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荔枝原产于我国南部,具有良好的经济价值,但同时也不易储藏保鲜,容易褐变。本文综述了国内外有关荔枝果皮褐变机理的研究进展,并对今后荔枝防褐技术研究的发展方向提出建议。 相似文献
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《中国食品学报》2016,(1)
为研究保鲜气调运输厢体内荔枝不同摆放位置对保鲜品质的影响,采用果蔬气调保鲜运输试验平台对"淮枝"荔枝进行气调贮藏。隔7 d对不同摆放位置的荔枝样品进行测试,测试指标为果皮褐变指数、质量损失率、果皮色差值、可滴定酸以及可溶性固形物含量,并结合厢体内的温度场、湿度场进行分析。试验结果表明:在贮藏期内,厢体内温度呈前低后高、上低下高分布;而相对湿度呈前高后低、上低下高分布。不同纵向摆放位置对无包装荔枝的果皮褐变指数、质量损失率影响较大,质量损失率自上而下逐步减小;处于厢体后部的荔枝的可滴定酸含量较前部和中部的荔枝要高;处于厢体中部的荔枝的可溶性固形物含量要比前、后部的荔枝低。本研究结果为果蔬贮运保鲜提供一定的参考。 相似文献
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为掌握荔枝果柄不同处理方式对其常温贮藏特性的影响,以"淮枝"荔枝为试验对象,分别在去柄、带柄和鲜插3种处理方式下,测定其褐变指数、色泽(L*,a*,b*值)、果皮含水率、果皮厚度、果肉可溶性固形物和可滴定酸含量等指标的变化。分析果柄处理对其耐贮性能的影响,结果表明:鲜插处理的保鲜效果依次优于带柄和去柄。鲜插处理可以抑制果皮a*值下降,延缓果皮褐变以及厚度降低,并且较好地维持了果皮含水率。对于3 d以内的短期贮藏,果柄对荔枝保鲜品质影响不大。超过4 d以后,果柄对荔枝果实外观色泽和风味的保持起到一定作用。该文可为荔枝贮藏保鲜技术与装备开发提供一定参考。 相似文献
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为研究保鲜模式对荔枝果实贮藏品质变化的影响,在模式可控的保鲜厢体上,以"桂味"荔枝果实作为试验材料,分别在气调、控温控湿和仅控温3种保鲜模式下,开展荔枝果实贮藏试验,比较不同保鲜模式对荔枝果实贮藏效果的影响。试验结果表明,贮藏20 d后,气调模式荔枝的好果率接近1.00,控温控湿模式好果率为0.81,仅控温模式荔枝好果率为0.59;在贮藏期前5 d,不同保鲜模式下的荔枝果实品质差异不显著;仅控温模式荔枝在贮藏过程中果皮水分百分含量迅速下降至0.57、果实失重率迅速增长至11.52%;气调和控温控湿模式下,荔枝果实失重率分别上升至2.91%和2.05%,果皮水分百分含量分别从0.73降至0.69和0.71;不同保鲜模式对荔枝果肉TSS和TA含量变化影响不显著;第20 d货架期试验表明,气调模式能够延缓荔枝果实货架期失重率的变化。研究结果为荔枝果实贮运方式选择提供一定的参考。 相似文献
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茶树油、丁香酚、柠檬醛在荔枝保鲜中的应用 总被引:1,自引:0,他引:1
本文研究了茶树油、丁香酚和柠檬醛的挥发性香氛对荔枝的保鲜作用,采用复配方法探究三种香料对荔枝的协同保鲜效果。结果表明:在冷藏(4±1℃)过程中,茶树油和丁香酚、柠檬醛的挥发性香氛可抑制荔枝果实腐败,延缓果皮衰老和果肉维生素C含量的降低,对保持荔枝果实的感官品质也具有积极作用;且三者复配后效果更佳,贮藏至18天,复配组荔枝的腐败率、果皮相对渗透率、维生素含量分别为对照组的56.0%、72.8%、124.8%,果皮颜色、果实滋味、果实气味和整体评价分别比对照组高2.4、3.3、2.6和3.4分。 相似文献
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荔枝与荔枝酒褐变控制 总被引:1,自引:0,他引:1
以荔枝及荔枝酒为试料,研究荔枝多酚氧化酶(PPO)的酶学特性及荔枝酒发酵过程中的褐变机理及控制措施。结果表明:荔枝PPO存在同功酶,荔枝PPO最适底物为没食子酸;以没食子酸为底物,荔枝PPO最适反应pH值为8.0,最适反应温度50℃,荔枝PPO的动力学参数为:米氏参数(Km)为26.033mmol/L,最大反应速度(Vmax)为34.816g/(L·min);荔枝PPO对酸碱、对热稳定性较差;荔枝酒发酵过程中褐变的主要原因是其PPO引起的酶促褐变。因此,低温贮藏和高温热处理可有效抑制荔枝及荔枝酒在贮藏和加工中酶促褐变反应。 相似文献
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不同温度和包装方式对荔枝保鲜品质的影响 总被引:6,自引:1,他引:5
为掌握温度和包装对荔枝货架期的影响,本试验以“淮枝”荔枝为试验材料,以裸露的荔枝和由开孔袋包装的荔枝,分别处于常温货架和低温货架,研究不同因素对荔枝质量损失率、褐变指数、好果率、色差、可溶性固形物含量和可滴定酸含量的影响。试验表明:低温货架和包装都能延长荔枝货架期,各品质指标整体衰变速度从快到慢依次为:常温裸露、常温包装、低温裸露、低温包装。对荔枝货架期影响因素中,温度占主要影响作用,低温货架有效的降低了荔枝各指标的变质速度;开孔聚乙烯薄膜包装也能降低荔枝品质的衰变,该影响小于货架温度的影响。常温货架无包装的荔枝好果率在30 h变为0,低温包装荔枝的好果率在60 h仍保有9.20%。与常温货架荔枝裸露的销售方式对比,采用低温货架并由开孔聚乙烯薄膜包装可以使荔枝货架期延长一倍以上。该文为荔枝货架期保鲜研究提供了参考。 相似文献
