Effect of Modified Atmosphere, Vacuum and Polyethylene Packaging on Physicochemical and Microbial Quality of Chestnuts (Castanea sativa) during Storage

Figures & data

Table 1. Oxygen (O₂), carbon dioxide (CO₂) values, and observations of chestnuts packaged and the control during storage

		Storage Time (months)
Atmospheres	Treatment	0	1	2	3	6
O2	PE	21.0 ± 0.1	14.8 ± 2.6	12.0 ± 1.1	17.6 ± 1.2	14.9 ± 1.9
	VAC	n.m.	0.2 ± 0.1	0.1 ± 0.1	0.1 ± 0.1	0.1 ± 0.1
	MAP	0.3 ± 0.1	0.0 ± 0.1	0.1 ± 0.1	0.2 ± 0.1	3.0 ± 1.6
	Control	21.0 ± 0.1	20.7 ± 0.1	20.7 ± 0.1	20.8 ± 0.1	21.0 ± 0.1
CO2	PE	0.0 ± 0.0	4.8 ± 0.6	4.7 ± 0.4	2.5 ± 1.0	3.4 ± 1.0
	VAC	n.m.	95.3 ± 2.4	97.2 ± 0.6	97.0 ± 1.0	94.0 ± 4.5
	MAP	31.7 ± 0.4	71.3 ± 1.5	80.5 ± 6.2	89.1 ± 2.5	63.3 ± 32.7
	Control	0.0 ± 0.0	0.2 ± 0.1	0.2 ± 0.1	0.1 ± 0.1	0.0 ± 0.0

n.m. – not measured

Figure 1. Visual appearance of packaged (PE – polyethylene; VAC – vacuum; MAP – modified atmosphere packaging) and control chestnuts throughout storage

Table 2. Changes in the color of shell and inside chestnuts packaged and the control throughout storage

