Migration of silver from nanosilver–polyethylene composite packaging into food simulants

An analytical method for the determination of silver in food simulants (3% (w/v) aqueous acetic acid or 95% (v/v) aqueous ethanol) was developed based on inductively coupled plasma mass spectrometry (ICP-MS). Recoveries ranged from 87% to 109% and RSDs ranged from 0.7% to 7.8%. The procedure was applied to determine the migration of silver from nanosilver–polyethylene food packaging film into food simulants at different temperatures and migration times. Results indicated that the maximum migration ratios were 1.70%, 3.00% and 5.60% for 3% (w/v) aqueous acetic acid at 20, 40 and 70°C, respectively, while for 95% (v/v) aqueous ethanol the maximum migration ratios were 0.24%, 0.23% and 0.22% at 20, 40 and 70°C.     

Recycled paper–paperboard for food contact materials: Contaminants suspected and migration into foods and food simulant

Contaminant residues in food packaging is a new challenge of our time, as it may pose a threat for consumers. Higher levels of contaminants were observed in food packaging made by recycled materials, even if little information is available for some groups of contaminants. The present study proposes a procedure for analyzing three different groups of organic contaminants in recycled paper and paperboard. Seventeen commercial samples were analyzed for the presence of bisphenol A (BPA), bis (2-ethylhexyl) phthalate (DEHP), nonylphenol monoethoxylate (NMP) and nonylphenol di-ethoxilate (NDP). Not all the samples contained all the contaminants; BPA was the only substance present in all the samples. The concentrations detected were quite high and, in most of the cases, in agreement with results reported in previous studies. Substance migration tests from spiked/non-spiked samples for two dry foods and Tenax® food simulant were undertaken. BPA migration quotients were always lower than 1%, whereas the migration quotients of DEHP were higher than 2.0%. The highest nonylphenols migration quotients were 6.5% for NMP and 8.2% for NDP. Tenax® simulates well the contaminants migration from paperboard to dry food, in some cases being even more severe than the food.     

Simulation of the migration of mineral oil from recycled paperboard into dry foods by Tenax®?

Conventional migration testing for long-term storage at ambient temperature with Tenax^® was applied to a recycled paperboard as well as to the same paperboard with a polyethylene or polypropylene film in between. Test conditions were from the European Union plastic Regulation 10/2011, that is, 10 days at 60°C, but previous standard conditions of 10 days at 40°C were also applied. The results were compared with the migration into real packs made of the same packaging material containing six test foods and stored over 9 months. For the direct contact, simulation at 60°C overestimated the maximum migration of the saturated hydrocarbons in the real packs by 73%. Simulation reflected hardly any effect by the plastic films and resulted in an overestimation of the maximum migration into the real packs by a factor of 5.1 and 27 for the polyethylene and the polypropylene film, respectively. Analogous simulation was performed with polenta (corn semolina) instead of Tenax^®. Three main causes for this deviation were identified: (i) at 60°C, migration reached beyond n-C₃₅, whereas it ends at about n-C₂₄ in reality. (ii) Tenax^® is a far stronger adsorbent than foods, resulting in almost complete extraction. (iii) The significant barrier effect of polypropylene films at ambient temperature is lost at increased temperature. The suitability of such simulation for the prediction of long-term migration is questioned.     

Effect of relative humidity on the migration of benzophenone from paperboard into the food simulant Tenax® and modelling hereof

The aim of this study was to investigate the effect of relative humidity on the migration of benzophenone from paperboard into the food simulant Tenax®. Kinetic migration investigations were carried out with three relative humidities in the interval between 39% and >73%. All investigations were carried out at a constant temperature of 34°C. It was found that the migration of benzophenone after more than 30 days was 4.8 times higher at a relative humidity of 64%–71%, and 7.3 times higher at a relative humidity of >73%, compared with that at a relative humidity of 39%–49%. Diffusion and partition coefficients were derived from the results by using a software for modelling migration in multilayer materials. Both the diffusion coefficient and the partition coefficient, between paperboard and Tenax®, decrease with increasing relative humidity. The experimental results were correctly modelled only when the paperboard was regarded as a one-layer system as compared with a two-layer system: where the main part of the paperboard (B1) has a high diffusion rate and a thin part of the paperboard (B2) in contact with the foodstuff has a lower diffusion rate.     

