Controlled atmosphere (CA) storage is a primary commercial method used worldwide to prevent superficial scald. However, the key molecular mechanisms underlying its protective effect remain unclear. In this study, CA treatment effectively inhibited superficial scald development during 210 d of cold storage. This effect was accompanied by reduced biosynthesis and accumulation of ethylene, alpha-farnesene, conjugated trienol 281 (CTol281), hydrogen peroxide (H2O2), and superoxide anion (O2 & sdot;-), as well as mitigation of cell plasmolysis and apoptosis. Through analysis and experimental validation of transcriptomic profiles, gene expression patterns, and transcriptional regulation, we identified PbDREB1A, which acted as a positive regulator of cold acclimation in plants, exhibited a significantly upregulation under low oxygen CA. Further investigation revealed that PbDREB1A and the potential ethylene suppressor PbERF4 showed a continuous upward trend during the initial 120 d of CA storage, with expression levels significantly higher than those observed under air control conditions. Subcellular localization and bimolecular fluorescence complementation assays confirmed that PbDREB1A interacts with PbERF4 in the nucleus. Dual-luciferase assay revealed that PbDREB1A activated PbERF4 expression by targeting its promoter, whereas PbERF4 suppressed PbACO1 expression. Moreover, the genes related to coldresponsive sugars and protein metabolism including a-amylase, sugar transporter ERD6-like, sugar transporter protein 13, proline dehydrogenase 2, and glutathione S-transferase were significantly upregulated in CA-treated fruits. In conclusion, we identified a novel hypoxia-enhanced transcription factor, PbDREB1A, which directly activates PbERF4 to suppress PbACO1 expression and reduce ethylene biosynthesis. The PbDREB1A-PbERF4 module may play an important role in the molecular mechanisms through which low-oxygen CA treatment inhibits superficial scald.

This study analyzed the volatile profiles of 16 cold-region small-fruited apple cultivars using HS-SPME-GC–MS and multivariate statistics. A total of 140 VOCs were identified, with esters being the most abundant. Multivariate analysis revealed 34 key differential compounds, including ethyl butyrate and (E)-2-hexenal. Cultivars with superior sensory scores, such as A-8 (‘Niunaiguo’) and A-15 (‘Saiwaihong’), were characterized by high levels of characteristic esters (ethyl 2-methylbutyrate) and α-farnesene, contributing to their fruity and sweet notes. Intense fruity aromas in A-1 (‘Lingdangguo’) and A-7 (‘K9’) were linked to high concentrations of ethyl butyrate and ethyl hexanoate. This research provides a theoretical foundation for the quality evaluation and genetic breeding of distinctive cold-region apple cultivars.

This study systematically investigated the physicochemical properties and aroma dynamics of highbush blueberry (Vaccinium corymbosum "Legacy") across five maturity stages (I: green to V: dark blue) using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The fruit diameter, fresh fruit weight, soluble solids content, soluble sugars, and vitamin C content of these blueberries were found to increase significantly with maturation, whereas the firmness and titratable acidity decreased. Seventy-seven volatile organic compounds (VOCs), predominantly consisting of aldehydes (59.09%-85.18%) and alcohols, were identified. The diversity of VOCs decreased from 65 in Maturity Stage I to 38 in Maturity Stage V, although aldehydes such as (E)-2-hexenal (which peaked at 1292.81 μg/kg in Maturity Stage I) remained consistently present across the maturation stages. Orthogonal partial least squares discrimination analysis identified 10 differential volatile metabolites, including (E)-2-hexenal and hexanal, that distinguished between maturity stages. Odor activity values revealed 17 key aroma contributors, notably hexanal (floral), β-myrcene (peppery), and (E)-2-hexenal (green). Fruits at Maturity Stage IV exhibited the most intense aroma and optimal quality, characterized by their light blue peel, high soluble solids content (14.66%), balanced acidity (0.615%), and rich fruity notes. These findings establish distinct volatile signatures for each maturity stage and serve as objective biochemical markers to optimize harvest timing in blueberry cultivation. Furthermore, these stage-specific profiles provide a scientific basis for raw material grading in product processing, guiding the targeted selection of fruits for fresh market distribution or specific processed products such as juices and fermented wines.

