本文關(guān)鍵詞： 石榴 冷害生理 茉莉酸甲酯 病害 殼聚糖　出處：《天津科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：冷害、褐變、腐爛、失水是影響石榴采后保鮮品質(zhì)的重要因素。石榴為低溫敏感性果實(shí),不正常低溫極易導(dǎo)致果實(shí)冷害,影響果實(shí)外觀,加速果皮褐變及果實(shí)腐爛,而影響果實(shí)冷害、病害的因素包括品種、產(chǎn)地、采收期、貯藏條件等。本試驗(yàn)以云南蒙自甜石榴為試材,研究果實(shí)冷害溫度與冷害生理變化,研究MeJA對石榴冷害的調(diào)控作用,通過對果實(shí)采后病原微生物分離、純化、鑒定,確定石榴采后優(yōu)勢致病菌,通過殼聚糖涂膜保鮮,確定殼聚糖對主要致病菌抑制效果及保鮮效果,確定果實(shí)低溫保鮮最佳成熟度、包裝方式、氣調(diào)氣體濃度,指導(dǎo)石榴采后保鮮。通過冷害指數(shù)評估確定果實(shí)在1℃貯藏時(shí),出現(xiàn)明顯冷害癥狀,其中0℃果實(shí)貯藏20d時(shí)表現(xiàn)輕微冷害,130d時(shí),冷害指數(shù)高達(dá)0.54,果皮出現(xiàn)凹陷褐斑,而3℃、4℃貯藏加快果皮褐變和果實(shí)腐爛,確定1℃為果實(shí)冷害溫度,2℃為最適貯藏溫度。低溫冷害破壞了石榴果皮結(jié)構(gòu),果皮表面出現(xiàn)裂痕,表皮粗糙,蠟質(zhì)層減少,失重率增加,破壞果皮細(xì)胞膜結(jié)構(gòu),細(xì)胞膜透性、丙二醛含量增加,0℃貯藏果實(shí)呼吸速率異常升高,貯藏40d時(shí)出現(xiàn)呼吸峰值,之后呼吸強(qiáng)度下降,130d時(shí),細(xì)胞膜透性達(dá)到57.46%,丙二醛含量23.47umol/g. Fw,低溫冷害及相對高溫均加快果皮褐變,褐變與果實(shí)多酚含量、PPO活性密切相關(guān),褐變指數(shù)與多酚含量、PPO活性相關(guān)系數(shù)(R2)分別為0.821、0.729。MeJA提高果實(shí)可溶性蛋白含量,增強(qiáng)果實(shí)抗病性,0.1mmol/L MeJA處理果實(shí)褐變指數(shù)、腐爛率較CK分別降低39.48%,29.61%,有效保持了果實(shí)外觀及營養(yǎng)品質(zhì)。經(jīng)過病原微生物分離、純化、鑒定,確定3種優(yōu)勢致病菌,包括曲霉屬黑曲霉(Aspergillus niger)、青霉屬變紫青霉(Penicillium purpurescens)、葡萄座腔菌屬(BotryosPhaeria),黑曲霉為采后田間病原菌,采后分離率高,貯藏期可引發(fā)果實(shí)軟腐病,變紫青霉主要出現(xiàn)于采后機(jī)械傷部位及冷害病斑部位,病害果實(shí)表面霉變或者出現(xiàn)軟腐,葡萄座腔菌屬主要出現(xiàn)于果實(shí)貯藏后期,病害果實(shí)表面大面積霉變,病斑褐色、水浸狀,是高溫貯藏最主要致病菌。殼聚糖對3種優(yōu)勢致病菌均具有良好的抑制效果,1.0%殼聚糖處理果實(shí)貯藏130d時(shí),腐爛率為4.4%,較CK降低45.68%,失重率為2.24%,果實(shí)外觀良好。石榴為非呼吸躍變果實(shí),低溫貯藏果實(shí)應(yīng)適時(shí)晚采,其中8-9成熟果實(shí)可有效降低果實(shí)采后果皮褐變現(xiàn)象的發(fā)生,采后用0.02mm PE保鮮膜包裝或O2：4%,CO2：5%氣調(diào)處理,可有效保持果實(shí)外觀品質(zhì)。
[Abstract]:Cold damage, browning, decay and water loss are important factors that affect the quality of postharvest pomegranate. Pomegranate is sensitive to low temperature, and abnormal low temperature can easily lead to cold damage and affect the appearance of the fruit. The factors affecting fruit chilling damage include variety, origin, harvest period, storage conditions, etc. In this experiment, Mengzi sweet pomegranate from Yunnan Province was used as the test material. The temperature and physiological changes of fruit chilling injury were studied, and the regulation of MeJA on pomegranate chilling injury was studied. Through the isolation, purification and identification of postharvest pathogenic microorganisms, the dominant pathogen of pomegranate was determined. Through chitosan film preservation, the inhibition effect of chitosan to the main pathogenic bacteria and the preservation effect were determined, and the best maturity, packaging method and atmosphere concentration of fruit preservation at low temperature were determined. To guide the postharvest preservation of pomegranate. Through the evaluation of chilling injury index, the fruit showed obvious chilling injury symptoms when stored at 1 鈩，

本文編號：1475272