采前喷施拮抗菌罗伦隐球酵母对草莓保鲜效果的影响

研究采前喷施拮抗菌罗伦隐球酵母(Cryptococcus laurentii)对常温贮藏(20℃,4d)后的\     

拮抗菌罗伦隐球酵母的生长性能研究

本文研究了罗伦隐球酵母在麦芽汁中的生长性能,包括三角瓶培养及发酵罐培养的生长动态,结果表明,罗伦隐球酵母在麦芽汁培养基中能够快速生长,罗伦隐球酵母的生长没有明显的延滞期,三角瓶培养到第20h时,酵母细胞数目达到最高值,此后罗伦隐球酵母的生长进入稳定期;发酵罐培养时,从30h开始,逐步进入稳定期;罗伦隐球酵母在发酵罐中的生长会使发酵液的pH值降低。     

拮抗酵母结合热空气处理对采后海红果的保鲜效果

研究拮抗酵母结合热空气处理对提高采后海红果果实贮藏性能的效果。分别用107CFU/mL拮抗罗伦隐球酵母悬浮液浸泡处理2 min,36℃热空气处理海红果10 h以及二者结合先后处理海红果,于20℃下储藏15 d,贮藏期每3 d测定相关指标,研究不同处理对海红果果实贮藏期的保鲜效果。结果表明,热空气处理、拮抗酵母处理、先拮抗酵母后热空气处理和先热空气后拮抗酵母处理均能降低贮藏过程中海红果的失重率、腐烂率和丙二醛含量,提高SOD、CAT和POD活性,其中先热空气后拮抗酵母处理组的各项指标除POD外,其他均显著(P<0.05)优于单一处理组,表明先热空气后拮抗酵母处理海红果的保鲜效果优于单独处理方式;能明显降低果实水分和有机质的减少以及病害的发生率,提高果实抗氧化酶活性,减少丙二醛的积累,进而延缓细胞衰老,延长货架期。先36℃热空气处理10 h后107 CFU/mL罗伦隐球酵母悬浮液浸泡处理2 min是采后海红果果实保鲜处理的适宜方式。     

羧甲基纤维素诱导提高罗伦隐球酵母对采后砂糖橘抗青霉、绿霉病的生防效果

为研究羧甲基纤维素（carboxymethyl cellulose,CMC）诱导罗伦隐球酵母（Cryptococcus laurentii）对采后砂糖橘（Citrus reticulata cv. Shatangju）拮抗扩展青霉（Penicillium expansum）、指状青霉（Penicillium digitatum）所引起青霉和绿霉病的生防增效作用,本研究以市售的砂糖橘为试材,筛选0.5%（质量分数,下同）CMC培养C. laurentii抗砂糖橘果实青霉、绿霉病的最佳诱导时间,采用无菌水为对照组,0.5% CMC诱导/未诱导培养C. laurentii为处理组,探究其对砂糖橘果实抗青霉、绿霉病效果、诱导果实抗病防御体系形成及果实贮藏质量的影响。结果表明,0.5% CMC诱导C. laurentii处理抗砂糖橘果实青霉、绿霉病的最佳诱导时间为72 h,该诱导时间下,C. laurentii对青霉、绿霉病害发生的生防效果显著优于其他诱导时间（P＜0.05）。经0.5% CMC诱导培养72 h的C. laurentii（0.5% CMC-C. laurentii）所处理砂糖橘果实与其他组相比P. expansum、P. digitatum的发病率、病斑直径显著降低（P＜0.05）。此外,与对照组相比,0.5% CMC-C. laurentii浸泡处理诱导可在贮藏第8天显著提高砂糖橘果皮β-1,3-葡聚糖酶、几丁质酶、苯丙氨酸酶、多酚氧化酶活力和总酚、类黄酮含量（P＜0.05）,保持砂糖橘在贮藏期间的营养品质。因此认为,添加0.5% CMC诱导培养可提高C. laurentii生防效力,CMC培养C. laurentii处理诱导能够提高砂糖橘果实抗病防御酶活力、促进抗性物质的合成积累、抑制采后青霉、绿霉病害发生,进而维持果实贮藏品质。     

罗伦隐球酵母冻干粉在贮藏期的活性及安全性研究

罗伦隐球酵母对许多水果的采后病害具有显著的抑制作用。要想将拮抗酵母商品化，应用于水果的采后病害防治，需要得到酵母菌体干粉制剂。另外，拮抗菌的安全性是其作为水果防腐保鲜剂的前提。研究了罗伦隐球酵母冻干粉在贮藏期的活性，并对其安全性进行了急性毒理实验评价。结果表明，罗伦隐球酵母冻干粉在4℃下保存的前5个月，其活性保存较好，但第6个月，其活性失去加快。罗伦隐球酵母冻干粉制剂经小鼠急性经口毒性实验，结果证实属于实际无毒类。     

生物活性膜对草莓保鲜效果的研究

以海藻酸钠作为罗伦隐球酵母菌(Cryptococcus laurentii)的载体,制备出一种生物活性膜。采用此膜涂抹\     

生物活性膜对草莓保鲜效果的研究

以海藻酸钠作为罗伦隐球酵母菌(Cryptococeus laurentii)的载体,制备出一种生物活性膜.采用此膜涂抹"丰香"(Fragaria ×ananassa Duch.Toyonoka)草莓,并通过贮藏期间其失重率、腐烂率、硬度、丙二醛含量、花青素含量、多酚氧化酶活性变化评价此生物活性膜的保鲜效果.结果表明,添加罗伦隐球酵母的海藻酸钠膜可有效降低草莓的失重率和腐烂率,较好地保持果实的硬度,减缓花青素的生成速率,抑制多酚氧化酶活性的增高.因此本生物活性膜对草莓有较好的保鲜效果.     