		Storage Time (months)
		0	1	2	3	6	0	1	2	3	6
Parameters	Treatment	Shell					Inside the fruit
L*	PE	32.5 ± 2.96^b	28.5 ± 1.36^a,A	29.9 ± 3.12^a,A	37.5 ± 1.37^c,A	39.5 ± 1.51^d,D	85.9 ± 4.44^d	84.5 ± 2.85^c,d,A	83.7 ± 4.30^b,c,A	82.3 ± 3.28ª^,b,A	80.2 ± 2.64^a,A
	VAC	32.5 ± 2.96^b	29.8 ± 2.37^a,A,B	36.9 ± 2.17^c,C	38.6 ± 2.20^d,A,B	35.6 ± 1.95^c,B	85.9 ± 4.44^c	84.7 ± 3.03^b,c,A	83.6 ± 2.92ª^,b,A	82.3 ± 2.92^a,A	82.3 ± 3.30^a,B
	MAP	32.5 ± 2.96^a,b	30.7 ± 2.72^a,B	34.4 ± 2.59^b,B	41.3 ± 8.40^c,B	31.0 ± 2.75^a,A	85.9 ± 4.44^b	84.2 ± 2.82ª^,b,A	83.6 ± 2.97^a,A	83.1 ± 2.02^a,A	82.6 ± 3.32^a,B
	Control	32.5 ± 2.96^b	30.5 ± 2.41^a,B	30.1 ± 2.09^a,A	36.9 ± 2.00^b,A	37.3 ± 3.71^b,C	85.9 ± 4.44^b	84.4 ± 3.17^b,A	82.5 ± 4.34^a,A	82.6 ± 2.53^a,A	81.8 ± 2.78^a,B
a*	PE	12.2 ± 1.93^d	9.68 ± 1.54^c,A	9.25 ± 2.18^c,A,B	6.96 ± 1.48^b,A	5.82 ± 1.28^a,A	−3.03 ± 0.67^a	−2.58 ± 0.60^b,A	−2.56 ± 0.72^b,A	−1.95 ± 0.97^c,A	−1.90 ± 0.58^c,A
	VAC	12.2 ± 1.93^c	10.7 ± 2.00^b,A	9.71 ± 2.38^b,B	7.67 ± 1.95^a,A	8.31 ± 1.77^a,C	−3.03 ± 0.67^a	−2.67 ± 0.75^a,A	−2.21 ± 0.61^b,A	−2.09 ± 0.60^b,A	−1.99 ± 0.77^b,A
	MAP	12.2 ± 1.93^d	10.9 ± 2.14^c,d,A	9.32 ± 1.83^b,A,B	6.47 ± 2.15^a,A	10.3 ± 2.30^b,c,D	−3.03 ± 0.67^a	−2.25 ± 0.75^b,B	−2.18 ± 0.66^b,A	−2.13 ± 0.54^b,A	−2.11 ± 0.78^b,A
	Control	12.2 ± 1.93^c	10.1 ± 2.04^b,A	8.28 ± 1.98^a,A	7.53 ± 1.93^a,A	7.41 ± 1.60^a,B	−3.03 ± 0.67^a	−2.66 ± 0.59^a,A	−2.54 ± 1.12ª^,b,A	−2.11 ± 0.65^b,c,A	−1.80 ± 0.98^c,A
b*	PE	12.6 ± 4.40^c	4.25 ± 1.98^b,A	4.98 ± 3.64^b,A	1.13 ± 1.84^a,A	1.17 ± 1.65^a,A	22.9 ± 2.63^c	20.1 ± 2.07^a,A,B	22.2 ± 2.79^b,c,B	20.6 ± 2.26^a,A	20.8 ± 2.16^a,b,B
	VAC	12.6 ± 4.40^c	5.57 ± 3.15^b,A,B	3.79 ± 3.91^b,A	2.33 ± 3.18^a,A	1.85 ± 2.55^a,A	22.9 ± 2.63^b	20.4 ± 2.69^a,B	20.0 ± 2.64^a,A	19.5 ± 2.84^a,A	18.9 ± 2.60^a,A
	MAP	12.6 ± 4.40^c	7.05 ± 4.32^b,B	3.76 ± 3.35^a,A	1.65 ± 3.34^a,A	3.98 ± 3.94^a,B	22.9 ± 2.63^b	18.9 ± 2.62^a,A	20.1 ± 2.91^a,A	19.5 ± 2.56^a,A	19.5 ± 2.34^a,A
	Control	12.6 ± 4.40^c	6.60 ± 3.45^b,B	2.98 ± 2.44^a,A	1.84 ± 2.98^a,A	2.42 ± 2.33^a,A	22.9 ± 2.63^b	20.4 ± 2.62^a,B	22.9 ± 2.72^b,B	20.8 ± 2.29^a,A	21.2 ± 1.61^a,B
C	PE	17.6 ± 4.43^c	10.6 ± 2.17^b,A	10.7 ± 3.59^b,A	7.21 ± 1.80^a,A	6.07 ± 1.65^a,A	23.1 ± 2.70^c	20.3 ± 2.10^a,A,B	22.4 ± 2.82^b,c,B	20.7 ± 2.27^a,A	20.9 ± 2.18^a,b,B
	VAC	17.6 ± 4.43^d	12.2 ± 3.18^c,A,B	10.8 ± 3.62^b,A	8.31 ± 2.99^a,A	8.74 ± 2.35ª^,b,B	23.1 ± 2.70^b	20.6 ± 2.74^a,B	20.1 ± 2.67^a,A	19.6 ± 2.87^a,A	19.0 ± 2.64^a,A
	MAP	17.6 ± 4.43^d	13.2 ± 4.11^c,B	10.3 ± 3.03^b,A	7.35 ± 2.48^a,A	11.4 ± 3.51^b,c,C	23.1 ± 2.70^b	19.1 ± 2.67^a,A	20.2 ± 2.94^a,A	19.6 ± 2.58^a,A	19.6 ± 2.37^a,A
	Control	17.6 ± 4.43^c	12.2 ± 3.48^b,A,B	8.96 ± 2.63^a,A	8.10 ± 2.60^a,A	7.99 ± 2.20^a,B	23.1 ± 2.70^b	20.5 ± 2.65ª^,B	23.0 ± 2.75^b,B	20.9 ± 2.31^a,A	21.3 ± 1.62^a,B
ΔE*	PE	–	10.4 ± 5.7^a,A	9.4 ± 5.7^a,A	14.5 ± 3.5^b,A	16.1 ± 3.0^b,C	–	5.5 ± 3.0^a,A	6.1 ± 3.9^a,A	6.3 ± 3.7^a,b,A	8.2 ± 2.7^b,A,B
	VAC		10.1 ± 5.3^a,A	12.1 ± 4.1^a,b,A	14.3 ± 3.3^b,A	13.2 ± 3.8^b,A,B		4.8 ± 2.5^a,A	6.2 ± 2.7^a,A	6.4 ± 3.6^a,A	8.7 ± 3.0^b,B
	MAP		8.9 ± 5.4^a,A	11.5 ± 4.3^a,A	16.9 ± 7.6^b,A	10.9 ± 5.8^a,A		6.2 ± 2.9^a,A	5.8 ± 3.3^a,A	6.0 ± 3.0^a,A	7.6 ± 3.2^a,A,B
	Control		9.6 ± 5.1^a,A	11.8 ± 5.8^b,A	13.7 ± 3.4^b,A	14.0 ± 3.3^b,B,C		5.0 ± 2.2^a,A	6.0 ± 4.5^a,A	5.8 ± 2.5^a,A	7.0 ± 2.6^a,A

Values are expressed as Mean ± Standard deviation. Lowercase letters -Values with the same letter in the same line are not statistically different (p˃0.05); Uppercase letters -Values with the same letter in the same column are not statistically different (p˃0.05)

