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1.
为探究冷冻过程中退火条件对真空冷冻干燥固体果蔬食品模拟体系冰晶结构、干燥特性、微观结构和质构的影响,该试验通过建立真空冷冻干燥果胶-蔗糖凝胶体系模拟果蔬天然网络结构,考察了不同退火条件对冷冻模拟体系的冰晶结构、冷冻干燥模拟体系的微观结构和质构等品质的影响。结果表明,退火温度范围和退火次数是影响冰晶结构、干燥过程和产品质构的重要因素。研究发现,冷冻模拟体系冰晶的直径均值、冰晶比例随退火温度范围增加和退火次数增加而降低;模拟体系的冷冻干燥速率随退火温度范围和退火次数增加而加快;冻干模拟体系的硬度和脆度随退火温度范围和退火次数增加而降低。采用0℃退火3次条件下,干燥时间最短约为14.0 h,此时模拟体系冰晶分形维数为1.616,冰晶直径极差为0.98 mm,直径切尾均值为0.16 mm,冰晶比例为75.00%,在脆度阈值为0.784 N时脆度保留效果最好,峰个数为4.33。相关性分析结果表明,模拟体系的干燥时间与冰晶直径分布的离散程度、直径均值呈正相关,与分形维数呈负相关,与冰晶的直径均值和退火到达温度呈正相关。该研究明确了退火条件对模拟体系冰晶形态和冻干后多孔结构的影响,可为真空冷冻干燥食...  相似文献   

2.
为明确氮肥用量和采收株高影响油蔬两用型油菜品种菜薹糖分积累的机制,以富硒1号油菜品系为材料,采用裂区试验设计,研究了3个氮肥水平(120、180和240 kg·hm-2)和4个采收株高(20、30、40和50 cm)对菜薹糖组分含量的影响,比较了菜薹中蔗糖代谢关键酶转化酶(INV)、蔗糖合成酶(SS)和磷酸蔗糖合成酶(SPS)活性的变化,并对糖代谢关键酶活性基因的表达量进行了分析。结果表明,淀粉含量随着施氮量的增加而降低,其他糖分含量在施氮量为180 kg·hm-2时显著高于其他施氮处理,表明过高和过低施氮量均不利于菜薹糖分积累。就不同采收株高而言,菜薹中果糖、淀粉、葡萄糖和蔗糖含量在株高20 cm采收时最高;海藻糖和山梨醇含量在株高40 cm采收时显著高于其他处理。菜薹SPS活性在各施氮量和采收株高处理下均比INV和SS活性低,表明菜薹中蔗糖以分解成小分子单糖如葡萄糖、果糖等代谢活动为主。在菜薹各采收时期和施氮量处理下,蔗糖分解体系的蔗糖合成酶SUS1/SUS4、SUS3和转化酶A/N-INVACINV1、CINV2等基因表达模式互补且为上调,增强了蔗糖的分解,而对蔗糖磷酸合成酶SPS1/SPS2的表达量影响很小。本研究结果为油蔬两用型油菜薹品种合理氮肥运筹提供了理论依据。  相似文献   

3.
琼胶寡糖对秋葵生长及品质的影响   总被引:1,自引:0,他引:1  
为探究琼胶寡糖作为叶面肥的效果,本研究以秋葵为试验材料,以复合肥作为基肥(对照),在秋葵的生长过程中分别增施0.2‰琼胶寡糖(0.2‰ OA)、海藻肥基肥(SF),测定秋葵的生长指标、果实参数及营养品质。结果表明,与对照相比,0.2‰ OA显著促进了秋葵植株的生长并提高了果实产量和营养品质(P<0.05)。0.2‰OA组的秋葵产量较对照提高41.56%,果实中营养物质黄酮、果糖、果胶、游离氨基酸、可溶性糖和Vc分别增加0.39个百分点、29.33%、93.28%、36.09%、19.75%和18.14%。海藻肥的促进效果虽稍逊于琼胶寡糖,但与对照相比仍有显著改善(P<0.05)。SF组产量较对照提高14.74%,其营养物质黄酮、果胶、游离氨基酸、可溶性糖和Vc分别增加0.31个百分点、27.67%、13.26%、6.00%和5.07%。综上,琼胶寡糖能够明显改善果蔬的生长及品质,在高品质果蔬的生产中具有较大应用潜力。本研究结果为琼胶寡糖在高品质农业生产中的应用提供了理论依据。  相似文献   

