Carotenoid Profiling in the Peel and Pulp of 36 Selected Musa Varieties

Zhou Heng; Ou Sheng; Shijuan Yan; Hongxian Lu; Ievgen Motorykin; Huijun Gao; Chunyu Li; Qiaosong Yang; Chunhua Hu; Ruibin Kuang; Fangcheng Bi; Tongxin Dou; Shenxi Xie; Guiming Deng; Ganjun Yi

doi:10.3136/fstr.23.603

Abstract

Bananas (Musa spp.) are not only one of the most popular fruits but also important staple food in some tropic countries. Carotenoid in pulp of banana fruits is an important source of vitamin A. While little is reported on carotenoid in peel, which is traditionally recognized as byproduct of food industry and may be a potential source of antioxidant compounds. Here we determined and reported carotenoid content and composition in both peel and pulp of 36 different banana cultivars. A total of 3 and 8 carotenoid components were identified in pulp and peel, respectively. The results show that carotenoid ranged from 0.18 to 36.82 µg/g FW in pulp and 0.9 to 16.2 µg/g FW in peel. Vitamin A values as retinol activity equivalents (RAE) in the pulp ranged from 0.003 to 1.85 µg/g. This report represents the first comprehensive assessment of carotenoid profiling in both fruit peel and pulp of 36 white to orange types of bananas and demonstrates banana peel product is also a valuable source with great nutritional properties.

Introduction

Bananas (Musa spp.) are herbaceous perennial plants represents a major source of carbohydrates in the diets of a large percentage of the world's population (Ortiz and Swennen 2014). Carotenoids in banana fruits, which serve as precursors of Vitamin A are vital for people who take banana as staple food with important nutritional properties (Englberger, Schierle et al. 2003, Englberger, Schierle et al. 2006, Davey, Van den Bergh et al. 2009, D'Hont, Denoeud et al. 2012, Ekesa, Poulaert et al. 2012, Ortiz and Swennen 2014, Buah 2015). Thus the development of genetically engineered banana cultivars with high carotenoid content has been a desired goal for scientists and breeders.

Some efforts have already been made to profile the carotenoid but mainly focus on the fruit pulp. For example, carotenoid content in pulp of plenty banana cultivar grown in Brazil, Solomon Islands, Thailand has been screened by spectrophotometer or High Performance Liquid Chromatography (HPLC) (Charoensiri, Kongkachuichai et al. 2009, Davey, Van den Bergh et al. 2009, Englberger, Lyons et al. 2010). However, more screen and analysis should be taken, particularly no systematical measurements of carotenoid profiling have been made yet in peel product of Musa species

As main byproducts of banana which represents about 35% of the total fresh mass of ripe fruit, banana peel is rich in dietary fiber, protein, essential amino acids, polyunsaturated fatty acids and potassium (Happi Emaga, Andrianaivo et al. 2007). It also contains antioxidant compounds including polyphenols, catecholamines and carotenoids (Rebello, Ramos et al. 2014) (González-Montelongo, Gloria Lobo et al. 2010). Consequently, it becomes necessary to make full use of these residues to avoid environmental problems as well as economic losses. To achieve this goal, more information about banana peel should be acquired. Ajay et al has reported the analysis of carotenoid in banana peel of 8 cultivars grown in India (Arora, Choudhary et al. 2008). However, the quantity of cultivar together with the accuracy of content and composition of carotenoids in banana peel were relatively limited. Thus a comprehensive assessment with more data precision from more cultivar is highly needed.

In order to get more information about carotenoid content and composition in both peel and pulp from many different banana cultivar, we conducted the study on 36 variable banana fruits (from white to orange types) as well as plenty banana germplasm grown in Guangzhou National Agriculture Science and Technology Park. The results and potential value of banana fruit peel as a new source of carotenoid were discussed.

Materials and Methods

Collection and preparation of samples Fruits from 36 accessions (Table 1) were sampled after full developed in Guangzhou National Agriculture Science and Technology Park, Guangzhou, Guangdong, China. Peel and pulp of fruits were separated, cut in small pieces and put in liquid nitrogen immediately, stored at −80°C for further use. Each sample consisted of three biological replicates. Chemicals were purchased from Sigma–Aldrich, St. Louis, USA

