品种和后成熟度对非浓缩还原苹果汁浑浊稳定性的影响

该研究从原料加工适宜性出发,探究不同品种(华硕、富士、嘎啦、金冠、澳洲青苹)和后熟度对非浓缩还原(not from concentrate, NFC)苹果汁浑浊稳定性的影响。结果表明,品种和后成熟对NFC苹果汁的浑浊稳定性影响显著。对比不同品种,发现华硕苹果汁最不稳定,浊度最低(4.21～5.95),分层沉淀严重,而其他品种苹果汁在后熟过程中浑浊稳定性呈现上升趋势,如金冠苹果汁浊度值从3.39上升到66.40,这可能与果汁沉淀敏感物质随后熟的变化有关。在后熟过程中,NFC苹果汁的不溶性淀粉和聚合敏感多酚类物质含量显著降低(P<0.05),例如澳洲青苹汁的不溶性淀粉含量由5.20 mg/L下降至无法检出,华硕苹果汁总酚含量由291.63 mg没食子酸/100mL降低至2.55 mg没食子酸/100mL。而随着后熟,NFC苹果汁的果胶含量显著升高(P<0.05),例如金冠苹果汁的果胶含量由0.66 mg/mL上升到7.34 mg/mL。这些沉淀敏感物质组分的变化,使得NFC苹果汁的浑浊稳定性显著提高。该研究结果将为改善NFC苹果汁浑浊稳定性提供理论依据。     

秦冠、富士、澳洲青苹生长发育期间品质特性分析

对秦冠、富士、澳洲青苹3 个品种生长期间的品质特性进行分析。参照国标测定可溶性固形物、VC 含量;参照行标测定总酸;采用QTS-25 质构仪测定硬度;采用固相微萃取结合气质联用测定成熟后香气成分。结果显示：3 个品种在生长期间各指标差异显著。3 个品种在生长期间,总酸、VC 含量、硬度指标均呈现下降趋势,可溶性固形物和固酸比均呈上升趋势。秦冠和富士可溶性固形物和固酸比均高于澳洲青苹,秦冠硬度变化较小,澳洲青苹总酸和VC 含量显著高于秦冠和富士。3 个品种成熟后香气分析共检测出43 种物质,各品种香气差异显著：秦冠、富士主要香气为酯类和醇类,属果香型;澳洲青苹主要香气为醛类和醇类,属青香型。富士和秦冠中己酸乙酯、乙酸己酯、2- 甲基-1- 丁酯差异较小,而乙酸-2- 甲基-1- 丁酯与澳洲青苹相比差异显著,澳洲青苹香气中(E)-2- 己烯醛含量37.042%,显著高出秦冠。     

不同品种苹果采后品质和挥发性物质的差异分析

为明确不同品种苹果采后品质和挥发性物质的差异,本文通过电子鼻结合顶空固相微萃取及气相-质谱联用技术(HS-SPME-GC-MS)分别测定不同品种(‘金冠’、‘嘎啦’、‘乔纳金’、‘寒富’)挥发性物质成分和含量,并对品质指标进行探讨。结果表明,‘金冠’呈现明亮绿黄色,果形指数最高,‘嘎啦’为有光泽红色,但可食率不高,‘乔纳金’为红黄色,果形指数最低,‘寒富’为红橙色,果实质量最大;‘寒富’可溶性固形物含量最大,而‘金冠’可滴定酸含量和维生素C含量最高,‘金冠’苹果和‘嘎啦’苹果硬度和脆性较高。电子鼻主成分分析和线性判别分析表明,可将4个品种苹果完全区分。GC-MS结果表明,共检测到7类33种化合物,主要挥发性物质为醇类、醛类、酯类。4个品种都具有的特征性香气成分是己醛(青草味)、2-己烯醛(绿苹果味)、乙酸己酯(果香味),1-己醇(青草味)是‘嘎啦’、‘金冠’苹果的特征挥发性成分,乙酸丁酯(果香)是‘嘎啦’苹果的独有特征挥发性成分,总体上‘嘎啦’苹果香气浓郁,‘寒富’苹果香气较淡,这与电子鼻分析结果相吻合。     

