鲜枣贮藏过程中维生素C含量变化规律的研究

鲜枣贮藏过程中维生素Ｃ含量先下降,后略上升又下降;不同品种、不同成熟度、不同采后处理方法,对贮藏过程中维生素Ｃ含量变化规律的影响不同,速冻和热处理对Ｖｃ有破坏作用。脆果率高、贮藏效果好的处理维生素Ｃ含量也高,因此鲜枣贮藏过程中脆果率的高低可作为维生素Ｃ保存效果的指标。     

冰温保鲜对新疆鲜枣贮藏品质的影响

为探讨冰温贮藏条件对鲜枣品质的影响,以新疆若羌冬枣为试材,将其分别置于0℃冷藏(CK)、-1.5～-1.0℃冰温贮藏,分别测定了贮藏过程中冬枣的失重率、腐烂率、硬度、色差、可溶性固形物含量、果胶含量、多聚半乳糖醛酸酶(PG)、果胶甲酯酶(PME)、β-半乳糖苷酶(β-Gal)活性。结果表明:随着贮藏时间的延长,冰温贮藏枣果失重率的上升、色差的变化程度及可溶性固形物含量的下降均得以延缓;对0℃冷藏的枣果来说,其硬度的下降更快,PG、PME、β-Gal活性也随之升高,而冰温贮藏则抑制酶活性的升高速率,降低枣果实腐烂变质和衰老软化的进程,有效延长若羌冬枣的贮藏期。     

1-MCP对鲜枣采后生理及保鲜效果的影响

鲜枣(ZizphusjujubaMill.大平顶)采用1.00uL·L-1浓度1-MCP(1-甲基环丙烯)在15℃条件下熏蒸处理12h,之后,在0℃和20℃温度下贮藏。结果表明:1-MCP促使全红果呼吸增强,对半红果影响不大;1-MCP抑制半红果VC含量的下降,但加速全红果VC的损失;常温下(20℃)1-MCP对枣果脆果率影响不大,在0℃条件下,半红果处理脆果率明显高于对照,但促使全红果变软,贮藏30天,处理半红果脆枣率比对照高17.1%,全红果比对照低6.9%;处理半红果烂果率高于对照,全红果则相反。1-MCP有助于果皮叶绿素的保持。总体上,1-MCP处理对枣果SSC、可溶性糖、乙醇和TA等的影响不明显。     

绵毛优若藜的抗逆性研究初报

绵毛优若藜是美国特有种,2001年引入民勤植物园后,为了大面积推广,对其适应性进行了观测试验。采用盆栽和田间试验,测定沙土和粘土的绵毛优若藜的萎蔫系数;用盆栽试验比较绵毛优若藜的耐盐能力。田间试验测得的沙土和粘土的绵毛优若藜的萎蔫系数分别为1.25%和2.96%。当硫酸盐-氯化物型沙壤土的全盐量超过8.03g/kg,绵毛优若藜表现盐害。盐渍对绵毛优若藜危害较单盐溶液更大。绵毛优若藜受盐胁迫,叶色变谈的同时,呈铁锈红;在干旱胁迫下其叶色只是变谈。     

自制保鲜剂对灵武长枣低温贮藏保鲜效果的研究

以可溶性固形物含量24.3%的灵武长枣为试材,研究了冷藏过程中果实品质变化及贮藏保鲜效果。结果表明,保鲜剂浸果极显著降低了霉烂果率,显著减缓了贮藏中后期果肉硬度下降和维生素C氧化分解,明显抑制了果肉蔗糖水解,显著提高了贮藏中后期脆好果率。但保鲜剂浸果对可溶性固形物、还原糖、总糖和果胶含量没有明显影响。脆好果率与果肉硬度、抗坏血酸含量和蔗糖含量均呈极显著正相关性,拟合曲线为二次多项式,相关系数分别为0.9266、0.9937和0.9971。果肉抗坏血酸含量和果肉硬度均与蔗糖含量呈极显著正相关性,相关系数分别为0.9894和0.9343。     

真空渗透钙离子和植物激素对灵武长枣贮藏

以生长后期全红灵武长枣为试材,研究了真空渗透Ca2 和植物激素对果实在低温贮藏过程中品质以及硬好果率的影响.试验结果表明:Ca2 和Ca2 植物激素真空渗透显著降低了果实在贮藏过程中维生素C的氧化分解,贮藏结束时(60d)维生素C含量提高了33.1%;处理的硬好果率平均达90.9%,比对照净增加了30.4%,但处理之间没有明显的差异.同时,Ca2 和Ca2 植物激素真空渗透对果肉硬度、可滴定酸含量、可溶性固形物含量、水溶性总糖含量和可溶性果胶含量没有明显影响.值得注意的是:全红灵武长枣真空渗透Ca2 和Ca2 植物激素后有大约5%的枣果裂口,影响了果实的外观.     