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以黑叶、禾荔、妃子笑3个广西大宗品种荔枝果肉为原料,经乳酸菌复合菌种发酵得到荔枝发酵饮料。 在此基础上,以发酵饮 料为研究对象,采用气质联用(GC-MS)法对比分析了3个品种荔枝发酵饮料的挥发性香气成分及含量。 研究结果表明,黑叶、禾荔、妃 子笑3个品种荔枝发酵饮料中共检出香气成分72、48、52种,主要以烯类和醇类为主。 黑叶、禾荔、妃子笑品种荔枝发酵饮料中含量最 高的挥发性香气物质分别为香茅醇(16.63%)、乙醇(17.62%)、顺式玫瑰醚(11.33%)。 三种荔枝发酵饮料的挥发性香气成分差异较 大,其中黑叶品种荔枝发酵饮料中致香成分最丰富,明显多于另外两种。 相似文献
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通过添加不同酵母多糖发酵荔枝酒以及采用不同酵母菌种发酵酿制荔枝酒,分别研究酵母多糖种类、添加量、添加时间以及酵母种类对荔枝酒理化指标、感官品质的影响及防褐变效果。结果显示,在荔枝汁中添加250 mg/L Optired酵母多糖,发酵所得成品酒酒精度为12.8%vol,总酸、挥发酸等理化指标均符合国标,可显著提高荔枝酒感官品质,同时对荔枝汁中酚类物质有良好的保护作用,成品酒总酚含量提高35.9%,明显延缓其褐变进程,加速褐变后其褐变率下降156.2%。采用富产多糖的酵母发酵,其酿制的荔枝酒果香酒香浓郁协调,口感醇厚,圆润丰满,在贮藏过程中能有效保持香气、色泽、新鲜度等感官质量的稳定性,其中酵母BM4×4最为适宜。 相似文献
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Liang Liu Shaoqian Cao Yujuan Xu Mingwei Zhang Gengsheng Xiao Qianchun Deng Bijun Xie 《Food chemistry》2010
The degradation of flavanols had been studied both in the litchi pericarp during the storage and in the model system containing PPO and flavanols of litchi pericarp. The results showed that (−)-epicatechin was the optimal endogenous substrate of litchi pericarp PPO, and the procyanidins of litchi pericarp were oxidised very slowly when incubated alone with PPO. However, (−)-epicatechin could accelerate the oxidation of the other flavanols in litchi pericarp through a coupled oxidation pathway. The results obtained allowed us to draw a conclusion that the oxidation of (−)-epicatechin was a precursor of litchi pericarp browning. A pathway of enzymatic browning of litchi pericarp was proposed as follows: with the loss of cellular compartmentation, the litchi pericarp PPO and flavanols mixed and, then, (−)-epicatechin was oxidised by the PPO and o-quinones formed. The o-quinones reacted with other flavanols and anthocyanins, accelerating the oxidation of other polyphenols. Finally, the oxidation of (−)-epicatechin and other polyphenols led to the formation of the brown-coloured compounds, resulting in the enzymatic browning of litchi pericarp. 相似文献
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采用气相色谱-离子迁移谱(Gas Chromatography-Ion Mobility Spectrometry,GC-IMS)和气相色谱-质谱联用(Gas Chromatography-Mass Spectrometry,GC-MS)分析了热杀菌和超高压前处理对荔枝汁及其乳酸菌发酵汁挥发性物质的影响。结果表明,GC-IMS共检出70种挥发性化合物,以酮类、醇类、酯类、醛类和萜类为主,热杀菌导致新鲜荔枝汁中的丙酸乙酯、2-甲基丙酸甲酯、苯甲醇和1-辛烯-3-醇等成分损失严重,经发酵后其中的丙酸丁酯、三甲基吡嗪、5-壬酮和2,5-二甲基噻吩等成分含量更丰富。而超高压前处理荔枝汁与新鲜荔枝汁组分相似,经发酵后其中的芳樟醇、2,6-二甲基吡嗪、顺式玫瑰醚、苯甲醛等成分含量更丰富;GC-MS共鉴定出51种挥发性化合物,以萜类、醇类为主,热杀菌导致荔枝汁中萜类和醇类含量分别降低了37.05%和31.61%,超高压前处理荔枝汁中萜类和醇类含量则较鲜汁分别增加了33.57%和80.07%,而热杀菌和超高压前处理发酵荔枝汁挥发性化合物总量较发酵前分别增加了46.93%和46.19%,且超高压前处理发酵荔枝汁是热杀菌发酵荔枝汁的2.11倍,更富有愉悦性香气。两种技术相结合,表明了超高压前处理能有效改善荔枝汁及其发酵汁的香气品质,为提升荔枝发酵汁的品质提供了参考价值。 相似文献