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。     

采用主成分分析法对六个苹果品种果实香气分析及分类

全面分析六个苹果品种果实香气成分特点和主要差异。采用顶空固相微萃取结合气质联用检测香气成分。确定了六个苹果品种特征香气成分,采用主成分分析法确定出乙酸己酯、2-甲基丁酸己酯、乙酸丁酯、乙酸异戊酯、己酸己酯和己醛是苹果香型分类的重要判定变量,将六个苹果品种香气分为三类。各品种均以醛类青香气为主,第一类"醛类浓青香型",酸王香气浓度很高,是其它品种约2～4倍,属于此类;第二类"醛类淡青香型",香气成分比较单纯且含量低,澳洲青苹、国光、瑞丹和瑞林属于此类;第三类"青香蕉香型",酯类香蕉香气化合物含量较高,青香蕉属于此类。     

产地对富士苹果香气成分的影响

研究了河北省苹果栽培区中保定、承德、衡水、秦皇岛、石家庄、邢台6个地区富士苹果的香气成分,为了解富士苹果的香气成分受产地的影响提供理论依据。采用顶空固相微萃取和气相-质谱联用技术,测定了45个果样的香气成分及其含量,并对其中酯类、醛类、醇类含量的差异性进行了探讨。富士苹果的香气成分有酯类、醛类、醇类等4类35种化合物,其主要的香气成分为乙酸丁酯、乙酸己酯、乙酸-2甲基丁酯、己醛、2-己烯醛、1-丁醇、2-甲基丁醇、1-己醇。酯类和醛类含量较高的地区为在河北省海拔较高的承德、石家庄、邢台,醇类含量较高的地区为海拔较低的秦皇岛、保定。     

低温低氧工艺对苹果汁品质与香气特征的影响

以红富士苹果为原料,通过3 种不同工艺制作苹果汁并对其基本理化指标、抗氧化活性及香气特征进行分析,试验结果表明：与浓缩还原苹果浊汁相比,非浓缩还原（not from concentrate,NFC）苹果汁可以更好地保留苹果中的各种有效成分及香气特征,与传统工艺NFC 苹果汁相比,低温低氧工艺NFC 苹果汁由于在加工过程中加热程序少,工艺流程短,可以最大程度地保留苹果中的有效活性成分,总酚含量可达626.74 mg/L,显著高于传统工艺NFC（P＜0.05）,同时可以更好地保留新鲜苹果的香气特征,挥发性成分总含量为133.02 mg/L,产生的不良风味也相对较少。     

胡柚汁益生菌发酵挥发性风味特征

利用筛选到的2株乳酸菌植物乳杆菌L1（Lactobacillus plantarum）和发酵乳杆菌L2（L. fermentum）对胡柚汁发酵,研究其挥发性风味成分及其变化特征。采用静态-顶空固相微萃取和气相色谱-质谱联用分析方法,测定胡柚汁经此2种乳酸菌发酵后挥发性风味物质组分和相对含量,运用主成分分析法对发酵胡柚汁样品挥发性风味成分进行分析,并采用电子鼻对乳酸菌发酵胡柚汁的香气进行检测。结果表明,胡柚汁经发酵后共鉴定出79种挥发性风味物质,其中醇类20种、烯烃类15种、烷烃类12种、酮类10种、醛类5种、酯类2种、其他类15种,挥发性风味物质分别为59、36种和35种。经乳酸菌发酵后,胡柚汁挥发性风味化合物种类均增加,并检测到了胡柚汁中未被检测到的酯类、醇类、酮类和烷烃类相对含量显著提高,醛类物质相对含量大量降低。主成分分析找出了影响4个样品特征风味组分在主成分中的差异,表明主成分分析法可实现对乳酸菌发酵胡柚汁特征风味差异性的评价。电子鼻分析表明胡柚汁经不同乳酸菌发酵后风味差异显著。研究结果揭示了胡柚汁乳酸菌饮料的风味特征并为产品质量评定等提供依据。     