During storage, melatonin (MT) suppressed ethylene production in apple fruit. However, the underlying mechanism is rarely reported. Exogenous MT treatment was found to inhibit ethylene production and postpone apple fruit ripening. In the ripening process, MT treatment downregulated the expression of MdACS1 and MdACO1, the key genes of ethylene synthesis. Moreover, MT treatment markedly suppressed the expression of MdERF1 and MdERF3 within the ethylene signal transduction pathway. Subsequent research demonstrated that MdERF1 interacts with the MdERF3 promoter, upregulating its expression and consequently stimulating MdACS1 transcription. MdERF1 also interacts with MdERF3 to enhance the regulation of both MdERF3 and MdACS1. In addition, MdREM10 acts upstream of MdERF1 by directly binding to the promoter of MdERF1 and promoting its transcription. Collectively, MT suppresses ethylene production and fruit ripening by targeting MdERF1 and MdERF3. As a target gene of MdREM10, MdERF1 indirectly promotes MdACS1 transcription through two pathways: direct upregulation of MdERF3 and interaction with MdERF3. Our study elucidates the molecular mechanism through which MT suppresses ethylene biosynthesis by inhibiting ethylene response factors, offering new insights into the interaction between MT and ethylene in fruit ripening.

Ascorbate (AsA) redox status participated in the scald development of Pyrus bretschneideri Rehd. fruit as a cellular redox sensor. By a conjoint analysis of metabolites, enzyme activities and gene expression profiles in AsA-GSH cycle of the chilled pear, PbrDHAR5 was characterized as the candidate gene involved in this process. PbrDHAR5, located in cytosol and nucleus, catalyzed DHA reduction into AsA in vitro and in vivo, elevating AsA redox status and thus fruit chilling tolerance; moreover, the catalytic Cys20 residue in PbrDHAR5 played critical role in this reaction. After analyzing the expression profiles of the differentially expressed TFs, PbrWRKY83 demonstrated higher correlation with PbrDHAR5 than others. PbrWRKY83, located in nucleus, could interact with the only two W-box elements in PbrDHAR5 promoter as monomer and then activate its expression, leading to the improvement of AsA redox status and thus fruit chilling tolerance. In a further study, we explored that the H2O2-mediated S-sulfenylation of Cys20 residue in PbrDHAR5 accumulated upon scald development, suppressed its activity, and thus caused the decrement of AsA redox status. Taken together, our results implied that the H2O2-mediated S-sulfenylation of PbrDHAR5 attenuates the role of PbrWRKY83-PbrDHAR5 module, which positively regulates AsA redox status during scald development in pear.

