复载纳他霉素的壳聚糖/玉米醇溶蛋白可食性涂膜对芒果低温保鲜效果的研究

为探究不同纳他霉素添加量（0.05、0.1、0.2 g/kg）对壳聚糖/玉米醇溶蛋白可食性复合涂膜保鲜芒果（N₁、N₂、N₃）效果的影响,以壳聚糖/玉米醇溶蛋白复合涂膜处理为阳性对照（CZ）,以清水处理为空白对照（CK）,研究芒果在低温（13℃）贮藏30 d过程中转黄率、病情指数、果肉色泽特征、生理生化、品质变化及抗氧化能力。结果表明：CK组贮藏期仅为24 d,涂膜处理可至少将芒果贮藏期延长6 d;纳他霉素涂膜组推迟了芒果呼吸高峰的出现,N₃组的呼吸峰值最低;与CK组相比,N₃组在24 d的转黄率和病情指数分别降低了45.83%和44.17%;N₃组显著抑制了自由水分、果实质量和硬度的下降,保持了可溶性固形物、可滴定酸和维生素C等营养物质含量;同时,涂膜组的POD和SOD含量均显著低于CK组,果肉总色差和相对电导率上升得到了抑制,说明复合涂膜处理有效延缓了芒果衰老进程,保持了更好的果实新鲜度。综上,添加纳他霉素的壳聚糖/玉米醇溶蛋白可食性复合涂膜可显著提升对芒果的保鲜效果,添加量为0.2 g/kg的纳他霉素复合涂膜效果更佳。纳他霉素复合涂膜在水果保鲜的应用中具有良好的前景。     

肉桂精油复合壳聚糖涂膜对采后番木瓜炭疽病的防治效果及作用机制分析

番木瓜是我国著名的热带、亚热带水果之一,但番木瓜属于呼吸跃变型果实,采后不耐贮运,其中由炭疽病引起的腐烂损失最为严重。因此,如何防治番木瓜采后炭疽病,降低番木瓜腐烂损失,延长贮藏保鲜期,成了制约番木瓜产业健康发展的瓶颈问题。本文以‘大青’番木瓜为试验材料,以绿色环保的肉桂精油-壳聚糖复合保鲜液为处理手段,研究其对采后番木瓜炭疽病的防治效果及作用机制,为我国番木瓜采后贮运保鲜产业发展提供理论依据和应用参考。分别用0.5%壳聚糖、0.5%壳聚糖+0.3%肉桂精油、0.5%壳聚糖+0.5%肉桂精油、0.5%壳聚糖+0.7%肉桂精油溶液对采后番木瓜果实进行喷雾处理,清水处理作为对照,处理后的番木瓜分为2组,其中一组处理后置于25℃下恒温贮藏,定期测定果实病情指数;另一组处理后置于25℃下恒温贮藏24 h后,在果面刺伤接种番木瓜炭疽菌,定期调查果实病斑直径,并对果皮进行取样,测定不同处理果实的抗病相关物质含量和抗病相关酶活性的变化情况。番木瓜炭疽菌的离体抑菌实验采用含药PDA平板抑菌法进行测定。研究结果表明:0.5%壳聚糖+0.3%肉桂精油处理对番木瓜炭疽病的防治效果最好,复合处理可完全抑制离体番木瓜炭疽菌的生长和产孢,复合处理显著降低了番木瓜果实的病斑直径,提高了抗病相关物质木质素、总酚(TP)和过氧化氢(H₂O₂)的含量,提高了抗病相关酶苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和β-1,3葡聚糖酶(β-1,3-GA)的活性,但对几丁质酶(CHI)活性影响不大。由此可见,肉桂精油复合壳聚糖涂膜对番木瓜炭疽菌有较好的防控效果,一方面是由于复合处理抑制了番木瓜炭疽菌的生长,另一方面是复合处理诱导番木瓜果实提高了抗病性。因此,适宜浓度的肉桂精油复合壳聚糖涂膜处理为防控番木瓜采后炭疽病提供了一种绿色新途径。     

