Indian Meal Moth (Plodia Interpunctella)–Resistant Food Packaging Film Development Using Microencapsulated Cinnamon Oil

Insect‐resistant laminate films containing microencapsulated cinnamon oil (CO) were developed to protect food products from the Indian meal moth (Plodia interpunctella). CO microencapsulated with polyvinyl alcohol was incorporated with a printing ink and the ink mixture was applied to a low‐density polyethylene (LDPE) film as an ink coating. The coated LDPE surface was laminated with a polypropylene film. The laminate film impeded the invasion of moth larvae and repelled the larvae. The periods of time during which cinnamaldehyde level in the film remained above a minimum repelling concentration, predicted from the concentration profile, were 21, 21, and 10 d for cookies, chocolate, and caramel, respectively. Coating with microencapsulated ink did not alter the tensile or barrier properties of the laminate film. Microencapsulation effectively prevented volatilization of CO. The laminate film can be produced by modern film manufacturing lines and applied to protect food from Indian meal moth damage.     

Microencapsulation of Essential Oil for Insect Repellent in Food Packaging System

Microcapsules containing thyme oil were prepared by in situ polymerization, using melamine–formaldehyde prepolymer as a wall material and 3 different emulsifiers (pluronic F‐127, tween 80, and sodium lauryl sulfate [SLS]). The general characteristics and release behavior of microcapsules, and their repellent effect against insects were investigated. The morphology of microcapsules using SLS was spherical shape with smooth surface. Microcapsules began to degrade at 150 °C. The particle size ranged from 1 to 10 μm and the loading efficiency of thyme oil was clearly affected by the emulsifier type. The highest loading efficiency appeared in microcapsules using SLS, which have good thermal resistance and smooth surface. The release rate of thyme oil from microcapsules was not only dependent on the storage temperature but also emulsifier type and microcapsules showed the sustained release properties for a long time. Diets, which were mixed with encapsulated thyme oil, expressed high insect repellent efficacy over 90% for 4 wk. Practical Application : Essential oil has various pest‐control characteristics, including repellent, ovicidal, and antifeedant efficacy. This work showed the sustained release properties and long‐lasting repellency of encapsulated essential oil. The results suggest that the great potential of essential oil microcapsules can be applied in coating or printing of food packaging materials for the insects repelling effects.     

Development of an Anti‐Insect Sachet Using a Polyvinyl Alcohol−Cinnamon Oil Polymer Strip Against Plodia interpunctella

Plodia interpunctella is a major storage pest that penetrates into food packaging and causes serious economic losses, as well as posing health risks. The goal of this study was to develop effective anti‐insect polymer strips against P. interpunctella by using plant essential oil (EO) and polyvinyl alcohol (PVA). The EO of cinnamon (Cinnamomum zeylanicum, CO) bark was used as an insect repellent, and fumigant mortality and the repellent activity of CO were measured to evaluate subsistent anti‐insect properties through newly designed traps. Repellent activity was also examined with several foods to simulate the storage environment. The mortality rate with CO after fumigation for 120 h was 63%. In the repellent assay, CO‐treated strips, but not control strips, effectively repelled P. interpunctella in both “with foods” and “without foods” groups. A PVA–CO strip sachet (PCO sachet) was developed to control the volatility of CO, and the PCO sachet demonstrated robust repellent activity. The loading contents of CO at the center and edges of strips were 39.41% and 39.59%, respectively, and through the results of FT‐IR, it inferred that CO was physically diffused in the PVA polymer matrix, not forming chemical bonds. In a release test using a gas chromatography, the PCO sachet showed remarkable controlled release of CO. These results demonstrate that the anti‐insect effects of CO can be maintained throughout the distribution and storage periods of foods using PCO sachets.     

