Post-harvest quality evaluation of physico-chemical and chemical characteristics in umbu fruit at different storage conditions
Evaluación de la calidad postcosecha de las características físico-químicas y químicas en el fruto de umbu a diferentes condiciones de almacenmiento

Abstract

Umbu (Spondias tuberosa Arruda Câmara) fruit was analyzed for its physical, physico-chemical, and chemical characteristics at two stages of its physiological maturity (half-ripe and ripe). Half-ripe fruit was stored at different conditions: (1) ambient (27 ± 2 °C and 60–75% relative humidity) and (2) at refrigeration (9 ± 2 °C and 40–60% relative humidity) conditions. With the advance of maturation, the reducing sugars and soluble solids concentrations increased, while that of the titratable acidity and ascorbic acid contents decreased. The half-ripe fruits could be stored at refrigerated conditions for a longer period (10 days) when compared with the fruits stored at ambient conditions (only 6 days) without presenting any sign of senescence in the fruit. The higher index of °brix/acidity (6.81) in the fruits stored at refrigeration temperature for 10 days made these fruits much more appreciable from an organoleptic flavor standpoint when compared with fruits stored for only 6 days at ambient conditions.

Frutos de Umbu (Spondias tuberosa Arruda Câmara) fueron analizados por sus características físicas, físico-químicas y químicas en dos estados de maduración fisiológica (medio-maduro y maduro). Los frutos medio maduros fueron almacenados en diferentes condiciones: (1) ambiente (27 ± 2 °C y 60–75% de humedad relativa) y (2) refrigeración (9 ± 2 °C y 40–60% de humedad relativa). Con el avance de la maduración la concentración de azúcares reductores y sólidos solubles se vieron incrementados mientras la acidez titulable y ácido ascórbico se redujeron. Los frutos medio maduros pudieron ser almacenados a condiciones de refrigeración por un período más largo (10 días) si se compara con los frutos almacenados a condiciones ambiente durante sólo 6 días sin presentar ningún signo de senescencia. El alto índice de °brix/acidez (6,81) en frutos almacenados a temperatura de refrigeración durante 10 días hizo esos frutos ser mucho más apreciados desde el punto de vista de sabor organoléptico cuando se compara con frutos almacenados durante sólo 6 días en condiciones ambiente.

Keywords:

• chemical analysis
• fatty acids
• maturity
• refrigeration
• Spondias tuberosa
• tropical fruit

Palabras clave:

• análisis químico
• ácidos grasos; madurez
• refrigeración
• Spondia tuberosa
• fruta tropical

Introduction

Umbu (Spondias tuberosa Arruda Câmara) plant is adapted to a hot tropical climate and is extremely tolerant to drought, being resistant to temperatures as low as −2 °C. In Brazil, umbu fruits are mainly commercialized either as fresh fruit or in the form of frozen fruit pulp.

Very little scientific information on the effect of physiological conditions of umbu fruits on its post-harvest behavior is available. Silva, Pires, and Silva (1987) studied the phenological characteristics of umbu trees, relating this to the genetic variations existent in different municipalities of Taperoá e Teixeira in the state of Paraíba. Chaves, Nóbrega, Vieira, and Regis (1971) presented some data on physical and chemical analyses of ripe umbu fruit while Narain, Bora, Holschuh, and Vasconcelos (1992), studying the variations in physical and chemical composition during maturation of umbu fruit, reported that the fruits are round to ovoid in shape (3.2 cm long and 2.9 cm in width) and their pH and reducing sugars increased with the advance in their maturity. However, there is lack of information on physico-chemical characteristics of the fruit at different stages of its physiological maturity on its post-harvest storage at different conditions, particularly that of refrigeration.

The storage of fruits including tropical and subtropical fruits under refrigerated conditions is a domestic practice until its consumption. The method is mostly used to increase the shelf life of the fruits and vegetables by reducing its metabolism and weight loss (Chitarra & Chitarra, 2006). Usually, the tropical fruits stored in ambient conditions at temperature higher than 25 °C characterize for lower shelf life and thereby reducing its commercial value (Kader et al., 1985). Thus, storage under refrigeration conditions can be a better option to reduce post-harvest losses in ripe fruits while maintaining its quality and increasing the shelf life of the fruit.

