2025 Volume 94 Issue 2 Pages 190-199
Fruit consumption is highly recommended due to its health benefits. Passiflora species are a good source of vitamins and antioxidant compounds such as carotenoids that are associated with a reduction in cellular oxidative processes, as well as against cardiovascular diseases and cancer development. As a result, purple passion fruit (P. edulis) and yellow passion fruit (P. edulis f. flavicarpa) are economically important crops that are cultivated based on the demand for their flavor and nutraceutical properties. The objective of this study was to determine the components of carotenoids and sugars in the pulp juice of passion fruit. Two Ecuadorian yellow passion fruit strains (‘INIAP 2009’ and ‘POR1’), one Ecuadorian purple passion fruit variety (‘Gulupa’) and two Asian hybrid cultivars (P. edulis × P. edulis f. flavicarpa; ‘Summer Queen’ and ‘Ruby Star’) were used for this research. The results showed that ‘POR1’ had high acidity and contained all carotenoids, but had the lowest amount of vitamin C, whereas ‘INIAP 2009’ had high contents of organic acids, vitamin C and β-cryptoxanthin. ‘Gulupa’ had the lowest acidity, α-carotene and citric acid content, but the highest amount of glucose, fructose, malic acid and vitamin C; this variety also showed high values of β-carotene and β-cryptoxanthin. On the other hand, ‘Summer Queen’ had high sucrose, malic acid, α and β-carotene and good amount of vitamin C, while ‘Ruby Star’ had high amounts of α-carotene, β-cryptoxanthin and citric acid, but low vitamin C content. These results can be used for further breeding programs focused on improving passion fruit quality.
Passion fruit (Passiflora spp.) is an economically important crop that is cultivated because of the demand for its flavor and nutraceutical properties (Viera et al., 2022a, b). This fruit is now produced worldwide in countries such as Ecuador, Colombia, Peru, Japan, China, New Zealand, Australia, Kenya, among others (Ocampo et al., 2013; Santos and Gilreath, 2006; Viera et al., 2020). The yellow passion fruit (P. edulis f. flavicarpa) is preferred in South American countries and is mainly used for juice making and concentrate elaboration (Viera et al., 2020), while the purple cultivar (P. edulis f. edulis) is preferred for fresh consumption in Europe, Oceania and Asia (Ortiz et al., 2012). Demand has been increasing in the several last years.
Worldwide, around 600 Passiflora species have been described, and 120 of them are native to Brazil (Barbosa Santos et al., 2021). The main commercial cultivated species are purple passion fruit, yellow passion fruit and their hybrids, and they all have phenotypical differences. ‘INIAP 2009’ (yellow type) comes from a mass selection process carried out in Ecuador from a Brazilian passion fruit germplasm (Valarezo Concha et al., 2009), while ‘POR1’ is a yellow local strain that has not been improved by breeding, but is grown by a big proportion of the Ecuadorian farmers due to its pulp yield. ‘INIAP 2009’ and ‘POR1’ are open-pollinated strains; therefore, their progenies are considered half-siblings because they allow fertilization by a mixture of pollens during pollination (Meneses Cordeiro et al., 2020).
They are grown in the tropical area of the country (mainly Manabí) at an altitude of around 52 meters above sea level (masl). ‘Gulupa’ is a self-compatible purple passion variety, which also originates from Brazil but has been widely cultivated in Colombia (Hernández and Fischer, 2009). From Colombia, it was introduced to Ecuador, where it is cultivated in the highlands (around 2,300 masl), although to a lesser extent than the yellow variety. On the other hand, Asian self-compatible passion fruit hybrid cultivars such as ‘Summer Queen’ and ‘Ruby Star’ are grown in Japan, especially in the Kagoshima area. ‘Summer Queen’ comes from a cross between P. edulis Sims × P. edulis f. flavicarpa Derg. It was developed by breeding at the Agriculture Experimental Site of Kyushu in Japan (Yonemoto and Kondo, 2020). On the other hand, ‘Ruby Star’ (which resembles the Taiwanese cultivar ‘Tai-nung #1’) was likely bred by the Tropical Fruit Horticulture Site of Fongshan in Taiwan (Yonemoto and Kondo, 2020), and was brought to Amami Oshima, Japan where it has been cultivated since the 1980s and named there in 2000 (Iwai and Omatsu, 2002).