Figure 2. Moisture content and water activity (a_w) of packaged and control chestnuts throughout storage

Figure 3. Titratable acidity and total soluble solids values determined on packaged and control chestnuts along their storage

Table 3. Texture parameters of chestnuts packaged and the control throughout storage

		Storage Time (months)
Texture	Treatment	0	1	2	3	6
Maximum force (N)	PE	33 ± 3ª	34 ± 4^a,A	35 ± 3^a,A	33 ± 3^a,B	33 ± 3^a,B
	VAC	33 ± 3^b,c	34 ± 3^c,A	32 ± 4^b,c,A	31 ± 3^a,b,A	29 ± 4^a,A
	MAP	33 ± 3^b,c	35 ± 3^c,A	34 ± 3^b,c,A	32 ± 5^b,A,B	30 ± 3^a,A
	Control	33 ± 3^a,b	35 ± 3^b,B,A	34 ± 5^a,b,A	32 ± 4^a,b,A,B	32 ± 4^a,B
Elasticity (mm)	PE	2.63 ± 1.26^a	3.97 ± 1.84^b,A	4.03 ± 1.64^b,A	3.89 ± 1.47^b,A	2.99 ± 1.52^a,b,A
	VAC	2.63 ± 1.26^a	3.59 ± 1.57^a,b,A	3.78 ± 1.46^b,A	3.56 ± 1.78^a,b,A	3.74 ± 1.70^a,b,A
	MAP	2.63 ± 1.52^a	3.54 ± 1.74^a,A	4.49 ± 1.44^b,A	3.91 ± 1.60^b,A	4.01 ± 1.65^b,A
	Control	2.63 ± 1.52^a	3.22 ± 1.57^a,b,A	3.74 ± 1.80^b,A	3.40 ± 1.47^a,b,A	3.23 ± 1.38^a,b,A
Hardness (N.sec.)	PE	142 ± 20^a	164 ± 19^c,A	165 ± 16^c,B	158 ± 15^b,c,B	150 ± 14^a,b,B
	VAC	142 ± 20^a,b	162 ± 14^c,A	150 ± 19^b,c,A	144 ± 14^a,b,A	135 ± 19^a,A
	MAP	142 ± 20ª^,b	164 ± 14^c,A	164 ± 16^c,B	149 ± 22^b,A,B	132 ± 17^a,A
	Control	142 ± 20^a	168 ± 14^c,A	159 ± 19^b,c,A,B	147 ± 19^a,b,A	140 ± 16^a,A,B

Values are expressed as Mean ± Standard deviation. Lowercase letters – Values with the same letter in the same line are not statistically different (p˃0.05); Uppercase letters – Values with the same letter in the same column are not statistically different (p˃0.05)

Table 4. Microbial counts in chestnuts packaged in PE, VAC, and MAP and control throughout storage (log CFU/g ± standard deviation)

		Storage Time (months)
Microbial groups	Treatment	0	1	2	3	6
Mesophilic aerobic microorganisms	PE	4.45 ± 0.39^a	4.95 ± 0.56^a,A	4.65 ± 0.42^a,A	4.43 ± 0.19^a,B,C	4.24 ± 0.38^a,B
	VAC	4.45 ± 0.39^b	3.99 ± 0.87ª^,b,A	3.36 ± 0.83^a,b,A	2.83 ± 0.43^a,A	2.69 ± 0.11^a,A
	MAP	4.45 ± 0.39^a	3.60 ± 0.86^a,A	3.51 ± 0.84^a,A	3.45 ± 0.87^a,A,B	2.89 ± 0.68^a,A
	Control	4.45 ± 0.39ª	5.01 ± 0.41^a,A	4.63 ± 0.59^a,A	5.10 ± 0.11^a,C	6.71 ± 0.47^b,C
Molds and yeasts	PE	3.74 ± 0.12^a	4.32 ± 0.20^a,b,A,B	4.50 ± 0.09^a,b,c,A,B	4.64 ± 0.12^b,c,B,C	5.22 ± 0.61^c,A
	VAC	3.74 ± 0.12^b	3.41 ± 0.30ª^,b,A	3.24 ± 0.58^a,b,A	2.83 ± 0.04^a,A	2.72 ± 0.29^a,B
	MAP	3.74 ± 0.12^a	3.22 ± 0.45^a,A	3.35 ± 0.83^a,A	3.54 ± 1.01^a,A,B	3.13 ± 0.34^a,A
	Control	3.74 ± 0.12^a	4.81 ± 0.74^b,B	4.72 ± 0.10^b,B	5.21 ± 0.24^b,C	6.24 ± 0.06^c,C

Values are expressed as Mean ± Standard deviation. Lowercase letters – Values with the same letter in the same line are not statistically different (p˃0.05); Uppercase letters – Values with the same letter in the same column are not statistically different (p˃0.05).