[Objective]Akizuki pear(Pyrus pyrifolia Nakai),a late-maturing sand pear cultivar,is prized for its superior organoleptic quality and extended harvest window.However,this variety exhibits significant postharvest challenges,particularly rapid flesh softening and skin cracking during storage,which substantially diminishes its marketability and commercial value.In previous studies,we have demonstrated that these physiological changes are closely associated with increased ethylene produc-tion and respiratory activity during fruit ripening.Consequently,developing an efficient,low-cost,and user-friendly postharvest preservation technique to mitigate quality deterioration in Akizuki pears is of paramount importance for the fruit industry.Ripening represents the terminal phase of fruit maturation,characterized by a climacteric rise in respiration and a concomitant surge in ethylene biosynthesis.These metabolic shifts accelerate the ripening process,leading to reduced shelf life and economic loss-es.The application of 1-methylcyclopropene(1-MCP),a potent ethylene action inhibitor,has proven ef-fective in extending the storage potential of Akizuki pears,enabling long-distance transportation and prolonged marketability.Similarly,chitosan-based edible coatings have emerged as a promising alterna-tive to modified atmosphere packaging(MAP),as they modulate fruit respiration and delay senescence.Despite these advancements,the underlying mechanisms of flesh softening in Akizuki pears under ambi-ent storage conditions(20±1)℃ remain insufficiently explored.In this study,the synergistic effects of hypertonic CO2 preservation bags in conjunction with 1-MCP and chitosan treatments were investigated on postharvest fruit quality maintenance.By systematically analyzing the changes in fruit texture,soft-ening-related enzyme activities,and oxidative stress markers,this research aimed to elucidate the bio-chemical basis of fruit softening and establish an optimized protocol for ambient-conditions(20±1)℃storage and transportation of Akizuki pears.[Methods]Four treatments were established under ambient logistics conditions at(20±1)℃:The control group(CK),treatment with a hypertonic CO2 film bag,treatment with a hypertonic CO2 film bag(MAP)combined with a 1-MCP slow-release agent(MAP+1-MCP),and treatment with a hypertonic CO2 film bag combined with chitosan(MAP+chitosan).After sealing the three types of MAP treatment packaging bags for 3 days(72 hours),the bags were opened to remove 1-MCP slow-release agent,and then the pears were stored under shelf conditions until 19 days(sealing for 3 days and open for 16 days)with open packaging.During storage,the following indexes were measured,such as quality of Akizuki pear,texture profile analysis(TPA)of the flesh including co-hesiveness,springiness,gumminess,and chewiness,respiration rate,ethylene production rate,starch content and amylase activity(AMS),and the relevant softening and senescence-related indices.[Re-sults]Compared with CK,both the treatment with single hypertonic CO2 film bags and the treatment combining hypertonic CO2 film bags with 1-MCP slow-release agent can delay the decline of firmness,cohesiveness,elasticity,adhesiveness,and chewiness of Akizuki pears after harvest,and inhibit enzyme activity,the respiration rate and ethylene release of the fruits.The results showed after 15 days of stor-age,the hardness of the hypertonic CO2 film bags treatment and the hypertonic CO2 film bags with 1-MCP slow-release agent treatment decreased to 4.06 kg·cm-2 and 5.00 kg·cm-2,respectively,and the stem freshness indices were 21 and 73,respectively,and delay the increase in the activity of AMS,CL,and pectin PME,inhibiting the increase of MDA within the fruits.The peak of respiration was delayed for 4 days and 6 days and the peak values increased by 18.2％and 15.9％respectively.The hypertonic CO2 film bags with 1-MCP slow-release agent treatment delayed ethylene rate for 2 days and the peak values increased by 30.4％.However,as the storage time extended,the softening of the fruits treated with single hypertonic CO2 film bags became manifest,while the treatment combining hypertonic CO2 film bags with 1-MCP slow-release agent can still maintain the good fruit quality until the end of the storage period.After 19 days of storage the treatment combining hypertonic CO2 film bags with 1-MCP slow-release agent can hold cohesion cohesiveness of 0.26,springiness of 1.79 mm,gumminess of 16.72 N,chewiness of 24.3 mJ,4.49 kg·cm-2 of hardness,and a stem freshness of 46.67.The treatment with hypertonic CO2 film bags combined with chitosan accelerated the softening process of the fruits during storage.The peak of respiration brought forward 4 days compared with the combining hyperton-ic CO2 film bags with 1-MCP slow-release agent treatment and the peak values increased by 38.6％.The ethylene release rate increased to 358.75 nL·kg-1·h-1.The treatment with hypertonic CO2 film bags combined with chitosan also promoted enzyme activity of the fruits.[Conclusion]Both the hypertonic CO2 film bags treatment and the hypertonic CO2 film bags combined with 1-MCP treatment can delay the softening of Akizuki pears and maintain good fruit quality during room-temperature storage.Howev-er,the hypertonic CO2 film bags combined with 1-MCP slow-release agent treatment exhibits a better storage effect.The treatment of Akizuki pears with hypertonic CO2 film bags combined with chitosan coating not only increases production costs but also fails to achieve satisfactory preservation efficacy,and is therefore not recommended for commercial application.

