邹运乾¹, 张立¹, 吴方方¹, 许让伟¹, 徐娟¹, 胡世全², 谢合平², 程运江^,11 华中农业大学园艺林学学院/国家柑橘保鲜技术研发专业中心/农业农村部园艺作物生物学与种质创制（果树）重点实验室/园艺植物生物学 教育部重点实验室,武汉 430070;
² 夷陵区农业技术推广中心,湖北宜昌 443100

Effects of Wax Coating on Off-Flavor Compound Accumulation in the Pulp of Satsuma Mandarin

ZOU YunQian¹, ZHANG Li¹, WU FangFang¹, XU RangWei¹, XU Juan¹, HU ShiQuan², XIE HePing², CHENG YunJiang^,11 College of Horticulture and Forestry Science, Huazhong Agricultural University/National R&D Center for Citrus Preservation, Key Laboratory of Horticultural Crop Biology and Germplasm Genetic Improvement (Fruit Crops), Ministry of Agriculture/Key Laboratory of Horticultural Plant Biology, Ministry of Education, Wuhan 430070;
² Agricultural Technology Extension Center of Yiling county, Yichang 443100, Hubei

通讯作者: 程运江,E-mail：yjcheng@mail.hzau.edu.cn

责任编辑: 赵伶俐
收稿日期:2019-12-10网络出版日期:2020-06-16

基金资助:

国家重点研发计划.2018YFD1000200 国家现代农业.柑橘产业技术体系CARS-26

Received:2019-12-10Online:2020-06-16
作者简介 About authors
邹运乾,E-mail：370058008@qq.com。










摘要
【背景】温州蜜柑（Citrus unshiu）是我国最重要的主栽鲜食宽皮柑橘,经洗果、打蜡、包装等采后商品化处理后,果肉异味物质快速积累,不仅影响果实口感、风味和消费者的购买选择,而且影响到果实的货架期和产品市场竞争能力。【目的】研究打蜡处理对温州蜜柑果实异味物质积累的影响,以期优化宽皮柑橘采后商品化处理技术和工艺,延长果实货架期,提高鲜果的市场竞争能力。【方法】以‘尾张’温州蜜柑成熟果实为试验材料,模拟生产中采用不同固体物含量的果蜡进行打蜡处理;扫描电镜观察各处理果实表面蜡质形态;气相色谱仪检测果实内部气体和异味物质含量;同时对光泽度、异味、风味、出汁量、满意度、甜度、酸度和总体满意度等消费者感官评价指标进行分析。【结果】打蜡处理能增加表面光泽度,同时使果实表面被人工合成蜡液覆盖,扫描电镜观察可见气孔被蜡液堵塞,果实内部O₂含量下降,CO₂含量上升。常温贮藏3周时,402D原液处理温州蜜柑果实内部CO₂浓度增加7.1%,比对照组增加1.0%;O₂浓度从1.6%降到1.4%。果肉乙醇和乙醛含量快速积累,产生异味,402D原液处理的果实内部乙醇含量1 773.8 mg·L^-1,商业果蜡（美国产402D果蜡）经过稀释可提高果心O₂含量,降低CO₂的含量,延缓果肉异味物质的积累速率。而1﹕1稀释后,果实内部乙醇含量560.5 mg·L^-1,感官评价由“高亮”到“较亮”,总体评价得分显著升高。果实打蜡处理后模拟低温冷链（4℃）贮运能有效抑制异味物质的积累,延长果实货架期。【结论】打蜡处理是导致温州蜜柑果实异味物质快速积累的关键原因,402D果蜡按1﹕1用水稀释后打蜡处理温州蜜柑果实在4℃下冷藏,能显著减少果肉异味物质积累,同时使果实货架期延长至4周。
关键词： 柑橘;异味;打蜡处理;感官评价;采后贮藏

Abstract
【Background】 Satsuma mandarin (Citrus unshiu) is the most important loose-skinned citrus fruit for fresh consumption in China. After washing, coating, packaging and other postharvest commercial handlings, the fruits often undergo a rapid accumulation of off-flavor compounds in the pulp, which obviously influences the taste and flavor and further affects the consumer's choice as well as the shelf life and market competitiveness of the fruit. 【Objective】 In order to optimize its postharvest commercial handling, the influence of waxing treatment on Satsuma mandarin was investigated, so as to prolong its shelf life and increase its market competitiveness. 【Method】 ‘Praecox Tanaka’ Satsuma mandarin fruits were treated with a series of dilutions of commercial waxes. Then, the internal CO₂ and O₂ content, ethanol and acetaldehyde concentrations and morphological changes of surface wax were monitored by GC-MS. In addition, the sensory attributes, including gloss, off-flavor, flavor, juiciness, mastication, sweetness, tartness and overall quality, were analyzed to comprehensively evaluate the effects of different treatments on fruit’s postharvest quality. 【Result】 The result showed that undiluted commercial wax T1 (402D) was able to increase the gloss of fruit surface, however, which could be detected clearly with scanning electron microscopy. The fruit surface was fully covered with artificial wax, which contributed to lower O₂ and higher CO₂ content. The internal content of CO₂ in undiluted 402D treated Satsuma mandarin fruit was increased by 7.1% when the fruits were stored for 3 weeks, and the O₂ content decreased from 1.6% to 1.4%. Compared to the control group, the content of CO₂ was increased by 1.0% in treated fruits. Waxing also led to a rapid accumulation of off-flavor compounds such as ethanol and acetaldehyde in the pulp, and dilution of the mother solution could increase O₂ content and decrease CO₂ content at the fruit core, as well as retard the accumulation rate of off-flavor compounds. It was further found dilution of 402D with water to a proportion of 1:1 could be rather effective, as we observed that the ethanol content was 1 773.8 mg?L^-1 in 402D treated fruits and the number lower to 560.5 mg?L^-1in 402D/H₂O (1:1) treated fruits. Also, the sensory evaluation changed from "highlighted" to "brighter", and the overall evaluation score increased significantly in 402D/H₂O (1:1) treated fruits. Besides, constant cold chain (4℃) after the coating treatment could effectively inhibit off-flavor compound accumulation and prolong the shelf life. 【Conclusion】 Coating treatment was the key reason for the rapid accumulation of off-flavor compounds in Satsuma mandarin fruit. When the fruit was treated with 402D/H₂O (1:1) and then stored at 4℃, the accumulation of ethanol and acetaldehyde, two typical odorous compounds, could be significantly reduced, which helped to greatly improve the taste and extend the shelf life to four weeks.
Keywords：mandarin;off-flavors compound;commercial wax;sensory evaluation;postharvest storage