苯并噻二唑结合罗伦隐球酵母对桃果采后青霉病的控制

研究了拮抗酵母菌罗伦隐球酵母与植物诱导剂苯并噻二唑(BTH)结合使用控制桃果青霉病的效果。结果显示,罗伦隐球酵母与100μg/mL的BTH结合使用时,不仅其生防效力显著提高,还可以显著提高桃果的抗性相关酶活性,包括过氧化物酶(POD)和过氧化氢酶(CAT),并且抑制了丙二醛(MDA)含量的增加。因此,BTH与罗伦隐球酵母结合使用,集成了生物防治酵母和植物生长调节剂的生物双重活性,可能成为防治桃果采后病害的一个新途径。      

羧甲基壳聚糖诱导罗伦隐球酵母对葡萄柚果实细胞壁代谢的影响

以‘里约红’葡萄柚为试材,对羧甲基壳聚糖（carboxymethyl chitosan,CMCS）、罗伦隐球酵母（Cryptococcus laurentii）以及CMCS-C. laurentii处理葡萄柚果实采后的硬度进行测定,结果显示：与对照组（无菌水处理）相比,CMCS-C. laurentii处理显著抑制了葡萄柚果实在整个贮藏期间内的果实硬度下降（P<0.05）。在此基础上,测定贮藏期间（75 d）葡萄柚果实质量损失率、细胞壁多糖物质含量和细胞壁水解酶活力并观察果实细胞壁微观结构。结果表明：CMCS-C. laurentii处理能有效维持果实内共价结合型果胶、紧密型半纤维素的含量,降低果实中水溶性果胶、离子型果胶以及松散型半纤维素的含量;并且相较于对照组,CMCS-C. laurentii处理组果实细胞壁水解酶（果胶甲酯酶、多聚半乳糖醛酸酶、纤维素酶、α-L-阿拉伯呋喃糖苷酶和β-葡萄糖苷酶）活性均受显著抑制;贮藏中后期,CMCS-C. laurentii处理的果实细胞壁结构更加稳定,胞内结构相对完整。综上所述,CMCS-C.laurentii处理能减缓采后葡萄柚果实细...     

采前喷施壳聚糖对荔枝采后腐烂的控制

荔枝采前1个月,喷施壳聚糖,有利于荔枝果皮中丁质酶及β-1,3-葡聚糖酶活性的持续累积,而且增加了果肉中有机酸含量。贮藏过程中,β-1,3-葡聚糖酶的活性及有机酸下降的速度大大降低,荔枝腐烂得到有效控制,0.05%壳聚糖比0.03%更为有效。     

Effect of chitin on the antagonistic activity of Cryptococcus laurentii against Penicillium expansum in pear fruit

This study was designed to evaluate the impact of chitin on the antagonistic activity of Cryptococcus laurentii against the postharvest blue mold rot caused by Penicillium expansum in pear fruit. The results showed that the antagonistic activity of C. laurentii obtained from the culture media of nutrient yeast dextrose broth (NYDB) amended with chitin at 0.5-1.0% was improved greatly compared with the case that without chitin. The addition of chitin to NYDB did not influence the growth of C. laurentii, however, its population was found to increase rapidly thereafter in pear fruit wounds compared to that harvested from NYDB without chitin. Moreover, the cell-free filtrate of the chitin-supplement culture media in which the yeast was incubated for 24 h emerged a direct antifungal activity against P. expansum in pear fruit wounds, with the associated high level of chitinase activity. These results suggested that the use of chitin may be an effective method to induce the antagonistic activity of C. laurentii. To our knowledge, this is the first report regarding the chitin could enhance the efficacy of postharvest biocontrol yeasts.     

采前喷壳聚糖对荔枝贮藏性能的影响

采前1个月喷施0.03%、0.05%的壳聚糖,荔枝在低温中的贮藏性能得到改善,主要归因于喷施壳聚糖使果皮中的a-1,3-葡聚糖酶及PAL酶活性增强,且贮藏中活性减低幅度平缓,使果肉中有机酸含量增加.采前喷施壳聚糖并没有改变荔枝果皮的保水能力和果皮结构.     