Athelia bombacina (A. bombacina) is a newly discovered and important post-harvest fruit pathogen. We previously found that it exhibited a strong ability to produce laccase, an important pathogenic factor of various pathogens and a major enzyme that destroys the host's first line of defense. However, it remains unclear whether the Lac genes, which are significantly up-regulated during the interaction between A. bombacina and its host, play a role in regulating the growth, development and pathogenicity of A. bombacina. In this study, the key core gene AbLac4 in the Lac genes family was identified and characterized through bioinformatics analysis based on transcriptome data. The absence of AbLac4 inhibited colony growth, reduced biomass, slowed down apical growth, and caused "U"-shaped structures in A. bombacina. In addition, the absence of AbLac4 down-regulated the expression of the key genes related to sporulation (abaA-1, abaA-2 and abaA-3), reduced sporulation, with no effect on spore germination rate. The ΔAbLac4 was more sensitive to cell wall stress and temperatural stress. The absence of AbLac4 also reduced the pathogenicity of A. bombacina in 'Huangguan' pears. Furthermore, the absence of AbLac4 significantly reduced Lac activity in the early culture environment and disrupted the pH balance. Additionally, the contents of oxalic acid and soluble sugar were significantly reduced, and the activities of hemicellulase and pectinase were decreased significantly on the 5th day of culture. Extracellular enzyme-related genes (EpgA, EpgB, PG, EngA, EngB, ExgA and ExgB) in A. bombacina were also down-regulated. In summary, AbLac4 exhibited a positive correlation with the growth, development, and pathogenic capability of A. bombacina.

Sweet cherry (Prunus avium L.) is becoming increasingly popular in China, but its postharvest quality deteriorates significantly during harvest storage and transport. Here, we investigated the efficiency of different modified atmosphere packaging (MAP) treatments on the quality and physiology of ‘Meizao’ sweet cherry during 60 days of cold storage (0 ± 0.5 °C). Fruits were sealed in four types of MAP low-density polyethylene (LDPE) liners (PE20, PE30, PE40, and PE50), with unsealed 20 μm LDPE packaging bags used as the control. Our findings demonstrated that PE30 packaging established an optimal gas composition (7.0~7.7% O2 and 3.6~3.9% CO2) that effectively preserved ‘Meizao’ sweet cherry quality. It maintained the fruit color, firmness, soluble solid content (SSC), titratable acidity (TA), and vitamin C (Vc) content while simultaneously delaying deteriorative processes such as weight loss, pedicel browning, and fruit decay. These results indicate that PE30 was the most suitable treatment for preserving the quality of ‘Meizao’ sweet cherries during cold storage. Furthermore, physiological research showed that significant inhibition of respiration rate was achieved by PE30, accompanied by maintained activities of antioxidant enzymes (CAT, POD, and SOD), which consequently led to reduced accumulations of ethanol and malondialdehyde (MDA) during cold storage. To date, no systematic studies have investigated the physiological and biochemical responses of ‘Meizao’ to different thickness-dependent LDPE-MAP conditions. These observations highlight the power of the optimized PE30 packaging as an effective method for extending the fruit storage life, delaying postharvest senescence, and maintaining fruit quality of ‘Meizao’ sweet cherry.

The greasiness of 'Yuluxiang' pear rapidly increases following the transition from cold storage to ambient temperature storage, severely affecting the pear fruit's appearance and commercial value. Therefore, it is important to develop new techniques to inhibit pear greasiness during storage. In this study, 'Yuluxiang' pears were subjected to a 24 h of fumigation with 1.0 mu L L- 1 1-methylcyclopropene (MCP). Subsequently, the pears were stored at 0 degrees C for 120 and 180 d, followed by a seven-day storage at 20 degrees C. Results showed that 1-MCP postponed the onset of peel greasiness. Moreover, it slowed the cracking of the pears' cuticular wax layer and the exposure of crystal microstructure. At the same time, it inhibited the increase in the contents of (E)beta-famesene, alpha-farnesene, docosanol, stearic acid and hexadecanoic acid. 1-MCP suppressed the CO2 and ethylene production rate (EPR) of the pears during the 120 d of cold storage and the subsequent seven-day storage at 20 degrees C. Correlation analysis found a positive correlation between EPR and the content of ester compounds in the peel wax. Thus, 1-MCP may inhibit the accumulation of wax compounds and EPR, thereby suppressing the occurrence of peel greasiness. Furthermore, molecular analysis showed that 1-MCP suppressed the upregulated expression of PyLACS9 and PyFAD2 throughout the storage period, and markedly inhibited the upregulated expression of the PyACO2 during the ambient temperature storage. Since PyLACS9 and PyFAD2 play crucial roles in regulating the extension and degradation pathways of fatty acids, it was suggested that 1-MCP may suppress the accumulation of wax components and the occurrence of greasy peel by inhibiting the up-regulated gene expression of PyACO2, PyLACS9 and PyFAD2.

