【作者】 钱金；

【导师】 郁志芳；

【作者基本信息】 南京农业大学 ， 食品工程， 2007， 硕士

【摘要】 本研究采用南京地产马兰头（Kalimeris indica（L.）Sch.-Bip.）,新鲜马兰头采摘后于室温下晾除表面水分,按200g/袋装入家用保鲜袋,并按挽口和敞口两种方式包装后分别置于0℃、10℃、常温环境下贮藏,每处理重复三次。贮藏期间每5天测定马兰头组织的相关生理生化指标,研究其贮藏过程中品质和生理特性的变化;鉴定分析了马兰头酶促褐变底物,并研究了褐变关键酶PPO和POD的特性。结果如下:1、常温下贮藏5d敞口、挽口包装的马兰头失重率分别为24%和0.5%,黄化腐烂率分别为29.43%和28.99%,均失去商品价值;10℃贮藏15d时,敞口、挽口包装马兰头的失重率分别为70%和2.5%,黄花腐烂率分别为40.8%和29.5%,也失去商品价值;0℃贮藏20d时两种包装的马兰头几乎没有黄化发生,敞口、挽口失重率分别为15%和2.5%;马兰头0℃下贮藏20d无冷害症状发生,0℃是其适宜的贮藏温度。2、常温5天后,敞口、挽口包装的马兰头还原糖的含量分别降低了34.4%、32.4%,Vc含量仅为贮前含量的1/4左右;10℃贮藏15天时还原糖含量的减少也都超过了50%,Vc含量损失了68.63%;0℃低温贮藏环境中贮藏20天后,马兰头还原糖含量约为贮前的1/2,Vc在贮藏前期含量保留率较高,后期下降速率加快,至20天时,保留率不到40%。3、贮藏期间,不同贮藏温度环境下的马兰头叶绿素含量均呈下降趋势,但下降幅度不同,常温和10℃下叶绿素含量减少速率一直较快,而0℃在贮藏前5天降低幅度较大,损失了34.3%,随后则起伏平稳;各个处理的马兰头纤维素含量在贮藏期间不断上升,贮藏温度越高,纤维素含量上升幅度越快,且敞口包装更有利于纤维素的合成;相关性分析表明:叶绿素含量的减少与黄化的发生显著相关;纤维素含量的增加与水分损失极显著正相关（r=0.8605,p＜0.01）。4、马兰头的呼吸作用旺盛,采后达132.15±9.15 CO₂mg.Kg^-1.h^-1;在贮藏期间,各个温度环境中马兰头呼吸强度贮藏5天均呈峰型增加,随后下降,贮藏后期又有所增加;0℃低温环境下的马兰头仍然保持较低水平的呼吸强度,只有较小幅度的起伏,有利于马兰头品质的保持。5、马兰头贮藏期间各处理的O₂^·-含量均呈不断增加趋势,但增加幅度不同;常温贮藏期间马兰头O₂^·-增加最快,5d后敞口包装O₂^·-含量为152.64nmol.mg-1.FW,达到贮前水平的3倍之多;10℃下,O₂^·-含量上升幅度也较快,15天时两种包装均比贮前水平增加了2.5倍左右;0℃可显著降低马兰头O₂^·-的生成,尤以挽口包装明显。6、贮藏温度和包装方式对马兰头MDA和电导率的影响较为相似,表现为不同处理的马兰头在贮藏期间MDA含量和电导率均呈不断增加趋势,且贮藏温度愈低、增加幅度愈小。0℃能显著减缓马兰头MDA含量和电导率的上升趋势,挽口包装效果尤为显著。7、贮藏期间各个处理马兰头纤维素酶活性整体呈增加趋势;超氧化物歧化酶（SOD）活性的变化呈先下降、后上升的趋势;苯丙氨酸解氨酶（PAL）活性起伏较大;多酚氧化酶（PPO）活性极弱且贮藏期间整体呈先上升后下降的趋势;过氧化物酶（POD）活力非常高,是马兰头生理生化作用的关键酶,在贮藏期间活力整体呈下降趋势,但仍保留很高活力。不同贮藏温度和包装方式对于马兰头纤维素酶活性、SOD、PAL、PPO、POD活力有显著影响。8、新鲜马兰头组织中TP和FP含量分别为5.96和2.77ug.g^-1.FW,FP占TP的比例46.5%;贮藏期间各处理马兰头组织中TP和FP含量整体呈减少趋势。马兰头组织中酚类物质在经过薄层层析、紫外扫描、HPLC初步鉴定后,结果显示马兰头组织中的主要酚类物质是儿茶酚。9、马兰头PPO最适作用pH为5.4,最适作用底物是表儿茶酚;POD酶最适作用pH为5.0,最适作用底物为咖啡酸。10、马兰头在0℃和挽口的条件下,贮藏时间可达到20d以上。更多还原

