低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨貯藏品質(zhì)的影響

賈曉輝，張?chǎng)伍?，劉佰?2，馬風(fēng)麗，杜艷民，王文輝

低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨貯藏品質(zhì)的影響

賈曉輝1，張?chǎng)伍?，劉佰霖1,2，馬風(fēng)麗1，杜艷民1，王文輝1

1中國(guó)農(nóng)業(yè)科學(xué)院果樹研究所/遼寧省果品貯藏與加工重點(diǎn)實(shí)驗(yàn)室，遼寧興城 125100；2德州市農(nóng)業(yè)科學(xué)研究院，山東德州 253015

【目的】明確低O2/高CO2對(duì)玉露香梨貯藏期保綠效果及品質(zhì)維持的效果，為生產(chǎn)上延長(zhǎng)‘玉露香’梨貯藏壽命提供理論依據(jù)與技術(shù)支撐?！痉椒ā糠謩e將商業(yè)成熟的‘玉露香’梨進(jìn)行1.0 μL·L-11-甲基環(huán)丙烯（1-methylcyclopropene，1-MCP）處理，1% O2、3% CO2氣調(diào)（controlled atmosphere，CA）貯藏以及1.0 μL·L-11-MCP結(jié)合1% O2、3% CO2氣調(diào)貯藏，以普通冷藏為對(duì)照，分別于貯藏210和240 d及貨架7 d時(shí)，測(cè)定果皮顏色、葉綠素含量、果實(shí)硬度、可溶性固形物、可滴定酸、抗壞血酸等果實(shí)外觀和內(nèi)在品質(zhì)指標(biāo)，采用氣相色譜法檢測(cè)果實(shí)乙醇、乙醛含量以及乙烯釋放量和呼吸強(qiáng)度，調(diào)查并計(jì)算果柄、果心褐變指數(shù)。【結(jié)果】與普通冷藏相比，1-MCP、CA以及CA+1-MCP均可使‘玉露香’梨果實(shí)外觀保持較好的綠色，有效減輕果面油膩化程度，在冷藏240 d及240+7 d貨架時(shí)，CA+1-MCP對(duì)果皮綠色維持及油膩化控制效果更明顯。1-MCP和CA均可抑制果實(shí)硬度、可溶性固形物和可滴定酸的下降，CA可抑制果心和果柄褐變，但CA降低了果實(shí)抗壞血酸含量，CA+1-MCP減緩了CA對(duì)果實(shí)抗壞血酸的破壞作用。CA+1-MCP對(duì)乙醇和乙醛的抑制作用在貯藏240 d時(shí)效果更明顯，且20 mg·L-1的乙醇含量在‘玉露香’梨耐受閾值以下。CA+1-MCP和1-MCP對(duì)果實(shí)乙烯釋放量具有較好的抑制效果；240 d時(shí)，CA+1-MCP和CA對(duì)果實(shí)呼吸強(qiáng)度的抑制效果好于1-MCP?！窘Y(jié)論】‘玉露香’梨較耐低O2和高CO2，CA+1-MCP對(duì)‘玉露香’梨的保鮮效果體現(xiàn)在210 d以后。因此，冷藏期在210 d以內(nèi)，采用1.0 μL·L-1的1-MCP處理；而冷藏期210 d以上，則需1% O2、3% CO2的低O2/高CO2的CA結(jié)合1.0 μL·L-1的1-MCP處理，可保持果實(shí)較好的外觀和內(nèi)在品質(zhì)。

低O2/高CO2；1-MCP；‘玉露香’梨；保綠；品質(zhì)

