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Ultrafine fibers of zein and anthocyanins as natural pH indicator

Prietto, Luciana, Pinto, Vania Zanella, El Halal, Shanise Lisie Mello, de Morais, Michele Greque, Costa, Jorge Alberto Vieira, Lim, Loong‐Tak, Dias, Alvaro Renato Guerra, Zavareze, Elessandra da Rosa
Journal of the science of food and agriculture 2018 v.98 no.7 pp. 2735-2741
active food packaging, anthocyanins, buffers, color, contact angle, dyes, encapsulation, pH, polymers, zein
BACKGROUND: pH‐sensitive indicator membranes, which are useful for pharmaceutical, food, and packaging applications, can be formed by encapsulating halochromic compounds within various solid supports. Accordingly, electrospinning is a versatile technique for the development of these indicators, by entrapping pH dyes within ultrafine polymer fibers. RESULTS: The ultrafine zein fibers, containing 5% (w/v) anthocyanins, had an average diameter of 510 nm. The pH‐sensitive membrane exhibited color changes from pink to green when exposed to acidic and alkaline buffers, respectively. The contact angle was negligible after 10 and 2 s for neat and 5% anthocyanin‐loaded zein membranes, respectively. CONCLUSION: The pH membranes exhibited color changes in a board pH range, which can potentially be used in various active packaging applications. © 2017 Society of Chemical Industry