As there are no studies undertaken on evaluating the post harvest behavior on physico-chemical characteristics of umbu fruit stored at refrigerated conditions, the objective of the current study was to determine changes in the physico-chemical and chemical characteristics of the umbu fruit at different stages of its maturity (half-ripe and ripe) and to verify the effect of its physiological maturity (half-ripe fruits) on physico-chemical characteristics of fruits stored at ambient and refrigerated conditions.

Materials and methods

Fruits classification and storage

The umbu (Spondias tuberosa Arruda Câmara) fruits were harvested at the Experimental Station of the IPA – Instituto de Pesquisas Agropecuárias of the state of Pernambuco, situated in the city of Itambé, Brazil. The fruits were harvested manually and transported to the Laboratory of Chemical Analysis of Foods at Federal University of Paraíba, João Pessoa, Brazil. At the laboratory, the fruits were washed in chlorinated water (10 mg L⁻¹ of available chlorine), selected and classified into two stages of its physiological maturity (half-ripe and ripe) according to the criteria presented in Table 1. The classification of fruits for the green maturity stage according to these criteria led to the selection of fruits with hard firmness and hence pulp extraction from these fruits was very difficult in domestic mixer. Therefore, in this work only half-ripe and ripe fruits were considered for the physico-chemical analysis. Half-ripe fruits were stored at ambient (27 ± 2 °C and 60–75% relative humidity) and at refrigerated (9 ± 2 °C and 40–60% relative humidity) conditions.

Table 1. Criteria for classification of maturation stage of umbu fruit.
Tabla 1. Criterios para la clasificación del estado de maduración del fruto umbu.

Characteristic	Stage of maturity
	Green	Half-ripe	Ripe
Prominent skin color	Green	Yellowish-green	Greenish yellow
Texture	Hard	Semi-hard	Soft
Pulp extraction	Difficult	Normal	Easy

Physical analysis

Ten lots of fruits classified according to the stage of maturity (half-ripe and ripe stages) wherein each lot consisted of five fruits were analyzed individually for physical characteristics. Length and diameter were measured with a vernier calliper, and volume by the displacement of the liquid. The measurement of length was made in the polar axis of fruit, i.e. between apex and stem. The maximum width of the fruit, measured in the direction perpendicular to the polar axis, was considered as diameter. The weight retention (% difference between the initial and final weight) was verified daily for both half-ripe and ripe fruits during storage at ambient conditions (27 ± 2 °C and 60–75% relative humidity) and at refrigeration (9 ± 2 °C and 40–60% relative humidity).

Physico-chemical and chemical analysis

The edible portion of the fruit was separated manually from the seed using a stainless steel knife, and triturated in a domestic mixer to obtain a uniform suspension. Five different samples obtained from fruits of each maturity (half-ripe and ripe) were analyzed in triplicate. The chemical analyses were realized of the fruits stored at ambient conditions on days 1, 2, 4 and 6 of storage while for fruits stored at refrigeration conditions, the analyses were performed on days 1, 2, 4, 6, 8 and 10 of storage. Moisture, lipid, starch, pectin, titratable acidity, pH, total sugars, reducing sugars, and ascorbic acid contents were determined according to the standard methods described by Ranganna (1991). The total soluble solids, crude fiber and ash contents were determined following the standard AOAC (2002) procedure. The protein content was determined by the Kjeldahl method described by IAL (1985).

Fatty acid composition of pulp oil

The oil was obtained from the pulp by extraction with n-hexane using soxhlet apparatus. Fatty acids were transformed to their methyl esters (FAME) following the method of Hartman and Lago (1973) and were determined by using a gas chromatograph (Hewlett Packard HP 5890 Series II) equipped with a flame ionization detector. Varying volumes (1.0 μL and 1.5 μL) of FAME were injected and GC separation was carried out on HP INNOwax capillary column (Hewlett Packard; 30 m length, 0.25 mm i.d. and 0.25 μm film thickness). The carrier gas (ultra high purity helium, 99.999%) head pressure was maintained at 11.5 psi and the column flow rate was 1 mL/min. The oven temperature was held initially at 120 °C for 1 min, thereafter increased at 8 °C/min to 210 °C and then maintained at 210 °C for 45 min. The temperatures of the injection port and of detector were 250 and 280 °C, respectively. FAMEs were positively identified by comparison with the data obtained by running the authentic FAME standards obtained from various firms (Sigma/Aldrich; Nu-Chek-Prep, USA) on a GC-MS system (Varian 4000MS System) run under identical analytical conditions.