Development of Natural Insect‐Repellent Loaded Halloysite Nanotubes and their Application to Food Packaging to Prevent Plodia interpunctella Infestation

The aims of this study were to develop insect‐proof halloysite nanotubes (HNTs) and apply the HNTs to a low‐density polyethylene (LDPE) film that will prevent Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), commonly known as Indian mealmoth, from infesting the food. Clove bud oil (CO), an insect repellent, was encapsulated into HNTs with polyethylenimine (PEI) to bring about controlled release of CO. Chemical composition and insecticidal effect of CO were examined. The Fourier transform infrared ( FTIR) spectrum of encapsulated CO was confirmed. The surface charges of uncoated HNTs (HNTs/CO) and coated HNTs with PEI by the layer‐by‐layer (LBL) method (HNTs/CO/LBL) were determined to be –37.23 and 36.33 mV, respectively. HNTs/CO/LBL showed slow, controlled release of CO compared to HNTs/CO. After 30 d, the residual amounts of CO in HNTs/CO and HNTs/CO/LBL were estimated to be 13.43 and 28.66 mg/g, respectively. HNTs/CO/LBL showed the most sustainable repellent effect. HNTs applied to gravure printing ink solution did not affect mechanical, optical, or thermal properties of the developed film. Gravure‐printed LDPE film containing HNTs/CO/LBL displayed the greatest preventive effect on insect penetration, indicating its potential for use as insect‐resistant food packaging materials.     

植物精油抗菌包装膜研究进展

植物精油作为天然来源的抑菌物质,在食品保鲜领域的应用越来越广泛。该文介绍其作为抗菌剂添加至聚合物基质中制备包装抗菌膜的研究现状,总结精油在膜材料中的构建方式、对膜物理性能、机械性能、抗菌性能的影响以及在食品保藏中的应用。指出植物精油抗菌膜材料存在的问题以及未来的研究重点和发展趋势,为精油抗菌膜的进一步发展提供思路。     

肉桂油对蛋清蛋白/可得然胶凝胶理化特性及释放肉桂醛性能的影响

卤制工艺中风味组分的控制释放有望对卤制品品质的工业标准化程度进行调控。以蛋清蛋白和可得然胶为基质材料,以肉桂油为风味组分代表,水油两相均质后通过热诱导法制备乳液凝胶,探究肉桂油添加对乳液凝胶特性及释放肉桂醛性能的影响。结果表明,与大豆油乳液凝胶相比,肉桂油乳液凝胶颜色偏黄,微观结构更加致密,持水率、硬度、储能模量和损耗模量等参数显著增加,且当肉桂油质量分数为5%时凝胶性能最强。随着肉桂油添加量的增加,凝胶转变时间缩短,同时乳液凝胶的黏弹性减弱,亮度增加、黄度降低。红外光谱证实了肉桂油中的肉桂醛与蛋清蛋白发生了席夫碱反应,从而促进乳液凝胶的形成及凝胶性能的提升。在模拟卤制品加工环境下,肉桂油乳液凝胶对所含肉桂醛具有良好的控释效果:水相中肉桂醛的释放率随肉桂油添加量的增加而减小,当肉桂油质量分数从5%增加至11%时,乳液凝胶在水中煮制1h后,肉桂醛的累积释放率降低35.44%;与在水中煮制相比,调味料氯化钠、醋酸与乙醇可促进水相中肉桂醛的释放,且在醋酸中的累积释放率增幅最大(15.95%);但模拟卤制基质中的蛋白质和多糖会抑制肉桂醛的释放,累积释放率降低9.58%以上。乳液凝胶在模拟食品加工过程中能维持原有块状形貌,但在酸性条件下质地变硬、体积缩小、损失率最大,且凝胶结构破坏程度最严重,促进了肉桂醛的释放。因此,蛋清蛋白/可得然胶乳液凝胶的质地与释放性能可通过肉桂油的活性填充进行调控。研究结果旨在为食品工业中风味控释技术的开发提供理论参考。     

