Antioxidant profile of thinned young and ripe fruits of Chinese peach and nectarine varieties

Figures & data

Table 1. Fruit quality indices of peach and nectarine.

Cultivars	Collection date	Weight (g)	Volume (mL)	FSI	Peel hardness (N)	Flesh hardness (N)	pH	TA (%)	SSC (^°Brix)	SSC/TA
TN1	15 May	11.6 ± 1.4 ^g	16.6 ± 1.8 ^f	1.1 ± 0.1 ^cd	17.7 ± 2.0^ab	7.8 ± 1.1^d	3.7 ± 0.01 ^k	0.8 ± 0.02^a	9.5 ± 0.1^de	11.3 ± 0.2 ^h
TN2	15 May	10.2 ± 1.0 ^g	15.5 ± 1.1 ^f	1.2 ± 0.1^bc	16.0 ± 1.6^bc	9.9 ± 1.6^bc	3.8 ± 0.01 ^j	0.7 ± 0.01 ^c	8.9 ± 0.1 ^gh	13.4 ± 0.2 ^g
TN3	15 May	9.7 ± 1.7 ^g	14.5 ± 2.0 ^f	1.3 ± 0.1^ab	14.8 ± 1.8 ^c	9.4 ± 0.5 ^c	3.8 ± 0^i	0.6 ± 0.01^d	8.7 ± 0 ^h	13.9 ± 0.3 ^g
TN4	15 May	9.8 ± 1.0 ^g	14.3 ± 1.0 ^f	1.4 ± 0^a	15.6 ± 1.7 ^c	8.4 ± 1.0^d	3.8 ± 0.01^i	0.7 ± 0.01^b	9.5 ± 0.1^de	13.1 ± 0.2 ^g
TP1	15 May	9.4 ± 1.4 ^g	13.7 ± 2.1 ^f	0.6 ± 0 ^g	18.5 ± 2.9^a	11.8 ± 1.5^a	3.9 ± 0.00 ^h	0.7 ± 0.03 ^c	9.6 ± 0.1 ^cd	14.1 ± 0.5 ^g
TP2	17 May	11.6 ± 1. 9 ^g	16.9 ± 2.6 ^f	1.3 ± 0^b	15.4 ± 2.2 ^c	10.5 ± 1.8^b	3.9 ± 0.01 ^h	0.6 ± 0.02^d	8.7 ± 0 ^h	14.1 ± 0.5 ^g
TP3	17 May	11.0 ± 2.2 ^g	15.8 ± 2.4 ^f	1.2 ± 0.1^bc	14.5 ± 3.5 ^c	10.6 ± 1.4^b	4.0 ± 0.01 ^f	0.5 ± 0.01^e	9.2 ± 0.1e^f	17.3 ± 0.2 ^f
RN1	18 Jun.	101.0 ± 13.8 ^f	104.3 ± 14.8^e	1.0 ± 0.1^de	5.4 ± 1.7 ^f	1.0 ± 0.6 ^g	4.6 ± 0.01 ^c	0.2 ± 0^i	12.3 ± 0.1^a	65.0 ± 0.1^b
RN2	25 Jul.	182.1 ± 23.7^e	187.7 ± 24.8^d	1.0 ± 0.1^de	8.2 ± 1.4^e	2.1 ± 0.8 ^f	4.1 ± 0.01 ^f	0.5 ± 0 ^f	9.3 ± 0.1 ^h	17.7 ± 0.2 ^f
RN3	25 Jul.	252.6 ± 21.4 ^c	257.5 ± 22.3^b	1.0 ± 0.1^de	5.0 ± 1.9 ^f	0.7 ± 0.4 ^g	4.2 ± 0.02^e	0.4 ± 0 ^g	9.0 ± 0.1^fg	23.3 ± 0.1^e
RN4	10 Aug.	215.1 ± 18.7^d	222.1 ± 20.1 ^c	0.9 ± 0.1^ef	10.0 ± 1.1^d	3.4 ± 0.2^e	4.0 ± 0.01 ^g	0.5 ± 0.01^ef	9.7 ± 0.1 ^c	18.9 ± 0.3 ^f
RP1	20 Jul.	170.5 ± 21.6^e	183.6 ± 22.2^d	0.5 ± 0 ^h	7.3 ± 1.6^e	2.0 ± 1.0 ^f	4.9 ± 0.02^a	0.1 ± 0 ^j	9.7 ± 0.1 ^c	77.9 ± 0.4^a
RP2	15 Aug.	320.1 ± 19.2^a	330.1 ± 20.4^a	1.0 ± 0.1^de	4.3 ± 1.0 ^f	0.6 ± 0.1 ^g	4.5 ± 0^d	0.2 ± 0^i	9.3 ± 0.2^de	48.4 ± 0.5 ^c
RP3	4 Sep.	303.9 ± 27.1^b	319.1 ± 28.4^a	0.9 ± 0 ^f	7.8 ± 1.2^e	3.3 ± 0.2^e	4.7 ± 0^b	0.2 ± 0.01 ^h	10.7 ± 0.4^b	45.1 ± 0.3^d

