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色值是反映浓缩苹果汁颜色深浅程度和衡量苹果浓缩清汁产品质量的重要理化指标。介绍了浓缩苹果汁色值测定的意义、色值测定的检测仪器和主要测定方法,重点研究了影响浓缩苹果清汁色值测定结果准确性的几个因素。 相似文献
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甘蔗赤腐病对甘蔗品质指标的影响 总被引:1,自引:0,他引:1
为了了解粤西甘蔗赤腐病对甘蔗品质指标的影响,对来自不同蔗区的3个品种,按田间自然感染赤腐病的不同级别进行了检糖化验分析。结果表明,赤腐病对甘蔗蔗糖分、纤维分、还原糖、重力纯度等品质指标均有不同程度的影响。各品种品质指标受影响的程度存在一定差异,以ROC22受影响最大,且发病级别越高品质指标受影响越大。ROC22发病最高级与最低级之间的平均蔗糖分、蔗汁还原糖、重力纯度均达差异显著水平,各级别的纤维分之间差异不显著。发病的与对照比平均蔗糖分减少1.86%~16.46%,纤维分下降2.15%~18.72%,重力纯度下降0.31%~7.45%,还原糖上升3.12%~103.57%。研究指出,赤腐病的为害是造成近年来粤西蔗区蔗糖分偏低的一个重要因素。 相似文献
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加热温度和时间对菜籽油质量影响的研究 总被引:9,自引:1,他引:9
就加热温度(120-200℃)和加热时间(0-8h)对菜籽油质量的影响进行了研究。结果表明:菜籽油酸值、过氧化值、丙二醛、羰基值随加热温度升高及时间延长而升高。在相同加热时间内,菜籽油玻值、过氧化值、丙二醛、羰基值与加热温度之间具有极显著的相关性,在加热2h过氧化值增加较快,然后增加趋于平缓,而加热2h的酸值增加较慢,但是在加热2-4h酸值增加却较快,酸值高峰滞后于过氧化值高峰2h;在相同加热温度下,除了菜籽油的过氧化值与加热时间具有显著相关性、在120℃下加热的菜籽油的拨基值与加热时间具有显著相关性以外,菜籽油的酸值、丙二醛、羰基值均与加热时间至极显著的相关性。 相似文献
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分别以富士及秦冠苹果为原料,研究了果胶酶PA和PP联合使用对两种浓缩苹果清汁加工过程中色值稳定性的影响,并对加工中超滤通量、树脂运行时间的影响进行了分析。实验结果表明:与单一使用PA果胶酶相比,复合果胶酶可以有效提高超滤、灌装工艺后苹果清汁的色值。确定了复合果胶酶的适宜添加量为PA为25 mL/t,PP为10 mL/t,适宜酶解时间为60 min。此工艺下,超滤清汁色值(T440)提高2.2%,灌装前后产品色值变化在3%以下,4 ℃下贮藏的日褐变量在0.05%以下;且每周期超滤平均通量及树脂有效运行时间均提高10%以上。PA和PP的联合使用是解决浓缩苹果清汁加工过程中色值下降且提高其贮藏稳定性的有效技术手段。 相似文献
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在甜菜制糖生产中,色值是考核中间制品质量和成品糖质量的主要技术指标之一,而色值的主要构成是还原糖的分解。因此分析探讨菜丝还原糖对色值的影响关系,对加工品质差,还原糖含量高的甜菜具有一定的指导意义。1996年,我厂甜菜自然碱度低,还原糖含量高。1996/97制糖生产期,我厂采用如下清净Xi艺:渐进预灰(4分钟)一冷主发热反应(8分钟,80-85℃)→一碳饱充(8分钟,88℃)→二碳饱充(5分钟,95~11℃),得到的有关生产数据统计如表1。并根据表中数据画出糖液在蒸发过程中色值的增加量(即蒸发糖浆色值与稀汁色值的差值)及菜… 相似文献
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讨论了在糖厂生产中,取消清汁加热对糖厂的汽耗、蒸发系统的汁汽温度的影响.详细地比较了取消二级加热、完全取消清汁加热和正常地进行清汁加热这三种情况下的蒸发系统有关运行参数的不同. 相似文献
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The clarified banana juice was subjected to different treatment namely bentonite, combination of gelatin and bentonite and control and stored at 4, 25 and 37 °C for 24 weeks. The effects of fining treatment, storage temperature and storage time on turbidity, total polyphenol, browning index, microbiological, and sensory quality of clarified banana juice were evaluated during storage. Fining treatment, storage temperature and storage time had a significant (p<0.001) effect on turbidity, total polyphenol and browning index of clarified banana juice. Turbidity and browning index of juice were reduced by fining treatment with bentonite and a combination of gelatin and bentonite but increased with storage temperature and storage time. A significant decrease in total polyphenol content and increase in turbidity and browning index were detected for all juice samples during storage. However, it was noted that changes were significantly greater in control juice stored at higher temperature than in juice stored at 4 or 25 °C for up to 6 months. Sensory evaluation revealed that juices treated with bentonite or a combination of gelatin and bentonite and stored at 4, 25 or 37 °C were acceptable for up to six months, whereas untreated juice stored at 37 °C was only acceptable for up to 16 weeks. 相似文献
