Application of palladium-based oxygen scavenger to extend the mould free shelf life of bakery products

An oxygen scavenging film based on a catalytic system with palladium (CSP) was combined with modified atmosphere (MA) packaging to extend the mould free shelf life (MFSL) of bakery products. Par-baked buns, toast bread and gluten-free bread inoculated with Aspergillus niger spores were packed in normal atmosphere (NA) and under MA (with 2 vol.-% of O2) with or without CSP. Mould growth was detected after 2–3 days on all products packed under NA as well as under MA without CO2 and CSP. Use of CO2 in MA extended the MFSL by 8–10 days, 16–18 days and 3–4 days for par-baked buns, toast and gluten-free bread, respectively. Use of CSP with MA reduced the oxygen concentration in headspace from 2 vol.-% to < 0.01 vol.-% within 105–190 min with all bakery products. This led to a further increase in MFSL of bakery products by 3–9 days

Evaluation of the potential of modified calcium carbonate as a carrier for unsaturated fatty acids in oxygen scavenging applications

Modified calcium carbonates (MCC) are inorganic mineral-based particles with a large surface area, which is enlarged by their porous internal structure consisting of hydroxyapatite and calcium carbonate crystal structures. Such materials have high potential for use as carriers for active substances such as oxygen scavenging agents. Oxygen scavengers are applied to packaging to preserve the quality of oxygen-sensitive products. This study investigated the potential of MCC as a novel carrier system for unsaturated fatty acids (UFAs), with the intention of developing an oxygen scavenger. Linoleic acid (LA) and oleic acid (OA) were loaded on MCC powder, and the loaded MCC particles were characterized and studied for their oxygen scavenging activity. For both LA and OA, amounts of 20 wt% loading on MCC were found to provide optimal surface area/volume ratios. Spreading UFAs over large surface areas of 31.6 and 49 m2 g-1 MCC enabled oxygen exposure and action on a multitude of molecular sites, resulting in oxygen scavenging rates of 12.2 ± 0.6 and 1.7 ± 0.2 mL O2 d-1 g-1, and maximum oxygen absorption capacities of >195.6 ± 13.5 and >165.0 ± 2.0 mL g-1, respectively. Oxygen scavenging activity decreased with increasing humidity (37-100% RH) and increased with rising temperatures (5-30 °C). Overall, highly porous MCC was concluded to be a suitable UFA carrier for oxygen scavenging applications in food packaging

Precision and accuracy of single-molecule FRET measurements - a multi-laboratory benchmark study

Single-molecule Förster resonance energy transfer (smFRET) is increasingly being used to determine distances, structures, and dynamics of biomolecules in vitro and in vivo. However, generalized protocols and FRET standards to ensure the reproducibility and accuracy of measurements of FRET efficiencies are currently lacking. Here we report the results of a comparative blind study in which 20 labs determined the FRET efficiencies (E) of several dye-labeled DNA duplexes. Using a unified, straightforward method, we obtained FRET efficiencies with s.d. between ±0.02 and ±0.05. We suggest experimental and computational procedures for converting FRET efficiencies into accurate distances, and discuss potential uncertainties in the experiment and the modeling. Our quantitative assessment of the reproducibility of intensity-based smFRET measurements and a unified correction procedure represents an important step toward the validation of distance networks, with the ultimate aim of achieving reliable structural models of biomolecular systems by smFRET-based hybrid methods

Evaluation of the Potential of Modified Calcium Carbonate as a Carrier for Unsaturated Fatty Acids in Oxygen Scavenging Applications

Modified calcium carbonates (MCC) are inorganic mineral-based particles with a large surface area, which is enlarged by their porous internal structure consisting of hydroxyapatite and calcium carbonate crystal structures. Such materials have high potential for use as carriers for active substances such as oxygen scavenging agents. Oxygen scavengers are applied to packaging to preserve the quality of oxygen-sensitive products. This study investigated the potential of MCC as a novel carrier system for unsaturated fatty acids (UFAs), with the intention of developing an oxygen scavenger. Linoleic acid (LA) and oleic acid (OA) were loaded on MCC powder, and the loaded MCC particles were characterized and studied for their oxygen scavenging activity. For both LA and OA, amounts of 20 wt% loading on MCC were found to provide optimal surface area/volume ratios. Spreading UFAs over large surface areas of 31.6 and 49 m2 g−1 MCC enabled oxygen exposure and action on a multitude of molecular sites, resulting in oxygen scavenging rates of 12.2 ± 0.6 and 1.7 ± 0.2 mL O2 d−1 g−1, and maximum oxygen absorption capacities of &gt;195.6 ± 13.5 and &gt;165.0 ± 2.0 mL g−1, respectively. Oxygen scavenging activity decreased with increasing humidity (37–100% RH) and increased with rising temperatures (5–30 °C). Overall, highly porous MCC was concluded to be a suitable UFA carrier for oxygen scavenging applications in food packaging

Major technical challenges to overcome for successful exploitation of active and intelligent packaging technologies