Microencapsulation of Fish Oil by Spray Granulation and Fluid Bed Film Coating

Abstract: The stability of microencapsulated fish oil prepared with 2 production processes, spray granulation (SG) and SG followed by film coating (SG-FC) using a fluid bed equipment, was investigated. In the 1st process, 3 types of fish oil used were based on the ratios of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (10/50, 33/22, and 18/12). Each type was emulsified with soluble soybean polysaccharide (SSPS) and maltodextrin to produce 25% oil powders. In the 2nd process, 15% film coating of hydroxypropyl betacyclodextrin (HPBCD) was applied to the granules from the 1st process. The powder stability against oxidation was examined by measurement of peroxide values (PV) and headspace propanal after storage at room temperature and at 3 to 4 °C for 6 wk. Uncoated powder containing the lowest concentration of PUFA (18/12) was found to be stable during storage at room temperature with maximum PV of 3.98 ± 0.001 meq/kg oil. The PV increased sharply for uncoated powder with higher concentration of omega-3 (in 33/22 and 10/50 fish oils) after 3 wk storage. The PVs were in agreement with the concentration of propanal, and these 2 parameters remained constant for most of the uncoated powders stored at low temperature. Unexpectedly, the outcomes showed that the coated powders had lower stability than uncoated powders as indicated by higher initial PVs; more hydroperoxides were detected as well as increasing propanal concentration. The investigation suggests that the film-coating by HPBCD ineffectively protected fish oil as the coating process might have induced further oxidation; however, SG is a good method for producing fish oil powder and to protect it from oxidation because of the “onion skin” structure of granules produced in this process.     

肉桂精油的成分分析、抑菌和抗氧化活性及在食品保鲜中的应用进展

肉桂精油具有优良的抑菌和抗氧化活性,因此其作为一类天然安全的植物抑菌剂和抗氧化剂,在日常的食品保鲜中具有非常广阔的应用前景。文章分析了不同生长环境、不同提取部位和不同提取方法得到的肉桂油的主要化学成分和含量,综述了肉桂油的抗菌、抗氧化性及其在食品保鲜中的应用,为肉桂精油进一步的开发和应用提供了参考。     

Inhibition of Fungal Growth on Wheat and Rye Bread by Modified Atmosphere Packaging and Active Packaging Using Volatile Mustard Essential Oil

ABSTRACT: Wheat and rye bread artificially inoculated with molds were packed in modified atmospheres of 0%, 50%, 75%, or 100% CO₂ balanced with N₂, and 3 levels of residual O₂, 1%, 0.03%, or <0.01%/O₂-absorber, and stored for 30 to 35 d. Modified atmosphere packaging (MAP) was quantitatively more effective for rye bread because fewer mold species grew at elevated CO₂. However, the major rye bread contaminant, Penicillium roqueforti , was the overall most CO₂-resistant mold and only the use of O₂-absorber could prevent growth of this species. On wheat bread, the most CO₂-tolerant mold was Penicillium commune , growing in 99% CO₂ (with high residual O₂), and Aspergillus flavus was the mold species that grew at lowest O₂ in 75% CO₂ treatment. The spoilage yeast/"chalk mold" Endomyces fibuliger was less affected by the different O₂ levels than the true filamentous molds, and none of the tested MAP treatments could prevent growth, but lag-phase was increased with O₂-absorber on wheat bread and decreased with 1% residual O₂ on rye bread. Experiments with volatile mustard oil showed that A. flavus and Eurotium repens were the most mustard oil-resistant species on wheat and rye bread, respectively. A combination strategy with MAP and mustard oil proved most optimal, and total inhibition was achieved with 2 μL mustard oil/rye bread slice and between 2 and 3 μL/wheat bread. Results indicated that the nature and surface area of the product influences effectiveness of active packaging with mustard oil.     