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近红外光谱法测定清汁中还原糖含量 总被引:3,自引:0,他引:3
采用近红外光谱法测定清汁中还原糖含量,获得良好效果,所建模型标准误差小而决定系数高。数据采用修正的最小二乘法(MPLS)进行计算,所得多元回归线性方程的定标决定系数R2、交互定标标准误差(SECV)、交互定标决定系数(1-VR)分别为0.952,0.067,0.813,具有较好的相关性。用36个随机清汁样品检验该模型,近红外法预测结果与传统滴定法测定结果的检验工作标准误差(SEP)为0.070,检验决定系数为0.876,证明测定所建近红外法定标模型具有较好的稳定性。 相似文献
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为得到澄清的甘蔗汁,提高甘蔗汁的利用价值。考查了反应时间、两性聚丙烯酰胺的用量、反应温度和甘蔗汁的p H对甘蔗汁透光率的影响,在单因素基础上,利用L16(45)正交实验研究了最优组合和因素的主次关系,比较了原甘蔗汁与澄清后甘蔗汁的主要理化指标,并利用红外光谱和紫外光谱进行了表征。结果表明甘蔗汁澄清的最优组合:反应时间为20 min、絮凝剂用量为8 m L、反应温度为60℃和p H为5,因素的主次关系依次为p H、絮凝剂用量、反应温度和反应时间。在此条件下澄清后甘蔗汁透光率可达到94.7%。经澄清后的甘蔗汁较原甘蔗汁的VC、可溶性固形物、总糖和蛋白质等的含量有所下降,并且还有一定量的两性聚丙烯胺残留在甘蔗汁中。 相似文献
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Microfiltration (MF) is classified as a non-thermal process for the fruit juice industry. It could provide a better preservation of the phytochemical property and flavor of the juice. This work aimed to study the stability of phytochemical properties including vitamin C, total phenolic content, antioxidant capacity (2-Diphenly-1-picrylhydrazyl: DPPH, free radical scavenging capacity and Oxygen Radical Absorbance Capacity: ORAC assays), microbial and chemical–physical (color, browning index, pH and total soluble solid) properties of MF-clarified pineapple juice during storage at various temperatures (i.e. 4, 27, and 37 °C). The juices were clarified by microfiltration using hollow fiber module. The results showed that most of the phytochemical properties and soluble components were retained in the juice after microfiltration. No microbial growth was detected after 6 months of storage. The storage time and temperature did not affect total soluble solids and pH (P > 0.05). The color (L*) of clarified juice stored at 4 °C was lighter than the juices stored at higher temperature levels (P < 0.05). The phytochemical properties and total phenol content of the juice significantly decreased as storage time and temperature increased (P < 0.05). Vitamin C content was the attribute that affected storage time and temperature most as indicated by reaction rate constant and activated energy. Storage of non-thermally pasteurized and clarified pineapple juice at 4 °C was the most suitable since it allowed the best quality preservation. 相似文献
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