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本文引用格式
邹运乾, 张立, 吴方方, 许让伟, 徐娟, 胡世全, 谢合平, 程运江. 打蜡处理对温州蜜柑果实异味物质积累的影响[J]. 中国农业科学, 2020, 53(12): 2450-2459 doi:10.3864/j.issn.0578-1752.2020.12.012
ZOU YunQian, ZHANG Li, WU FangFang, XU RangWei, XU Juan, HU ShiQuan, XIE HePing, CHENG YunJiang. Effects of Wax Coating on Off-Flavor Compound Accumulation in the Pulp of Satsuma Mandarin[J]. Scientia Acricultura Sinica, 2020, 53(12): 2450-2459 doi:10.3864/j.issn.0578-1752.2020.12.012

0 引言

【研究意义】柑橘作为我国南方地区最重要的水果产业,2018年全国柑橘产量已突破4 100万t（国家统计局统计结果）。与世界其他柑橘生产大国不同,我国温州蜜柑为主的宽皮柑橘约占总产量的2/3,且超过90%的果实用于鲜食^[1]。温州蜜柑具有丰产、优质等优点,但仍存在成熟期过度集中、果实不耐贮藏（一般2—4周）^[2,3]、商品化处理后异味物质快速积累导致货架期短等突出问题,直接制约了产业效益的提升。果实采后商品化处理涉及清洗、预分选、保鲜、打蜡、分级、包装、贮运等多道工序。在清洗过程中,柑橘果实表面的天然蜡质层受到损坏,会加速失水、缩短货架期,因此果实表面打蜡（涂膜）处理以补偿清洗对天然蜡质造成的损伤,显得尤为重要。研究表明,打蜡作为果实采后商品化处理的重要环节,不仅可以改善果实外观、减少果实水分散失,还可增强果实对采后病原微生物的抵抗力,降低果实采后腐烂率^[4]。但是,打蜡等商品化处理后果实易产生异味,丧失果实新鲜纯正的口感和风味^[5]。果蜡相关研究在美国、西班牙等柑橘生产大国开展较早,形成了系列果蜡专利产品,如美国DECCO公司“仙亮”“FMC”等系列果蜡、西班牙FOMESA公司的“威特”果蜡等。我国在果蜡领域的研究基础十分薄弱,生产中使用的果蜡产品主要依赖国外进口,其中美国以虫胶、树脂、脂肪酸盐为主要原材料生产的“仙亮”402D果蜡是我国温州蜜柑最常用的涂膜剂之一。但产区多年的使用结果表明,经402D打蜡处理的温州蜜柑果实4 h后就有明显的异味口感,而且随着存放时间延长,异味愈加浓烈,严重影响果实货架期和市场竞争力。【前人研究进展】涂抹剂用于食品保鲜最早可以追溯到12世纪的宋朝,人们在柠檬和橙子上涂抹脂质成分以达到减少失水的作用^[4]。16世纪,食品被涂上脂肪（如猪油）以减少失水,20世纪30年代石蜡、棕榈蜡和乳化油水涂层被用于新鲜水果和蔬菜保鲜^[6]。此后涂膜剂被广泛用来防止果蔬采后失水并增加其表面光泽度,如海藻酸钠涂膜处理能够显著降低水蜜桃果实的腐烂率,抑制其呼吸作用,维持果实硬度、延缓丙二醛含量的上升^[7];也能够提高芒果的抗氧化水平^[8]。羟丙基甲基纤维素和蜂蜡的涂层可抑制番石榴‘Pedro Sato’成熟,并延长其货架期6 d以上^[9]。壳聚糖打蜡处理建阳橘柚能防止病原微生物的侵染,减少病害的发生,保持较高的商品价值^[10]。姜黄素保鲜剂打蜡处理沙糖橘贮藏80 d结果表明,其果实腐烂率和失重率均显著低于对照^[11]。王日葵等^[12]用果蜡处理的夏橙和锦橙果实外观品质均明显地得到提高,402D果蜡处理最好。402D处理芦柑25 d出现酒精味,35 d之后,酒精味加浓,而且还出现其他异味^[13]。生产中,温州蜜柑与其他柑橘类型相比更易产生和积累异味,温州蜜柑等宽皮柑橘经市场销售的商业果蜡打蜡处理后,乙醇和乙醛快速积累,形成异味口感,果实的商品性能显著降低^{[14,15,16,17]}。研究表明温州蜜柑比葡萄柚果皮的气体交换和渗透率更低,而且乙醇脱氢酶的活性更高,推测这可能是温州蜜柑不耐贮性的重要原因^[18]。【本研究切入点】我国对柑橘采后打蜡处理缺乏系统的研究,没有技术规范;温州蜜柑种植规模大,成熟期早,采后品质保持困难,严重制约了产业效益提升。【拟解决的关键问题】以生产中常用的402D果蜡为参照,通过稀释改变果蜡固体物含量,研究不同固体物含量的果蜡处理温州蜜柑对果实内部O₂、CO₂、乙醇和乙醛的含量,果实表面特性及消费者感官品质变化的影响,为优化温州蜜柑打蜡工艺和改善果实商品化处理后贮运条件,延长果实货架期,提升产品市场竞争能力提供理论依据。

1 材料与方法

试验于2013—2014及2017年在湖北武汉华中农业大学园艺植物生物学教育部重点实验室进行。

1.1 供试材料

‘尾张’温州蜜柑（Citrus unshiu Marc）采自湖北省宜昌市夷陵区的生产果园,树龄约20年,果实均达到商业采收的成熟标准,选取无病虫害、无机械损伤、无明显果面瑕疵、大小色泽一致的果实为试验材料。每次采摘约200 kg,重复取样3年。

供试蜡液为市场销售的美国402D商业果蜡（Decco, Cerexagri Inc.美国）。

1.2 样品处理

为研究不同固体物含量的果蜡打蜡处理对温州蜜柑果实异味物积累的影响,进行以下4组处理：T₁：未经稀释的402D果蜡原液（固体物含量约20%）;T₂：402D果蜡与水1﹕1稀释液（固体物含量约10%）;T₃：402D果蜡与水1﹕3稀释液（固体物含量约5%）;T₄：对照组,直接用清水将果实清洗干净。温州蜜柑果实用清水清洗后晾干,模拟实际生产进行打蜡处理,每吨果实平均用蜡量约为1.4 L。各处理的果实用量约50 kg,打蜡后自然晾干。模拟常温（20℃,相对湿度70%—75%）和冷链（4℃,相对湿度90%—95%）环境,观察果实货架期。常温货架果实每隔1周取1次样,共3次。冷库贮藏为了更好的模拟实际生产,不同打蜡处理后的果实在常温下分别存放0、1、2和4 d（分别标记为T_n 0 d、T_n 1 d、T_n 2 d、T_n 4 d,n=1/2/3）后转冷库贮藏4周,再转常温贮藏1周,分别在冷库贮藏4周及冷库贮藏4周并常温贮藏1周后取样测定相关指标。