Table 1. Sample information and water content of 36 selected banana cultivars

Accession number	Accession name	Genotype	Subgroup	Water content %
Accession number	Accession name	Genotype	Subgroup	Pulp	Peel
GY0049	Pisang Berlin	AA		74.03±1.15	87.68±0.82
GY0047	Khai (Kampengpeth)	AA		78.00±1.29	87.03±0.10
GY0031	PisangJaran	AA		71.44±1.42	90.79±0.51
GY0042	PisangJariBuaya	AA		71.80±1.37	90.04±0.33
GY0030	TuuGia	AA		71.1±1.09	87.88±0.87
GY0058	NBA 14	AA		71.69±0.75	89.44±0.46
GY0016	Sepi	AA		78.78±1.38	91.06±1.58
	BGY3	BB		70.46±0.53	90.48±0.16
GY0060	Dwarf Cavendish	AAA	Cavendish	75.05±1.26	92.45±0.34
GY0008	Kazirakwe	AAA	Mutika/Lujugira	70.63±1.52	92.81±0.43
GY0035	Highgate	AAA	Gros Michel	75.12±0.11	91.37±0.48
GY0004	Ibwi	AAA		74.84±0.40	91.70±1.17
ITC1586	Grand Naine	AAA	Cavendish	74.30±0.81	92.43±0.92
	ZT	AAA	Cavendish	75.20±0.46	92.04±0.30
	WIH	AAA	red	71.20±0.45	91.93±0.34
GY0001	ObubitNtanga green mutant	AAB	Plantain	65.62±0.90	88.68±0.50
GY0007	Orishele	AAB	Plantain	64.96±1.25	88.12±1.65
GY0037	Prata	AAB	Pome	69.87±0.49	90.17±0.81
GY0034	TM3x 15108-6	AAB		70.24±0.87	88.37±0.48
GY0020	Dwarf French Plantain	AAB	Plantain	64.23±1.43	88.20±0.64
GY0043	Yangambi No. 2	AAB	silk	71.80±0.85	90.12±0.56
	F10428	ABB	PisangAwak	72.71±0.93	92.87±0.43
	X3	ABB	PisangAwak	75.22±0.75	92.07±0.39
GY0033	SH 3436-6	AAAA		78.05±1.13	92.90±0.59
GY0059	PC12-05	AAAB		67.32±0.67	90.57±0.96
GY0044	PV 42-53	AAAB		80.81±1.38	90.54±1.19
GY0045	PV 42-68	AAAB		76.64±0.83	89.61±1.07
GY0027	PV03-44	AAAB		73.26±0.15	92.77±0.85
GY0065	JV 42-41	AAAB		73.13±0.67	92.89±0.77
GY0039	PV 42-81	AAAB		74.08±0.95	90.12±0.22
GY0025	PA03-22	AAAB		79.79±0.95	90.86±0.73
GY0162	DF1			70.93±0.47	92.26±0.36
GY0163	DF2			72.05±0.87	93.23±0.41
GY0164	DF3			68.68±0.88	92.40±0.31
GY0165	DF4			71.95±0.75	91.83±0.33
GY0166	DF5			65.53±0.82	89.95±0.54

Determination of water content Water content were obtained by drying sample in an oven at 70°C until the weight was steady.

Carotenoid extraction A modified protocol based on the method reported by Davey was used (Davey, Keulemans et al. 2006). Frozen peel and pulp was grounded into a fine powder. Either 4 g of peel or 8 g of pulp powder was resuspended in 20 mL extraction solution (hexane/acetone/ethanol (2:1:1, v/v/v), containing 0.1% butylated hydroxytoluene (BHT)) and ultrasonic treated for 30 min. Samples were centrifuged for 15 min at 13,000×g, the supernatant was transferred to a new tube. The pellet was extracted twice more and the supernatants were combined. Merged supernatant was mixed with 30 mL 10% sodium chloride (NaCl). Upper phase was transferred into a new tube. Repeat this step for three times. Then upper phase were evaporated to dryness under vacuum (Eppendorf Concentrator plus™)

Saponification Dried pullet was resuspended in 2 mL methyl tert-butyl ether (MTBE), then 2 mL freshly-prepared 10% potassium hydroxide (KOH)–methanol was added, and the mixture was incubated at room temperature for 10 h. The incubated mixture was washed by 10% NaCl 3 times again, and evaporated to dryness under vacuum.

HPLC analysis of carotenoid Chromatographic analysis was performed using an Agilent 1260 Infinity Liquid Chromatograph System. The chromatography separation was carried out using a C30 HPLC column (250×4.6 mm I.D., 5 µm). The column was thermostatted at 20°C. Detection was carried out in the range 300 – 600 nm, at a frequency of 80 Hz. Chromatograms were generated at 450 nm. Gradient elution was performed at 1 mL/min under the following conditions: 0 – 10 min A : B : C (24:72:4) ; 10 – 19 min A : B : C (22:66:12) ; 19 – 29 min A : B : C (19:57:24); 29 – 54 min A : B : C (13:39:48) ; 54 – 66 min A : B : C (7:21:72) ; 66 – 67 min A : B : C (24:72:4) ; 67 – 78 min A : B : C (24:72:4). Solvent A consisted of 100%methanolwith 0.05% triethylamine (TEA) and 0.1% BHT. Solvent B consisted of 100% acetonitrile containing 0.05% triethylamine (TEA) and 0.1% BHT. Solvent C consisted of 100% MTBE with 0.1% BHT.

Identification of carotenoids was achieved by both the comparison of retention times, λmax and spectral structure at 450 mm relative to standard reagent (Table S1). Quantification of carotenoids was performed by comparison of HPLC absorbance peak areas with a standard curve constructed from the standard reagents (Table S2).

Table S1. Retention times and λmax of each catoenoid

Carotenoid	R_t^a (min)	λ_max^b
neoxanthn	12.4	412, 436 ,468
lutein	20.3	424, 450, 476
α-cryptoxanthn	28.3	424, 448, 476
β-cryptoxanthn	32.4	456, 480
α-carotene	36.7	424, 448, 476
β-carotene	40.7	458, 480
δ-carotene	49.6	432, 460, 492
γ-carotene	54.5	440, 464, 496
ζ-carotene	43.1	380, 400, 428
violaxanin	9.8	416, 440, 472
antherthin	16.1	424, 448, 476
zeaxanthin	24.3	452, 480
lycopene	66.6	448, 472, 504

a Retention time,

b Maximum absorption wavelength determined by standard sample

Table S2. Standard curve and determination coefficient of each carotenoid standard reagent

