漂烫对速冻苹果丁过氧化物酶活性及品质的影响

为了优化速冻苹果丁漂烫工艺,以新鲜富士苹果(切分为1.5 cm×1.5 cm×1.5 cm的小丁)为研究对象,采用响应曲面法,建立漂烫时间、漂烫温度、料液比对POD相对酶活影响的二次多元回归数学模型,并分析漂烫对其品质的影响。结果表明:抑制速冻苹果丁POD酶活性的最佳漂烫条件为:漂烫时间4.5 min、漂烫温度92℃、料液比1∶11(g/m L);未漂烫速冻苹果丁的ΔE值升高了36.10,感官品质降低了34.46,可溶性固形物、可滴定酸及VC损失率分别为28.25%、17.67%、20.13%,漂烫后速冻苹果丁的ΔE值升高了5.57,感官品质降低了7.27,可溶性固形物、可滴定酸及V_C损失率分别为24.42%、10.85%、12.16%。表明漂烫处理较好地保持速冻苹果丁的品质。      

速冻黄瓜、藕的烫漂处理

将新鲜黄瓜、藕通过几种不同的烫漂处理，速冻后冻藏1个月，期间定时对样品进行检测，以确认最佳烫漂处理方式。试验结果表明：黄瓜烫漂30S、藕烫漂35S时冻藏效果最好，可保持黄瓜和藕的色泽、风味、质地，以及VC等营养成分。     

微波烫漂对速冻怀山药品质的影响

采用不同的微波烫漂水平处理怀山药,通过测定过氧化物酶活性、多酚氧化酶活性、失重率、可溶性固形物含量和游离氨基酸总量5项指标,研究微波烫漂对速冻怀山药品质的影响。同时对护色剂处理、热水烫漂、微波烫漂3种不同处理条件下怀山药解冻后的硬度、质地以及感官特性进行比较。结果表明：微波烫漂怀山药短时间内即可达到灭酶效果,而且营养成分损失少,解冻后品质较好。最佳的微波功率及相应的处理时间为407.6W和60s。     

漂烫对蔬菜果实质地的影响及低温漂烫作用的机理

漂烫处理是蔬菜和水果加工中主要的工艺之一,其目的是钝化果蔬中的氧化酶,防止品质劣变。漂烫通常是在接近沸点的热水中进行,导致产品质地下降。低温漂烫处理能激活果胶甲酯酶(PE)活性,其产物经由不同途径形成大分子果胶,改善了漂烫后或最终产品的质地。      

漂烫对蔬菜果实质地的影响及低温漂烫作用的机理

漂烫处理是蔬菜和水果加工中主要的工艺之一,其目的是钝化果蔬中的氧化酶,防止品质劣变。漂烫通常是在接近沸点的热水中进行,导致产品质地下降。低温漂烫处理能激活果胶甲酯酶(PE)活性,其产物经由不同途径形成大分子果胶,改善了漂烫后或最终产品的质地。     

漂烫和冻结对马铃薯细胞结构和质地特性影响的实验研究

质地特性是评估冻制果蔬质量优劣的重要指标。研究了漂烫和冻结对马铃薯惩质地特性的影响,发现低温短时间漂烫对马铃薯质地影响较小,速冻或慢冻都会大幅度地降低马铃薯的质地特性,速冻比慢冻好,马铃薯的质地特性与加工过程中细胞受损情况有一定关系。     

速冻毛豆漂烫工艺

研究了毛豆的不同漂烫工艺,试找出最佳漂烫方式,通过对过氧化物酶失活率、蛋白质、抗坏血酸、叶绿素含量的变化及感官评定等来衡量微波处理、声热处理和热水漂烫对毛豆品质的影响.试验结果表明,声热处理1 min能有效地钝化过氧化物酶,减少蛋白质、抗坏血酸和叶绿素的损失,同时提高了毛豆的感官品质.     

