Analysis of collaboration networks for scientific and technological research on passion Fruit

: Scientific research on passion fruit has been conducted in several institutions worldwide, and it is of interest to the productive sector, the scientific community, and science and technology managers to learn about current scientific advances and opportunities through metric studies of bibliographic information. A survey of publications indexed in the Web of Science and the Agricultural Research Database— BDPA, in European Patent Office – Espacenet, and Embrapa’s technologies and projects were used as indicators to characterize research networks. This study analyzed the co-authorship and co-citation network of scientific production, the strength of connections among institutions, and a map of co-occurrence of keywords from 2001 to 2020. Brazil, the United States, Colombia, and France had the largest co-authorship networks for Passifloraceae. Brazilian institutions that are in a prominent position in the analysis of co-authorship networks and that produced the largest number of publications were Embrapa, University of São Paulo (USP), and State University of Campinas (Unicamp). The main themes studied were adsorption, antioxidant, clarification, evolution, flavonoid, flowering, growth, and somatic embryogenesis. Patents related to the use of passifloras were highest between 2015 and 2017 and were mainly focused on the production of food, beverages, cosmetics, and medicines. Brazil has relevant bibliographic production and technological development regarding passion fruit for the academic community and rural producers. These results integrated aspects of scientific activity that can help explore new research directions and explain the use and circulation of scientific production.


INTRODUCTION
The importance of passion fruit (Passiflora L.) in agribusiness is growing worldwide.Passion fruit is a plant native to Brazil and is generally marketed for fresh consumption or the pulp industry.Premium-quality fruits have a relatively high market value (GOMES et al. 2006, FALEIRO, 2022).Genetic improvement and passion fruit-related technologies developed in recent decades have contributed to the understanding and expansion of its cultivation in Brazil and worldwide (FALEIRO et al. 2020).According to data from the Food and Agricultural Organization (FAO) of the United Nations (2018), world passion fruit production was estimated at 1.5 million tons/year, approximately 65% of which was grown in Brazil.In 2020, Brazilian production reached 690,000 tons (IBGE, 2021).Colombia, Indonesia, Peru, Ecuador, Australia, and New Zealand are also important producers and exporters of the fruit.

Scientific research on passion fruit has
been conducted in several institutions worldwide.Parameters such as co-citation analysis, coauthorship, and number of patents demonstrate links and a scientific collaboration network through the link strengths of existing parameters and relationships (ZUPIC & CATER, 2015).These variables affect the complementarity among innovation activities from internal and external perspectives and are used as scientific and technological policies by several governments to encourage the formation of new scientific networks and links among countries, institutions, and researchers as well as to find out the impacts of the main programs in these organizations (KIDD, 1990).
CASSIMAN & VEUGELERS (2006) identified the dependence on basic research and importance of universities and research institutions as sources of information for the innovation process.Bibliometric historical analyses portray advances in research and provide a perspective of science networks.Therefore, these analyses are considered important tools for the scientific community in different thematic areas and serve as an introduction for those interested in knowing the trends, histories, subjects, and geographical distribution of specific themes (MACIAS-CHAPULA, 1998, CARUSO & TIGRE, 2004).The technological prospection of patents in international databases is useful for the development of new technologies.It includes recent performance analyses of the sector, the perception regarding companies' investment capacity, and the identification of technological trajectories that help clarify important market issues to guide new opportunities for research projects and prospect the continuity of growth (CARUSO & TIGRE, 2004).
This research analyzed scientometric indicators on the theme of Passiflora, based on the parameters of technical-scientific and technological collaboration among authors and educational and research institutions worldwide.