Carotenoid	Standard curve	R²
neoxanthin	y = 907.4x − 125.46	0.9997
lutein	y = 1830.6x	1
α-cryptoxanthin	y = 1600.6x − 50.163	1
β-cryptoxanthin	y = 1844.2x + 84.702	0.9999
α-carotene	y = 677.83x − 43.174	0.9999
β-carotene	y = 1858.5x + 270.91	0.9994
δ-carotene	y = 1942.6x + 746.98	0.9985
γ-carotene	y = 1326.7x − 134.44	1
ζ-carotene	y = 731.86x − 81.907	1
violaxanthin	y = 1304.6x + 139.25	0.9998
antheraxanthin	y = 1277.2x + 337.36	0.9987
zeaxanthin	y = 1740.7x + 23.703	1
lycopene	y = 1059.2x − 25.073	1

Determination of the retinol activity equivalent A measure of retinol activity equivalent (RAE) based on the capacity of the body to convert provitamin carotenoids to retinaldehyde is 1 mg RAE=1 mg retinol = 12 mg β-carotene = 24 mg other vitamin A precursor carotenoids (Institute of Medicine, Food and Nutrition Board, 2000: 325–400).

Statistical analysis Data were subjected to one way ANOVA followed by post hoc LSD test using SPSS 19 (SPSS Inc. Chicago, IL, USA) for determining significant differences. Difference was considered significant when p < 0.05.

Results and Discussion

Carotenoid content and composition of banana pulp The carotenoids of fruit pulp from 36 cultivars were measured. A wide variation of total carotenoid contents was found in the pulp of 36 banana cultivars, ranging from 0.18 µg/g FW in white fleshed ‘Yangambi No.2’ to.36.82 µg/g FW in orange fleshed ‘Orishele’(Table 2). ‘Orishele’ have been used as experiment control in many researches about properties of new hybrid plantain cultivar (Coulibaly, Nemlin et al. 2006, Tetchi, Coulibaly et al. 2012) Retinol activity equivalents (RAE) in fruit pulp were calculated and showed in Table 2. RAE ranged from 0.003 to 1.85 µg/g FW. Some high RAE cultivars were excellent source of vitamin A. Moreover, some cultivars were good material for carotenoid metabolism research in banana.

Table 2. Caroteniod Composition and Content in Banana pulp^a

Accession name	Lutein (%)	α-carotene (%)	β-carotene (%)	total carotenoids	RAE
Orishele	0.6±0.11 (1.63)	27.22±0.86 (73.91)	8.53±0.2 (23.18)	36.82±1.09a	1.85
Dwarf French Plantain	0.7±0.09 (6.03)	7.81±1.48 (67.33)	2.85±0.48 (24.57)	11.65±2.07b	0.56
ObubitNtanga green mutant	0.29±0.02 (3.39)	6.12±1.38 (71.58)	2.05±0.46 (23.98)	8.55±1.86c	0.43
NBA 14	0.58±0.12 (7.5)	5.32±0.98 (68.82)	1.64±0.34 (21.22)	7.73±1.47c	0.36
PA03-22	0.58±0.1 (9.48)	4.51±0.44 (73.69)	0.89±0.04 (14.54)	6.12±0.57d	0.26
Pisang Berlin	0.54±0.03 (9.89)	3.29±0.29 (60.26)	1.58±0.12 (28.94)	5.46±0.37de	0.27
Sepi	0.2±0.03 (3.84)	4.35±0.33 (83.49)	0.63±0.07 (12.09)	5.21±0.44de	0.23
DF2	1.48±0.03 (30.9)	2.12±0.17 (44.26)	0.51±0.05 (10.65)	4.79±0.35e	0.13
PisangJaran	0.11±0.03 (2.43)	3.12±0.53 (69.03)	1.24±0.21 (27.43)	4.52±0.77e	0.23
Khai (Kampengpeth)	0.72±0.07 (20.99)	1.95±0.06 (56.85)	0.71±0.02 (20.7)	3.43±0.12f	0.14
PisangJariBuaya	0.4±0.08 (12.99)	2.22±0.3 (72.08)	0.43±0.06 (13.96)	3.08±0.43f	0.13
DF4	1.14±0.19 (38.78)	0.92±0.16 (31.29)	0.45±0.07 (15.31)	2.94±0.43f	0.08
Kazirakwe	0.15±0.03 (5.51)	2.25±0.31 (82.72)	0.31±0.04 (11.4)	2.72±0.29f	0.12
PV 42-81	0.1±0 (4.08)	1.66±0.41 (67.76)	0.69±0.23 (28.16)	2.45±0.63fg	0.13
BGY3	0.07±0.01 (4.55)	0.08±0.01 (5.19)	0.36±0.03 (23.38)	1.54±0.07gh	0.03
WIH	0.32±0.15 (22.54)	0.93±0.15 (65.49)	0.16±0.03 (11.27)	1.42±0.29hi	0.05
TM3x 15108-6	0.39±0.04 (29.1)	0.8±0.14 (59.7)	0.13±0.02 (9.7)	1.34±0.2hij	0.04
F10428	0.24±0.05 (21.43)	0.62±0.05 (55.36)	0.25±0.01 (22.32)	1.12±0.11hijk	0.05
JV 42-41	0.27±0.02 (27.27)	0.64±0.03 (64.65)	0.06±0.01 (6.06)	0.99±0.06hijk	0.03
PC12-05	0.31±0.05 (33.33)	0.48±0.22 (51.61)	0.13±0.02 (13.98)	0.93±0.28hijk	0.03
SH 3436-6	0.27±0.03 (34.18)	0.45±0.07 (56.96)	0.06±0.01 (7.59)	0.79±0.11hijk	0.02
PV 42-68	0.42±0.06 (55.26)	0.27±0.09 (35.53)	0.05±0.02 (6.58)	0.76±0.14hijk	0.02
Grand Naine	0.03±0 (4.55)	0.51±0.05 (77.27)	0.12±0.01 (18.18)	0.66±0.06hijk	0.03
X3	0.08±0.02 (12.7)	0.38±0.04 (60.32)	0.16±0.02 (25.4)	0.63±0.08hijk	0.03
PV 42-53	0.17±0.01 (27.87)	0.34±0.12 (55.74)	0.07±0.01 (11.48)	0.61±0.12hijk	0.02
TuuGia	0.17±0.02 (32.69)	0.27±0.02 (51.92)	0.08±0.01 (15.38)	0.52±0.05ijk	0.02
PV03-44	0.35±0.03 (70)	0.11±0.02 (22)	0.02±0 (4)	0.5±0.03ijk	0.01
DF5	0.29±0.03 (59.18)	0.1±0.01 (20.41)	0.06±0.01 (12.24)	0.49±0.05ijk	0.01
DF1	0.12±0.01 (26.67)	0.25±0.03 (55.56)	0.04±0.01 (8.89)	0.45±0.05ijk	0.01
DF3	0.28±0.06 (63.64)	0.14±0.03 (31.82)	0.02±0 (4.55)	0.44±0.09ijk	0.01
Prata	0.12±0 (29.27)	0.23±0.03 (56.1)	0.06±0.01 (14.63)	0.41±0.04jk	<0.01
ZT	0.11±0.03 (28.21)	0.25±0.03 (64.1)	0.03±0.01 (7.69)	0.39±0.07jk	<0.01
Highgate	0.13±0.02 (38.24)	0.16±0.04 (47.06)	0.02±0.01 (5.88)	0.34±0.07k	<0.01
Dwarf Cavendish	0.11±0.03 (34.38)	0.17±0.04 (53.13)	0.03±0 (9.38)	0.32±0.07k	<0.01
Ibwi	0.15±0.03 (50)	0.09±0.02 (30)	0.06±0.01 (20)	0.3±0.06k	<0.01
Yangambi No. 2	0.09±0.02 (50)	0.03±0.02 (16.67)	0.02±0 (11.11)	0.18±0.02k	<0.01
Mean	0.33 (25±06)	2.18 (54.75)	0.67 (15.23)	3.28	0.15
STD	0.3 (18.86)	4.64 (19.07)	1.48 (7.20)	6.28	0.32