Copper release from nano‑copper/polypropylene composite films to food and the forms of copper in food simulants

The influences of temperature, exposure time, different types of polypropylene (PP), (3-Aminopropyl) triethoxysilane (KH550) used as coupling agent, sterilizing conditions on copper migration from nano‑copper/PP composite films into food/ food simulants were explored. Results showed that copper migrated more easily from polypropylene (PPH) films with a maximum rate of 34.51%, compared to those from copolymer polypropylene (PPR) and block copolymer polypropylene (PPB) to 3% acetic acid (w/v). Gamma (γ) irradiation could significantly increase the copper migration (P < 0.05). Different forms of copper were found in different simulants. Copper crystals were found in 10% ethyl alcohol and identified by scanning electron microscopy and energy dispersed analysis of X-rays (SEM-EDX). The hydroxylation (%) of nano‑copper/PP films was less than 100%. These films had certain antioxidant and antimicrobial properties which could extend the shelf life of packaged food. The migration amount of copper into rice vinegar was the largest, with a maximum of 0.65 mg/ kg.Industrial relevanceAlthough nanomaterials are potentially beneficial for food packaging, migration of nanoparticles to the packaged food can be harmful to the human body. Therefore, it is very important to determine the presence and characterize the morphology of nanoparticles in food. In this paper, we have developed a new and effective packaging material containing nanoparticles and have explored the migration form and morphology in food simulants. In conjunction with the results of current study, nano‑copper/PP packaging material can be suggested for maintaining the product quality and has commercial potential.     

Enrichment of chips with fibre from a tiger-nut (Cyperus esculentus) milk co-product at ‘source of fibre foods’ and ‘high fibre content foods’ levels: impact on processing,physico-chemical and sensory properties

The impact of integrating a tiger-nut milk co-product into the wheat chip production process for enriching fibre content to meet European recommendations for ‘source of fibre foods’ and ‘high fibre content foods’ was studied. Four different flours, based on their composition and particle size, were obtained from the co-product. Wheat flour was substituted at the 5%, 10% and 20% levels with the co-product, and the processing, physico-chemical and sensory properties of chip were studied. In the baking phase, mass loss was more marked for the substituted samples (42%) than the control (34%), but differences diminished after the tempering time (33%) by absorbing moisture from the environment. This effect was related to the increased chips surface (≈43%) in the forming phase because dough retraction decreased. The co-product as a fibre source produced alterations to chip processing and its physico-chemical properties should be taken into account. However, chips positively impacted consumer acceptability.     

Metal–organic framework for the extraction and detection of pesticides from food commodities

Pesticide residues in food matrices, threatening the survival and development of humanity, is one of the critical challenges worldwide. Metal–organic frameworks (MOFs) possess excellent properties, which include excellent adsorption capacity, tailorable shape and size, hierarchical structure, numerous surface-active sites, high specific surface areas, high chemical stabilities, and ease of modification and functionalization. These promising properties render MOFs as advantageous porous materials for the extraction and detection of pesticides in food samples. This review is based on a brief introduction of MOFs and highlights recent advances in pesticide extraction and detection through MOFs. Furthermore, the challenges and prospects in this field are also described.     

