浅谈硫酸不溶物在生产工艺上的产生

硫酸不溶物简单地说就是在强硫酸中不能溶解的那一部分物质，这些在棉短绒中通常指破籽、籽皮、叶屑、碎壳、泥沙和其它有机物质如半纤维素等。     

磷脂产品丙酮不溶物测定方法及其负偏差产生的原因

介绍了几种常见磷脂产品的质量指标和国内外对磷脂含量标志性指标——丙酮不溶物的检测方法,说明了用这些方法测定的结果都存在负偏差,分析了负偏差产生的原因,提出了减小负偏差的方法。     

一种降低辣椒红色素不溶物含量的方法

辣椒红色素是一种天然类胡萝卜素,色泽鲜艳,着色力强,安全无毒,广泛应用于食品、医药、化妆品等领域。目前辣椒红色素普遍存在不溶物、杂质含量高的问题,产品利用程度低,严重影响经济效益。本研究以辣椒红色素为原料,确定了一种辣椒红色素纯化的方法。其最佳脱胶剂添加量即加酸量为2.5g,加水量为40g,加盐量为3g;在此条件下处理的辣椒红色素不溶物可降低至0.38%。使用此方法处理得到的辣椒红素呈深红色,具有诱人的光泽,流动性好,品质高;并经过车间中试取得了良好的效果。     

降低成品糖水不溶物的措施

糖厂成品糖中的水不溶物，主要是来自制精设备和工艺管路中的氧化铁锈片和各种不溶性钙盐的积垢．它不但影响白糖的理化指标，而且增加糖中黑点数量，影响美感观指标．各制糖生产企业目前普遍采用板框压虑机过虑—砂煮糖用的糖浆．为保证过滤速度的需要，选用的滤布布纹间要求有适当的孔隙，而且过滤是在泵送糖浆的压力下进行，加之滤布过渡面常出现细小的破漏，这将不可避免地有一些细小的块状氧化铁和积垢进入成精结晶系统．实际生产中，为考虑综合经济效益，不可能频繁地更换新德布，一旦德布破损漏榨或过滤压力偏高，则过滤效果差，过驻…     

检测高纯度大豆磷脂乙醚不溶物含量方法研究

磷脂乙醚不溶物含量是影响浓缩磷脂品质一个重要因素,按目前通行行业检测法,其检测结果有时会与磷脂外观质量不符。该文介绍经改进后能适于检测高纯度浓缩磷脂乙醚不溶物含量方法。     

煤焦油甲苯不溶物测定方法的改进

通过实验数据和试验方法的比较,证明甲苯不溶物的测定方法可以利用水分测定进行改进,提高了甲苯不溶物测定的精密度和准确度。     

关于棉短绒硫酸不溶物检验的探讨

针对棉短绒硫酸不溶物检测,本文分析了取样过程、溶解过程及抽滤过程中存在的问题,提出相应的注意事项或解决方案。     

三种不同改性方法对甘薯渣不溶性膳食纤维改性效果的研究

该研究采用胶体磨湿法粉碎法、超声波辅助酸法、纤维素酶法3种方法处理甘薯渣不溶性膳食纤维(insoluble dietary fiber,IDF),比较改性前后IDF粒径分布、微观形态,并测定分析其理化性质.结果表明,与未改性甘薯渣IDF相比,3种改性方法改性之后,甘薯渣IDF的粒径、分散指数显著降低(P<0.01),持...     

发酵工艺条件对不溶性大豆膳食纤维得率的影响

以豆渣为原料,以保加利亚乳杆菌(Lb)和嗜热链球菌(St)为混合菌种,用发酵法制备不溶性膳食纤维(IDF)。通过发酵温度、初始pH值和接种比例等因素对不溶性膳食纤维得率的影响进行单因素试验和正交试验,确定最佳发酵工艺参数。结果表明,在豆渣∶水=1∶3(质量比)、白砂糖2%和接种量4%的条件下,当发酵温度42℃、初始pH值6.35、接种比例1∶1时,大豆不溶性膳食纤维的得率为83.27%。     

谷物不溶性膳食纤维改进的快速测定方法研究

为了解决谷物不溶性膳食纤维的测定方法中因淀粉含量高造成过滤困难的问题,对美国谷物化学家协会审批方法AACC方法32-20(1999)谷物不溶性膳食纤维测定方法进行了改进研究。改进后测定的谷物不溶性膳食纤维值与AACC方法32-20(1999)测定值基本一致,两种方法的精密度差异不显著,微晶纤维素回收率为97.75%。改进的快速测定方法的过滤时间(15min)比AACC方法缩短了65min,占AACC方法过滤时间(90min)的19%,缩短了81%。改进的快速测定方法酶解时间为1.5h,比AACC方法(酶解时间为18h)少了16.5h。     

Effect of different curd-washing methods on the insoluble Ca content and rheological properties of Colby cheese during ripening