0 引言

【研究意義】‘玉露香’梨是以庫(kù)爾勒香梨為母本、‘雪花’梨為父本雜交育成的優(yōu)質(zhì)梨新品種[1]，具備了‘庫(kù)爾勒香’梨的汁多、酥脆以及香氣濃等特點(diǎn)，深受廣大消費(fèi)者喜愛。目前，在山西、河北、寧夏、山東以及遼寧等地均有種植，產(chǎn)量呈逐年上升趨勢(shì)，也成為很多地區(qū)脫貧致富、鄉(xiāng)村振興的支柱產(chǎn)業(yè)。然而，生產(chǎn)實(shí)際中發(fā)現(xiàn)，‘玉露香’梨貯藏后期果皮退綠轉(zhuǎn)黃且油膩化現(xiàn)象突出，成為限制‘玉露香’梨高質(zhì)量發(fā)展的瓶頸問題[2]。對(duì)于綠皮梨而言，退綠轉(zhuǎn)黃是其采后成熟衰老的標(biāo)志，退綠主要是由葉綠素降解引起[3-4]。如何有效抑制果皮葉綠素降解，延緩?fù)示G轉(zhuǎn)黃對(duì)于保持果實(shí)商品性具有重要意義。【前人研究進(jìn)展】與普通冷藏相比，氣調(diào)貯藏可有效延長(zhǎng)梨果實(shí)貯藏壽命[5-7]，并已經(jīng)在西洋梨以及部分白梨品種進(jìn)行了商業(yè)化應(yīng)用。低O2和/或高CO2氣調(diào)是在氣調(diào)基礎(chǔ)上進(jìn)一步降低O2或提高CO2濃度，以達(dá)到更長(zhǎng)時(shí)間維持果實(shí)品質(zhì)的目的。目前，關(guān)于西洋梨氣調(diào)參數(shù)研究較多且較系統(tǒng)，如‘Bartlett’[8-9]、‘Packham’s Triumph’[10]、‘d’Anjou’[11-13]、‘Abate Fetel’[14]、‘Rocha’[7,15-16]以及‘Alexander Lucas’[17]，且部分品種的氣調(diào)參數(shù)在商業(yè)化貯藏中得到廣泛應(yīng)用，相對(duì)而言，我國(guó)梨品種氣調(diào)參數(shù)研究和商業(yè)化應(yīng)用還較少。已有研究發(fā)現(xiàn)，超低氧氣調(diào)雖可有效延長(zhǎng)梨果貯藏壽命，但增加了果心、果肉褐變等生理病害發(fā)生的風(fēng)險(xiǎn)[18-19]，也會(huì)降低果實(shí)可滴定酸和維生素C含量，影響果實(shí)風(fēng)味及口感[20]，高濃度的CO2則會(huì)加重果心褐變[21]。1-甲基環(huán)丙烯（1-methylcyclopropene，1-MCP），可以與乙烯競(jìng)爭(zhēng)結(jié)合受體，從而抑制乙烯介導(dǎo)的果實(shí)后熟相關(guān)生理生化反應(yīng)[22]。1-MCP可有效抑制果實(shí)硬度、可滴定酸和維生素C含量的下降[23-24]，抑制貨架期果皮退綠轉(zhuǎn)黃速度[25-26]，降低虎皮病和黑心病的發(fā)生[27-28]?！颈狙芯壳腥朦c(diǎn)】前期研究篩選出1% O2和3% CO2的氣調(diào)貯藏可有效抑制果皮葉綠素的降解，且果實(shí)未發(fā)生果心、果肉褐變現(xiàn)象，但一定程度上降低了果實(shí)可滴定酸和維生素C含量，而1-MCP處理可有效抑制‘玉露香’梨果實(shí)常溫貯藏條件下可滴定酸和維生素C含量的下降，也起到了較好的保綠效果。基于以上原因，本研究擬通過果實(shí)采收后先采用1-MCP熏蒸處理，而后進(jìn)行氣調(diào)冷藏?！緮M解決的關(guān)鍵問題】探索顯著延長(zhǎng)‘玉露香’梨果實(shí)冷藏期限，既能保持貯藏后期果皮綠色維持，又能抑制果實(shí)內(nèi)在品質(zhì)的下降。