真空渗透钙离子和植物激素对灵武长枣贮藏保鲜效果的影响

以生长后期全红灵武长枣为试材,研究了真空渗透Ca2+和植物激素对果实在低温贮藏过程中品质以及硬好果率的影响。试验结果表明：Ca2+和Ca2++植物激素真空渗透显著降低了果实在贮藏过程中维生素C的氧化分解,贮藏结束时（60天）维生素C含量提高了33.1%;处理的硬好果率平均达90.9%,比对照净增加了30.4%,但处理之间没有明显的差异。同时,Ca2+和Ca2++植物激素真空渗透对果肉硬度、可滴定酸含量、可溶性固形物含量、水溶性总糖含量和可溶性果胶含量没有明显影响。值得注意的是：全红灵武长枣真空渗透Ca2+和Ca2++植物激素后有大约5%的枣果裂口,影响了果实的外观。     

采收期和品种对枣果实品质的影响*

以灵武长枣、冬枣和梨枣为试材,研究了不同采收期对灵武长枣果实品质的影响;以及在同一采收期下,灵武长枣、冬枣和梨枣在低温贮藏前后营养成分的变化规律。试验结果表明：灵武长枣在不同的采收期中,全红果的果肉硬度小于大半红果,头蓬果高于三蓬果;全红果的可溶性固形物、蔗糖、可溶性果胶含量均高于大半红果;三蓬果的葡萄糖、果糖含量高于头蓬果,头蓬全红果的蔗糖、总糖含量高于三蓬全红果;抗坏血酸含量在各个采收期变化不明显。同一采收期的灵武长枣、冬枣和梨枣,在贮藏95 d后,3个品种的果肉硬度、抗坏血酸、可溶性固形物、蔗糖、总糖均呈下降趋势,其中梨枣的果肉硬度、抗坏血酸含量下降均最多;灵武长枣采收时抗坏血酸含量最高且降解最少;冬枣蔗糖含量下降了88.5个百分点;灵武长枣、冬枣可滴定酸含量有所增加,而梨枣出现下降;冬枣的果糖上升了113.6个百分点,明显高于其它两个品种,是贮藏后风味更为浓甜的主要原因。     

不同贮藏条件对赞皇大枣采后生理的影响

研究了不同贮藏条件下半红赞皇大枣的采后生理变化和贮藏效果。结果表明,赞皇大枣属于非呼吸跃变型果实;在贮藏过程中Vc含量逐渐降低,乙醇和MDA含量前期缓慢上升、后期上升加快,PG酶和淀粉酶活性逐渐降低。与冷藏相比,气调贮藏对保持枣果品质效果更好。     

不同处理方法对冬枣贮藏效果的影响

为探讨新疆地区所产冬枣在不同处理方式下的贮藏效果,试验在-0.5~0.5℃冷藏条件下,研究了1包萎霉灵溶液浸泡、50%仲丁胺溶液熏蒸、1-MCP处理等方式对冬枣贮藏效果的影响。结果表明:将带有叶子和枣吊的冬枣,采用0.01%萎霉灵溶液浸泡1 min,沥干浮水后装入打孔PVC保鲜袋,袋内放置1 m L 50%仲丁胺溶液作熏蒸消毒剂和1包1-MCP处理可保持较高的好果率和脆果率,维持较高的果实硬度,延缓果实pH和TSS含量的下降,贮藏效果较好;将冬枣果实采用0.01%萎霉灵溶液浸泡1 min,沥干浮水后装入不打孔PVC保鲜袋,袋内放置1包50%的仲丁胺溶液作熏蒸消毒剂和1包1-MCP,贮藏30 d后由于袋内O2浓度低或CO2浓度高,导致果实酒软速率快,脆果率低,贮藏效果差。贮藏期间,冬枣的pH、果肉硬度逐渐降低,VC含量呈先升后逐渐下降趋势。     

不同促成栽培草莓果实品质及采后生理的研究

以不同促成栽培草莓品种果实为试材,测定其品质和果实采后生理变化,为引进新品种和延长草莓货架期提供理论依据。结果表明, “甜查理”品质和适应性最好,耐贮藏。随着贮藏时间的延长,果实硬度逐渐下降,腐烂指数逐渐增大,各品种果实呼吸速率第3d后明显增强（P<0.05）, Vc含量与SOD活性总体呈先上升后下降的变化趋势, MDA含量以及O2&#8226;-代谢速率与腐烂指数呈线性正相关,这也表明了果实腐烂与O2&#8226;-以及MDA积累有密切关系。     