肉桂精油复合壳聚糖涂膜对采后番木瓜炭疽病的防治效果及作用机制分析

番木瓜是我国著名的热带、亚热带水果之一,但番木瓜属于呼吸跃变型果实,采后不耐贮运,其中由炭疽病引起的腐烂损失最为严重。因此,如何防治番木瓜采后炭疽病,降低番木瓜腐烂损失,延长贮藏保鲜期,成了制约番木瓜产业健康发展的瓶颈问题。本文以‘大青’番木瓜为试验材料,以绿色环保的肉桂精油-壳聚糖复合保鲜液为处理手段,研究其对采后番木瓜炭疽病的防治效果及作用机制,为我国番木瓜采后贮运保鲜产业发展提供理论依据和应用参考。分别用0.5%壳聚糖、0.5%壳聚糖+0.3%肉桂精油、0.5%壳聚糖+0.5%肉桂精油、0.5%壳聚糖+0.7%肉桂精油溶液对采后番木瓜果实进行喷雾处理,清水处理作为对照,处理后的番木瓜分为2组,其中一组处理后置于25℃下恒温贮藏,定期测定果实病情指数;另一组处理后置于25℃下恒温贮藏24 h后,在果面刺伤接种番木瓜炭疽菌,定期调查果实病斑直径,并对果皮进行取样,测定不同处理果实的抗病相关物质含量和抗病相关酶活性的变化情况。番木瓜炭疽菌的离体抑菌实验采用含药PDA平板抑菌法进行测定。研究结果表明:0.5%壳聚糖+0.3%肉桂精油处理对番木瓜炭疽病的防治效果最好,复合处理可完全抑制离体番木瓜炭疽菌的生长和产孢,复合处理显著降低了番木瓜果实的病斑直径,提高了抗病相关物质木质素、总酚(TP)和过氧化氢(H₂O₂)的含量,提高了抗病相关酶苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和β-1,3葡聚糖酶(β-1,3-GA)的活性,但对几丁质酶(CHI)活性影响不大。由此可见,肉桂精油复合壳聚糖涂膜对番木瓜炭疽菌有较好的防控效果,一方面是由于复合处理抑制了番木瓜炭疽菌的生长,另一方面是复合处理诱导番木瓜果实提高了抗病性。因此,适宜浓度的肉桂精油复合壳聚糖涂膜处理为防控番木瓜采后炭疽病提供了一种绿色新途径。     

壳聚糖对金线莲保鲜作用研究

以新鲜金线莲为试验材料,探讨不同质量分数(0.5%、1.0%、1.5%)壳聚糖不同处理(整株浸、根浸)对金线莲常温贮藏植株品质及采后生理生化变化的影响。结果表明:与对照组相比,采用根部浸渍的壳聚糖处理可以有效降低金线莲植株贮藏过程中的腐烂率和失水率,延缓可溶性固形物的下降,维持相对电导率较平缓的上升,说明壳聚糖处理对金线莲贮藏品质的保持具有较好的效果,可有效地延长金线莲的贮藏期,其中,以质量分数浓度为1.0%的壳聚糖处理效果最好。     

不同处理对桃形李采后病原菌的防治效果

桃形李采后极易发生病害,难以保鲜,为了控制桃形李采后病害的发生,通过对分离到的病原菌扩展青霉菌株(Penicillium expansum,TXL-01)进行形态学观察和对其它水果致病性试验,分别用硝普钠、葡萄籽提取物和NaHCO_3在PDA培养基上进行抑菌实验。结果表明:形态学观察发现致病菌菌丝有分枝和横隔膜,具帚形孢子囊,能产生大小不同的2种类型孢子;对多种水果侵染后均能致病,说明致病菌对宿主要求专一性不高;硝普钠和葡萄籽提取物只能在前3 d抑制病原菌的生长,但是在第4天以后与对照无明显差异;NaHCO_3浓度为0.10%和0.15%时,培养到第6天时能显著抑制病原菌生长;当NaHCO_3为0.2%时,培养到第12天时内还能抑制病原菌生长;再分别以0.10%、0.15%、0.20%NaHCO_3和0.20%NaHCO_3+1.0%壳聚糖(Chitosan)复合处理桃形李采后果实,发现0.20%NaHCO_3处理虽然也能减少果实腐烂率,但结合1.0%Chitosan涂膜处理对果实保鲜效果更好,可以显著抑制致病菌的发生,降低果实发病率,说明NaHCO_3和Chitosan复合处理可以应用于桃形李的采后保鲜。     

