不同原料苹果酒的酿造特性研究

以‘金世纪’单一苹果品种及‘金世纪’、‘嘎啦’、‘澳洲青苹’混合（1∶1∶1）苹果品种为原料酿造苹果酒,并对其进行理化指标、多酚物质、香气成分测定及感官品评。结果表明,两种苹果酒理化指标差异不显著（P＞0.05）;混合发酵苹果酒中的酚类物质总量（61.88 mg/L）显著高于单独发酵苹果酒（56.90 mg/L）（P＜0.05）,其中以原儿茶酸、儿茶素、原花青素、表儿茶素和绿原酸为主。香气主要以醇类和酯类物质为主,两种苹果酒中醇类物质含量分别为216.83 mg/L和78.85 mg/L;酯类以乙酸乙酯、乙酸丙酯、乳酸乙酯和乙酸己酯为主,前三者在混合发酵苹果酒中含量均显著高于单独发酵苹果酒（P＜0.05）,使其香气更加浓郁和复杂。混合发酵苹果酒在澄清度、回味、香气、风味平衡方面更好,但在色泽方面稍差。因此,混合苹果品种发酵更适合于苹果酒的酿造。     

苹果酒原料及酵母对酿造的影响

以红富士苹果和浓缩果汁为原料酿造苹果酒。加入亚硫酸(120mg／L)于苹果汁中，24h后90％以上的游离SO2变为结合态，此后波动不大。研究显示，1．5‰的皂土澄清效果最好；鲜汁的产酒率明显高于浓缩汁，酒液中可溶性固形物和还原糖少。果酒酵母1#的产酒率最高，残糖最少，挥发酸最少，而且滴定酸、pH的变化幅度较少。与浓缩果汁相比，鲜果汁酿造的酒中含有的香气成分如活性戊醇 异戊醇、正戊醇、正己醇、苯乙酸乙酯较多。     

Effect of sulphur dioxide concentration added at different processing stages on volatile composition of ciders

This study evaluated the effect of sulphur dioxide (SO₂) added at different steps in the process on the volatile composition contributing to the fruity aroma of cider. Potassium metabisulphite was added (150 and 300 mg/L) at three processing steps (a) crushed apple, (b) apple must and (c) final product. The SO₂ added to the crushed apple either maintained or increased the fermentation rate, whereas the addition to the apple must slowed the fermentation rate. The addition of 300 mg/L of potassium metabisulphite to Golden Delicious apple must inhibited fermentation. The losses of volatile compounds varied from 23 to 46% and from 33 to 97% in all of the treatments with 150 and 300 mg/L of potassium metabisulphite, respectively. 3‐Methyl‐1‐butanol, acetaldehyde and ethyl ethanoate corresponded to >85% of the volatile compounds in the cider; 3‐methyl‐1‐butanol was not affected by the sulphur dioxide. Acetaldehyde showed the greatest reduction (>80%) with the addition of sulphur dioxide and ethyl ethanoate was reduced when the compound was added to the crushed apple and apple must. All of the interactions between the apple variety, the stage of SO₂ addition and the concentration of SO₂ showed significant negative impact on volatile compounds. © 2018 The Institute of Brewing & Distilling     

滴定酸对苹果酒酿造的影响

用柠檬酸分别将浓缩苹果汁稀释至约 12°Bx滴定酸调节至 1 94～ 3 15 g/L(以苹果酸计 ) 5个水平 ,添加苹果酒酵母于 18～ 2 0℃发酵。随着发酵的进行 ,各发酵液的酸度升高。发酵降糖快 ,增酸速度快 ,并于发酵 3～ 4d升至峰值。过后 ,滴定酸降低 ,最终趋于稳定。成品酒滴定酸均高于对应果汁酸度。果汁滴定酸度越高 ,起发越快 ,升酸幅度越小 ,发酵后期降酸幅度也小。连二酮于发酵前期升至峰值后 ,迅速被还原至阈值以下。感官分析表明 :高发酵度苹果酒的滴定酸以 3 0 g/L左右为宜     

Influence of cider‐making process parameters on the odourant volatile composition of hard ciders