4.
为探究钙盐作为冷冻保护剂与高浓度糖液浸渍组合在常温下进行渗透脱水处理对冷冻蓝莓融化后质地品质的影响。对比以丙酸钙、乳酸钙、氯化钙为代表的3种钙盐冷冻保护剂及质量浓度为0.5、1.5、3.0、5.0 g/mL丙酸钙处理对冻融蓝莓品质的影响。通过观测蓝莓冻融后外观,测定硬度值、弹性、咀嚼性、胶着性、内聚性和回复性品质指标及可溶性果胶、共价结合型果胶和离子结合型果胶的含量。结果表明:添加钙盐结合糖液渗透脱水处理组均可减少蓝莓冻融后皱缩和质地瘫软现象,丙酸钙结合糖液渗透脱水处理组的汁液流失率比对照组降低约25.42%,显著低于(P<0.05)其他处理组,丙酸钙处理组为较优的钙盐添加种类。对丙酸钙添加浓度进行优化筛选,发现当丙酸钙添加浓度为1.5 g/mL时可显著降低( P <0.05)蓝莓果实的汁液流失和细胞膜透性,冻融后硬度为1.54 N、弹性0.75 mm,可溶性果胶、共价结合型果胶和离子结合型果胶含量分别达到1.03、0.83 和0.68 mg/g,减少蓝莓果实的质地瘫软现象并保持最佳冻融品质。丙酸钙浓度为1.5 g/mL结合渗透脱水技术使冻融蓝莓具有更好的品质,有利于食用和加工。研究结果不仅为解决蓝莓加工行业出现的由于长期冷冻所造成果实质地瘫软问题提供数据基础,还为研发提升果蔬原料冷冻贮藏品质的助冻剂及改性技术提供一定的理论依据。  相似文献   

5.
为探究不同果蔬化学组分与细胞结构之间的差异及其对质地特性的影响,本研究对6种不同果蔬原料的化学成分、细胞微观结构、力学特性及质地特性进行分析。结果表明,苹果与梨的果糖含量较高,苹果的细胞结构较大;桃中蔗糖、水溶性果胶(WSP)与总酸的含量较高,细胞较小且排列密集,与其他果蔬差异较大;马铃薯与山药之间的差异主要体现在细胞结构方面。统计分析结果表明,纤维素(CEL)含量与应力-松弛特性参数均呈极显著正相关(P<0.01);蔗糖、WSP含量与质地剖面分析(TPA)特性参数均呈极显著负相关(P<0.01);颗粒密度、孔隙度与部分应力-松弛特性参数和质地特性呈极显著正相关(P<0.01);细胞壁厚度、微观结构参数与部分质地特性呈显著正相关(P<0.05)。研究发现,影响新鲜果蔬质地特性的3个核心指标为黏滞系数(η)、体积密度、螯合性果胶(CSP)含量。本研究可为果蔬原料保鲜与加工利用提供一定的理论依据。  相似文献   