柠檬酸处理对鲜切粉葛褐化保鲜效果研究

研究柠檬酸处理对鲜切粉葛护色效果的影响,将鲜切粉葛分别放入0.5%、1.0%、1.5%柠檬酸溶液浸泡15 min后沥干,放置塑料托盘中,用聚乙烯保鲜膜包装后置于5℃恒温恒湿箱中贮藏,定期取样测定相关生理指标。结果表明,不同浓度柠檬酸处理能有效减轻鲜切粉葛的褐变程度,以0.5%柠檬酸处理效果较好,能显著降低PAL活性和总酚含量,抑制PPO和POD活性,减少丙二醛积累,保持较低的LOX活性,从而延缓鲜切粉葛的褐变,同时提高了总黄酮含量,减少淀粉、可溶性蛋白等营养物质的损失,有助于保持粉葛的良好品质。适宜浓度柠檬酸预处理可显著减轻鲜切粉葛褐变程度,维持较好的营养品质。研究结果为鲜切粉葛护色工艺提供参考。     

酸性电解水结合复合膜对橘柚保鲜效果的研究

为了防止橘柚采后枯水腐烂,采用酸性电解水浸果处理,并结合海藻酸钠、羧甲基纤维素钠、茶多酚、抗坏血酸配制成的复合保鲜剂进行涂膜处理后,将橘柚果实置于温度为 (8±1)℃、湿度为75%~80%的条件下存放120 d,以好果率、失重率、细胞膜透性、可滴定酸度、可溶性固形物以及类胡萝卜素为指标进行保鲜效果的评价,通过正交试验确定最佳保鲜方法。本研究所用的复合膜是多孔网络结构的薄膜,空隙小而细腻、均匀分散,复合膜处理后的果皮表面平整光滑,断面结构致密,在果实表面形成屏障。结果表明：酸性电解水处理能有效控制橘柚果实采后病害的发生,复合膜处理可以较好地控制橘柚的腐烂和失水现象,延缓果实衰老,有效保持可滴定酸和可溶性固形物的含量,还能提高果皮色泽;正交试验优化得出最优的保鲜方法,以有效氯含量为30 mg/L的酸性电解水浸果15 min,并联合海藻酸钠0.5%、羧甲基纤维素钠0.5%、茶多酚2.0%、抗坏血酸1.0%配比组合下的复合保鲜剂涂膜20 min。因此认为,酸性电解水结合复合膜处理能提高采后橘柚的品质、延长果实保鲜期。     

贵州山地芒果复合保鲜剂的筛选及保鲜效应分析

为研究复合保鲜剂对山地芒果的保鲜效应,选用赤霉素、壳聚糖和氯化钙3种保鲜剂对贵州山地芒果贮藏保鲜进行试验分析。以“桂热芒10号”为材料,综合发病指数、转黄率两个表观指标分析得出：单一保鲜剂处理的过程中,赤霉素浓度为300 mg/L,壳聚糖浓度为1.0%,芒果果实贮藏时间长,效果佳;复合保鲜剂处理中配制300 mg/L的赤霉素、0.75%壳聚糖和3%氯化钙组合溶液,芒果在常温贮藏下表现良好。并将这3种处理果实的呼吸强度、可溶性固形物和Vc含量进行比较表明：复合保鲜剂处理后,果实的可溶性固形物含量维持时间长、能有效延缓果实呼吸、维持Vc含量的降低。证实了芒果通过复合保鲜剂(300 mg/L赤霉素+0.75%壳聚糖+3%氯化钙)处理能有效增强果实在常温条件下的耐贮藏能力。     

D-异抗坏血酸钠对茄子鲜切切片的保鲜效果研究

[目的]研究不同浓度的D-异抗坏血酸钠对茄子鲜切切片的保鲜效果。[方法]以茄子鲜切切片为材料,研究0、0.5%、1.0%、1.5%、2.0%浓度的D-异抗坏血酸钠溶液对茄子切片的保鲜效果的影响。[结果]1.0%D-异抗坏血酸钠溶液处理效果较好,能够有效降低茄子切片褐化度、PPO活性和MDA含量,促进POD酶活性。[结论]该研究筛选出了茄子切片最佳保鲜浓度,为茄子鲜切保鲜提供了理论依据。     

壳聚糖处理对采后建阳桔柚果实品质和贮藏特性的影响

探讨不同浓度壳聚糖处理对采后建阳桔柚果实在(10±1)℃下贮藏的生理特性、营养品质和贮藏特性的影响。结果表明：与对照果实相比,壳聚糖处理能降低建阳桔柚果实的呼吸强度,延缓果皮细胞膜透性的升高,抑制果实表面色调角h°值下降,果肉能保持较高的可溶性固形物、可滴定酸度、总糖、维生素C和类胡萝卜素含量,减少建阳桔柚果实失重和腐烂,保持较高商品率。其中以稀释500倍壳聚糖处理的保鲜效果最佳,果实商品率一直保持在95%以上,感病指数控制在0.1以下,而且果肉基本无汁胞枯水现象,贮藏后期果实的失重率可控制在5%以内。因此认为,稀释500倍壳聚糖处理是保持采后建阳桔柚品质、延长其保鲜期的有效方式。     

