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。     

秦冠和红富士苹果对机械损伤的敏感性分析

为加深对苹果机械损伤的认识,更好地解决苹果采后机械损伤难题,通过人工模拟试验方法,比较60 cm高度跌落碰撞后秦冠和红富士苹果的损伤程度,以及机械损伤对两种苹果贮藏品质和生理反应的影响。试验结果表明:在同一碰撞条件下,红富士比秦冠苹果更容易产生机械伤,贮藏过程中,伤口面积和深度不断增加,红富士苹果伤口增幅大于秦冠;红富士和秦冠机械伤果在贮藏过程中呼吸强度均增大,红富士果实呼吸峰提前,秦冠的呼吸峰没有提前,而红富士果实的硬度、可滴定酸含量、失重率降幅均小于秦冠,两者可溶性固形物含量变化几乎没有差异。红富士比秦冠苹果对机械损伤更为敏感,而相同的机械损伤对秦冠苹果的生理反应和贮藏品质影响较红富士更大。     

一氧化氮缓释熏蒸处理对鲜切苹果片品质的影响

本文研究一氧化氮(nitric oxide,NO)气体缓释熏蒸处理对鲜切苹果片品质变化的影响。以红富士苹果为试材,将鲜切苹果片与NO供体二乙烯三胺一氧化氮聚合物(diethylenetriamine/nitric oxide,DETANO)、柠檬酸及玉米淀粉制成的NO气体缓释剂共置于密闭容器中,在4℃条件下贮藏。贮藏期间测定鲜切苹果片的表面明度(lightness,L*)值、果肉硬度、失重率、总酚含量、多酚氧化酶(polyphenoloxidase,PPO)活性、可溶性固形物含量、维生素C含量以及可滴定酸含量。结果表明:与对照组相比,NO气体缓释熏蒸处理能有效减轻鲜切苹果片的表面褐变、果肉软化和失重,显著抑制总酚含量的下降和PPO活性的升高,并保持可溶性固形物、维生素C和可滴定酸含量,延缓鲜切苹果片的品质劣变,为鲜切苹果片的贮藏保鲜提供了一种新方法。     

苹果多酚抗氧化活性的研究

本文研究了红富士苹果和国光苹果中多酚类物质的抗氧化活性。结果表明两种苹果果实总酚含量具有显著性差异。抗氧化实验结果表明两种苹果果实酚类提取液均具有很强的抗氧化活性，对^.OH、O2^.-、R^.有较明显的清除效果。     

不同水分活度对脱水苹果片抗氧化性的影响

以苹果为原料,研究不同水分活度对脱水苹果片抗氧化活性及贮藏稳定性的影响,结果表明:随着贮藏期的延长,水分活度高的脱水苹果片总酚、总黄酮、抗坏血酸和抗氧化能力下降幅度均高于水分活度低的样品。漂烫处理后脱水苹果片总酚、总黄酮含量和抗氧化能力高于非漂烫处理的脱水苹果片,抗坏血酸含量低于非漂烫处理的脱水苹果片。综合各项指标,水分活度0.605是脱水苹果片最佳贮藏水分活度。     

不同品种猕猴桃果实的品质及抗氧化活性

测定10 种猕猴桃VC、可溶性固形物、可滴定酸、总酚、蛋白质和氨基酸含量,并据此进行聚类分析,通过比较其清除DPPH自由基的能力,探究抗氧化活性与VC、总酚含量的相关性。结果表明：猕猴桃成熟果实含可溶性固形物含量12.27%～20.37%、可滴定酸含量0.85%～1.77%、VC含量54.86～159.08 mg/100 g、蛋白质含量0.86%～1.85%、总氨基酸含量10.74～17.94 mg/g、总酚含量63.71～152.46 mg/100 g、对DPPH自由基的清除率为13.75%～68.34%。6 种营养成分在不同猕猴桃品种之间具有一定差异性,其中翠香、红阳、金桃和华优的可溶性固形物、VC和总酚含量均较高,而黄金果和海沃德的VC、总酚含量较低,其他品种的营养成分指标基本处于中等水平,华优的VC含量（159.08 mg/100 g）、总酚含量（152.46 mg/100 g）及DPPH自由基清除率（68.34%）最高,是营养价值最高的品种之一。猕猴桃的抗氧化能力与其中的VC和总酚含量之间呈现较高相关性,表明猕猴桃的抗氧化作用与其中所含的VC和酚类物质关系密切。     