This study was performed to explore the relationships between some parameters of the French cider‐making process and the odourant compounds of cider. Sixteen ciders were prepared on a pilot plant scale using experimental design and varying according to apple blends, pressing conditions, pre‐fermentation clarification implementation and conditions, and biomass reduction during fermentation. Odourant compounds were extracted from final ciders by headspace solid‐phase microextraction with a CAR/PDMS fibre, a method previously shown to provide extracts representative of the studied cider. Extracts were analysed by gas chromatography coupled with mass spectrometry and flame ionization detection. All of the parameters tested had at least a slight effect on the odourant composition and particularly on the esters, which bring fruity notes that are appreciated by consumers. Clarification and biomass reduction had a greater impact than apple blend and pressing conditions. This could be explained by the influence of the nitrogen content on fermentation rate and efficiency, which affects the production of secondary metabolites. Under the conditions tested, a juice obtained from a bitter blend of apples by a slow pressing of the pulp at low temperature, after 1 h of cuvage, clarified by keeving and fermented without biomass reduction, produced a cider with the highest quantity of esters. These results could help cider‐makers enhance product quality according to consumer expectations. Copyright © 2015 The Institute of Brewing & Distilling     

贮藏和包装条件对苹果浓缩汁二次混浊形成的影响

本文研究了贮藏和包装条件对二次混浊物形成的影响.通过测定果汁的浊度以及与二次混浊有关的酚类和蛋白质的变化,阐明贮藏和包装条件对二次混浊形成的影响.二次混浊果汁的浊度及缩合单宁的含量随贮藏时间的延长和贮藏温度的升高而增加,小分子的酚类以及可溶性蛋白质的含量随贮藏时间的延长和贮藏温度升高而减少.贮藏期间二次混浊形成的浊度变化遵循一级反应方程.二次混浊现象随包装顶隙的增加而加重,用BOPP膜包装的果汁二次混浊比玻璃瓶和铝箔包装的严重,光照对果汁二次混浊的形成无影响.短时间或低温贮藏条件以及选择透氧率低的包装材料会减少二次混浊的形成.     

Effect of home processing on the distribution and reduction of pesticide residues in apples

The effect of home processing (washing, peeling, coring and juicing) on residue levels of chlorpyrifos, β-cypermethrin, tebuconazole, acetamiprid and carbendazim in apple segments was investigated. The pesticide residues were determined by UPLC-MS/MS and GC with a flame photometric (FPD) and electron capture detection (ECD). The results indicated that the pesticide residue levels in the apple peel and core were higher compared with in the apple flesh. After peeled and cored apple was processed into apple juice and pomace, chlorpyrifos, β-cypermethrin and tebuconazole were concentrated in the apple pomace. However, residues of acetamiprid and carbendazim were exceptions. The apple pomace was free of acetamiprid, which was mainly present in the apple juice. After washing the mean loss of chlorpyrifos, β-cypermethrin, tebuconazole, acetamiprid and carbendazim from apples under recommended dosage and twofold higher dosage were 17–21%, 6.7–7.1%, 13–32%, 42–67% and 47–50%, respectively. The pesticide residues were significantly reduced in the edible part of the apple except for β-cypermethrin during peeling and coring process. The removal effect of apple juicing was found to be the most pronounced on β-cypermethrin residue, which was reduced in the range of 81–84%, and the reductions of chlorpyrifos, tebuconazole, acetamiprid and carbendazim upon apple juicing were in the range of 15–36%.     

不同榨汁苹果的香气研究

研究了3个中熟期的苹果品种（津轻、红星、乔纳金）的完整果实及其鲜榨果汁的香气成分,利用固相微萃取-气质检测分析,总共鉴定出60种香气组分,其中对完整果实的香气收集方法采用静态顶空固相微萃取技术,结果表明此方法简单易行且结果较好。同时对果实的常规物理指标（硬度、pH、可溶性固形物和色泽）进行了分析,综合评价了苹果的质量与榨汁特性。     

CaCl_2对苹果酒酿造的影响

对以红富士苹果为原料 ,分别添加 0 3、0 4、0 5g/LCaCl2 的澄清苹果汁进行了研究。清汁中接种酿酒酵母Aw(Saccharomycescerevisiae ,Aw) ,于 2 0℃控温发酵 ,陈酿、澄清后进行理化、感官分析与风味物质测定。研究显示 ,添加CaCl2 显著地提高了果汁的澄清度、加快了果汁澄清速度。果汁处理时间低于 12h时 ,CaCl2 加量以 0 4g/L为宜 ;处理时间在 18～ 2 2h ,CaCl2 加量为 0 3～ 0 5g/L。经CaCl2 增加酸度 ( 1 49～ 1 5 7g/L)、降低 pH值 ( 0 19～ 0 2 4)、对酵母酒精发酵、发酵过程中滴定酸和 pH的变化趋势无显著影响。CaCl2 处理的果汁发酵的苹果酒滴定酸度高、残糖低 ,总浸出物低 ,酒精浓度与未处理苹果酒接近 ;口味纯正、爽口 ,色泽好 ,果香味突出。     

Inactivation of Escherichia coli K-12 in Apple Juice Using Combination of High-Pressure Homogenization and Chitosan

