【作者】 张鹏；

【导师】 孟宪军； 张平；

【作者基本信息】 沈阳农业大学 ， 食品科学， 2011， 博士

【摘要】 磨盘柿原产于我国,属涩柿品系中的优良主栽品种之一,采后果实脱涩、保脆及防褐变是其贮藏保鲜中急于解决的技术瓶颈。国内外对上述问题均开展了相关研究,但多集中于单一化技术性应用或生理生化方面的研究,涉及了成熟度、温度、高CO2、乙烯、相关酶与底物等指标的影响,但这些指标间的内在联系,以及它们之间的交互作用,仍缺乏系统的全面阐述,对磨盘柿果实涩度、脆度及褐变有效的调控机理及其无损检测技术更鲜有研究。本研究确定了磨盘柿采后涩味脱除的关键技术参数,在此基础上,开展了C02、真空包装、液浸、1-MCP处理、普通冷藏、减压贮藏、冰温贮藏及其配套集成技术对果实涩度、脆度、褐变的调控效应及相关机理的研究,着重探讨了近红外漫反射光谱建立磨盘柿果涩度(可溶性单宁)、脆度与品质(硬度、TSS)和褐变指标(果皮颜色和果肉浊度)的近红外光谱无损模型与精度预测,以及近红外漫反射光谱无损预测磨盘柿内部品质的可行性。得出结论如下：1.C02全脱涩条件：环境温度为25℃、CO2浓度为90%、脱涩时间24 h；C02二段法脱涩条件：环境温度为18-20℃、网套包装、90% C02脱涩24 h后再放置24 h；真空包装脱涩条件：环境温度为18-20℃、真空度0.08 MPa、脱涩时间10d；八成熟真空包装果实常温下脱涩时间为14d,而冷搀藏下脱涩时间为45 d,脱涩效果好,且果实易于转色；冰温下,用含有2%NaCl溶液贮藏,在贮藏45 d时可以完全脱涩。2.常温货架和冷藏期间,1-MCP处理均有效的延缓了柿果硬度和可溶性单宁的下降,抑制了果实的呼吸强度和乙烯生成量的增加,并推迟了呼吸高峰和乙烯高峰出现的时间,有效抑制贮藏后期果实MDA和膜相对电导率的增加,延缓了果实成熟衰老进程；抑制了PG活性、Cx活性、淀粉酶活性的增加,延缓果实软化进程；但对果实PE活性没有抑制作用；导致果实软化的影响因素次序为：PG>Cx>淀粉酶>PE。3.减压贮藏、冰温贮藏、1-MCP结合冰温贮藏均抑制果实硬度和Vc的下降,延缓TSS的升高、TA的下降,推迟果实呼吸高峰和乙烯高峰的到来的时间,延缓内源乙烯生成量；抑制了贮藏后期果实MDA和膜相对电导率的增加、总酚含量的下降和PPO活性的增加、贮藏前期POD活性,保持了较高的SOD活性；其中与普通冷藏相比,减压冷藏果实保鲜期延长了30 d左右,冰温贮藏延长了45 d以上,1-MCP结合冰温贮藏延长了60 d以上。4.可溶性单宁采用MPLS、二阶导处理和去散射处理建立的定标模型,Rcv为0.8754,RMSECV为0.0936,模型预测的Rp2为0.825,RMSEP为0.1116,RPD为2.33；硬度采用MPLS、一阶导处理和无散射处理建立的定标模型,Rcv为0.9507, RMSECV为1.1421,模型预测的Rp2为0.952,RMSEP为1.3303,RPD为4.55；TSS采用MPLS、一阶导处理和去散射处理建立的定标模型,Rcv为0.8420,RMSECV为0.3857,模型预测的Rp2为0.836,RMSEP为0.3636,RPD为3.30。表明可见/近红外光谱可以作为快速无损的检测技术来测量磨盘柿内部指标可溶性单宁、硬度和TSS。三个指标的综合模型MPLS、一阶导处理和无散射处理建立定标模型并进行模型预测,综合模型精度均有所下降,只能粗略的进行定量分析,故模型精度有待进一步提高。5.L*采用MPLS、原始光谱和无散射处理建立定标模型的Rcv为0.9774,RMSECV为0.8268,模型预测的Rp2为0.959,RMSEP为1.1120,RPD为5.09；a*采用MPLS、一阶导处理和无散射处理建立定标模型的Rcv为0.9896,RMSECV为0.5503,模型预测的Rp2为0.985, RMSEP为0.5859,RPD为11.38；b*采用MPLS、原始光谱和无散射处理建立定标模型的Rcv为0.9788,RMSECV为1.3775,模型预测的Rp2为0.968,RMSEP为1.4177,RPD为7.92。每个模型都具有很好的预测结果。而三个指标的综合模型采用MPLS、一阶导处理和无散射处理建立定标模型并进行模型预测,综合模型精度均有所下降,但L*、a*、b‘的RMSECV和RMSEP均>0.9,且RPD>3.0,模型具有较好的适用性。果肉浊度模型采用PLS、一阶导处理和无散射处理建立的定标模型,Rcv为0.7766,RMSECV为0.1143,模型预测的Rp2为0.757,RMSEP为0.1079,RPD为2.22,只可以进行粗略的定量分析,因此,可见／近红外漫反射技术对磨盘柿果肉浊度的快速无损检测具有一定的可行性,但模型精度有待进一步提高。更多还原