Effects of preharvest application of antagonistic yeast combined with chitosan on decay and quality of harvested table grape fruit

BACKGROUND: Decay caused by fungal pathogens is responsible for significant economic loss of grape fruit in vineyards worldwide. However, postharvest treatment is not advisable for this fruit owing to its thin waxy pericarp and succulent flesh, which are easily damaged. Therefore preharvest treatment even at 1 day before harvest has been considered as a promising method to control postharvest decay of table grape fruit in storage. Integrative effects of preharvest application of Cryptococcus laurentii combined with low‐concentration chitosan on decay and quality of table grape fruit during storage were investigated in this study. RESULTS: Spraying of antagonistic yeast combined with chitosan before harvest significantly reduced natural decay of fruit stored at 0 °C. Preharvest treatment stabilised polyphenol oxidase activity, increased peroxidase and phenylalanine ammonia‐lyase activities and decreased superoxide dismutase activity compared with control fruit. There was a higher ratio of soluble solid content to titratable acidity in treated fruit than in control fruit during storage. In addition, preharvest treatment affected the total phenolic content in fruit during storage. CONCLUSION: The results suggest that integrative application of C. laurentii and low‐concentration chitosan before harvest may be a promising technology to control decay of table grape fruit in storage. Copyright © 2009 Society of Chemical Industry     

草莓灰霉病拮抗酵母菌的筛选鉴定及对采后草莓品质的影响

从南京市马群草莓生产基地的草莓果实、叶片上分离筛选到一株对灰霉病具有明显抑制效果的拮抗酵母菌N1,结合生理生化特性及26S rDNA D1/D2区序列分析鉴定其为季也蒙毕赤酵母(Pichia guilliermondii)。通过用不同浓度N1菌悬液处理打孔后的草莓,发现菌悬液浓度越高,抑制效果越好,最佳浓度为5×108CFU/mL,其病斑直径比对照组小了32.3%。拮抗菌N1处理后果实于(2±1)℃、相对湿度(RH)90%～95%下冷藏,结果表明,拮抗酵母N1菌对果实酸含量无显著影响,但能保持草莓果实的光泽和硬度,维持VC含量和可溶性固形物含量,并显著减小了失重率,提高了草莓的冷藏品质,从而显著延长草莓的贮藏寿命。由此推测,该拮抗酵母菌具有很好的商业应用前景。     

草莓贮藏保鲜技术实验研究

以草果草莓为实验对象,采取2种不同贮藏条件贮藏草莓,一种条件是存于冰温库内,库内温度为-0.5℃,湿度为85%;另一种是存于冰温气调箱内,箱内气体成分为10%CO2+3%O2,温度为-0.5℃,湿度为85%。通过定期取样测试草莓的品质变化研究草莓的贮藏保鲜效果。通过42d贮藏实验研究表明:将冰温保鲜与气调保鲜技术有机结合起来,可明显延长草莓保鲜期,并且能够更好的保持营养成分和口感。     

采前喷施保鲜剂对蓝莓贮藏品质的影响

以粉蓝蓝莓为试验材料,通过采前喷施不同保鲜剂(800mg/L纳他霉素、1 000mg/Lε-聚赖氨酸、800mg/L壳聚糖),采后于(0.5±0.5)℃冷藏,研究蓝莓果实生理品质的变化。结果表明:采前不同保鲜剂处理均能降低蓝莓果实的腐烂率,延缓蓝莓鲜果的硬度、可溶性固形物含量、可滴定酸含量及花色苷含量的降低,降低蓝莓鲜果呼吸强度及乙烯生成速率,维持较好的过氧化物酶、过氧化氢酶、脂氧合酶和抗坏血酸过氧化物酶活性,并有效降低蓝莓霉菌及酵母菌的菌落总数。采前喷施800mg/L纳他霉素对蓝莓果实的贮藏效果最好,能有效抑制蓝莓的衰老进程,维持更好的贮藏效果。     

预温处理对草莓贮藏保鲜效果的影响

本试验从草莓果实贮藏期间的腐烂率入手,研究了不同贮前预温处理对草莓果实采后贮藏保鲜效果的影响。结果表明:预热处理后,无论是冷藏或室温贮藏,均以贮前50℃30min 处理的果实腐烂率最低;预冷处理后,室温贮藏条件下,以5℃30min处理的果实腐烂率最低;预冷处理和预热处理均能明显抑制果实 Vc 含量的下降。     

Synergistic effect of chitosan and Cryptococcus laurentii on inhibition of Penicillium expansum infections

This study was conducted to determine the efficacy of chitosan at different concentrations with various intrinsic viscosities alone, and in its combination with a yeast antagonist Cryptococcus laurentii in reducing the blue mold rot caused by Penicillium expansum in apple fruit. The results indicated that application of chitosan alone was effective in inhibiting the blue mold rot in apple fruit wounds, especially with the high concentrations and low viscosities. But its efficacy was declining with the incubation time so that chitosan alone could not provide enduring protection of apple fruit from P. expansum infections. When applied at the concentration range from 0.001 to 0.1% (wt/vol), chitosan did not influence the population growth of C. laurentii in vivo, whereas it markedly repressed the yeast growth as its concentrations were increased up to 0.25% (wt/vol) or higher. Moreover, combination of chitosan and C. laurentii resulted in a synergistic inhibition of the blue mold rot, being the most effective at the optimal concentration of 0.1% of chitosan with the lowest viscosity (12 cP). The possible mode of action of the combination of chitosan and C. laurentii was discussed.