a Value in mean ± STD (n=3) in µg/g FW. Total carotenoid content followed by the same letter in the columns belong to the same group by the LSD test at 5% probability.

Quartile deviation was used to divide the amount of total carotenoid in fruit pulp into three levels which were high (higher than 3.975 µg/g FW), medium (from 3.9755 to 0.495 µg/g FW) and low (lower than 0.495 µg/g FW). High total carotenoid content was found in ‘Orishele’ ‘Dwarf French Plantain’ ‘Obubit Ntanga green mutant’ ‘NBA 14’ ‘PA03-22’ ‘Pisang Berlin’ ‘Sepi’ ‘DF2’ ‘PisangJaran’. Interestingly, top 3 of total content were in Plantain subgroup. Varieties with medium carotenoids content were Khai (Kampengpeth),PisangJariBuaya, DF4, Kazirakwe, PV 42-81, BGY3, WIH, TM3x 15108-6, F10428, JV 42-41, PC12-05, SH 3436-6, PV 42-68, SH-3764, Grand Naine, X3, PV 42-53, TuuGia, PV03-44. Those with low carotenoid content were DF5, DF1, DF3, Prata, ZT, Highgate, Dwarf Cavendish, Ibwi, Yangambi No.2.

At subgroup level, Plantain has the highest carotenoid content for ranking top 3 of total carotenoid content in this work. Cultivar in Cavendish subgroup had low carotenoid content. This confirmed findings in other research about banana carotenoid (Davey, Van den Bergh et al. 2009) . Difference of carotenoid content among cultivars in the same subgroup was smaller than cultivars in the same genome group. To better understand the relation between carotenoid content and subgroup classification of banana, more data and research about carotenoid metabolism are needed.

Three carotenoids identified in pulp were lutein, α-carotene and β-carotene. As show in table 2, percentage of them in total carotenoid from each cultivar ranged from 1.63 to 70%, 5.19 to 83% and 4 to 28.94%, respectively. Average percentage of these three compounds from 36 cultivars was about 25%, 55% and 15%. Cultivars in this work are mainly accumulated α-carotene and lutein which are at α branch in the carotenoid biosynthesis pathway. This was demonstrated in other research works (Davey, Van den Bergh et al. 2009, Englberger, Lyons et al. 2010). The branched step which represented one of the key steps in carotenoid biosynthesis was regulated by lycopene β-cyclase (LCYB) and lycopene ε-cyclase (LCYE)(Nisar, Li et al. 2015). Buah has cloned LCYB gene in banana fruits (Buah 2015), however, the reason why banana fruits accumulate more α-carotene is still unknow.