速冻花椰菜漂烫工艺的研究

对速冻花椰菜的漂烫工艺进行了研究,通过单因素试验和中心组合试验分析了漂烫时间、漂烫温度对花椰菜过氧化物酶活性和Vc含量的影响,结果表明将半径1.5~2.0cm的单花球切片置于92.97℃的15倍质量的水中漂烫1.47min的效果很好,单花球切片的过氧化物酶活性率为6.6%、Vc的损失率为10.3%,达到Vc的损失率不超过13%和过氧化物酶活性率小于7%的工艺要求。     

烫漂及冻藏时间对速冻香椿品质的影响

采用不同的处理方法及冻藏时间对速冻香椿进行试验,结果表明:烫漂和速冻可引起香椿Vc、蛋白质、干物质含量的减少;随着冻藏时间的延长水分、Vc的含量会逐渐减少,蛋白质、干物质的含量会呈现先降后升的趋势。     

Effects of low temperature blanching on texture,microstructure and rehydration capacity of carrots

The effect on quality of stepwise blanching (first 10 min at 65 °C, 50 min holding time, and 1 min at 95 °C) prior to drying of carrot slices was compared with conventional blanching (95 °C, 1 min). As quality parameters, rehydration capacity (effective diffusivity D_e, equilibrium moisture content W_e), texture (puncture test) and microstructure (SEM and Cryo‐SEM) were chosen. Non‐significant differences were found between the W_e of stepwise blanched samples and conventionally blanched ones, both values being similar to the moisture content of fresh carrots. D_e of conventional blanched carrots was higher than for stepwise blanched ones. Maximum force of stepwise blanched samples was higher than those of conventionally blanched ones and not significantly different from fresh carrots. Microstructural observations showed that stepwise blanching preserved cell to cell contacts better than conventional blanching; this fact was attributed to pectin‐methyl‐esterase activation at 65 °C, resulting in the differences in the maximum force between both treatments. Conventionally blanched samples tended to separate along their cell walls, forming voids among the phloem parenchyma cells. These voids would be filled with water during rehydration, thus showing the slightly higher W_e and the higher D_e for conventionally blanched carrots. Copyright © 2005 Society of Chemical Industry     

冻藏于不同温度下做不同处理方法的草鱼肉质构变化的研究

研究了草鱼的冻藏温度和质构之间的关系。将草鱼背部肉分为不作处理的对照组和镀冰衣组,将两组草鱼样品分别在-18、-25、-30、-80℃4个温度下共贮藏360d,每隔15d对草鱼肉进行质地多面剖析(Texture Profile Analysis,TPA)模式的测定。选用硬度、恢复性、弹性、胶黏性和咀嚼性这五个指标作分析。结果表明,随着冻藏时间的延长,各项指标均都在下降。冻藏于-80℃下的草鱼肉的各项指标最高,冻藏于-18℃下的草鱼肉的各项指标则最低。同时发现,在同一冻藏温度下,镀冰衣组的各项指标要高于对照组的各项指标。     

钙处理对干装苹果罐头质地的影响

采用质地多面分析方法(TPA),以清水处理为对照,研究碱性钙(氧化钙、氢氧化钙)、无机钙(氯化钙、碳酸钙、硫酸钙)、有机钙(乳酸钙、醋酸钙、丙酸钙)对干装苹果罐头质地参数(硬度、回复性、弹性指数、咀嚼性、内聚性)的影响,并对TPA参数之间及其与感官品质间的相关性进行了研究。结果表明:与对照相比,除硫酸钙以外,各处理对干装苹果罐头质地均有明显的影响,经碱性钙(氧化钙和氢氧化钙)处理的干装苹果罐头硬度适中,回复性、弹性指数、咀嚼性、内聚性、感官品质均较好。回复性、弹性指数、咀嚼性、内聚性之间的相关性均显著,硬度与感官品质之间呈显著正相关关系。表明碱性钙对干装苹果罐头有较好的作用,并保持良好的质构。      

烫漂方式对苹果脆片褐变和多酚及其抗氧化活性的影响

为阐明烫漂方式对热风干燥苹果片品质特性的影响,采用热水、蒸汽和微波对苹果片进行烫漂处理,测定苹果片在烫漂和干燥过程中的色泽、多酚及其抗氧化活性的变化情况。结果表明,热水烫漂苹果片的干燥时间最短,为270 min;不同烫漂方式对苹果片褐变有显著影响(P<0.05),其中热水烫漂的苹果片色泽变化最小,微波烫漂的苹果片色泽最差;与鲜样相比,烫漂方式对苹果片还原糖含量影响较小;干燥过程中微波烫漂的苹果片中产生的5-羟甲基糠醛含量最高,蒸汽烫漂次之,热水烫漂最低;苹果片经热水烫漂和干燥后维生素C损失率分别为34%和52%,而蒸汽烫漂和微波烫漂的苹果片中维生素C损失率较小;热水烫漂的苹果脆片总酚含量最高,达到11.82 mg GAE/g DW;苹果片经烫漂处理后游离多酚和结合多酚单体无显著性变化(P>0.05),但干燥后,所有样品中结合多酚单体含量均显著提高(P<0.05)而游离多酚单体的含量无显著性变化(P>0.05),表明3种烫漂方式都有利于多酚单体的保留;多酚抗氧化能力实验表明烫漂和干燥后苹果片中结合多酚抗氧化活性有显著性变化(P<0.05),其中热水烫漂的苹果...     