1.3 果皮的扫描电镜观察

参照吴方方^[19]的方法：用pH 7.2的磷酸盐缓冲液清洗各个处理果实表面。用手术刀片切果皮0.3 cm×0.2 cm的小片状有色层。2.5%戊二醛固定24 h,脱水：乙醇系列30%-50%-70%-85%-95%-100%（2次）逐级脱水,直至脱水干净。换取中间液,临界点干燥,离子溅射仪镀膜后入镜观察。每个处理帖2片,用电子扫描显微镜（NTC JSM-6390LV,日本）100×、1 000×、1 500×、3 000×观察果皮表面状况及气孔,赤道部选4个点做统计观察。

1.4 果实内部CO₂和O₂含量测定

将不同处理待测果实在烧杯中完全浸于水中,用气密针从果蒂插入果实中柱鞘部位抽取0.5 mL果实内部气体,然后注入气相色谱仪（美国Agilent7890A）。测定条件为：CTR-1填充柱,柱温40℃,TCD检测器温度120℃,每个处理重复3次。

1.5 乙醇、乙醛含量测定

参照吴方方^[19]的方法：每3个果实取5 mL果汁,置于10 mL气相色谱专用小瓶中,80℃下水浴15 min后,用气密针取1 mL色谱专用小瓶中顶空气体注入气相色谱仪（美国 Aglilent7890A）。测定条件为：使用DB624毛细管色谱柱,柱温40℃,火焰离子检测器（FID）温度250℃,进样口温度250℃,载气为H₂,恒压,载气流速30 mL?min^-1,分流比1﹕10,每个处理重复3次。

1.6 感观评价

参照何义仲等^[20]的方法,随机招募20名志愿者组成感官评价的测试人员,每次评价时不同处理组以及对照随机选取5个果实做好标记,先目测打分。评价指标包括光泽度、甜度、酸度、异味、风味、出汁率、化渣性、总体满意度,感官评价试验均按0—4级打分,评分标准为5级,其中,0：无;1：轻微;2：一般;3：偏高;4：极高。以总体满意度作为消费者感官评价的最终结果,得分越高说明消费者对果实认可度越高,品质越好。

1.7 数据处理

用Excel 2003处理数据,应用SAS软件ANOVA作差异显著性分析（P<0.05）。

2 结果

2.1 打蜡处理对果皮表面形态的影响

从扫描电镜观察的结果来看,T₁处理温州蜜柑果实后,果皮表面气孔被完全覆盖,裂缝较少,气孔堵塞严重;T₂或T₃处理时,果皮表面气孔被果蜡部分堵塞,T₄组处于完全开放状态（图1）。表明高固体物含量的402D果蜡原液对果面气孔的堵塞,会直接影响果实与环境的气体交换。

图1

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图1不同固体物含量的果蜡处理对‘尾张’温州蜜柑果皮表面形态的影响

A、E：T₁处理（固体物含量20%）;B、F：T₂处理（固体物含量10%）;C、G：T₃处理（固体物含量5%）;D、H：T₄处理（固体物含量为0）
Fig. 1Effects of different solid contents of waxing treatment on the surface morphology of ‘Praecox Tanaka’ satsuma mandarin fruit

SEM pictures of the epidermis and stomata of A, E: T₁ (solid content of 20%); B, F: T2 (solid content of 10%); C, G: T₃ (solid content of 5%); D, H: T₄ (solid content of 0%) coated fruits

2.2 打蜡处理对果实内部O₂和CO₂含量的影响

果实内部气体含量检测结果表明,无论是短期常温贮藏还是长期冷藏,打蜡处理后的温州蜜柑果实内部CO₂含量呈上升趋势,O₂含量均呈下降趋势,402D原液稀释后处理能够减缓这种变化趋势。常温贮藏条件下,T₁处理组CO₂浓度从第1周8.4%上升到第3周15.5%（图2）。T₂处理CO₂浓度从第1周的5.7%上升到第3周的7.1%,而对照组CO₂浓度从第1周1.3%仅上升到第3周2.3%,且随着贮藏时间的延长,果实内部CO₂浓度逐渐升高。O₂含量则逐渐降低,T₁处理组O₂浓度从第1周的1.6%下降到第3周1.4%（图2）,而对照组O₂浓度从第1周15.1%下降到第3周13.2%。冷藏条件下,果蜡的固体物含量与打蜡处理后果实转移到冷库的时间间隔对果实中柱空腔内气体浓度均有明显影响。从图2可以看出,固体物含量为20%的402D原液打蜡后即转移到冷库贮藏（T₁,0 d）时CO₂为6.1%,O₂含量为1.4%。对照组（T₄,0 d）果实4℃冷藏4周内果实中柱空腔内部CO₂的浓度为2.7%,O₂浓度为13.1%,固体物含量为20%的402D原液打蜡后常温下放置4 d再转移到冷库的处理（T₁,4 d）CO₂为8.18%,O₂含量为1.4%。冷库贮藏前常温放置的时间越长,冷库贮藏果实内部CO₂含量越高。

图2

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图2不同固体物含量的果蜡处理‘尾张’温州蜜柑对果实内部CO₂和O₂的含量的影响

A：常温贮藏果实内部CO₂含量;B：低温贮藏后转常温贮藏果实内部CO₂含量;C：常温贮藏果实内部O₂含量;D：低温贮藏后转常温贮藏果实内部O₂含量。不同小写字母代表同一时间节点不同处理间统计检验在5%水平差异显著,*代表同一处理下不同时间节点间统计检验在5%水平差异显著
Fig. 2Effects of different solid content of waxing treatments on the contents of CO₂ and O₂ in ‘Praecox Tanaka’ satsuma mandarins fruits

A: Internal CO₂ concentration of ‘Praecox Tanaka’ Satsuma mandarins stored under normal temperature; B: Low temperature and then transferred to normal temperature; C: Internal O₂ concentration of ‘Praecox Tanaka’ satsuma mandarins stored under normal temperature; D: Low temperature storage and then transferred to normal temperature. Different lowercase letters represent significant differences at 5% level between different solid content of waxing treatments under the same time point, * represent statistically significant differences at 5% level at different time point


模拟市场销售的货架期,将冷藏温州蜜柑果实转移到常温下1周,部分处理组果实内部O₂含量略上升,CO₂含量略下降,这可能与果实内部气体含量和由环境封闭冷库贮藏转移到自然环境后,果实内外气体能更好地进行交换有关。

2.3 打蜡处理对果实乙醇和乙醛含量的影响

低固体物含量的402D果蜡处理的温州蜜柑果实转移到冷库的时间越早,果实内积累的乙醇、乙醛等异味物质含量越低。乙醇和乙醛是果实无氧呼吸产生的代谢物,是果实采后贮藏过程中形成异味的主要物质。打蜡处理与冷藏的时间间隔对果实异味物质的积累有显著的影响。结果表明,打蜡果实中乙醇和乙醛含量显著高于对照,且随着贮藏时间的延长而增加（图3、4）。常温下贮藏3周后,T₄组乙醇含量为777.9 mg?L^-1,而T₁组的果实乙醇含量高达2 899.3 mg?L^-1;伴随着402D果蜡固体物含量由20%降低到5%,果实内部的乙醇含量降低到1 415.4 mg?L^-1,乙醛含量由27.34 mg?L^-1降低到14.07 mg?L^-1,并且与图2中第3周402D蜡液处理果实内部CO₂含量的升高趋势相同,由于CO₂的积累,无氧呼吸加剧导致乙醇、乙醛等异味物质大量累积。上述结果表明,打蜡处理后及时转入低温贮藏,有利于降低乙醇和乙醛的浓度,延缓异味形成。

