共查询到19条相似文献，搜索用时 234 毫秒
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甘薯果脯普遍存在着外观色泽差和和口感差的质量问题。通过单因素和正交试验，探索甘薯果脯加工中的盐酸处理，硬化处理，硫处理及柠檬酸调整糖液，ｐＨ值等处理对产品外观色泽和口感的影响。 相似文献
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柠檬酸铁铵分光光度法测定茶多酚 总被引：1，自引：0，他引：1
利用茶多酚与柠檬酸铁铵生成深红色络合物进行分光光度法测定茶多酚。结果表明:在pH>10的碱性介质中络合物的最大吸收峰在550nm处,比色液茶多酚浓度在0～200μg/ml范围内遵从朗伯——比耳(Lambert-Beer)定律。考察了氨试剂、柠糠酸铁铵、羧甲基纤维素钠试剂对测定结果的影响,呈色物质的时间稳定性结果表明:茶汤待测液茶多酚浓度为2.4mg/ml时最适测定条件,低粘度羧甲基纤维素钠试剂用量5ml,柠檬酸铁铵试剂0.5ml,氨试剂0.5ml,蒸馏水定容至25ml,回收率98.3％～101.8％。本方法的缺点主要是低粘度羧甲基纤维素钠试剂需大、中型离心机离心,粘度大,如果没有压吸式移液管,移液较困难。 相似文献
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为研究不同加工方式对芒果干制过程中保鲜类农药残留量的影响,以芒果干的加工过程为例,研究清洗、去皮、护色、硬化、热烫及干燥等各个加工环节对芒果中常用保鲜类农药咪鲜胺、多菌灵、甲基硫菌灵及代谢物2-氨基苯并咪唑残留量变化规律的影响。结果表明:在芒果干制的过程中,随着加工环节的增加,芒果中常用保鲜类农药总体呈逐渐下降的趋势;去皮对咪鲜胺的影响最大,降解率达94.82%;干燥脱水的过程使得芒果干中4种农药的残留量增加,与真空干燥相比,恒温干燥箱干燥可以较大程度的去除芒果干制过程中的大部分农药残留,农药去除效果较好。 相似文献
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本文将在使用计算机技术与设施,采用L处理方法、计算机量化、图像处理等方式来进行对茶鲜叶的色坚定,与研究茶叶在加工过程中色泽的变化,茶鲜叶色泽及其嫩度,读取茶色泽参数进行茶叶识别等方面针对茶叶的品种,加工,品质等方面的应用进行思路分析。 相似文献
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研究柠檬酸处理对鲜切粉葛护色效果的影响,将鲜切粉葛分别放入0.5%、1.0%、1.5%柠檬酸溶液浸泡15 min后沥干,放置塑料托盘中,用聚乙烯保鲜膜包装后置于5℃恒温恒湿箱中贮藏,定期取样测定相关生理指标。结果表明,不同浓度柠檬酸处理能有效减轻鲜切粉葛的褐变程度,以0.5%柠檬酸处理效果较好,能显著降低PAL活性和总酚含量,抑制PPO和POD活性,减少丙二醛积累,保持较低的LOX活性,从而延缓鲜切粉葛的褐变,同时提高了总黄酮含量,减少淀粉、可溶性蛋白等营养物质的损失,有助于保持粉葛的良好品质。适宜浓度柠檬酸预处理可显著减轻鲜切粉葛褐变程度,维持较好的营养品质。研究结果为鲜切粉葛护色工艺提供参考。 相似文献
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茶叶色泽研究概况及其前景 总被引：4，自引：1，他引：4
茶叶色泽是指茶叶在自然状态下所表现出来的颜色状况。对茶叶色泽的研究主要集中在茶叶色泽与品质的关系、茶叶色泽的形成与改善、茶叶色泽的鉴别与利用等方面。1茶叶色泽与品质的关系茶叶色泽与茶叶品质关系密切,在一定程度上可以反映茶叶的品质状况。1.1茶叶色泽是茶叶品质的重要组成部分茶叶色泽是茶叶“色、香、味、形”诸要素的综合反映⑴。这里的“色”就是指茶叶色泽,既反映茶叶的颜色又反映其光泽性。在茶叶感官品质评定中,干茶色泽、汤色、叶底在茶叶感官品质八项因子中占了三项,并依据成品茶色泽将茶叶分为绿茶、红茶、青茶(乌龙… 相似文献
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红茶加工中有机酸代谢及对茶叶香气形成的影响 总被引：1，自引：0，他引：1
现已研究表明,红茶香气的形成可能途径主要有:醇类的氧化,氨基酸的降解,醇、酸类的酯化,羟基酸的脱水,类胡萝卜素的降解,芳香物质的异构化作用,脂肪酸的转化,糖及其与氨基酸的热化反应等。但是,在红茶加工过程中,产生多种有机酸,这些有机酸不仅参与了红茶滋味和色泽的形成,而且对其香气转化与发挥也起着重要作用。 相似文献
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本研究以山药零余子和玉米种子为受体材料,采用生物测试方法,以发芽率、发芽势、发芽指数、根长、茎长和干重为种子萌发和幼苗生长参数,研究山药植株腐解液、根系分泌物和根际土浸提液对受体材料的化感效应,旨在探明山药化感物质的释放途径,探索山药化感物质对不同受体材料的化感作用,为揭示山药连作障碍的机理奠定基础。结果表明：山药植株腐解液和根系分泌物对山药和玉米均有强烈的化感抑制作用,根际土浸提液的化感作用较微弱,化感作用强度为根系分泌物˃植株腐解液˃根际土浸提液,山药根系分泌物和植株腐解液含有丰富的化感物质,可能是山药自毒物质的主要来源之一,是山药化感物质研究的可靠基础材料;在试验设置的浓度范围内,山药化感物质对受体材料的抑制作用与其质量浓度呈正比,3种浸提液对受试材料的化感作用存在低促高抑的浓度效应,低于100 mg/mL时有微弱的促进作用,大于等于100 mg/mL就会产生强烈的抑制作用,随着浓度升高,化感抑制作用强度越大;山药的化感物质对玉米幼苗生长抑制强度大于种子萌发期,山药则相反;结合种子萌发和幼苗生长的综合化感效应指数,2种受试作物对山药化感作用的敏感程度为自毒作用强于他感作用。 相似文献
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《Plant Production Science》2013,16(2):181-185
AbstractFive gibberellins in the early-13-hydroxylation pathway (GA53, GA44, GA19, GA20 and GA1), and six gibberellins in the non-13-hydroxylation pathway (GA12, GA15, GA24, GA9, GA36 and GA4), were detected in the bulbils of Chinese yam. This indicated the presence of two gibberellin biosynthetic pathways in bulbils. The total endogenous gibberellins were dramatically increased in enlarged bulbils. The endogenous level of bioactive GA4 was always higher than that of GA1. A rapid increase in endogenous gibberellins including bioactive GA4 was observed during a 30-day storage period. These results show that gibberellins are closely related to bulbil enlargement and dormancy in Chinese yam plants. However, further research is needed for better understanding of the fluctuation of gibberellin levels in bulbils of Chinese yam during storage. 相似文献