基于GC-MS法的椰子水及其饮料的风味成分分析

为了对不同成熟度椰子(椰青、嫩椰子、成熟椰子)的椰汁及椰子水饮料中挥发性风味物质组分和含量进行分析,采用蒸馏萃取装置提取样品中的挥发性成分,并用气相色谱-质谱(GC-MS)联用分析技术进行分离鉴定。结果表明,共检测出67种香气成分,分为7大类化合物,包括酯类32种,有机酸11种,醇类7种,醛类3种,酮类3种,酚类4种,其他类7种。在检出的香气物质中,确定主体风味组分主要是醇类、酯类和酸类3类物质,相同的挥发性成分是2,3-丁二醇。不同样品中,这些微量香气成分的种类含量有较大差别,成熟椰子原汁中风味物质的种类和含量较多。因此,椰子水原汁的挥发性成分直接影响椰子水饮料的感官质量。本试验研究为椰子水及其饮料感官品质的深入研究提供了一定的理论依据。     

不同品种和成熟度苹果汁品质及贮藏稳定性研究

以秦冠、华冠、新红星、乔纳金、富士、澳洲青苹六种苹果作为研究对象,分别在生理成熟和完全成熟时进行采摘。对其苹果汁的p H、酸度、总酚、黄烷醇、原花青素、可溶性固形物含量、苹果汁酶促褐变和非酶促褐变进行测定,结果得到:秦冠苹果汁酶促褐变率最低,华冠、乔纳金非酶促褐变率最低,澳洲青苹最高。相比生理成熟的苹果,完全成熟的苹果更适合用于制作果汁。     

COMPARISON OF VOLATILE COMPOUNDS IN TWO SEASONS IN APPLES: GOLDEN DELICIOUS AND GRANNY SMITH

Fruit of varieties Golden Delicious and Granny Smith, were harvested at commercial maturity in two consecutive years (1993 and 1994). The aroma components obtained were analyzed by the dynamic headspace method and quantified by gas chromatograph-mass spectrometry. In Golden Delicious the total esters represented more than 80% of the total volatile components in both years, consistent with Drawert's classification (1975). However, Granny Smith did not, since the esters made up 72 and 88% of total volatiles in the years 1993 and 1994, respectively. The aroma components are different in class and quantity and give a characteristic sensorial perception for each type of fruit and variety. In Golden Delicious, ethyl propionate and butyl acetate gave a fruity aroma in 1993 and ethyl acetate, ethyl propionate and propyl acetate were the predominant compounds in 1994. In Granny Smith the aroma composition was slightly different in the two years. In 1993 the aromatic profile did not show the predominance of any compound, while in 1994 it was more fruity due to the higher content of ethyl propionate and propyl acetate.     

Kinetic and Multivariate Analysis of Polyphenol Oxidase Inactivation by High Pressure and Temperature Processing in Apple Juices made from Six Different Varieties

The effectiveness of high pressure processing on the inactivation of apple polyphenol oxidase has been widely investigated. However, from an industrial point of view, there is a need for assessing this effectiveness on each one of the different apple varieties that each company uses for their products. This piece of work fills in this gap, studying the effect of the variety on apple juice polyphenol oxidase inactivation. Six varieties were assayed (Braeburn, Fuji, Gala, Golden Delicious, Granny Smith, and Red Delicious), searching for this influence from two different approaches: a kinetic study, finding the best model for each one of them, and a multivariate part consisting of a principal component analysis of data.     

Changes on colour parameters caused by high‐pressure processing of apple juice made from six different varieties

The colour changes caused by high‐pressure processing at different temperatures of apple juice were investigated. Six apple varieties were used (Braeburn, Fuji, Gala, Golden Delicious, Granny Smith and Red Delicious), searching for the influence of the variety from two different approaches: a kinetic study, finding the best model for each one of them, and a multivariate study consisting of a principal component analysis of data. Although it had lower initial values, redness (a*) was more influenced by high pressure than yellowness (b*). The pattern followed by colour changes was found to be definitively dependent on the variety. High‐pressure processing affects in a stronger way the absorbances located near 400 nm (i.e. 400.5 nm in Fuji and 434.0 nm in Braeburn).     