图3

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图3不同固体物含量果蜡处理对‘尾张’温州蜜柑果实乙醇含量的影响

A：常温贮藏不同处理乙醇含量;B：冷库贮藏T₁（固体物含量20%）与对照处理乙醇含量;C：冷库贮藏T₂（固体物含量10%）与对照处理乙醇含量;D：冷库贮藏T₃（固体物含量5%）与对照处理乙醇含量。不同小写字母表示同一时间不同处理间差异显著（P<0.05）。下同
Fig. 3Effects of different solid content of waxing treatments on the contents of alcohol in ‘Praecox Tanaka’ satsuma mandarins

A: Ethanol contents in the juice under different treatments stored at room temperature; B: Ethanol content of fruits treated with T₁ (solid content of 20%) and control in cold storage; C: Ethanol content of fruits treated with T₂ (solid content of 10%) and control in cold storage; D: Ethanol content of fruits treated with T₃ (solid content of 5%) and control in cold storage. Different lowercase letters indicate significant difference among different treatments at the same time (P<0.05). The same as below

图4

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图4不同蜡液处理对‘尾张’温州蜜柑果实乙醛含量的影响

A：常温贮藏不同处理乙醛含量;B：冷库贮藏T₁（固体物含量20%）与对照处理乙醛含量;C：冷库贮藏T₂（固体物含量10%）与对照处理乙醛含量;D：冷库贮藏T₃（固体物含量5%）与对照处理乙醛含量
Fig. 4Effects of different solid content of waxing treatments on the contents of alcohol in ‘Praecox Tanaka’ Satsuma mandarins fruits

A: Acetaldehyde contents in the juice under different treatments and storage at room temperature; the higher the solid content is, the higher the acetaldehyde content in fruit will be; B: acetaldehyde content of fruits treated with T₁ (The solid content is 20%) and control in cold storage; C: Acetaldehydel contents of fruits treated with T₂ (The solid content is 10%) and control in cold storage; D: Acetaldehyde contents of fruits treated with T₃ (The solid content is 5%) and control in cold storage


4℃冷藏4周后,不同固体物含量的402D果蜡处理的果实内部乙醇、乙醛含量之间差异不显著,但当转移到常温下放置1周（模拟果实货架期）后,乙醇、乙醛等异味物质含量急剧增加,T₁处理的果实内部乙醇含量显著积累,由470.6 mg?L^-1增加到1 773.8 mg?L^-1,而T₂组则由396.2 mg?L^-1增加到560.5 mg?L^-1,说明适当降低果蜡固体物含量有助于减少异味物质的积累。

2.4 打蜡处理对果实感官品质的影响

消费者感官评价的结果表明,常温贮藏3周,T₂处理过的温州蜜柑虽然亮度比T₁处理的低,但对维持有机酸的水平,延缓异味物质的积累具有明显的效果（图5）。由图5可看出,亮度由‘高亮’到‘较亮’;在异味方面,T₁处理异味最明显,随着固体物含量的降低,异味分降低,由‘强烈异味’到‘适度异味’;在风味方面,T₃和T₂相比T₁处理的风味更强。总体来看,不同固体物含量的果蜡处理在温州蜜柑果实的光泽度、异味、风味、酸度方面差异显著,在甜度、出汁率、化渣性等方面差异不显著。贮藏4周,从总体评价来看,与常温下感官评价的结果一致,T₂处理效果最好（表1）。上述结果表明,打蜡能够显著提高温州蜜柑果皮亮度,且固体物含量越高,果实亮度越高;但降低蜡液固体物含量,果实异味含量降低,风味、化渣性、出汁率和满意度随之增高。

图5

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图5打蜡和对照‘尾张’温州蜜柑果实的感官评价

Fig. 5Sensory attributes of wax-coated and -uncoated ‘Praecox Tanaka’ satsuma mandarins after three weeks of storage at room temperature



Table 1
表1
表1‘尾张’温州蜜柑果实的感官评价
Table 1Sensory attributes of wax-coated and -uncoated ‘Praecox Tanaka’ satsuma mandarins

	异味值 Off-flavor		光泽度 Gloss		酸度 Tartness		甜度 Sweetness		出汁量 Juiciness		风味 Flavor		化渣性 Mastication		总体评价 Overall quality
	4℃*	20℃**	4℃	20℃	4℃	20℃	4℃	20℃	4℃	20℃	4℃	20℃	4℃	20℃	4℃	20℃
T1 0 d	2.31c	2.47c	3.81d	3.20d	1.81a	2.53c	1.88a	1.60a	2.25a	2.27a	1.13a	1.20a	2.63a	1.87a	3.45b	1.42b
T1 1 d	1.81b	2.40c	3.81d	3.07d	2.13b	2.40c	1.88a	2.00b	2.19a	2.27a	1.38a	1.73b	2.50a	1.87a	3.23ab	1.47b
T1 2 d	2.06b	3.60d	3.00c	2.33b	1.56a	2.60c	2.44c	1.33a	2.44a	2.27a	1.25a	1.07a	2.44a	2.07ab	3.12b	1.33b
T1 4 d	1.50ab	2.53c	2.50b	2.27b	1.88b	1.60a	2.19a	2.00b	2.63b	2.27a	1.69ab	1.40ab	2.44a	2.13b	2.78a	1.06a
T2 0 d	1.38a	1.93b	2.50b	2.27b	2.25b	2.13b	1.94a	1.93b	2.63b	2.33a	2.00bc	1.53ab	2.31a	1.93a	4.11c	3.58d
T2 1 d	2.06b	1.40a	2.81b	2.67c	1.75a	1.53a	2.25b	2.20b	2.19a	2.60b	1.25a	1.60b	2.38a	2.20b	3.56b	3.28cd
T2 2 d	1.50ab	1.93b	2.56b	2.53c	1.94b	1.67a	1.94a	2.33b	2.25a	2.40ab	1.75b	1.67b	2.25a	2.13ab	3.53b	2.76c
T2 4 d	1.38a	2.26c	1.56a	1.80a	1.69a	1.67a	2.50c	2.33b	2.63b	2.53b	2.25c	1.47ab	2.25a	2.20b	3.14ab	2.33bc
T3 0 d	1.31a	1.53ab	2.50b	2.60c	1.94b	2.20a	2.06ab	2.13b	2.69b	2.53b	1.81a	1.87b	2.38a	2.27b	3.78bc	3.13cd
T3 1 d	1.56ab	1.47a	2.44b	2.60c	1.69a	2.00b	2.13ab	2.00b	2.31a	2.60b	1.56ab	1.80b	2.38a	2.40c	3.88bc	3.14cd
T3 2 d	1.06a	1.33a	2.38b	2.33b	2.13b	2.07b	2.25b	2.27b	2.63b	2.53b	2.19c	2.13bc	2.38a	2.00ab	3.57b	2.38bc
T3 4 d	1.56ab	1.33a	2.38b	2.00ab	1.69a	2.00b	1.88a	2.33b	2.31a	2.20b	1.31a	1.93b	2.31a	2.20b	3.23ab	2.16bc
T4	1.19a	1.00a	1.50a	1.67a	2.13b	1.67a	2.06ab	3.00c	2.63b	2.73c	2.13c	2.40c	2.25a	2.27bc	3.87bc	2.33bc

