Phenolic Acid Content and Antioxidant Properties of Extruded Corn Snacks Enriched with Kale

Table 1

Content of phenolic acids in corn snacks with addition of kale (2, 4, 6, and 8%) (n = 3).

Phenolic acid	Yield of phenolic acids from snack samples (µg·g^−1 of dry weight)
	Corn snacks	Snacks + 2% kale	Snacks + 4% kale	Snacks + 6% kale	Snacks + 8% kale
Protocatechuic	—	0.054	0.061	0.135	0.193
RSD%	—	2.34	3.66	1.21	0.33
4-OH-Benzoic	BQL	0.114	0.120	0.213	0.248
RSD%	—	0.24	1.78	2.55	3.21
Vanillic	—	0.757	0.810	1.028	1.173
RSD%	—	0.41	1.67	3.46	4.22
trans-Caffeic	—	0.218	0.223	0.293	0.374
RSD%	—	4.12	3.45	0.06	0.32
cis-Caffeic	—	0.075	0.068	0.103	0.105
RSD%	—	3.67	2.11	0.98	1.34
trans-p-Coumaric	0.636	1.062	1.004	1.255	1.246
RSD%	3.34	2.11	2.78	1.82	1.45
cis-p-Coumaric	0.013	0.210	0.351	0.439	0.448
RSD%	3.21	4.15	4.21	0.43	2.54
trans-Ferulic	0.126	0.599	0.617	1.309	1.690
RSD%	0.12	1.34	1.87	3.24	1.76
cis-Ferulic	0.421	1.017	1.928	2.533	2.920
RSD%	3.56	2.24	0.34	0.76	2.45
Salicylic	0.197	0.221	0.267	0.315	0.370
RSD%	4.87	3.25	1.67	4.79	0.34
3-OH-Cinnamic	—	—	—	BQL	0.155
RSD%	—	—	—	—	2.98
trans-Sinapic	BQL	2.944	3.335	4.177	5.787
RSD%	—	4.21	3.45	1.31	2.15
cis-Sinapic	BQL	2.043	3.070	5.867	7.414
RSD%	—	2.34	4.12	1.21	2.31

RSD% = relative standard deviation (n = 3); BQL = peak detected, concentration lower than the LOQ but higher than the LOD.