Research Trends and Development Patterns in Microgreens Publications: A Bibliometric Study from 2004 to 2023

Abstract

This article presents a general overview of scientific publications in the field of microgreens using bibliometric tools. Data were collected from the Web of Science database (from Clarivate Analytics) in the period from 2004 to 2023, covering 20 years of scientific publications. The results are presented in the form of tables, graphs, and charts to analyze the development of microgreens publications. The countries with the greatest influence on the microgreens topic are the USA, Italy, and India, which have the highest number of publications in the analyzed period with 133, 76, and 38 publications, respectively. On the other hand, the authors with the highest number of publications are Raphael, Y. (University Naples Federico II-Italy), De Pascale, S. (University Naples Federico II-Italy), and Luo, Y. (ARS, Food Quality Laboratory, Environmental Microbial & Food Safety Lab, USDA-USA). The journals with the highest productivity in microgreens are HortScience (American Society of Horticultural Science), Horticulturae (MDPI), and Foods (MDPI), with publication numbers of 49, 27, and 23, respectively. Regarding the relationship of the documents in this study with United Nations Sustainable Development Goals (SDGs), the large majority of documents can be linked to SDG 2 (Zero Hunger), followed by SDG 13 (Climate Action) and SDG 3 (Good Health and Well Being). As a final remark, the mapping, trends, and findings in this work can help to establish logical paths for researchers in the field of microgreens.

1. Introduction

Microgreens is a relatively new term that originated in the United States in the 1980s and 1990s. At that time, some innovative chefs started using young plants in their restaurants to introduce new flavors, colors, and textures into various dishes [1,2]. These young plants were called microgreens and were used in a variety of culinary applications. Although the term “microgreens” first appeared in scientific literature only in the 2000s, they have gained popularity in recent years due to their unique taste and nutritional benefits [3,4]. Microgreens, although lacking a formal or regulatory definition, can be described as “immature plants” with the following distinguishing features, unlike sprouts: microgreens can be harvested for consumption within approximately 14 days, while certain species may require up to 21 days to reach harvest maturity [5]. Microgreens are characterized by the presence of completely expanded cotyledons or the first true leaf stage in plant growth [6]. This level of development places them between sprouts and baby vegetables or greens [7]. Their size varies between 5 and 10 cm long [8].

The production scale of microgreens is typically small and characterized by short distribution chains. This is because it is feasible to cultivate these crops in small domestic spaces, often utilizing vertical cultivation techniques to achieve a high density of plants.

Additionally, these crops can be grown close to their intended market, minimizing quality losses that may occur during handling, transportation, and distribution. In this respect, it is interesting to note that microgreens’ cultivation is carried out by restaurants, food banks, and also by individuals in their homes as a form of self-sufficiency [9,10]. It is also important to mention that the National Aeronautics and Space Administration (NASA) and other space agencies consider the production of microgreens as a viable alternative for food production in space missions [11,12,13].

In relation to the botanical families most commonly used for the cultivation and production of microgreens, we found the following families: Brassicaceae, Chenopodiaceae, Apiaceae, Amaranthaceae, Fabaceae, Lamiaceae, and Poaceae, covering an important number of genera and species [14]. In this sense, it is important to mention the use of plants of the Brasicaceae family as the most popular because of their simple cultivation and high content of beneficial compounds like polyphenols and glucosinolates [15].

An important point to highlight is their exceptional nutritional density, which makes them promising candidates in the context of functional foods [16], novel foods [17], and sources of essential oils for the cosmetic industry [16]. Since they are young plants, which will later give rise to their adult counterparts, there is a phenomenon of hyperconcentration of bioactive substances and phytochemicals, reaching several times the chemical composition of their mature counterparts [6,17]. This situation makes microgreens an ideal food for improving human health and preventing chronic, non-transmissible diseases such as cancer [18,19].

An interesting aspect to consider is the connection between microgreens and sustainability. Microgreens have fast growth cycles, can be grown efficiently in small spaces, and require fewer resources compared to traditional agriculture. Additionally, growing them in controlled environments like greenhouses or vertical farming systems reduces the need for pesticides and fertilizers [20]. These cultivation methods also allow for better water use, making microgreens’ cultivation a more sustainable practice [5].

On the contrary, a critical aspect to consider is the microbiological and food safety concerns associated with microgreens. Due to their nutrient-rich composition, high water activity, delicate physical nature, and consumption in a fresh state, there is a potential risk that they may contain foodborne pathogens. This poses a challenge to the microgreens industry and has prompted extensive investigations to ensure the safety of microgreens [21].

Finally, microgreens constitute a rapidly developing field of study that presents a range of exciting prospects in food security, nutrition, environmental sustainability, and the circular economy, among others [22,23]. Their potential contributions to these and other fields make them a commodity of considerable interest and an area of investigation for academics and business professionals alike.