Statistical analysis

The statistical analysis was performed using SAS software (SAS Institute, Cary, NC) Version 9.1.3. Significant differences between the mean values of different characteristics were determined by applying Tukey´s test for multiple comparisons at the probability of 5% (p ≤ 0.05).

Results and discussion

The results of physico-chemical and chemical characteristics of umbu fruit at half-ripe and ripe stages of maturity are presented on Table 2. The umbu fruit with advance of maturity tends to attain a round form as observed from the values of length/diameter ratio. The average weight of umbu fruit was found to be significantly different between half-ripe and ripe fruits, the weight being lower in ripe fruits (18.7 g) when compared with those of half-ripe fruits (20.28 g). The pulp yield of the fruits was also found to be significantly different between the two stages of maturity, the yield being higher in ripe fruits (57.9%) when compared with the fruits of half-ripe stages (52.8%).

Table 2. Physical, physico-chemical, and chemical characteristics (mean ± standard deviation) of umbu fruit at different stages of its physiological maturity.
Tabla 2. Características físicas, físico-químicas y químicas (promedio ± desviación estándar) del fruto de umbu a diferentes estados de su maduración fisiológica.

Parameter	Apparent maturity
	Half-ripe	Ripe
Physical characteristics
Length of fruit (cm)	3.72^a ± 0.16	3.46^a ± 0.10
Diameter of fruit (cm)	3.09^b ± 0.03	2.93^a ± 0.03
Length/diameter	1.21^a ± 0.04	1.18^a ± 0.03
Length of seed (cm)	2.24^b ± 0.01	2.18^a ± 0.02
Width of seed (cm)	1.55^b ± 0.03	1.41^a ± 0.05
Weight of fruit (g)	20.28^b ± 0.23	18.70^a ± 0.72
Weight of pulp (g)	10.70^a ± 0.03	10.83^a ± 0.43
Weight of pulp (%)	52.78^a ± 0.48	57.88^b ± 0.09
Weight of seed (g)	3.61^b ± 0.10	2.99^a ± 0.10
Weight of seed (%)	17.78^b ± 0.30	15.99^a ± 0.11
Weight of skin (g)	5.97^b ± 0.11	5.09^a ± 0.19
Weight of skin (%)	29.44^b ± 0.20	27.20^a ± 0.07
Volume of fruit (mL)	17.83^a ± 0.58	16.77^a ± 0.50
Density of fruit (g/cm^3)	1.14^a ± 0.04	1.12^a ± 0.01
Physico-chemical characteristics
pH	2.23^a ± 0.04	2.72^b ± 0.04
Degree brix	7.9^a ± 0.1	9.7^b ± 0.2
Acidity (expressed as % citric acid)	2.48^b ± 0.02	1.29^a ± 0.01
°Brix/acidity	3.17^a ± 0.06	7.56^b ± 0.04
Chemical characteristics
Moisture (g/kg)	888.3^a ± 0.25	895.9^b ± 0.14
Ash (g/kg)	2.5^a ± 0.01	3.4^b ± 0.04
Lipids (g/kg)	8.4^a ± 0.04	8.9^a ± 0.04
Fiber (g/kg)	9.5^a ± 0.02	10.4^b ± 0.02
Protein (g/kg)	2.1^a ± 0.01	2.9^b ± 0.02
Reducing sugars (g/kg)	16.6^a ± 0.01	28.1^b ± 0.15
Total sugars (g/kg)	27.8^a ± 0.04	34.9^b ± 0.21
Starch (g/kg)	12.5^b ± 0.05	10.7^a ± 0.08
Calcium pectate (g/kg)	10.7^b ± 0.08	9.3^a ± 0.03
Ascorbic acid (mg/kg)	156.8^b ± 0.04	144.7^a ± 0.06
Notes: Means in each row followed by different superscript letters were significantly different (p ≤ 0.05).Standard deviation (SD) <0.01 is reported as 0.01. Notas: Promedios en cada fila seguidos de diferente letra en el superíndice fueron significativamente diferentes (p ≤ 0,05).Desviación estándar (SD) <0,01 se indica como 0,01.