*: Cold storage for 4 weeks; **: Cold storage for 4 weeks and then transfer to normal temperature storage for 1 week
*：冷库贮藏4周;**：冷库贮藏4周后转常温贮藏1周

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4℃冷藏4周,果蜡固体物含量对温州蜜柑果实的光泽度影响较大,但对果实的异味、酸度、甜度、风味等品质性状无显著影响（表1）。T₁处理后即刻转入冷库（T₁ 0 d）亮度评分均为3.81,T₂、T₃处理后即刻转入冷库亮度评分为2.50,T₄处理为1.19。打蜡处理后,果实在转入冷库前常温下放置的时间越长,亮度越低,感官评价反映异味越浓,总体评价越低,T₁处理后即刻转入冷库亮度评分为3.81,常温放置4 d再转入冷库（T₁ 4 d）亮度评分则为2.50。总体评价最高为T₂处理后立即转入冷库（T₂ 0 d）贮藏组,平均评分4.11;最低为T₁处理后常温放置4 d再转入冷库贮藏组（T₁ 4 d）,平均评分2.78。模拟销售时的货架条件,将不同处理的果实从冷库转移到常温下1周后（表1）,其中T₁处理异味打分明显增加,由‘轻度异味’到‘适度异味’或‘强烈异味’,T₁ 0 d异味评价得分从2.31到2.47,T₁第4天异味评价得分从1.50到2.53,T₂ 0 d异味评价得分从1.38到1.93。总评价也变差,T₁ 0 d总体评价得分从3.45到1.42,T₁第4天总体评价得分从2.78到1.06,T₂ 0 d总体评价得分从4.11到3.58,说明冷库贮藏后转入常温使果实异味物质积累显著,总体评价显著降低。

3 讨论

402D果蜡是我国温州蜜柑采后商品化处理中最常用的涂膜剂之一,采用402D打蜡处理我国温州蜜柑后引起的异味物质积累加速、果实表皮褐变、内部品质下降等问题十发突出。柑橘果实采后商品化处理过程中,打蜡处理使果实表面被人工合成蜡液覆盖,从而增加果实表面光泽度。但是打蜡处理在改善果实表面光泽度的同时也影响到果实与环境的气体交换^[21],果实内部会逐步积累呼吸代谢产生的CO₂,常温贮藏3周,402D原液处理温州蜜柑果实内部CO₂浓度增加7.12%;O₂浓度降低到1.4%。固体物含量越高,蜡液黏度越大,附着于果实表面的蜡液也越多,厚度越厚。蜡液厚度与果实内部气体的变化有直接的关系,从而影响果实内部呼吸方式的变化。当果实内部O₂含量低于果实有氧呼吸所需O₂的阀值,CO₂含量高于果实忍耐极限值时,果实就会发生无氧呼吸导致品质下降^[22]。

乙醇和乙醛是一种增加果实风味的前体物质,但乙醇含量高于1 500 mg?L^-1时就会降低果实风味,产生一种‘酒糟’异味^[23]。伴随无氧呼吸产生的乙醇和乙醛的不断积累,加剧了柑橘果实‘酒糟’异味的产生。402D原液处理3周时乙醇含量2 899.3 mg?L^-1,乙醛含量27.34 mg?L^-1,品尝试验结果表明风味评分为1.6,稀释至1/4浓度时乙醇含量降低一半,风味评分2.7。说明固体物含量越高,果实透气性越差,而透气性较差的果蜡处理的果实在常温贮藏条件下,代谢加快,糖酸含量降低,总体风味变淡。

固体物含量高的（402D原液）处理果实亮度最高,降低蜡液固体物含量导致打蜡果实亮度降低的同时果实中的异味物质含量也明显降低。试验表明固体物含量的降低会导致果实失重率增加,但CO₂、乙醇、乙醛等物质透过率增大。402D原液处理亮度评分2.8,稀释至1/2浓度后评分为2.1,总体评价由1.7增至2.5。本研究结果和美国、西班牙、以色列等柑橘生产大国的生产经验均表明,打蜡是柑橘采后商品化过程中必不可少的重要环节,但果蜡的选择必须考虑柑橘品种和产区气候特点,各柑橘生产大国均针对本国主栽柑橘品种研发了专用果蜡配方。因此,根据我国柑橘果面天然蜡质生物学特点,开发品种特异性的专用果蜡产品对提高我国柑橘采后商品化处理的技术水平具有重要意义。

温州蜜柑果实采收季节气温较高,果实经打蜡等商品化处理后,尽快进入低温冷链环境（4℃）,可有效抑制果实的失重和异味物质积累。相比常温贮藏（20℃）,4℃冷藏条件下不同浓度果蜡处理的温州蜜柑果实内部乙醇和乙醛含量都有所下降,有利于贮藏后期果实的品质保持,延长销售货架期。但冷库贮藏果实转移到常温1周后,果实无氧呼吸加剧,乙醇和乙醛含量迅速积累。改善果蜡的透气性是延缓果实中异味物质积累的有效途径,根据现有的打蜡生产工艺,结合冷链和冷贮藏也是解决该问题的有效方法^[24,25,26]。但是,一旦中途冷链环境受到破坏,则会导致果实异味的快速积累。此外,降低现有果蜡固体物的含量,改善果面透气性也可达到控制果实异味的效果,但生产中会增加打蜡后烘干环节的能耗。

4 结论

高固体物含量的402D果蜡处理温州蜜柑阻隔了果实内外气体的交换,导致CO₂积累,O₂浓度降低,从而加剧果实的无氧呼吸,导致乙醇、乙醛等异味物质积累。高固体物含量的402D果蜡是引起温州蜜柑商品化处理后异味物质快速积累的直接原因,对402D进行1﹕1稀释且打蜡后快速预冷,结合全程冷链可有效缓解果实异味积累。

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[7] 刘影, 李晓宇, 杜小龙, 邹萌萌, 张静静, 李建龙. 不同涂膜处理对水蜜桃常温贮藏品质的影响
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[本文引用: 1]

LIU Y, LI X Y, DU X L, ZOU M M, ZHANG J J, LI J L. Effects of different coating treatments on the storage of honey peach
Food Research and Development, 2019,40(12):1-5. (in Chinese)
[本文引用: 1]

