Principles of electrospraying: A new approach in protection of bioactive compounds in foods

ABSTRACT

Electrospraying is a potential answer to the demands of nanoparticle fabrication such as scalability, reproducibility, and effective encapsulation in food nanotechnology. Electrospraying (and the related process of electrospinning) both show promise as a novel delivery vehicle for supplementary food compounds since the process can be carried out from an aqueous solution, at room temperature and without coagulation chemistry to produce matrices or particulates in the micro- and nano-range. The presentation of core materials at the nanoscale improves target ability to specific areas of the digestive tract and gives improved control of release rate. Adoption of these electrohydrodynamic atomization technologies will allow the industry to develop a wide range of novel high added value functional foods. To optimize production conditions and maximize throughput, a clear understanding of the mechanism of electrospraying is essential. This article presents a comprehensive review of the principles of electrospraying to produce nanoparticles suitable for food technology application, particularly for use in encapsulation and as nanocarriers.     

马口铁三片罐内涂层质量与其导电值关系的探讨

马口铁食品罐内涂层质量的好坏直接影响内装食品的质量，用测量空罐导电值和反导电现象来判定，是控制内涂层质量的一个有效检验方法。     

Electrospraying of water in oil emulsions for thin film coating

Electrospraying of water-in-oil emulsions was investigated to produce thin edible barriers. A reproducible model surface was used, namely cellulose membranes of which permeability is well-established. PGPR-based emulsions were stable during electrospraying and produced a fine stable jet spray; emulsions prepared with lecithin and span80 produced unstable jets and only sporadic sprays. The droplet size decreased to 50 ± 10 μm by the addition of water droplets till 3% but remained constant at higher water volume fractions. On the other hand, the addition of protein and salt influenced the droplet size and radius values up to 200 μm were found. The addition of whey protein isolate (10% w/w) resulted in films with water vapour barrier properties that were at least 70% better than lipid only, therewith showing that addition of protein enhances the integrity of the films.     

A statistical study on selected process parameters of electrospraying

Deposition time is a key factor in determining application ease, time, and cost of electrospraying. This statistical study investigates the contribution of process parameters of electrospraying on deposition time when conducted for the application of commercially available fluoropolymer resin onto cotton fabric. The results showed that solution viscosity was highly significant on deposition time, and any variation in other parameters would cause highly significant changes in deposition time for the solutions with a higher viscosity/fluoropolymer resin concentration.     

涂膜保鲜在袖珍黄瓜中的应用

选用海藻酸钠、明胶、壳聚糖、硬脂酸等原料作为涂膜原料对袖珍黄瓜进行涂膜处理,分别对袖珍黄瓜的失重率、呼吸强度、烂果率、叶绿素含量、硬度和可溶性固形物进行了测定。结果表明,第一层为海藻酸钠／明胶（1％/0．3％）第二层为硬脂酸／色拉油（1g：2mL）的两层膜的保鲜效果最好,能抑制袖珍黄瓜的呼吸作用,阻止可溶性固形物的分解。     

复合涂膜对室温条件下鲜食糯玉米保藏效果的影响研究

研究了壳聚糖、魔芋、植酸等涂膜对鲜食糯玉米保藏效果的影响。结果表明：涂膜保鲜糯玉米有一定的应用价值，3种涂膜均能够降低呼吸强度，减轻膜脂过氧化程度，减轻失重率，阻抑可溶性糖向淀粉转化，降低水分散失，3种涂膜中壳聚糖复合涂膜和植酸复合涂膜表现了较好的保鲜效果。     

Investigation of different coating application methods on the performance of edible coatings on Mozzarella cheese

The performance of edible coating is influenced by the properties of coating materials and execution methods. In this study, three different coating materials (chitosan, sodium alginate, and soy protein isolate) and four different coating application methods (dipping, enrobing, spraying and electrostatic spraying) were investigated on their performance for coating Mozzarella cheese. The properties of coating solutions, morphology and basic quality changes of the cheese during storage at 4 °C were evaluated. Results showed that sodium alginate solution was the most viscous (η = 0.155 Pa s) and had small contact angle on hydrophobic substrate surface indicating its better spreadability on cheese. Film thickness displayed obvious differences based on the coating methods (ranging from 30.6 to 83.3 μm), with two spraying methods leading to thinner coatings. Sodium alginate coated cheese possessed the best overall physicochemical properties during storage whereas the preservation effects were not significantly different among four coating methods. This study provided valuable new information about the effective coating application methods for different coating materials.     