山西不同品种枣果品质特性及抗氧化活性研究

为探究山西不同品种枣果的品质特性及抗氧化能力的差异,选取山西省内8种代表性红枣品种(稷山板枣、壶瓶枣、临猗梨枣、吕梁木枣、交城骏枣、官滩枣、保德油枣、郎枣)探究其全红成熟期枣果的可溶性固形物、可滴定酸、维生素C、总酚、总黄酮、可溶性糖、有机酸、β-胡萝卜素、三萜酸含量及抗氧化能力。研究结果表明:稷山板枣可溶性固形物、总酚、β-胡萝卜素、果糖、蔗糖、山梨醇、白桦脂酸、齐墩果酸含量较其他品种高,抗氧化活性最强(DPPH自由基清除能力为9.3 mg TE/gDW,FRAP铁还原能力为781 mg AAE/100 gDW);郎枣的可滴定酸、维生素C、熊果酸含量最高;交城骏枣的葡萄糖含量最高;临猗梨枣的苹果酸、柠檬酸、琥珀酸含量最高;吕梁木枣的富马酸含量最高。     

不同溶剂提取对刺梨物质含量变化及抗氧化活性的影响

为探究不同极性的溶剂提取对刺梨物质含量变化及抗氧化活性的影响,分别以水、甲醇、60%乙醇、无水乙醇、正丁醇和乙酸乙酯为提取溶剂,通过测定提取物中抗坏血酸、总多酚、总黄酮、单宁和总三萜含量,采用体外抗氧化方法对刺梨不同溶剂提取物进行抗氧化活性测定,并采用抗氧化活性综合（antioxidant potency composite,APC）指数法进行比较分析。结果表明：60%乙醇提取物中总多酚、总黄酮、单宁和总三萜含量最高;水提取物中抗坏血酸含量最高;乙酸乙酯提取物中总多酚、总黄酮、抗坏血酸和总三萜含量最低;正丁醇提取物中单宁含量最低。对抗氧化活性而言,60%乙醇提取物清除DPPH 自由基与ABTS+自由基能力和还原力最强;甲醇提取物的羟基自由基清除率最高;乙酸乙酯提取物清除超氧阴离子自由基的能力最强。APC 指数显示,6 种溶剂提取物的抗氧化能力由强到弱依次为60%乙醇提取物＞甲醇提取物＞水提取物＞无水乙醇提取物＞乙酸乙酯提取物＞正丁醇提取物。由于不同活性成分之间存在协同或拮抗作用,且不同活性成分在不同溶剂中的溶解性不同,因此不同溶剂提取对刺梨活性物质含量和抗氧化活性影响较大。     

新疆野生苹果(Malus sieversii)的总多酚、总黄酮提取物的抗氧化活性研究

以采集于新疆不同地区的20个野生苹果品种为研究对象,福林酚法测总多酚,分光光度计法测定总黄酮,DPPH、ABTS、还原能力法测定总抗氧化能力,相关系数法分析各个指标之间的相关性。结果显示,不同品种的野生苹果的总多酚、总黄酮及抗氧化活性之间具有显著差异,其中,HDM-23的总多酚含量最高(4714.33μmol没食子酸/100g鲜果),XY-31的总黄酮含量最高(2452.84mg芦丁/100g鲜果)。总多酚、总黄酮及抗氧化活性之间呈极显著(p0.01)正相关,表明总多酚与总黄酮是野生苹果抗氧化活性的主要贡献物质。     