The pH of the fruits increased from 2.2 in the half-ripe fruits to 2.7 in ripe fruits. The pH and acidity, both characteristics were significantly different in fruits of the two stages of maturity. These values are lower than the values reported earlier (Narain et al., 1992). The total soluble solids content increased with maturity from 7.9 to 9.7 °brix. The values of the ratio of °brix and acidity were also found to be lower, 3.2 for half-ripe and 7.6 for ripe fruits when compared with the values 8.5 for half-ripe and 9.5 for ripe fruits found by Costa, Luz, Gonçalves, and Bruno (2004). The reducing sugars content were significantly different among the fruits of two maturities. The values of reducing sugars found in this work, being significantly different between fruits of half-ripe and ripe stages, are extremely lower (1.7 for half-ripe and 2.8 for ripe fruits) than in the work reported earlier (4.1 for half-ripe and 5.3 for ripe fruits) by Narain et al. (1992). However, the ascorbic acid content was almost the same (15.7 mg/100 g for half-ripe and 14.5 mg/100 g for ripe fruits). On the basis of reducing sugars content of half-ripe and ripe fruits it is concluded that the fruits used in this study were very much different in over all taste characteristics as compared to umbu fruits worked earlier. It is important to note that the fruits obtained for the study performed earlier by Narain et al. (1992) were from an interior region located in the city of Pombal in the state of Paraiba while the fruits obtained in this study were from the Experimental Station administered by IPA, Recife, in the state of Pernambuco where other soil and climatic factors could have had an impact on the chemical quality of fruits.

The data on the evaluation of physico-chemical and chemical characteristics of umbu fruits at half-ripe stage of maturity when the fruit was stored at ambient (27 ± 2 °C and 60–75% relative humidity) and refrigerated (9 ± 2 °C and 40–60% relative humidity) conditions are presented in Tables 3 and 4. It was observed that the fruit stored at ambient conditions had the maximum shelf-life of 6 days while the fruits stored at refrigerated conditions had a prolonged shelf-life of 10 days. To compare the behavior of fruits stored at two different conditions, the data on some important characteristics such as weight loss and °brix/acidity ratio, which had noticeable changes are better represented in Figure 1.

Figure 1. Brix/acidity ratio and weight loss (%) of umbu fruit pulp at ambient and refrigerated conditions.

Figura 1. Relación °brix/acidez y perdida de peso de la pulpa de fruta de umbu en condiciones ambiente y refrigeración.

Table 3. Physico-chemical and chemical characteristics of umbu fruits stored at ambient (27 ± 2 °C and 60–75% relative humidity) and refrigerated (9 ± 2 °C and 40–60% relative humidity) conditions.
Tabla 3. Características físico-químicas y químicas de frutos de umbu almacenados a condiciones ambiente (27 ± 2 °C y 60–75% de humedad relativa) y refrigeración (9 ± 2 °C y 40–60% de humedad relativa).