1 材料與方法

1.1 材料及處理

本研究在2016—2017年‘玉露香’梨氣調(diào)參數(shù)篩選試驗(yàn)基礎(chǔ)上開展，從設(shè)定的O2分別為1%、3%和5%以及CO2分別為3%和5%的氣調(diào)參數(shù)中，篩選出‘玉露香’梨最佳氣調(diào)參數(shù)為1% O2和3% CO2。在此基礎(chǔ)上，2018年9月8日，‘玉露香’梨（Yuluxiang）果實(shí)從山西省臨汾市隰縣午城鎮(zhèn)寺坡村采收。果園管理水平中上等，選取10株有代表性的樹體，樹齡15年。果實(shí)采收72 h后運(yùn)至中國(guó)農(nóng)業(yè)科學(xué)院果樹研究所（遼寧興城）實(shí)驗(yàn)室，挑選大小均勻、成熟度相對(duì)一致、無病蟲害及機(jī)械傷的健康果實(shí)，其中20個(gè)用于果實(shí)基礎(chǔ)指標(biāo)測(cè)定（表1）。其余果實(shí)作如下處理：

對(duì)照組（CK）：從挑選出的梨果中取出200個(gè)，15℃環(huán)境條件下，在塑料帳內(nèi)密封處理14 h，而后分裝入3個(gè)氣調(diào)瓶?jī)?nèi)，置于（0±0.3）℃下冷藏預(yù)冷3 d后，封蓋內(nèi)通空氣。

1-MCP組：從挑選出的梨果中取出200個(gè)，在15℃環(huán)境條件下，用1.0 μL·L-11-MCP在塑料帳密封處理14 h，而后分裝入3個(gè)氣調(diào)瓶?jī)?nèi)，置于（0±0.3）℃下冷藏預(yù)冷3 d后，封蓋內(nèi)通空氣。

CA組：從挑選出的梨果中取出200個(gè)，分裝處理同對(duì)照組，而后氣調(diào)瓶連續(xù)通1% O2和3% CO2。

CA+1-MCP組：從挑選出的果子中取出200個(gè)，分裝處理同1-MCP組，而后氣調(diào)瓶連續(xù)通1% O2和3% CO2。

每7 d采用瑞士產(chǎn)Checkmate氣體檢測(cè)儀監(jiān)測(cè)氣瓶?jī)?nèi)氣體成分是否穩(wěn)定，采用排水法檢查尾氣是否堵塞等。分別于冷藏210和240 d時(shí)取出果實(shí)，進(jìn)行相關(guān)指標(biāo)的觀察與測(cè)定，每次每個(gè)處理每個(gè)重復(fù)隨機(jī)取出30個(gè)果實(shí)，其中每個(gè)重復(fù)中10個(gè)果實(shí)用于基礎(chǔ)值測(cè)定，9個(gè)果實(shí)用于呼吸強(qiáng)度和乙烯釋放量測(cè)定，10個(gè)果實(shí)用于7 d貨架期測(cè)定。

表1 試驗(yàn)用‘玉露香’梨果實(shí)基礎(chǔ)值

1.2 測(cè)定方法

1.2.1 果皮顏色測(cè)定 果皮顏色使用CR-400色差儀測(cè)定，所用光源為D65光源。具體測(cè)定方法見文獻(xiàn)[29]。

1.2.2 果實(shí)內(nèi)在品質(zhì)指標(biāo)測(cè)定 果實(shí)硬度用GS-15水果質(zhì)地分析儀測(cè)定，探頭直徑11.3 mm；可溶性固形物（total soluble solid，TSS）含量用PR-101α折糖儀測(cè)定；抗壞血酸（ascorbic acid，ASA）和可滴定酸（titritable acidity，TA）含量使用瑞士萬通808智能電位滴定儀測(cè)定，具體測(cè)定方法見文獻(xiàn)[29]。

