Changes in cuticle compositions and crystal structure of ‘Bingtang’ sweet orange fruits (Citrus sinensis) during storage

Figures & data

Figure 1. Postharvest decay rate (a) and percentage of weight loss (b) of the mature ‘Bingtang’ fruits during storage at 4°C and 25°C for 40 days. Values are the means of three replicates. Different lowercase letters for the same temperature indicate significant differences at the 5% level.

Table 1. Amount of fractions in the cuticle of ‘Bingtang’ fruits during storage at different temperatures.

Fractions	0 day	10 days	20 days	30 days	40 days
	4 °C
Epicuticular wax	1.63^c	1.62^c	3.92^a	4.14^a	2.47^b
Intracuticular wax	8.89^b	9.70^a	8.32^c	8.33^c	6.74^d
Total wax	10.52^c	11.32^b	12.24^a	12.47^a	9.21^d
Cutin	60.70^a	53.82^b	48.40^c	42.21^d	40.63^d
Cuticle	71.22^a	65.14^b	60.64^c	54.68^d	49.84^e
	25 °C
Epicuticular wax	1.63^e	3.20^d	5.19^c	7.62^b	9.79^a
Intracuticular wax	8.89^b	5.17^c	9.36^b	10.06^a	9.37^b
Total wax	10.52^d	8.37^e	14.55^c	17.68^b	19.16^a
Cutin	60.70^c	56.81^d	73.53^b	44.75^e	80.47^a
Cuticle	71.22^c	65.18^d	88.08^b	62.25^e	99.63^a

Fruits were stored at 4°C or 25°C with a relative humidity of 85%. Values are the mean of three replicates of 10 fruits each. The amount of each fraction in the cuticle during storage is expressed as µg cm⁻². Different letters on the same row indicate significant differences at the 5% level.

Table 2. Epicuticular wax constituents of ‘Bingtang’ fruit cuticle during storage at 4^◦C and 25^◦C for 40 days.

