engleski

Fourier transform infrared spectroscopy for characterization of pectin biofilms enriched with mandarin peel extracts

Mandarins are an important crop used mainly in the food industry for the production of fresh juice, with the peel being the main by-product during processing. Mandarin peels, which accounts for about half of the fruit mass, is a rich source of value-added compounds. Therefore, reliable and practical methods for releasing natural compounds from them are of great interest. In this context, the present study describes the concept of practical reuse of mandarin peels for the production of edible pectin-based biofilms. First, the mandarin peel extracts were obtained by refluxing (3 h) using water containing different mass fractions of mandarin peels (7.5, 15, and 30 g). Subsequently, the obtained mandarin peel extracts were used on a water basis to dissolve 1% pectin powder. After addition of glycerol (50 and 70%) and calcium chloride (1%), the biofilms were prepared by casting method and analysed by Fourier transform infrared spectroscopy (FTIR). The FTIR results confirmed that there were no differences between the pectin biofilms with the addition of mandarin peel extracts, i.e., the structural characterization of the edible coatings revealed that the different mass fractions of mandarin peel used in the preparation of the biofilms did not affect their structure. The FTIR analyses also confirmed that all biofilms with mandarin peel extracts contained carbohydrates and phenols and were therefore richer than biofilms with water (control film). Overall, the mandarin peel waste could be successfully reused as a cheap bio-substrate for the isolation and conversion of extracts to produce new enriched edible materials, which is in line with the sustainability trend of bioorganic waste recycling.

mandarin peels ; biofilms ; structural characterization ; Fourier transform infrared spectroscopy

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