ABSTRACT:  Apple juice and apple cider were inoculated with Escherichia coli K-12 and processed using a high-pressure homogenizer to study bacterial inactivation. Seven levels of pressure ranging from 50 to 350 MPa were used in the high-pressure homogenizer. Two types of chitosan (regular and water soluble) with 2 levels of concentration 0.01% and 0.1% were investigated for synergistic effect with high-pressure homogenization for the bacterial inactivation. E. coli K-12 inactivation was evaluated as a function of homogenizing pressure at different concentration of 2 types of chitosan in apple juice and cider. High-pressure homogenization (HPH) induced significant inactivation in the range of 100 to 200 MPa, while thermal inactivation was the primary factor for the bacterial inactivation above 250 MPa. Significant ( P < 0.05) 2-way interactions involving pressure and type of substrate or pressure and chitosan concentration were observed during the study. The homogenization pressure and the incremental quantity of chitosan (both types) acted synergistically with the pressure to give higher inactivation. Significantly ( P < 0.05) higher inactivation was observed in apple juice than apple cider at same homogenizing pressure. No effect of type of chitosan was observed on the bacterial inactivation.     

Influence of Enzymatic Clarification with a Pectin Methylesterase on Cider Fermentation

In this study, the effect of two apple juice treatments (clarification with a pectin methylesterase in the presence and absence of sulphiting) on the cidermaking process was investigated. Pre‐fermentative clarification with the pectin methylesterase (Rapidase CPE) slowed the alcoholic fermentation in respect to traditional fermentation, the greatest effect being found for the combination of the enzymatic treatment with sulphur dioxide addition. With this treatment the start of the fermentation was delayed seven days. Enzymatic clarification delayed malolactic fermentation (MLF) and the interaction of both treatments produced a cider in which malolactic fermentation had not occurred. Both treatments ensured that the volatile acid levels during the maturation phase were significantly lower than in the traditional fermentation. Enzymatic clarification led to lower levels of yeasts during the active phase of alcoholic fermentation with respect to the control. When this treatment was combined with sulphiting, a decrease in apiculate yeast numbers during alcoholic fermentation was observed and a better survival of these species was noted after 59 days of fermentation.     

胡萝卜苹果复合饮料加工工艺研究

对胡萝卜苹果复合饮料加工工艺进行了研究,通过正交实验得到最佳配方及均质参数为：胡萝卜汁40%、苹果汁20%、蔗糖5%、柠檬酸0.2%、耐酸CMC0.15%、黄原胶0.05%,高压均质压力20MPa,温度70℃,均质2次。     

(+)‐Catechin and (−)‐epicatechin levels of concentrated and ready‐to‐drink grape juices through storage

Commercial concentrated Concord (CCJ) and Isabel (CIJ) grapes juices were stored at 4–5 °C while pasteurised ready‐to‐drink juices of the same grape cultivars (PCJ and PIJ) were kept at 20–25 °C under indirect light for 10 months, simulating industrial storage conditions. (+)‐catechin preservation during storage ranged between 63% (PCJ) and 52% (PIJ); (?)‐epicatechin retention was of 32% (CCJ) and 15% (CIJ). Total phenols retention ranged from 93% (CCJ) to 84% (PCJ) and radical scavenging activity (RSA) from 87% (PIJ) to 85% (CCJ and PCJ). Concentrated juices showed higher monomeric flavan‐3‐ols amounts and CCJ depicted superior phenolic contents. PIJ yielded the highest RSA during storage per phenolic unit. Process and storage impacted flavan‐3‐ols and not total phenolics and RSA during 10‐month ageing.     

Effect of Dipping and Vacuum Impregnation Pretreatments on the Quality of Frozen Apples: A Comparative Study on Organic and Conventional Fruits

The effect of dipping and vacuum impregnation (VI) pretreatments with lemon juice solution on the quality and stability of organic and conventional frozen apples was investigated. Fresh apples were characterized; organic apples showed, at equal starch and ripeness index, a lower sugar content, and higher acidity than conventional ones. The polyphenol content was slightly higher in organic apples than in conventional ones while polyphenoloxidase activity was similar. No differences in color and firmness were evidenced. Dipping affected organic and conventional apples’ color by determining an increase of lightness (ΔL^* ≈ 4) and h° (Δh° ≈ 6) parameters. VI reduced the lightness of apples (ΔL^* ≈ ?3) but the addition of lemon juice counterbalanced the lightness reduction by increasing ΔL^* from 3 to 1.5 ca. Pretreatments did not affect the firmness of organic fruits while impaired that of the conventional ones ( 26% on average), likely due to different fruit matrix porosity and cell wall composition. Freezing (?40 °C) and frozen storage (up to 300 days) dramatically reduced the firmness of organic (42%) and conventional products (58%). At equal pretreatment and storage time (that is, 15, 30, 300 days), higher firmness retention was evidenced in organic apples than in conventional ones. All through frozen storage, VI was shown to better preserve the mechanical properties of organic apples than that of conventional ones. Both freezing and frozen storage reduced the hue of frozen apple products by up to 8% due to browning reactions. Lemon juice addition increased the hue of both frozen samples and thawed samples by about 2% all through storage time.     

