Composition, Color and Mechanical Characteristics of Pretreated Candied Chestnuts

Figures & data

Figure 1 Temperature profile for retort and chestnut sample during steaming.

Table 1 Composition of the candied chestnuts for three different treatments at each processing step.

		Proximate analyses results
Treatments	Processing steps	Moisture content(%)	Protein content(%)	Lipid content(%)	Ash content(%)	Carbohydrate content(%)
Control	Raw chestnuts	55.09 ± 2.24 ^b	2.33 ± 0.37 ^a	1.30 ± 0.17 ^a	2.46 ± 0.30 ^a	38.82
	1 h in water	57.65 ± 1.95 ^ab	1.81 ± 0.22 ^b	1.14 ± 0.43 ^a	2.46 ± 0.35 ^a	36.94
	Steamed chestnuts	59.08 ± 3.02 ^a	1.86 ± 0.27 ^b	1.29 ± 0.43 ^a	2.00 ± 0.02 ^b	35.77
	Dipping into Sucrose	23.69 ± 2.19 ^c	1.34 ± 0.24 ^c	0.78 ± 0.55 ^b	0.71 ± 0.06 ^c	73.48
	Sugar Solution Fructose	21.82 ± 2.54 ^c	1.35 ± 0.03 ^c	0.47 ± 0.04 ^b	0.75 ± 0.07 ^c	75.61
CA	Raw chestnuts	55.09 ± 2.24 ^b	2.33 ± 0.37 ^a	1.30 ± 0.17 ^a	2.46 ± 0.30 ^a	38.82
	1 h in CA	56.10 ± 0.64 ^b	1.96 ± 0.03 ^b	1.10 ± 0.39 ^ab	2.17 ± 0.20 ^b	38.67
	Steamed chestnuts	60.58 ± 2.21 ^a	1.91 ± 0.10 ^b	0.91 ± 0.39 ^b	2.23 ± 0.11 ^ab	34.37
	Dipping into Sucrose	23.90 ± 2.87 ^c	1.35 ± 0.13 ^c	0.32 ± 0.05 ^c	0.71 ± 0.06 ^c	73.72
	Sugar Solution Fructose	22.07 ± 2.23 ^c	1.35 ± 0.06 ^c	0.29 ± 0.05 ^c	0.70 ± 0.18 ^c	75.59
MS	Raw chestnuts	55.09 ± 2.24 ^b	2.33 ± 0.37 ^a	1.30 ± 0.17 ^a	2.46 ± 0.30 ^ab	38.82
	1 h in MS	56.34 ± 1.73 ^ab	1.98 ± 0.08 ^b	1.19 ± 0.52 ^a	2.45 ± 0.07 ^a	38.04
	Steamed chestnuts	58.64 ± 2.40 ^a	1.75 ± 0.01 ^b	0.92 ± 0.13 ^a	2.26 ± 0.16 ^b	36.43
	Dipping into Sucrose	23.15 ± 2.25 ^c	1.31 ± 0.04 ^c	0.30 ± 0.00 ^b	0.79 ± 0.04 ^c	74.45
	Sugar Solution Fructose	21.29 ± 3.12 ^c	1.33 ± 0.06 ^c	0.57 ± 0.29 ^b	0.68 ± 0.07 ^c	76.13
CA: Citric acid; MS: Sodium metabisulfite; ^a–c: Different letters in each column within each treatment denote significant difference at the p < 0.05; Data are mean values ± S.D.

Figure 2 Weight change of the candied chestnuts dipped into sucrose solution (a) and fructose solution (b) during processing.

Table 2 The concentration of elements in the chestnut samples for three different treatments during candied chestnut processing.