Carotenoid content and composition of banana peel Range of total carotenoid content in peel was from 0.9 to16.2 µg/g FW (Table 3). Cultivar had the highest total carotenoid content in peel was ‘Orishele’ and the lowest was ‘DF2’. Different from the previous study (Arora, Choudhary et al. 2008), in this work, it is not in all cultivar that peel has more carotenoid content than pulp. For example, ‘Obubit Ntanga green mutant’ ‘Orishele’ ‘Dwarf French Plantain’ have more carotenoid in pulp than in peel. Total carotenoid content of banana peel has a narrow range than banana pulp which is indicate that there are different carotenoid metabolite mechanisms between banana peel and pulp. There is only a few research about carotenoid biosynthesis in banana pulp (Buah 2015), and no research about carotenoid biosynthesis in banana peel. Data in this paper support physiology information for future research. Eight carotenoids were identified from peel of 36 cultivars. As show in table 3, average percentage of lutein in total carotenoids from 36 cultivars was 40.32, followed by α-carotene (28.51%) and β-carotene (14.14%). violaxanthin (2.13%), neoxanthin (4.15%), antheraxanthin (7.79%), α-cryptoxanthin (1.78%) and β-cryptoxanthin (1.28%) were detectable, but in a relatively low content when compare with the three major carotenoids. Sum of average proportion of these five carotenoids is only 17.14%. Consequently, major component of carotenoid in banana pulp and peel are lutein, α-carotene and β-carotene.