6.
张露露  刘兴菊  马源  马晖玲 《核农学报》2022,36(9):1755-1765
为了探究2,3-丁二醇(2,3-BD)与凹凸棒石(PAL)复合使用对植物诱抗能力的提升效果,以草地早熟禾纳苏(Poa pratensis Nassau)为试验材料,2,3-BD-PAL为复合诱导制剂,立枯丝核菌(Rhizoctonia solani)为接种病原物,对未诱导接菌、2,3-BD诱导接菌和2,3-BD-PAL复合诱导接菌后的植株叶片中细胞壁组成物质及细胞壁降解酶活性进行数据分析。结果表明,在病原菌胁迫期间,各处理组植株叶片中羧甲基纤维素酶(Cx)、β-葡萄糖苷酶(β-Glu)、滤纸酶(FPA)、果胶甲基半乳糖醛酸酶(PMG)和多聚半乳糖醛酸酶(PG)活性均显著升高,而多聚半乳糖醛酸反式消除酶(PGTE)和果胶甲基反式消除酶(PMTE)活性变化不明显,其中Cx起主要降解作用。在胁迫3 d时,未诱导叶片Cx、β-Glu和PG等酶活性快速上升到最大值,而诱导处理有效抑制了酶活的增加。草地早熟禾经2,3-BD-PAL复合诱导处理后,能够稳定纤维素含量,高效促进果胶合成和木质素积累,抑制菌丝入侵,更大程度上降低Cx、β-Glu和PG等降解酶对细胞壁的破坏程度,其诱抗效果优于2,3-BD单独诱导处理。综上,2,3-BD与PAL复合诱导能够增强2,3-BD的诱导效果,提高植物抗病性,为2,3-BD在农业生产中的广谱性应用奠定了理论基础。  相似文献   

7.
为明确低O2高CO2贮藏环境对马铃薯块茎淀粉-糖代谢的影响,本试验以大西洋马铃薯为试验材料,研究体积分数为5%O2+2%CO2(CA1)、5%O2+4%CO2(CA2)、5%O2+6%CO2(CA3)、5%O2+8%CO2(CA4)及5%O2+10%CO2(CA5)的气体环境对马铃薯在4℃贮藏期间块茎中糖类、淀粉及淀粉-糖代谢相关酶[腺苷二磷酸葡萄糖焦磷酸化酶(AGPase)、尿苷二磷酸葡萄糖焦磷酸化酶(UGPase)、淀粉磷酸化酶(SP)及转化酶(INV)]活性的影响,并对块茎中还原糖含量的变化与淀粉-糖代谢相关因子进行相关性分析。结果表明,适宜的低O2高CO2贮藏环境可有效抑制淀粉含量、AGPase活性、UGPase活性的下降,并且能够抑制还原糖、蔗糖、果糖、葡萄糖含量及SP、INV活性的上升,CA1环境贮藏的马铃薯块茎在整个贮藏期间淀粉含量显著高于CK(P<0.05),还原糖、蔗糖、果糖及葡萄糖含量显著低于CK(P<0.05),AGPase、UGPase活性显著高于CK(P<0.05),而SP、INV活性均显著低于CK(P<0.05);相关性分析结果表明,还原糖含量与淀粉含量、AGPase活性、UGPase活性呈极显著负相关(P<0.01),与葡萄糖含量、果糖含量、SP活性及INV活性呈极显著正相关(P<0.01)。综上,马铃薯在CA1(5%O2+2%CO2)环境下贮藏可有效延缓块茎低温贮藏期间“糖化”现象的出现,AGPase、UGPase、SP、INV在贮藏过程中起到了一定的调控作用。本研究结果为加工型马铃薯的安全贮藏及明确“低温糖化”机理提供了理论依据。  相似文献   

8.
李佩艳  尹飞  党东阳  甘瑞卿  李鑫玲  梁华 《核农学报》2020,34(12):2742-2748
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。  相似文献   

9.
为了解决香蕉贮运过程中常温运输品质劣变较快、贮运后乙烯催熟程度不可控制的问题。该研究以低成熟度香蕉为模拟贮运试材,研究红、橙、黄、绿、蓝、紫色LED单色光在常温(20 ℃)模拟贮运过程中延缓保鲜和催熟调控作用,以确定香蕉在不同波段光色照射下的后熟和品质变化。结果表明,蓝、紫光可以通过抑制香蕉呼吸强度和乙烯释放量,与无光照相比有效延长香蕉2 d的贮藏期、减少纤维素分解为果胶、防止硬度软化、抑制色泽转黄和淀粉-糖转化,蓝光的延缓后熟能力比紫光更好。红、橙光LED照射可以促使呼吸和乙烯高峰提前2 d,促进表皮转色,增加蔗糖、果糖和葡萄糖累积,从而有效促进香蕉成熟,橙光比红光照射的催熟效果更缓慢,可以达到精准催熟的效果。黄、绿光照射会扰乱香蕉的后熟进程,缩短2 d贮运期,在表皮转色程度较低的情况下累积更多丙二醛,并抑制呼吸、乙烯释放、淀粉-糖转化和纤维素降解作用,使香蕉在未完全后熟的情况下提前进入衰老腐烂阶段。总体来说,不同波段的6种LED光色处理香蕉,可以表现出延缓后熟、促进后熟和扰乱后熟3种不同的效果。研究结果为LED光照技术被更多的应用和研究在果蔬采后保鲜领域提供基础数据,也为节能保鲜和可调控催熟技术应用于香蕉实际生产提供参考依据。  相似文献   