Compositions	Harvest	10 days	20 days	30 days	40 days
	Fruits stored at 4 °C (μg cm^−2)
Acids	1.22^c± 0.18	1.24^c± 0.01	2.04^a± 0.22	2.03^a± 0.15	1.42^b± 0.01
Dodecanoic acid	0.04^b± 0.01	0.08^a± 0.01	0.08^a± 0.00	0.08^a± 0.01	0.08^a± 0.01
Tetradecanoic acid	0.03^b± 0.01	0.04^b± 0.00	0.08^a± 0.01	0.06^a± 0.01	0.05^b± 0.01
Pentadecanoic acid	–	–	0.03^b± 0.00	0.06^a± 0.01	0.03^b± 0.00
Hexadecanoic acid	0.79^b± 0.13	0.79^b± 0.01	1.14^a± 0.15	1.05^a± 0.08	0.79^b± 0.04
9,12-Octadecanoic acid	0.02^b± 0.01	0.02^b± 0.00	0.03^ab± 0.01	0.03^ab± 0.01	0.04^a± 0.00
Oleic acid	0.02^b± 0.00	0.02^b± 0.01	0.04^a± 0.00	0.04^ab± 0.01	0.04^a± 0.00
Octadecanoic acid	0.30^b± 0.01	0.26^c± 0.01	0.53^a± 0.05	0.48^a± 0.03	0.30^b± 0.01
Eicosanoic acid	–	–	0.02^b± 0.00	0.03^a± 0.00	0.02^b± 0.00
Docosanoic acid	–	–	–	0.04^a± 0.00	0.02^b± 0.00
Tetracosanoic acid	0.02^e± 0.00	0.03^d± 0.01	0.09^b± 0.01	0.16^a± 0.01	0.05^c± 0.00
Alkanes	0.29^d± 0.02	0.31^d± 0.01	1.32^b± 0.02	1.44^a± 0.01	0.75^c± 0.01
Heptadecane	0.03^a± 0.00	0.04^a± 0.03	0.03^a± 0.01	0.03^a± 0.00	0.03^a± 0.00
Octadecane	–	–	–	0.02^a± 0.00	0.02^a± 0.00
Tricosane	0.0^c± 0.01	0.07^b± 0.02	0.09^b± 0.00	0.12^a± 0.01	0.11^a± 0.00
Pentacosane	0.04^c± 0.01	0.07^bc± 0.02	0.10^b± 0.01	0.14^a± 0.00	0.11^b± 0.01
Hexacosane	0.02^a± 0.01	0.02^a± 0.00	0.03^a± 0.01	0.03^a± 0.01	0.03^a± 0.00
Heptacosane	0.06^c± 0.01	0.02^d± 0.00	0.20^a± 0.01	0.19^a± 0.01	0.10^b± 0.01
Nonacosane	0.06^c± 0.01	0.02^d± 0.01	0.73^a± 0.03	0.73^a± 0.02	0.28^b± 0.00
Hentriacontane	0.05^c± 0.01	0.07^c± 0.02	0.14^b± 0.01	0.18^a± 0.00	0.07^c± 0.01
Alcohols	0.07^d± 0.01	0.03^e± 0.01	0.15^b± 0.01	0.24^a± 0.01	0.10^c± 0.01
13-Docosen-1-ol	0.07^d± 0.01	0.03^e± 0.01	0.15^b± 0.01	0.24^a± 0.01	0.10^c± 0.01
Terpenoids	0.02^e± 0.00	0.04^d± 0.01	0.33^b± 0.01	0.37^a± 0.01	0.17^c± 0.00
Squalene	–	0.02^c± 0.01	0.27^a± 0.02	0.28^a± 0.01	0.14^b± 0.00
Friedanlan	0.02^d± 0.00	0.02^d± 0.00	0.06^b± 0.01	0.09^a± 0.00	0.03^c± 0.00