杨桃草酸的分布及其果实草酸含量变化的研究

采用离子色谱法对新加坡甜杨桃和广州本地酸杨桃的叶、叶柄、根和不同发育时期的果实及其不同部位进行了草酸含量的测定,同时对不同施肥处理、热水处理的甜杨桃果实分别进行了草酸含量的测定。结果表明,杨桃果实草酸含量先迅速上升,然后逐渐下降,谢花80d左右处于低峰值;杨桃叶片的草酸含量最高,果肉的草酸含量最低;施有机肥可有效降低甜杨桃果实水溶性草酸含量;热水处理3 min可降低果肉水溶性草酸含量42%以上。     

壳聚糖包衣对水分胁迫下玉米种子萌发和幼苗生长的影响

壳聚糖(Chitosan,CS)是一种天然高分子物质,通过壳聚糖应用于种子包衣,研究对水分胁迫条件下玉米种子萌发和幼苗生长的影响。结果表明,壳聚糖包衣处理明显提高玉米种子的发芽率、发芽指数及活力指数,中度水分胁迫下发芽率比对照高6.9%,达极显著差异;玉米幼苗变高,茎粗和根长增加,根冠比极显著提高;降低玉米幼苗叶片的脯氨酸和丙二醛含量,提高叶绿素含量以及超氧化物歧化酶活性,有利于增强玉米幼苗的抗旱能力。     

Application of Soluble Chitosan in vitro and in the Greenhouse to Increase Yield and Seed Quality of Potato Minitubers

The aim of this work was to investigate whether the application of soluble chitosan in potato micropropagation can improve microplant quality in vitro, help acclimatisation ex vitro, and increase yield and seed quality of minitubers. Potato cv. Désirée microplants were treated in vitro with soluble chitosan added to the semisolid tissue culture medium in different concentrations. Microplants were subsequently transferred to the greenhouse and sprayed with chitosan solutions or remained unsprayed. Untreated microplants were also established ex vitro and sprayed with chitosan, or left unsprayed as a control. Morphological and physiological parameters of plant growth were assessed in vitro and ex vitro. Plantlet quality was evaluated using a ranking system. Minitubers derived from greenhouse plantlets were planted in the field in subtropical conditions, and growth and yield parameters evaluated. The chitosan concentration most beneficial to the in vitro growth of microplants varied between years. In treatments with the best in vitro growth, minituber number and yield in the greenhouse was also increased. Foliar chitosan application at the acclimatisation phase stabilised the effect of in vitro treatment on yield parameters. The seed quality of minitubers derived from chitosan treatments in vitro alone and in combination with foliar treatment at acclimatisation was improved, giving rise to field plants with increased tuber numbers and yields. The combination of chitosan in vitro and foliar application during the acclimatisation phase ex vitro had a greater effect on minituber seed quality than the concentration applied in vitro.     

壳聚糖在茶树上的应用效应

采用叶面喷施的方法，对壳聚糖在茶树上的应用效应进行了研究。结果表明，壳聚糖能促进茶树芽叶萌发和生长，提高茶叶产量，增加茶叶中水浸出物和氨基酸含量，降低酚氨比。壳聚糖对茶叶中茶多酚含量有一定的影响，而对咖啡碱影响不大。本试验所设置浓度范围内，150mg／kg是叶面喷施壳聚糖较适宜的浓度。     

香蜜杨桃果实不同部位的可溶性固形物含量分析

2009年7月在三亚市、五指山市香蜜杨桃果园的不同地段、坡向,采集样品果实,测定果实不同部位及全果实的可溶性固形物（TSS）含量。结果表明,同一果实的下端、中部、上端TSS含量差异极显著,中部、全果TSS含量差异不显著。果实下端TSS含量最高,中部次之,上端最低。果棱间、不同果棱中部TSS含量差异圴不显著。对果实中部、全果TSS含量进行线性回归,呈极显著的直线相关。表明果棱中部TSS含量可直接表示全果TSS含量状况。在环境条件和栽培措施等差异下,果实不同部位TSS含量有一致性的显著性差异,果实下端TSS含量最高,中部次之,上端最低。     

Durable antibacterial cotton fabrics with chitosan based quaternary ammonium salt