不同采后处理对‘水晶蜜柚’果实品质的影响

为探究不同采后处理对水晶蜜柚品质的影响,对成熟采收的柚子进行撞击、套袋、保鲜和贮藏4个因素的试验,研究不同采后处理对‘水晶蜜柚’贮藏期间果实品质的动态变化,并对果实感官品质进行评分,探讨不同处理下柚子内在品质与感官品质的关系。结果表明,果实失重随试验时间延长而加剧,失重率1.7%~35.7%,相对于撞击处理和清水浸果处理,非撞击和咪鲜胺浸果处理可减少柚子损坏率,0.01 mm聚乙烯膜套袋处理和冷库低温贮藏可降低柚子失重。随贮藏时间推移,果实内在指标变化趋势总体一致,表现为可溶性固形物先略微增加再降低,可滴定酸先降低再增加再降低,Vc逐渐降低,木质素含量先降低再增加,且不同处理柚子可溶性固形物在19~40天达最大、木质素含量达最低。套袋和保鲜较未套袋和清水浸果处理分别增加柚子可溶性固形物133.8%和72.3%;撞击和冷库贮藏柚子可滴定酸含量较未撞击和常温贮藏处理分别增加82.4%和86.3%;套袋和冷库贮藏Vc含量分别增加17.6%和15.9%;撞击方式处理木质素含量增加85.0%,套袋、咪鲜胺保鲜和冷库贮藏处理分别降低柚子木质素34.3%、33.3%和51.7%。不同处理柚子果实感官评分随着试验时间延长呈先增加后降低的趋势,撞击加速柚子感官品质降低,较未撞击处理增加12.9%,套袋、咪鲜胺保鲜和冷库贮藏减缓柚子感官品质的降低,较未套袋、清水浸果保鲜和常温贮藏增加2.5%、7.7%和10.5%。柚子感官评价与果实内在品质存在高度一致性,随着贮藏时间的推延柚子感官评价和内在品质均呈现先增加后降低的趋势,采后1个月左右柚子品质最佳。综合而言,采取轻拿轻放、0.01 mm聚乙烯膜、咪鲜胺浸果和冷库贮藏组合处理(T1)可保持柚子的新鲜品质,并延长货架期。     

The effect of delays in establishment of a static or dynamic controlled atmosphere on the quality of ‘Hass’ avocado fruit

The effect of delays of 1, 5, 10 or 15 d after harvest in establishing a static controlled atmosphere (SCA) or dynamic controlled atmosphere (DCA) on the quality of ‘Hass’ avocados (Persea americana Mill.) was investigated. Fruit were stored at 5 °C in SCA (5% O₂/5% CO₂) or DCA (<3% O₂/0.5% CO₂) for 6 weeks and compared with fruit stored in air. In addition, to determine whether increasing the CO₂ in the DCA would affect the fruit quality, DCA-stored fruit were compared with fruit held in a DCA with 5% CO₂ (DCA + CO₂) established 1 d after harvest. The quality of fruit was assessed at the end of storage and after ripening at 20 °C. DCA-stored fruit ripened in 4.6 d compared with 7.2 d for SCA-stored fruit, or 4.8 d for air-stored fruit. In addition, the incidences of stem end rot (SER), body rot (BR) and vascular browning (VB) were lower in DCA-stored fruit (35%, 29% and 29%, respectively) than in SCA-stored fruit (57%, 52% and 49%, respectively), or air-stored fruit (76%, 88% and 95%, respectively). Delaying the establishment of both SCA and DCA for 15 d resulted in significantly more advanced skin colour at the end of storage (average rating score 11.9) compared with other delay periods (4.6–5.1). There was no significant effect of delay on the time to ripen, skin colour when ripe or any ripe fruit disorder incidence. The incidence of diffuse flesh discolouration (DFD) was not only <1% when averaged over all delays but only occurred at >0.5% incidence in the 15 d delay treatment in DCA (4.8%) and not in SCA. The incidence of diffuse flesh discolouration was 62% in air-stored fruit. Inclusion of 5% CO₂ in DCA retarded fruit ripening from 4.7 to 6.9 d and increased the incidence of rots at the end of storage from 5% to 14%, and increased the incidence in ripe fruit of SER from 30% to 56% and of BR from 27% to 55%. It is concluded that fruit quality was better after CA storage than after air storage, and that DCA storage was better than SCA. The effect of DCA is to independently reduce the time to ripen after storage and the incidence of rots when ripe. Delaying the application of SCA or DCA did not affect the expression of rots, but may increase the incidence of DFD. Inclusion of CO₂ at 5% in CA retarded fruit ripening but stimulated rot expression and should not be used for CA storage of New Zealand grown ‘Hass’ avocados.     