Laccase (LAC), a copper-containing polyphenol oxidase, is an important pathogenic factor of pathogenic fungi, and has been identified as an important virulence factor in numerous pathogenic fungi. LAC is encoded by a gene family and belongs to the class of multicopper oxidases. The study aimed to identify the LAC genes in Athelia bombacina (Link) Pers, and their interactions with the host. The expression levels of the LAC genes were quantified using RT-qPCR. The LAC activity, level of malondialdehyde (MDA) and activities of protective enzymes in ‘Huangguan’ pears during the interaction were measured. The AbLac4 gene deletion mutant strain was constructed. Six LAC genes were identified in A. bombacina, distributed across three chromosomes. Interspecies collinearity analysis suggested that LAC genes could serve as crucial pathogenic factors in A. bombacina. The LAC gene family can be classified into three distinct subgroups. Among the subgroups, variations were observed in their characteristic sequences and conserved motifs. However, the LAC genes within the same subgroup exhibited a high degree of conservation. The genes showed diverse expression profiles, with their promoters harboring multiple stress-responsive elements. Signal peptide prediction showed that all LAC proteins, with the exception of the AbLac3 protein, possessed signal peptides, indicating that they are secretory proteins. The subcellular localization analysis showed that all LAC proteins may be localized extracellularly. RT-qPCR revealed differential expression patterns among LAC genes; specifically, AbLac1 and AbLac4 exhibited distinct expression dynamics during the infection process. The LAC activity first increased and then decreased, with the highest increase rate occurring in the early stage of culture. The MDA content and catalase (CAT) activity at the inoculated site were found to be significantly higher than the uninoculated control. In addition, the deletion of AbLac4 gene reduced the growth rate and pathogenic ability of A. bombacina. This investigation found that AbLac1 and AbLac4 may play pivotal roles in mediating host interactions, and the fruit may combat pathogen infection through increasing the activities of CAT, phenylalanine ammonia lyase and peroxidase. This study provides valuable new insights into the pathogenic mechanisms of A. bombacina, significantly contributing to the field.

Aroma in food plays an important role in food perception and acceptance, which depends on various mixtures of volatile organic compounds (VOCs). Moreover, VOCs are of great significance for aroma identification. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC-MS) technology was used to determine the VOCs in 10 pear syrups. A total of 127 VOCs were quantitatively determined, including 9 common VOCs and 46 characteristic VOCs of 10 pear syrups. The pear syrups were divided into three categories by cluster analysis, and thirty-eight differential VOCs were obtained using orthogonal partial least squares discrimination analysis (OPLS-DA) and fourteen key VOCs were selected by odor activity value (OAV). It was revealed that the key and common aroma components of pear syrups were butanoic acid, methyl ester, 2-methyl-, methyl ester and Hexanoic acid, and ethyl ester. The characteristic and differential VOCs were 10-Undecen-1-ol, Hexadecanal, n-Propylacetate, Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1S,2R,5S)-, Methional, Disulfide, dimethyl, 8-Nonenoic acid, ethyl ester, Naphthalene, 1,2-dihydro-1,1,6-trimethyl-, 3H-Purin-6-amine, N,N,3-trimethyl-, 2-Octanol,2,6-dimethyl-, Furyl hydroxymethyl ketone, Heptane, 2,2,4,6,6-pentamethyl-, and Butanoic acid,2-methyl-,methyl ester. The above results showed that different pear syrups had rich diversity in aroma compounds, with some components being shared among them while others are exclusive to specific syrups.

分析比较了不同气体组分(02浓度:5％、10％;CO2浓度:1％、3％、5％)对云和雪梨贮藏品质和生理病害发生的影响.结果表明:5％02+1％CO2和10％02+1％CO2处理均较好地维持了果实品质,贮藏180、240 d及货架7d,果实硬度和可滴定酸含量均高于其他处理,且可较好地维持果皮组织中的叶绿素生物活性;而3％CO2、5％CO2处理的果实贮藏180 d后,乙醇含量和褐变指数均显著升高,且乙醇积累与生理褐变发生规律一致.综上,生产中建议云和雪梨适宜的气调参数为:02浓度5％～10％,CO2浓度≤1％.

