脉冲强光处理对双孢蘑菇贮藏品质的影响

为探索脉冲强光(IPL)处理对采后食用菌贮藏品质的影响,本试验以新鲜双孢蘑菇为原料,采用不同强度(28.8、48.0、67.2 mJ·cm^-2)的IPL进行前处理,研究其在25℃贮藏期间生理指标及品质的变化。结果表明,随着贮藏时间的延长,IPL处理能有效延缓双孢蘑菇开伞、质量损失、褐变及脂膜氧化,在一定程度上保持原有硬度。同时,IPL处理可显著抑制双孢蘑菇中过氧化物酶(POD)和多酚氧化酶(PPO)活性(P<0.05),可减缓其总酚和维生素C含量的下降(P<0.05),其中48.0 mJ·cm^-2处理组效果最佳;贮藏第8天,总酚和维生素C含量分别较对照提高39.06%、53.63%。本研究结果为IPL技术在控制食用菌品质方面的应用提供了一定的理论依据。     

草酸对冷藏去壳马蹄笋的保鲜效果及机制研究

为探讨外源草酸延缓采后去壳马蹄笋木质化和褐变的效果及其作用机制,本试验以马蹄笋为试验材料,笋去壳后于水和5 mmol·L^-1草酸溶液中浸泡10 min,而后晾干并于温度6 ±1℃,相对湿度80%~85%条件下贮藏10 d,测定其品质指标以及与木质化、褐变、抗氧化相关酶的活性和基因表达量。结果表明,草酸处理抑制了去壳马蹄笋切面的褐变(P<0.05),延缓了笋肉木质化(P<0.05);草酸处理抑制了呼吸速率、相对电导率、超氧阴离子自由基($O_2^{·-}$)产生速率以及丙二醛(MDA)、过氧化氢(H₂O₂)含量的上升,抑制了苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、肉桂醇脱氢酶(CAD)、多酚氧化酶(PPO)的活性及其编码基因的相对表达量(P<0.05),提高了超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性及其编码基因的相对表达量。综上,草酸处理能够有效抑制采后去壳马蹄笋的木质纤维化和褐变,延缓品质劣变。本研究结果为草酸在马蹄笋采后保鲜的应用提供了理论依据。     

60Co-γ辐照结合1-MCP处理对蓝莓贮藏品质的影响

为研究⁶⁰Co-γ辐照结合1-甲基环丙烯(1-MCP)处理对蓝莓贮藏品质的影响,以粉蓝蓝莓为试验材料,对采后蓝莓生理指标、营养指标及相关酶活性进行测定,研究0±0.5℃条件下6种处理(1.5 kGy辐照处理记为A、2.5 kGy辐照处理记为B、1.5 kGy辐照+1 μL·L^-1 1-MCP 处理记为C、2.5 kGy辐照+1 μL·L^-1 1-MCP处理记为D、1 μL·L^-1 1-MCP处理记为E,不进行任何处理记为F)对蓝莓贮藏品质的影响。结果表明,与对照(F)比较,4种处理(A、C、D、E)均能够抑制果实腐烂率的上升和风味指数的下降,延缓果实的生理代谢,更好地保持果实的营养品质和酶活性,而2.5 kGy辐照处理(B)降低了果实的硬度、L^*值、可溶性固形物含量和花色苷含量,加快了果实多聚半乳糖醛酸酶活性的上升。其中,在贮藏80 d时,A、B、C、D、E、F组蓝莓的腐烂率分别为24.94%、38.36%、13.87%、30.78%、22.96%和48.38%。因此,1.5 kGy ⁶⁰Co-γ辐照结合1 μL·L^-1 1-MCP处理蓝莓对果实的贮藏效果最好。本研究结果为蓝莓的贮藏保鲜提供了新思路。     