Table 3. Caroteniod Composition and Content in Banana peel^a

Accession name	Violaxanthin (%)	Neoxanthin (%)	Antheraxanthin (%)	Lutein (%)	α-Cryptoxanthin (%)	β-Cryptoxanthin (%)	α-carotene (%)	β-carotene (%)	Total carotenoids
Orishele	0.08±0.01 (0.49)	0.19±0.02 (1.17)	0.23±0.05 (1.42)	2.15±0.3 (13.27)	0.1±0.01 (0.62)	0.17±0.03 (1.05)	10.54±1.85 (64.81)	2.74±0.27 (16.91)	16.2±2.48a
Dwarf French Plantain	0.11±0.02 (1.1)	0.25±0.01 (2.5)	0.27±0.02 (2.7)	2.51±0.15 (25.1)	0.49±0.04 (4.9)		4.86±0.44 (48.6)	1.55±0.14 (15.5)	10.04±0.76cd
ObubitNtanga green mutant	0.08±0.02 (1.35)	0.14±0.02 (2.36)	0.61±0.05 (10.29)	1.59±0.19 (26.81)	0.06±0.01 (1.01)	0.11±0.01 (1.85)	2.36±0.26 (39.8)	0.97±0.18 (16.36)	5.93±0.65ij
NBA 14	0.08±0.01 (1.22)	0.33±0.03 (5.02)	0.86±0.13 (13.09)	3.43±0.73 (52.21)	0.17±0.02 (2.59)	0.11±0.09 (1.67)	1.15±0.89 (17.5)	0.44±0.35 (6.7)	6.57±1.21hi
PA03-22	0.51±0.03 (5.34)	0.11±0 (1.15)	0.75±0.04 (7.85)	2.65±0.15 (27.75)	0.24±0.02 (2.51)	0.1±0.01 (1.05)	3.9±0.33 (40.84)	1.3±0.12 (13.61)	9.55±0.68cde
Pisang Berlin	0.07±0.02 (0.91)	0.21±0.02 (2.73)	0.25±0.05 (3.25)	3.37±0.39 (43.77)	0.18±0.02 (2.34)	0.12±0.02 (1.56)	2.16±0.16 (28.05)	1.35±0.1 (17.53)	7.7±0.75gh
Sepi	0.21±0.09 (2.51)	0.38±0.06 (4.55)	0.44±0.09 (5.26)	2.11±0.36 (25.24)	0.12±0.02 (1.44)		3.97±0.77 (47.49)	1.14±0.22 (13.64)	8.36±1.57efg
DF2	0.04±0.01 (4.44)	0.05±0 (5.56)	0.05±0.01 (5.56)	0.24±0.02 (26.67)			0.36±0.04 (40)	0.17±0.02 (18.89)	0.9±0.06q
PisangJaran	0.17±0.04 (4.63)	0.19±0.07 (5.18)	0.22±0.04 (5.99)	1.38±0.28 (37.6)	0.05±0.01 (1.36)	0.03±0.01 (0.82)	1.16±0.08 (31.61)	0.47±0.07 (12.81)	3.67±0.31mno
Khai (Kampengpeth)	0.09±0.01 (1.15)	0.26±0.08 (3.31)	0.37±0.07 (4.71)	2.93±0.33 (37.32)	0.13±0.03 (1.66)	0.2±0.04 (2.55)	2.54±0.49 (32.36)	1.32±0.21 (16.82)	7.85±1.11fgh
PisangJariBuaya	0.04±0.01 (1.34)	0.11±0.01 (3.68)	0.13±0.04 (4.35)	1.11±0.06 (37.12)	0.06±0.01 (2.01)	0.05±0.01 (1.67)	0.99±0.01 (33.11)	0.49±0 (16.39)	2.99±0.04nop
DF4	0.09±0.02 (0.9)	0.82±0.04 (8.2)	0.98±0.09 (9.8)	3.6±0.09 (36)	0.12±0.01 (1.2)	0.05±0.01 (0.5)	2.98±0.44 (29.8)	1.45±0.23 (14.5)	10.09±1.18c
Kazirakwe	0.15±0.03 (1.75)	0.18±0.03 (2.1)	0.46±0.07 (5.36)	3.74±0.38 (43.54)	0.19±0.01 (2.21)	0.1±0.01 (1.16)	2.61±0.17 (30.38)	1.18±0.07 (13.74)	8.59±0.41defg
PV 42-81	0.11±0.01 (3.61)	0.19±0.03 (6.23)	0.28±0.04 (9.18)	1.06±0.21 (34.75)	0.03±0.01 (0.98)	0.09±0.01 (2.95)	0.66±0.17 (21.64)	0.63±0.07 (20.66)	3.05±0.48nop
BGY3	0.15±0.02 (1.74)	0.21±0.02 (2.44)	0.64±0.06 (7.42)	2.52±0.23 (29.23)		0.04±0.01 (0.46)	2.72±0.27 (31.55)	2.35±0.25 (27.26)	8.62±0.77cdefg
WIH	0.09±0.02 (0.98)	0.42±0.13 (4.57)	1.04±0.18 (11.32)	4.39±0.92 (47.77)	0.18±0.04 (1.96)	0.19±0.04 (2.07)	2.02±0.46 (21.98)	0.85±0.2 (9.25)	9.19±1.97cdef
TM3x 15108-6	0.07±0.01 (1.67)	0.23±0.03 (5.48)	0.28±0.05 (6.67)	1.6±0.62 (38.1)	0.11±0.01 (2.62)	0.03±0.01 (0.71)	1.35±0.11 (32.14)	0.51±0.05 (12.14)	4.2±0.85klmn
F10428	0.12±0.02 (4.46)	0.09±0.01 (3.35)	0.43±0.03 (15.99)	0.67±0.08 (24.91)	0.02±0.01 (0.74)	0.08±0.01 (2.97)	0.51±0.04 (18.96)	0.76±0.06 (28.25)	2.69±0.25op
JV 42-41	0.15±0.03 (1.9)	0.33±0.11 (4.19)	0.59±0.2 (7.49)	4.12±0.64 (52.28)	0.2±0.01 (2.54)	0.09±0.01 (1.14)	1.72±0.34 (21.83)	0.67±0.03 (8.5)	7.88±0.73fgh
PC12-05	0.04±0 (0.72)	0.14±0.01 (2.51)	0.67±0.12 (12.03)	3.02±0.29 (54.22)	0.06±0.01 (1.08)	0.05±0.01 (0.9)	0.97±0.06 (17.41)	0.6±0.04 (10.77)	5.57±0.52ijk
SH 3436-6	0.07±0.01 (2.1)	0.17±0.03 (5.11)	0.39±0.05 (11.71)	1.58±0.16 (47.45)	0.08±0.01 (2.4)	0.05±0.01 (1.5)	0.65±0.05 (19.52)	0.34±0.03 (10.21)	3.33±0.31no
PV 42-68	0.11±0.02 (2.7)	0.17±0.04 (4.17)	0.32±0.03 (7.84)	2.01±0.13 (49.26)	0.07±0.01 (1.72)	0.06±0.01 (1.47)	0.75±0.21 (18.38)	0.59±0.15 (14.46)	4.08±0.48lmno
Grand Naine	0.09±0.02 (1.1)	0.21±0.06 (2.56)	0.59±0.06 (7.19)	2.69±0.61 (32.76)	0.25±0.05 (3.05)	0.07±0.01 (0.85)	3.08±0.66 (37.52)	1.23±0.28 (14.98)	8.21±1.68efg
X3	0.02±0 (1.26)	0.04±0 (2.52)	0.19±0.04 (11.95)	0.41±0.09 (25.79)	0.01±0.01 (0.63)	0.05±0.01 (3.14)	0.38±0.09 (23.9)	0.5±0.04 (31.45)	1.59±0.26pq
PV 42-53	0.08±0.02 (2.17)	0.11±0.01 (2.98)	0.26±0.03 (7.05)	1.51±0.27 (40.92)	0.07±0.02 (1.9)	0.05±0.01 (1.36)	0.99±0.18 (26.83)	0.62±0.07 (16.8)	3.69±0.47mno
TuuGia	0.04±0.01 (1.23)	0.16±0.01 (4.94)	0.04±0 (1.23)	1.78±0.15 (54.94)	0.02±0.01 (0.62)	0.01±0.01 (0.31)	0.83±0.05 (25.62)	0.37±0.02 (11.42)	3.24±0.19no
PV03-44	0.06±0.01 (1.46)	0.2±0.04 (4.88)	0.32±0.1 (7.8)	2.55±0.88 (62.2)	0.04±0.01 (0.98)	0.03±0.01 (0.73)	0.57±0.1 (13.9)	0.34±0.06 (8.29)	4.1±0.82klmno
DF5	0.23±0.02 (1.85)	0.89±0.03 (7.18)	1.26±0.13 (10.16)	5.87±0.81 (47.34)	0.14±0.02 (1.13)	0.12±0.02 (0.97)	2.83±0.43 (22.82)	1.15±0.2 (9.27)	12.49±1.62b
DF1	0.24±0.08 (4.05)	0.3±0.05 (5.07)	0.35±0.04 (5.91)	2.29±0.16 (38.68)	0.33±0.01 (5.57)	0.05±0.02 (0.84)	1.75±0.15 (29.56)	0.61±0.1 (10.3)	5.92±0.28ij
DF3	0.2±0.02 (3.31)	0.27±0.02 (4.47)	0.59±0.06 (9.77)	2.46±0.12 (40.73)	0.14±0.01 (2.32)	0.07±0 (1.16)	1.76±0.09 (29.14)	0.56±0.03 (9.27)	6.04±0.2ij
Prata	0.09±0.01 (1.78)	0.2±0.05 (3.96)	0.46±0.05 (9.11)	2.21±0.08 (43.76)	0.06±0.02 (1.19)	0.1±0.01 (1.98)	1.19±0.24 (23.56)	0.72±0.14 (14.26)	5.05±0.32jklm
ZT	(0)	0.11±0.01 (2.05)	0.69±0.15 (12.85)	2.55±0.25 (47.49)	0.13±0.01 (2.42)	0.05±0.01 (0.93)	1.37±0.08 (25.51)	0.47±0.03 (8.75)	5.37±0.46ijkl
Highgate	0.13±0.03 (2.1)	0.33±0.1 (5.34)	0.8±0.12 (12.94)	3.27±0.3 (52.91)	0.18±0.01 (2.91)	0.11±0.01 (1.78)	0.83±0.06 (13.43)	0.52±0.04 (8.41)	6.18±0.62ij
Dwarf Cavendish	0.14±0 (2.62)	0.16±0.05 (3)	0.46±0.04 (8.61)	3.17±0.38 (59.36)	0.16±0.03 (3)	0.05±0.02 (0.94)	0.82±0.29 (15.36)	0.37±0.11 (6.93)	5.34±0.81ijkl
Ibwi	0.06±0.02 (1.45)	0.33±0.07 (7.97)	0.28±0.05 (6.76)	1.79±0.15 (43.24)	0.02±0.01 (0.48)	0.04±0.01 (0.97)	1.13±0.1 (27.29)	0.49±0.04 (11.84)	4.14±0.35klmno
Yangambi No. 2	0.06±0.01 (5.13)	0.07±0.01 (5.98)	0.08±0.02 (6.84)	0.59±0.12 (50.43)	0.02±0.0 (11.71)	0.03±0.01 (2.56)	0.22±0.04 (18.8)	0.12±0.02 (10.26)	1.17±0.19q
Mean	0.12 (2.13)	0.24 (4.15)	0.45 (7.79)	2.33 (40.32)	0.12 (1.78)	0.08 (1.28)	1.88 (28.51)	0.82 (14.14)	6.02
STD	0.09 (1.36)	0.18 (1.74)	0.29 (3.58)	1.19 (11.25)	0.1 (1.21)	0.05 (0.82)	1.84 (10.72)	0.56 (5.7)	3.25