In order to clarify the fruit quality of the main planting area of'Nanguo'pear,provide data reference for the rational and efficient utilization of'Nanguo'pear resources,and also provide reference for the cultivation of excellent pear varieties,eight'Nanguo'pear regions in Anshan were selected as the research objects.The contents of 17 mineral elements in'Nanguo'pear were determined by inductively coupled plasma-atomic emission spectrometry(ICP-AES),the contents of 4 kinds of soluble sugars were determined by ion chromatograph,and the contents of 5 kinds of organic acids were determined by liquid chromatograph.The results showed that P,K,Ca and Mg contents were the highest in'Nanguo'pear in the 8 regions,accounting for more than 97％of the total elements,while Ni,V,Co,Sr,Pd and Ag contents were lower.However,the order of mineral elements contents was different in'Nanguo'pear fruits from different regions.The average content of 4 kinds of soluble sugars in the 8 regions was ranked as fructose＞glucose＞sucrose＞sorbitol.The average content of 5 kinds of organic acids was ranked as citric acid＞malic acid＞guanic acid＞shikimic acid＞fumaric acid.There were differences in the content of quality indexes in the 8 regions of'Nanguo'pear,but all of them followed the principle that the mineral elements were mainly P,K,Ca and Mg,the contents of soluble sugars and organic acids were the highest in fructose,glucose,citric acid and malic acid.

Pear is a fruit crop of worldwide importance and cold storage is an integral part of the production and distribution of pears. An uncharacterized fungal disease has been observed on ‘Huangguan’ pear fruit during cold storage in Hebei Province. The fungus was consistently isolated from diseased fruit by routine tissue separation method, and shown to be the causal agent according to Koch postulates. Based on its morphology, molecular characteristics, pathogenicity and ITS sequence, the fungus was identified as Rhizoctonia solani. This study recorded postharvest fruit rot caused by Rhizoctonia solani on pear fruit in China.

以塞外红苹果为试材,运用高效液相色谱法(HPLC)测定不同成熟度果实在常温贮藏过程中的糖酸组分及含量,分析其动态变化和相关性,为合理贮藏提供参考依据.结果表明:随着贮藏时间的延长,塞外红果实的果糖和蔗糖占比最大,二者共可占总糖的60％以上;最主要的有机酸是苹果酸,占总酸的97％以上,其次是柠檬酸.在贮藏期间,七成熟塞外红果实的糖组分含量均呈上升趋势,九成熟果实除了蔗糖含量和山梨醇含量呈下降趋势外,葡萄糖含量和果糖含量呈上升趋势,这可能是因为山梨醇和蔗糖在果实成熟期间转化为果糖和葡萄糖;除七成熟果实柠檬酸含量呈先上升后下降趋势外,其他有机酸含量在不同成熟度果实中均呈下降趋势.相关性分析发现,葡萄糖含量和苹果酸含量分别与总糖含量和总酸含量相关性最强,相关系数分别为0.866、0.998,二者构成塞外红果实糖酸的最重要部分.综合分析认为,九成熟塞外红果实食用最佳货架时间是9 d,而七成熟果实在货架12 d左右食用最佳.

以库尔勒香梨为试材,研究1-MCP处理对果实常温贮藏[(20±1)℃]的保绿效果和内在品质的影响.结果表明:随着贮藏时间的延长,库尔勒香梨果皮颜色逐渐褪绿转黄,果实硬度和可溶性固形物、可滴定酸、维生素C含量均呈下降趋势.1-MCP处理的L*值和b*值均低于对照,h.值高于对照,贮藏第20～30 d,a*值低于对照.1-MCP处理抑制了可滴定酸、维生素C含量的下降速率,推迟了库尔勒香梨常温贮藏期间的呼吸高峰,并显著抑制乙烯释放速率.贮藏第30d,1-MCP处理种子颜色指数低于对照,果柄保鲜指数在整个贮藏期间均高于对照,果皮和果心相对电导率始终低于对照.相关性分析结果表明,贮藏期间果实乙烯释放速率与贮藏天数、果皮颜色(L*、a*、b*值)均呈显著正相关,与h.值、果柄保鲜指数均呈显著负相关;果柄保鲜指数与贮藏天数、a*值呈显著或极显著负相关,与h.值呈显著正相关.综上,采用1.0μL/L1-MCP熏蒸处理12h,能够维持库尔勒香梨常温贮藏下的果皮绿色和果实内在品质,有效延长常温贮藏寿命.

