Continuous in-line decontamination of food-processing surfaces using cold atmospheric pressure air plasma

This study assessed a continuous in-line decontamination system for food contact surfaces and processing equipment that utilized cold atmospheric pressure plasma (CAP) generated from ambient air. The plasma system was evaluated against two common foodborne pathogens (Salmonella Typhimurium, Listeria monocytogenes) on stainless steel surfaces and against S Typhimurium on commercial poly[ether]-thermoplastic poly[urethane] (PE-TPU) conveyor belts, under simulated conditions of a food-processing facility. A significant level of microbial inactivation was achieved, up to 3.03 ± 0.18 and 2.77 ± 0.71 logCFU/mL reductions of L. monocytogenes and S. Typhimurium respectively within 10 s total treatment on stainless steel surfaces, and a 2.56 ± 0.37 logCFU/mL reduction of S. Typhimurium within 4 s total treatment on the PE-TPU material, according to a procedure based on the well-established EN 13697:2015 industrial protocol. CAP exposure was shown to have a minor impact on the morphology and composition of the treated surfaces. The results indicated that CAP can be applied for effective and continuous disinfection against common foodborne pathogens in food-processing facilities.Industrial relevanceLow temperature plasmas have shown great promise for microbial decontamination, yet industrial uptake of the technology has been limited due to scaling limitations. In this study, a prototype conveyor-based CAP decontamination system was developed and tested under realistic conditions expected within a food-processing facility. The results showed a high level of antimicrobial action against two common foodborne pathogens within a few seconds of CAP exposure, a timescale in line with industrial line processing speeds. Our findings demonstrated that CAP shows great promise for the continuous in-situ decontamination of food contact surfaces, with the potential to mitigate against the costly downtimes incurred in current production line practices implementing chemical disinfectants.     

Effect of tea polyphenols on the physical and chemical characteristics of dried-seasoned squid (Dosidicus gigas) during storage

The effects of tea polyphenols (TP) dip treatment on the physical and chemical characteristics of dried-seasoned squid (Dosidicus gigas) during storage at 25 °C were assessed. After the storage, the b* value increased significantly, while the free amino acids (FAA) including Ser, Gly, Arg, Tyr and Lys, and the dominant reducing sugar (RS), lactose, decreased remarkably, which revealed the occurrence of browning reaction in dried-seasoned squid. The progressive conversion of trimethylamine oxide (TMAO) and production of thiobarbituric acid (TBA) and total volatile basic nitrogen (TVB-N) were found during the entire period of storage. Furthermore, the advantages of reducing moisture loss, inhibiting oxidation of lipids, depressing TMAO breakdown and TVB-N accumulation were observed, while the browning reaction exhibited no significant decrease for the TP samples. These results indicated that the addition of TP could maintain quality of dried-seasoned squid.     

3D printing and controlled release of functional ripening surimi improved by nano starch-xylo-oligosaccharides: Chemical bonds and microstructure influences

To solve the problem of fast release, unsustainability of functional compounds in 3D printed surimi, nano scale of rice starch-xylo-oligosaccharides (XOS) was prepared. Meanwhile, its characteristics and printing effects on surimi were determined. Results shown that the nano rice starch and XOS with ratio of 1:2.5 had good characteristics (particle size 444 nm, embedding rate 86%, stable particle size with Na⁺ and heating process). Moreover, it endowed surimi with antioxidant ability and prolonged the release of XOS in surimi during in vitro digestion, which might keep it for continuous release. Additionally, nano starch-XOS increased ionic bonds and hydrogen bonds by 78% and 58% respectively to enhance gel strength, texture of surimi. As well as it also could fill up gel network gaps to form denser structure, which increased self-supporting ability to improve printing effects. While excessive XOS (>1%) could wrap protein to inhibit gel formation to produce burs and pores of printed surimi-XOS, leading to the pores enlargement and collapse due to the enhancement of hydrophobic force and disulfide bonds after ripening. However, nano starch could aggregate XOS to delay the occurrence of collapse (>2% XOS content). Thus, nano starch-XOS could promote the application of functional surimi in 3D printing.     

The composition and properties of squid meat

Many European and American fisheries have recently started to exploit oceanic and inshore squid resources. There is thus a need for developing domestic markets for squid products. The yield of edible parts of squid is 60–80% of the total weight and the chemical composition of the meat is similar to that of lean fish. However, the structure of the muscles is different, being composed of several layers of fibres running transversally to each other and covered with several sheets of connective tissue. A characteristic feature of squid proteins is a high proteinase activity and high solubility of the myofibrillar proteins during exhaustive extraction with water. The cooking loss in squid is up to about 40%. The texture, which does not resemble that of cooked fish, and the juiciness of the squid mantle, can be controlled by the cooking time and by pretreatment in polyphosphate solutions.     