Comparative study of polyphenolic content and antiradical activity of cloudy and clear apple juices

Clear and cloudy apple juices from Idared and Champion varieties were studied for their radical‐scavenging effects. The polyphenolic content and composition of the juices before and after thiolysis were determined by high‐performance liquid chromatography with diode array detection. Cloudy juices, especially that prepared from Champion variety, had a higher content of procyanidins than clear juices. Radical‐scavenging activity was measured by electron paramagnetic resonance (EPR) spectroscopy using the stable 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical. All juices showed long‐lasting radical‐scavenging activity, and EPR spectra were recorded over time to follow the reaction kinetics. Scavenging of DPPH showed pseudo‐first‐order kinetics, which might be expected in the presence of polymerised antioxidants that prevent closer contact between the DPPH radical and hydroxyl groups. The content of polymeric procyanidins showed a linear dependence on the rate constant, suggesting that these compounds are mainly responsible for time‐extended radical‐scavenging activity. The antioxidant properties of apple juices were much better reproduced by EPR spectroscopy than by UV–visible measurements. The former method is especially sensitive to the concentration of polymerised or bound procyanidins, whilst the latter method requires transparent (clear) samples. Apple juices, especially cloudy ones, are a rich source of natural antioxidants that may be used in the pharmaceutical or food industry. Copyright © 2006 Society of Chemical Industry     

Effect of enzyme‐aided pressing on anthocyanin yield and profiles in bilberry and blackcurrant juices

Bilberries (Vaccinium myrtillus) and blackcurrants (Ribes nigrum) were treated with extensive dosages of commercial cell wall degrading enzyme preparations, i.e. Econase CE, Pectinex Ultra SP‐L, Pectinex Smash, Pectinex BE 3‐L and Biopectinase CCM. The enzymes were dosed based on the polygalacturonase activity. The juice yield was improved in both berries as a result of the enzymatic treatment. The improvement was more pronounced with blackcurrants owing to their thicker cell walls. The impact of the enzymatic treatment on anthocyanins present in the juices was investigated using HPLC‐DAD. The enzyme preparations affected the contents and composition of anthocyanins in the juices. Pectinex Ultra SP‐L, Pectinex Smash, Pectinex BE 3‐L and Biopectinase CCM increased the total content of anthocyanins by 13–41% in the bilberry juices and by 18–29% in the blackcurrant juices. Econase CE, however, produced a dramatic decrease in the total anthocyanin content in the bilberry juice due to its enzyme profile, whereas no such effect was observed with the blackcurrant juice. All the enzyme mixtures tested produced a total or extensive loss of anthocyanidin galactosides in bilberry juice. Commercial enzyme preparations used in the production of berry juices can improve extraction of anthocyanins into the juice. However, they may effectively hydrolyse certain glycosides and thus affect the profile of extracted anthocyanins. Copyright © 2005 Society of Chemical Industry     

Processing and analytical characterisation of pulp-enriched cloudy apple juices

Pulp-enriched cloudy apple juices were manufactured from two apple varieties by blending of apple puree with natural cloudy apple juice in order to enrich bioactive secondary plant substances. Finishing of the puree with a 0.6-mm mesh screen and final product homogenisation revealed as the optimum processing technology for the novel 100% fruit beverage. The presence of large particles originating from the puree prevented long-term cloud stability, but due to the proportion of cloud-stable juice a complete phase separation did not occur. Optimal drinkability was achieved at a viscosity of 11.5 mPa s. Polyphenol compositions and concentrations were determined by means of RP-HPLC/PDA. The results ranged from 109 to 610 mg/l. All samples showed the typical polyphenol pattern of apples with dominating hydroxycinnamic acids followed by flavanols and flavonols. The puree addition to the cloudy apple juices increased the polyphenol concentrations by average 100%. Relatively, the highest increase could be observed for dimeric procyanidins. Different technological variants did not affect significantly the polyphenol concentrations. The dietary fibre contents of the pulp-enriched cloudy apple juices ranged from 5.8 to 9.4 g/l.