Physical and chemical characterization of passion fruit can identify elite traits in the different passion fruit cultivars and this germplasm can be used as a primary source for breeding processes. In addition, fruit chemical composition is an essential factor to add value and promote passion fruit consumption as a nutraceutical source of biocompounds such as carotenoids, sugars, organic acids and vitamin C (Viera et al., 2022a).
There is wide effort to obtain reliable analytical data on bioactive compounds such as carotenoids due to the various beneficial functions and effects on human health attributed to them (Britton, 2020). α-carotene is widely found in dietary fruits and it is associated with the prevention of cancer, cardiovascular diseases as well as protecting human skin against cell oxidation (Zhao et al., 2022). β-carotene is an essential source of vitamin A (Toti et al., 2018) and passion fruit is a good source of this carotene (Barbosa Santos et al., 2021). β-cryptoxanthin is an oxygenated carotenoid that seems to be absorbed more than other carotenoids (Burri et al., 2016). It exists in a limited number of species that have orange-colored fruits (Dias et al., 2018). This carotenoid may have anticarcinogenic properties, principally related to lung cancer, and may prevent osteosporosis due to its anabolic effect on bone (Burri et al., 2016). Therefore, knowing the amount of these three types of carotenoids in different passion fruit genotypes will allow identification of elite germplasms that could be used for breeding programs focused on improving carotenoid content, specially β-cryptoxanthin due to its benefits for human health.
Consequently, the objective of this study was to determine the components of carotenoids and sugars of three Ecuadorian and two Asian passion fruit strains/varieties/cultivars grown in Japan under greenhouse conditions to clarify their characteristics in terms of fruit taste and human health.
This research was carried out in the Laboratory of Plant Production Science of the Tokyo University of Agriculture (latitude 35°38′33′′, longitude 139°37′48′′). Two yellow passion fruit strains (‘INIAP 2009’ and ‘POR1’), one Ecuadorian purple passion fruit variety (‘Gulupa’) and two Asian hybrid cultivars (‘Summer Queen’ and ‘Ruby Star’) were used for this study (Fig. 1).
Passion fruit (upper pictures) and their juice (lower pictures). A. ‘INIAP 2009’ (P. edulis f. flavicarpa), B. ‘POR1’ (P. edulis f. flavicarpa), C. ‘Gulupa’ (P. edulis f. edulis), D. ‘Summer Queen’ (P. edulis × P. edulis f. flavicarpa), E. ‘Ruby Star’ (P. edulis × P. edulis f. flavicarpa).
‘INIAP 2009’, ‘POR1’ and ‘Gulupa’ fruits came from plants harvested from seeds (progeny), while ‘Summer Queen’ and ‘Ruby Star’ fruits were obtained from plants propagated by cuttings. All passion fruit plants were grown in the greenhouse of Tokyo University of Agriculture in Setagaya, Tokyo. Five plants for each passion fruit strain/variety/cultivar were transplanted on October 2021 to 20 L pots to grow them, and after that transplanted to large pots (60 L) on April 2022. Flowering started in the middle of June for the Ecuadorian yellow passion fruit strains, and from the beginning of June for the Ecuadorian purple passion fruit variety and Asian cultivars. Harvest started at the beginning of August for the Ecuadorian yellow passion fruit strains and Asian cultivars, and from the middle of August for the Ecuadorian purple passion fruit variety.