Active and Intelligent packaging (AIP) technologies have huge potentials to optimise the food supply chain, to better preserve the quality of the food and enhance the consciousness of the utilisation of food. During the last decades, an extensive research on AIP technologies is being undertaken. However, only very few of these technologies have been implemented successfully in commercial food packaging systems. To identify the key technical, social, economic and legislative factors relevant for a successful development of AIP solutions, a knowledge-based network, European COST Action “Active and intelligent fibre-based packaging-innovation and market introduction (ActInPak)” has been initiated. Currently, 43 countries are involved in the network, with participants representing 209 academic institutions, 35 technical centres, and 83 industrial partners. Among the hurdles for commercial exploitation of AIP technologies, technological challenges are very crucial for successful development of such solutions. Within the COST Action, AIP technologies have been reviewed to identify the most promising technologies. Afterwards, through expert panel discussions and workshops with participants from academic institutions and industrial partners, major technological challenges for successful implementation of such AIP technologies have been identified and discussed in depth. The major technological challenges have been classified as: - Active component: Availability, storage, release, consistence, quality - Intelligent component: Resources, reliability, quality, stability - Integration in packaging: Integration methods, stability of active or intelligent component, activation - Packaging of food: Interaction with food, organoleptic, food safety - Logistic: Information flow, storage conditions, shelf life, sensitivity, deactivation - Quality control: Stability of AIP, quality control at suppliers, producers, food packers, and consumers - End of life: Recyclability, environmental impact, food wast

Sustainable antimicrobial packaging technologies

In the food packaging sector, innovative packaging technologies have been developed including active packaging. Thereby, antimicrobial packaging systems have been designed to inhibit the growth of spoilage and pathogenic microorganisms in packaged food. In this manner, the shelf life of food products can be extended while ensuring their quality, safety, and integrity. This in turn can lead to a reduction of food waste and thereby contribute to a more sustainable handling of food. Taken into account the replacement of the petroleum‐based commodity plastics by materials arising from biological and renewable resources, this chapter presents the latest developments of sustainable antimicrobial packaging systems for potential food application. The focus is on bioactive substances that have been incorporated into biopolymer matrices derived from renewable resources and that have been shown to provide antimicrobial activity against foodborne pathogens and spoilage microorganisms. Special emphasis is placed on publications where the antimicrobial packaging has been successfully tested on food systems. In addition, the role of active packaging, the functions of antimicrobial food packaging systems, and the most studied bioactive compounds such as essential oils, phenolic compounds, organic acids, bacteriocins, enzymes, and chitosan are elucidated

Active packaging

In the food packaging sector, the potential of nanotechnology is actively explored including active packaging. The transformation of active compounds from micro to nanoscale offers thereby a new opportunity. In this chapter, the role of nanotechnology in active packaging is described and a wide range of nanomaterials providing active functions to food packaging are presented. Thereby, the focus is set on nanomaterials which are not “nano” by nature, such as metals and metal oxides, but are applied at nanoscale to provide/enhance active functions. Special emphasis is given to inorganic nanoparticles expressing antimicrobial activities. The potential application of nano-carriers containing bioactive substances for antimicrobial packaging is also addressed. Furthermore, oxygen- and ethylene-scavenging systems based on active nanomaterials are presented

Intelligente und smarte Verpackungen

Sichere und qualitativ hochwertige Lebensmittel werden vom Konsumenten vorausgesetzt. Dabei spielt die Verpackung eine grosse Rolle. Innovative Technologien wie intelligente und smarte Verpackungen ermöglichen eine Überwachung des aktuellen Qualitätszustands eines Lebensmittels und können diesen nach aussen kommunizieren

Development of palladium-based oxygen scavenger : optimization of substrate and palladium layer thickness

Oxygen scavenging films based on vacuum deposited palladium layers were developed to remove residual oxygen remaining in food packages after modified atmosphere packaging. Palladium (Pd) was coated on to a range of packaging films and in different thicknesses using magnetron sputtering technology. To improve the substrate surface, an additional silicon oxide (SiOx) layer was also applied to the films before Pd deposition. To determine the oxygen scavenging activity, the scavenger films were placed into an airtight cell, which was flushed with a gas mixture containing 2 vol.% oxygen and 5 vol.% hydrogen. The results showed that the oxygen scavenging rate was strongly dependent on the coating substrate as well as on the Pd deposition thickness. Packaging films such as polyethylene terephthalate, aluminium oxide-coated polyethylene terephthalate, oriented polypropylene and polylactic acid were found to be the most suitable substrates for Pd-based oxygen scavengers. Moreover, it was demonstrated that the intermediate SiOx layer between the substrate and the Pd layer led to a substantial increase in the oxygen scavenging activity rate (up to 33-fold) for all applied packaging films. Additionally, it was shown that the optimal Pd layer thickness for the investigated oxygen scavenging films lies between 0.7 and 3.4 nm. The resulting scavenger films have the potential to scavenge residual headspace oxygen of sensitive foods within a matter of minutes leading to shelf life extension and overall quality improvements