10.
栖热菌4-α-糖基转移酶对马铃薯淀粉的改性作用   总被引:2,自引:2,他引:0  
该文将栖热菌4-α-糖基转移酶(TSαGT)作用于马铃薯淀粉,分别利用理化分析、质构TPA分析及酶解分析等方法研究该酶对淀粉糊化、凝胶特性和消化性的影响。结果表明,TSαGT可以显著降低马铃薯淀粉中直链淀粉质量分数,使从初始的21%降低至15%,从而使淀粉糊冻融稳定性得以提高、糊透明度得到改善;对酶处理马铃薯淀粉凝胶的研究结果显示,TSαGT对淀粉的改性存在最适作用条件,控制0.024~0.06?U/g的酶用量作用30?min可以明显改善淀粉凝胶质构特性,使凝胶硬度降低,而弹性、咀嚼性、黏结性和胶着性得到不同程度的提高;进一步的消化试验结果表明,使用0.024?U/g以下的酶用量作用30?min,马铃薯淀粉的抗消化性得到提高,继续加大酶量则使抗消化性下降。因此,应用TSαGT对马铃薯淀粉改性处理,控制合适的酶作用程度可以显著提高马铃薯淀粉糊及凝胶的应用特性,同时增加其抗消化性。  相似文献   

11.
芒果皮富含膳食纤维、类胡萝卜素等生物活性化合物,但在食品工业中尚未被充分利用。为了实现芒果资源的全利用,本研究制备了含不同比例果皮和果肉的真空冷冻干燥重组芒果脆块,并考察了脆块的玻璃化转变温度(Tg)、质构、微观结构、类胡萝卜素含量等品质,综合分析了果皮和果肉比例对脆块理化、质构、营养和感官品质的影响。结果表明,添加芒果皮后脆块的硬度提高了2.65%~24.07%。当果皮含量超过20%时,脆度呈下降趋势,下降了1.91%~73.49%。此外,添加芒果皮后脆块的总酚、类胡萝卜素和膳食纤维含量分别增加了60.96%~336.75%、11.17%~112.48%和28.61%~166.36%。感官评价结果表明,芒果皮添加比例为40%以内的脆块综合品质得分均较高。综合考虑,添加20%芒果皮既可显著提高脆块的营养功能特性,改善质构稳定性,又具有较佳的综合感官品质。本研究结果表明,基于质构重组和真空冷冻干燥技术制备复合脆块是实现芒果皮资源利用的一种可行方法,这为生产中芒果皮的利用和添加量的选择提供了理论依据。  相似文献   

12.
FTIR-ATR spectroscopy and multivariate analysis were used for quantification of sugars in mango juices as a function of ripening. Calibration was based on sucrose/glucose/fructose mixtures, with six concentration levels and following a triangular experimental design. PLS1 regression of the spectra first derivatives gave the best results, enabling quantification of fructose, sucrose, and glucose with 1.4, 1.4, and 4.9% prediction errors, respectively. Throughout ripening, sucrose and fructose were accurately quantified by PLS-FTIR, whereas the accuracy of glucose determination decreased at later stages, when concentrations fell to 0.6-1.5 g/L. These results enabled a correlation with fruit ripening stage to be established. This may be particularly useful to detect over-ripening in fresh fruits, a period when other indicators (pH and % soluble solids (SS)) do not change significantly; this knowledge may help in predicting fruit stability to transport and storage. Similar information obtained for nonfresh juices (in which pH and %SS may be masked by additives), may help determine whether the source fruits had suitable ripening stages.  相似文献   