1.2.3 果皮葉綠素的提取和含量測(cè)定 采用紫外分光光度計(jì)法，具體參考文獻(xiàn)[30]的方法。

1.2.4 乙醇和乙醛含量 采用GC-2010氣相色譜儀頂空進(jìn)樣法測(cè)定，分別將果肉（包括果皮）和果心勻漿后過濾，取上清液5 mL，在頂空瓶?jī)?nèi)先后加入1.335—1.350 g NaCl、蒸餾水 1 mL 和上清液5 mL。測(cè)定方法參見曹建康等[31]。

1.2.5 果柄褐變指數(shù)、果心褐變指數(shù) 果柄保鮮指數(shù)以果柄干枯長(zhǎng)度占果柄總長(zhǎng)度的比例計(jì)算。共分6級(jí)，其中，0級(jí)：果柄未干枯；Ⅰ級(jí)：果柄干枯長(zhǎng)度＜1/3；Ⅱ級(jí)：果柄干枯長(zhǎng)度1/3—1/2；Ⅲ級(jí)：果柄干枯長(zhǎng)度1/2—2/3；Ⅳ級(jí)：果柄干枯長(zhǎng)度＞2/3；Ⅴ級(jí)果柄全部干枯。果心褐變指數(shù)以果心褐變面積占果心總面積的比例計(jì)算，共分6級(jí)，其中，0級(jí)：果心無褐變現(xiàn)象，顏色正常；Ⅰ級(jí)：果心褐變面積＜1/3，即褐變現(xiàn)象較輕微但肉眼能見；Ⅱ級(jí)：果心褐變面積1/3—1/2；Ⅲ級(jí)：果心褐變面積1/2—2/3；Ⅳ級(jí)：果心褐變面積＞2/3；Ⅴ級(jí)：果心全部褐變。分別根據(jù)布朗指數(shù)公式進(jìn)行計(jì)算：

果柄褐變指數(shù)=×100；

果心褐變指數(shù)=×100。

1.2.6 呼吸速率和乙烯釋放速率測(cè)定 采用SP-7890氣相色譜儀（山東魯南公司）同時(shí)進(jìn)行測(cè)定，每天測(cè)定1次，連續(xù)測(cè)定8 d，呼吸強(qiáng)度和乙烯釋放量單位分別為mg CO2·kg-1·h-1和μL·kg-1·h-1。具體測(cè)定方法參見參考文獻(xiàn)[26]。

1.3 數(shù)據(jù)分析

利用SPSS 22.0軟件進(jìn)行數(shù)據(jù)統(tǒng)計(jì)分析，使用Duncan新復(fù)極差法進(jìn)行不同處理間差異顯著性分析。

2 結(jié)果

2.1 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨果皮顏色的影響

L值可較好地反映果皮油膩化程度，其中，L值越高，油膩化程度越高；H值可較好地反映果皮由綠轉(zhuǎn)黃情況，其中，H值越低，果皮越黃。由圖1可知，隨著貯藏時(shí)間的延長(zhǎng)，L值逐漸升高，H值逐漸降低。貯藏210 d及210 d+7 d貨架時(shí)，1-MCP與CA之間L值差異不顯著，而在240 d時(shí)，CA果實(shí)L值均顯著低于1-MCP；無論210 d還是240 d，單一的CA或1-MCP處理對(duì)H值的影響差異不顯著?？傮w上看，CA、1-MCP以及CA+1-MCP均抑制了果皮L值升高和H值下降，且CA+1-MCP的果皮L值顯著低于其他處理，而H值則顯著高于其他處理。由此可見，與1-MCP相比，CA可有效抑制冷藏至240 d及后期‘玉露香’梨果皮的油膩化，其中，CA+1-MCP處理的抑制效果明顯優(yōu)于單一的CA或1-MCP處理。肉眼觀察發(fā)現(xiàn)，與CK相比，不同處理均可使‘玉露香’梨果實(shí)外觀保持較好的綠色，有效減輕果面油膩化程度，尤其在冷藏240 d及240+7 d貨架時(shí)，CA+1-MCP對(duì)果皮綠色維持及油膩化控制效果更明顯（圖2），這與果皮顏色測(cè)定結(jié)果相吻合。

