Effect of particle size of chia seeds on bioaccessibility of phenolic compounds during in vitro digestion

Figures & data

Table 1. Simulated salivary (SSF), gastric (SGF) and intestinal fluids (SIF)

	SSF	SGF	SIF
KCl (g)	0.563	0.514	0.507
KH2PO4 (g)	0.252	0.122	0.109
NaHCO3 (g)	0.571	2.1	7.14
NaCl (g)	-	2.761	2.246
MgCl2(H2O)6 (g)	0.015	0.020	0.067
CH5NO3 (g)	0.0095	0.075	-
CaCl2(H2O)2 (g)	0.110	0.022	0.088
1 M HCl (mL)	1.08	15.6	-
Final vol. (mL)	500	1000	1000
pH	6.5 ± 0.1	3 ± 0.1	Around 8.0^a

^aNo adjustment of pH in SIF.

Table 2. Particle size of each sample

Treatment	Time mill^a	Screen mesh (mm)
	seconds	1.60–1.25	1.25–0.73	0.73–0.50	< 0.50
F.C.W. Whole	-	0.5%	99.5%	0	0
F.C.B. Large	5	0	60%	20%	20%
F.C.M. Medium	30	0	0	60%	40%
F.C.S. Small	60	0	0	40%	60%
F. C.F. Flour	-	0	70%	20%	10%

^aChia seeds using a coffee mill (150 W, Model 4041, Braun, Mexico).

Figure 1. Photographs of whole bran treatments milled from the same chia seeds; scale bar represents 1.61 cm. The A treatment is described as Chia “stabilized flour”, with particle size varying (1.25-<0.5 mm). The B treatment was milled is described as Chia “Size Small”, with particle size varying (0.73-<0.5 mm). The C treatment was milled is described as Chia “Size Medium”, with particle size varying (0.73-<0.5 mm). The D treatment was milled is described as Chia “Size Big”, with particle size varying (1.25-<0.5 mm). The E treatment was milled is described as Chia “Whole”, with size varying (1.60-<0.73 mm).

Table 3. Mean values of fatty acid composition of chia seeds and flour after and before vitro digestion

	16:00	18:00	18:01	18:02	18:03	SAT (%)	PUFA (%)	Ω-6/Ω-3 (ratio)	PUFA:SAT
	(%)	(%)	(%)	(%)	(%)				(ratio)
Whole After	nd	nd	nd	nd	nd	_	_	_	_
Before	nd	nd	nd	nd	nd	_	_	_	_
Sizelarge After	6,33^b	3,10^b	5,98^a	16,35^b	45,47^b	9,4^a	90,6^a	0,36^b	9,7^a
Before	6,23^b	3,13^b	5,96^a	16,36^b	45,46^b	9,7^a	90,3^a	0,36^b	9,3^a
Medium After	7,10^a	3,40^b	8,20^b	20,69^c	53,28^c	10,4^a	89,6^a	0,39^a	8,6^a
Before	7,04^a	3,38^b	8,19^b	20,66^c	53,29^c	10,8^a	89,2^a	0,39^a	8,3^a
Small After	7,40^a	3,61^a	8,12^b	20,50^c	52,92^c	11,1^a	88,9^a	0,39^a	8,0^a
Before	7,38^a	3,71^a	8,02^b	20,55^c	52,91^c	11,5^a	88,5^a	0,39^a	7,7^a
F. Flour After	7,82^a	3,48^a	7,16^a	20,69^c	53,61^c	11,3^a	88,7^a	0,39^a	7,9^a
Before	7,83^a	3,44^a	7,17^a	20,65^c	53,63^c	11,7^a	88,3^a	0,39^a	7,5^a

Means (of three replicates) in a column within a group with different letters show significant difference in fatty acid composition (p < 0.05) according to Tukey test.

Table 4. Mean values of phenolic compounds, TBAR´s and PV of chia seeds and flour before and after vitro digestion

	mg GAE/g dry sample	TBARs mgMDA/kg	PV µmol/kg
CW-Whole After	0.76 ± 0.02^a	3.6 ± 0.8^a	0.7 ± 0.1^a
Before	0.42 ± 0.05^a
CL-Large After	3.66 ± 0.58^bc	7.6 ± 0.6^b	2.2 ± 0.2^b
Before	3.28 ± 0.32^c
CM-Medium After	4.68 ± 0.16^c	9.4 ± 0.6^b	2.6 ± 0.2^b
Before	3.82 ± 0. 31^c
CS-Small After	4.33 ± 0.40^bc	9.7 ± 0.6^b	2.5 ± 0.2^b
Before	0.76 ± 0.02^a
CF-F. Flour After	3.60 ± 0.04^b	8.9 ± 0.7^b	2.3 ± 0.2^a
Before	3.01 ± 0.33^c

Means (of three replicates) in a column within a group with different letters show significant difference in phenolic compounds (p < 0.05) according to Tukey test.

Table 5. Changes in the quality of milled chia seeds (CM) stored at three different temperatures

Storage time (day)	TBARS (mg MDA/kg)	PV (meq O2/kg)
23°C (T1)
0	9.4 ± 0.6^a	2.6 ± 0.2^a
7	10.6 ± 0.6^a	4.1 ± 0.3^b
14	10.3 ± 0.5^a	6.3 ± 0.2^c
21	10.3 ± 0.8^a	3.6 ± 0.2^b
28	10.1 ± 0.7^a	2.6 ± 0.2^a
5°C (T2)
0	9.4 ± 0.6^a	2.6 ± 0.2^a
7	9.6 ± 0.7^a	2.5 ± 0.3^a
14	9.3 ± 0.5^a	2.2 ± 0.3^a
21	9.3 ± 0.6^a	2.6 ± 0.3^a
28	11.1 ± 0.6^b	2.7 ± 0.2^a
−18°C (T3)
0	9.4 ± 0.6^a	2.6 ± 0.2^a
7	10.1 ± 0.7^a	2.7 ± 0.3^a
14	10.4 ± 0.4^a	2.2 ± 0.3^a
21	9.4 ± 0.4^a	2.1 ± 0.2^a
28	9.9 ± 0.6^a	2.9 ± 0.2^b

Means (of three replicates) in a column within a group with different letters show significant difference in phenolic compounds (p < 0.05) according to Tukey test.