In Vitro and In Vivo Flavor Release from Intact and Fresh‐Cut Apple in Relation with Genetic,Textural, and Physicochemical Parameters

Abstract: Flavor release from 6 commercial apple cultivars (Fuji, Granny Smith, Golden Delicious, Jonagold, Morgen Dallago, and Red Delicious) under static conditions (intact or fresh‐cut samples) and during consumption of fresh‐cut samples (nosespace) was determined by proton transfer reaction mass spectrometry. Textural (firmness, fracturability, flesh elasticity, and rupture) and physicochemical (pH, acidity, and water content) properties of the apples were also measured. Static headspace analysis of intact fruits revealed Fuji and Granny Smith apples had the lowest concentration for all measured flavor compounds (esters, aldehydes, alcohols, and terpenes), whereas Red Delicious apples had the highest. Fresh‐cut samples generally showed a significant increase in total volatile compounds with acetaldehyde being most abundant. However, compared to intact fruits, cut Golden and Red Delicious apples had a lower intensity for ester related peaks. Five parameters were extracted from the nosespace data of peaks related to esters (m/z 43, 61), acetaldehyde (m/z 45), and ethanol (m/z 47): 2 associated with mastication (duration of mastication–t_con; time required for first swallowing event–t_swal), and 3 related with in‐nose volatile compound concentration (area under the curve–AUC; maximum intensity–I_max; time for achieving I_max–t_max). Three different behaviors were identified in the nosespace data: a) firm samples with low AUC and t_swal values (Granny Smith, Fuji), b) mealy samples with high AUC, I_max, t_swal values, and low t_con (Morgen Dallago, Golden Delicious), and c) firm samples with high AUC and I_max values (Red Delicious). Strengths and limitations of the methodology are discussed. Practical Application: Volatile compounds play a fundamental role in the perceived quality of food. Using apple cultivars, this research showed that in vivo proton transfer reaction mass spectrometry (PTR‐MS) could be used to determine the relationship between the release of volatile flavor compounds and the physicochemical parameters of a real food matrix. This finding suggests that in vivo PTR‐MS coupled with traditional physicochemical measurements could be used to yield information on flavor release from a wide range of food matrices and help in the development of strategies to enhance food flavor and quality.     

Non-destructive evaluation of ripening and quality traits in apples using a multiparametric fluorescence sensor

BACKGROUND: The detection of pigments and colourless flavonoids in apples can provide a useful indication of fruit quality. Optical methods are preferable because they are fast and non‐destructive. In this study, a fluorescence‐based portable sensor was used in order to non‐invasively determine the content of chlorophylls, anthocyanins and flavonols in Fuji, Granny Smith and Golden Delicious apple cultivars. The aim was to define new non‐destructive optical indices of apple quality. RESULTS: The anthocyanin index (ANTH) in Fuji was higher in the sunny (i.e. sun‐exposed) side of the fruit compared to the shady side. For all cultivars, the flavonol index (FLAV) was higher in the sunny side compared with the shady side. The chlorophyll index (CHL) for the shady sides of Granny Smith and Golden Delicious was significantly higher than for the sunny sides. Fine linear regressions were found between the ANTH, FLAV and CHL indices and the actual anthocyanin, flavonol and chlorophyll concentrations, respectively, which were determined destructively on the apple peel extracts. A negative correlation was found between the apple sugar content and the chlorophyll fluorescence in the far‐red spectral band. CONCLUSION: Our results indicate that a single multiparametric fluorescence‐based sensor can provide valuable non‐destructive markers of ripening and quality in apples. Copyright © 2012 Society of Chemical Industry     

1-MCP处理对不同成熟度富士苹果贮后货架品质和挥发性物质的影响

为了明确1-甲基环丙烯(1-MCP)对不同成熟度的苹果品质和挥发性物质的影响规律,以不同成熟度的富士苹果为试材,采后进行1 μL/L的1-MCP处理,然后在(-0.5±0.3)℃贮藏10个月后出库,测定理化指标,并分析不同成熟度1-MCP处理苹果在货架期间果实挥发性物质种类和含量的变化。结果表明,1-MCP处理能够延缓不同成熟度苹果中可溶性固形物、可滴定酸含量和质地的下降,其中1-MCP处理对低成熟度果实保鲜效果更明显。HS-SPME/GC-MS分析表明,己醛(青草及苹果香味)和2-己烯醛(新鲜水果型清香)是富士苹果的主要挥发性物质。在货架初期,高成熟度的果实检测出酯类物质的种类和含量高于低成熟度果实;1-MCP处理的果实中酯类挥发性物质含量降低,使果实的香气变淡,而醇类、醛类物质含量升高;随着果实的成熟,生理代谢旺盛,1-MCP处理成熟低的果实挥发物质含量升高。     