老黑谷米中多酚化合物的提取及体外抗氧化活性研究

以老黑谷米面粉为原料,提取分离其中的可溶性多酚、游离多酚、酯化多酚、醚化多酚、键合多酚,利用比色法进行多酚和类黄酮含量测定,并采用DPPH自由基清除能力、铁离子还原/抗氧化能力测定(FRAP)、总抗氧化能力测定(TEAC)、还原能力测定(RP)和H2O2清除活性等5种不同的体外抗氧化测定体系进行抗氧化活性测定。结果表明:5种多酚中,可溶性多酚含量最高,酯化多酚含量次之,显著高于游离多酚、醚化多酚、键合多酚。多酚中类黄酮含量最高为键和多酚和可溶性多酚,显著高于其他3种多酚。5种多酚均有较高的体外抗氧化能力,键合多酚的DPPH自由基清除能力最高,可溶性多酚的H2O2清除能力、FRAP还原能力、RP还原能力和TEAC总抗氧化能力最高。本研究为老黑谷米的开发利用提供科学依据。     

基于品质指标的苹果浊汁品种与产地差异性分析

以来自7?个不同主产区的21?个主栽品种,共41?份苹果鲜果为研究对象,对每个品种鲜榨浊汁的出汁率、浊度、果汁颜色、褐变度、透光率、可溶性固形物、可滴定酸、总酚、糖、有机酸、VC、矿物质、抗氧化性等品质指标进行测定。运用描述性分析、逐步线性判别分析进行数据处理。结果表明：不同品种或不同产地的苹果浊汁,品质差异较大。总体来看,a*值、原始浊度、褐变度、可滴定酸、葡萄糖、蔗糖、苹果酸等指标的变幅均较大,分别为94.07%、70.41%、42.86%、35.26%、42.02%、42.40%、37.69%。对于不同品种的苹果浊汁,由于褐变度、总酚、抗氧化性等色泽品质指标以及糖、酸等营养品质指标间具有较大差异,其分布呈现分散状态。其中新红星品种的褐变度、总酚含量、DPPH自由基清除率等品质指标普遍居高,色泽品质差异最显著。富士品种大部分样品的果糖、葡萄糖、蔗糖、苹果酸等指标含量较高,具有较好的营养品质。然而对于不同产地间的样品,其浊度、可滴定酸、可溶性固形物等加工品质指标具有较大差异,样品分布较为分散。河北省样品的出汁率、原始浊度、可滴定酸等指标普遍较低,加工品质较差。来自山东省不同品种苹果浊汁的样品以及来自不同产地富士苹果浊汁的样品间均具有较大差异,并且分别获得了77.8%和72.7%的判别准确率。以上结果表明,不同产地、不同品种苹果原料制得的苹果浊汁存在较大差异,通过对其品质指标进行差异性分析,可为上游育种与种植产业结构调整提供数据基础;通过判别模型的建立实现品种与产地的识别与预测,可以指导企业对苹果原料进行制汁专用化筛选。     

5种苹果微粉的理化品质与行为特征

为了制备高品质的苹果纯粉,给苹果制粉加工和新产品开发提供理论支持,以国家苹果种质资源圃中常见的5个加工兼鲜食苹果品种(长富2号、寒富、黄元帅、国光、秦冠)为原料,采用中短波红外干燥联合普通粉碎技术制备苹果微粉,对苹果微粉的理化指标及加工过程中的行为特征进行测定与分析,采用主成分分析法对苹果微粉的品质评价指标进行简化。结果显示,在理化指标方面,色泽上寒富苹果微粉的亮度显著高于其他品种苹果微粉,秦冠苹果微粉的亮度最小;长富2号微粉的总酚含量最高;富士系苹果微粉的总糖含量最高。在行为特征方面,长富2号和寒富在高应力条件下的黏结性较小且在输送过程中表现较好。对测定的20项指标依据主成分解释总变量和碎石图,从中提取了反映原来变量90.38%信息的3个主成分,综合各项指标得出富士系苹果是制备高品质苹果微粉的优选品种。     

不同品种苹果果实主要酚类物质含量的研究

用高效液相色谱仪测定了不同品种苹果果实绿原酸、儿茶素、表儿茶素、根皮素和槲皮素等主要酚类物质的含量。结果表明,不同品种苹果果肉酚类物质总量以富士和新红星最高,金冠最低。富士苹果果肉酚类物质以绿原酸为主,新红星和王林苹果果肉以表儿茶素为主。不同品种苹果果皮酚类物质总量以新红星最高,各品种苹果果皮酚类物质总量均高于果肉。果皮中酚类物质以黄烷-3-醇类为主。     