不同小寫字母表示相同貯藏時(shí)間不同處理間差異顯著，*代表貨架時(shí)間。下同

A: CK; B: 1-MCP; C: CA; D: CA+1-MCP

2.2 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨果皮葉綠素含量的影響

由圖3可知，隨著貯藏期的延長(zhǎng)，‘玉露香’梨果皮葉綠素含量呈逐漸下降趨勢(shì)。貯藏210 d及210+ 7 d時(shí)，1-MCP組果皮葉綠素a、b及葉綠素a+b含量顯著高于CK和CA處理，而貯藏至240 d及貨架7 d時(shí)，CA以及CA+1-MCP組果皮葉綠素含量顯著高于CK和1-MCP組（＜0.05）。進(jìn)一步說明，與1-MCP組相比，CA及CA+1-MCP組可有效抑制‘玉露香’梨貯藏240 d及以后的葉綠素下降，且CA+1-MCP組效果最好。

圖3 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨果皮葉綠素含量的影響

2.3 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨果柄、果心褐變的影響

貯藏210、210+7 d貨架以及240 d時(shí)，CA以及CA+1-MCP均未出現(xiàn)果柄褐變現(xiàn)象，240+7 d貨架時(shí)，果柄出現(xiàn)輕微褐變，但顯著低于CK和1-MCP處理；210 d時(shí)，CK果心褐變指數(shù)顯著高于其他3個(gè)處理，但3個(gè)處理間差異不顯著，而210+7 d、240 d以及240+7 d時(shí)，不同處理間果心褐變指數(shù)差異顯著，其中，CA+1-MCP果心褐變指數(shù)最低，其次為CA（圖4）。因此，CA+1-MCP對(duì)果柄、果心褐變的抑制效果最好。

圖4 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨果柄和果心褐變指數(shù)的影響

2.4 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨內(nèi)在品質(zhì)的影響

由表2可以看出，整個(gè)冷藏期及貨架7 d時(shí)，與CK相比，1-MCP、CA以及CA+1-MCP均可顯著抑制果實(shí)硬度的下降（＜0.05），但不同處理間差異不顯著。210 d及210+7 d貨架時(shí)，不同處理間可溶性固形物含量差異不顯著，而在240 d及240+7 d時(shí)，1-MCP、CA以及CA+1-MCP均可顯著抑制可溶性固形物的下降（＜0.05），且以CA+1-MCP抑制效果最好，其次為CA。整個(gè)冷藏期及貨架7 d時(shí)，與CK相比，1-MCP、CA以及CA+1-MCP均可顯著抑制果實(shí)可滴定酸含量的下降（＜0.05），且以CA+1-MCP抑制效果最好，其次為CA。210 d和240 d時(shí)，與CK相比，1-MCP以及CA+1-MCP均可抑制抗壞血酸含量的下降，而單一CA則促進(jìn)了抗壞血酸含量的下降；210+7 d和240+7 d時(shí)，與CK相比，1-MCP抑制了抗壞血酸含量的下降，CA以及CA+1-MCP均顯著促進(jìn)了抗壞血酸含量的下降（＜0.05），但CA+1-MCP減弱了單一CA對(duì)抗壞血酸的破壞作用。由表2也可看出，所有處理果實(shí)貨架7 d時(shí)可滴定酸和抗壞血酸含量均高于剛從冷庫(kù)取出時(shí)。

表2 氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨內(nèi)在品質(zhì)的影響

表中數(shù)據(jù)為平均值±標(biāo)準(zhǔn)偏差，同一行相同指標(biāo)間不同小寫字母表示經(jīng)Ducan’s差異顯著性分析達(dá)顯著水平（＜0.05）