[8] RASTEGAR S, KHANKAHDANI H H, RAHIMZADEH M. Effectiveness of alginate coating on antioxidant enzymes and biochemical changes during storage of mango fruit
Food Biochemistry, 2019. doi: 10.1111/jfbc.12990.
DOI:10.1021/acs.biochem.8b01080URLPMID:30383375 [本文引用: 1]
Replication of nucleic acids in the absence of genetically encoded enzymes represents a critical process for the emergence of cellular life. Repeated separation of complementary RNA strands is required to achieve multiple cycles of chemical replication, yet thermal denaturation under plausible prebiotic conditions is impaired by the high temperatures required to separate long RNA strands and by concurrent degradation pathways, the latter accelerated by divalent metal ions. Here we show how the melting temperature of oligoribonucleotide duplexes can be tuned by changes in pH, enabling the separation of RNA strands at moderate temperatures. At the same time, the risk of phosphodiester bond cleavage is reduced under the acid denaturation conditions herein described, both in the presence and in the absence of divalent metal ions. Through a combination of ultraviolet and circular dichroism thermal studies and gel electrophoresis, we demonstrate the relevance of geological pH oscillations in the context of the RNA strand separation problem. Our results reveal new insights in the field of prebiotic chemistry, supporting plausible geochemical scenarios in which non-enzymatic RNA replication might have taken place.

[9] FORMIGA A S, JUNIOR J S P, PEREIRA E M, CORDEIRO I N F, MATTIUZ B H. Use of edible coatings based on hydroxypropyl methylcellulose and beeswax in the conservation of red guava ‘Pedro Sato’
Food Chemistry, 2019,290:144-151.
DOI:10.1016/j.foodchem.2019.03.142URLPMID:31000030 [本文引用: 1]
Guavas are tropical climacteric fruit with a short postharvest shelf life at room temperature. This study aims to extend the shelf life of red guavas 'Pedro Sato' using edible coatings of hydroxypropyl methylcellulose (HPMC) and beeswax (BW) at concentrations of 10%, 20%, and 40% (dry basis). Coated and uncoated guavas were stored for 8days at 21 degrees C and assessed every 2days. The HPMC+BW produced a modified atmosphere around the fruit, delaying ripening process. The coatings reduced loss of mass, maintained green color, and increased firmness compared to the control fruit. The uncoated fruit had 6days of shelf life. The treatment with HPMC+20% BW provided the best maintenance of fruit quality. On the eighth day, fruit with this coating showed the same physicochemical characteristics of control fruit in the second day of storage, which represents a gain of 6days in the shelf life of guavas 'Pedro Sato'.

[10] 纪颖, 林河通, 蒋璇靓, 黄华明, 李娜, 肖烟云. 壳聚糖处理对采后建阳桔柚果实品质和贮藏特性的影响
热带作物学报, 2019,40(4):758-765.
[本文引用: 1]

JI Y, LIN H T, JIANG X L, HUANG H M, LI N, XIAO Y Y. Effects of different concentrations of chitosan treatment on quality attributes and storage behavior of harvested ‘Jianyang Tangelo’ fruit
Chinese Journal of Tropical Crops, 2019,40(4):758-765. (in Chinese)
[本文引用: 1]

[11] 司徒满泉, 吴成见, 康益轩, 赖健. 姜黄素保鲜剂对采后沙糖橘保鲜效果研究
现代食品, 2019(8):9-12, 16.
[本文引用: 1]

SITU M Q, WU C J, KANG Y X, LAI J. Storage effects of curcumin antistaling agent on post-harvest Sugar orange
Modern Food, 2019(8):9-12, 16. (in Chinese)
[本文引用: 1]

[12] 王日葵, 邵蒲芬, 周炼, 朱让果. 涂蜡对柑橘生理变化及商品性的影响
保鲜与加工, 2005,5(2):21-22.
[本文引用: 1]

WANG R K, SHAO P F, ZHOU L, ZHU R G. Effect of waxing on physiology and merchandise of citrus
Storage and Process, 2005,5(2):21-22. (in Chinese)
[本文引用: 1]

[13] 王玉玲, 蓝炎阳. 三种果蜡在芦柑保鲜的应用研究
福建热作科技, 2012(3):18-21.
[本文引用: 1]

WANG Y L, LAN Y Y. Study on the application of three kinds of fruit wax in the preservation ofCitrus mandarin
Fujian Science & Technology of Tropical Crops, 2012(3):18-21. (in Chinese)
[本文引用: 1]

[14] COHEN E, SHALOM Y, ROSENBERGER I. Postharvest ethanol buildup and off-flavor in ‘Murcott’ tangerine fruits
Journal of the American Society for Horticultural Science, 1990,115:775-778.
DOI:10.21273/JASHS.115.5.775URL [本文引用: 1]

[15] TIETEL Z, BAR E, LEWINSOHN E, FELDMESSER E, FALLIK E, PORAT R. Effects of wax coatings and postharvest storage on sensory quality and aroma volatile composition of ‘Mor’ mandarins
Journal of the Science of Food and Agriculture, 2010,90:995-1007.
DOI:10.1002/jsfa.3909URLPMID:20355140 [本文引用: 1]
BACKGROUND: Mandarins suffer from accumulation of off-flavours after harvest. In this study the sensory quality and aroma profile composition of homogenised segments of untreated (control) and wax-coated 'Mor' mandarins after 7 days at 20 degrees C or 3 or 6 weeks of cold storage at 5 degrees C were examined. RESULTS: Fruit taste score decreased during storage and following wax coating, and this was attributed to decreases in sourness and mandarin flavour and accumulation of off-flavours. Aroma profiling identified 31 volatiles that decreased by at least 50% during storage and after waxing and thus may be involved in the observed flavour loss. In contrast, 13 volatiles, mostly belonging to ethanol fermentation and fatty acid and amino acid catabolism pathways, significantly increased at least twofold and probably contributed to off-flavour enhancement. CONCLUSION: The results showed that after harvest there was a progressive decrease in sensory quality of 'Mor' mandarins. It is proposed that observed decreases in contents of sesqui- and monoterpenes and short-chain oxygenated fatty acids may contribute to the decrease in mandarin flavour, whereas increases in the contents of ethanol fermentation metabolites and derivates of fatty acid and amino acid catabolism are most likely involved in causing the enhanced sensation of off-flavours.