13.
不同变种甜瓜糖分积累及蔗糖代谢酶活性动态变化   总被引:1,自引:0,他引:1  
叶红霞  吕律  王同林  海睿  汪炳良 《核农学报》2019,33(10):1959-1966
为了解不同类型甜瓜糖分积累及糖代谢特点,选用厚皮甜瓜品种X228、普通甜瓜品种B154及越瓜品种H227为材料,定期取样测定果实成熟过程中的葡萄糖、果糖、蔗糖含量和蔗糖代谢相关酶活性,研究不同变种甜瓜果实发育过程中糖分积累及相关酶动态变化差异。结果表明,授粉15 d至果实成熟期间,3个甜瓜品种的果实葡萄糖与果糖含量的变化均较小,品种间差异不显著。3个甜瓜品种果实蔗糖含量存在显著性差异,其中H227果实几乎无蔗糖积累,葡萄糖和果糖是果实的主要糖组分;B154和X228果实蔗糖含量随着果实发育而快速增加,蔗糖积累存在明显的转折点,蔗糖是B154和X228这2个品种成熟果实中最主要的糖组分,且果实蔗糖含量提高的同时蔗糖磷酸合成酶(SPS)活性上升、酸性转化酶(AI)活性降低,蔗糖合成酶(SS)合成方向的活性与蔗糖含量关系不显著。根据蔗糖含量的差异,可将甜瓜分为蔗糖积累型和低蔗糖积累型两类,前者果实蔗糖含量的上升被认为是SPS活性上升与转化酶(特别是AI)活性下降共同作用的结果,后者果实内极低的蔗糖含量被认为是SPS活性较低导致的。本研究结果为甜瓜种质资源创新利用和甜瓜果实糖分积累调控研究奠定了理论基础。  相似文献   

14.
This study was conducted to investigate the formation of furan from sugars, ascorbic acid, and organic acids as affected by ionizing radiation and thermal treatments. Results showed that both thermal treatments and irradiation induced formation of furan from ascorbic acid, fructose, sucrose, or glucose. Little furan was produced from malic acid or citric acid. The pH and concentration of sugars and ascorbic acid solutions had profound influences on furan formation due to either irradiation or thermal treatment. The rate of irradiation-induced furan formation increased with decreasing pH from 8 to 3. Approximately 1600 times less furan was formed at pH 8 as apposed to pH 3. At the same pHs, the amounts of furan formed from irradiation of ascorbic acid, fructose, and sucrose were always higher than from glucose. As pH decreased from 7 to 3, an increase in thermally induced furan was observed for sucrose and ascorbic acid solutions, but for glucose solution, less furan was formed at pH 3 than at pH 7. The levels of sugars commonly found in fruits and fruit juices, upon irradiation, would be high enough to potentially produce low parts per billion (ppb) levels of furan. The concentration of ascorbic acid at which a maximum of furan was produced upon irradiation was about 0.5 mg/mL, a level commonly found in some foods. Five furan derivatives were tentatively identified in thermally treated ascorbic acid solution, while one furan derivative was tentatively found in both irradiated and thermally treated samples.  相似文献   

15.
The green monkey orange (Strychnos spinosa Lam., Loganiaceae), a tree indigenous to tropical and subtropical Africa, produces juicy, sweet-sour, yellow fruits containing numerous hard brown seeds. The species has recently been introduced into Israel as a potential new commercial crop. However, little is known about its agronomical performance, fruit development and ripening, or postharvest physiology. The current study shows that during ripening in storage, the peel color changes from green to yellow, accompanied by a climacteric burst of ethylene and carbon dioxide emission. Total soluble solids slightly increased during storage, whereas total titratable acidity and pH did not change significantly. The major sugars that accumulated during ripening in storage were sucrose, glucose, and fructose, and the main acids, citric and malic acids. The main volatiles present in the peel of ripe fruits were phenylpropanoids, trans-isoeugenol being the major compound.  相似文献   

