Microencapsulation and storage stability of polyphenols from Vitis vinifera grape wastes

Wine production wastes are an interesting source of natural polyphenols. In this work, wine wastes

extracts were encapsulated through vibration nozzle microencapsulation using sodium alginate as polymer

and calcium chloride as hardening reagent. An experimental design approach was used to obtain

calcium-alginate microbeads with high polyphenol content and good morphological features. In this

way, the effect of pressure, frequency, voltage and the distance to the gelling bath were optimized for

two nozzles of 150 and 300 lm. Long-term stability of the microbeads was studied for 6 months taking

into account different storage conditions: temperatures (4 C and room temperature), in darkness and in

presence of light, and the addition of chitosan to the gelling bath. Encapsulated polyphenols were found

to be much more stable compared to free polyphenols regardless the encapsulation procedure and storage

conditions. Moreover, slightly lower degradation rates were obtained when chitosan was added to

the gelling bath.