Storage period (days)	°Brix		Acidity (expressed as % citric acid)		pH
	Ambient	Refrigerated	Ambient	Refrigerated	Ambient	Refrigerated
0	7.9^a,A ± 0.1	7.9^a,A ± 0.10	2.48^c,A ± 0.02	2.48^d,A ± 0.02	2.23^a,A ± 0.04	2.23^a,A ± 0.04
1	7.9^a,A ± 0.0	8.0^a,A ± 0.01	2.49^c,B ± 0.04	2.37^d,A ± 0.01	2.18^a,A ± 0.17	2.18^a,A ± 0.03
2	8.0^a,A ± 0.1	8.0^a,A ± 0.10	2.00^b,A ± 0.06	2.45^d,B ± 0.04	2.39^a,b,A ± 0.03	2.34^a,b,A ± 0.06
4	8.2^a,b,A ± 0.1	8.8^c,B ± 0.01	1.92^a,b,A ± 0.01	1.95^b,A ± 0.04	2.43^a,b,A ± 0.04	2.48^b,c,A ± 0.04
6	8.4^b,A ± 0.1	9.0^c,d,B ± 0.01	1.79^a,B ± 0.04	1.38^a,A ± 0.01	2.66^bA ± 0.06	2.56^c,d,A ± 0.04
8	–	9.0^c,d ± 0.01	–	1.29^a ± 0.03	–	2.62^d ± 0.04
10	–	9.7^d ± 0.10	–	1.29^a ± 0.07	–	2.70^d ± 0.07
Notes: Means in each column followed by different superscript small letters were significantly different (p ≤ 0.05) and means in each row, for each characteristic, followed by different superscript capital letters were significantly different (p ≤ 0.05).Standard deviation (SD) <0.01 is reported as 0.01. Notas: Promedios en cada columna seguidos de letras pequeñas en el superíndice fueron significativamente diferentes (p ≤ 0.05).Desviación estándar (SD) <0.01 se indica como 0.01.

Table 4. Physico-chemical characteristics of umbu fruits stored at ambient (27 ± 2 °C and 60–75% relative humidity) and refrigerated (9 ± 2 °C and 40–60% relative humidity) conditions.
Tabla 4. Características físico-químicas de frutos de umbu almacenados a condiciones ambiente (27 ± 2 °C y 60–75% de humedad relativa) y refrigeración (9 ± 2 °C y 40–60% de humedad relativa).

Storage period (Days)	Ascorbic acid (mg/kg)		Total sugars (g/kg)		Reducing sugars (g/kg)
	Ambient	Refrigerated	Ambient	Refrigerated	Ambient	Refrigerated
0	156.8^d,A ± 0.04	156.8^d,A ± 0.04	27.8^b,A ± 0.04	27.8^a,A ± 0.04	16.6^a,A ± 0.01	16.6^a,A ± 0.01
1	153.7^c,A ± 0.04	156.0^d,B ± 0.06	23.3^a,A ± 0.07	27.2^a,B ± 0.11	17.0^a,B ± 0.04	15.1^a,A ± 0.08
2	151.2^b,c,A ± 0.07	154.4^d,B ± 0.03	28.7^b,A ± 0.04	31.4^b,B ± 0.07	18.2^a,B ± 0.10	16.8^a,A ± 0.01
4	150.3^b,B ± 0.07	148.8^c,A ± 0.03	32.7^c,A ± 0.11	34.0^b,c,A ± 0.13	27.3^b,B ± 0.04	19.7^b,A ± 0.04
6	148.8^a,B ± 0.03	134.1^b,A ± 0.13	34.7^c,A ± 0.11	37.2^c,d,A ± 0.10	29.4^b,B ± 0.3	21.9^b,A ± 0.08
8		132.2^a,b ± 0.04		37.9^d,e ± 0.06		26.5^c ± 0.06
10		131.2^a ± 0.04		41.3^e ± 0.07		28.3^c ± 0.08
Notes: Means in each column followed by different superscript small letters were significantly different (p ≤ 0.05) and means in each row, for each characteristic, followed by different superscript capital letters were significantly different (p ≤ 0.05).Standard deviation (SD) <0.01 is reported as 0.01. Notas: Promedios en cada columna seguidos por letra minúscula en el superíndice fueron significativamente diferentes (p ≤ 0.05) y promedios en cada fila, para cada característica, seguidos por mayúscula en el superíndice fueron significativamente diferentes (p ≤ 0.05).Desviación estándar (SD) <0.01 se indica como 0.01.

It is observed from Figure 1 that weight loss of fruits stored at ambient conditions was higher in the initial period of storage when compared with the fruits stored at refrigerated conditions. However, on 4 days of storage the weight loss of the fruits was the same (5.1%) for the fruits, stored either at ambient or refrigerated conditions. The fruits stored at ambient conditions had a higher weight loss (8%) on 6 days of storage thereafter the fruits entered senescence phase. However, the fruits stored at refrigerated temperature had a lower weight loss, being only 7.6% on 10 days of storage (Figure 1).

