70%, respectively. Patulin reduction by UV radiation followed first-order kinetic modeling in a fashion similar to first-order microbial inactivation. An exponential correlation between UV exposure and the percentage of patulin remaining was observed, giving an r(2) value of 0.9950. Apple juice was repeatedly exposed to 14.2 mJ/cm(2) for each treatment, and patulin levels were significantly decreased when compared with the level obtained with the previous UV exposure treatment. While there were no significant differences in the percentages of titratable acidity and ascorbic acid (P > 0.05), there were minor yet random sampling differences in pH and degrees Brix (1 °Brix is 1 g of sucrose in 100 g of solution; the °Brix represents the soluble solids content of the solution as percentage by weight [%, wt/wt]) (P ≤ 0.05). A significant difference (P ≤ 0.05) in sensory perception for the finished apple juice was detected between the control and the full seven-pass UV radiation treatment using an experienced consumer panel and a triangle test. Patulin reduction by UV radiation from both the current study and a previous study involving apple cider was compared, which showed that both matrices strongly fit a first-order kinetic degradation model. However, the kinetic constant for degradation in apple juice was approximately 5.5 times greater than that observed in an apple cider matrix.     

两种苹果(等外果)汁贮藏期间挥发性成分变化

为了探讨贮藏时间对苹果(等外果)汁挥发性成分的影响,采用静态顶空固相微萃取-气相色谱-质谱联用技术,分别分析富士和秦冠2个品种(等外果)苹果汁在25℃贮藏1、2、4、8和16周时挥发性成分的组成,对苹果汁中5类37种挥发性成分进行了定量分析,主要包括:酯类、醇类、醛类、酮类和酸类化合物。测定结果表明,富士和秦冠(等外果)苹果汁中主要挥发性成分包括:丁酸乙酯、2-甲基丁酸乙酯、乙酸丁酯、乙酸己酯、丁酸己酯、乙酸戊酯、1-丁醇、3-甲基-1-丁醇、正己醇、己醛、(E)-2-己烯醛、β-大马酮和香叶基丙酮,两种苹果汁贮藏16周后挥发性成分的保留率在87%以上,酯类、醇类和酮类挥发性成分呈下降趋势,醛类成分上升趋势明显,2种苹果汁中单一挥发性组分呈现不同的变化规律。此结果可为苹果(等外果)汁的挥发性成分利用和品质控制提供科学依据。     

Polyphenol oxidase activity as a potential intrinsic index of adequate thermal pasteurization of apple cider

In response to increasing concerns about microbial safety of apple cider, the U.S. Food and Drug Administration has mandated treatment of cider sufficient for a 5-log reduction of the target pathogen. Pasteurization has been suggested as the treatment most likely to achieve a 5-log reduction, with Escherichia coli O157:H7 as the target pathogen. Regulators and processors need a reliable method for verifying pasteurization, and apple cider polyphenol oxidase (PPO) activity was studied as a potential intrinsic index for thermal pasteurization. The effect of pasteurization conditions and apple cider properties on PPO activity and survival of three pathogens (E. coli O157:H7, Salmonella, and Listeria monocytogenes) was studied using a Box-Behnken response surface design. Factors considered in the design were pasteurization conditions, i.e., hold temperature (60, 68, and 76 degrees C), preheat time (10, 20, 30 s), and hold time (0, 15, 30 s), pH, and sugar content ((o)Brix) of apple cider. Response surface contour plots were constructed to illustrate the effect of these factors on PPO activity and pathogen survival. Reduction in PPO activity of at least 50% was equivalent to a 5-log reduction in E. coli O157:H7 or L. monocytogenes for cider at pH 3.7 and 12.5 (o)Brix. Further studies, however, are needed to verify the relationship between PPO activity and pathogen reduction in cider with various pH and (o)Brix values.     

Changes in volatile composition and sensory attributes of wines during alcohol content reduction

A desirable sensory profile is a major consumer driver for wine acceptability and should be considered during the production of reduced‐alcohol wines. Although various viticultural practices and microbiological approaches show promising results, separation technologies such as membrane filtration, in particular reverse osmosis and evaporative perstraction, in addition to vacuum distillation, represent the most common commercial methods used to produce reduced‐alcohol wine. However, ethanol removal from wine can result in a significant loss of volatile compounds such as esters (ethyl octanoate, ethyl acetate, isoamyl acetate) that contribute positively to the overall perceived aroma. These losses can potentially reduce the acceptability of the wine to consumers and decrease their willingness to purchase wines that have had their alcohol level reduced. The change in aroma as a result of the ethanol removal processes is influenced by a number of factors: the type of alcohol reduction process; the chemical‐physical properties (volatility, hydrophobicity, steric hindrance) of the aroma compounds; the retention properties of the wine non‐volatile matrix; and the ethanol level. This review identifies and summarises possible deleterious influences of the dealcoholisation process and describes best practice strategies to maintain the original wine composition. © 2016 Society of Chemical Industry     