Quality Measurement of Intact and Fresh-cut Slices of Fuji, Granny Smith, Pink Lady, and GoldRush Apples

ABSTRACT: Development of fresh-cut apple products requires consideration of cultivars that store well as both intact and fresh-cut fruit. We compared the instrumental and sensory quality of 2 apple cultivars, Granny Smith and Fuji, that are used for fresh cutting with 2 new cultivars, Pink Lady and GoldRush, which were considered to have quality characteristics suitable for fresh cutting. Firmness, titratable acidity (TA), soluble solids content (SSC), and aromatic volatile concentration were measured in intact fruit of the 4 cultivars during 12 mo storage in air at 0 °C and during 3 wk storage at 5 °C as fresh-cut slices. After 1 wk storage as fresh-cut slices, sensory evaluations for acceptability of flesh and peel appearance, flavor, texture, and overall eating quality were performed. During storage, GoldRush apples maintained > 80 N firmness, approximately 17% SSC, > 0.5% TA, and had high aromatic volatile production, that is, maintained quality better than the other cultivars. The quality and shelf stability of GoldRush slices were also as good as or better than slices from the other cultivars, whereas Granny Smith slices generally rated lower than the other cultivars. The acceptability of flavor, texture, and overall eating quality of GoldRush slices was as good as that for Pink Lady and Fuji. The quality of GoldRush apples can be maintained throughout the year in refrigerated air storage and still remain suitable for fresh-cut processing. The results indicate that GoldRush and Pink Lady are 2 promising new, high-quality apple cultivars for fresh cutting. Keywords: fresh-cut fruit, Malus × domestica , postharvest quality, respiration rate, shelf life     

Changes of contents and antioxidant activities of polyphenols during fruit development of four apple cultivars

Polyphenols are functional components in apples and can be separated into four groups by Sephadex LH-20 as epicatechin, procyanidolic oligomers, chlorogenic acid and procyanidolic polymers. Antioxidant activities of each group were determined by FRAP and DPPH radical scavenging assay. It was found that procyanidolic oligomers and procyanidolic polymers influenced the total polyphenols content (measured by Folin–Ciocalteu method) much more in Jonagold, Golden Delicious, Fuji and Guoguang four apple cultivars. The Fe-reducing activity of procyanidolic oligomers in the four apple cultivars increased significantly during the development while the other three compounds changed irregularly. And the Fe-reducing activities of epicatechin and procyanidin contributed much more to the total Fe-reducing activities during the fruit development in the four apple cultivars. The DPPH scavenging activities of four compounds in Jonagold and Golden Delicious decreased during fruit development and that of Fuji and Guoguang changed irregularly. Chlorogenic acid was the main contributor in Jonagold, Golden Delicious and Fuji to the total scavenging activity. In Guoguang, it was procyanidolic oligomers that contributed much to the total scavenging activity.     

Apple Cultivar and Maturity Affect Haze-Active Protein and Haze-Active Polyphenol Concentrations in Juice

Juices were prepared from single apple cultivars in 3 crop years. The levels of haze‐active (HA) protein and HA polyphenol were much more similar in 1997 and 1998 than in 1996. Fuji had by far the highest HA protein while Spartan, Jonagold, and Monroe were intermediate. HA polyphenol levels were less consistent, but Empire, Liberty, and Monroe were low, and Jonamac, Jonagold, Golden Delicious, Cortland, and Ida Red were intermediate. The highest HA polyphenol was found in Rome. During fruit maturation, HA protein tended to increase while HA polyphenol declined. This led to a distinct tendency toward a lower HA polyphenol/HA protein ratio with time.     