Use of ultrasounds in the food industry–Methods and effects on quality,safety, and organoleptic characteristics of foods: A review

The use of ultrasounds has recently gained significant interest in the food industry mainly due to the new trends of consumers toward functional foods. Offering several advantages, this form of energy can be applied for the improvement of qualitative characteristics of high-quality foods as well as for assuring safety of a vast variety of foodstuffs, and at the same time minimizing any negative effects of the sensory characteristics of foods. Furthermore, the non-destructive nature of this technology offers several opportunities for the compositional analysis of foods. However, further research is required for the improvement of related techniques and the reduction of application costs in order to render this technology efficient for industrial use. This review paper covers the main applications of ultrasounds as well as several advantages of the use of the technology in combination with conventional techniques. The effects of ultrasounds on the characteristics, microbial safety, and quality of several foods are also detailed     

Selection and molecular characterization of wine yeasts isolated from the ‘El Penedès’ area (Spain)

A study of the microbiota present during the wine fermentation of five grape varieties from the ‘El Penedès’ area (Spain) was carried out to select autochthonous yeast strains for industrial wine production. In this study we identified members of the genera Candida, Dekkera, Hanseniaspora, Kluyveromyces, Torulaspora, Zygosaccharomyces and Saccharomyces in wine fermentation microbiota. Strains of Saccharomyces cerevisiae, as responsible agents of the alcoholic fermentation, were considered for a selection protocol. In this work we applied different enological criteria for selection, but previously we have characterized and differentiated Saccharomyces isolates by molecular methods to reduce the number of strains to analyse. Three strains were selected to conduct fermentations according to their characteristics. Finally, using mitochondrial DNA restriction analysis we demonstrated that the autochthonous selected strains are important contributors to the wine fermentation.     

Improved method for the determination of 12 non-nutritive sweeteners and monitoring in various foods using liquid chromatography–tandem mass spectrometry

An improved and highly sensitive method was developed and validated for the determination of 12 (7 permitted and 5 non-permitted in Korea) non-nutritive sweeteners in various foods using liquid chromatography-electrospray ionisation-tandem mass spectrometry. The chromatographic separation was performed on an Xbridge BEH C18 column (3 mm × 100 mm, 2.5 μm) with gradient elution using 10 mM ammonium acetate in water and 10 mM ammonium acetate in methanol. Sample preparation consisted of simple dilution, homogenisation, centrifugation and purification with a C18 cartridge prior to analysis. The relative matrix effect (%ME) was within ±20% for all sweeteners. The method also showed good linearity (R² > 0.99). The limit of detection and limit of quantification values in sample were in the range of 0.02–2.66 and 0.06–8.05 mg kg^?1, respectively. The recoveries at three concentration levels ranged between 80% and 119%, with relative standard deviation values below 10%. In addition, the expanded uncertainties determined for 12 sweeteners in 5 different food matrices were confirmed to be <14%. Finally, the method was successfully applied to the analysis of sweeteners in 681 food samples purchased in Korea, Australia and Turkey. These results demonstrate that the method is suitable for the simultaneous determination of multiple-sweeteners in a variety of foods.     

Bisphenol A diglycidyl ether (BADGE) migrating from packaging material ‘disappears’ in food: reaction with food components

Bisphenol A diglycidyl ether (BADGE) is widely used as a monomer for coatings and adhesives for food-contact applications. Previous publications indicate that, after migration from packaging into foodstuffs, BADGE undergoes various reactions with unidentified food components. In order to elucidate the fate of BADGE, losses were determined after incubation with different foodstuffs and food components. Food proteins were identified as the main reaction partner with BADGE. Adduct formation was found with nucleophilic side-chains of amino acids. In vitro, cysteine exhibited significant activity. The previously reported occurrence of methylthio-derivatives of BADGE in foodstuffs was shown to originate from the reaction of BADGE with methionine. BADGE-methylthio derivatives can, therefore, be used as marker substances in foodstuffs for protein reactions with BADGE. The reported results offer a new viewpoint on the evaluation of BADGE migration. The hydrolysis and hydrochlorination derivatives subject to European legislation make up only a fraction of the totally migrated BADGE, and a further concern is that the toxic or allergenic potential of the protein adducts are unknown.     