For a better understanding of their utilization in different industries and potential future applications, bibliometric tools are of significant interest. Bibliometric tools have a crucial role in scientific research as they offer a systematic approach to assessing scientific output, research advancement, and impact in a particular field [24]. They are beneficial for measuring scientific impact through utilizing indicators and metrics, identifying trends and emerging areas of development, detecting collaboration patterns, and establishing strategies for publication and scientific collaboration [25].

The objective of this paper is to provide both novices and experts with an overview and visualization of the microgreens topic based on scientific publication data available in the Web of Science database for the period from 2004 to 2023.

2. Materials and Methods

Data on microgreens publications used for this article were extracted and downloaded between 8 January 2024 and 12 January 2024 from the Web of Science Core Collection (WoS) from Clarivate Analytics (www.webofscience.com, accessed on 8 January 2024). Web of Science is a widely used and highly respected database that provides researchers with access to a vast and diverse range of scientific literature. It offers an extensive collection of scholarly publications across all fields of science. Moreover, it possesses advanced search capabilities and a user-friendly interface; it allows researchers to easily search, filter, and download results to find relevant articles quickly [26,27].

The search was carried out using the following keywords: “Microgreens”; “Micro greens”; and “Micro-greens” in the field of search “topic” (which includes title, abstract, author keywords, and keywords plus), limiting the search between the years 2004 to 2023. After obtaining the search results, the chosen records were saved as plain text files (.txt), including both the complete record and the referenced citations for additional analysis. The process of bibliometric analysis is depicted in Figure 1.

The total number of records for the search yielded a total of 419 records, composed mainly of 338 research articles, 41 meeting abstracts, and 33 review articles. The complete distribution of all item types can be seen in Figure 2.

The data collected from WoS were classified and presented based on several bibliometric indicators, including the total number of publications (TP), total number of citations (TC), (H) Hirsch h-index, citation per year (C/Y), and citations per paper (C/P). Moreover, the free bibliometric research package VOSviewer 1.6.19 [28] was used to study graphical relationships such as co-authorship, co-occurrence, and co-citation. Additionally, R-Package Bibliometrix 4.1.4 [29] was used to analyze thematic relationships among other charts.

3. Results and Discussion

3.1. General Data Information

The results in this section are structured in three parts: the first contains general information about the dataset, the second contains information in the form of tables and rankings, and the third contains mappings of bibliometric relationships.

Figure 3 displays the distribution of publications across several categories in Web of Science; this allows us to visualize the scientific progress of the topic, to identify emerging areas, and to evaluate the distribution of knowledge about microgreens. The figure reveals that the categories with the greatest number of publications are on the edges, while the categories with the fewest publications are located in the center of the foam tree graph. The five groups with the highest number of publications are Food Science Technology (152), Horticulture (97), Plant Sciences (75), Agronomy (48), and Chemistry Applied (43) with 36.28%, 23.15%, 17.90%, 11.46%, and 10.26%, respectively. It is important to note that the publications on microgreens can be found in diverse fields ranging from applied engineering to materials science and pharmacology, to name but a few.

Since the year 2023, the WoS database has considered associations among sets of micro-citations and the 16 Sustainable Development Goals established in the United Nations Development Agenda 2030. In this way, it is possible to present a relationship demonstrating which of the 16 SDGs the publications indexed in WoS are contributing to. It is important to mention that the goal number 17 “Partnerships for the Goals” is not considered in the analysis.

Figure 4 below shows a foam tree containing the relationship between the scientific publications on the topic of microgreens and the SDGs. The figure shows that most of the publications are related to Sustainable Development Goal 2 “Zero Hunger” (39.8%) due to the relationship between microgreens and food sustainability; the h-index for publications in this SDG is 44 and the citation ratio per article is 25.51. The second SDG with the most publications is “Climate Action” with about 37% of the publications in the dataset, an h-index of 44, and 26.1 citations per article. Then comes SGD 3 “Good Health and Well Being” with a percentage close to 21%, h-index of 28, and 16.38 citations per article. The remaining four SDGs (Quality Education, Responsible Consumption and Production, Life Below Water, and Life on Land) present a low number of relationships with publications on microgreens.

With regard to the number of publications and citations during the period 2004–2023, Figure 5 illustrates the yearly output of scientific papers, revealing that publications on microgreens remained relatively low until 2017. Starting in 2018, there was a notable surge in publications, increasing from fewer than 10 papers annually to approximately 100 by the end of the observed period. In terms of citation counts, the data can be divided into three periods. The first period, from 2004 to 2012, saw minimal citation activity, culminating in a total of only four citations and three publications by 2012. The subsequent period up to 2016 experienced a modest rise in citations, reaching around 100 per year. From 2018 onwards, a more noticeable upswing in citation frequency occurred, exceeding 2300 citations and almost 100 publications in the most recent year recorded.