【Abstract】 Mopan persimmon (Disopyos Kaki L.) originated in our country is one of the major varieties of astringent persimmon lines. De-astringency, crispness-keeping and browning-preventing have been anxious to resolve posthavest storage technique bottleneck. Although there are many reports about above questions, and yet most opinions fastened on simplification technique or physiological researches, such as maturity, temperature, high CO2, ethylene, correlation emzyme and substrate, and etc. Presently, the relationship between these indexes and their interactions have not been compressively elucidated yet, and effective regulation mechanism and its nondestructive measurement technique of fruit de-astringency, crispness-keeping and browning have studied rarely.The key technique parameter of Mopan persimmon posthavest de-astringecy was ascertained. In this paper, regulation effect and correlation mechanism of CO2, vaccum packaging, liquid storage.1-MCP treatment, common cold storage, hypobaric storage, controlled freezing point storage and integration technique on fruit were studied, and nondestructive models and precision forecast of de-astringency(soluble tannin content), crispness-keeping and quality(firmness and TSS), and browning indexes(peel color and flesh turbidity) in Mopan persimmon by near-infrared diffuse reflectance spectra, and feasibility of nondestructive measurement these indexes were discussed. Research results were as follows:1. The CO2 whole de-astringent condition was ambient temperature of 25℃, CO2 concentration of 90% and de-astringent time of 24 h. The CO2 de-astringent of two stage method was ambient temperature from 18 to 20℃, packaging of plastic net and placement 24 h after 90% CO2 de-astringent 24 h. The vaccum packaging de-astringent condition was ambient temperature from 18 to 20℃, vaccum degree of 0.08 MPa and de-astringent time of 10 d. The de-astringent time of eight degree ripeness fruit with vaccum packaging was 14 d under ambient temperature, which was 45 d under low temperature and turned color easily. The de-astringent time of fruit with 2% NaCl liquid stroge was 45 d under contolled freezing point storage.2.1-MCP treatment postponed the decrease of fruit firmness and soluble tannin effectively, controlled the increase of fruit respiration intensity and ethylene production, delayed the peak time of fruit respiration intensity and ethylene production, restrained rise of later storage fruit MDA and membrance relative conductance, deferred fruit ripe and senescence process, and improved increase of PG, Cx and amylase activity, deferred fruit softening process, but has no effect on PE activity during ambient and low temperature. Fruit softening influence factors from big to small was PG, Cx, amylase, PE. 3. Hypobaric cold storage, contolled freezing point storage and 1-MCP combined with contolled freezing point storage could control the decrease of fruit firmness, Vc and TA content, delayed the hoist of TSS, delayed the increase of respiration intensity and ethylene production, restrained later storge MDA. membrance relative conductance and PPO activity, controlled the decline of total phenol, SOD activity and former storage POD activity. Mopan persimmon storage time with hypobaric cold storage extended about 30 d, fruit storage time with contolled freezing point storage extended 45 d upwards, fruit storage time with 1-MCP combined with contolled freezing point storage extended 60 d upwards.4. Soluble tannin model used MPLS, second derivative and DET treatment to establish calibration model and to predict, and Rcv was 0.8754, RMSECV was 0.0936, Rp2 was 0.825, RMSEP was 0.1116, RPD was 2.33. Firmness model used MPLS, first derivative and None treatment to creat calibration model and to predict, and Rcv was 0.9507, RMSECV was 1.1421. Rp2 was 0.952, RMSEP was 1.3303, RPD was 4.55. TSS model used MPLS, first derivative and DET treatment to creat calibration model and to predict, and Rcv was 0.8420, RMSECV was 0.3857, Rp2 was 0.836, RMSEP was 0.3636, RPD was 3.30. Therefore, the preliminary research on the built models indicated that nondestructive measurement of the fruit soluble tannin content, firmness and TSS using VIS/NIR spectroscopy technique was feasible.Three indexes comprehensive model used MPLS, first derivative and None treatment to establish calibration model and to predict, but the model precision declined to some extent, could only proceed quantitative analysis roughly, the precision of the models could be improved further.5. L model used MPLS, original spectra and None treatment to establish calibration model and to predict, and Rcv was 0.9774, RMSECV was 0.8268, Rp2 was 0.959, RMSEP was 1.1120, RPD was 5.09. a* model used MPLS, first derivative and None treatment to establish calibration model and to predict, and Rcv was 0.9896, RMSECV was 0.5503, Rp2 was 0.985, RMSEP was 0.5859. RPD was 11.38. b* model used MPLS, original spectra and None treatment to establish calibration model and to predict, and Rcv was 0.9788, RMSECV was 1.3775, Rp2 was 0.968, RMSEP was 1.4177, RPD was 7.92. Three models had good predicted result. Three indexes comprehensive model used MPLS, first derivative and None treatment to establish calibration model and to predict, but the model precision declined to some extent, but its RMSECV and RMSEP was above 0.9, RPD was above 3.0, this model had good applicability. Flesh turbidity model used PLS, original spectra and None treatment to establish calibration model and to predict, and Rcv was 0.7766, RMSECV was 0.1143, Rp2 was 0.757, RMSEP was 0.1079, RPD was 2.22. The model could only accomplish quantitative analysis roughly. Therefore, the preliminary research on the built models indicated that nondestructive measurement of the flesh turbidity VIS/NIR spectroscopy technique was feasible, but the precision of the models could be improved further.更多还原