The ratio of °brix and acidity in the fruits stored at refrigeration temperature was almost the same for the first 2 days at both the storage conditions (Table 3). However on further storage, this ratio had a sharp increase in fruits stored at refrigerated temperature up to a period of 10 days. The reducing sugars pattern had wide difference between the fruits stored at ambient and refrigeration conditions, although the final values been almost the same (2.9%) for the fruits stored for 6 days at ambient conditions and 2.8% for fruits stored for 10 days at refrigeration conditions (Table 4).

The pulp pH increased with the advance in maturity of the fruit, varying from 2.2 to 2.7 for fruits stored at ambient conditions (Table 3). A similar trend was found also for the fruits stored at refrigerated conditions. These relatively lower pH values characterized the acid flavor of the pulp. Accompanying the pH values, the soluble solids (°brix), total sugars and reducing sugars increased with advances in maturity while the titratable acidity decreased. The °brix/acid ratio increased from 3.17 to 4.69 and from 3.18 to 7.56 for the fruits stored at ambient and refrigerated conditions, respectively (Figure 1). In a study performed on 19 genotypes of a hybrid species of cajá-umbu (Spondias spp.), Lira Junior et al. (2005) reported, on an average, fruits possessing 2.2 pH; 14.8 °brix and the ratio of °brix/acidity of 9.05. In other study undertaken on cajá (Spondias mombim L.) fruits analyzing 30 genotypes, on an average, the values of pH were 2.61, °brix 11.01 and the ratio of °brix and acidity of 11.03. These data relating other species of the same genus, Spondias are quite different, demonstrating the inherent characteristic of umbu fruit, being prominently astringent in taste.

The higher values of °brix/acidity ratio in the fruits stored at refrigerated conditions for periods varying from 6 to 10 days leads us to conclude that these fruits are very much appreciated organoleptically on storage at refrigerated conditions.

The fatty acids composition of the ripe and half-ripe umbu pulp oil is presented in Table 5 while the total values of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) besides their indices such as MUFA/SFA, PUFA/SFA and UFA/SFA are presented in Table 6. A very large number (26) of FAMEs were identified in pulp oils of the ripe and half-ripe umbu pulp. The SFA accounted for about 60.1 and 63.7% of the total fatty acids for half-ripe and ripe fruits, respectively. Hexadecanoic acid, octadecanoic acid, and pentadecanoic acids were the principal SFAs in umbu pulp obtained from fruits of both maturities.

Table 5. Fatty acids composition (% total fatty acids; mean value ± standard deviation) obtained from pulp of umbu fruits at different stages of maturity.
Tabla 5. Composición en ácidos grasos (% del total de ácidos grasos; valor medio ± desviación estándar) obtenida de la pulpa de frutos de umbu a diferentes estados de maduración.