The most frequent words (in the field keyword plus) are quality, growth, and vegetables, with frequencies of 96, 73, and 51, respectively. Figure 6 illustrates a word cloud of the 50 most frequently used keywords and suggests the challenges, trends, and patterns in microgreens research for the studied period of time. The size of each keyword shows its frequency, and it can be noted that there are publications discussing issues related to growth parameters, plant metabolism, and chemical composition as main drivers.

Figure 7 presents a thematic map diagram considering the keyword plus field. The distribution of the words according to four categories with different degrees of development and relevance can be observed. Niche themes refer to specific, specialized topics within a broader field of study. These themes may not receive as much attention or as many citations as more mainstream topics but can still be important for advancing knowledge within a specialized area. In the niche themes quadrant, we can observe three clusters that contain the words Escherichia-coli O157:H7 (8) and Listeria monocytogenes (6); plant growth (11) and seedling (9); and fresh produce (11) and United States (7). This indicates that the most important niche topics are related to microbiology, agronomic, and commercial aspects. On the other hand, basic themes are fundamental topics or concepts that form the foundation of research within a field. These themes often represent core areas of inquiry that are widely studied and established within the literature. Within the quadrant representing the basic themes, there are two clearly identifiable clusters. The first cluster focuses on precise details of the many tactics employed to promote the growth of microgreens under varied conditions. The second cluster pertains to post-harvest considerations and the shelf-life of microgreens. Meanwhile, motor themes are core topics or concepts within a research field that are driving research activity and development. These themes often receive a high level of attention, generate a large volume of publications, and have a significant impact on the direction of research within a field. Within the motor and emerging/declining themes quadrants, there are no distinct clusters but rather overlapping ones. In the motor and basic quadrants, there are terms associated with bioactive compounds, including antioxidant activity (39), phenolic compounds (28), and bioactive compounds (22). Conversely, in the basic and emerging theme quadrants, there are terms related to safety, such as inactivation (9), microbial population (5), and survival (5).

To identify relationships between specific fields within the studied data, a Sankey diagram (Figure 8) was elaborated, considering relationships between countries of origin of the publications (left), author (middle), and keywords (right). In the graph, the importance of countries such as Italy, the USA, and Cyprus can be seen from the respective list of authors, and the most preferred keywords by the authors are also visible, such as carotenoids, microgreens, and functional foods.

Finally, to complete the general information of the studied data, a thematic evolution is presented in Figure 9, considering three periods (2004–2014, 2015–2020, and 2021–2023). In the first period, rather basic topics related to ascorbic acid content, growth, and lettuce were the most important topics in the first publications on microgreens. In the following period (2015–2020), a diversification of the published topics was observed, highlighting topics on quality attributes and chemical composition. Lastly, in the most recent period (2021–2023), quality aspects were maintained, and topics related to microbiology and the cultivation of microgreens using different types of lighting to enhance growth can also be seen.

3.2. Tables and Rankings

To provide a more detailed insight,

Table 1. Top 20 articles on microgreens between 2004 and 2023.