	Fruits stored at 25 °C (μg cm^−2)
Acids	1.22^c± 0.18	1.52^c± 0.26	2.15^b± 0.11	2.98^a± 0.18	2.83^a± 0.03
Dodecanoic acid	0.04^c± 0.01	0.08^b± 0.00	0.08^b± 0.00	0.08^b± 0.01	0.10^a± 0.00
Tetradecanoic acid	0.03^b± 0.01	0.03^b± 0.01	0.05^b± 0.01	0.08^a± 0.01	0.07^ab± 0.01
Pentadecanoic acid	–	–	–	–	0.02 ± 0.00
Hexadecanoic acid	0.79^ab± 0.13	0.95^a± 0.17	0.76^ab± 0.11	0.74^ab± 0.08	0.71^b± 0.04
9,12-Octadecanoic acid	0.02^c± 0.01	0.03^bc± 0.01	0.05^b± 0.01	0.04^b± 0.01	0.08^a± 0.00
Oleic acid	0.02^c± 0.00	0.02^c± 0.01	0.05^b± 0.01	0.05^b± 0.01	0.08^a± 0.00
Octadecanoic acid	0.30^c± 0.01	0.38^b± 0.05	0.45^ab± 0.02	0.46^ab± 0.05	0.47^a± 0.04
Eicosanoic acid	–	–	–	–	0.07 ± 0.00
Docosanoic acid	–	–	0.06^c± 0.00	0.10^b± 0.01	0.13^a± 0.00
Tetracosanoic acid	0.02^d± 0.00	0.03^d± 0.01	0.65^c± 0.05	1.43^a± 0.10	1.10^b± 0.04
Alkanes	0.29^e± 0.02	1.24^d± 0.01	1.48^c± 0.01	1.87^b± 0.01	2.37^a± 0.01
Heptadecane	0.03^a± 0.00	0.03^ab± 0.01	0.03^ab± 0.01	0.02^ab± 0.01	0.02^b± 0.00
Octadecane	–	–	0.01^a± 0.01	0.02^a± 0.00	0.02^a± 0.00
Tricosane	0.03^e± 0.01	0.76^a± 0.01	0.06^d± 0.00	0.12^c± 0.01	0.19^b± 0.01
Pentacosane	0.04^d± 0.01	0.05^d± 0.01	0.11^c± 0.01	0.20^b± 0.01	0.26^a± 0.01
Hexacosane	0.02^c± 0.01	0.03^bc± 0.01	0.05^b± 0.01	0.12^a± 0.01	0.05^b± 0.01
Heptacosane	0.06^e± 0.01	0.12^d± 0.01	0.28^c± 0.01	0.45^b± 0.01	0.58^a± 0.02
Nonacosane	0.06^d± 0.01	0.17^c± 0.01	0.58^b± 0.03	0.63^b± 0.04	0.85^a± 0.03
Hentriacontane	0.05^c± 0.01	0.08^b± 0.01	0.35^a± 0.03	0.31^a± 0.02	0.4^c± 0.01
Alcohols	0.07^c± 0.01	0.11^c± 0.06	0.57^b± 0.02	1.34^a± 0.09	1.23^a± 0.02
13-Docosen-1-ol	0.07^c± 0.01	0.11^c± 0.06	0.57^b± 0.02	1.34^a± 0.09	1.23^a± 0.02
Terpenoids	0.02^e± 0.00	0.31^d± 0.01	0.94^c± 0.02	1.17^b± 0.02	3.21^a± 0.03
Squalene	–	0.24^c± 0.02	0.81^b± 0.05	0.87^b± 0.04	2.87^a± 0.08
Friedanlan	0.02^d± 0.00	0.07^c± 0.01	0.13^b± 0.01	0.30^a± 0.05	0.34^a± 0.02