		Mineral contents (mg/100 g sample)
Treatments	Processing steps	Ca	Cu	Fe	K	Mg	Mn	Zn
Control	Raw chestnuts	39.00 ± 0.20 ^b	0.48 ± 0.16 ^a	1.24 ± 0.13 ^bc	659.1 ± 292.7 ^a	69.57 ± 1.51 ^a	1.69 ± 0.18 ^a	1.98 ± 0.02
	1 h in water	46.70 ± 0.79 ^a	0.48 ± 0.01 ^a	1.98 ± 0.51 ^a	556.0 ± 6.57 ^ab	68.38 ± 1.48 ^a	1.86 ± 0.33 ^a	2.12 ± 0.02
	Steamed chestnuts	40.11 ± 4.64 ^ab	0.45 ± 0.00 ^a	1.75 ± 0.03 ^ab	485.2 ± 19.7 ^ab	66.71 ± 2.08 ^a	1.63 ± 0.48 ^a	6.95 ± 4.09
	Dipping into Sucrose	19.08 ± 2.56 ^c	0.21 ± 0.00 ^b	0.88 ± 0.06 ^c	180.5 ± 16.1 ^a	26.83 ± 1.26 ^b	0.84 ± 0.26 ^b	2.61 ± 0.21
	Sugar Solution Fructose	21.88 ± 2.81 ^c	0.25 ± 0.06 ^b	0.95 ± 0.01 ^c	288.3 ± 159.8 ^ab	33.12 ± 6.09 ^b	0.76 ± 0.02 ^b	2.01 ± 1.21
CA	Raw chestnuts	39.00 ± 0.20 ^a	0.48 ± 0.16 ^a	1.25 ± 0.13	659.1 ± 292.7 ^a	69.57 ± 1.51 ^a	1.69 ± 0.18 ^a	1.98 ± 0.02
	1 h in CA	38.13 ± 6.18 ^a	0.52 ± 0.02 ^a	1.52 ± 0.62	627.1 ± 166.1 ^ab	72.07 ± 2.48 ^a	1.96 ± 1.36	6.02 ± 4.08
	Steamed chestnuts	34.95 ± 2.19 ^a	0.40 ± 0.01 ^ab	1.39 ± 0.11	600.9 ± 157.3 ^ab	66.95 ± 0.52 ^a	1.72 ± 0.06	6.95 ± 4.56
	Dipping into Sucrose	20.23 ± 3.52 ^b	0.19 ± 0.02 ^b	1.01 ± 0.21	228.0 ± 52.0 ^ab	30.64 ± 4.42 ^b	0.77 ± 0.24	4.25 ± 2.44
	Sugar Solution Fructose	23.59 ± 6.21 ^b	0.30 ± 0.09 ^ab	1.22 ± 0.32	198.8 ± 67.8 ^ab	30.87 ± 2.25 ^b	0.70 ± 0.15	2.87 ± 0.50
MS	Raw chestnuts	39.00 ± 0.20 ^ab	0.48 ± 0.16	1.25 ± 0.13	659.1 ± 292.7 ^a	69.57 ± 1.51 ^a	1.69 ± 0.18 ^ab	1.98 ± 0.02
	1 h in MS	37.28 ± 0.36 ^ab	0.49 ± 0.07	1.45 ± 0.05	455.1 ± 69.4 ^ab	67.37 ± 1.60 ^a	1.54 ± 0.48 ^ab	2.13 ± 0.39
	Steamed chestnuts	45.91 ± 2.68 ^a	0.38 ± 0.17	1.83 ± 0.18	599.0 ± 161.3 ^ab	71.57 ± 3.38 ^a	2.42 ± 0.24 ^a	2.43 ± 0.39
	Dipping into Sucrose	21.43 ± 2.52 ^b	0.21 ± 0.02	0.95 ± 0.01	212.9 ± 62.2 ^b	34.71 ± 0.07 ^b	0.93 ± 0.01 ^b	1.51 ± 0.37
	Sugar Solution Fructose	22.93 ± 1.68 ^b	0.39 ± 0.19	0.95 ± 0.03	231.5 ± 127.6 ^ab	34.18 ± 4.54 ^b	1.08 ± 0.17 ^b	2.55 ± 0.55
CA: Citric acid; MS: Sodium metabisulfite; ^a–c: Different letters in each column within each treatment denote significant difference at the p < 0.05; Data are mean values ± S.D; Spike recovery values of the chestnuts were: Ca 108 ± 24.0 %; Cu 95 ± 5.0%; Fe 116 ± 5.0%; K 107 ± 4.0%; Mg 107 ± 4.0%; Mn 88 ± 20.0; Zn 105 ± 22.0%.

Figure 3 Change of compression in candied chestnut samples treated with distilled water, citric acid, or sodium metabisulphite during processing.

Table 3 Color spectra for candied chestnuts treated with distilled water, citric acid (CA), and sodium metabisulphite (MS) and dipped into sucrose or fructose solutions during processing. Only colors higher than 3% of the total area were considered.

		Colors (% of the total area)
Treatment	Processing steps	Dark yellow	Moderate olive brown	Moderate olive	Moderate brown	Deep yellowish brown	Dark brown	Deep reddish brown and deep brown
Control	Raw	12.533	17.924	2.550	4.183	2.712	0.840	0.117
	1 h in water	13.099	16.768	7.434	6.230	2.109	1.393	0.173
	Steamed	1.292	7.606	0.981	4.969	25.588	14.251	6.337
	Sucrose	0.035	0.834	0.238	1.738	4.821	23.365	18.349
	Raw	11.758	17.811	2.150	4.898	2.229	0.355	0.056
	1 h in water	9.108	14.334	8.238	9.354	1.161	0.729	0.040
	Steamed	0.782	9.831	1.666	5.058	24.424	18.348	5.906
	Fructose	0.004	0.174	0.083	0.801	6.330	26.400	8.842
CA	Raw	10.339	29.732	3.559	4.213	7.300	1.641	0.289
	1 h in CA	12.083	16.232	6.056	7.722	1.600	0.715	0.059
	Steamed	0.882	10.049	1.618	4.917	28.232	14.128	5.985
	Sucrose	0.019	0.613	0.151	1.107	5.323	27.303	15.971
	Raw	12.272	25.448	2.460	4.846	5.124	1.685	0.204
	1 h in CA	12.536	17.881	6.510	6.206	2.480	0.824	0.065
	Steamed	0.281	6.212	1.141	3.782	23.742	21.827	12.583
	Fructose	0.003	0.250	0.060	0.664	4.520	21.334	10.410
MS	Raw	8.461	31.497	4.443	5.314	8.194	2.739	0.311
	1 h in MS	13.971	19.387	6.802	6.609	2.375	0.883	0.065
	Steamed	0.126	9.754	1.101	3.588	29.905	16.147	6.903
	Sucrose	0.002	0.694	0.067	1.354	6.031	27.812	17.710
	Raw	7.562	32.220	4.143	5.894	8.326	4.027	0.788
	1 h in MS	13.057	17.563	6.551	8.663	1.370	1.064	0.025
	Steamed	0.955	8.837	1.098	4.643	28.075	16.216	6.595
	Fructose	0.001	0.386	0.160	0.221	7.197	23.813	19.248

Figure 4 L*, a* and b* values of candied chestnuts dipped into sucrose solution (a) or fructose solution (b) during processing.