Fatty acid		Stage of fruit maturity
		Half-ripe	Ripe
Saturated fatty acids (SFA)		60.12^a ± 0.11	63.85^b ± 0.25
n-Hexanoic acid	C6:00	Nd	Tr
n-Heptanoic acid	C7:0	Tr	Tr
n-Octanoic	C8:0	0.11^a ± 0.01	0.13^a ± 0.02
n-Nonanoic acid	C9:0	Tr	Tr
n-Decanoic acid	C10:0	0.21^a ± 0.01	0.24^b ± 0.01
n-Undecanoic acid	C11:00	0.50^a ± 0.04	0.55^a ± 0.03
n-Dodecanoic acid	C12:0	0.46^a ± 0.05	0.51^a ± 0.11
n-Tridecanoic acid	C13:0	0.38^a ± 0.01	0.40^a ± 0.04
n-Tetradecanoic acid	C14:0	0.50^a ± 0.02	0.69^b ± 0.08
n-Pentadecanoic acid	C15:0	11.87^a ± 0.23	13.23^b ± 0.12
n-Hexadecanoic acid	C16:0	29.08^a ± 0.11	30.43^a ± 1.24
n-Heptadecanoic acid	C17:0	0.48^a ± 0.05	0.51^a ± 0.07
n-Octadecanoic acid	C18:0	12.66^a ± 0.31	13.01^a ± 1.23
n-Nonadecanoic acid	C19:0	Tr	Tr
n-Eicosanoic acid	C20:0	0.99^a ± 0.05	1.13^a ± 0.09
n-Doeicosanoic acid	C22:0	2.88^a ± 0.01	3.01^b ± 0.01
Mono-unsaturated fatty acids (MUFA)		33.91^b ± 0.17	30.84^a ± 0.09
9-Tetradecenoic acid	C14:1	1.63^b ± 0.02	1.18^a ± 0.11
10-Pentadecenoic acid	C15:1	0.51^a ± 0.01	0.41^a ± 0.07
9-Hexadecenoic acid	C16:1	0.81^a ± 0.06	0.78^a ± 0.01
10-Heptadecenoic acid	C17:1	0.11^a ± 0.08	0.09^a ± 0.02
9-Octadecenoic acid	C18:1	29.91^a ± 1.02	27.49^a ± 0.21
11-Eicosenoic acid	C20:1	0.73^a ± 0.03	0.70^a ± 0.01
13-Docosenoic acid	C22:1	0.21^a ± 0.01	0.19^a ± 0.01
Poly-unsaturated fatty acids (PUFA)		5.31^a ± 0.05	5.97^b ± 0.1
9,12-Octadecadienoic acid	C18:2	4.27^a ± 0.12	4.82^b ± 0.09
9,12,15-Octadecatrienoic acid	C18:3	0.44^a ± 0.00	0.49^b ± 0.01
11,14,17-Eicosatrienoic acid	C20:3	0.60 ± 0.02	0.66^b ± 0.02
Notes: Tr stands for trace level (less than 0.01% of total fatty acids).Nd, not detected.Means in each row followed by different superscript letters were significantly different (p ≤ 0.05). Standard deviation (SD) <0.01 is reported as 0.01. Notas: Tr se mantiene para el nivel de trazas (menos de 0,01% de ácidos grasos).Nd = no detectado.Promedios en cada fila seguidos por diferentes letras en el superíndice fueron significativamente diferentes (p ≤ 0,05). Desviación estándar (SD) <0,01 se indica como 0,01.

Table 6. Saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids profile (mean value ± standard deviation) of half-ripe and ripe pulp oils of umbu fruit.
Tabla 6. Perfil de ácidos grasos saturados (SFA), monoinsaturados (MUFA) y poliinsaturados (PUFA) (valor medio ± desviación estándar) de aceites de pulpa de fruto de umbu medio maduro y maduro.

Fatty acids	Stages of fruit maturity
	Half-ripe	Ripe
SFA (% of total fatty acids)	60.12^a ± 0.11	63.85^b ± 0.25
MUFA (% of total fatty acids)	33.91^b ± 0.17	30.84^a ± 0.09
PUFA (% of total fatty acids)	5.31^a ± 0.05	5.97^b ± 0.10
MUFA/SFA	0.56	0.53
PUFA/SFA	0.09	0.09
UFA/SFA	0.65	0.62
Note: Means in each row followed by different superscript letters were significantly different (p ≤ 0.05). Nota: Promedios en cada fila seguidos de diferente letra en el superíndice fueron significativamente diferentes (p ≤ 0,05).

The total contents of MUFA in pulp oils were 33.9% for half-ripe and 30.8% for ripe umbu fruits. 9-Octadecenoic acid was the principal fatty acid, representing about 88% of the total MUFA in half-ripe and ripe fruits. Among the PUFA, 9,12-octadecadienoic acid was present in higher concentrations being 4.27 to 4.82% of the total fatty acids. However, the over-all quality of oil obtained from the pulp of fruits of both maturities (half-ripe and ripe stages) did not differ. No comparison could be made of these results as no data reporting the identification of fatty acids in pulp oil of umbu fruits is available.

Acknowledgements

The authors thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil for awarding fellowship and financing this work. The authors wish to thank the Head of the Estação Experimental de Itambé located at Itambé-PE, pertaining to the Empresa Pernambucana de Pesquisa Agropecuária for supplying umbu fruits.