流态冰预冷近冰温贮藏对西兰花贮藏品质的影响

西兰花是深受人们喜爱的蔬菜,衰老黄化是其采后正常的生理代谢过程,也是引起西兰花品质劣变的主要因素。为此寻求开发有效、绿色安全的西兰花保鲜方法迫在眉睫。以甘肃特色高原蔬菜西兰花品种耐寒优秀为试材,研究流态冰预冷近冰温贮藏、0 ℃预冷4 ℃贮藏和对照不预冷4 ℃贮藏等3种处理方式对其贮藏品质的影响。结果表明,在整个贮藏期,流态冰预冷近冰温贮藏处理西兰花的叶绿素含量、萝卜硫素含量、Vc含量、氨基酸含量以及可溶性蛋白含量均显著高于0 ℃预冷4 ℃贮藏处理和不预冷4 ℃贮藏处理。与0 ℃预冷4 ℃贮藏和不预冷 4 ℃贮藏相比,流态冰预冷近冰温贮藏可以增加西兰花贮藏期萝卜硫素、总酚物质和多糖的含量。流态冰预冷近冰温贮藏可保持西兰花贮藏期营养品质,同时能够维持西兰花的功能成分,保持其商品价值。     

草酸处理对桂七芒果冷害及细胞壁代谢的影响

为探讨草酸处理对低温冷藏下芒果冷害及细胞壁代谢的影响,本试验以桂七芒果果实为试材,采用5 mmol·L^-1草酸溶液浸泡处理,以清水浸泡处理为对照,并于4℃贮藏,分析芒果的冷害指数、丙二醛(MDA)含量、相对电导率、硬度、细胞壁物质含量、细胞壁代谢酶的变化。结果表明,与对照组相比,草酸处理显著降低了低温贮藏14 d后桂七芒果果实冷害指数、MDA含量、相对电导率、原果胶和纤维素含量,显著降低了低温贮藏28 d后果实的硬度;显著提高了低温贮藏14 d后果实水溶性果胶含量及多聚半乳糖醛酸酶(PG)、果胶甲酯酶(PME)、纤维素酶(Cx)活性,显著提高了贮藏21 d后果实β-半乳糖苷酶(β-Gal)活性。综上所述,草酸处理能减轻桂七芒果冷害,维持采后果实细胞壁降解酶较高活性和水溶性果胶含量。本研究为揭示草酸减轻芒果果实冷害机制提供了依据,可为草酸应用于其他冷敏型果实的贮藏保鲜提供理论参考。     

采后红光处理对芥蓝芽菜生物活性物质的影响

为研究采后红光处理对不同贮藏温度下芥蓝芽菜中生物活性物质含量的影响,本试验设置了采后红光、白光和黑暗处理芥蓝芽菜试验,分析了不同贮藏时间其芥子油苷、维生素C、花青素和总多酚的含量及抗氧化能力的变化。结果表明,25℃贮藏时,芥蓝芽菜中芥子油苷含量在采后贮藏过程中逐渐降低,采后红光处理可显著延缓芥子油苷含量的下降。在贮藏1、2、3 d后,采后红光处理组芥蓝芽菜中总芥子油苷含量分别较黑暗处理组提高56.67%、146.31%、32.24%;此外,采后红光处理延缓了芥蓝芽菜中维生素C含量的下降,促进了花青素、总多酚物质的积累,提高了芽菜的抗氧化能力。10℃贮藏时,采后红光处理促进了芥蓝芽菜中花青素的积累,对其他抗氧化物质含量及抗氧化能力无显著影响。上述结果表明,25℃贮藏条件下采后红光处理可以有效延缓芥蓝芽菜中生物活性物质的下降,维持芽菜营养品质。研究结果表明采后红光处理在芥蓝芽菜采后品质维持方面有较大的应用前景。     

