【作者】 唐燕；

【导师】 张继澍； 马书尚；

【作者基本信息】 西北农林科技大学 ， 植物学， 2011， 博士

【摘要】 利用日本日置3532-50LCR型LCR电子测试仪和生理生化研究技术,同步测定了桃和猕猴桃电学特性和生理特性的变化规律并比较了二者之间的关系,以期筛选出区分猕猴桃(海沃德、秦美)、桃(秦王、秦光2号桃)果实种类及猕猴桃成熟度和遭受损伤果的敏感电参数和特征电激励频率,筛选出标志果实品质生理指标的敏感电参数,为揭示桃和猕猴桃果实电学特性变化规律积累资料,为利用电特性进行果实无损检测及进一步研制开发相关测试仪器提供一定依据。研究取得的主要结果如下：1.通过LCR电子测试仪对猕猴桃和桃采后所测14个电学参数间的关系的系统分析,果实的14个电参数随频率的变化呈非线性变化。其中复阻抗(Z)、阻抗相角(e)、串联等效电容(Cs)、并联等效电容(Cp)、损耗系数(D)、串联等效阻抗(Rs)、并联等效阻抗(Rp)、电抗(X)随频率变化呈三次函数曲线变化。导纳(Y)、串联等效电感(Ls)、并联等效电感(Lp)、电导(G)、电纳(B)随频率呈指数函数变化。与马海军(2010)在苹果上的研究结果一致,14个电参数可简化为7个电参数(Z、θ、Cp、D、Rp、Rs),为后续研究时选择测试电学参数提供了依据,既简化了手续又节约了时间和成本。2.猕猴桃和桃的logloz和logloLp与loglof均有很好的线性关系,R2均大于0.95。在24个电激励频率下,在100Hz～1.58KHz的电激励频率范围内可用D值、在100Hz-6.31KHz的频率范围内可用0值和Rs值、在100Hz～100KHz的频率范围内,可用G值、在15.8 KHz～100KHz频率范围内可用Z值、在100Hz-158KHz频率范围内可用Cp值区分猕猴桃(海沃德、秦美)和桃(秦王、秦光2号桃)果实。3.通过对室温(25℃)贮藏条件下‘秦光2号’油桃品质参数(硬度,可溶性固形物,酸和含水量)和电参数(Z、Cp、Lp)之间的相关性研究,建立了有效的预测模型(相关系数都达到显著水平),通过验证确定了预测模型的可用性,表明用电参数预测桃品质指标是可行的,有一定的理论意义和实用价值。4.采后‘秦美’猕猴桃在室温(20℃)下,Lp、G和D这三个电参数和生理参数的相关性在所测试的各电激励频率下普遍低,不能标志果实生理指标变化；Z在电激励频率0.1 kHz和2.51MHz、Cp在1MHz和1.58MHz和0在0.1KHz时可作为标志果实生理变化的无损检测敏感电参数。5.‘秦美’猕猴桃随着贮藏时间的延长,硬度、TA都呈下降变化,可溶性固形物呈上升变化,相对电导率在增加,表明细胞膜完整性降低。果实乙烯产生速率的变化和呼吸速率变化都呈单峰曲线变化,且乙烯出峰时间较早。淀粉,纤维素含量的减少与果实硬度的下降呈正相关。‘秦美’猕猴桃软化相关酶活性高峰出现时间有先后,推断先起主要作用的是淀粉酶和PE,之后Cx和PG起主要作用。6.1-MCP处理降低了‘海沃德’猕猴桃果实呼吸速率和乙烯合成速率,同时还延缓了果实硬度、可滴定酸含量、Vc含量的降低幅度和速度,提高了其保护酶SOD、POD、CAT的活性,明显延长了猕猴桃的贮藏寿命。成熟度Ⅱ(晚采收)的‘海沃德’猕猴桃果实较成熟度Ⅰ(适期采收)的果实硬度下降快、乙烯释放量明显高、乙烯释放量高峰时间提前7d,不适长期贮藏。从贮藏7d开始,在特征电激励频率1MHz下可以根据Z值差异、在10KHz频率下可根据Cp值差异对成熟Ⅰ和成熟度Ⅱ的果实加以区分。7.通过对采后‘海沃德’猕猴桃果实进行跌伤(50cm和80 cm)处理发现,机械损伤对猕猴桃果实品质指标中硬度的影响最大,损伤处理加快了果实的呼吸速率,刺激乙烯的大量生成,活性氧的快速增加,LOX酶活性提高,加快了膜脂过氧化的进程,MDA的大量积累,加速了果实衰老、软化的进程。同时,损伤处理能引起电参数发生变化,但不改变果实电参数的总体变化趋势。在100KHz、251KHz、631KHz、和1MHz电激励频率下,损伤能引起果实Z值的降低,果实Lp、D值提高,而对Cp、θ、G的影响小。在100KHz、251KHz、631KHz和1MHz 4个频率下可用电参数Z值、在100KHz或251KHz频率下可用电参数D值对正常果与损伤果加以区分。更多还原