16.
Higher populations of total fungi, bacteria and actinomycetes occur in the geocarposphere of peanuts than in bulk soil. One of the factors that affects exudation of organic substrate is Ca2+ concentration in the pegging medium. Plants of Arachis hypogaea L. cv. Argentine were grown axenically and the effect of three concentrations of Ca2+ on exudation of sugars from excised fruits at different stages of development was measured. The amount of total sugar exuded was greatest at 10 mg Ca2+ 1?1 in the bathing solution after 48 h. More sugar was exuded from peg sections than from older fruits and the difference depended upon whether results were expressed as mg sugar g?1 fruits or μg per fruit. Of the three sugars exuded the quantities decreased in the order sucrose, fructose, and glucose.  相似文献   

17.
The molecular compositions of rosemary ( Rosmarinus officinalis L.) extracts and their dependence on extraction solvents, seasons, and drying processes were systematically characterized using NMR spectroscopy and multivariate data analysis. The results showed that the rosemary metabonome was dominated by 33 metabolites including sugars, amino acids, organic acids, polyphenolic acids, and diterpenes, among which quinate, cis-4-glucosyloxycinnamic acid, and 3,4,5-trimethoxyphenylmethanol were found in rosemary for the first time. Compared with water extracts, the 50% aqueous methanol extracts contained higher levels of sucrose, succinate, fumarate, malonate, shikimate, and phenolic acids, but lower levels of fructose, glucose, citrate, and quinate. Chloroform/methanol was an excellent solvent for selective extraction of diterpenes. From February to August, the levels of rosmarinate and quinate increased, whereas the sucrose level decreased. The sun-dried samples contained higher concentrations of rosmarinate, sucrose, and some amino acids but lower concentrations of glucose, fructose, malate, succinate, lactate, and quinate than freeze-dried ones. These findings will fill the gap in the understanding of rosemary composition and its variations.  相似文献   

18.
The loss of crystalline structure in sucrose, glucose, and fructose has been shown to be due to the kinetic process of thermal decomposition (termed apparent melting), rather than thermodynamic melting. The purpose of this research was to investigate whether or not it is possible to scan quickly enough to suppress the kinetic process of thermal decomposition and reach the thermodynamic melting temperature of these sugars using a new rapid-scanning DSC. Indium, a thermodynamic melting material, and sucrose, glucose, and fructose were analyzed at three heating rates from 1 to 25 °C/min using standard DSC and at seven heating rates from 50 to 2000 °C/min using rapid-scanning DSC. Thermodynamic melting was achieved when the onset temperature (T(m onset)) of the endothermic peak leveled off to a constant value independent of heating rate. The T(m onset) for indium was constant (156.74 ± 0.42 °C) at all heating rates. In the case of fructose, the T(m onset) increased considerably until a heating rate of approximately 698 °C/min, after which the average T(m onset) for the remaining three heating rates was constant at 135.83 ± 1.14 °C. Thus, 135.83 °C is proposed to be the thermodynamic melting temperature of fructose. It is important to note that the heating rate at which this thermodynamic melting temperature is achieved is most likely influenced by the type and amount of trace components (e.g., water and salts) contained in the fructose, which are known to vary widely in sugars. In the case of sucrose and glucose, thermodynamic melting temperatures were not able to be obtained, because the upper limit heating rate used was not fast enough to suppress thermal decomposition and achieve thermodynamic melting, perhaps due to the higher apparent T(m onset) for sucrose and glucose compared to that for fructose.  相似文献   

19.
A high pressure liquid chromatographic (HPLC) method has been developed which is fast, simple, specific, and reliable over a wide range of sugar concentrations in a variety of food matrices. With few exceptions, sample preparation is simple, requiring only a water-ethanol extraction, followed by a rapid mini-column cleanup before injection into the HPLC system. The majority of samples can be prepared for analysis within 1--1 1/2 hr, and the following sugars are separated in less than 45 min: fructose, glucose, sucrose, maltose, lactose, melibioals, chocolate products, chocolate sirups, cookies, health food products, molasses, preserves, processed fruits, and soy protein products.  相似文献   

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