Microencapsulated olive leaf extract enhances physicochemical stability of biscuits

Free and microencapsulated olive leaves extracts (OLE) have been proposed as natural antioxidant to prolong the stability of biscuits, under two accelerated storage conditions, with and without UV light. The equivalent of 500 mu g gallic acid/ g of dough has been selected as the sensory acceptable OLE concentration. Higher total phenol content and antioxidant activity were observed in biscuits enriched with both free (B-OLE) and microencapsulated (B-MCR) OLE, in comparison to the controls (B-C), being B-MCR less affected than B-OLE during storage. Higher oxidative stability was detected for B-MCR than B-OLE and B-C, when measured by both peroxide value and Oxitest. A general hardness decrease was observed for all the formulations during storage, being however B-MCR always harder than B-OLE and B-C, probably because of the interactions of the microsphere polymers (alginate and pectin) with water. Darker colours were measured for the enriched biscuits in comparison to the control ones, being all slightly affected during storage by water migration and lipid oxidation phenomena.

Automated summary

It was found that biscuits enriched with free and microencapsulated olive leaf extracts (OLE) can prolong their stability and are not affected by UV light. The concentration of 500 μg gallic acid/g of dough was selected as the acceptable OLE concentration. Biscuits enriched with both free (B-OLE) and microencapsulated (B-MCR) OLE exhibited higher total phenol content and antioxidant activity compared to the control (B-C), with B-MCR being less affected during storage. B-MCR also showed higher oxidative stability than B-OLE and B-C, as measured by peroxide value and Oxitest. All formulations showed a decrease in hardness during storage, though B-MCR remained harder than B-OLE and B-C, possibly due to the interaction of microsphere polymers with water. Enriched biscuits had darker colors compared to the controls, with slight effects during storage from water migration and lipid oxidation phenomena.