Residual effects of low oxygen storage of mature green fruit on ripening processes and ester biosynthesis during ripening in bananas

Mature green banana (Musa sapientum L. cv. Cavendish) fruit were stored in 0.5%, 2%, or 21% O₂ for 7 days at 20 °C before ripening was initiated by ethylene. Residual effects of low O₂ storage in mature green fruit on ripening and ester biosynthesis in fruit were investigated during ripening for up to 6 d at 20 °C. Concentrations of ethanol in mature green fruit did not change during storage in both 21% and 2% O₂ atmospheres, but increased in fruit stored in 0.5% O₂. The activities of alcohol dehydrogenase (ADH) in 2% and 21% O₂ atmospheres remained very low throughout the storage period, but significantly increased with 0.5% O₂. After transferring fruit to regular air and trigging ripening with ethylene, yellowing of peel, fruit softening and hydrolysis of starch in fruit stored in low O₂ atmospheres were slower than in the control. Fruit stored in low O₂ also showed a delayed onset of the climacteric peak. The activities of ADH were lower in the low O₂ stored fruit than in the control fruit. Productions of ethyl acetate, isoamyl acetate, and isobutyl acetate were remarkably suppressed by low O₂ storage. Alcohol acetyltransferase activity increased gradually with storage time in all treatments, being significantly lower in fruit with low O₂ pretreatments. The results indicate that low O₂ plus room temperature storage can extend storage life of bananas with the sacrifice of a low production of ester volatiles.     

Effect of harvest maturity on quality of fresh-cut pear salad

Texture of an unripe pear is firm and crisp, similar to an apple. However, at the crisp stage, the flavor of pears is flat. This study evaluated the effect of harvest maturity on the quality of fresh-cut pear salad. Fruit were harvested at commercial maturity and 1-month delayed. After 2 and 5 months (1 and 4 months for delayed-harvest fruit) storage at ?1 °C, fruit were sliced into 8–12 wedges per fruit, dipped in an antibrowning solution, packaged in Ziploc bags and stored at 1 °C for up to 21 d. Delayed-harvest fruit were larger in size (≈20% increase in weight), had lower flesh firmness (≈17% decrease), lower titratable acidity content (≈20% decrease), and lower phenolic content (≈45% and 13% decreases in pulp and peel, respectively). There was no significant difference in soluble solids content. After 2 months storage, ethylene production and respiration rate were initially lower in the slices from delayed-harvest fruit, but tended to become similar after 7 d in storage at 1 °C. Delayed-harvest fruit had lower hydroxycinnamic acids and flavanols, and higher ester, alcohol, and aldehyde volatile compounds after 2–5 months storage. The results indicated that fruit salad produced with delayed-harvest pears had less browning potential and better flavor. Sensory evaluation results showed that about 80% of the panel liked slices from delayed-harvest fruit over commercial harvested, especially in terms of visual quality (65–85%), sweetness (75–95%), taste (70–80%), and overall quality (75–80%) during 21 d storage at 1 °C. The cut surface of slices appeared dry in delayed-harvest fruit when processed after 5 months in storage. However, sensory evaluation showed that panels still preferred the delayed-harvest fruit.     

含迟熟基因rin的番茄果实货架寿命相关性状的研究

分析比较了贮藏过程中的番茄成熟突变体rin材料L2与正常成熟番茄品种L5及其杂种一代L20果实的果实硬度、呼吸强度、番茄红素、贮藏指数及各种商品品质的差异。结果表明:番茄果实贮藏过程中果实硬度呈下降趋势;而果实的可溶性固形物、可溶性糖、Vc、番茄红素含量变化呈上升趋势,但是有机酸含量变化总体上呈现下降趋势,因此果实的糖酸比呈上升趋势;呼吸高峰的出现有很大的差异,L2的波动较小,且呼吸强度一直处于最低状态;rin番茄果实的贮藏指数最高,达到75%以上,而正常成熟的番茄贮藏指数最低,仅60%左右,含迟熟基因的品种与正常品种杂交后贮藏性显著下降,但比正常成熟番茄耐贮,贮藏指数比正常成熟的高约15%。     