Data are means ± std. Values followed by different small letters within the same line are significantly different according to Duncan’s multiple range test at＜0.05

2.5 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨乙醇和乙醛含量的影響

由圖5可知，冷藏210 d和240 d時(shí)，CK和1-MCP處理果實(shí)均未檢測(cè)到乙醇，而CA和CA+1-MCP果實(shí)均檢測(cè)到乙醇，濃度在20 mg·L-1上下波動(dòng)；210+7 d時(shí)，僅CK檢測(cè)到乙醇，其他3個(gè)處理均未檢測(cè)到乙醇含量；240+7 d時(shí)，均檢測(cè)到乙醇，且乙醇含量由高到低依次為CK＞1-MCP＞CA＞CA+1-MCP，且不同處理間差異顯著。210和240 d時(shí)，1-MCP可顯著抑制果實(shí)乙醛含量，CA和CA+1-MCP的乙醛含量高于CK，210+7 d和240+7 d時(shí)，CA和CA+1-MCP對(duì)乙醛的抑制效果均好于1-MCP。由此可見，CA+1-MCP對(duì)乙醇和乙醛的抑制作用在貯藏240 d時(shí)效果更明顯，且20 mg·L-1的乙醇含量在‘玉露香’梨耐受閾值以下。

圖5 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨乙醇和乙醛含量的影響

2.6 低O2/高CO2氣調(diào)結(jié)合1-MCP對(duì)‘玉露香’梨呼吸強(qiáng)度和乙烯釋放量的影響

由圖6可知，‘玉露香’梨屬于典型的呼吸躍變型果實(shí)。冷藏210 d時(shí)，1-MCP處理的‘玉露香’梨果實(shí)貨架期呼吸強(qiáng)度最低，CK最高，CA和CA+ 1-MCP介于二者之間；而乙烯釋放量則以CA+1-MCP最低，其次為1-MCP處理，對(duì)照在貨架4 d及以前最高，貨架4 d后則以CA果實(shí)最高。冷藏240 d時(shí)，CA+1-MCP果實(shí)呼吸強(qiáng)度最低，其次為CA，CK最高，而乙烯釋放量則以CA+1-MCP最低，其次為1-MCP處理，而CK最高。由此可見，CA+1-MCP和1-MCP始終對(duì)乙烯釋放量具有較好的抑制效果，而冷藏210 d貨架期，1-MCP對(duì)呼吸強(qiáng)度抑制效果最明顯，冷藏240 d貨架期，CA+1-MCP和CA對(duì)呼吸強(qiáng)度的抑制效果好于1-MCP。

A和C為冷藏210 d取出，B和D為冷藏240 d取出 A and C indicate 210 days of cold storage, B and D indicate 240 days of cold storage

3 討論

3.1 ‘玉露香’梨對(duì)低O2和/或高CO2的耐受能力

根據(jù)不同梨品種在氣調(diào)環(huán)境下對(duì)低O2或高CO2的耐受能力，將其分為敏感、中等耐受和耐受3個(gè)等級(jí)[32]?！瓵lexander Lucas’‘Conference’以及‘鴨梨’均表現(xiàn)出對(duì)低O2和高CO2的極度敏感性[17,33-35]?！瓸artlet’和‘Bosc’為對(duì)低O2或高CO2中等耐受梨品種[36-37]。而‘d’Anjou’‘庫(kù)爾勒香’梨屬于對(duì)低O2或高CO2耐受的品種[13,30]。氣調(diào)貯藏條件下，果皮、果肉以及果心褐變等生理病害的發(fā)生是檢驗(yàn)果實(shí)對(duì)低O2或高CO2耐受能力的重要指標(biāo)。本研究發(fā)現(xiàn)，‘玉露香’梨在1% O2+3% CO2的氣調(diào)環(huán)境下果心和果柄褐變指數(shù)顯著低于CK，且未發(fā)生果皮和果肉褐變。乙醇和乙醛含量是果實(shí)衰老的預(yù)警指標(biāo)，也是商業(yè)化氣調(diào)監(jiān)測(cè)的重要指標(biāo)[38]。研究發(fā)現(xiàn)，無論冷藏210 d還是240 d，1% O2+3% CO2的氣調(diào)果實(shí)剛?cè)〕鰰r(shí)均檢測(cè)到較高濃度的乙醇和乙醛含量，但在貨架7 d時(shí)，乙醇和乙醛含量顯著低于不經(jīng)氣調(diào)處理的果實(shí)，由此可見，1% O2+3% CO2產(chǎn)生的乙醇和乙醛濃度在果實(shí)耐受范圍內(nèi)。因此，綜合認(rèn)為，‘玉露香’梨屬于對(duì)低O2和/或高CO2耐受的梨品種。