含茶多酚的壳聚糖涂膜对鸡蛋保鲜效果的影响

用茶多酚和壳聚糖制成的复合涂膜液对鸡蛋进行涂膜处理,以感官指标、失重率、蛋黄指数、蛋清pH值、哈夫单位为质量指标定期取样分析测定,研究所制成的涂膜液在室温条件下对鸡蛋的保鲜效果。结果表明,和对照相比,含茶多酚的壳聚糖涂膜液能较好地保持鸡蛋的新鲜度和品质,尤其以1.5%的壳聚糖溶液联合200mg/kg茶多酚制得的涂膜液保鲜效果最好,经此涂膜液处理后的鸡蛋室温下贮存35d,失重率为1.89%,蛋黄指数为0.26,哈夫单位为60.109,蛋清pH值为8.20。     

The potential allergenicity of novel foods

Recombinant DNA technology provides a powerful tool to create new products in many different fields. Agriculture and the agro-food industry are two of them. Genetic engineering aims at improving the yield, the nutritional quality or the technological value of food crops. The composition of foods may also be modified in order to decrease the content of toxic substances sometimes present in certain food crops. The expression of recombinant proteins in foods must be carefully assessed as proteins may induce allergic reactions in humans. Currently, the potential allergenicity of a protein can be reasonably assessed only when the protein is known to trigger an immune response in sensitive subjects. By contrast, the potential allergenicity of a protein of unknown allergenicity cannot be easily predicted as no immunoserum of allergic subjects is available. That is why an allergenicity assessment model for any genetically engineered food should be designed. Even though the gene product is completely characterised in the transgenic product, this does not necessarily provide information on its potential allergenicity. Animal models, in vitro tests and protein structure should be taken into account. Besides, allergenicity is a biosafety issue, for it deals with human health. The issue of food allergies in food safety should not be neglected, as an allergic reaction can be life threatening. ©1997 SCI     

豇豆涂膜保鲜效果的研究

目的分析大豆分离蛋白与茶多酚对豇豆进行涂膜保鲜的可行性。方法用茶多酚和大豆分离蛋白复合涂膜液处理豇豆,测定低温(7℃)贮藏过程中呼吸强度、细胞膜相对透性、失重率、叶绿素含量、纤维素含量和维生素C含量等各项指标的变化。结果涂膜处理可明显降低豇豆的呼吸速率和失重率,减缓了贮藏期间豇豆维生素C与叶绿素含量的下降,对豇豆的纤维化及细胞膜相对透性的上升有明显的抑制作用,且成膜剂大豆分离蛋白中添加茶多酚可进一步增强涂膜处理的效果,和对照相比,5%的大豆分离蛋白溶液中添加200mg/kg茶多酚制得的涂膜液处理样品可将豇豆的低温保鲜期从6 d延长至12 d。效果显著。结论大豆分离蛋白中添加茶多酚能够明显延长豇豆的保鲜期。     

涂膜保鲜对不同蛋龄鸡蛋贮藏品质的影响

选用0,3,6,10 d蛋龄鸡蛋,经涂膜处理,对比不同蛋龄组贮藏品质的变化.结果表明：各组鸡蛋失重率差异不显著（P＞0.05）;蛋黄系数差异显著（P＜0.05）;蛋白系数和蛋白pH值差异极显著（P＜0.01）.贮存60,0 d蛋龄全部为新鲜蛋,失重率1.95%,蛋黄系数为0.32,蛋白系数为0.61,蛋白pH值仅为8.79;3 d蛋龄次鲜蛋占84%,散黄蛋占16%;6 d蛋龄次鲜蛋占50%,散黄蛋占50%;10 d蛋龄全部散黄.     

饮料成分对两片罐内涂膜导电值的影响

文中较系统地研究了饮料内容物中各类食品添加剂，如食用酸、甜味剂、防腐剂和调味剂等对两片罐储存性能（罐导电值）的影响。为了减缓饮料对罐体的腐蚀，比较了多种络合剂、植物抽提物和缓蚀添加剂等在降低导电值方面的效果。并且较系统地分析了导致两片罐渗漏的原因，提出了避免两片罐渗漏的综合意见。     

The potential effects of demands for natural and safe foods on global food security

There are a number of intersecting and conflicting issues that may require greater oversight than is currently evident:

1. Global food security as defined by FAO, requires that all people have access to adequate supplies of safe, nutritious food of their own choice for healthy living. There is evidence that such amounts of suitable food are being produced in the world today, but not available to all (FAO, 2006).

2. Demands for natural and safe foods and ingredients are expanding and people in the new and developed countries can afford to pay premium prices.

3. Relatively inexpensive air freight allows rapid deliveries of “fresh” and minimally processed food items along extensive supply chains. There are no calculations of environmental costs in evidence.

4. Minimum food processing is demanded, placing a heavy reliance on local safety standards at point of origin and in transit. This can and has created conflict of priorities between improving local safety standards and maintaining profitability. Recent events in China are an important case study.

5. Risks to consumers can escalate as increasing sales demand an expanding range of suppliers and a sometimes expanding supply chain. Failure of any one link can be critical for the chain and its end-user.

6. Opportunities for international suppliers and demands on the production potential of many developing countries can reduce the availability of basic foods to local markets.

7. A new phenomenon has arisen of obesity and starvation occurring simultaneously in the same country (The Australian, 2007), an example of national wealth divergence.