Akadama soil (granular clay, Japanese volcanic soil) and manure compost (7:3 proportion) were used for plant growing. Irrigation was twice a day (4 L·plant·day−1) and liquid fertilizer (260 ppm of N, 120 ppm of P2O5, 405 ppm of K2O, 60 ppm of MgO, 1.5 ppm of Mn, 1.5 ppm of B2O3, 230 ppm of CaO, 2.7 ppm of Fe, 0.03 ppm of Cu, 0.09 ppm of Zn, and 0.03 ppm of Mo) was applied twice a week. Plants were trained vertically up to a height of 1.8 m and grew round, then downward branches were obtained by pruning for fruit production. Manual pollination using pollen from the ‘Ruby Star’ cultivar was done to obtain fruit set for ‘INIAP 2009’ and ‘POR1’, while self-pollination was used for ‘Gulupa’, ‘Summer Queen’, and ‘Ruby Star’. Electric fans were used to avoid excessive temperatures. The daily temperature in the greenhouse was about 27°C until the beginning of July, but it was not recorded thereafter. Usually, the daily maximum temperature exceeds 35°C and the minimum temperature does not fall below 20°C from August to September. The leaf-fruit ratio was not adjusted for the Ecuadorian strains/varieties, but was adjusted to about five for the Japanese cultivars. A plastic net was placed covering the fruits during development to avoid any mechanical damage due to fruit dropping. When the fruit dropped in the net, the fruits were harvested and the number of days from pollination until harvest was recorded.
Measurement of physical traitsPhysical traits were measured after fruit harvest. Fully colored ripe fruits were selected randomly each day up to a total of 18 fruits for each yellow and purple passion fruit type and characterized in terms of their physical traits. Fruit weight was calculated using a semi-micro analytical balance (GH-252; A&D Company, Tokyo, Japan), while diameter and peel thickness were recorded by digital calipers (CD-8 CB; Mitutuyo, IL, USA). Peel firmness (N) was calculated using a penetrometer (model 2519-104; Instron, MA, USA). Peel and pulp proportions, and seed yield were estimated by weighing each part and expressing the results as a percentage. Peel and pulp color were measured using the Hunter a, b and L scale with a Colorimeter (NR-3000; Nippon Denshoku Industries Co., Ltd., Tokyo, Japan).
Measurement of soluble solids content, acidity and vitamin CFive fruits of each strain/variety/cultivar (different from those used for measuring the physical traits) were harvested and kept at 25°C in dark conditions from 7 to 12 days depending on the strain/variety/cultivar to reach full ripening at a stage when up to 80% of the peel surface showed shrinkage (indicator of maturity), according to Viera et al. (2023). Relative humidity was not controlled during the ripening period. After that, these fruits were used to analyze the chemical traits, and sugar, organic acids and carotenoid content in the pulp. These were as follows: Soluble solids (SS) content (°Brix) and acidity (%) were recorded using a Brix-Acidity meter (Hybrid PAL-BX I ACID F5; Atago, Saitama, Japan), while pH was measured with a pH meter (LAQUAtwin-pH-11; Horiba, Kyoto, Japan). The sugar/acidity ratio (SAR) was determined using the relation between the total SS and the acidity. Vitamin C (ascorbic acid mg/100 g) was measured using a reflectometer (RQflex plus; Merck, Darmstadt, Germany) and ascorbic acid strips (Reflectoquant®; Merck, Darmstadt, Germany).
Quantification of sugarsFor all chemical quantification analyses, pulp samples were stored with nitrogen (N2) at −80°C in brown tubes to prevent oxidation and photlysis was used. For the sample extraction method, a column (Oasis; Waters, MA, USA) was used to remove contaminants. A 5 mL mixture of methanol and ultrapure water were passed in turn through the column with a syringe. After that, a 0.45 μm filter was attached to a syringe, and 5 mL of a sample diluted 100-fold with ultrapure water was collected in a brown bottle for high-performance liquid chromatography analysis (HPLC). Results are expressed as g/100 mL of pulp.
Quantification of organic acidsFor sample extraction, a column (Sep-pak; Waters, MA, USA) was used to remove contaminants, the pulp sample was diluted 50-fold with distilled water and the same processing as mentioned for the sugar analysis was carried out. Organic acid analysis was carried out using two columns (Shim-pack SCR-102H; Shimadzu, Tokyo, Japan). Quantification of organic acids was done by HPLC analysis. Results are expressed as g/100 mL of pulp.