A curd-washing step is used in the manufacture of Colby cheese to decrease the residual lactose content and, thereby, decrease the potential formation of excessive levels of lactic acid. The objective of this study was to investigate the effect of different washing methods on the Ca equilibrium and rheological properties of Colby cheese. Four different methods of curd-washing were performed. One method was batch washing (BW), where cold water (10°C) was added to the vat, with and without stirring, where curds were in contact with cold water for 5 min. The other method used was continuous washing (CW), with or without stirring, where curds were rinsed with continuously running cold water for approximately 7 min and water was allowed to drain immediately. Both methods used a similar volume of water. The manufacturing pH values were similar in all 4 treatments. The insoluble (INSOL) Ca content of cheese was measured by juice and acid-base titration methods and the rheological properties were measured by small amplitude oscillatory rheology. The levels of lactose in cheese at 1 d were significantly higher in CW cheese (0.06-0.11%) than in BW cheeses (∼0.02%). The levels of lactic acid at 2 and 12 wk were significantly higher in CW cheese than in BW cheeses. No differences in the total Ca content of cheeses were found. Cheese pH increased during ripening from approximately 5.1 to approximately 5.4. A decrease in INSOL Ca content of all cheeses during ripening occurred, although a steady increase in pH took place. The initial INSOL Ca content as a percent of total Ca in cheese ranged from 75 to 78% in all cheeses. The INSOL Ca content of cheese was significantly affected by washing method. Stirring during manufacturing did not have a significant effect on the INSOL Ca content of cheese during ripening. Batch-washed cheeses had significantly higher INSOL Ca contents than did CW cheeses during the first 4 wk of ripening. The maximum loss tangent values (meltability index) of CW cheese at 1 d and 1 wk were significantly higher compared with those of BW cheeses. In conclusion, different curd washing methods have a significant effect on the levels of lactose, lactic acid, meltability, and INSOL Ca content of Colby cheese during ripening.     

Solvent optimization extraction of antioxidants from foxtail millet species’ insoluble fibers and their free radical scavenging properties

In this study, water and 80% of four organic solvents were employed to optimize the extraction of antioxidants from two species of foxtail millet’s insoluble fibers under the same temperature, time, and solid/solvent ratio. The results showed that the acetone was able to extract the maximum amount of antioxidants (2.32 mg/g fiber for white specie and 3.86 mg/g fiber for yellow specie) followed by methanol and propanol from both samples. The neutral and the ethanol on the other hand extracted small amount of the antioxidants from the two fiber materials. While considerable level of Total Polyphenols Content (TPC) was recorded in both the water and the organic solvents’ extracts, only traces of Total Flavonoid content (TFC) were observed in water, methanol and ethanol extracts. Propanol and acetone extracts was negative to the TFC test.     

降低轧棉和纺纱工序中杂质的模块化解决方案

杂质分离器是一种有效的降低纤维杂质的工具。搭配几种灵敏感应器模块的系统能有效地检测和去除几类杂质。这样的系统也可成功地用于轧棉工序。     

Comparing profiles and antioxidant properties of soluble and insoluble phenolics in Perilla frutescens seed flour extracts obtained by different extraction/hydrolysis methods

Cold‐pressed Perilla frutescens seed flour (CP‐PFSF) is a potential source of natural antioxidants. In this study, different methods were used to extract both soluble and insoluble phenolics from CP‐PFSF. Also, the phenolic profiles and antioxidant properties were compared. Results showed that soluble phenolics could be extracted using aqueous‐organic solvents, where 80% acetone resulted in the highest extraction yield and antioxidant activities. Insoluble phenolics remaining in residues could be released by acid or alkaline hydrolysis, where acid hydrolysis provided higher yield and antioxidant activities than alkaline. Soluble and insoluble phenolics could be extracted simultaneously through acid/alkaline hydrolysis, resulting in nearly the same yields for total phenolics. However, the phenolic components and antioxidant activities of extracts varied significantly, depending on the methods. Principal component analysis and correlation analysis revealed that a strategy of 80% acetone with successive acid hydrolysis steps released more rosmarinic acid, which have high antioxidant activities.     

Roles of soluble and insoluble aggregates induced by soy protein processing in the gelation of myofibrillar protein

The role of soluble and insoluble aggregates induced by soy protein isolate (SPI) processing in the gelling properties of myofibrillar protein (MP) was studied. Incorporating soluble SPI aggregate could greatly improve (P < 0.05) the elastic modulus (G’) and water‐holding capacity (WHC) of MP gel, but had no notable effect on MP gel strength. In contrast, incorporating the insoluble SPI aggregate significantly enhanced the G’, strength and WHC of MP gel, although the improvement in WHC was smaller than that produced by the soluble aggregate. The results of environmental scanning electron microscopy showed that the soluble SPI aggregate induced a less randomly composite gel structure, which may explain its notable enhancement of WHC. However, the insoluble SPI aggregate appeared to be granules embedded in the continuous MP gel matrix, which may be related to the reinforcement of gel strength. Hence, the results of this study suggest further means of processing commercial SPI for use in meat products.     

Development and validation of analytical methods for monomeric and oligomeric migrants from nylon 12 packaging materials

Analytical methods for the determination of laurolactam--the monomer of nylon 12--as well as the cyclic dimer and trimer were established. High performance liquid chromatography using ultraviolet (HPLC-UV) and mass spectrometric detection (HPLC-MS) were both found suitable to identify and quantify monomer, cyclic dimer and trimer well below the specific migration limit (SML) of laurolactam, being 5 mg/kg of food (simulant). Gas chromatography with flame ionisation detection (GC-FID) showed to be an appropriate method for the detection of only laurolactam in aqueous and fatty food simulants. Food simulants could be analysed directly by all three methods, or after a change of solvents. For olive oil, a method for sample clean-up by size-exclusion chromatography (SEC) was established.     

仪器法测定羊毛条中异色纤维的样品制备方法比较

应用FibreGen检测系统对羊毛条中的异色纤维和植物性杂质含量进行测试,可客观快速地对异色纤维和植物性物质进行分类、检测,缩短了检测时间,提高了检测效率,避免了传统感官检验法人为因素的影响。探讨了不同溶剂或不同纤维网制备方法对测试结果的影响。试验结果表明:FZ/T 20033—2019《绵羊毛、山羊绒条中异色纤维和植物性杂质的测定》中采用的苯甲醇或肉桂酸乙酯和邻苯二甲酸二甲酯的混合物2种溶剂,以及拉伸法或梳理法2种纤维网制备方法,测试结果均不会产生显著差异。