气调冷藏对龙眼保鲜品质的影响

以提高龙眼果实保鲜质量为目的,采用可控气体成分调节方法,温度、湿度和气体成分全自动控制,以普通冷藏为对照对龙眼进行气调保鲜。研究了气调冷藏对龙眼果实保鲜效果、果实营养成分及理化指标的影响。结果表明,通过降低贮藏环境中的O2含量,提高CO2浓度,可有效抑制龙眼果实的呼吸作用,延缓了果实的衰老与变质,保鲜效果好,商品率高。     

可食性魔芋葡甘聚糖膜对龙眼保鲜研究

用可食性魔芋葡甘聚糖膜对“乌龙岭”龙眼进行处理后，分别置于常温（２９～３１℃）和低温（３℃）下保鲜，并着重研究了其保鲜效果。试验表明：常温保鲜１０天后龙眼的好果率达８２．８６％，失重率为２．５６％；低温保鲜６０天后龙眼的好果率达８８．８９％，失重率为２．０３％。两者的祸变率均低于对照组，基本上防止了果皮失水、褐变，果肉长霉、腐烂变质，保持龙眼原有风味，延长了贮藏期和货架寿命。     

不同剂量Na2S2O5缓释制剂对龙眼冷藏效果的影响

适宜剂量Na2S2O5缓释制剂处理结合低温贮藏,能有效地抑制龙眼果实呼吸强度和果皮PPO活性,延缓果实衰老变质,延长贮藏寿命。贮藏60天果皮色泽淡黄,无褐变,好果率达97%以上。     

壳聚糖包膜龙眼对其果皮生理生化特性的影响

以不同浓度的脱乙酰壳聚糖为主要原料,研究其在常温下(28~37℃)对"乌龙岭"龙眼的保鲜效果及其对龙眼果皮生理生化特性的影响。结果表明,经壳聚糖包膜的龙眼贮藏后,龙眼的褐变率、腐烂率和失水率明显降低,且可保持较高的商品率;此外包膜后,龙眼果皮的细菌和真菌数量受到抑制。进一步分析发现,包膜处理龙眼,可减缓其果皮叶绿素含量的减少,抑制龙眼果皮相对电导率、多酚氧化酶活性和胡萝卜素含量的上升。当脱乙酰壳聚糖的体积分数为95%时,对龙眼的保鲜效果最好。     

果实果皮研究进展

果皮是果蔬最直观的品质性状,也是衡量果实商品价值的重要指标之一.笔者从生理生化和分子机制角度叙述了果皮颜色变化的原理.简述了果皮色素抗癌、抗氧化等保健功能和目前常见的3项天然色素提取工艺.总结了果皮褐变机理和生长调节剂对果皮褐变的调控效果.今后可将新型复合包装材料与褐变抑制剂相结合的手段用于果实采后贮藏保鲜.目前调控黄...     

气调处理对“早生新水”梨果实贮藏品质的影响

为研究气调环境对冷藏和货架期间早生新水’梨果实贮藏品质的影响,筛选其适宜的气调贮藏技术参数,对其冷藏和货架期间果实失重率、腐烂率、糖、酸、叶绿素含量及果皮色差进行测定。结果表明：低温冷藏60d,货架期3d,对照果实果皮和果心出现褐变,固有风味降低。处理Ⅴ的梨果实冷藏和货架期间果皮、果肉和果心严重发黑、果肉呈水渍状,果皮有汁液溢出。适宜比例的O 2、和CO 2气体配比组合可抑制冷藏和货架期间果实糖损耗和果实褐变。综合得出：1% CO2、8% O2 和92%N2 的气体配比（处理Ⅲ）可显著降低冷藏期间果实带皮硬度的下降速率,抑制果实葡萄糖、果糖和山梨醇的降解、以及果实果皮叶绿素尤其是叶绿素b的降解或氧化,延缓果实褐变,较好的保持果实固有风味;较好地保持货架期间胚乳的完整、色泽和果实固有风味,抑制果肉褐变。1% CO2、8% O2 和92%N2的气体配比结合温度为1±0.5 ℃、相对湿度为80%-85%的冷藏参数,可使果实的冷藏期延长至60d,货架期3d。     

浸钙、壳聚糖浸泡和温烫处理对台湾青枣果皮褐变的影响

为了探索抑制台湾青枣(Ziziphus mauritiana Lamk.)果皮褐变的绿色冷藏保鲜前处理技术及其抗活性氧损伤的生理机理,采用正交试验设计法,对台湾青枣果实经过浸钙、壳聚糖浸泡和温烫处理,探讨3因素处理后对冷藏台湾青枣果皮褐变的影响。结果表明：浸钙和温烫处理能抑制果皮褐变和降低果皮丙二醛(MDA)含量,而壳聚糖浸泡处理则加剧果皮褐变和提高果皮MDA含量;浸钙和温烫处理抑制果皮PPO活性,而壳聚糖浸泡处理则提高了果皮PPO活性;浸钙和温烫处理能提高果皮SOD和POD活性,壳聚糖浸泡处理则抑制了果皮SOD和POD活性;3因素处理对果皮CAT活性无抑制作用,在高峰期还呈现提高果皮CAT活性的效果。可见,浸钙和温烫处理能改善台湾青枣果实贮藏效果和减轻果皮活性氧损伤。     

