## 3 Results and Discussion
#### 3.1.2 Reducing Sugars and Antioxidant Characteristics
Perhaps during the process of processing cassava into tapioca, a certain amount of antioxidant compounds was retained in the raw material used; thus, adding this raw material to Luffa Powder may have resulted in increased antioxidant activity [50]. In aqueous extracts, the DPPH values ranged from 4.25 \(\pm\) 0.25 to 6.27 \(\pm\) 0.06 mg TE/g DM, with pure tapioca flour showing the highest activity at 6.27 \(\pm\) 0.06 mg TE/g DM and pure _L. cylindrica_ powder the lowest, at 4.25 \(\pm\) 0.25 mg TE/g DM. Previous studies have shown that potentially present antioxidants in tapioca, such as tannins (especially those with a low degree of polymerization) and saponins, are also highly soluble in ethanol and water-ethanol solutions [51; 52]. Hence, the values for antioxidant activity measured by the DPPH and ABTS methods in the ethanol extracts of luffa powder and tapioca flour mixtures are probably higher than in the aqueous extracts. Higher values of antioxidant activity measured by the DPPH and ABTS methods in the aqueous extract than in the ethanol extract for tapioca flour may be due to the several times higher solubility in water of L-ascorbic acid, which is also a potential antioxidant present in tapioca [53]. The ABTS radical scavenging capacity in ethanolic extracts demonstrated values from 4.56 \(\pm\) 0.04 to 6.11 \(\pm\) 0.18 mg TE/g DM. Pure tapioca flour exhibited the highest activity, at 6.11 \(\pm\) 0.18 mg TE/g DM, while pure _L. cylindrica_ powder showed the lowest, at 4.56 \(\pm\) 0.04 mg TE/g DM. In the aqueous extracts, ABTS values ranged from 3.67 \(\pm\) 0.70 to 6.33 \(\pm\) 0.06 mg TE/g DM, with pure tapioca flour again showing the highest activity, at 6.33 \(\pm\) 0.06 mg TE/g DM and pure _L. cylindrica_ powder the lowest, at 3.67 \(\pm\) 0.70 mg TE/g DM. The reducing activity values (measured by FRAP) in the ethanol extracts ranged from 0.046 to 0.101 mg FeSO\({}_{4}\)/g DM. Pure _L. cylindrica_ powder showed the highest reducing power, at 0.126 mg FeSO\({}_{4}\)/g DM, while the LP30/TF70 blend showed the lowest reducing activity, at 0.046 mg FeSO\({}_{4}\)/g DM. The remaining samples showed intermediate values: TF 100% at 0.072; LP70/TF30 at 0.070; and LP50/TF50 at 0.053 mg FeSO\({}_{4}\)/g DM. In aqueous extracts, FRAP values ranged from 0.041 to 0.126 mg FeSO\({}_{4}\)/g DM, with pure _L. cylindrica_ powder showing the highest value, at 0.126 mg FeSO\({}_{4}\)/g DM and pure tapioca flour showing the lowest reducing activity, at 0.041 mg FeSO\({}_{4}\)/g DM. The lower values of reducing substances in the mixtures of _L. cylindrica_ powder and tapioca flour were probably due to the overall low content of reducing substances in pure tapioca flour compared to pure _L. cylindrica_ powder. Studies confirm that the bioactive compounds contained in tapioca, which have the ability to donate electrons (such as carotenoids or polyphenols) and thus reduce iron (III) ions to iron (II) ions, occur in much smaller amounts than in _L. cylindrica_ powder [54; 55]. The statistical analysis revealed significant interaction effects between the sample type and extraction solvent for the DPPH (\(p\) < 0.01) and FRAP (\(p\) < 0.05) assays, while ABTS showed significant solvent effects (\(p\) < 0.01) but no significant sample-solvent interaction. The sample type alone showed no significant effect on antioxidant activities across all assays. These results indicate that _L. cylindrica_ seed press cake powder possesses notable antioxidant properties, particularly in terms of ferric reducing power, while the addition of tapioca flour generally enhanced radical scavenging activities in both the DPPH and ABTS assays. The extraction solvent significantly influenced the recovery of antioxidant compounds, with varying effects, depending on the specific assay method employed. It can be assumed that the tapioca flour used to enrich luffa powder largely retained its initial antioxidant content during the main cassava root processing processes such as cleaning, dehydration and drying.