TN1–thinned nectarine “Xiazhizaohong”, RN1–ripe nectarine “Xiazhizaohong”; TN2–thinned nectarine “Ruiguang35”, RN2–ripe nectarine “Ruiguang35”; TN3–thinned nectarine “98-6-54”, RN3–ripe nectarine “98-6-54”; TN4–thinned nectarine “98-6-21”, RN4–ripe nectarine “98-6-21”; TP1–thinned peach “2000-7-1east”, RP1–ripe peach “2000-7-1east”; TP2 – thinned peach “Guibao98-6-48”, RP2–ripe peach “Guibao98-6-48”; TP3 – thinned peach “94-2-12”, RP3–ripe peach “94-2-12”.

FSI: fruit shape index; TA: titratable acidity; SSC: soluble solids content. The values of weight, volume, FSI, peel hardness and flesh hardness are measured ten times and expressed as means ± standard (n = 10), while values of pH, TA, SSC, and SSC/TA are expressed as means ± standard (n = 3). Different letters in the column indicate significant differences at *P < 0.05.

Figure 1. Appearance characteristics of thinned young and ripe fruit of 7 Chinese peaches and nectarines.

(a): Xiazhizaohong; (b): Ruiguang35; (c): 98-6-54; (d): 98-6-21; (e): 2000-7-1 east; (f): Guibao98-6-48; (g): 94-2-12.

Table 2. Individual polyphenols in thinned and ripe peach and nectarine (mg/kg).

	Neochlorogenic acid	Catechin	Chlorogenic acid	Quercitrin	Hyperoside	Rutin
TN1	660.2 ± 7.4^d	329.2 ± 3.6^d	287.8 ± 4.1^d	17.8 ± 1.2 ^c	34.1 ± 0.1^a	62.6 ± 0.5^a
TN2	922.8 ± 1.7^b	475.3 ± 1.1 ^c	501.5 ± 1.8^a	14.5 ± 1.7 ^c	36.2 ± 0.1^a	40.8 ± 0.4 ^c
TN3	1254.5 ± 3.6^a	1169.7 ± 8.3^a	373.8 ± 3.6^b	23.3 ± 3.0^b	27.9 ± 1.0^b	34.8 ± 1.6^d
TN4	664.9 ± 7.1^d	336.9 ± 4.8^d	294.2 ± 3.3 ^c	15.5 ± 1.8 ^c	34.5 ± 1.5^a	55.3 ± 0.4^b
TP1	272.4 ± 0.2 ^f	193.7 ± 1.8^e	121.4 ± 0.2 ^g	45.7 ± 2.5^a	12.0 ± 1.7 ^c	6.2 ± 3.5^ij
TP2	494.8 ± 3.3^e	313.0 ± 2.3^d	171.2 ± 1.3 ^f	21.4 ± 3.2^b	7.0 ± 0.1^d	9.1 ± 0.2^i
TP3	764.0 ± 2.0 ^c	706.3 ± 15.9^b	214.2 ± 1.1^e	24.5 ± 4.1^b	8.4 ± 0.7^d	4.7 ± 2.1 ^j
RN1	44.7 ± 2.6^i	27.6 ± 0.3^i	39.8 ± 0.1^ij	6.2 ± 0.1^d	1.4 ± 0.2^e	27.8 ± 0.1^e
RN2	47.2 ± 0.3^i	36.5 ± 0.6 ^h	77.0 ± 0.1 ^h	3.7 ± 0.4^e	1.9 ± 0.2^e	15.5 ± 0.1^g
RN3	60.6 ± 0.9 ^h	82.5 ± 1.9 ^f	35.1 ± 0.3 ^k	3.3 ± 0.7^e	5.1 ± 0 ^de	19.5 ± 0.8 ^f
RN4	53.8 ± 1.5^i	58.3 ± 0.7 ^g	25.9 ± 0.2 ^l	1.9 ± 0.5^e	7.1 ± 0.2^d	18.7 ± 1.7 ^f
RP1	18.3 ± 3.6 ^j	36.5 ± 0.2 ^h	23.0 ± 0.2 ^l	2.3 ± 1.0^e	5.3 ± 0.1^de	12.8 ± 0.3 ^h
RP2	77.6 ± 1.7 ^g	94.7 ± 9.7 ^f	42.1 ± 0.4^i	5.8 ± 0^d	4.4 ± 0^de	19.0 ± 0.2 ^f
RP3	82.1 ± 0.6 ^g	98.0 ± 0.4 ^f	38.6 ± 0.2 ^j	3.0 ± 0^e	6.4 ± 0.1^d	19.3 ± 0.9 ^f

The names of peach and nectarine varieties are written in Table 1. Different letters in the column indicate significant differences at *P < 0.05.