Comparison of several blanching methods on the texture and ascorbic acid content of frozen potatoes

The effect of stepwise blanching and a mixed method, in which the first step of the stepwise blanching was replaced by a short microwave treatment, have been compared with the conventional process for blanching potatoes for freezing with respect to physical and sensory properties, and ascorbic acid content. After freezing and reheating the mixed method produced a similar texture to that obtained with stepwise blanching, and both were significantly better than conventional blanching. The mixed method shortened the process time and improved retention of ascorbic acid.     

保脆剂对腌制大头菜质构特性的影响研究

采用氯化钙、乳酸钙、丙酸钙3种保脆剂对腌制大头菜进行保脆处理,利用质构仪质地多面分析(TPA)方法定时测定大头菜腌制期间硬度、脆度、弹性、咀嚼性、黏附性和凝聚性6个质构参数的变化情况,并分析各质构参数之间的相关性。结果表明,在腌制期间,TPA测试反映了经保脆剂处理后的大头菜各项质地参数总体呈先上升后下降的趋势,且不同保脆剂间各质地参数下降规律有所差异。大头菜的黏附性和硬度、脆度、弹性、咀嚼性、凝聚性均呈负相关;硬度和脆度具有高度的正相关性(R=0.966);咀嚼性与弹性、凝聚性、硬度呈较好的相关性(R=0.876、R=0.964、R=0.923);凝聚性和硬度、脆度的相关性较好(R=0.934、R=0.919)。     

常温不同时期1-MCP处理对富士苹果质地的影响

为了研究采后不同时期1-MCP处理对富士苹果果肉软化的影响,本实验采取质构仪质地多面分析法（TPA）对不同时期1-MCP处理的富士苹果果肉质地进行分析。结果表明:果肉脆度与硬度、凝聚性呈显著地正相关,凝聚性与咀嚼性呈显著地正相关,黏着性与其他参数呈负相关,回复性与咀嚼性呈显著性正相关,咀嚼性与硬度、凝聚性、回复性呈显著的正相关。1-MCP处理能够延缓果实脆度、凝聚性、回复性、咀嚼性的降低,抑制黏着性的增加,从而抑制了果实的软化,但效果随着处理时间的延长而降低。常温下1-MCP处理最好不超过5d。      

Effect of blanching in water and sugar solutions on texture and microstructure of sliced carrots

Thermal processing of vegetables has pronounced effects on the cell structure, often negatively affecting the final textural properties of the product. In order to study the effect of thermal processing and the protective effect of sugars on the tissue, sliced carrots were subjected to blanching treatments under different time and temperature combinations both in water and in 4% sugar solutions made of trehalose or maltose. The influence of these process conditions on mass transfer, texture, and microstructure (Cryo-scanning electron microscopy) was thus investigated. The total mass loss of all the samples blanched in water was associated to their cook value (C(100)(18)) except for the overprocessed one (90 °C, 10 min) that showed a total mass change significantly lower due to water uptake. The use of trehalose and maltose in the blanching solution reduced the solute loss while increasing the water loss. Microstructural analysis of the differently blanched carrots showed detachments between adjacent cell walls as well as plasmolysis phenomena as the time and temperature of the thermal treatment were increased. A protective effect of both sugars on cell structures was observed mostly in the sample treated at 90 °C. At macroscopic level, textural changes upon blanching were observed by a penetration test. As blanching time was increased, samples processed at 75 °C showed a hardness increase, while those processed at 90 °C showed a hardness decrease. However, both trehalose and maltose did not exert significant effects on the textural properties of blanched carrots when compared with those blanched in water. Practical Application: The results of this study could offer interesting perspectives in the optimization of the heat treatments in order to preserve the quality of semi-finished processed vegetables. Furthermore, the microstructural analysis is nowadays an important investigation tool that could contribute to a deeper understanding of both the effects of processing and ingredients on the vegetable microstructure and its relationship with the changes occurring on the quality properties at macroscopic level.