Optimization of Microencapsulation of Fish Oil with Gum Arabic/Casein/Beta‐Cyclodextrin Mixtures by Spray Drying

Fish oil was encapsulated with gum arabic/casein/beta‐cyclodextrin mixtures using spray drying. The processing parameters (solids concentration of the barrier solutions, ratio of oil to barrier materials, emulsifying temperature, and air inlet temperature) were optimized based on emulsion viscosity, emulsion stability, encapsulation efficiency, and yield. A suitable viscosity and high emulsion stability could increase encapsulation efficiency and yield. Encapsulation efficiency and yield were significantly affected by all the 4 parameters. Based on the results of orthogonal experiments, encapsulation efficiency and yield reached a maximum of 79.6% and 55.6%, respectively, at the optimal condition: solids concentration of 35%, ratios of oil to barrier materials of 3:7, emulsifying temperature of 55 °C, and air inlet temperature of 220 °C. Scanning electron microscopy analysis showed that fish oil microcapsules were nearly spherical with a smooth surface with droplet size ranging from 1 to 10 μm.     

New Trends in the Microencapsulation of Functional Fatty Acid‐Rich Oils Using Transglutaminase Catalyzed Crosslinking

Preparing stable protein‐based microcapsules containing functional fatty acids and oils for food applications has been a big challenge. However, recent advances with transglutaminase (TGase) enzyme as an effective protein cross‐linker could provide workable solutions for the encapsulation of omega‐3 and omega‐6 fatty acids without compromising their targeted release and their biological and physicochemical characteristics. The recent and available literature related to the microencapsulation techniques, physical and oxidative properties, and core retention and release mechanisms of TGase‐crosslinked microcapsules entrapping edible oils were reviewed. The effects of factors involved in microencapsulation processes, on the efficiency and quality of the produced innovative microcapsules were also discussed and highlighted. A brief focus has been finally addressed to new insights and additional knowledge on micro‐ and nanoencapsulation of lipophilic food‐grade ingredients by TGase‐induced gelation. Two dominant microencapsulation methods for fish, vegetable, and essential oils by TGase‐crosslinking are complex coacervation and emulsion‐based spray drying. The developed spherical particles (<100 μm) with some wrinkles and smooth surfaces showed an excellent encapsulation efficiency and yield. A negligible release rate and a substantial retention level can result for different lipid‐based cores covered by TGase‐crosslinked proteins during the oral digestion and storage. A significant structural, thermal and oxidative stability for edible oils‐loaded microcapsules in the presence of TGase can be also obtained.     

Microencapsulation of Nigella sativa seeds oil containing thymoquinone by spray‐drying for functional yogurt production

The present work reports on the microencapsulation of Nigella sativa seeds oil containing thymoquinone (TQ) by spray‐drying, using modified starch (MS) and maltodextrin (MD) mixture as wall materials aimed at producing functional yogurt. First, the impact of different ratios of MS/MD on microencapsulation efficiency (ME) and TQ retention was investigated. The highest ME (90.10%) was found in microcapsules prepared from emulsion with 80/20 ratio of MS/MD; however, the microcapsules prepared with 50/50 ratio was selected for considering TQ stability under storage conditions and functional yogurt production due to an acceptable ME (89.48%) and better TQ retention (61.12%). The results showed that the microcapsules stored at refrigerator temperature had the highest content of TQ after 4 weeks. Moreover, the results of chemical and sensory analysis suggest that N. sativa seeds oil microcapsules can be used for producing functional yogurt due to high stability of TQ and proper chemical and sensory properties.     