Values are the means of three replicates of 10 fruits each. Mean values in the same row for different storage times at the same temperature with different superscripts are significantly different (p < 0.05);–: not detected.

Figure 2. Proportion of components in the epicuticular wax of ‘Bingtang’ fruits during storage at 4°C and 25°C for 40 days.

Table 3. Intracuticular wax constituents of ‘Bingtang’ fruit cuticle during storage at 4^◦C and 25^◦C for 40 days.

Compositions	Harvest	10 days	20 days	30 days	40 days
	Fruits stored at 4 °C (μg cm^−2)
Acids	3.48^b± 0.08	5.43^a± 0.13	3.02^c± 0.01	2.76^e± 0.03	2.83^d± 0.02
Tetradecanoic acid	0.16^b± 0.01	0.13^bc± 0.04	0.18^b± 0.01	0.26^a± 0.01	0.10^c± 0.01
cis-9-Hexadecenoic acid	–	–	0.09^a± 0.01	0.04^b± 0.01	0.04^b± 0.01
Hexadecanoic acid	0.86^b± 0.01	2.06^a± 0.06	0.85^b± 0.02	0.86^b± 0.10	0.82^b± 0.05
9,12-Octadecanoic acid	0.09^c± 0.01	0.12^b± 0.01	0.11^bc± 0.01	0.17^a± 0.01	0.12^b± 0.01
Oleic acid	0.19^b± 0.00	0.15^c± 0.02	0.22^a± 0.01	0.20^a± 0.01	0.20^a± 0.02
Octadecanoic acid	0.15^d± 0.01	1.66^a± 0.07	0.34^c± 0.01	0.43^b± 0.01	0.34^c± 0.01
Eicosanoic acid	–	–	0.05^b± 0.01	0.09^a± 0.01	0.06^b± 0.01
Docosanoic acid	0.09^a± 0.01	0.19^a± 0.11	0.06^b± 0.01	0.11^a± 0.01	0.07^ab± 0.01
Tetracosanoic acid	1.78^a± 0.10	1.06^c± 0.11	1.12^b± 0.01	0.60^d± 0.02	1.08^c± 0.02
Alkanes	1.30^b± 0.03	0.87^e± 0.01	0.91^d± 0.01	1.42^a± 0.02	1.00^c± 0.01
Heneicosane	–	–	0.06^b± 0.01	0.15^a± 0.01	0.03^c± 0.01
Tricosane	0.14^d± 0.01	0.17^c± 0.01	0.15^cd± 0.01	0.27^a± 0.01	0.24^b± 0.01
Pentacosane	0.17^b± 0.01	0.17^b± 0.01	0.15^b± 0.01	0.04^c± 0.01	0.21^a± 0.01
Hexacosane	–	–	0.03^ab± 0.01	0.05^a± 0.01	0.02^b± 0.01
Heptacosane	0.29^a± 0.01	0.20b± 0.01	0.14b± 0.06	0.29^a± 0.01	0.14b± 0.06
Nonacosane	0.40^a± 0.02	0.21^c± 0.01	0.23^c± 0.01	0.35^b± 0.02	0.22^c± 0.01
Hentriacontane	0.29^a± 0.02	0.12^c± 0.01	0.15^b± 0.01	0.27^a± 0.02	0.14^bc± 0.01
Alcohols	1.74^b± 0.13	1.32^c± 0.02	1.24^d± 0.01	1.92^a± 0.01	1.31^c± 0.01
13-Docosen-1-ol	1.74^a± 0.13	1.32^b± 0.02	1.19^c± 0.01	1.81^a± 0.03	1.29^b± 0.01
Tetracosan-1-ol	–	–	0.05^b± 0.01	0.11^a± 0.01	0.02^c± 0.00
Terpenoids	2.28^b± 0.30	2.00^b± 0.08	2.94^a± 0.20	1.96^b± 0.07	1.32^c± 0.01
Farnesol	0.04^b± 0.01	0.60^a± 0.05	0.60^a± 0.04	0.05^ab± 0.01	0.02^b± 0.01
Squalene	0.55^c± 0.01	0.36^e± 0.01	0.89^a± 0.04	0.59^b± 0.02	0.45^d± 0.01
Campesterol	–	0.08^a± 0.01	0.02^b± 0.01	0.03^b± 0.01	0.02^b± 0.01
Stigmasterol	–	0.02^ab± 0.01	0.02^ab± 0.01	0.03^a± 0.01	0.01^b± 0.00
