Effect of bilayer coating composed of polyvinyl alcohol, chitosan, and sodium alginate on salted duck eggs

Figures & data

Table 1. Film property changes during storage.

		0 day	15 days	30 days	45 days	60 days
MC (%)	S	9.22 ± 0.32^Aa	14.72 ± 0.56^Ab	16.02 ± 0.15^Ac	22.90 ± 0.65^Be	18.50 ± 1.32^Ad
	P	12.45 ± 0.68^Ca	20.43 ± 0.74^Bb	23.22 ± 0.34^Bc	24.96 ± 0.82^Cd	21.22 ± 0.22^Bb
	B	11.75 ± 0.62^Ba	13.60 ± 0.73^Aa	15.51 ± 0.53^Ab	22.04 ± 0.43^Ac	25.15 ± 1.52^Cd
WS (%)	S	91.52 ± 0.45^Ce	81.25 ± 0.08^Cd	70.87 ± 0.16^Cc	59.89 ± 1.98^Cb	53.43 ± 2.63^Ba
	P	14.50 ± 0.36^Ad	11.53 ± 0.65^Ab	11.40 ± 0.72^Ab	9.02 ± 0.26^Aa	12.40 ± 0.48^Ac
	B	42.08 ± 0.96^Bb	50.43 ± 1.73^Bd	46.58 ± 0.38^Bc	43.58 ± 2.30^Bb	38.11 ± 0.65^Ca
TS (MPa)	S	22.94 ± 2.67^Ba	21.63 ± 6.54^Aa	21.75 ± 1.09^Ba	19.60 ± 2.29^Aa	18.59 ± 2.77^Ba
	P	23.73 ± 1.86^Ba	23.27 ± 1.91^Aa	21.62 ± 2.71^Ba	24.63 ± 2.39^Ba	22.39 ± 2.96^Ba
	B	15.70 ± 2.57^Aa	19.38 ± 2.29^Aa	17.28 ± 2.83^Aa	17.79 ± 1.53^Aa	15.45 ± 1.33^Aa
EB (%)	S	106.82 ± 6.04^Aa	102.14 ± 1.16^Aa	109.84 ± 3.32^Ab	106.73 ± 2.39^Aa	104.79 ± 2.06^Aa
	P	150.13 ± 9.99^Bb	152.01 ± 9.04^Bb	150.90 ± 5.73^Bb	145.18 ± 3.39^Cab	136.33 ± 3.84^Ca
	B	109.79 ± 3.09^Ab	106.24 ± 2.33^Aa	110.49 ± 1.84^Ab	114.26 ± 0.83^Bb	112.39 ± 0.82^Bb

Values were expressed as average ± standard deviation (SD) (n = 3).

Different uppercase letters in the same column or different lower case letters in the same row indicated differences at p ≤ 0.05 level were significant.

S: The film composed of SA; P: the film composed of PVA and CHI; B: the bilayer film composed of PVA, CHI, and SA.

WC: Water content; WS: water solubility; TS: tensile strength; EB: elongation at break.

Figure 1. WVP changes of films during storage.

S: The film composed of SA; P: the film composed of PVA and CHI; B: the bilayer film composed of PVA, CHI, and SA.WVP: Water vapor permeability.

Figure 2. The water content (a) and pH (b) of SDEs during storage.

C: Non-coated SDEs; B: bilayer-coated SDEs; P: PVA–chitosan-coated SDEs; S: sodium alginate-coated SDEs.

Figure 3. The egg yolk oil exudation (a) and egg yolk gritty (b) during storage.

C: Non-coated SDEs; B: bilayer-coated SDEs; P: PVA–chitosan-coated SDEs; S: sodium alginate-coated SDEs

Figure 4. The total number of colonies of SDEs during storage.

C: Non-coated SDEs; B: bilayer-coated SDEs; P: PVA–chitosan-coated SDEs; S: sodium alginate-coated SDEs.

Table 2. Sensory evaluation of SDEs yolk during storage.

	Time/Day	Texture (10)	Color (10)	Odor (10)	Oil (10)	Score (40)
C	15	7.17 ± 0.61^d	7.23 ± 1.29^d	5.98 ± 0.95^d	9.10 ± 1.27^ef	29.48 ± 3.06^e
	30	5.67 ± 0.57^c	4.54 ± 0.53^c	3.04 ± 0.27^b	7.41 ± 0.95^d	20.68 ± 3.63^c
	45	3.63 ± 0.27^b	1.98 ± 0.29^b	1.23 ± 0.17^a	4.32 ± 0.43^b	11.16 ± 1.73^b
	60	1.85 ± 0.38^a	1.45 ± 0.24^a	1.11 ± 0.15^a	1.45 ± 0.25^a	5.86 ± 1.56^a
B	15	9.34 ± 1.43^f	9.54 ± 1.52^f	9.13 ± 0.98^g	9.46 ± 1.17^f	37.47 ± 4.43^g
	30	9.23 ± 0.83^f	9.13 ± 0.78^ef	8.67 ± 0.92^fg	9.11 ± 0.88^ef	36.14 ± 3.62^g
	45	7.57 ± 0.94^e	8.93 ± 0.87^ef	8.04 ± 1.15^f	8.87 ± 1.32^e	33.41 ± 3.52^f
	60	7.23 ± 0.88^de	7.35 ± 0.82^d	7.28 ± 0.95^e	8.65 ± 0.79^e	30.51 ± 2.42^e
S	15	9.03 ± 1.20^f	8.17 ± 1.32^e	8.78 ± 1.10f^g	8.26 ± 1.45^e	34.24 ± 3.76^f
	30	7.87 ± 1.03^e	7.11 ± 1.25^d	8.32 ± 1.29^f	7.32 ± 1.27^d	30.62 ± 4.16^e
	45	6.03 ± 1.23^cd	5.06 ± 1.20^c	5.76 ± 0.73^d	6.76 ± 0.95^cd	23.61 ± 3.27^cd
	60	5.55 ± 0.94^c	4.42 ± 1.26^c	4.38 ± 0.52^c	6.12 ± 0.43^c	20.47 ± 2.83^c
P	15	9.21 ± 1.07^f	9.24 ± 1.15^f	9.18 ± 1.34^g	8.34 ± 1.27^e	35.97 ± 4.62^fg
	30	8.31 ± 1.31^ef	8.08 ± 1.21^e	8.44 ± 1.20^f	7.23 ± 0.88^d	32.06 ± 4.27^ef
	45	6.27 ± 0.97^d	7.16 ± 0.93^d	7.06 ± 1.16^e	6.34 ± 1.10^c	26.83 ± 2.28^d
	60	6.07 ± 0.92^cd	6.97 ± 1.01^d	6.37 ± 1.04^de	6.13 ± 0.93^c	25.54 ± 2.62^d

C: The control non-coated SDEs; B: the two solutions coated SDEs; P: the PVA–chitosan-coated SDEs; S: the sodium alginate-coated SDEs

Values were expressed as average ± standard deviation (SD) (n = 10) with different letters indicate significant differences (p < 0.05).