Simulation of Concrete Meso-Failure Process with Meso Element Equivalent Method

综述了桃果实的采后贮藏特性及贮运中容易出现的软化、低温伤害、果肉褐变与絮败、风味丧失及腐烂等品质劣变发生机理的研究进展,从低温、气调、冰温、减压、变温贮藏和外源物质处理等多方面介绍了其预防技术的研究现状,并展望了桃果实保鲜技术研究的未来发展趋势。     

气调处理对‘早生新水’梨贮藏品质的影响

为研究气调环境对冷藏和货架期间‘早生新水’梨果实贮藏品质的影响,筛选其适宜的气调贮藏技术参数,对其冷藏和货架期间果实失重率、腐烂率、糖、酸、叶绿素含量及果皮色差进行测定。结果表明:低温冷藏60天,货架期3天,对照果实果皮和果心出现褐变,固有风味降低。处理Ⅴ(1%O_2,5%CO_2,94%N_2)的梨果实冷藏和货架期间果皮、果肉和果心严重发黑、果肉呈水渍状,果皮有汁液溢出。适宜比例的O_2和CO_2气体配比组合可抑制冷藏和货架期间果实糖损耗和果实褐变。综合得出,1%CO_2、8%_和92%N_2的气体配比(处理Ⅲ)可显著降低冷藏期间果实带皮硬度的下降速率,抑制果实葡萄糖、果糖和山梨醇的降解,以及果实果皮叶绿素尤其是叶绿素b的降解或氧化,延缓果实褐变,较好地保持果实固有风味;较好地保持货架期间胚乳的完整、色泽和果实固有风味,抑制果肉褐变。1%CO_2、8%O_2和92%N_2的气体配比结合温度为(1±0.5)℃、相对湿度为80%~85%的冷藏参数,可使果实的冷藏期延长至60天,货架期3天。     

“储良”和“石硖”龙眼果实采后品质变化和贮藏性比较

以海南省龙眼主栽品种"储良"(CL)和"石硖"(SX)为试材,比较了两种龙眼种子的大小、果皮和果肉厚度、果皮色泽等外观品质特性。并分别在冷库(6±1)℃、相对湿度75%、内衬有孔塑料袋纸盒外包装的条件下贮藏17 d,测定和分析了2种龙眼的低温贮藏性能。结果表明,SX果实较小、果皮厚且粗糙、果肉清脆;CL果实较大,果皮薄且光滑,果肉绵软。采后低温贮藏期间,SX龙眼果肉可滴定酸(TA)含量变化较缓慢,贮藏17 d时,SX龙眼果实好果率、果肉可溶性固形物含量(SSC)、VC、还原糖含量显著高于CL果实(P0.05),SX果实呼吸强度、果皮相对电导率、丙二醛(MDA)含量、果肉褐变度、多酚氧化酶(PPO)活性和过氧化物酶(POD)活性均低于CL果实。综上所述,SX龙眼果实在耐低温贮藏方面明显优于CL龙眼果实。     

Phomopsis longanae Chi-induced pericarp browning and disease development of harvested longan fruit in association with energy status

The effects of Phomopsis longanae Chi infection on browning development and disease incidence in relation to energy status in pericarp of harvested longan fruit were investigated. Longan fruit were inoculated for 5 min with P. longanae at 10⁴ spores mL⁻¹, while fruit dipped in sterile deionized water were used as control. These fruits were stored at (28 ± 1) °C and 90% relative humidity for up to five days. The results showed that the browning index, disease incidence, cellular membrane permeability and AMP content increased but the contents of ATP and ADP, and energy charge decreased in pericarp of longan fruit infected by P. longanae. It was suggested that P. longanae infection caused energy deficiency in longan fruit, possibly resulting in accelerated senescence and decreased resistance to pathogen, and thus promoted browning development and disease occurrence.     