3.2 低O2/高CO2氣調(diào)結(jié)合1-MCP影響‘玉露香’梨果實(shí)保綠和褐變

3.3 低O2/高CO2氣調(diào)結(jié)合1-MCP影響‘玉露香’梨果實(shí)品質(zhì)

‘玉露香’梨屬酥脆型梨果品種，果實(shí)硬度直接影響其口感。感官評(píng)價(jià)發(fā)現(xiàn)，隨著貯藏時(shí)間延長(zhǎng)和果實(shí)的衰老，果肉由酥脆轉(zhuǎn)松軟，且貨架7 d時(shí)尤其明顯。因此，硬度是評(píng)價(jià)‘玉露香’梨保鮮效果的另一個(gè)主要評(píng)價(jià)指標(biāo)。本研究結(jié)果表明，CA、1-MCP以及CA結(jié)合1-MCP均抑制了整個(gè)冷藏及貨架期果實(shí)硬度的下降，且以CA+1-MCP對(duì)硬度的維持效果最佳。可溶性固形物和可滴定酸可反映果實(shí)的風(fēng)味，在整個(gè)貯藏期不同處理對(duì)可溶性固形物和可滴定酸含量的作用效果與硬度一致。研究發(fā)現(xiàn)，CA顯著促進(jìn)了‘玉露香’梨ASA含量的下降，1-MCP顯著抑制了ASA含量的下降，而CA+1-MCP減弱了CA對(duì)果實(shí)ASA的破壞水平。這與前人通過低O2對(duì)‘Conference’梨處理結(jié)果一致。已有研究發(fā)現(xiàn)，ASA低于一定閾值時(shí)，其值與果實(shí)褐變具有一定相關(guān)性[46]，但本研究中CA并未增加果實(shí)的褐變程度，初步推測(cè)可能與1% O2和3% CO2并未破壞ASA至閾值以下有關(guān)。另外，‘玉露香’梨貨架期ASA含量均高于出庫(kù)時(shí)，這與前期在不同溫度貯藏的‘玉露香’梨和不同包裝袋貯藏的‘庫(kù)爾勒香’梨上的研究結(jié)果相似。

4 結(jié)論

‘玉露香’梨為呼吸躍變型梨果品種，較耐低O2和高CO2。1-MCP（1.0 μL·L-1）和CA（1% O2、3% CO2）均可抑制果皮退綠轉(zhuǎn)黃和油膩化，抑制果實(shí)硬度、可溶性固形物和可滴定酸的下降，CA可抑制果心和果柄褐變，冷藏240 d時(shí)CA的保綠效果更明顯，但CA降低了果實(shí)ASA含量，1-MCP則可顯著抑制果實(shí)ASA含量下降。因此，冷藏期在210 d以內(nèi)，可采用單一1.0 μL?L-1的1-MCP處理；而冷藏期210 d以上，則需1.0 μL?L-1的1-MCP處理后，再采用1% O2、3% CO2的低O2/高CO2的CA貯藏，可保持果實(shí)較好的外觀和內(nèi)在品質(zhì)，冷藏壽命顯著延長(zhǎng)。