Lup-20(29)-en-3-one	0.22^a± 0.03	0.14^b± 0.01	0.19^a± 0.01	0.18^a± 0.01	0.12^b± 0.01
β-Amyrin	0.47^a± 0.06	0.27^c± 0.01	0.44^ab± 0.03	0.37^b± 0.04	0.23^d± 0.01
Urs-12-en-24-oic acid	0.08^a± 0.02	0.05^ab± 0.01	0.07^a± 0.01	0.07^a± 0.01	0.04^b± 0.01
Friedanlan	0.91^a± 0.17	0.48^c± 0.02	0.71^ab± 0.05	0.67^b± 0.04	0.43^d± 0.01
	Fruits stored at 25 °C (μg cm^−2)
Acids	3.48^a± 0.08	1.34^d± 0.25	3.47^a± 0.02	3.10^b± 0.03	2.50^c± 0.02
Tetradecanoic acid	0.16^b± 0.01	0.04^d± 0.01	0.29^a± 0.01	0.13^c± 0.01	0.12^c± 0.01
Pentadecanoic acid	–	–	–	–	0.03 ± 0.01
cis-9-Hexadecenoic acid	–	–	–	0.05^a± 0.01	0.05^a± 0.01
Hexadecanoic acid	0.86^b± 0.01	0.05^e± 0.03	1.12^a± 0.04	0.67^c± 0.04	0.47^d± 0.03
9,12-Octadecanoic acid	0.09^b± 0.01	0.05^c± 0.01	0.22^a± 0.01	0.10^b± 0.01	0.11^b± 0.01
Oleic acid	0.19^b± 0.00	0.02^d± 0.01	0.35^a± 0.02	0.15^c± 0.00	0.16^c± 0.01
Octadecanoic acid	0.15^d± 0.01	0.03^e± 0.02	0.54^a± 0.02	0.45^b± 0.03	0.27^c± 0.02
Eicosanoic acid	–	–	0.11^a± 0.01	0.05^b± 0.01	0.06^b± 0.01
Docosanoic acid	0.09^b± 0.01	0.09^b± 0.01	0.11^b± 0.01	0.12^ab± 0.01	0.14^a± 0.01
Tetracosanoic acid	1.78^a± 0.10	1.06^c± 0.16	0.73^d± 0.01	1.38^b± 0.07	1.09^c± 0.04
Alkanes	1.30^b± 0.03	0.82^d± 0.03	1.17^c± 0.04	1.74^a± 0.06	1.69^a± 0.02
Heneicosane	–	0.02^c± 0.01	0.11^a± 0.01	0.05^b± 0.01	0.04^bc± 0.01
Tricosane	0.14^a± 0.01	0.09^b± 0.01	0.17^a± 0.03	0.10^b± 0.01	0.14^a± 0.01
Pentacosane	0.17^a± 0.01	0.11^b± 0.01	0.19^a± 0.03	0.13^b± 0.01	0.16^a± 0.01
Hexacosane	–	–	–	–	0.02 ± 0.00
Heptacosane	0.29^b± 0.01	0.20^c± 0.03	0.27^b± 0.01	0.34^a± 0.02	0.36^a± 0.01
Nonacosane	0.40^c± 0.02	0.28^d± 0.05	0.30^d± 0.01	0.73^a± 0.05	0.63^b± 0.04
Hentriacontane	0.29^b± 0.02	0.12^c± 0.02	0.13^c± 0.01	0.39^a± 0.04	0.34^ab± 0.04
Alcohols	1.74^a± 0.13	1.19^c± 0.18	1.00^d± 0.05	1.45^b± 0.01	1.30^c± 0.04
13-Docosen-1-ol	1.74^a± 0.13	1.19^cd± 0.18	1.00^d± 0.05	1.45^b± 0.01	1.30^c± 0.04
Tetracosan-1-ol	–	–	–	–	–
Terpenoids	2.28^b± 0.30	1.81^b± 0.29	3.27^a± 0.09	3.51^a± 0.23	3.63^a± 0.34
Farnesol	0.04^c± 0.01	0.05^c± 0.01	0.14^a± 0.01	0.07^bc± 0.01	0.09^b± 0.01
Squalene	0.55^d± 0.01	0.77^c± 0.10	2.17^a± 0.10	1.40^b± 0.09	2.37^a± 0.20
Campesterol	–	–	–	0.07^a± 0.01	0.03^b± 0.01
Stigmasterol	–	–	–	0.03^a± 0.01	0.02^a± 0.01
Lup-20(29)-en-3-one	0.22^b± 0.03	0.16^bc± 0.11	0.15^c± 0.01	0.32^a± 0.10	0.19^b± 0.02
β-Amyrin	0.47^a± 0.06	0.20^c± 0.02	0.31^b± 0.03	0.38^ab± 0.05	0.24^c± 0.02
Urs-12-en-24-oic acid	0.08^ab± 0.02	0.07^b± 0.01	0.06^b± 0.01	0.10^a± 0.01	0.05^b± 0.01
Friedanlan	0.91^ab± 0.17	0.56^b± 0.04	0.44^c± 0.04	1.14^a± 0.15	0.64^b± 0.07