0℃贮藏下南美白对虾品质变化研究

为分析冰藏冷链运输条件下南美白对虾品质和微观结构的变化,本研究测定了0℃贮藏条件下南美白对虾的色差、质构、挥发性盐基氮(TVB-N)及其组分含量和蛋白质图谱的变化情况,并对其肌肉的微观结构进行观察。结果表明,随着0℃贮藏时间的延长,南美白对虾L^*值、质构以及肌原纤维蛋白和肌基质蛋白含量呈下降趋势。0℃贮藏条件下,TVB-N值与贮藏时间呈正相关;贮藏4 d后南美白对虾色泽、质构和肌肉微观结构开始出现明显变化,肌原纤维蛋白和肌基质蛋白含量明显下降,而碱溶性蛋白含量呈增加趋势;贮藏6 d后蛋白条带降解明显。综合考虑,建议0℃贮藏条件下南美白对虾的货架期为4 d。本研究结果为冷藏条件下南美白对虾提供了品质评价的方法。     

1- MCP和60Co-γ辐照处理对自发气调包装大五星枇杷贮藏品质的影响

为研究1-甲基环丙烯(1-MCP)熏蒸和⁶⁰Co-γ辐照处理对枇杷贮藏品质的影响,本研究以大五星枇杷为试验材料,对采后自发气调包装枇杷的腐烂指数、木质素、硬度、呼吸强度、乙烯生成速率、相对电导率、可滴定酸(TA)、可溶性固形物(TSS)以及苯丙氨酸解氨酶(PAL)、脂氧合酶(LOX)、多酚氧化酶(PPO)、过氧化物酶(POD)活性进行测定,研究6±0.5℃条件下1 μL·L^-1 1-MCP、1.5 kGy⁶⁰Co-γ、1 μL·L^-1 1-MCP+1.5 kGy ⁶⁰Co-γ不同处理对枇杷贮藏品质的影响。结果表明, 1-MCP和⁶⁰Co-γ复合处理效果最好,可延缓腐烂指数和木质素含量上升,维持果实硬度,降低果实呼吸强度、乙烯生成速率和相对电导率,保持果实TA和TSS含量,抑制PAL、LOX、PPO和POD活性的上升。在贮藏40 d时,1-MCP和⁶⁰Co-γ复合处理枇杷的腐烂指数仅为17.95%,而1-MCP组、⁶⁰Co-γ组、CK组分别为22.86%、25.72%和36.24%。因此,1-MCP和⁶⁰Co-γ复合处理对枇杷果实的贮藏效果最好。本研究结果为枇杷的贮藏保鲜提供了理论依据。     

热水处理对桃果采后青霉病及自然腐烂的控制

为了寻找一种能够代替化学杀菌剂控制桃果采后病害的方法,研究了热水处理对桃果采后青霉病的控制及对桃果贮藏品质的影响,探讨了热水处理对扩展青霉孢子萌发的影响.在测定不同温度、不同时间热水处理对桃果青霉病抑菌效果的基础上,选择54℃、2 min的条件对桃果进行热水处理,处理后的桃果放在20℃下贮藏7 d或在4℃下贮藏30 d再转移到20℃下贮藏7 d,观察桃果的腐烂情况,并对桃果的贮藏品质指标进行检测.试验结果表明:热水处理能够有效地起到控制桃果采后病害的作用,热水处理对桃果的失重率、硬度、总可溶性固形物含量、抗坏血酸含量、可滴定酸度等水果品质没有显著的不利影响.热水处理可以显著抑制扩展青霉孢子的萌发及芽管的延长.因此,54℃、2 min热水处理是一种能代替化学杀菌剂对桃果采后病害进行控制的有效方法.     

不同纳米改性LDPE膜对枇杷保鲜效果的影响

为探讨不同纳米改性低密度聚乙烯(LDPE) 膜对枇杷果实采后保鲜效果的影响,本试验分别研究了普通LDPE膜与纳米改性LDPE膜在室温条件下(20℃)对采后枇杷品质和生理特性的影响。结果表明,与普通LDPE膜相比,纳米Ag、纳米TiO₂和纳米SiO₂改性LDPE膜可显著抑制采后贮藏过程中枇杷果实的腐烂指数、褐变指数、失重率和硬度的上升及出汁率的下降;延缓其可溶性固形物、可滴定酸和Vc含量的降低;保持其贮藏后期较高的总酚、总黄酮含量和抗氧化能力;提高了对枇杷果实DPPH自由基和羟自由基的清除能力,有效延长了枇杷保质期,表明不同纳米改性LDPE膜可显著提高枇杷果实的保鲜效果。其中,纳米SiO₂改性LDPE膜包装处理能够更好地抑制枇杷果实品质的下降,保持更好的抗氧化能力,其作为枇杷果实采后保鲜包装具有潜在的市场前景。本研究结果为纳米改性LDPE膜在果蔬保鲜中的应用提供了理论参考。     