食品包装纸中的饱和烃矿物油向食品模拟物Tenax的迁移和安全评估

研究食品包装纸中饱和烃矿物油(MOSH)向食品模拟物Tenax的迁移,考虑了不同类型包装纸在不同温度下(25℃、40℃、100℃)的迁移行为,并采用毒理学关注阈值(TTC)的方法对MOSH进行安全评估。结果表明:温度一定时,厚度和克重是影响食品包装纸中MOSH迁移的重要因素,厚度和克重越小,MOSH的迁移率越大;在一定条件下,温度越高,MOSH达到迁移平衡的时间越短(100℃,100 min;25℃,8 d),迁移率越大(100℃,24.81%;25℃,7.82%)。所测定的包装纸中MOSH达到迁移平衡时的迁移量,都明显超过了JECFA规定的特定迁移量0.6 mg/kg,容易发生迁移的MOSH主要集中在C16~C18和C23~C26,均属于容易在人体内蓄积的中低粘度矿物油。TTC评估结果表明:主要发生迁移的MOSH烃类经Cramer分类均属于Class I,从四种食品包装纸中迁移到Tenax的MOSH,估计每日摄入量(EDI)均明显高于对应的TTC阈值(1.8 mg/person·day),需要引起关注。     

Characteristics of Integrons and Associated Gene Cassettes in Antibiotic‐Resistant Escherichia coli Isolated from Free‐Ranging Food Animals in China

We investigated the occurrence of integrons in antibiotic‐resistant Escherichia coli strains isolated from free‐ranging food animals, including yaks, piglets, and chickens, in China, and characterized the gene cassettes harbored within the integrons. We examined 432 E. coli strains that exhibited resistance to at least one class of antibiotics. Integrase genes and associated gene cassettes were characterized by polymerase chain reaction (PCR) analysis, restriction fragment‐length polymorphism, DNA sequencing, conjugation experiments, and plasmid analysis. Twenty‐nine (6.7%) integrons were amplified from the 432 antimicrobial‐resistant (AMR) isolates evaluated. Specifically, class 1 and 2 integrons were detected in 26 (6%) and 3 (0.7%) strains, respectively. Meanwhile, 6 different gene cassettes, dfrA1, dfr12, aadA1, aadA2, sat1, and orfF, were detected within 6 variable regions (VRs), of which the dfrA1 + aadA1 array was the most common, identified in 12 of 26 class 1 integrons (46.1%). Meanwhile, only one class 2 integron contained a cassette, and the remaining two contained undetermined VRs. Finally, a conjugation assay confirmed the transfer of 4 different types of class 1 integrons into recipient strains, with plasmid sizes ranging from 20 to 30 kb. This is the first report examining the baseline AMR characteristics of E. coli within an extensive farming system of livestock animals in China. Given that integrons were detected in >6% of resistant E. coli strains, precautionary measures are required to prevent the spread of mobile genetic resistance determinants in food animals and monitor their emergence.     

Preparation of Methylated Products of A‐type Procyanidin Trimers in Cinnamon Bark and Their Protective Effects on Pancreatic β‐Cell

Polyphenols are partial metabolized to methylated conjugations in vivo, and then could modify bioavailability and bioactivity related to the uptake of parent compounds. Our previous studies have found that the antidiabetic effects of cinnamon barks are mainly related to polyphenol components, particularly A‐type procyanidin trimer cinnamtannin‐1 (CT1). It is necessary to understand the antidiabetic activity of methylations of CT1, nevertheless, sufficient amounts of methylated CT1 are difficult to obtain from metabolites in vivo. In this study, O‐methyl derivatives of CT1 were prepared through one‐pot methyl iodide reaction and isolation via column chromatography and RP‐HPLC semipreparation. The structures of O‐methyl substituents were determined through NMR (Nuclear Magnetic Resonance) and HPLC‐ESI‐MS (High‐performance liquid chromatography‐electrospray ionization‐mass spectrometry). Five purified O‐methyl substituents and 2 isomers of CT1 were obtained. Their protective effects on a palmitic acid‐induced pancreatic β‐cell apoptosis model were then evaluated. Results showed that the protective effects on pancreatic β‐cell of O‐methyl substituents were weaker than those of CT1. The results suggested that the methylation of catechol groups could be a relevant factor contributing to the decline of protective effects on pancreatic β‐cell of CT1 via obstructing quinone intermediate formation and affecting antioxidant abilities. The antidiabetic effects of O‐methyl derivatives of CT1 should be further determined by other antidiabetic models.