Use of chlorine dioxide fumigation to alleviate enzymatic browning of harvested ‘Daw’ longan pericarp during storage under ambient conditions

Pericarp browning reduces both the shelf-life and market value of harvested longan fruit stored at room temperature. Our study investigated the efficiency of chlorine dioxide (ClO₂) fumigation at reducing pericarp browning of longan (Dimocarpus longan Lour.) cv. Daw. Fresh longan fruit were fumigated with 0 (control), 2.5, 5, 10 and 25 mg/L ClO₂ for 10 min, before being packed in cardboard boxes, and stored at 25 ± 1 °C, RH 82 ± 5% for 7 days. Fruit treated with ClO₂ had a lower browning index, but higher hue angle (true color), L* (lightness) and b* (yellowness) values than non-treated fruit. The 10 and 25 mg/L ClO₂ treatments were the most effective at extending shelf-life from 1 to 5 days, compared with the control, by reducing pericarp browning, the activities of polyphenol oxidase (PPO) and peroxidase (POD), disease development and by maintaining the highest total phenolic content. However, quality acceptance of fruit treated with 10 mg/L ClO₂ was higher than fruits treated with 25 mg/L, as determined by odor and flavor. Consequently, ClO₂ fumigation at a concentration of 10 mg/L was considered to be the most effective treatment to reduce pericarp browning of longan, whilst maintaining fruit quality.     

添加剂对速冻龙眼裂果率的影响

通过使用添加剂减少速冻龙眼生产过程中容易出现的裂果现象,将羧甲基纤维素钠(CMC-Na)、黄原胶和复合磷酸盐作为添加剂对速冻龙眼裂果率的影响进行研究,试验结果表明,0.6%的复合磷酸盐抗冻裂效果最好。     

The role of active oxygen metabolism in hydrogen peroxide-induced pericarp browning of harvested longan fruit

Effects of hydrogen peroxide (H₂O₂), as exogenous reactive oxygen, on browning and active oxygen metabolism in pericarp of harvested ‘Fuyan’ longan fruit were investigated. The results showed that as compared with the control fruit, there was a higher browning index in pericarp of H₂O₂-treated fruit. The fruit treated with H₂O₂ resulted in increased rate of superoxide anion (O₂⁻) production, reduced activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), decreased amounts of ascorbic acid (AsA), glutathione (GSH) and carotenoid, and increased malondialdehyde (MDA) content. These results indicated that H₂O₂-induced browning in pericarp of harvested longan fruit might be due to a reducing capacity of active oxygen scavenging and an increase of accumulation of O₂⁻, which might stimulate membrane lipid peroxidation, disrupt cellular membrane structure, and cause the loss of cellular compartmentalization, in turn, resulting in the contact of polyphenol oxidase (PPO) and peroxidase (POD) with phenolic substrates and subsequently oxidation phenolics to form brown polymers.     

SO2保鲜纸结合冷库预冷对龙眼果实低温贮藏效果的影响

以"石硖"品种龙眼(Dimocarpus longan Lour cv. Shixia)果实为材料,以(5±0.5)℃冷库低温预冷,采用L9(34)正交设计,研究不同试验因素A(SO2保鲜纸复剂用量)、B(SO2保鲜纸助剂用量)、C(预冷方式)、D(预冷时长)对龙眼果实(5±0.5)℃贮藏后综合出库品质与货架商品率的影响,并采用因子分析及多因素多元方差分析处理试验数据。结果表明,贮藏35 d后,所有处理果实综合出库与货架商品率均优于对照,表现为色度值L*、a*、b*、C*和h°均趋向优质化,叶绿素和类胡萝卜素含量降低,类黄酮含量大幅增加,与果实表面呈现明亮的黄绿色相一致,而对照果实则为黑褐色;果皮膜透性均高于对照,SO2残留主要集中在果皮,可溶性固形物含量未达极显著性差异。因素A对贮藏效果影响最大,其次D,而B、C影响最小。检测指标中,ΔL*和综合出库品质差异最显著,其次综合货架失重率、果肉SO2含量和综合货架商品率。结合均值比较结果,认为A3B3C1D2是合适的处理组合,即使用"0.21%复剂用量+0.03%助剂用量+敞口预冷+预冷20 h"的处理组合结合低温贮藏,龙眼果实能够获得较好的出库与货架品质。     

不同梨果实褐变特异性分析

以黄金梨、大香水、新梨七号为试材,研究了贮藏后梨褐变不同部位酚类物质含量和种类、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性及可溶性蛋白的关系。结果表明,梨果实中的酚类物质以绿原酸为主,果实褐变与酚类物质含量和多酚氧化酶活性,特别是二者在果实中不同部位的分布特性有关。黄金梨果心与其他部位比较具有较高的酚类物质含量和PPO活性。由果皮至果心CAT活性依次降低,而果皮中POD活性极大地高于其他部位。SOD的活性与褐变的直接关系不明显。     

缓慢降温对石榴果实冷害发生及生理变化的影响

对缓慢降温处理后石榴果实在冷害温度下的生理反应进行了研究,旨在为石榴果实采后保鲜提供理论依据。以新疆大籽石榴为试材,研究了0℃低温胁迫及缓慢降温对石榴果实采后生理的影响结果表明,与0℃的低温相比,缓慢降温处理减缓石榴果皮细胞膜透性的升高以及膜脂质过氧化物丙二醛的积累,抑制了多酚氧化酶活性的增加及减少了酚类物质的氧化,明显推迟和减轻石榴果实冷害症状的发生,减轻了果皮的褐变,保持果实品质。