[16] OBENLAND D, COLLIN S, MACKEY B, SIEVERT J, ARPAIA M L. Storage temperature and time influences sensory quality of mandarins by altering soluble solids, acidity and aroma volatile composition
Postharvest Biology and Technology, 2011,59:187-193.
DOI:10.1016/j.postharvbio.2010.09.011URL [本文引用: 1]
Mandarins are very prone to losing flavor quality during storage and, as a result, often have a short shelf life. To better understand the basis of this flavor loss, two mandarin varieties ('W. Murcott' and 'Owari') were stored for 0, 3 and 6 weeks at either 0 degrees C, 4 degrees C, or 8 degrees C plus 1 week at 20 degrees C, and then evaluated for sensory attributes as well as quality parameters and aroma volatile profile. The experiment was conducted multiple times for each variety over two seasons, using three separate grower lots per experiment. Flavor quality was reduced in 'Owari' following 4 weeks of storage as off-flavor increased, while for 'W. Murcott' the hedonic score decreased after the fruit were stored for 7 weeks. Sensory panelists also noted a decline in tartness during storage for both varieties that was associated with an increase in the ratio of soluble solids concentration (SSC) to titratable acidity (TA). Large increases in alcohols and esters occurred during storage in both varieties, a number of which were present in concentrations in excess of their odor threshold values and are likely contributing to the loss in flavor quality. Thirteen aroma volatiles, consisting mainly of terpenes and aldehydes, declined during storage by up to 73% in 'Owari', only one of which significantly changed in 'W. Murcott'. Although many of these volatiles had aromas characteristic of citrus, their involvement in flavor loss during storage is unclear. 'W. Murcott' stored at 8 degrees C had slightly superior flavor to fruit stored at either 0 degrees C or 4 degrees C, and the better flavor was associated with higher SSC/TA and lesser tartness. Aroma volatiles did not play a role in the temperature effect on flavor as there were no significant differences in volatile concentrations among the three temperatures. There was no effect of storage temperature on the flavor of 'Owari'. Published by Elsevier B.V.

[17] TIETEL Z, LEWINSOHN E, FALLIK E, PORAT R. Importance of storage temperature in maintaining flavor and quality of mandarins
Postharvest Biology and Technology, 2012,64:175-182.
DOI:10.1016/j.postharvbio.2011.07.009URL [本文引用: 1]
Mandarins suffer from short 'flavor-life' compared with other citrus species. The recommended minimum safe temperature for mandarin storage is 5-8 degrees C. However, because of continuing reductions in permitted chemical residues and increasing concern regarding decay development, mandarins are often shipped at much lower temperatures of 3-4 degrees C. In the last few years we noticed wide differences in responsiveness of mandarin varieties to chilling, and that the earliest indication of damage was a decrease in flavor acceptability. In the present study, we evaluated changes in flavor and quality of chilling-tolerant 'Or' and chilling-sensitive 'Odem' mandarins after 4 weeks of storage at 2, 5, or 8 degrees C followed by 3 days at 20 degrees C. Low storage temperatures resulted in loss of orange peel color in fruit of both varieties, which became paler and yellowish. The flavor of 'Or' mandarins was not affected by different storage temperatures, whereas 'Odem' showed severe flavor loss at low storage temperatures. GC-MS analysis of aroma volatiles revealed that changes of storage temperatures had no major effects on aroma volatile contents in 'Or' mandarins. However, in 'Odem' mandarins, storage at 2 degrees C caused accumulation of 13 volatiles, mainly terpenes and their derivates, whereas storage at 8 degrees C resulted in decreases of six volatiles, comprising five terpenes and one terpene derivative. Overall, we conclude that storage temperature is a fundamental factor affecting color and flavor of mandarins, and therefore it is crucial to define the optimal minimum safe temperature for each mandarin variety. Furthermore, massive accumulation of terpenes is most likely the cause for the decrease in flavor acceptability of 'Odem' mandarins after storage at low chilling temperatures. (C) 2011 Elsevier B.V.

[18] SHI J X, GOLDSCHMIDT E, GOREN R, PORAT R. Molecular, biochemical and anatomical factors governing ethanol fermentation metabolism and accumulation of off-flavors in mandarins and grapefruit
Postharvest Biology and Technology, 2007,46:242-251.
DOI:10.1016/j.postharvbio.2007.05.009URL [本文引用: 1]

[19] 吴方方. 涂膜对温州蜜柑果实异味物质积累的影响
[D]. 武汉: 华中农业大学, 2010.
[本文引用: 2]

WU F F. The influence of waxing on the accumulation of off-flavor in Satsuma mandarin (Citrus unshiu Marc)
[D]. Wuhan: Huazhong Agricultural University, 2010. (in Chinese)
[本文引用: 2]