Values are the means of three replicates of 10 fruits each. Mean values in the same row for different storage times at the same temperature with different superscripts are significantly different (p < 0.05);–: not detected.

Figure 3. Proportion of components in the epicuticular wax of ‘Bingtang’ fruit cuticle during storage at 4°C and 25°C for 40 days. The x-axis scales represent the days of storage.

Table 4. Cutin monomer composition of ‘Bingtang’ fruits during storage at 4^◦C and 25^◦C for 40 days.

Compositions	Harvest	10 days	20 days	30 days	40 days
	Fruits stored at 4 °C (μg cm^−2)
Cinnamic acid	15.91^a± 0.26	12.93^b± 0.20	13.14^b± 0.20	11.20^c± 0.53	11.01^c± 0.20
Pentadecanoic acid	2.40^a± 0.00	2.05^a± 0.06	2.14^a± 0.02	2.53^a± 0.29	1.13^b± 0.03
Hexadecanoic acid	4.92^c± 0.21	5.63^b± 0.31	4.43^c± 0.51	7.52^a± 0.57	7.45^a± 0.77
Hexadecanedioic acid	2.90^b± 0.05	2.76^c± 0.14	3.18^a± 0.05	2.01^d± 0.17	1.94^d± 0.02
cis-9-Hexadecenoic acid	20.10^a± 0.31	18.23^b± 0.38	21.12^c± 0.27	14.94^d± 0.17	12.73^e± 0.06
Octadecanoic acid	3.25^b± 0.31	3.60^b± 0.07	2.54^c± 0.24	2.28^c± 0.29	4.72^a± 0.26
Octadecanedioic acid	7.71^a± 0.14	5.54^b± 0.09	–	–	–
Docosanoic acid	1.54^a± 0.00	1.28^b± 0.11	–	–	–
Trtracosanoic acid	–	–	–	–	–
Phenol	1.95^a± 0.40	2.14^a± 0.22	2.23^a± 0.22	1.91^a± 0.17	1.80^a± 0.26
	Fruits stored at 25 °C (μg cm^−2)
Cinnamic acid	15.91^b± 0.26	16.20^b± 0.74	12.24^c± 0.17	7.70^d± 0.08	18.04^a± 0.58
Pentadecanoic acid	2.42^c± 0.00	2.54^c± 0.08	3.03^b± 0.05	1.58^d± 0.05	3.26^a± 0.05
Hexadecanoic acid	4.94^d± 0.21	5.23^c± 0.05	8.93^a± 0.33	6.29^b± 0.93	6.51^b± 0.38
Hexadecanedioic acid	2.93^c± 0.05	3.18^b± 0.16	4.60^a± 0.08	2.21^d± 0.05	4.50^a± 0.17
cis-9-Hexadecenoic acid	20.18^b± 0.31	20.35^b± 0.26	26.28^a± 0.52	14.78^c± 0.17	26.21^a± 0.41
Octadecanoic acid	3.25^c± 0.31	3.16^c± 0.16	4.89^a± 0.12	4.00^b± 0.49	4.09^b± 0.29
Octadecanedioic acid	7.76^c± 0.14	2.23^e± 0.05	10.19^b± 0.17	7.09^d± 0.09	14.63^a± 0.19
Docosanoic acid	1.52^b± 0.00	1.54^b± 0.00	1.61^a± 0.05	–	–
Trtracosanoic acid	–	–	–	–	1.00 ± 0.19
Phenol	1.94^b± 0.40	2.73^a± 0.22	1.79^b± 0.39	1.31^b± 0.14	2.23^a± 0.33

Values are the means of three replicates of 10 fruits each. Mean values in the same row for different storage times at the same temperature with different superscripts are significantly different (p < 0.05);–: not detected.

Figure 4. Proportion of cutin components of ‘Bingtang’ fruits during storage at 4°C and 25°C for 40 days.

Figure 5. Epicuticular wax crystal structure of ‘Bingtang’ fruits during storage for 40 days as imaged at ×400 and ×1500 magnifications. (a): Samples at harvest. (b–e): Samples stored at 4°C from 10 to 40 days. (f–i): Samples stored at 25°C from 10 to 40 days.