The effect of post-harvest and packaging treatments on glucoraphanin concentration in broccoli (Brassica oleracea var. italica)

The effects of post-harvest and packaging treatments on glucoraphanin (4-methylsulfinylbutyl glucosinolate), the glucosinolate precursor of anticancer isothiocyanate sulforaphane [4-methylsulfinylbutyl isothiocyanate], were examined in broccoli (Brassica oleracea var. italica) during storage times. The results showed that at 20 degrees C, 55% loss of glucoraphanin concentration occurred in broccoli stored in open boxes during the first 3 days of the treatment and 56% loss was found in broccoli stored in plastic bags by day 7. Under both air and controlled atmosphere (CA) storage, glucoraphanin concentration appeared to fluctuate slightly during 25 days of storage and the concentrations under CA was significantly higher than those stored under air treatment. In modified atmosphere packaging (MAP) treatments, glucoraphanin concentration in air control packaging decreased significantly whereas there were no significant changes in glucoraphanin concentration in MAP with no holes at 4 degrees C and two microholes at 20 degrees C for up to 10 days. Decreases in glucoraphanin concentration occurred when the broccoli heads deteriorated. In the present study, the best method for preserving glucoraphanin concentration in broccoli heads after harvest was storage of broccoli in MAP and refrigeration at 4 degrees C. This condition maintained the glucoraphanin concentration for at least 10 days and also maintained the visual quality of the broccoli heads.     

热水处理对采后鲜食蚕豆荚褐变及活性氧代谢的影响

为了提高鲜食蚕豆的保鲜效果,本试验以鲜食蚕豆果实为材料,研究了45℃热水处理10 min对鲜食蚕豆果实在常温(20℃)贮藏过程中豆荚褐变、种子品质及豆荚活性氧(ROS)代谢的影响。结果表明,45℃热水处理10 min能显著提高豆荚中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性,以及1,1-二苯基-2-三硝基(DPPH)自由基和羟基自由基清除率,显著抑制豆荚褐变指数、多酚氧化酶(PPO)和过氧化物酶(POD)活性的上升,抑制鲜食蚕豆豆荚中超氧阴离子($O_{2}^{\cdot -}$)生成速率、过氧化氢(H₂O₂)含量及丙二醛(MDA)的积累,减少褐变底物酚类物质的消耗,并延缓豆荚中叶绿素和抗坏血酸(Vc)的降解,同时保持蚕豆种子的好粒率、叶绿素和抗坏血酸含量。热水处理对种子中的蛋白质含量无显著影响。综上所述,45℃、10 min的热水处理提高了蚕豆豆荚的抗氧化能力,抑制了豆荚的褐变,保持了种子品质,延缓了鲜食蚕豆衰老过程,为鲜食蚕豆的保鲜提供了技术支撑。     

Desalination of sea water by akadama soil and akadama soil-inorganic adsorbents mixtures