Relevance of the air–water interfacial and foaming properties of (modified) wheat proteins for food systems

A shift from animal protein- to plant protein-based foods is crucial in transitioning toward a more sustainable global food system. Among food products typically stabilized by animal proteins, food foams represent a major category. Wheat proteins are ubiquitous and structurally diverse, which offers opportunities for exploiting them for food foam and air–water interface stabilization. Notably, they are often classified into those that are soluble in aqueous systems (albumins and globulins) and those that are not (gliadins and glutenins). However, gliadins are at least to an extent water extractable and thus surface active. We here provide a comprehensive overview of studies investigating the air–water interfacial and foaming properties of the different wheat protein fractions. Characteristics in model systems are related to the functional role that wheat proteins play in gas cell stabilization in existing wheat-based foods (bread dough, cake batter, and beer foam). Still, to further extend the applicability of wheat proteins, and particularly the poorly soluble glutenins, to other food foams, their modification is required. Different physical, (bio)chemical, and other modification strategies that have been utilized to alter the solubility and therefore the air–water interfacial and foaming properties of the gluten protein fraction are critically reviewed. Such approaches may open up new opportunities for the application of (modified) gluten proteins in other food products, such as plant-based meringues, whippable drinks, or ice cream. In each section, important knowledge gaps are highlighted and perspectives for research efforts that could lead to the rational design of wheat protein systems with enhanced functionality and overall an increased applicability in food industry are proposed.     

Effect of ionising radiation treatment on the specific migration characteristics of packaging–food simulant combinations: effect of type and dose of radiation

Migration levels of acetyl tributyl citrate (ATBC) plasticiser from polyvinyl chloride (PVC) film into the European Union specified aqueous food simulants (distilled water, 3% w/v acetic acid and 10% v/v ethanol) were monitored as a function of time. Migration testing was carried out at 40°C for 10 days. Determination of the analyte was performed by applying an analytical methodology based on surfactant (Triton X-114) mediated extraction prior to gas chromatographic-flame ionisation detection. PVC cling film used was subjected to ionising treatment with a [⁶⁰Co] source, as well as to electron-beam irradiation at doses equal to 5, 15 and 25 kGy, with the aim to compare the effect of type and dose of radiation on the specific migration behaviour of PVC. Equilibrium concentrations of acetyl tributyl citrate into the aqueous solvents covered the ranges 173–422?µg?l^?1 and 296–513?µg?l^?1 for gamma- and electron-irradiated PVC, respectively. Hence, e-beam irradiation resulted in significantly higher ATBC migration compared with gamma treatment. The highest extraction efficiency of the 10% ethanol solution was common in both gamma and e-beam treatments; distilled water demonstrated the lowest migration. Gamma-irradiation at intermediate doses up to 5 kGy produced no statistically significant (p?>?0.05) effect on ATBC migration into all three aqueous simulants; however, this does not apply for high-energy electrons. Both ionising treatments were similar in that they resulted in statistically significant (p?<?0.05) differences in plasticiser migrating amounts between non-irradiated and irradiated at doses of 15 and 25 kGy samples. Gamma-radiation did not affect the kinetics of plasticiser migration. On the contrary, electron-beam radiation produced shorter equilibration times for all food-simulating solvents tested at 40°C. The above values regarding ATBC migration into aqueous food simulants are far below the European Union restriction (1?mg?kg^?1 body weight) for both types of ionising radiation. Thus, PVC cling film may be used in food irradiation applications in contact with aqueous foodstuffs.     

Comparison of donor–acceptor and alumina columns for the clean-up of polycyclic aromatic hydrocarbons from edible oils

Two methods for clean-up and sample enrichment for the analysis of polycyclic aromatic hydrocarbons (PAHs) in edible oils are compared; a clean-up based on a donor–acceptor complex chromatography (DACC) column and a standardized method widely used in the food industry consisting in a low pressure column chromatography with alumina as stationary phase. Both methods are followed by a reversed-phase high-performance liquid chromatography with fluorescence detection for the separation and quantitation of each PAH. Certified materials were used in order to validate the methods. The limits of detection were lower than 1 ng/g and good selectivity was achieved in both cases. The DACC column clean-up is faster and better accuracies were obtained. The advantages and disadvantages of both methods are discussed.     