Quantification of carotenoidsFor the carotenoid analysis, 1 mL of defrosted pulp sample from five fruits of each strain/variety/cultivar, was added to a brown plastic test tube (25 mL) with 300 mg of pyrogallol, 3 mL of ethanol, and 3 mL of potassium hydroxide solution (60%). Then, N2 was filled for 5 sec to prevent oxidation, and saponification was done in a hot bath (Personal-11; Taitec, Tokyo, Japan) at 80°C for 30 min. After saponification, the test tube was cooled at room temperature (25°C) with running water, 2 mL of ultrapure water and 6 mL of a mixed solvent of hexane ethyl acetate (9:1) were added. Then, the mixture was stirred in a vortex (VTX-3000L; LMS, Tokyo, Japan) for 1 min. The supernatant was transferred to a brown centrifuge plastic tube (10 mL of capacity), 1 mL of ultrapure water was added and it was stirred for 15 sec. The aqueous layer was removed, and 1 g of anhydrous sodium sulfate was added. The mixture was allowed to stand for 5 min for dehydration, and centrifugation was performed at 2,500 rpm for 5 min. After centrifugation, 3 mL of the organic solvent layer was transferred to another brown centrifuge plastic tube. For each procedure, N2 was added to prevent the oxidation of the sample. The sample solution was concentrated to dryness using a centrifugal evaporator (VC-960; Taitec, Tokyo, Japan). Next, 0.5 mL of ethanol was added to re-dissolve the dried product, and it was thereafter diluted 5-fold with methanol: acetonitrile (6:4). The analysis solution was passed through a 0.45 μL filter to obtain the sample for the quantification of α-carotene, β-carotene and β-cryptoxanthin by HPLC analysis. For the carotenoids analysis using HPLC (20A Series; Shimadzu, Tokyo, Japan), the mobile phase consisted of an organic solvent mixture of methanol and acetonitrite in a ratio of 6:4. The flow rate was set to 1.4 mL·min−1. The detection wavelength of the UV-VIS detector was set at 450 nm, and the column (Wakopak; Wakosil-II 5CISAR, Osaka, Japan) was maintained at 40°C during the analysis. Results are expressed as μg/100 mL of pulp fresh weight (FW).
Statistical analysisData analysis was carried out using R statistical software version 4.2.2. Skewness and Kurtosis tests were carried out to check data normality and a heteroscedasticity test was done with the data for each variable using the gvlma function of R. Square root transformation was applied for fruit weight while log10 was used to transform equatorial diameter, peel firmness, and SAR; however, results shown in the Tables refer to the original data for better understanding. A mean comparison (cultivar as classification factor) was carried out for the analyzed variables through a one-way ANOVA function of R. Tukey’s test at 5% was used to compare the passion fruit cultivars. The latter test was applied for the non-transformed and transformed data.
In addition, principal component analysis (PCA) was used to visualize the relationship among the chemical variables, and their association with the passion fruit cultivars.
Physical traits differed significantly between the yellow and purple types of passion fruits (Table 1). ‘INIAP 2009’ showed the greatest fruit weight, diameter and peel thickness, while ‘Gulupa’ exhibited the lowest fruit weight. ‘Gulupa’ and ‘Ruby Star’ showed the lowest peel thickness. All cultivars, except ‘Ruby Star’, achieved firmness over 10 N. ‘POR1’ and ‘Ruby Star’ produced desirable pulp yields above 50%. Ecuadorian passion fruits cultivated in a greenhouse in Tokyo had greater fruit weights compared to the same strains grown in an open field in Ecuador (Viera et al., 2020, 2022b). Asian cultivars had fruit weights comparable to those reported in previous studies carried out in Japan (Kondo and Higuchi, 2020; Nakayama and Matsuda, 2022). Peel thickness of the Ecuadorian passion fruits was comparable to open-field studies of the same strains (Viera et al., 2020, 2022b), although this trait can be influenced by environmental factors (Viera et al., 2020). Purple passion fruit hybrids had thinner peel (around 5.50 mm) than yellow cultivars, which is acceptable for fresh consumption (Nascimento et al., 1999). Farias et al. (2005) found that peel thickness is crucial when selecting promising materials, with breeders aiming for thinner peel and higher pulp yield. ‘Ruby Star’ and ‘POR1’ had high pulp yields (around 50%), making them potentially valuable strains and cultivars for commercial production (Tupinambá et al., 2012).