【Abstract】 The variation rules of electrical properties and physiological characteristics of peach and kiwi were synchronously measured by using electronic instrument of Japan 3532-50 LCR and physiological and biochemical technology and the relationship between them compared. The general goals of this study were:1) to distinguish different species of kiwi (Hayward, Qinmei) and different species of peach (Qinwang, Qinguang No 2) by using electrical properties.2) to distinguish different maturity of’Hayward’kiwifruit by using electrical properties.3) to select sensitive electric parameters and characteristic frequency to distinguish the damage of the kiwi.4)to select sensitive electric parameters to quantize quality parameters of fruits.5) to accumulate the data on the change regularity of the kiwi electric properties and provide evidence for further exploiting the new and non-destructive inspecting instrument.The main research results were as follows:1. With the electronic instrument of LCR, the system analysis of the relationship among 14 electrical parameters of kiwifruit and peach was carried out. The electrical parameters include impedance (Z), static capacitance in series equivalent circuit mode (Cs), static capacitance in parallel equivalent circuit mode (Cp), inductance in series equivalent circuit mode (Ls), inductance in parallel equivalent circuit mode (Lp), admittance (Y), impedance phase angle (0), loss coefficient (D), reactance (X), Q factor (Q), effective resistance in series equivalent circuit mode (Rs), effective resistance in parallel equivalent circuit mode (Rp), conductance (G) and susceptance (B). The result showed that 14 electrical parameters is function of frequency;with the frequency shift, Z、θ、Cs、Cp、D、Rs、Rp and X change with cubic function curve; with the frequency shift, Y、Ls、Lp、G、B changes with power function. The same result on apple was found by Ma H J that 7(Z、θ、Cp、Lp、D、Rp、Rs) important parameters can feature the fruit electrical properties. It also provides a basis of electrical test parameters, simplifies the formalities and saves time and cost for the subsequent research.2. log10Z and log10f as well as log10Lp and log10f have a good linear relationship of fruits of kiwi and peach, R2 exceeded 0.95. Kiwi and peach can be distinguished by using value D within the 100Hz～1.58KHz frequency range under 24 electrical frequency. Kiwi and peach can be distinguished by using valueθand Rs within the 100Hz-6.31 KHz frequency range. Kiwi and peach can be distinguished by using value G within the 100Hz～100KHz frequency range. Within 15.8 KHz-100 KHz frequency range, kiwi(Hayward, Qinmei) and peach(Qinwang, Qinguang No 2) the four kinds of fruit can be distinguished by using value Z. Within 100Hz～158KHz frequency range, the four kinds of fruit can be distinguished by using value Cp.3. Under the condition of being stored at room temperature (25℃), the relationship of 4 fruit quality parameters (firmness, total soluble sugar, total acid, Moisture content) and 3 electrical parameters (Z, Cp, Lp) were studied. The results showed that the effective forecast model can be established and electricity parameter can mark nectarine fruit quality for correlation coefficients are significant among them. The feasibility of the model was verified by practice test. The study indicated that it was feasible to estimate the fruit quality by using electrical parameters, which was significant and useful in both practice and theory.4. The relationship of fruit 14 Physical parameters and 6 electrical parameters were studied when fruits were storied at room temperature (20℃). The results showed that the correlation between electric parameters (Lp, G and D) and physical parameters was low. So it can not use the 3 electrical parameters to mark the variation of physiological indexes. Z, Cp andθcan be used as sensitive electric parameters to symbolize physiological changes of the fruits in the characteristic frequency. The characteristic frequency of Z is 0.1 kHz and 2.51 MHz; the characteristic frequency of Cp is 1MHz and 1.58MHz; the characteristic frequency ofθis 0.1 kHz.5. The physical parameters of firmness and total acid (TA) of fruits of’Qinmei’kiwi were increased and total soluble sugar (TSS) was decreased with the extension of storage time at room temperature (20℃). It indicated that membrane integrity of cell became low for relative electrical conductivity of fruits increases. The ethylene production rate and respiration production rate changed as single peak and the peak time of ethylene production rate was in advance. The reducing of content of starch and cellulose was positively correlated with the declining of fruit firmness. It is can be inferred that amylase and PE play a main role first, then Cx and PG according to the activity peak time of softening relevant enzymes of kiwi.6. In this part,’Hayward’kiwifruit of appropriate harvest and late harvest was treated as the material to investigate the effects of 0.5μL/L of 1-methylcyclopropene (1-MCP) on post-harvest physiological biochemistry during room temperature (20℃). The results were:1) 1-MCP inhibited ethylene production speed and respiration intensity.2)1-MCP inhibited the lose of ’Hayward’ kiwifruit firmness, titratable acids and vitamin c (Vc) content.3) 1-MCP increased the activity of the Peroxidase (POD), catalase (CAT) and Superoxide dismutase (SOD). In brief,1-MCP treatment delayed kiwifruit’s ripening and softening. Compared with the degree of ripenessⅠ, kiwifruit of degree of ripenessⅡwas not suitable for preservation because the firmness falling was faster than the periodⅠ. Meanwhile, ethylene production rate was higher than periodⅠand the peak time was in advance. Z can distinguish different maturity of kiwi at characteristic frequency of 1MHz. Cp was an indicator to pick out different maturity of kiwi at characteristic frequency of 10 KHz.7. The kiwi falling from a height of 50 cm and 80cm onto a smoothly marble floor were used to investigate the effects of injury on such firmness, MDA, activities of lipoxygenase (LOX) of’Hayward’ kiwifruits. The results showed that:1) the effect of mechanical damage on firmness was the biggest.2) the treatment was increasing ethylene production speed and respiration intensity.3) the process of aging and softening of fruits were faster due to the increase of O2- production rate, LOX and MDA. Meanwhile, damage treatment could cause the change of electric parameters but not affect the overall change trend. Damage treatment could cause the decrease of Z and the increase of Lp and D but it could not affect Cp,θand G in frequency of 100 KHz,251KHz,631KHz and 1MHz. Z can distinguish the wounded and the controlled fruits at characteristic frequency of 100KHz、251KHz、631KHz和1MHz. D can distinguish the wounded and the controlled fruits at characteristic frequency of 100KHz、251KHz.更多还原