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S. Janjai B. Mahayothee N. Lamlert B.K. Bala M. Precoppe M. Nagle J. Müller 《Journal of food engineering》2010
Litchi (Litchi Chinensis Sonn.) is an important commercial fruit in Thailand and Vietnam. Litchi fruit is consumed both as fresh and dried products. Also most of the export of litchi is in the form of dried whole litchi fruit. Thermo-physical properties and drying model of litchi fruit is important for optimum design of litchi dryer. This paper presents moisture diffusivity, shrinkage and finite element simulated drying of litchi fruit. The moisture diffusivities of litchi were determined by minimizing the sum of square of deviations between the predicted and experimental values of moisture content of thin layer drying under controlled conditions of air temperature and relative humidity. The components in the form of cylinder for seed and seed stalk and slab for seed coat, shell and flesh were dried in thin layers at the air temperatures of 50, 60, 70 and 80 °C and relative humidity in the range of 10–25%. The mean diffusivity of flesh, seed and shell of litchi fruit increased with temperature and was expressed by the Arrhenius-type equation, but the diffusivities of seed coat and seed stalk were independent of temperature. The moisture diffusivities of seed coat and seed stalk were much lower than those of the other parts of the litchi. The shrinkage of litchi fruit has also been determined experimentally and it was expressed as a function of moisture reduction. A two-dimensional finite element model has been developed to simulate moisture diffusion in litchi fruit during drying. Shrinkage of the flesh and different component diffusivities of litchi during drying were also taken into account. The finite element model was programmed in Compaq Visual FORTRAN version 6.5. This finite element model satisfactorily predicts the moisture diffusion during drying. Moisture contents in the different components in the litchi fruit during drying were also simulated. This study provides an understanding of the transport processes in the different components of the litchi fruit. 相似文献