Study of the antioxidant and antidiabetic activity in vitro of free and encapsulated phenolic compounds of olive pomace

We studied the antioxidant and antidiabetic activity of the encapsulated and unencapsulated phenolic compounds of olive pomace. First, we determined the TPC and TFC of all the samples. We noted 49.40 ± 1.46 mg EGA/g of OP start GG, 29.91 ± 2.32 mg EGA/g of lyoph Tyr/Aconv, 26.73 ± 0.84 mg EGA/g of lyoph Tyr/Aμwave and 7.98 ± 2.49 mg EGA/g of lyoph PP/Aμwave, as for the content of TFC we noted very low content, 2.62 ± 0.85 mg EQ/g of OP start GG, 0.77 ± 0.06 mg EQ/g of lyoph Tyr/Aconv, 0.46 ± 0.31 mg EQ/g of lyoph Tyr/A μwave and 0.87 ± 0.19 mg EQ/g of lyoph PP/Aμwave. The TAC of all the samples was determined by DPPH and ABTS methods, trolox served as positive control. With the DPPH, IC50 value was noted in the case of the Tyr/Aconv and Tyr/Aμwave. On the other hand, for start GG and PP/A μwave, we note respectively 200 ± 0.15 μg/mL and 179.84 ± 0.29 μg/mL, the trolox 106.29 ± 2.46 μg/mL lower than that of the start GG and PP/A μwave. With the ABTS, we note respectively for Tyr/Aconv and Tyr/Aμwave, 180 ± 0.83 μg/mL and 176.56 ± 0.23 μg/mL, start GG and PP/Aμwave as well as the trolox the IC50 are respectively 37.37 ± 2.21 μg/mL, 61.81 ± 0.08 μg/mL and 56.09 ± 0.81 μg/mL. The antidiabetic activity was studied by inhibition of the enzyme α-amylase, acarbose was used as standard, the IC50 of the start GG, PP/Aμwave are respectively 100.19 ± 3.50 μg/mL and 72.28 ± 0.16 μg/mL, Tyr/Aconv 400 ± 0.40 μg/mL, Tyr/Aμwave 559.57 ± 1.82 μg/mL exert a less interesting inhibitory effect compared to the other samples. We note in the case of Ac 116.25 ± 2.04 μg/mL. This work highlights the advantages of the encapsulation process, and promotes olive pomace as a potential source of antidiabetic compounds. •Olive pomace contains a large number of phenolic compounds.•Phenolic compounds exert significant antioxidant and antidiabetic activity.•Encapsulation have greatly contributed to the increase of polyphenols antioxidant and antidiabetic activity.