a Value in mean ± STD (n=3) in µg/g FW. Total carotenoid content followed by the same letter in the columns belong to the same group by the LSD test at 5% probability.

Global banana production is about 145 million tons. As peel represents about 35% of the total fresh mass of banana fruit, there is 50 million tons of banana peel need to be fully used. Banana peel could be used as biomass for bionethanation, substrate for banana oil extraction and eco-friendly filter for waste water treatment (González-Montelongo, Gloria Lobo et al. 2010, Lee, Yeom et al. 2010, Shar, Fletcher et al. 2016). It is also a profitable source of bioactive phenolic compounds (Rebello, Ramos et al. 2014). From data of this work, banana peel could also be a potential source of carotenoids. (Arora, Choudhary et al. 2008)

Principal Component Analysis To graph the relationship of carotenoid profile among different banana cultivars, Principal Component Analysis (PCA) was used. The dispersion of varieties according to PCA of pulp carotenoid profile was shown in Figure 1. Factor 1 (71.06%) and Factor 2 (28.54%) explained 99.60% of the variance of HPLC data. Cultivars with high α-carotene content were located in Factor 1 (+) while Factor 2 (+) contained those with high lutein content. Therefore, α-carotene and lutein showed the highest factorial contribution to Factor 1 and Factor 2 respectively.

Fig. 1.

Scatter plot of the PCA analysis of the total carotenoid content in banana pulp. Cultivars out of plot range were showed as: Accession name (X-axis, Y-axis)

Impact of genome group on carotenoid content in banana pulp has been discussed by Davey (Davey, Van den Bergh et al. 2009). According to his result, cultivars in AAB genome group have higher carotenoid content than cultivars in AA and AAA. Our data also show these trends. But that is only a broad indication and should be interpreted with caution. Overall, ANOVA and PCA analysis reveal that there are no clear divisions between the genome or subgroup classes.

PCA result of carotenoid profile in banana peel was shown in Figure 2. Factor 1 (45.08%) and Factor 2 (18.96%) explained 64.04% of the variance of HPLC data. Different from PCA results of banana pulp, cultivars with high lutein content were found in Factor 1 (+) and Factor 2 (+) contained those with high α-carotene content.

Fig. 2.

Scatter plot of the PCA analysis of the total carotenoid content in banana peel. Cultivars out of plot range were showed as: Accession name (X-axis, Y-axis)

These results reveal different carotenoid profile between banana pulp and peel and indicate different carotenoid metabolic regulation of them. Based on Buah's research, carotenoid metabolism in banana pulp is regulated by expression of carotenogenic genes (Buah 2015). However, there is no research about carotenoid metabolism of banana peel. According to data we already got for another unpublished research, there is significant difference on the expression level of genes in carotenoid metabolism pathway between banana peel and pulp. This may cause different carotenoid profile between banana peel and pulp. Furthermore there is a great quantity of chloroplasts in peel but not in pulp maybe another cause of different carotenoid profile.