低温结合GABA处理对樱桃番茄果实采后品质的影响

探讨低温贮藏结合GABA处理对樱桃番茄果实采后品质的影响,为寻找樱桃番茄采后保鲜新技术提供理论依据。本研究以‘粉娇’樱桃番茄为试材,设置清水浸渍+常温(25℃)贮藏、清水浸渍+低温(8℃)贮藏和GABA(500 mg/L)浸渍+低温(8℃)贮藏3个处理,在樱桃番茄16天的贮藏期内,调查果实腐烂率,测定果实呼吸强度、果实硬度、可溶性固形物、维生素C、柠檬酸和类胡萝卜素含量。结果表明,与常温(25℃)贮藏相比,低温及其结合GABA处理均显著降低了樱桃番茄果实贮藏期间的腐烂率,其中在贮藏16天时,防治效果分别达到了45.81%和63.11%,低温结合GABA处理优于单独低温贮藏。同时,低温结合GABA处理显著降低了果实的呼吸强度,延缓了果实硬度的降低,保持了较高的可溶性固形物、维生素C和柠檬酸含量,抑制了番茄红素、β-胡萝卜素和叶黄素的积累。因此,低温结合GABA处理可有效延缓樱桃番茄果实的腐烂和衰老,并能保持果实的采后品质,在樱桃番茄果实保鲜上具有良好的应用前景。     

库尔勒香梨采后特征品质的研究

摘要：库尔勒香梨贮藏在0℃、5℃、10℃、15℃、20℃,相对湿度：90～95%的环境中,测定香梨在贮藏过程中果实硬度、可溶性固形物含量及果皮色泽的变化,采用数值的极差及变异系数,研究采后库尔勒香梨的特征品质。结果表明：香梨采后贮藏于不同温度下,其硬度随着果实的成熟均呈现下降趋势,低温贮藏对硬度的下降有明显的抑制作用;可溶性固形物在不同贮藏温度下降不明显,特别是低温贮藏;果品色泽在各贮藏温度下,随着贮藏时间的延长,成熟度增加,有显著的变化。比较香梨果实硬度、可溶性固形物、色差的在整个贮藏期间的变化差异,色差的数值变化最为明显,对香梨采后品质及衰老具有明显的指示作用,可作为评价香梨果实采后品质变化的特征指标及采后衰老的重要指标。     

壳寡糖处理对草莓贮藏品质的影响

以草莓为试材,果实采后,分别用质量分数为1.0%,1.5%,2.0%的壳寡糖溶液浸泡处理草莓果实1min,研究壳寡糖处理对草莓贮藏品质的影响。结果表明,壳寡糖处理能较好地保持贮藏草莓的感官品质、风味品质、营养品质;能有效调节、控制果肉细胞的成熟与衰老,从而延长果实贮藏期。质量分数1.5%壳寡糖处理果实的各项品质指标均优于其他处理组,是有效延长草莓果实贮藏时间的最佳浓度。     

贮前外源水杨酸处理对桃果冷贮性的影响

选择商品成熟期的桃(Prunus persica L. cv. Beijing 24),采摘后分别用0、0.35、0.7、1.0 mmol/L 水杨酸 （Salicylic acid,SA）溶液浸泡5 min,在0℃的低温下贮藏28d,然后转到20℃下3d（模拟货架期）。货架期结束时,观察果实冷害和腐烂发生状况并计算果实冷害指数和腐烂指数,测定果实的硬度和丙二醛含量。结果表明,与对照相比,1 mmol/L SA处理对维持果实硬度具有显著的效果,同时显著降低了冷害指数、腐烂指数和丙二醛含量,其他两种浓度的SA处理与对照之间不存在显著差异。说明1 mmol/L SA能够减轻桃果的冷害。进一步研究发现,在冷藏中期（14d）、冷藏结束时（28d）和货架期结束时,1 mmol/L SA预处理的桃果肉的还原性抗坏血酸与氧化性抗坏血酸含量之比(AsA/DHAsA)分别比对照高39%,61%和55%。在冷藏中期（14d）,还原性谷胱甘肽与氧化性谷胱甘肽含量之比(GSH/GSSG) 比对照高68%。在贮藏和货架期结束时,抗坏血酸氧化酶和谷胱甘肽还原酶活性显著高于对照。上述结果说明,水杨酸能减轻桃果由于冷贮发生的冷害与诱导提高抗氧化系统抗抗坏血酸—谷胱甘肽循环的活性有关,适宜浓度的水杨酸处理可能是提高桃果实冷藏性的有效措施。