Tree Age and Harvesting Season Affected Physico-chemical and Bioactive Compounds of Elite Type of Gunda Gundo Orange (Citrus Spp) in the Northern Ethiopia

Figures & data

Table 1. Physio-chemical fruit quality of orange as affected by tree age and harvesting season

2017
Tree age	Fruit mass (g)		Seed no.		Seed mas (%)		Firmness		Acidity (%)		pH
							(kg cm^−2)
	OH	DH	OH	DH	OH	DH	OH	DH	OH	DH	OH	DH
Young	217.71^a	194.20 ^c	9.40^d	11.50 ^c	1.94^d	2.16 ^c	6.47^a	4.41^d	0.86^b	1.01b	3.73^a	3.55^bc
Moderate	209.69^b	202.60^b	9.21^d	13.60^ab	2.18 ^c	2.52^b	6.83^a	5.41 ^c	0.99^b	0.89^b	3.52^bc	3.65^ab
Old	189.02 ^c	176.31^d	15.01^a	9.42^d	3.37^a	2.07 ^c	6.87^a	6.70^ab	1.21^a	0.97^b	3.67^ab	3.39 ^c
2018
Young	188.85^a	194.86^a	16.80^a	11.70 ^c	5.85^a	4.12^d	5.71^ab	4.49 ^c	0.81 ^c	0.96^abc	3.69^a	3.61^ab
Moderate	164.7^bc	200.76^a	18.20^a	13.60^bc	4.90^bc	5.01^b	5.51^bc	5.36^bc	1,01^ab	0.89^bc	3.42 ^c	3.54^bc
Old	144.40 ^c	167.57^b	14.70^b	11.31 ^c	4.24 ^cd	4.10^d	6.63^a	5.90^ab	1.10^a	1.01^a	3.46 ^c	3.49^bc

Different letters in each column or row within each parameter indicate significant differences between means (P < 0.05). OH = October harvest, DH = December harvest

Figure 1. Interaction effect of tree age and harvest season on fruit rag, TSS and peel thickness (a-c 2017), (d-f 2018), A = young B = moderate, C = older trees, HS = harvesting season, O = October, D = December

Figure 2. Tree age (A-C) and harvest season (HS) in October (O) and December (D) interaction effect on juice content and fruit mass (2017a, 2018b), TSS and maturity index (2017 c, 2018d, A = young, B = moderate, C = old tree ages

Figure 3. Tree age effect on sugar content (%), values are average of triplicate measurements (mean ± SD), A = young, B = moderate, C = old tree ages

Table 2. DPPH activity EC₅₀, total phenolic and Vitamin C contents of orange affected by tree age

Tree age	DPPH scavenging activity EC50 (mg mL^−1)	Total phenolic (mgGAE g^−1)	Vitamin C (mg 100 g ^−1)
Young	2.28^a	8.25^b	53.95^a
Moderate	1.99^ab	7.72^b	40.07 ^c
Old	1.50^b	9.15^a	50.64^b
Ascorbic acid*	0.064 ^c*

The same letters within each column indicate no significant differences between means (P < 0.05)

*L- ascorbic acid as standard check

Figure 4. DPPH radical scavenging activity (a), Ferric reducing power (mg of ascorbic acid per gram of juice) (b) and total antioxidant capacity of orange juice at different concentrations using phosphomolybdenum method butylated hydroxytoluene equivalent (mg BHTE g⁻¹), (c) from different tree ages (GA1 = young, GA2 = moderate and GA3 = old, trees age). Values are average of triplicate measurements (mean ±SD)

Table 3. Correlations between antioxidant activities assays on total phenolic and vitamin C content

Antioxidant activities assay	Total phenolic	Vitamin C
DPPH scavenging	0.73**	0.79**
Ferric ion reducing power	0.88*	0.72*
Total antioxidant capacity	0.84*	0.85*

* indicates significance at p < 0.05, ** indicates significance at p < 0.01