MATERIALS AND METHODS
To analyze co-citation and co-authorship, we used the Web of Science (WoS) database, with the main collection taking place on June 23, 2021.The research networks on passion fruit were mapped by educational and research institution, country, year of publication, and study themes.These data were used to construct measures of similarity and influence, generate structural images of scientific fields, and identify interconnection networks.The search terms and expressions used were "passion fruit", "passion-fruit", "passiflora" and "maracujá" (Portuguese for passion fruit).Due to orthographic variations in the abbreviation of authors' names and abbreviations and acronyms of educational and research institutions, the database was standardized to ensure accuracy in the generation of bibliometric indicators (GLÄNZEL, 2003).The publications cited in WoS and the Embrapa Agricultural Research Database (BDPA) and Embrapa's technological production were analyzed for four periods: P1 (2001-2005), P2 (2006-2010), P3 (2011-2015), and P4 (2016-2020).
Embrapa's bibliographic production data were extracted from the BDPA on June 10, 2021, and its technological production was extracted from the Asset Management System (EMBRAPA, 2021) on June 25, 2021.Technological monitoring of the expression "passion fruit OR passiflora" was carried out in the database maintained by the European Patent Office (Espacenet) on July 2, 2021.
The bibliometric statistical analysis was based on ZUPIC & CATER (2015) and VAN ECK & WALTMAN (2017) using VosViewer software version 1.6.18.Link strength is a measure of similarity represented by lines and spheres in bibliometric maps or by positive numerical values, which ranged from 0 to 107 in this study.
The sphere size represents the link strength between the co-authoring or co-occurring indicators.The thickness of the lines between the spheres illustrates the connection between the indicators; the thinner the lines and the smaller the spheres, the lesser the link strength, and the thicker the lines and the larger the spheres, the more relevance and proximity the items have.Clusters of spheres are represented by colors and positioned by similarity.
For the analyses of co-authorship and cooccurrence, the following criteria were established to generate the bibliometric maps: for co-authorship between institutions, at least 5 publications from the same educational and research institutions and 5 joint publications between institutions in the period; for co-authoring between countries, at least 10 publications in the same country in the period; and for keyword co-occurrence, at least 10 occurrences in the period.
For the co-citation analysis, the minimum criterion of occurrence was 10 citations per article, the same academic scoring system used to include articles in the calculation of Google's metric and time tracking (GOOGLE, 2011).

