Incorporation of ground mustard seeds in an active packaging film: structural properties and controlled release of allyl isothiocyanate

Summary Ground mustard seeds can be incorporated into a packaging film material to have a controlled release of allyl isothiocyanates (AITC). However, the properties of film material loaded with ground mustard seeds need to be evaluated, since they might influence the release of AITC from the film materials. This study aimed to assess properties, including surface morphology, spectral analysis, crystallinity, the moisture‐related, thermal and mechanical properties, of the film materials incorporated with the ground seeds and the release of antimicrobial compounds. Furthermore, the effects of relative humidity on AITC release in the headspace were investigated. The results showed that incorporating a larger quantity of ground mustard seeds resulted in the quicker release of AITC due to direct exposure to moisture, as indicated by higher concentrations observed in the headspace. Meanwhile, a smaller quantity of ground seeds added to the film maintained the thermal properties of the materials until 100 °C, resulting in significantly better moisture‐related properties and higher mechanical strength in terms of tensile strength, elastic modulus, and strain at break. However, the smallest ratio (1:5) showed no release of AITC into the packaging headspace at 75% and 100% RH. Furthermore, the relative humidity led to the release of more AITC in the headspace, which is potentially applied for high‐moisture food products. Based on the influence of relative humidity on AITC concentrations, the mechanism of AITC release from the film materials is proposed, describing the AITC diffusion from ground mustard seeds, film, and headspace. The study demonstrated a better controlled release of allyl isothiocyanates into packaging headspace from the film containing larger quantity of ground mustard seed at higher relative humidity. This study also proposed the mechanism of AITC release from the film materials, describing the diffusion from ground mustard seeds through film and headspace.