A water soluble quaternary ammonium chitosan derivative, N-benzyl-N,N-diethyl chitosan quaternary ammonium salt (BDCQA), was prepared for antibacterial finish of cotton textiles. The effects of concentrations of finish agents and treatment time on the add-on ratio of cotton treated BDCQA (BDCQA-cotton) were studied in details. The morphology and thermal property of BDCQA-cotton were characterized by scanning electron microscopy (SEM) and thermagravimetric (TG) analysis. Gram-positive bacterium Staphylococcus aureus (S. aureus) and Bacillus cereus (B. cereus), Gram-negative bacterium Escherichia coli (E. coli) and drug-resistant bacterium Methicillin-resistant Staphylococcus aureus (MRSA), were used to evaluate the antibacterial activity and durability of BDCQA-cotton. The results showed that BDCQA-cotton possessed good antibacterial activity and high durability against broad spectrum bacterium. The preliminary investigation on the antibacterial mechanism was discussed in this work.     

Effects of roasting on barley β-glucan,thermal, textural and pasting properties

Different hulled barley cultivars were subjected to roasting in hot sand (280 °C) and the effects on β-glucan extractability, physico-chemical, thermal and pasting properties were studied. The grain puffed upon roasting and grain hardness and colour difference ΔE were significantly lowered. The roasted barley flour had significantly higher water absorption and water solubility index. The cultivars DWR-28, RD-2503 and PL-172 had the highest total β-glucan content (up to 5.47%). Roasting brought about a decrease in the soluble β-glucan content in all the cultivars and this decrease ranged from 4.9 to 25.3%. The β-glucan extractability was not affected by the roasting process but roasting lowered the ratio of soluble to insoluble β-glucan content by 8.1–41.9%. Roasting significantly affected the pasting and thermal properties of the flours, together with an increase in the cooked starch content that ranged from 28.8 to 43.1%.     

Mechanical properties of semi-interpenetrating polymer network hydrogels based on poly(2-hydroxyethyl methacrylate) copolymer and chitosan

Semi-interpenetrating polymeric network (semi-IPN) hydrogels based on poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(2-hydroxyethyl methacrylate-co-sodium methacrylate) [P(HEMA-co-SMA)], and chitosan with different molecular weights were prepared by crosslinking with ethylene glycol dimethacrylate (EGDMA) and poly(ethylene glycol) diacrylate (PEGDA) and their gelation time, water content, mechanical properties, and morphology were investigated. In consideration of the influence of the molecular weight of chitosan, there is no big difference in the water content, while tensile properties and compressive modulus increased as the molecular weight of chitosan increased. The water content increased and tensile properties and compressive modulus decreased with increasing SMA concentration. Considering the effect of the crosslinking agent, PEGDA had higher water content and lower tensile and compressive moduli than EGDMA. It is suggested that PHEMA/chitosan and P(HEMA-co-SMA)/chitosan semi-IPN hydrogels with different structures and physical properties can be prepared depending on the molecular weight of chitosan, the copolymerization with SMA, and the crosslinking agent type.     

杨桃细菌性褐斑病研究初报

杨桃（Ａｖｅｒｒｈｏａ ｃａｒａｍｂｏｌａ Ｌ．）细菌性褐斑病发病初，小叶出现水渍状小斑点，斑点疹状隆起，随后斑点稍扩大，中央灰白色，边缘不规则，隆起，深褐色，外围有黄色晕圈，数个斑点可汇成斑块，严重时小叶变黄，脱落。通过对病原菌的细菌学性状、致病性、寄主范围以及血清学反应测定，证实杨榉细菌性褐斑病是新病害，病原菌被鉴定为丁香假单胞菌杨桃致病型（Ｐｓｅｕｄｏｍｏｎａｓ ｓｙｒｉｎｇａｅ ＰＶ． ａ     

Effect of irrigation applied at different growth stages and length of irrigation period on quality characters of potato tubers

Summary Potatoes were irrigated at three growth stages: (1) planting-stolon initiation. (2) stolon initiation-tuber bulking, and (3) tuber bulking, when available soil water dropped to 25%, 50% and 75%, bringing it up to field capacity; and irrigation ceased 0, 10 and 20 days before maturity. Significant increases in specific gravity, dry matter, starch content, chip yield and significant decreases in protein content and oil absorption rate of chips were observed due to the frequent irrigation at growth stages 1 and 2. No significant effect on chip colour was attributed to irrigation during the early growth stages. Frequent irrigations at the final growth stage were found to have deleterious effects on specific gravity, dry matter, starch content and chip yield especially when irrigation continued until maturity.