Conclusions

In this work, proportion of carotenoid content and composition in peel and pulp of banana fruit were analyzed. Cultivar ‘Orishele’ has a considerable carotenoid content and functional properties (Coulibaly, Nemlin et al. 2006, Tetchi, Coulibaly et al. 2012) and could be an excellent material for banana biofortification. The other high RAE cultivars were also excellent source of vitamin A. Carotenoid content in banana pulp had a wider range than in peel. Despite all the other attempts people made for banana peel utilize, this work provide a systematic survey of carotenoid content and composition in banana peel and support physiology information for future research.

Acknowledgments The authors gratefully acknowledge the financial support of national science foundation of China (NSFC: No.31101510,31401850), Science and Technology Plan Project of Guangdong Province (No.2015A050502037, 2015A030302045, 2015A030302046), Musa germplasm resources protection (No.16RZZY-13) and 948 Project from Ministry of Agriculture of China (No. 2016-X22).

References

Arora, A., Choudhary, D. Agarwal, G. and Singh, V. P. (2008). Compositional variation in β-carotene content, carbohydrate and antioxidant enzymes in selected banana cultivars. Int. J. Food Sci. Technol. 43, 1913-1921.
Buah, S. (2015). Regulation of carotenoid biosynthesis in banana fruit. Doctor of Philosophy, Thesis. Queensland University of Technology.
Charoensiri, R., Kongkachuichai, R. Suknicom, S. and Sungpua P. (2009). Beta-carotene, lycopene, and alpha-tocopherol contents of selected Thai fruits. Food Chem, 113, 202-207.
Coulibaly, S., Nemlin, J. G. and Amani, G. N. G. (2006). Isolation and Partial Characterisation of Native Starches of new Banana and Plantain Hybrids (Musa spp.) in Comparison with that of Plantain Variety Orishele. Starch, 58, 360-370.
D'Hont, A., Denoeud, F. J M.. et al (2012). The banana (Musa acuminata) genome and the evolution of monocotyledonous plants. Nature, 488, 213-217.
Davey, M. W., Keulemans, J., and Swenne R. (2006). Methods for the efficient quantification of fruit provitamin A contents. J. Chromatogr. A 1136, 176-184.
Davey, M. W., Van den Bergh, I., Markham, R. Swennen, R. and Keuleman J. (2009). Genetic variability in Musa fruit provitamin A carotenoids, lutein and mineral micronutrient contents. Food Chem, 115, 806-813.
Ekesa, B., Poulaert M., Davey M. W., Kimiywe, J., d. Bergh I. V., Blomme G., and Dhuique-Maye C. (2012). Bioaccessibility of provitamin A carotenoids in bananas (Musa spp.) and derived dishes in African countries. Food Chem, 133, 1471-1477.
Englberger, L., Lyons G., Foley W., Daniells J., Aalbersberg B., Dolodolotawake U., Watoto C., Iramu E., Taki B., Wehi F., Warito P., and Taylo M. (2010). Carotenoid and riboflavin content of banana cultivars from Makira, Solomon Islands. J. Food Composi. Anal, 23, 624-632.
Englberger, L., Schierle J., Aalbersberg W., Hofmann P., Humphries J., Huang A., Lorens A., Levendusky A., Daniells J., Marks G. C., and Fitzgeral M. H. (2006). Carotenoid and vitamin content of Karat and other Micronesian banana cultivars. Int. J. food sci. nutri., 57, 399-418.
Englberger, L., Schierle J., Marks G. C., and Fitzgeral M. H. (2003). Micronesian banana, taro, and other foods: newly recognized sources of provitamin A and other carotenoids. J. Food Composi. Anal., 16, 3-19.
González-Montelongo, R., Gloria Lobo M., and González M. (2010). Antioxidant activity in banana peel extracts: Testing extraction conditions and related bioactive compounds. Food Chem, 119, 1030-1039.
Happi Emaga, T., Andrianaivo R. H., Wathelet B., Tchango J. T., and Paquot M. (2007). Effects of the stage of maturation and varieties on the chemical composition of banana and plantain peels. Food Chem, 103, 590-600.
Lee, E.-H., Yeom H.-J., Ha M.-S., and Ba D.-H. (2010). Development of banana peel jelly and its antioxidant and textural properties. Food Sci. Biotechnol., 19, 449-455.
Nisar, N., Li L., Lu S., Khin N. C., and Pogso B. J. (2015). Carotenoid metabolism in plants. Mol. plant, 8, 68-82.
Ortiz, R. and Swenne R. (2014). From crossbreeding to biotechnology-facilitated improvement of banana and plantain. Biotechnol. Adv., 32, 158-169.
Rebello, L. P. G., Ramos A. M., Pertuzatti P. B., Barcia M. T., Castillo-Muñoz N., and Hermosín-Gutiérre I (2014). Flour of banana (Musa AAA) peel as a source of antioxidant phenolic compounds. Food Res. Int., 55, 397-403.
Shar, Z. H., Fletcher M. T., Sumbal G. A., Sherazi S. T., Giles C., Bhanger M. I., and Nizaman S. M. (2016). Banana peel: an effective biosorbent for aflatoxins. Food Addit. Contam., Part A, 33, 849-860.
Tetchi, A. F., Coulibaly S., Adou M., and Aman G. N. (2012). Comparative characterization of some functional properties of flours of new plantain hybrids with the Orishele variety (Musa spp.) as control. Emir. J. Food Agric., 25, 1-9.

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