Swiss Federal Institute of Technology Zurich Application of an oxygen scavenger to extend the shelf life of packaged bakery products Svenja Nick Institute of Food Science and Nutrition, ETH Zürich / Institute of Food and Beverage Innovation, ZHAW 1 Introduction 3 Results and Discussion Nowadays the consumer claims for fresh, convenient, and food For example, the palladium based oxygen scavenger reduced the products free from preservatives. The reduced use of initial oxygen concentration form 2 vol.% to 0.01 vol.% oxygen preservatives in bakery products supports mould growth and within 25.05 to 34 minutes in samples containing a toast slice. leads to a reduction of the mould free shelf life [1,2]. To ensure a The shelf life extension of the sample is shown in figure 2. The tolerable mould free shelf life and to maintain the product’s quality condition packed under a MA without carbon dioxide extended and safety modified atmosphere packaging combined with an the shelf life by seven days, whereas the condition packed with a oxygen scavengers (active packaging technology) can be used MA including carbon dioxide stayed mould free during the storage [3,4,5]. period of 50 days. 2 Method and Materials 100 80 The potential to extend the mould free shelf life of bakery 60 products free from preservatives was evaluated by the application 40 of modified atmosphere packaging combined with oxygen scavengers. For this purpose, three bakery products (toast, par- 20 Mouldy Mouldy samples/ % baked bun, gluten-free bread) were packed under either a normal 0 atmosphere, a modified atmosphere without (2 vol.% O2, 98 0 5 10 15 20 25 30 35 40 45 50 vol.% N2) or with CO2 (2 vol.% O2, 30 vol.% CO2, 68 vol.% N2) Time / d combined with different scavenger conditions (none, one or both). For each condition, a control sample was produced with a defined Toast, Mouldy samples, Pd, MAP solution to adjust the package’s relative humidity. Additionally, Toast, Mouldy samples, Pd, MAP with CO2 glass beads were packed in the control samples to adjust the Figure 2: Mould growth during storage period. Samples containing a toast slice, palladium based oxygen scavenger, packed with MAP including or excluding CO2, headspace of 255.75 cm3, stored under ambient headspace volume. Figure one shows an example for a sample conditions for 50 days. Oxygen measurement: mean ± standard deviation (n= 3), 10 samples per mould growth containing a bakery product (left) and the corresponding empty measurement. control packaging (right). Based on literature, mould growth is dependent on the present atmospheric conditions, therefore mould growth can be influenced by the MA composition. Thus, it is assumed that a combined effect of the present oxygen scavenger and the antifungal CO2 suppressed mould growth during a storage period of 50 days, whereas samples without CO2 were mouldy after seven days [5, 6]. 4 Conclusion This study showed that by using an application of MAP combined with different oxygen scavengers an initial 2 vol.% oxygen concentration can be reduced to 0.01 vol.% O2 and therefore the mould growth can be successfully postponed in bakery products. Figure 1: Illustration of a sample containing a bakery product and a palladium based oxygen scavenger (left) and the corresponding control sample (right). References 1. Magan, N., Aldred, D., & Arroyo, M. (2012). Mould prevention in bread. Breadmaking: Improving quality, Second Edition (Second Edi). After packaging the initial oxygen reduction of the oxygen Woodhead Publishing Limited. https://doi.org/10.1533/9780857095695.3.597 2. Román, S., Sánchez-Siles, L. M., & Siegrist, M. (2017). The importance of food naturalness for consumers: Results of a systematic review. scavenger was measured. Subsequently, all samples were Trends in Food Science and Technology, 67, 44–57. https://doi.org/10.1016/j.tifs.2017.06.010 3. López-Rubio, A., Almenar, E., Hernandez-Muñoz, P., Lagarón, J. M., Catalá, R., & Gavara, R. (2004). Overview of active polymer-based inoculated with a spore suspension of Rhizopus stolonifer. During packaging technologies for food applications. Food Reviews International, 20(4), 357–387. https://doi.org/10.1081/FRI-200033462 a storage period of 50 days the change in the headspace’s 4. Pereira de Abreu, D. A., Cruz, J. M., & Paseiro Losada, P. (2012). Active and intelligent packaging for the food industry. Food Reviews International, 28(2), 146–187. https://doi.org/10.1080/87559129.2011.595022 oxygen concentration and mould growth was daily monitored 5. Siverksik, M., Rosnes, J. T., & Bergslien, H. (2002). Modified atmosphere packaging. In T. Ohlsson & N. Bengtsson (Eds.), Minimal processing technologies in the food industries (pp. 61–86). Woodhead Publishing. 6. Kotsianis, I. S., Giannou, V., & Tzia, C. (2002). Production and packaging of bakery products using MAP technology. Trends in Food Science and Technology, 13(9–10), 319–324. https://doi.org/10.1016/S0924-2244(02)00162-0 Partner/Sponsor:.