新疆地区与黄河流域红富士苹果性状与品质分析

精选新疆地区、黄河流域16种红富士苹果,进行果实性状、营养成分分析和感官评价:新疆阿克苏、伊犁特克斯和陕西洛川的红富士苹果表现最佳。4地红富士苹果平均单果重甘肃陕西新疆山东,种群内变异性大(CV15%),具有显著性差异(p=00.05)。16种红富士苹果种群内部营养成分变异性较大(CV10%),尤其Vc、蛋白、膳食纤维(CV25%);不同产地间红富士还原糖(p=00.05)、可溶性固形物(p=0.05)、膳食纤维(p=0.0230.05)具有显著性差异。风味评分与固酸比之间具有显著正相关关系(p=00.05,r=0.886),新疆红富士具有更高的固酸比,且与其它地区具有显著性差异(p=0.0090.05),使得新疆红富士苹果更能满足人们对于风味的较高要求且与其它地区具有显著性差异(p=0.0030.05)。此外,还原糖与可溶性固形物具有显著正相关关系(p=0.0010.05,r=0.75),总酸和可溶性固形物之间存在显著正相关关系(p=0.0140.05,r=0.602)。     

INTEGRATING SENSORY ANALYSIS AND HEDONIC EVALUATION FOR APPLE QUALITY ASSESSMENT

ABSTRACT

Apple cultivars were subjected to a consumer test in order to appreciate individual preferences and set up a protocol for a practical hedonic‐sensory evaluation. Cultivars subjected to the test were “Golden Delicious,”“Modì,”“Pink Lady” and “Fuji” of two different origins. Apples had the sensory profile defined by a trained panel and were evaluated by 154 consumers. According to their preferences, consumer population could be divided in six clusters. Consumer preference responses clearly associated the two “Fuji” and showed “Modì” and “Pink Lady” to have appeal on the same consumers groups. Besides expressing hedonic judgment, consumers were requested to indicate the positive sensory attributes determining their choice. Consumers appreciated “Golden Delicious” and “Fuji” on the basis of sweetness and aroma, while preferences for “Pink Lady” and “Modì” were expressed by consumers appreciating crispness, juiciness and a certain degree of acidity. The involvement of consumers in defining attributes driving preferences provides details useful for weighing up the consistency between consumers' response and sensory panel profile.

PRACTICAL APPLICATIONS

This work contributes to the knowledge on consumer preferences and concerning apple sensory quality. In particular, the tested varieties could be divided in three groups on the basis of perceived attributes. Knowledge of consumer preferences related to apple qualities can be a key point in planning production and marketing strategies. A protocol integrating sensory characteristics defined by a trained panel, hedonic consumer judgments and sensory preference drivers is proposed.     

Nutraceutical potential of polyphenolic fractions from Annurca apple (M. pumila Miller cv Annurca)

The capacities of polyphenolic extracts from Annurca apple peel and flesh to inhibit the glucose and cholesterol uptake by HepG2 cells were evaluated, and compared with those of other conventional cultivars, such as Red Delicious (RD), Pink Lady (PL), Fuji (F) and Golden Delicious (GD). RD peels exhibited the best hypoglycaemic effects, while Annurca flesh appeared the most active in reducing cell cholesterol uptake among the cultivars tested. The influence of the apple polyphenolic extracts on the cell proliferation and oxidative stress was also evaluated. Particularly, RD, Annurca and PL peels decreased proliferation by a 62.5%, 48.0% and 37.5%, respectively, probably due to their prooxidant capacity. Conversely, flesh extracts appeared more protective of cells than peels: Annurca and RD, particularly, proved to be able of increasing proliferation by a 32.2% and 11.1%, respectively, probably due to their capacity of reducing cell physiological radical levels of a 33.3% and 19.9%, respectively.     

番木瓜果酒发酵及其抗氧化能力分析

以番木瓜为原料,经破碎、酶解、成分调整后接种葡萄酒活性干酵母,于（22±1） ℃发酵制备番木瓜果酒。研究发酵过程中总糖、还原糖、滴定酸含量与抗氧化能力的变化,明确番木瓜果酒的理化指标与感官品质。结果表明,番木瓜果酒发酵过程中总糖、还原糖含量逐渐降低,滴定酸含量增加,总酚含量、DPPH自由基清除率和亚铁还原能力（FRAP值）降低,pH值变化无规律性。番木瓜果酒酒精度10.7%vol,残糖量4.4 g/L,滴定酸4.5 g/L,总酚含量3.0 g/L,DPPH自由基清除率63.0%,FRAP值2.33 mmol/L,属半干型果酒,抗氧化能力较强,理化与感官品质均符合相关果酒标准要求。