Preliminary study of the production of apple pomace and quince jelly

Apple pomace, a cheap by-product of apple juice and cider production, is rich in pectins and flavour compounds. Thus, a possible way of valorization of apple pomace was using it for jelly production. Fresh apple pomace from Braeburn, Gala, Golden Delicious and Granny Smith was used for the preparation of jelly to study the amount of sugar and quince content and the cooking time effect. The response surface methodology was used to study the preparation of apple pomace jelly and responses studied were textural characteristics and overall acceptability. The hardness of jelly was not affected by the factors studied whereas cohesiveness and overall acceptability were affected by the concentration of quince and sugar. The most appreciated jellies were those prepared with the highest quince concentration and the lowest sugar concentration.     

Potential Prophylactic Properties of Apple and Characterization of Potent Bioactive from cv. “Granny Smith” Displaying Strong Antimutagenicity in Models Including Human Lymphoblast TK6+/− Cell Line

Potential prophylactic attributes in terms of antimutagenicity, antioxidant, and radioprotective properties were evaluated for 8 common apple cultivars namely “Fuji,” “Golden Delicious,” “Granny Smith,” “Ambri Kashmiri,” “Kinnaur,” “Red Delicious,” “Royal Gala,” and “Shimla,” where cultivar based significant variation was observed. Cv. “Granny Smith” displayed significantly higher and broad spectrum antimutagenicity in Escherichia coli rpoB based rifampicin resistance (Rif^R) assay, whereas, “Ambri Kashmiri,” “Royal Gala,” and “Shimla” showed lower antimutagenicity. Cultivars “Ambri Kashmiri,” “Kinnaur,” and “Red Delicious” exhibited strong antioxidant activity than cv. “Granny Smith” as assayed by radical scavenging, reducing potential and radioprotective property assays. The antioxidant and radioprotective properties were found to be better correlated than antimutagenicity. Suppression of error‐prone DNA repair pathway (such as E. coli SOS response) was found to be one of the possible mechanisms contributing to its antimutagenicity. Phenolic extract of “Granny Smithˮ showing higher antimutagenicity was HPLC purified and the bioactive fraction (t_R 35.4 min) contributing maximally (∼80%) to the observed antimutagenicity was identified as procyanidin dimer (PD) by ESI‐MS/MS. The above observed antimutagenicity in bacterial assay system was well reproduced in Thymidine Kinase Mutation (TKM) assay performed using human lymphoblast cell line (TK6^+/−) cell line making the findings more prophylactically relevant.     

EFFECTS OF THE RATE OF HEATING ON APPLE AND PEAR FRUIT QUALITY

There is evidence that the rate of heating to meet quarantine security impacts fruit quality as well as insect mortality. Linear heating rates, of 4, 6, 8, 10, and 12C/h to treatment temperatures of 44 and 46C were used to treat 8 cultivars of apples (‘Delicious’, ‘Golden Delicious’, ‘Granny Smith’, ‘Fuji’, ‘Gala’, ‘Jonagold’, ‘Braeburn’, and ‘Cameo’) and two cultivars of winter pear (‘d'Anjou’ and ‘Bosc’). Fruit were stored, ripened, and tested for various quality parameters. Scald was controlled, firmness was higher in heat treated fruit, ripening was delayed but uniform in pears, decay organisms were suppressed, red fruit became redder and green fruit remained green, the Brix‐acid ratio (SS/TA) was either unchanged (‘Granny Smith’) or increased. Physiological disorders such as bitter pit were exacerbated by the heat treatment, requiring culling after treatment to avoid storage of fruit so affected.