The use of ultrasonics for nanoemulsion preparation

Oil-in-water emulsions are an important vehicles for the delivery of hydrophobic bioactive compounds into a range of food products. The preparation of very fine emulsions is of increasing interest to the beverage industry, as novel ingredients can be added with negligible impact to solution clarity. In the present study, both a batch and focused flow-through ultrasonic cell were utilized for emulsification with ultrasonic power generation at 20–24 kHz. Emulsions with a mean droplet size as low as 135 ± 5 nm were achieved using a mixture of flaxseed oil and water in the presence of Tween 40 surfactant. Results are comparable to those for emulsions prepared with a microfluidizer operated at 100 MPa. The key to efficient ultrasonic emulsification is to determine an optimum ultrasonic energy intensity input for these systems, as excess energy input may lead to an increase in droplet size.Industrial relevanceThe preparation of oil-in-water emulsions is a common feature of food processing operations. The use of ultrasound for this purpose can be competitive or even superior in terms of droplet size and energy efficiency when compared to classical rotor­stator dispersion. It may also be more practicable with respect to production cost, equipment contamination and aseptic processing than a microfluidisation approach. The present paper shows that ultrasound can be effective in producing nanoemulsions for use in a range of food ingredients.     

酸水解麦麸蛋白质及氨基酸分析

探讨小麦麸蛋白的酸水解工艺。研究了盐酸浓度、料液质量体积比、水解时间对小麦麸蛋白水解度的影响,并对麦麸蛋白水解液的氨基酸组成进行了分析。在100℃,盐酸浓度4mol/L,料液质量体积比1∶6,水解时间18h的条件下麦麸蛋白的水解度为59.22%。氨基酸分析结果表明,呈甜味和鲜味的氨基酸总和达到53.77%。通过酸水解麦麸蛋白,可获得呈鲜味和甜味氨基酸含量较高的蛋白水解液,为麦麸蛋白水解液的生产提供理论参数。     

Size reduction of raw material powder: The key factor to affect the properties of wasabi (Eutrema yunnanense) paste

Wasabi paste is very popular worldwide because of its unique aroma and taste, which is produced from wasabi powder. In the present work, wasabi was ball-milled for 10, 20, 30, 40 and 50 min to obtain different particle size of powder, and the influence of ball milling time on the quality of wasabi paste was investigated. The product quality attributes such as color, water and isothiocyanate contents, chlorophyll content, rheology properties, flavor and sensory values were determined. Results shown that the best wasabi paste could be produced by ball-milling wasabi for 30 min yielding a particle size of 499.1 ± 36.1 nm, with the highest isothiocyanate, chlorophyll content and sensory scores as well as the best color properties. This work demonstrated that high quality wasabi paste could be produced by selecting proper ball milling time of the raw wasabi material to get proper particle size.     

青梅酒香气成分GC-MS分析以及降酸处理

采用顶空固相微萃取(HS-SPME)方法提取、富集浸泡青梅酒的香气成分,通过GC-MS检测,共鉴定出44种风味物质,含量占挥发性成分的99.34%,其中酯类22种,醇类11种,酸类2种,醛酮类6种,烃类1种以及其他化合物2种,这些物质构成了青梅酒的特征风味。针对浸泡青梅酒酸度过高的问题,试验研究了5种离子交换树脂对青梅酒的降酸处理,结果表明弱碱性大孔阴离子交换树脂D314呈现出良好的降酸效果。     

谈建筑工程施工安全问题及对策

随着我国城镇化进程的不断推进,全国的建设规模逐年高速增长,作为国民经济的支柱产业之一的建筑业,系一个危险性高、易发生事故的行业,安全生产事故频繁发生。安全生产是全社会高度关注的焦点,如何确保施工安全已成为全社会关注的热点话题。论文从施工安全的角度出发,分析我国建筑工程施工过程中存在的问题,并针对这些问题提出解决对策,以提高建筑施工安全管理水平,确保施工安全。     

基于香兰素的UV抗菌油墨的研制

目的 研制一种抗菌性优良的UV油墨,提升其应用价值.方法 在超声波的辅助下,萃取香草兰豆荚的主要成分.通过FT-IR和NMR对提取物进行表征,证实提取物为香兰素,产率为18.35％,相对质量分数为33.24％.以制备的香兰素为抗菌添加剂,设计油墨配方,并研制UV抗菌油墨,测试油墨的粘度、细度、流平性、固化速率,以及干燥后墨膜的耐醇性、柔韧性、硬度和抗菌性.结果 当香兰素的质量分数为5.0％(相对于油墨总质量)时,可制备粘度为4.07 Pa·s,细度为5μm,流平性良好、固化速率为150 m/min的UV抗菌油墨.将制备的UV抗菌油墨辊涂于集成天花板上并干燥成膜后,墨膜的耐醇性为5级,经过180°对折5次后无明显折痕,硬度为2H.抗菌性检测发现,墨膜对大肠杆菌的抑菌圈直径为21 mm,抑菌效率为99.20％,而对金黄色葡萄球菌的抑菌圈直径高达23 mm,抑菌效率也高达99.26％.结论 所研制抗菌油墨,可在保持良好印刷适性的同时,赋予油墨优良的抗菌能力.     

Influence of low-temperature ball milling time on physicochemical properties,flavor, bioactive compounds contents and antioxidant activity of horseradish powder

Horseradish is widely used as a seasoning and food additive due to its unique flavor and ability to act as antioxidant, among other favorable characteristics. A dried powdery form of horseradish is desired as it is convenient for either domestic or industrial use. Size reduction time is among the most important parameters that needs to be optimized to produce horseradish powder of higher quality. In this study, dried horseradish was milled either for 15, 30, 60, 120 or 180 min using a low-temperature ball-milling pulverizer to obtain powder of different sizes. Effect of milling time on particle size, microstructure, color, water and oil holding capacities, flavor profiles, isothiocyanates, phenolics and flavonoids contents as well as radical scavenging activities of the powder was determined. Powder milled for 60 min exhibited a more intense pungent flavor, better physicochemical properties and higher flavonoids content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity and 2,2′-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) free radical scavenging activity than the powder milled for different other periods of time.     

多种酶复合制备鸡皮胶原蛋白短肽

以鸡皮为原料,采用酶法提取胶原蛋白肽。研究了酶的种类、加酶量、酶解时间、酶解温度以及pH值对水解度和多肽质量浓度的影响,采用正交实验对酶解条件进行了优化。结果表明,当采用木瓜蛋白酶+胰蛋白酶+风味蛋白酶复合水解,加酶量为0.9%、酶解时间3 h、酶解温度45℃及pH为7时,为酶解最佳条件。     

酶解鸡骨架制备热反应底物的研究

鸡骨中含有丰富的营养物质,对鸡骨进行深加工,能有效提高蛋白质的综合利用率。作者通过比较采用Flavourzyme与Protamex以2∶1复配对鸡骨进行水解。以水解度(DH)为特征指标,对酶解鸡骨架的工艺进行优化,结果表明,最佳的工艺参数为:温度55℃,pH 6.5,时间5 h,酶用量为质量分数0.8%,料液质量比为1 g∶2 mL,在此条件下水解度为23.69%。所得酶解液用于对不同水解度的蛋白质酶解液对美拉德反应的影响进行分析。