研究了不同采收期盖县大李果实在常温(20±1)℃货架7 d条件下品质的变化.结果表明,随着采期的延后和货架期的延长,果实可溶性固形物含量、固酸比、a*值、黏附性、内聚性和弹性上升,可滴定酸含量、L*值、b*值、破裂力、屈服力、胶黏性和咀嚼性下降.7月13日采收的果实硬度较高,品质较差,着色程度低;而7月27日采收的果实硬度过低,质地太柔软,无法运输,但品质较高,适合即采即食,观光采摘;7月20日采收的果实品质最佳,硬度适中,可溶性固形物含量更接近7月27日采收的,颜色较鲜艳.因此,建议在辽宁省盖县大李在7月20日采收,采收时果实硬度在4.50-5.00 kg/cm2,可溶性固形物含量不得低于11.00％,果皮底色为黄绿色,果面一半转红,更适合鲜果销售.

黄冠梨果实用0.5、1.0μL/L 1-MCP(l-甲基环丙烯)处理,以不用1-MCP处理的果实为对照,以上果实均置于(0±0.5)℃条件下贮藏,分别于冷藏40、80、120d以及对应货架7 d时进行生理指标测定,研究不同浓度1-MCP处理对黄冠梨贮藏品质的影响.结果表明,与对照相比,1-MCP处理有效地抑制了果实硬度、可滴定酸含量、果皮h.值以及果皮叶绿素含量的下降,延缓了果实可溶性固形物含量、果皮L*值的上升.综合果实外观品质和内在品质,生产中建议黄冠梨贮藏前进行1.0 μL/L 1-MCP熏蒸16 h处理以延长贮藏时间.

以鞍山市8个产区南果梨果实为研究对象,采用顶空固相微萃取-气相色谱质谱联用技术,对8个产区南果梨果实香气成分及含量进行测定,利用主成分分析和香气强度值(OAV)筛选出关键香气成分和特异香气成分,通过层次聚类分析进行产区分类.结果表明,8个产区南果梨果实共检测出香气成分109种,包括酯类、醛类、醇类、酮类和其他.南台镇产区南果梨果实香气成分数量最为丰富(77种),什司县镇产区南果梨果实香气成分数量最少(61种),王石镇产区酯类香气成分含量最高,占其香气成分总量的92.02％;共鉴定出58种关键香气成分,15种特异香气成分;根据层次聚类分析将8个产区南果梨果实分为三大类,分别为低香气型南果梨产区(什司县镇、马风镇产区)、高醛型南果梨产区(大屯镇、接文镇、海城市、鞍山市、南台镇产区)和高酯高酮型南果梨产区(王石镇产区).南果梨果实香气成分以酯类最为丰富且含量最高,共有特异香气成分9种,主要呈香物质没变,但因园区管理差异和气候等均会引起南果梨果实香气成分的呈香差异.

选取梨不同品种果实为研究对象,分析不同梨品种品质指标差异,筛选出影响梨品质的关键指标,并根据品质指标对60个梨品种进行分类.结果表明,通过相关性分析得出,不同梨品种果实各项品质指标存在差异,前4个因子特征值均大于0.9,累积贡献率达78.35％.第1主成分味道因子,其大小主要由可溶性固形物(SSC)、可滴定酸(TA)、pH值、乙醇和乙醛决定;第2主成分甜酸度因子,其大小主要由固酸比(SSC/TA)决定;第3主成分粗糙度因子,其大小主要由石细胞含量决定;第4主成分质量因子,其大小主要由单果质量决定.10个品质指标中有7个指标对前4个因子贡献率最大,包含了大部分信息,因此,筛选SSC、TA、SSC/TA、pH值、石细胞、乙醇和乙醛作为梨品质的关键指标.聚类分析将60个梨品种分成3大类.综合分析得出,不同梨品种品质存在一定的差异,但各品质指标存在一定的相关性,并且同一栽培梨系统的梨品种不一定具备相同的品质特点.