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Effects of Low Oxygen/High Carbon Dioxide Controlled Atmosphere Combined with 1-Methylcyclopropene on Quality of Yuluxiang Pear During Cold Storage

JIA XiaoHui1, ZHANG XinNan1, LIU BaiLin1, 2, MA FengLi1, DU YanMin1, WANG WenHui1

1Research Institute of Pomology, Chinese Academy of Agricultural Sciences/Liaoning Key Laboratory of Fruit Storage and Processing, Xingcheng 125100, Liaoning;2Dezhou Academy of Agricultural Sciences, Dezhou 253015, Shandong

【Objective】The objective of this study was to clarify the effects of a controlled atmosphere (CA) with low oxygen (O2)/high carbon dioxide (CO2) on chlorophyll maintenance and quality of Yuluxiang pears during cold storage, so as to provide a theoretical basis and technical support for prolonging the storage life of Yuluxiang pear.【Method】 The storage experiments were performed with commercial mature Yuluxiang pears treated with 1.0 μL·L-11-Methylcyclopropene (1-MCP), 1% O2, 3% CO2, and 1.0 μL·L-11-MCP combined with 1% O2and 3% CO2, with air treatment as the control. The peel color, chlorophyll content, firmness, total soluble solids, titratable acid, ascorbic acid, and other quality indices were measured at 210 and 240 days of storage and 7 days of shelf life, respectively. Ethanol and acetaldehyde content, ethylene production, and respiratory rate of the fruits were detected by gas chromatography, and the browning indices of the fruit stalk and core were investigated and calculated.【Result】 Compared with ordinary cold storage, 1-MCP, CA, and CA+1-MCP could better maintain the green color of Yuluxiang pear fruits and effectively reduce the degree of greasiness on the fruit surface. CA+1-MCP had a more pronounced effect on the green color maintenance and greasiness control of the peel when they were refrigerated for 240 days and 240+7 days. 1-MCP and CA could inhibit the decline in fruit firmness, total soluble solids, and titratable acid. CA could inhibit browning of the core and stalk, but CA used alone reduced the content of ascorbic acid in the fruits, and CA+1-MCP slowed the decline of ascorbic acid in CA fruits. The inhibitory effect of CA+1-MCP on ethanol and acetaldehyde was more apparent when stored for 240 days, and the ethanol content of 20 mg·L-1was below the tolerance threshold of Yuluxiang pears. CA+1-MCP and 1-MCP had strong inhibitory effects on ethylene production across the entire storage period. At 240 days, CA+1-MCP and CA had a stronger inhibitory effect on the respiratory rate than 1-MCP.【Conclusion】 Yuluxiang pears were respiratory climacteric pears, resistant to low O2and high CO2. The freshness maintenance effect of CA+1-MCP on Yuluxiang pear was maintained after 210 days. Therefore, when the cold storage period was less than 210 days, a single 1-MCP treatment of 1.0 μL·L-1could be used. When the cold storage period was greater than 210 days, the fruit should be first treated with 1.0 μL·L-11-MCP, and then stored under CA with low O2/high CO2of 1% O2and 3% CO2, which could maintain the appearance and internal quality of fruits, as well as significantly prolong the cold storage life.

low O2/high CO2; 1-MCP; Yuluxiang pear; chlorophyll maintenance; quality

10.3864/j.issn.0578-1752.2022.23.012

2022-04-18；

2022-08-03

國(guó)家現(xiàn)代農(nóng)業(yè)產(chǎn)業(yè)技術(shù)體系建設(shè)專項(xiàng)（CARS-28-22）、中國(guó)農(nóng)業(yè)科學(xué)院科技創(chuàng)新工程（CAAS-ASTIP）、國(guó)家重點(diǎn)研發(fā)計(jì)劃（2016YFD0400903-06）

賈曉輝，E-mail：jiaxiaohui@caas.cn。通信作者王文輝，E-mail：wangwenhui@caas.cn

（責(zé)任編輯 趙伶俐）