Vol.:(0123456789) 1 3 Journal of Polymers and the Environment https://doi.org/10.1007/s10924-020-01706-x ORIGINAL PAPER Multi Response Optimization of Bioactive Starch Foam Composite Using Taguchi’s Method and Grey Relational Analysis Noppadon Janaum 1  · Thanawin Butsiri 1  · Pornnapa Kasemsiri 1  · Mutjarin Souvanh 2  · Uraiwan Pongsa 3  · Somnuk Theerakulpisut 4  · Salim Hiziroglu 5  · Manunya Okhawilai 6 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract In this study, bioactive foam composite samples made from cassava starch and bioactive agents were prepared. The mix proportions of raw materials in the samples were designed using Taguchi method coupled with Grey relational analysis. L16 orthogonal array with three factors including spent cofee ground (SCG), zinc oxide (ZnO) and oregano essential oil/ palm oil ratio (OEO/PO) at four-levels was chosen for determining an optimum mixture. Based on the signal-to-noise ratio and the analysis of variance of the results, additions of OEO/PO and SCG in the samples were the main factors in inhibition of Escherichia coli and Staphylococcus aureus. Furthermore, it was found that the increase of SCG, ZnO and PO in ratio of OEO/PO in the samples resulted in enhancement of fexural strength of bioactive foam composites. It appears that ZnO and OEO/PO were the major factors to improve water resistance of the samples. Also, the best ideal mixed proportion of the bioactive foam composite samples was obtained from Grey relational analysis. Keywords Biodegradability · Bioactive agents · Foam composite · Taguchi method · Grey relational analysis Introduction Use of biodegradable materials has attracted much attention due to its potential in ameliorating the adverse impact from using non-biodegradable products which were made from petroleum-based polymer. Over the years, starch-based bio- degradable packaging has been developed for various appli- cations, especially food packaging owing to its less toxicity, low cost and density, abundant resources and biodegradabil- ity [1–4]. Current trends in new food packaging technologies are not only focused on environmentally friendly products but also extend the shelf life and maintain the quality of food products [5–7]. Extracted natural active agents from herbs and spices have been successfully incorporated into biodegradable polymers [8–10]. The major compositions of bioactive agents are polyphenol compounds and antioxidants that can maintain food quality by inhibiting the growth of food borne bacteria and reducing oxidation in packed foods [1, 8, 11]. Ounkaew et al. [12] observed that starch/polyvinyl alcohol flms incorporated with the extracted spent cofee ground (ex-SCG) and 30 wt% citric acid showed the synergistic efect for antibacterial activities. The ex-SCG consisted of antibacterial agents such as chlorogenic acid, cafeic acid as well as other bioactive components that inhibited the growth of Escherichia coli and Staphylococcus aureus. Trongchuen et al. [8] also investigated the starch foam con- taining ex-SCG, spent cofee ground (SCG) and oregano oil (OEO). The synergistic efect of antibacterial activity was * Pornnapa Kasemsiri pornkas@kku.ac.th 1 Department of Chemical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen 40002, Thailand 2 Department of Microbiology Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand 3 Division of Industrial Engineering Technology, Faculty of Industry and Technology, Rajamangala University of Technology Rattanakosin, Wang Klai Kang Won Campus, Prachuap Khiri Khan 77110, Thailand 4 Energy Management and Conservation Ofce, Faculty of Engineering, Khon Kaen University, Khon Kaen 40002, Thailand 5 Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK 74078, USA 6 Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330, Thailand