Physical fruit traits, yield characteristics, and number of days from pollination to harvesting of the yellow and purple passion fruit cultivars.
The period needed for passion fruit development varies among cultivars and it is influenced by environmental conditions (Hernández and Fischer, 2009; Shinohara et al., 2013a). ‘INIAP 2009’ and ‘POR1’ had the shortest pollination-to-harvest period, whereas ‘Gulupa’ had the longest (Table 1). Overall, passion fruit requires 60 to 70 days from pollination to maturation. Yellow passion fruits typically mature around 50 days after anthesis, while purple varieties take about 60 days (Rodríguez-Amaya, 2012). The results of this study aligned with these ranges. Yellow strains (‘INIAP 2009’ and ‘POR1’) thrive in temperatures between 23 to 25°C; however, they can adapt to 21 to 35°C (Valarezo et al., 2014). ‘Gulupa’ prefers a range from 16 to 24°C to grow (Pinzón et al., 2007). ‘Summer Queen’ and ‘Ruby Star’ are cultivated in Japanese greenhouses at 25 to 30°C, although summer temperatures can reach 40°C, causing cultivation challenges (Shimada et al., 2017). Yellow passion fruit strains had higher heat tolerance than the purple passion fruit cultivars. In this study, the Ecuadorian yellow strains were harvested around 45 days after pollination (DAP) (Table 1), similar to findings by Das et al. (2013). Asian cultivars were harvested around 63 DAP, with ‘Summer Queen’ potentially reaching 69 DAP in high temperatures (Shinohara et al., 2013b). ‘Gulupa’ took 75 DAP, shorter than the 91 DAP reported by Franco et al. (2013) at lower temperatures, suggesting that higher temperatures may influence early fruit drop (Shinohara et al., 2013b).
Peel and pulp color variations among passion fruit strains/variety/cultivars are presented in Table 2. Yellow strains showed similar peel color parameters, with no significant differences. ‘Ruby Star’ had a deeper red color and was lighter compared to other purple passion fruits. Pulp color was consistent among yellow strains. Of the purple passion fruits, ‘Gulupa’ had a lighter yellowish color and higher Chroma than Asian cultivars (Fig. 1). In passion fruit, purplish peel color has lower acidity, higher SS content and greater sugar/acidity ratio compared to yellowish color (Da Silva Araujo et al., 2017). These color differences highlight the distinct characteristics of each passion fruit strain/variety/cultivar.
Peel and pulp color of the yellow and purple passion fruit cultivars.
Chemical traits varied significantly among the evaluated passion fruit strains/variety/cultivars (Table 3). Asian cultivars had higher SS content compared to Ecuadorian purple and yellow passion fruit. ‘Ruby Star’ and ‘Summer Queen’ achieved the highest SS content, a valuable trait for both fresh consumption and industrial use. Yellow strains showed the highest acidity (above 2.40%), while ‘Gulupa’ had the lowest (1.21%). ‘Gulupa’ also demonstrated the highest SAR and pH. The pH of the Ecuadorian yellow strains was comparable to ‘Ruby Star’. Ecuadorian passion fruits grown in a greenhouse in Japan displayed similar chemical traits to those reported by Viera et al. (2020, 2022b) in open-field cultivation in Ecuador. However, yellow strains had higher SS content than those grown in an open-field in Brazil (Da Silva Araujo et al., 2017), highlighting the influence of agronomic management and cultivation conditions on chemical traits. Asian cultivars were similar to other greenhouse-grown fruits in Japan (Macha et al., 2006; Kondo and Higuchi, 2020; Shimada et al., 2020; Nakayama and Matsuda, 2022). Shimada et al. (2020) reported that ‘Summer Queen’ exhibited high SS content and SAR, but low acidity when ripened at 25°C, while ‘Ruby Star’ had favorable peel coloration at this temperature. They (loc. cit.) found that at 35°C, both cultivars tended to have yellowish peels and decreased SS content. In this study, ripening conditions were maintained at 25°C, resulting in a high SS content for both Asian cultivars and low acidity, particularly for ‘Gulupa’ and ‘Summer Queen’. These findings underscore the importance of temperature control in optimizing passion fruit quality.