Effects of selected properties of ultrafiltered spray-dried milk powders on some properties of chocolate

The effects of selected properties of spray-dried milk fat powders on chocolate were determined. Milk powders produced from control or ultrafiltered (UF) milks with various levels of fat were blended with skim milk powder to give a standard 26 g fat 100 g⁻¹ powder. Particle size of the chocolate mixes after refining decreased as the fat content and free-fat content of the powders increased. Despite this, increasing fat and free-fat contents of powders reduced the Casson viscosity of the subsequent molten chocolates. Casson viscosities using powders from control or UF milks were similar, but decreased as the particle size of powders increased and particle size after refining the chocolate mix decreased. Casson yield value and hardness decreased as fat content of powders increased. Casson yield value increased with vacuole volume of powders. It is possible to alter important properties of chocolates using milk powders of varying fat contents, free-fat contents and particle sizes.     

鱼肉中盐酸小檗碱和盐酸氯苯胍残留的快速测定

传统的固相萃取和过膜技术存在操作繁琐、耗时长等问题。本文通过优化相关技术参数,整合通过式固相萃取(PRiME)和微孔滤膜技术,实现进样前操作步骤一体化。利用液相色谱串联质谱建立鱼肉中盐酸小檗碱和盐酸氯苯胍的定量检测方法。方法验证试验结果显示:盐酸小檗碱和盐酸氯苯胍在质量浓度0.5~100μg/L范围内线性关系良好,检出限(LOD)分别是0.51μg/kg和0.53μg/kg,定量限(LOQ)分别是1.67μg/kg和1.68μg/kg,日内精密度相对标准偏差范围分别为4.09%~4.48%和3.84%~3.90%,日间精密度相对标准偏差范围为5.17%~5.73%和4.23%~5.29%。在5,10,50μg/kg 3个水平下,盐酸小檗碱和盐酸氯苯胍的回收率范围分别为91.2%~93.2%和91.3%~92.4%;RSD范围分别为4.5%~4.6%和1.8%~5.2%。采用液相色谱串联质谱法测定市售活鱼中目标化合物残留,未检出阳性样品,说明盐酸小檗碱和盐酸氯苯胍在水产养殖方面使用情况良好,该检测方法符合痕量分析的要求。     

X-ray irradiation - nonthermal processing and preservation of fresh winter jujube (Zizyphus jujuba mill. cv. Dalidongzao)

In this research, winter jujubes were treated with X-ray doses of 0, 0.3, 0.5 kGy and stored at 0 °C. Then jujubes from early (day 0) and late (day 60) storage were transferred to 20 ± 1 °C and qualities were evaluated every 3 days to explore the preservation effect of X-ray. Results indicated that 0.3 kGy X-ray inhibited the jujube decay by preventing 8.20% of fungal and 29.12% of aerobic bacterial growth. The pectin decomposition was prevented (0.21% on day 60), softening was alleviated, and reddening was delayed for 5 days correspondingly. Microscopic observation validated the integrity of the treated jujube tissue. Furthermore, the highest inhibition rates of 0.3 kGy X-ray on the activities of polygalacturonase (PG), cellulase and β-glucosidase (β-Glu) were 47.32%, 74.71% and 68.00%, respectively. Research demonstrated X-ray's potential in winter jujube preservation, which can provide a solid theoretical reference for the development and industrial application.     

Advance in food-derived phospholipids: Sources,molecular species and structure as well as their biological activities

BackgroundPhospholipids derived from different food sources have been extensively studied and widely used in different industrial areas, including food, animal feed, medicine, and pharmaceuticals. In recent years, the utilization of phospholipids, particularly bioactive ones, has gained attention, owing to their enrichment of n-3 polyunsaturated fatty acids.Scope and approachThis article presents a detailed and up-to-date review on the sources, molecular species, and structures of food-derived phospholipids. Moreover, this review highlights the structure–activity relationship of phospholipids and provides mechanistic insights into their biological activities.Key findings and conclusionsFood-derived phospholipids have been isolated and characterized from various sources, including plant, animal, and aquatic sources. These phospholipids possess considerable differentiation in their molecular species and structure, owing to variations in the properties of the polar headgroup, the length of the fatty alkyl chain, and the degree of unsaturation. In particular, the molecular species of aquatic-source phospholipids show a substantial amount of n-3 polyunsaturated fatty acids, particularly EPA and DHA. The diversity in molecular species and structures results in different biological activities. Polar headgroups such as choline and amino groups, as well as n-3 polyunsaturated fatty acids in phospholipids, are crucial to our food system and health, especially regarding antioxidant activity, memory, improving immunity, and preventing cardiovascular disease.     

高效液相色谱法测定动物组织中喹乙醇标示残留物

建立动物组织中喹乙醇标示残留物3- 甲基喹噁啉-2- 羧酸(MQCA)的高效液相色谱测定方法。肌肉组织通过盐酸水解提取MQCA,阴离子固相萃取柱净化,高效液相色谱定量。方法在4.0～200μg/kg 添加范围内的平均回收率为82.1%～90.3%,相对标准偏差均小于7%,方法定量限为4.0μg/kg。