[20] 何义仲, 陈兆星, 刘润生, 方贻文, 古祖亮, 严翔, 陈红, 张洪铭, 唐焕庆, 程运江. 不同贮藏方式对赣南纽荷尔脐橙果实品质的影响
中国农业科学, 2014,47(4):736-748.
DOI:10.3864/j.issn.0578-1752.2014.04.014URL [本文引用: 1]
【Objective】The objective of this study is to optimize the storage conditions of citrus and provide a scientific foundation for storage warehouse improvement.【Method】Storage experiments were performed with commercially mature &lsquo;Newhall&rsquo; navel orange fruits using three storage methods, including mechanical cold storage (Mcs), evaporative cooling ventilating storage in mountainous region (Ecvs) and ventilating warehouse storage (Vws). Environmental parameters of these storage conditions were termly detected. Meanwhile, the fruit physiological and biochemical indexes were measured with gas chromatography and infra-red CO2 analyzer. Moreover, fruit organoleptic properties were evaluated as well. 【Result】 The environment parameters under the three storage conditions changed constantly. The temperature and relative humidity in Mcs ranged from 2.1℃ to 11.2℃ and 64.4% to 99.0%, respectively. As the weather gets warm, the temperature variations of Mcs between storehouse and transport or shelf life condition were significantly different from those of Ecvs and Vws. Although the changing trends of storage parameters in Ecvs were similar to those in Vws, industry experiences revealed that the storage condition was more suitable to orange storage in Ecvs than in Vws. The concentrations of CO2 and ethylene in Mcs were significantly higher than those in Ecvs and Vws. The contents of titratable acid, soluble solid and concentration of organic acids in fruit juice decreased with the extension of storage phase. Among these storage methods, there were significant differences in the content of titratable acid and malic acid, but not in total soluble solid in fruit juice. The content of titratable acidity after 105 days of storage (DOS) remained much higher in Ecvs than that in Mcs and Vws, and similar result was observed from the changing tendency of organic acids after 65 DOS. Prior to 135 DOS, fruit firmness, content of soluble sugar and vitamin C were higher in Mcs than those in Ecvs and Vws. The content of ethanol, acetaldehyde, methanol increased sharply at 105 DOS. At 160 DOS, the ethanol content was also significantly higher in Mcs than that in Ecvs and Vws, which aggravated fruit quality derogation and accumulated abundant off-flavor components in Mcs. During the storage, the hedonic scale of fruits in Ecvs and Vws fluctuated occasionally, the peak was observed at 35 DOS, subsequently declined gradually, and reached the lowest level at 135 DOS. Among these storage conditions, the lowest hedonic scale was detected in Mcs at 160 DOS.【Conclusion】In storage warehouse, the contents of fruit organic acids, ethanol, methanol and acetaldehyde were mainly affected by gas components, especially ethylene, and temperatures differences between storehouse and transport or shelf life conditions. And these indexes are directly related to fruit quality and organoleptic properties among these storage warehouses. Fruit quality in Mcs deteriorated at 135 DOS, while fruit in Ecvs could maintain relatively high quality until 160 DOS. Moreover, Vws is more suitable for orange short-term storage, as fruit quality degenerated gradually after 65 DOS.
HE Y Z, CHEN Z X, LIU R S, FANG Y W, GU Z L, YAN X, CHEN H, ZHANG H M, TANG H Q, CHENG Y J. Effects of different storage methods on fruit quality of ‘Newhall’ navel orange (Citrus sinensis Osbeck ‘Newhall’) in southern Jiangxi province
Scientia Agricultura Sinica, 2014,47(4):736-748. (in Chinese)
DOI:10.3864/j.issn.0578-1752.2014.04.014URL [本文引用: 1]
【Objective】The objective of this study is to optimize the storage conditions of citrus and provide a scientific foundation for storage warehouse improvement.【Method】Storage experiments were performed with commercially mature &lsquo;Newhall&rsquo; navel orange fruits using three storage methods, including mechanical cold storage (Mcs), evaporative cooling ventilating storage in mountainous region (Ecvs) and ventilating warehouse storage (Vws). Environmental parameters of these storage conditions were termly detected. Meanwhile, the fruit physiological and biochemical indexes were measured with gas chromatography and infra-red CO2 analyzer. Moreover, fruit organoleptic properties were evaluated as well. 【Result】 The environment parameters under the three storage conditions changed constantly. The temperature and relative humidity in Mcs ranged from 2.1℃ to 11.2℃ and 64.4% to 99.0%, respectively. As the weather gets warm, the temperature variations of Mcs between storehouse and transport or shelf life condition were significantly different from those of Ecvs and Vws. Although the changing trends of storage parameters in Ecvs were similar to those in Vws, industry experiences revealed that the storage condition was more suitable to orange storage in Ecvs than in Vws. The concentrations of CO2 and ethylene in Mcs were significantly higher than those in Ecvs and Vws. The contents of titratable acid, soluble solid and concentration of organic acids in fruit juice decreased with the extension of storage phase. Among these storage methods, there were significant differences in the content of titratable acid and malic acid, but not in total soluble solid in fruit juice. The content of titratable acidity after 105 days of storage (DOS) remained much higher in Ecvs than that in Mcs and Vws, and similar result was observed from the changing tendency of organic acids after 65 DOS. Prior to 135 DOS, fruit firmness, content of soluble sugar and vitamin C were higher in Mcs than those in Ecvs and Vws. The content of ethanol, acetaldehyde, methanol increased sharply at 105 DOS. At 160 DOS, the ethanol content was also significantly higher in Mcs than that in Ecvs and Vws, which aggravated fruit quality derogation and accumulated abundant off-flavor components in Mcs. During the storage, the hedonic scale of fruits in Ecvs and Vws fluctuated occasionally, the peak was observed at 35 DOS, subsequently declined gradually, and reached the lowest level at 135 DOS. Among these storage conditions, the lowest hedonic scale was detected in Mcs at 160 DOS.【Conclusion】In storage warehouse, the contents of fruit organic acids, ethanol, methanol and acetaldehyde were mainly affected by gas components, especially ethylene, and temperatures differences between storehouse and transport or shelf life conditions. And these indexes are directly related to fruit quality and organoleptic properties among these storage warehouses. Fruit quality in Mcs deteriorated at 135 DOS, while fruit in Ecvs could maintain relatively high quality until 160 DOS. Moreover, Vws is more suitable for orange short-term storage, as fruit quality degenerated gradually after 65 DOS.

[21] NAVARRO-TARAZAGA M L, DEL RIO M A, KROCHTA J M, PEREZ-GAGO M B. Fatty acid effect on hydroxypropyl methylcellulose- Beewax edible film properties and postharvest quality of coated ‘Ortanique’ mandarins
Journal of Agricultural and Food Chemistry, 2008,56:10689-10696.
DOI:10.1021/jf801967qURLPMID:18950188 [本文引用: 1]
The objective of this work was to investigate the effect of fatty acid (FA) type and content on mechanical properties, water vapor permeability and oxygen permeability of hydroxypropyl methycellulose (HPMC)-beeswax (BW) stand-alone edible films. The effect of these films formed as coatings on the postharvest quality of 'Ortanique' mandarins was also studied. Selected FAs were stearic acid (SA), palmitic acid (PA), and oleic acid (OA), using BW/FA ratios of 1:0.5 and 1:0.2 (w/w). HPMCBW coatings reduced weight and firmness loss of 'Ortanique' mandarins, without compromising flavor quality compared to uncoated mandarins. Coatings containing OA provided the best weight loss control at both concentrations tested; however, when the BW/OA ratio was 1:0.5, the coatings increased fruit internal CO2, ethanol, and acetaldehyde contents of 'Ortanique' mandarins, therefore reducing flavor compared to the rest of the coatings studied. Although barrier and mechanical properties might be used to understand coating performance, differences observed between film oxygen permeability and coating permeability indicate that permeance should be measured on the coated fruit.

[22] 方项. 柑橘商品化处理过程中蜡液浓度对果实品质的影响
[D]. 武汉: 华中农业大学, 2013.
[本文引用: 1]

FANG X. Effect of wax concentration on the fruit quality in the process of citrus fruit commercial handing
[D]. Wuhan: Huazhong Agricultural University, 2013. (in Chinese)
[本文引用: 1]

[23] HAGENMAIER R D, SHAW P E. Changes in volatile components of stored tangerines and other specialty citrus fruits with different coatings
Journal of Food Science, 2002,67:1742-1745.
DOI:10.1111/jfds.2002.67.issue-5URL [本文引用: 1]

[24] 王文生. “十二五”期间我国果蔬冷链物流面临的机遇与挑战
保鲜与加工, 2011,11(3):1-5.
[本文引用: 1]

WANG W S. Opportunities and challenges the fruit and vegetable cold-chain logistics faces during the twelfth five-year plan in China
Storage and Process, 2011,11(3):1-5. (in Chinese)
[本文引用: 1]

[25] 杨洲, 赵春娥, 马征. 果蔬预冷保鲜技术的研究//2005年中国农业工程学会学术年会论文题
2005: 112-116.
[本文引用: 1]

YANG Z, ZHAO C E, MA Z. Study on pre-cooling technique for fruit and vegetable//Thesis title of 2005 annual meeting of Chinese society of agricultural engineering
2005: 112-116. (in Chinese)
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[26] 缪小红, 周新年, 巫志龙. 生鲜食品冷链物流研究进展探讨
物流技术, 2009,28(2):24-27.
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MIAO X H, ZHOU X N, WU Z L. Research on cold chain logistics of fresh food
Logistics Technology, 2009,28(2):24-27. (in Chinese)
[本文引用: 1]