RESULTS AND DISCUSSION
The WoS database contained 40 papers published between the late 1940s and the 1970s, which addressed chemical, medicinal, agricultural, and food aspects of the Passifloraceae family.The total number of publications analyzed in this paper between 2001 and 2020 was 2,859.In the period from 2001 to 2005 (P1), 278 documents were published.This number doubled over the next five years, totaling 541 documents in P2.The number of publications increased over the years, reaching 864 and 1,176 in P3 and P4, respectively.This increase suggests that there was a need to fill gaps in knowledge regarding the cultivation of this crop, which has a privileged market position in fruit growing, with a view to providing an alternative that will diversity production systems, and also for its use as a functional, ornamental, and medicinal food.
The co-citation analysis of P1 and P2 showed a predominance of phytotherapeutic and pharmacological themes.Table 1 shows that in descending order, DHAWAN et al. ( 2004 Table 2 shows the number of publications in WoS and the link strength of the 20 main educational and research institutions on passion fruit.The link strength ranged between 2 and 5 in P1, 15 and 55in P2, 22 and 111in P3, and 27and 107in P4.In P1, USP, Embrapa, and UFRGS published 18, 14, and 11 articles, respectively.Moreover, the USP and Embrapa had the highest link strengths in this period. In P2, Embrapa was the institution with the highest link strength, followed by Unicamp, UnB, USP, and UFRGS with 49, 32, 26, 45, and 34 publications, respectively.In P3, Embrapa continued to be the institution with the highest link strength, followed by Unicamp, UFV, and USP, with a total of 240 publications.In P4, Embrapa remained the institution with the highest link strength, followed by USP, UFRB, UFV, and UNESP, which together published 272 documents.UFRB, founded in 2005, is located in the Brazilian state of Bahia, which is a major center for passion fruit production, and in P4, this institution had the third highest link strength and fifth highest number of publications.The strategy adopted by Embrapa for the development of research projects in partnership with graduate programs may explain the increase in link strength and passion fruit collaboration networks.The predominance of Brazilian institutions is consistent with the privileged market position of this crop in the country; passion fruit has a well-established marketing chain and a well-organized industrial sector with a good supply chain (FERNANDES et al., 2019).
From 2006, 2010, and 2016 onward, bibliographic production on Passiflora cited in WoS increased (Figure 1).Event sheld in Latin America, such as the IV Reunião Técnica de Pesquisas em Maracujazeiro (IV Technical Meeting for Research on    - was the launch of the world's first hybrid sour passion fruit cultivars in 2008 (EMBRAPA, 2008).
The number of technical publications in WoS increased alongside the number of patent applications, thereby suggesting that there was high technological demand in the 20 years (Figure 1).A total of 2,649 patent applications were filed with the World Intellectual Property Organization and 1,588 with the European Patent Office.These indicators showed the interest of the international market in the genus Passiflora as a raw material for food, beverages, cosmetics, and medicines.Most of the demand came from the United States and Germany.The highest numbers of patent applications were in 2015, 2016, and 2017 at1,916, 2,064, and 1,980, respectively.
The co-authorship analysis for the 2001-2020 period showed 105 countries composing the passion fruit thematic network, but of these, only 41 had over 10 publications in the period.Data that met the analysis criterion were grouped into seven clusters, with the majority of the publications coming from Brazil, the United States, Colombia, India, and France, with 1,587, 242, 144, 124, and 105 publications, respectively (Figure 2).
In P1, P2, P3, and P4, there were 256, 494, 753, and 1,261 institutions with publications in the network, respectively.Figure 3 shows the bibliometric maps of the evolution of the co-authorship network in the four periods considering the criterion established in the research.The networks formed in each period were composed of 15, 29, 54, and 82 institutions forming 2, 6, 9, and 9 clusters, respectively.
From 2001 to 2020, the interest in conducting research in the area of passifloras was evident, with the number of institutions that published together increasing five-fold.The production of knowledge and common technologies among institutions favored the formation of research arrangements and information flows for the production sector (PENTEADO FILHO et al., 2017).
The network of co-occurrence of keywords during 2001-2020 is shown in figure 4.There was a higher number of publications on biological and pharmacological aspects with flavonoids and antioxidant properties, especially in Brazil, the United States, and Colombia.The different species of Passifloracea are potential sources of molecules of pharmacological relevance and several other active components contained in the pulp, leaves, bark, and seeds (DHAWAN et al., 2001(DHAWAN et al., , 2004;;ZERAIK et al., 2010).Works on aspects related to agricultural cultivation on growth and flowering, in which Brazilian authors were prominent, had greater link strength.These categories of subjects, related to production, were the most studied in the country, which is the main producer and consumer of the fruit (FAO, 2018).The most evident terms in the nine clusters formed on the map were adsorption, antioxidant, clarification,  In terms of the number of publications on passion fruit, the main institution was Embrapa, for which the number of publications on WoS increased over the first three periods studied (P1, P2, and P3) and remained the same in P4 (Figure 5).Regarding the perspective of  bibliographic production aimed at serving the production sector, the institution had 1,890 technical publications in the Agricultural Research Database (BDPA, 2021).This database followed the same pattern of a significant increase in publications between P1 and P2, with the number of publications remaining the same from P3 to P4.These bibliographic productions identified problems and demands related to rural producers focused on productive activity.In this context, there is a strengthening of ties between public research institutions and technology transfer and the productive sector, thereby filling gaps in knowledge on how to optimize rural producers' performance in the production chain.
Ciência Rural, v.54, n.1, 2024.Between 2001 and 2020, Embrapa conducted 178 research projects and developed 51 production-related technologies; 11 ornamental, wild, sweet, and sour passion fruit cultivars; 16 agricultural practices; and 11 processes for food production (EMBRAPA, 2021a, EMBRAPA, 2021b).Most of these technological solutions were developed through partnerships with universities, state research entities, technical assistance companies, and the productive sector.The adoption of these technologies and their impacts on the passion fruit production system are routinely evaluated in the Embrapa research centers through a reference methodology described by AVILA et al. (2008).These evaluations include cultivars launched in 2008 that generated about 5,000 direct jobs, over 10,000 indirect jobs, and 400 million Brazilian reals on the wholesale market in 2016 (EMBRAPA, 2016).Besides improving crop production, the cultivars have benefited companies and research institutions, which have used the genetic material as the basis for several scientific and technological studies (EMBRAPA, 2022).
Understanding the technical-scientific collaboration network complements the sources of information for academics, managers, and public policy policymakers.This combination of indicators contributes to the implementation of research, development, and technology transfer strategies.Additionally, this information demonstrates the progress of the theme and contributions of the implementation and dissemination of knowledge for the production sector, bearing in mind the importance of joint efforts among the different stakeholders.