(pp. 25–32)
The effectiveness of drip fertigation, which is known to control fertilizer application, for reducing nitrate in spinach and for improving the other qualities of spinach was investigated. Fertilizer application can be controlled effectively by drip fertigation. In 2002 and 2003, two spinach cultivars were grown in a plastic greenhouse with 4, 8 or 12 g N m⁻² of fertilizer application by drip fertigation, and with 8, 12 or 16 g N m⁻² of fertilizer application as a basal application. Nitrate concentration of petiole sap extracted by a garlic squeezer was significantly correlated with the water-extractable nitrate concentration. Nitrate concentrations of petiole sap extracted from plants treated with 12, 8 and 4 g N m⁻² of fertilizer by drip fertigation were constant, gradually decreased and significantly decreased, respectively, during the last 2 weeks. When nitrate concentration decreased during the last week, nitrate concentration in spinach at harvest was less than 3,000 mg kg⁻¹ FW. Thus it was thought that the pattern of the time course of nitrate in petiole xylem sap is a good indicator for getting spinach with low nitrate. The sugar concentration was negatively correlated with applied nitrogen quantity and the nitrate concentration. The total oxalic acid concentration in spinach treated by drip fertigation was significantly lower than that in spinach treated by basal application, independent of the amount of applied nitrogen. Thus drip fertigation is advantageous for improving crop quality.     

不同采收期对苹果常温贮藏品质和衰老的影响

以通辽地区的‘塞外红’苹果为试材,研究了生长发育期在116~134 d内的3个采收期果实常温(20±1)℃贮藏品质和软化衰老的变化,以确定‘塞外红’苹果的最佳采收成熟度和适宜采收期。结果表明,随着采收期的推迟,果实硬度逐渐降低,可溶性固形物和可滴定酸含量逐渐升高,种子颜色逐渐变褐到全褐。随着贮藏时间的延长,3个采收期果实的硬度、维生素C和可滴定酸含量均逐渐下降,从采收到贮藏结束,采期Ⅰ果实的硬度一直保持最高,采期Ⅱ保持了果实较高的维生素C和可滴定酸含量,采期Ⅲ果实的可溶性固形物含量SSC一直保持最高。结果还表明,采期Ⅰ的果实常温贮藏期间虽然具有较高的原果胶和纤维素含量,而且抑制了可溶性果胶的生成,推迟了果实多聚半乳糖醛酸酶PG活性和纤维素酶活性高峰,延缓了果实呼吸高峰和乙烯释放高峰的出现时间,但果实的外观色泽、口感和风味相对较差;采期Ⅲ的果实丙二醛和乙醇含量积累较多,果实衰老快。综合分析,采期Ⅱ的‘塞外红’苹果具有良好的内在品质、外观色泽和贮运性能。因此,建议通辽地区‘塞外红’苹果的采收期以9月5—10日为宜(可适当晚采1~2 d),采收成熟度参考标准为:果实生长发育天数123~128 d、果肉硬度11.0~11.5 kg/cm^2、SSC≥16.5%、种子的颜色3/4左右变褐、淀粉染色为4.5级左右。     

Long-term effects of lantana residue additions on water retention and transmission properties of a medium-textured soil under rice–wheat cropping in northwest India

Abstract. Hydraulic properties of soils after rice cropping are generally unfavourable for wheat cultivation. Poor drainage, delayed planting and oxygen stress in the root zone may adversely affect the wheat crop after lowland rice cultivation. We studied long-term effects of lantana ( Lantana spp. L.) residue additions at 10, 20 and 30 t ha⁻¹ yr⁻¹ (fresh biomass) on physical properties of a silty clay loam soil under rice–wheat cropping in northwest India. At the end of ten cropping cycles, soil water retention, infiltration rate, saturated hydraulic conductivity and drying rate of soil increased significantly with lantana additions. The available water capacity (AWC), on volume basis, declined at rice harvest (from 22.0 to 18.8–20.9%), but increased at wheat harvest (from 12.9 to 13.4–15.0%) after lantana treatment. The volumes of water transmission (>50 μm) and storage pores (0.5–50 μm) were greater, while the volume of residual pores (<0.5 μm) was smaller in lantana-treated plots than in controls at both rice and wheat harvest. Infiltration rate in the lantana-treated soil was 1.6–7.9 times that of the control (61 mm d⁻¹) at rice harvest, and 2–4.1 times that of the control (1879 mm d⁻¹) at wheat harvest. Thus lantana addition improved soil hydraulic properties to the benefit of the wheat crop in a rice–wheat cropping sequence.