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为了最大程度降低豆浆中抗营养因子含量的同时保证品质优良,以干豆制浆为对照,利用不同浸泡介质(水、柠檬酸溶液、NaHCO_3溶液)及不同浸泡条件,探究前处理工艺条件以及介质的改变对豆浆中抗营养因子及营养品质的影响。结果表明:浸泡处理能有效降低豆浆中胰蛋白酶抑制因子活性和植酸含量,但不同介质对不同抗营养因子的效果不同。经浸泡处理后的胰蛋白抑制因子的最低活性为30.88±1.35 TIU·mg-1,相对于未处理组降低了54%;植酸最低含量为3.46±0.15 mg·mL-1,相对于未处理组降低了77.4%;而经浸泡处理后的单宁含量却显著上升(P<0.05)。从降低胰蛋白酶抑制因子活性的效果来看,NaHCO_3>水>柠檬酸;从降低单宁含量的效果来看,柠檬酸>NaHCO_3>水;从降低植酸含量的效果来看,柠檬酸>水>NaHCO_3。除抗营养因子外,豆浆的品质指标也发生了显著变化,NaHCO_3浸泡组的总体品质最优,除了个别品质指标(蛋白质含量)与水浸泡组相比差异不显著(P>0.05),其它品质成分含量均显著高于水浸泡组,而柠檬酸浸泡组的品质为3组中最差。选取NaHCO_3溶液作为浸泡介质进行正交工艺优化,当浸泡温度为25℃,浸泡时间为16 h,浸泡豆水比为1∶4,NaHCO_3浓度为0.45%时,豆浆的抗营养因子的去除效果最好,品质最优。 相似文献
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Mestres C Dorthe S Akissoé N Hounhouigan JD 《Plant foods for human nutrition (Dordrecht, Netherlands)》2004,59(3):93-99
Color and taste are permanent features of amala, a traditional thick paste obtained from yam chips flour. To assess these attributes, 23 yam chips presenting various quality attributes were processed. The sensory attributes of their derived amala were determined and some biochemical characteristics of yam flours measured. A panel defined five main taste attributes for amala: sweetness, bitterness, acidity, fermented, and roasted tastes. Amala color was measured instrumentally and sensory scores were highly correlated with flour biochemical analyses; amala sweetness was positively correlated with glucose and fructose content of the flour, whereas amala acidity and fermented taste were linked to organic acids and lactic acid contents of flour, respectively. In addition, darkness, bitterness, and roasted tastes of amala could be tightly predicted by multiple regression analysis from phenolic compound and glucose–fructose contents. Phenolic content of yam flour plays thus a key role on sensorial quality of amala. However, polyphenol oxidase and peroxidase activities were almost null in yam flours and their specific role on yam flour phenolic content needs to be clarified. 相似文献
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福建山药地方资源主要农艺性状与品质特性比较 总被引：1，自引：0，他引：1
为了筛选出福建山药优良种质资源,为选育高产、优质的山药品种奠定基础,对收集自福建的24份山药农家品种的主要农艺性状与品质特性进行分析。结果表明,永定薯、MYSY1长势较旺,有不规则、较大零余子,且产量最高。漳州直薯、漳州块薯和松溪薯长势旺,无零余子;漳州直薯和块薯产量较高,但口感一般;松溪薯产量较高,但肉质疏松、含水量高、易氧化,口感较差,烘干后黑褐色。明溪薯、MSSY资源和清流薯长势中,无零余子,采收期长,含水量较少,肉质紧密,断面白而粘液多,口感好,烘干后颜色较白;永安薯长势中,无零余子,含水量少,淀粉和冷浸出物含量较高,烘干后色泽好,但其肉质结实,口感欠佳,且茎块小产量低;JYSY2、JYSY10和JYSY12资源长势弱,有少量零余子。安溪薯、松溪薯及漳州块薯的块茎形状为块状,其它资源的为长圆柱形、圆柱形。经聚类分析将24个品种分成了3组。综合评价,MSSY资源、MYSY1资源、明溪薯和清流薯具有较好农艺性状和品质特性,开发潜力巨大。 相似文献
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Naoto Hashimoto Takahiro Noda Sun-Ju Kim Md Zaidul Islam Sarker Hiroaki Yamauchi Shigenobu Takigawa Chie Matsuura-Endo Tatsuro Suzuki Kyu-Ho Han Michihiro Fukushima 《Plant foods for human nutrition (Dordrecht, Netherlands)》2009,64(3):193-198
To investigate whether yam improves glucose metabolism, yam-containing diets were given to Wistar rats. In a short-term experiment,