甬优15在储藏期间挥发性成分的变化

通过HS-SPME/GC-MS技术,对不同含水量以及储藏时间的甬优15优质稻的挥发性成分进行分析,结果表明:随着储藏时间的延长,烯烃类、醇类、醛类物质的含量呈上升趋势,酮类和酯类变化不明显,烷烃类和酸类呈下降趋势。含水量14.5%的甬优15的清香物质含量高于13.1%和13.8%含水量的甬优15;当储藏180 d时,很多清香物质的含量达到峰值,继续储藏清香物质含量降低,储藏效果变差。1-壬醇随着储藏时间延长呈上升趋势,可作为甬优15储藏时间延长的醇类标志物;邻苯二甲酸二异丁酯的含量随着储藏时间的延长先下降后上升再下降,可作为甬优15的酯类标志物;反式-2-壬烯醛的含量随着储藏时间先上升后降低,且含水量越高,其含量越高,可作为甬优15的醛类标志物。关键字     

Power ultrasound treatment of Listeria monocytogenes in apple cider

Inactivation experiments with Listeria monocytogenes 10403S, an ultrasound-resistant strain, were conducted at sublethal (20, 30, and 40 degrees C) and lethal (50, 55, and 60 degrees C) temperatures in saline solution (pH 7.0), acidified saline solution (pH 3.4), and apple cider (pH 3.4) with and without application of ultrasound (20 kHz, 457 mW.ml(-l)). The survival of recoverable L. monocytogenes 10403S in apple cider was evaluated, and the effects of temperature, ultrasound, pH, and food matrix on inactivation were studied. Application of ultrasound increased the inactivation rate at both sublethal and lethal temperatures. Additional death of L. monocytogenes 10403S was due to low acidity at the lethal temperatures. The reduction in surviving L. monocytogenes 10403S followed first order kinetics at sublethal temperatures, but at lethal temperatures, a two-section linear model described the inactivation behavior. The bactericidal effect of thermosonication was additive in apple cider. The survival tests of L. monocytogenes 10403S in apple cider indicated the possibility of using a mild treatment condition in combination with ultrasound to achieve a 5-log reduction in number of listerial cells.     

Quality attributes of frozen okra as influenced by processing and storage

Sensory evaluation and chemical analyses were carried out on unblanched, steam-blanched (5 min, 100°C) and water-blanched (3 min, 98°C) okra held in frozen storage (–18°C) for 4, 8, 12 and 32 weeks. Hot water-blanched frozen okra compared favourably with fresh samples, even after 32 weeks, in colour, flavour and overall acceptability and was superior to steam-blanched and unblanched except in viscosity. Blanching, especially in steam, improved ascorbic acid retention during frozen storage. Little change in protein occurred.     

Potential sources of microbial contamination in unpasteurized apple cider

A study was conducted to identify possible sources of microbial contamination and to assess the effect of good cleaning and sanitation practices on the microbial quality and safety of unpasteurized apple cider. Raw unwashed apples, washed apples, cleaning water, fresh cider, and finished cider samples were collected from five Ontario producers over 4 months and microbiologically tested. Total coliforms were found in 31, 71 and 38% of the unwashed apple, water, and washed apple samples, respectively. Escherichia coli was found in 40% of the water samples from one producer alone. The washing step was identified as a potential source of contamination, possibly due to water in the dump tanks seldom being refreshed, and because scrubbers, spray nozzles, and conveyors were not properly cleaned and sanitized. Higher total coliform counts (P < 0.0001) and prevalence (P < 0.0001) in fresh cider compared with those in unwashed apples and washed apples indicated considerable microbial buildup along the process, possibly explained by the lack of appropriate equipment sanitation procedures. Results showed that producers who had better sanitary practices in place had lower (P < 0.001) total coliform prevalence than the rest of the producers. Overall results show that good sanitation procedures are associated with improved microbial quality of fresh cider in terms of total coliforms and that operators who pasteurize and/or UV treat their product should still be required to have a sound good manufacturing practices program in place to prevent recontamination. Cryptosporidium parvum, an important pathogen for this industry, was found in different sample types, including washed apples, water, and fresh and finished cider.