CONCLUSION
The study results show an increase in the production of technical and scientific publications on the genus Passiflora worldwide.Embrapa, USP, UFV, Unicamp, and UNESP were the educational and research institutions that published the most research between 2001 and 2020 worldwide.
In all the studied databases, the largest number of publications was from authors associated with Brazilian educational and research institutions.Embrapa was the institution with the highest number of publications in WoS and the strongest link strength across all four periods evaluated.
The number of downloads of technical publications aimed at rural producers, the number of research projects, and the number of technological solutions developed reinforce Embrapa's role in the generation and transfer of technology on the family Passifloraceae.Patents filed worldwide show trends and opportunities in the food, beverage, cosmetics, and medicine markets.
The information presented in this study is a source of knowledge for understanding the growth of production, research, and technologies related to passion fruit.The results showed the relationship between increased agricultural production and the time series of the development of the research network worldwide.
), SOULIMANI et al. (1997), and DHAWAN et al. (2001) had the highest number of citations.In P3, the most cited articles were those by DHAWAN et al. (2004), MUSCHNER et al. (2003), ULMER & MACDOUGAL (2004), and YOCKTENG & NADOT (2004) and were related to plant botany, biogeography, and phylogeny.In P4, the most cited articles were those of DHAWAN et al. (2004), ULMER & MACDOUGAL (2004), and FEUILLET and MACDOUGAL (2003) in relation to the classification of the Passifloraceae family.DHAWAN et al. (2004) described the morphological aspects and traditional, pharmacological, and toxicological uses of species of the genus Passsiflora.Due to the scope of discussion of this article, this study has been significantly used by the scientific community, with an average of 400 citations per year.

Figure 1 -
Figure 1 -Evolution of publications in WoS and evolution of patent deposits in the period 2001-2020.

Figure 2 -
Figure 2 -Bibliometric map of co-authorship networks in the countries in the period 2001-2020.The size of the circles and the thickness of the lines indicate the greatest expression of the indicators.Colors indicate clusters among research teams.
Turazi et al. evolution, flavonoid, flowering, growth, and somatic embryogenesis.This diversity and interdisciplinarity of terms demonstrate that the scientific basis of Passifloracea has been extensively researched in Brazil and worldwide.

Figure 3 -
Figure 3 -Bibliometric maps of evolution of the co-authorship network of WoS publications by teaching and research institution in four periods (P1, P2, P3 and P4).The size of the circles and the thickness of the lines indicate the greatest expression of the indicators.Colors indicate clusters among research teams.

Figure 4 -
Figure 4 -Bibliometric map of co-occurrence of keywords in the period from 2001 to 2020.The size of the circles and the thickness of the lines indicate the greatest expression of the indicators.Colors indicate clusters among research teams.

Figure 5 -
Figure 5 -Embrapa publications on WoS, on BDPA and technologies developed by Embrapa, related to passion fruit culture, grouped into four periods.

Table 2 -
Number of publications in WoS and link strength of the first twenty institutions of education and research on Passiflora grouped into four periods between 2001 and 2020.

Table 3 -
Technical publications and number of downloads from 2001 to 2020 related to passion fruit culture in the Agricultural Research Database.