fasted-rats were given 1.0 g of a control and 20% yam-containing diets. At 60 min after start of the feeding, glucose level
in the yam diet group was lower or tended to be lower than that in the control diet. Insulin levels at 30 min and 60 min were
significantly lower than those in the control group. In a long-term experiment, a normal diet (N) or 25% high fat diets with
(Y) or without 15% yam powder (HF) were given to rats for 4 weeks. At 4 weeks, in an oral glucose tolerance test, the area
under the curve (AUC) of plasma glucose level was higher in the HF group than that in the N group, whereas those in the Y
groups did not differ from that in the N group. Glycosylated hemoglobin levels had similar tendency to the AUCs. Plasma leptin
levels in the Y groups were significantly higher than that in the N group. In conclusion, yam may contribute to improvement
of glucose metabolism. Additionally, we speculated that leptin level is possibly involved in the insulin-response to yam diets. 相似文献
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V. H. Mulimani D. Supriya 《Plant foods for human nutrition (Dordrecht, Netherlands)》1994,46(3):195-200
Some simple treatments were employed to reduce the tannin content in locally consumed sorghum grain. The treatments included overnight soaking of sorghum in 2% NaHCO3, soaking in different alkalis, ammoniation and autoclaving. Of the above treatments, ammoniation was best for complete removal of tannins. Soaking the seeds in alkalis was also effective. Soaking the sorghum seeds for 18 hours in mixed salt solution (containing 1.5% NaHCO3+0.5% Na2CO3 and 0.75% citric acid in w/v ratio) was also found to be effective. 相似文献
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《Plant Production Science》2013,16(3):393-397
The mechanism of gravitropism in yam tubers was investigated using two cultivars of Chinese yam, cv. Nagaimo which elongates to form a long tuber, and cv. Genkotsujirou which elongates in the initial stage and then spherically thickens. In both cultivars, many amyloplasts were locally formed and settled down vertically in each cell at the part beneath the stele of the elongating tuber. In contrast, amyloplasts in the stele in the apical part of the elongating tuber in these cultivars were smaller in number and size than those in the part beneath the stele and did not settle down vertically. In the thickening tuber of Genkotsujirou, the number of amyloplasts decreased and they did not settled down vertically in the part beneath the stele. In Nagaimo tuber tilted on an inclined plate, amyloplasts in the part beneath the stele in apical part of tuber also settled in the direction of gravity. Tubers elongated vertically as soon as they passed through the inclined plate. In such tubers, amyloplasts in the part beneath the stele were vertically settled down. These results indicated that amyloplasts in the part beneath the stele would play a role as statoliths for the perception of gravity. Crystal cells and tannin cells dispersed in the part beneath the stele of tuber as in the cortex surrounding the stele. The result indicated that the part beneath the stele is a part of cortex. Therefore, the cortex in the apical part of tuber was presumably important as the site of gravity perception. 相似文献