Total phenolic content and antioxidant capacity of agri-food waste and by-products

Figures & data

Figure 1. Graphical representation of physiological extraction.

Table 1. Chemical composition of AFW and by-products (% w/w on DM basis).

	DM	CP	EE	NDF	ADF	ADL	Ash	GE, MJ/kg
FVW	12.3 ± 2.20	9.9 ± 1.11	0.8 ± 0.50	22.2 ± 0.41	16.6 ± 0.52	10.2 ± 0.28	6.1 ± 0.22	16.4
Orange peel	26.6 ± 1.24	3.5 ± 2.02	1.7 ± 0.52	10.0 ± 1.30	7.6 ± 1.71	1.8 ± 0.01	3.8 ± 0.24	15.92
Strawberries	7.0 ± 1.21	7.7 ± 1.40	1.5 ± 0.30	12.8 ± 0.54	9.7 ± 1.58	5.7 ± 0.81	4.9 ± 0.58	16.99
Citrus pulp	93.7 ± 1.22	5.0 ± 1.14	2.6 ± 0.32	23.0 ± 0.60	16.2 ± 0.76	3.8 ± 1.03	9.0 ± 0.88	16.04
Grape marc	26.4 ± 1.30	8.0 ± 0.30	8.5 ± 0.22	20.8 ± 0.70	18.9 ± 1.49	12.9 ± 0.42	1.3 ± 1.26	16.86
Camelina sativa cake	92.3 ± 1.40	32.2 ± 1.40	7.7 ± 0.82	46.1 ± 1.03	22.0 ± 0.91	5.1 ± 0.39	5.9 ± 1.60	19.3
Whey	92.1 ± 0.22	13.0 ± 1.22	n.d.	n.d.	n.d.	n.d.	8.7 ± 0.56	18.54

Data are presented as mean ± standard deviation, (n = 3).AFW: Agri-food waste; FVW: fruit and vegetable waste; DM: dry matter; CP: crude protein; EE: ether extract; NDF: neutral detergent fibre; ADF: acid detergent fibre; ADL: acid detergent lignin; GE: gross energy; n.d.: not detected.

Table 2. Total phenolic content, antioxidant capacity (AOC) and anthocyanin content of chemical extracts (n = 3) (methanol extraction) from AFW and by-products (mean ± standard deviation).

Chemical
	Total phenolic content, mg TAE/100g	AOC, mg TE/100g	Anthocyanin content, mg/100g
FVW	1307.0 ± 182.85^b	1112.8 ± 340.62^c	18.8 ± 1.92^b
Orange peel	1583.0 ± 154.35^b	1703.9 ± 391.07^b	5.2 ± 0.53^c
Strawberries	1253.6 ± 98.57^b	1163.7 ± 276.90^cb	14.7 ± 2.13^b
Citrus pulp	565.6 ± 106.80^c	427.2 ± 109.91^d	3.4 ± 0.41^c
Grape marc	4480.5 ± 886.58^a	15440.7 ± 2671.85^a	29.6 ± 4.21^a
Camelina sativa cake	238.0 ± 4.24^c	730.5 ± 16.90^cd	1.9 ± 0.48^c
Whey	89.5 ± 18.41^c	43.3 ± 3.17^d	0.4 ± 0.02^d

AFW: Agri-food waste; FVW: fruit and vegetable waste; TAE: tannic acid equivalents; TE: trolox equivalents.Different superscript letters in columns indicate significant different data (p < .05).

Table 3. Total phenolic content, antioxidant capacity (AOC) and anthocyanin content of physiological extracts (n = 3) (in vitro digestion) from AFW and by-products (mean ± standard deviation).

Physiological
	Total phenolic content, mg TAE/100g	AOC, mg TE/100g	In vitro digestibility (% of DM)
FVW	3230.7 ± 122.26^a	3783.4 ± 604.43^b	78.7 ± 2.84^b
Orange peel	3596.0 ± 420.37^a	5233.9 ± 1518.18^ac	88.7 ± 3.44^a
Strawberries	2335.5 ± 462.26^c	4346.5 ± 1065.86^bc	86.8 ± 2.61^a
Citrus pulp	836.5 ± 18.43^b	4059.8 ± 55.84^b	78.9 ± 1.01^b
Grape marc	3552.2 ± 446.17^a	5511.4 ± 938.07^a	44.2 ± 2.31^d
Camelina sativa cake	879.7 ± 74.87^b	5262.3 ± 449.76^a	66.8 ± 0.82^c
Whey	219.2 ± 8.05^d	3258.3 ± 215.44^b	97.2 ± 1.61^a

AFW: Agri-food waste; FVW: fruit and vegetable waste; TAE: tannic acid equivalents; TE: trolox equivalents.Different superscript letters in columns indicate significant different data (p < .05).