Conclusions

Natural does not mean Safe, particularly with regard to food. Disturbing outcomes during interviews for a local television programme, Catalyst (www.abc.net.au/catalyst, 16 August, 2007), were the extent to which not only the members of the public, but also a General Medical Practitioner, interviewed believed that natural products must be safe. This is an ongoing concern for the food industry and others.Safe food is a term relative to local customs and standards and the further the foods travel from a culture, the greater the need for compliance with accepted international food safety and quality standards. Economic pressures are always likely to compromises in meeting stringent requirements.The demands and freedom of food choice emanating from the growing affluence of some can severely limit the possibilities of food security for others.The International Council for Science (ICSU, www.icsu.org) has a number of programmes in place looking at issues such as Global Environmental Change and Food Systems (GECAFS) and Health and Wellbeing in the Changing Urban Environment (SHWB). Both projects deserve attention.Ultimately, it will depend on each of us and our attitudes as consumers as to how a balance can be obtained between free choice and food security for all. Last month we reached the mid-term of the Millennium Development Goals to reduce the world's hunger by half. We have not met our targets so far and there are signs of harvest difficulties ahead. A more engaging strategy is needed with greater international cooperation. Are we up to the challenge?Free Trade, Fair Trade and Safe Trade are not, after all, equivalent.Food security “Food Security exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preference for an active and healthy life.”FAO, 1996.“All substances are poisons: there is none which is not a poison. The right dose differentiates a poison and a remedy.”Paracelsus, 1493–1541.World Food Summit (WFS) and Millennium Development Goals (MDGs) Despite disappointing performances in reducing the number of hungry people, a smaller percentage of the populations of developing countries is undernourished today compared with 1990–92: 17 percent against 20 percent. FAO's projections suggest that the proportion of hungry people in developing countries in 2015 could be about half of what it was in 1990–92: a drop from 20 to 10 percent.Thus the world is on a path to meeting the MDG 1 on hunger reduction but will miss the WFS target by 170 million people.FAO, 2006.

壳聚糖涂膜保鲜对芒果保鲜效果的研究

研究了以壳聚糖作为主要涂膜保鲜剂,辅之以有效的抑菌措施,通过实验得出最佳配方为1.5%壳聚糖、0.10%防腐剂、pH为5.45。结果表明,采用上述配方对芒果进行保鲜,可使芒果在常温(26～30℃)下稳定保存达18d以上,与对照组芒果比较失重率降低35.2%,好果率达100%,硬度提高13.7%,有效地达到了延长保质期、提高品质且易推广的目的。     

织物表面涂层沉积过程模拟

通过对大气压等离子体液相沉积工艺过程作用机制的研究,围绕如何提高液相沉积效率问题,构建了织物表面微观薄膜沉积过程动力学模型。探讨了放电功率、超声频率、处理时间、单体流速、氦气流速对薄膜沉积速率及膜层性能的影响,数值模拟涂层表面形态的变化,得出不同工艺参数下织物表面的沉积率变化规律,揭示薄膜沉积过程中聚合粒子的生长、涂层密度和质量的产生规律。这些结果对于预测成膜结构和优化具体等离子体液相沉积的工艺参数,提高沉积率和沉积薄膜的均匀度及对实际生产中如何提高材料的利用率和节约成本等方面具有一定的指导作用。     

转基因食品潜在致敏性评价方法的研究进展

随着转基因食品在人类消费生活中的应用日益增加,人们对于完善转基因食品潜在致敏性评价方法的需求也不断增强.本文就现有转基因食品潜在致敏性的评价方法,包括决策树、序列同源性、血清学筛选、消化稳定性(抗胃蛋白酶性)以及动物模型等的研究进展做一概述,对其现状做出总结并对其发展提出建议.     

基于灌装时间随机误差的灌装精度概率模型与可靠度计算模型

描述了灌装时间与灌装精度的关系，针对实际存在的各种随机变量对灌装时间的影响，建立了控制液定量长管式灌装机的灌装时间的概率计算模型。提出基于灌装时间随机误差的灌装精度及其可靠度概念，并相应建立出灌装精度概率模型与灌装精度可靠度计算模型。     

蔗糖基聚合物涂膜对樱桃番茄保鲜效果的研究

以不同浓度的蔗糖基聚合物溶液作为樱桃番茄的涂膜保鲜剂,研究其对樱桃番茄采后生理的影响。结果表明,蔗糖基聚合物涂膜能降低樱桃番茄的呼吸强度,抑制VC含量以及过氧化物酶和多聚半乳糖醛酸酶活性的升高。      

复配生物涂膜保鲜液对冷藏南美白对虾的保鲜效果研究

目的 探究复配生物涂膜保鲜液对冷藏南美白对虾的保鲜效果.方法 以新鲜南美白对虾为原料,通过单因素实验考察壳聚糖、海藻酸钠、明胶及乳酸链球菌素(Nisin)对冷藏南美白对虾货架期的作用.在此基础上优化壳聚糖、海藻酸钠及Nisin所组成的复配涂膜保鲜液的最适配比.结果 壳聚糖6 g/L、海藻酸钠8 g/L、Nisin 0....