Chemical traits, sugars, organic acids, carotenoids, and vitamin C content (fresh weight) of the yellow and purple passion fruit cultivars.
Sugars and organic acids are crucial quality indicators valued by consumers and the food industry (Nikolaou et al., 2017). Quantitative analysis of these compounds is essential for verifying the fruit quality index (Kelebek and Selli, 2011). Sugar composition analysis revealed that purple passion fruit cultivars contained higher levels of glucose and fructose than the yellow strains (Table 3). ‘INIAP 2009’ and ‘POR1’ had the lowest glucose content, while ‘Gulupa’, ‘Summer Queen’, and ‘Ruby Star’ had higher values. Fructose levels were also higher in these latter purple passion fruits. ‘Summer Queen’ had the highest sucrose content, while ‘Gulupa’ had the lowest. Notably, sucrose levels exceeded glucose in ‘INIAP 2009’, ‘POR1’, and ‘Summer Queen’. Previous studies have identified glucose as the primary sugar in yellow passion fruit (Ramaiya et al., 2013; Barbosa Santos et al., 2021). However, this trend was not observed in the Ecuadorian yellow strains evaluated in this study. Interestingly, glucose was the major sugar in purple passion fruit variety/cultivars. Fructose, known for its sweetness and influence on fruit taste (Yamaguchi et al., 1970), is a key factor in fruit quality and marketability (Nookaraju et al., 2010). In this study, purple passion fruit variety/cultivars had higher fructose content.
The major sugars in passion fruit (glucose, fructose, and sucrose) vary in quantity among species and cultivars (Fischer et al., 2018). Sugar proportions in passion fruit juice change during fruit maturation, even within the same cultivars (Shinohara et al., 2013b). Ramaiya et al. (2013) reported similar quantities of glucose and fructose in purple passion fruit, a tendency observed in both Ecuadorian as well as the Asian passion fruits in this study. Typically, sucrose is found in smaller amounts than glucose and fructose in ripe passion fruits (Ramaiya et al., 2013; Kondo et al., 2021). However, this trend was only observed in ‘Gulupa’ and ‘Ruby Star’ in the present study. These findings suggest that purple passion fruit and hybrid cultivars may have superior eating quality for fresh consumption. The variation in sugar content appears to be primarily genotype-dependent (Nookaraju et al., 2010), consistent with the differences observed between the yellow and purple types in this study. Given that fructose is twice as sweet as glucose, breeding efforts to increase the fructose/glucose ratio could improve fruit sweetness, flavor and overall eating quality (Levin et al., 2000). While the fructose-glucose ratio was close to 1 for all samples in this study, individual fructose concentration varied. This suggests that crossbreeding between them could potentially generate new varieties with improved sugar profiles.
Turning to organic acids (Table 3), ‘INIAP 2009’ had the highest citric acid content, whereas no statistical differences were observed in malic acid levels between Ecuadorian strains/variety and Asian cultivars. Organic acids are key components that determine fruit taste, flavor and quality (Zhang et al., 2021). In passion fruit pulp, citric and malic acids are the primary organic acids quantified (Barbosa Santos et al., 2021). Previous studies by Viera et al. (2022a) and Barbosa Santos et al. (2021) reported higher citric acid values (above 3.50 g/100 mL FW) in passion fruit strains grown in open field conditions in South America compared to those in this study. Higher temperatures during fruit development have been associated with increased organic acid content (Famiani et al., 2015); which may have influenced the results of this study. However, passion fruit storage at 25°C can lead to a 40% reduction in organic acid content due to acid metabolism and degradation (Maniwara et al., 2015).