Figure 2. Antioxidant capacity and polyphenol content of peaches and nectarines.

(a): DPPH radical scavenging activity; (b): Ferric reducing antioxidant power (FRAP); (c): ABTS radical scavenging activity; (d): Total polyphenol content (TPC); (e): Total flavonoid content (TFC). Different case letters indicate the significant difference (*P < .05). The names of peach and nectarine varieties are written in Table 1.

Table 3. Correlation coefficients between polyphenol, sugar, organic acid, amino acid levels and TPC, TFC and antioxidant capacity.

	TPC	TFC	DPPH	FRAP	ABTS
Neochlorogenic acid	0.925**	0.902**	0.969**	0.935**	0.906**
Catechin	0.795**	0.791**	0.917**	0.807**	0.801**
Chlorogenic acid	0.878**	0.854**	0.858**	0.883**	0.840**
Quercitrin	0.708**	0.761**	0.648*	0.656*	0.624*
Hyperoside	0.820**	0.742**	0.766**	0.816**	0.803**
Rutin	0.475	0.337	0.437	0.488	0.532
TPC	1	0.981**	0.944**	0.993**	0.960**
TFC	0.981**	1	0.912**	0.970**	0.932**
Sorbitol	−0.163	−0.149	−0.162	−0.126	−0.011
Glucose	0.464	0.402	0.411	0.485	0.542
Sucrose	−0.902**	−0.896**	−0.831**	−0.890**	−0.821**
Fructose	−0.149	−0.236	−0.148	−0.124	0.004
Total sugar	−.0874**	−0.880**	−0.808**	−0.857**	−0.768**
Malic acid	0.967**	0.919**	0.923**	0.961**	0.937**
Citric acid	−0.504	−0.562*	−0.454	−0.507	−0.446
Quinic acid	0.960**	0.937**	0.906**	0.942**	0.900**
Oxalic acid	0.971**	0.971**	0.921**	0.957**	0.897**
Total organic acid	0.930**	0.874**	0.889**	0.916**	0.895**
Aspartic acid	0.668**	0.675**	0.550*	0.627*	0.616*
Threonine	0.945**	0.941**	0.903**	0.926**	0.850**
Serine	0.938**	0.941**	0.882**	0.919**	0.843**
Glutamic acid	0.919**	0.925**	0.870**	0.911**	0.829**
Glycine	0.946**	0.938**	0.871**	0.930**	0.865**
Alanine	0.957**	0.956**	0.898**	0.938**	0.866**
Cystine	0.922**	0.933**	0.862**	0.902**	0.849**
Valine	0.911**	0.917**	0.853**	0.906**	0.822**
Methionine	0.926**	0.943**	0.863**	0.907**	0.820**
Isoleucine	0.945**	0.951**	0.878**	0.919**	0.855**
Leucine	0.886**	0.909**	0.771**	0.863**	0.770**
Tyrosine	0.943**	0.947**	0.887**	0.918**	0.846**
Phenylananine	0.925**	0.931**	0.870**	0.912**	0.835**
Lysine	0.959**	0.957**	0.902**	0.943**	0.868**
Histidine	0.372	0.285	0.27	0.347	0.288
Arginine	0.675**	0.649*	0.701**	0.644*	0.594*
Proline	−0.129	−0.137	−0.088	−0.142	−0.218
Total amino acid	0.909**	0.893**	0.812**	0.880**	0.811**

* represents significant correlation at the 0.05 level (*P < 0.05); ** represents significant correlation at the 0.01 level (**P < 0.01).

TPC, Total polyphenol content; TFC: total flavonoid content.

Figure 3. Heat map visualization of soluble sugar, organic acid and amino acid levels in 7 peach and nectarine varieties.

The content of each component was normalized to complete linkage hierarchical clustering. Sample is in column and component is in row, whereas the green represents undetected. The names of peach and nectarine varieties are written in Table 1.

Figure 4. Multivariate OPLS-DA and PCA of the physicochemical characteristics of thinned and ripe fruit of 7 Chinese peach and nectarine varieties.

(a): Scores plot of thinned and ripe fruit (OPLS-DA); (b): S-Plots of thinned and ripe fruit in a separate group (OPLS-DA); (c): Scores Plot of thinned peaches and nectarines (PCA); (d): Loadings plot of thinned peaches and nectarines (PCA); (e): Scores Plot of ripe peaches and nectarines (PCA); (f): Loadings plot of ripe peaches and nectarines (PCA).The names of peach and nectarine varieties are written in Table 1. The gray ellipses include 95% of the normal multivariate distribution of the peach (red) and nectarine (blue) samples. In the scores plot, the scores t [1] and t [2] are new variables summarizing the X–variables. In the loadings plot, p [1] vs p [2] displays the relation of the X–variables to each other.