Distribution of serotypes and pulsotypes of Listeria monocytogenes from human,food and environmental isolates (Italy 2002–2005)

This work was undertaken to study the serotypes and pulsotypes of 674 Listeria monocytogenes isolates from human (57), food (558) and environmental (59) sources, collected from different Italian geographical areas during 2002–2005, to determine whether certain subtypes were associated with certain foods and more often involved in cases of listeriosis, and to determine possible geographical or temporal associations. Eleven different L. monocytogenes serotypes were found in the food, environmental and human isolates. Most isolates belonged to only four serotypes (1/2a, 1/2b, 1/2c, 4b). The isolates were divided into 133 distinct AscI pulsotypes grouped into 26 pulsogroups. Pulsogroups ranged from a minimum of 2 up to 212 isolates, and contained 1–19 different pulsotypes. When associations between subtypes and isolates from specific foods selected as being most frequently involved in cases of listeriosis were tested some of these associations were highly significant but not exclusive, indicating that there was no close correlation between specific subtypes and specific food products. Despite the limitations of this study (few human isolates versus many food isolates prevalently collected from one food category), we believe that a large-scale database of L. monocytogenes subtypes and a timely epidemiological investigation can facilitate risk assessment and outbreak detection and control.     

Effect of soy protein supplementation on the nutritive value of ‘gari’ (farina) from Manihot esculenta

The supplementary role of soy protein on cassava (Manihot esculenta) “gari” or farina was studied in 35 day-old albino rats of the Wistar strain (n=6 per group) for 10 days. Gari was supplemented with soy beans at 10 and 15% soy protein levels to produce “soy gari” and the performances of rats fed the test diets compared with those on a 10% casein diet. Protein efficiency ratio (PER), Net protein utilization (NPU), true digestibility (TD) and biological values (BV) were the parameters used to assess the nutritional performance of the diets based on weight gains and nitrogen balance. The PER for 10% casein, 10 and 15% soy protein-supplemented gari groups were 2.31, 1.85 and 1.94 respectively, while the corresponding values for NPU were 71.9, 65.8 and 64.1, respectively. The TD values for the 10% casein, 10 and 15% soy protein-fed rats were 97.2, 91.9 and 90.0, respectively, while the corresponding values for BV were 73.9, 70.9 and 71.5. The PER, NPU, TD and BV for 10% casein diet were significantly superior (P<0.05) to those of the soy gari diets which gave NPU, TD and BV values 89–97% of those of the casein diet. There were no significant differences (P>0.05) in these parameters between the 10 and 15% soy protein supplementation. Soy gari is safe to the consumer, because the procedures involved in processing soy beans and cassava ensure the elimination of toxic anti-nutritional factors known to impact negatively on nutrient availability, metabolic processes and growth. It is suggested that the consumption of soy gari at 10% soy protein supplementation be promoted in gari-eating areas, to ameliorate the endemic problems of protein deficiency disorders.     

Microbiological and biochemical changes in the traditional fermentation of soybean for ‘soy-daddawa’ — Nigerian food condiment

The traditional production of ‘daddawa’ from the fermentation of soybean involves predominantly Bacillus species notably B. subtilis, B. licheniformis and B. pumilus. AlthoughMicrococcus luteus and Staphylococcus epidermidis were present in relatively low numbers at the onset of fermentation, they do not appear to play any major role in the fermentation process. The bacterial population, pH and moisture content increased with fermentation. The titratable acidity increased in the first 24 h and then dropped as fermentation progressed. Amylase activity increased rapidly with fermentation attaining a peak at 48 h with a concomitant decrease in total soluble sugar level while the reducing sugar increased in the first 24 h and dropped. Protease activity also increased rapidly in the first 36 h and dropped giving higher amounts of free amino acids with fermentation. Lipase and Beta-fructofuranosidase activities were minimal in the fermenting seeds.