Carotenoid content varied between the evaluated passion fruits (Table 3). ‘Summer Queen’ and ‘POR1’ had a high α-carotene content, while β-carotene levels were statistically similar across all strains/variety/cultivars. ‘POR1’ showed the highest amount of β-cryptoxanthin (1613.76 μg/100 mL). Fruits rich in α- and β-carotene are valuable for their antioxidant properties (Toti et al., 2018; Zhao et al., 2022). Passion fruit can be a source of β-carotene (Barbosa Santos et al., 2021). β-cryptoxanthin, important for human health due to its antioxidant properties, may reduce the risk of certain cancers and degenerative diseases (Burri et al., 2016). Pertuzatti et al. (2015) reported β-cryptoxanthin as the major carotenoid in yellow passion fruit, a trend observed in Ecuadorian yellow strains and ‘Ruby Star’, a yellow-purple hybrid. ‘POR1’ had the highest β-cryptoxanthin content, so it could be a good source of this carotenoid. However, due to its acidity, it is more suitable for juice processing than for fresh consumption, especially in Asian countries like Japan where purple passion fruit is mainly consumed fresh. Yano et al. (2005) reported lower β-cryptoxanthin levels (27.00 μg/100 mL) in purple passion fruit grown in Japanese greenhouse compared to the present study. Carotenoids content in passion fruit pulp depends on variables such as the crop system, climatic factors, and fruit maturation (Pertuzatti et al., 2015). In addition, carotenoids degrade during ripening, generating volatile compounds (Rodrígues Gómes et al., 2021). Conventionally managed passion fruits contained almost twice the β-cryptoxanthin of organically grown fruits, with light exposure and ripening control, influencing carotenoid levels (Pertuzatti et al., 2015). Pongener et al. (2013) found that carotenoid content in purple passion fruit increases during ripening when stored at 20°C, but decreases in later stages (20 days) due to pigment degradation. Therefore, optimizing cultivation and ripening conditions to enhance carotenoid content may be as crucial as breeding cultivars with genetically high carotenoid levels.
Passion fruit is a good source of ascorbic acid (vitamin C), with 100 g of fresh fruit supplying 50% of the daily recommended value (Biswas et al., 2021; Correa Cueva and Moreno Romero, 2018). Purple passion varieties often contain more vitamin C than the yellow ones (Ramaiya et al., 2013; Viera et al., 2022a). ‘Gulupa’ and ‘Summer Queen’ had the highest vitamin C content, while ‘POR1’ had the lowest. Previous research on yellow passion fruit grown in Brazil reported lower vitamin C levels than those found in Ecuadorian strains cultivated in Tokyo greenhouses (Barbosa de Oliveira et al., 2017; Barbosa Santos et al., 2021). Vitamin C content in passion fruit can vary depending on the temperature. Low temperatures promote vitamin C biosynthesis in passion fruit (Shimada et al., 2020). They (loc. cit.) found that ‘Summer Queen’ fruits at 15°C and ‘Ruby Star’ fruits at 25°C had higher ascorbic acid content than those at 35°C. Vitamin C degradation during storage is minimized at lower temperatures (6°C) compared to ambient conditions (25°C) (Viera et al., 2023).
PCA analysis (Fig. 2) revealed that the first two components explained 61.9% of the observed data variance. The first component contrasted glucose, fructose and vitamin C against citric acid and α-carotene, while the second component contrasted SS against β-cryptoxanthin. The PCA output indicated that ‘Summer Queen’ was characterized by high SS and sugar compounds (glucose, fructose, and especially sucrose); ‘POR1’ was associated with high β-cryptoxanthin content; ‘Gulupa’ was distinguished by high vitamin C and malic acid content.
Principal component analysis for the main chemical compounds in the different evaluated passion fruits. Small circles stand for the number of replications for each cultivar (n = 5) while the large circle represents the average value.
In conclusion, ‘POR1’ could serve as a valuable source of carotenoids for the food industry, particularly for juice production or concentrate manufacturing. ‘Ruby Star’, on the other hand, could be an option for carotenoid intake through fresh consumption. Based on these research findings, crossbreeding Ecuadorian and Asian passion fruit germplasms could be considered to develop new cultivars with enhanced fruit quality traits, particularly improved carotenoid content.
This research was funded by Tokyo University of Agriculture. Thanks to the Japan International Cooperation Agency (JICA) for financing the doctoral studies of the first author through the Program “Agriculture Studies Networks for Food Security (Agri-Net)”, to Tokyo University of Agriculture and Instituto Nacional de Investigaciones Agropecuarias (INIAP) for supporting this research. In addition, the authors thank the reviewers for their valuable contribution to improve the content of this scientific paper.