【Abstract】 The fresh Kalimeris indica（L.） Ch.-Bip.produced in Nanjing,after removing the superficial moisture,was packed in home use plastic bags loosely closed or openly weighed 200g per bag,and then separately stored at 0℃,10℃,and the normal temperature environment.Each treatment was replicated for three times.The related physiological and qualitative indices were determined every 5 days.The main type of phenols,PPO and POD characteristics of Kalimeris indica（L.） Ch.-Bip.were analyzed.The result is showed as follows:1.Under rooml temperature after 5 days,the weight loss rate of loosely closed and openly packed Kalimeris indica（L.） Ch.-Bip.was 24%and 0.5%,respectively,and the etiolution and decay rate was 29.43%and 28.99%,respectively.Both caused the loss of produce value.Stored at 10℃for 15 days,the weight loss rate of loosely closed and openly packed Kalimeris indica（L.） Ch.-Bip.was 70%and 2.5%respectively,the rate of etiolution and decay 40.8%and 29.5%respectively;Stored at 0℃,nearly no etiolution and decay occurred in the two packages,the weight loss was 15%and 2.5%,respectively after 20 day storage.There was no chilling symptom observed in the tissue of Kalimeris indica （L.） Ch.-Bip.stored at 0℃,suggesting 0℃is suitable for storing Kalimeris indica（L.） Ch. -Bip..2.Under the normal temperature after 5 days,reducing sugar in loosely closed and openly packed Kalimeris indica（L.） Ch.-Bip.reduced almost the same（by 34.4%,32.4%, respectively）;and the Vc was only 1/4 of the content before storing;At 10℃for 15 days, reducing sugar in both packages lost more than 50%,and the Vc lost about 68.63%;At 0℃, there were only a half reducing sugar lost after 20 day storage,and Vc maintained about 40%original content after 20 day storage.3.During storage period,chlorophyll content of Kalimeris indica（L.） Ch.-Bip.stored under the different temperature all dropped,but the extent was different.The chlorophyll dropped quickly under normal temperature and 10℃during storage period;but the reduction rate at 0℃was fast at the first 5 days,lost approximately 34.3%,and showed stable afterwards;The cellulose content continuously increased during the storage period at all 3 storage temperature,the higher the temperature,the faster the cellulose increase,and the open package could slowdown the increase.The relevant analysis indicated that there was remarkablely correlation between chlorophyll content reduction and etiolution occurrence,and the cellulose content increase was extremely related to the moisture loss （r=0.8605,p＜0.01）.4.The respiratory rate of Kalimeris indica（L.） Ch.-Bip.was very high after harvest and could reach 132.15±9.15 CO₂mg.Kg^-1.h^-1.During initial 5 day storage,the respiratory rate of all treated Kalimeris indica（L.） Ch.-Bip.was increased and then decreased,and with the increase of decay and weight loss,the respiratort rate increased again.Compared the respiratory difference at 3 storage temperature,the respiratory rate of Kalimeris indica （L.） Ch.-Bip.maintained a lower level and only had a smaller fluctuation at 0℃,indicating 0℃was better to maintain the quality ofKalimeris indica（L.） Ch.-Bip..5.The O₂^·-content of all treated Kalimeris indica（L.） Ch.-Bip.continuously increased,but the extents were different.At the room temperature,the O₂^·-content of Kalimeris indica（L.） Ch.-Bip.increased quickly,after 5 days the O₂^·-content of open packs was high to 152.64nmol.mg-l.FW,3 times of the level before storing;the O₂^·-content rose less quickly at 10℃,for 15 days two kinds of packs even arrived about 3.5 times of the level before storing;low temperature may remarkably reduce the production of O₂^·-,especially the loosely closed pack was even obvious;6.The influence of storage temperature and the packing on MDA and conductivity was similar,both increased with the extension of storage period.Results also showed that the lower the temperature,the less MDA content and smaller conductivity increased; Kalimeris indica（L.） Ch.-Bip.treated with loosely closed packs at 0℃could remarkably slow down the escalation trend of MDA content and the conductivity.7.The activity of cellulase in Kalimeris indica（L.） Ch.-Bip.of all treatments increased.SOD activities dropped at first,then rose.PAL activities changed irregularly,and had a big fluctuation.Kalimeris indica（L.） Ch.-Bip.had very weak PPO activity rose at first,then dropped during storage period.POD activity of Kalimeris indica（L.） Ch.-Bip. was very high,and still dropped during storage but still retained a high level.The storage temperature and the packing significantly influenced cellulase,SOD,PAL,PPO and POD activities.8.The TP and FP content in fresh Kalimeris indica（L.） Ch.-Bip.tissue was 5.96 and 2.77ug.g^-1.FW,respectively,and the ratio of FP to TP was 46.5%.During storage period, the TP and FP content of all the treatment declined.The main phenol in the tissue of Kalimeris indica（L.） Ch.-Bip.was catechol.9.The optimal pH of PPO in the tissue ofKalimeris indica（L.） Ch.-Bip.is pH5.4,and the most suitable functional substrate is catechol;the optimal pH of POD is pH5.4,and the most suitable functional substrate is caffeic acid.10.The storage duration ofKalimeris indica（L.） Ch.-Bip.which was loosely packed and stored at 0^C could be as long as 20 days.更多还原