R	TC	Title	Authors	Type	Ref.	C/Y
1	243	Assessment of Vitamin and Carotenoid Concentrations of Emerging Food Products: Edible Microgreens	Xiao, Z.; Lester, G.; Luo, Y.; Wang, Q.	a	[14]	18.69
2	213	Micro-scale vegetable production and the rise of microgreens	Kyriacou, M.; Rouphael, Y.; Di Gioia, F.; Kyratzis, A.; Serio, F.; Renna, M.; De Pascale, S.; Santamaria, P.	r	[30]	23.67
3	178	Increases in Shoot Tissue Pigments, Glucosinolates, and Mineral Elements in Sprouting Broccoli after Exposure to Short-duration Blue Light from Light Emitting Diodes	Kopsell, D.; Sams, C.	a	[31]	14.83
4	120	Blue and Red LED Illumination Improves Growth and Bioactive Compounds Contents in Acyanic and Cyanic Ocimum basilicum L. Microgreens	Lobiuc, A.; Vasilache, V.; Pintilie, O.; Stoleru, T.; Burducea, M.; Oroian, M.; Zamfirache, M.	a	[32]	15
5	110	Functional quality in novel food sources: Genotypic variation in the nutritive and phytochemical composition of thirteen microgreens species	Kyriacou, M.; El-Nakhel, C.; Graziani, G.; Pannico, A.; Soteriou, G.; Giordano, M.; Ritieni, A.; De Pascale, S.; Rouphael, Y.	a	[33]	18.33
6	108	The effects of LED illumination spectra and intensity on carotenoid content in Brassicaceae microgreens	Brazaityte, A.; Sakalauskiene, S.; Samuoliene, G.; Jankauskiene, J.; Virsile, A.; Novickovas, A.; Sirtautas, R.; Miliauskiene, J.; Vastakaite, V.; Dabasinskas, L.; Duchovskis, P.	a	[34]	10.8
7	104	Profiling Polyphenols in Five Brassica Species Microgreens by UHPLC-PDA-ESI/HRMSn	Sun, J.; Xiao, Z.; Lin, L.; Lester, G.; Wang, Q.; Harnly, J.; Chen, P.	a	[35]	8.67
8	103	LED irradiance level affects growth and nutritional quality of Brassica microgreens	Samuoliene, G.; Brazaityte, A.; Jankauskiene, J.; Virsile, A.; Sirtautas, R.; Novickovas, A.; Sakalauskiene, S.; Sakalauskaite, J.; Duchovskis, P.	a	[36]	8.58
9	96	Comparison between the mineral profile and nitrate content of microgreens and mature lettuces	Pinto, E.; Almeida, A..; Aguiar, A.; Ferreira, I.	a	[37]	9.6
10	93	Sprouting Broccoli Accumulate Higher Concentrations of Nutritionally Important Metabolites under Narrow-band Light-emitting Diode Lighting	Kopsell, D.; Sams, C..; Barickman, T.; Morrow, R.	a	[38]	8.45
11	90	The Science behind Microgreens as an Exciting New Food for the 21st Century	Choe, U.; Yu, L.; Wang, T.	r	[39]	12.86
12	90	Blue light dosage affects carotenoids and tocopherols in microgreens	Samuoliene, G.; Virsile, A.; Brazaityte, A.; Jankauskiene, J.; Sakalauskiene, S.; Vastakaite, V.; Novickovas, A.; Viskeliene, A.; Sasnauskas, A.; Duchovskis, P.	a	[40]	11.25
13	90	Microgreens: Production, shelf life, and bioactive components	Mir, S.; Shah, M.; Mir, M.	r	[41]	11.25
14	89	A review on the effects of light-emitting diode (LED) light on the nutrients of sprouts and microgreens	Zhang, X.; Bian, Z.; Yuan, X.; Chen, X.; Lu, C.	r	[42]	17.8
15	80	Current Review of the Modulatory Effects of LED Lights on Photosynthesis of Secondary Metabolites and Future Perspectives of Microgreen Vegetables	Alrifai, O.; Hao, X.; Marcone, M.; Tsao, R.	r	[43]	13.33
16	80	Microgreens of Brassicaceae: Mineral composition and content of 30 varieties	Xiao, Z.; Codling, E.; Luo, Y.; Nou, X.; Lester, G..; Wang, Q.	a	[44]	8.89
17	78	Microgreen nutrition, food safety, and shelf life: A review	Turner, E.; Luo, Y.; Buchanan, R.	r	[21]	15.6
18	73	Growth of Impatiens, Petunia, Salvia, and Tomato Seedlings under Blue, Green, and Red Light-emitting Diodes	Wollaeger, H.; Runkle, E.	a	[45]	6.64
19	72	Sprouts and Microgreens: Trends, Opportunities, and Horizons for Novel Research	Galieni, A.; Falcinelli, B.; Stagnari, F.; Datti, A.; Benincasa, P.	r	[46]	14.4
20	70	Evaluation and correlation of sensory attributes and chemical compositions of emerging fresh produce: Microgreens	Xiao, Z.; Lester, G.; Park, E.; Saftner, R.; Luo, Y.; Wang, Q.	a	[47]	7

R = ranking; TC = total citations; a = article; r = review; Ref. = reference; C/Y = citations per year.

was constructed using the Web of Science database, listing the 20 most cited articles between 2004 and 2023. This information may help the reader who is just becoming familiar with the subject as a guide for selecting relevant literature. The table shows that most of them are research articles (65%), followed by review articles (35%). The article with the highest frequency of citations, with 243 citations, is an original research work that considers the nutritional content of microgreens and their potential health benefits, as well as the need for further research and data on the phytonutrient content of these emerging food products, among others. This article, written by authors Xiao, Z.; Lester, G.; Luo, Y.; and Wang, Q. [14], was published in the Journal of Agricultural and Food Chemistry in 2012 with a total of 18.69 citations per year. The second most cited article has 213 citations and discusses factors affecting the production and quality of microgreens, such as species selection, fertilization, and lighting. It also focuses on the challenges facing microgreens production and highlights areas that need further research. In summary, the article explores the potential of microgreens to improve the nutritional quality of the human diet and how they can be produced effectively and sustainably; this article was published in Trends in Food Science & Technology in 2016 by authors Kyriacou, M.; Rouphael, Y.; Di Gioia, F.; Kyratzis, A.; Serio, F.; Renna, M.; De Pascale, S.; and Santamaria, P. [30], with 23.67 citations per year. Finally, the article that ranks third among the most cited articles reaches a number of 178 citations during the period 2004–2023 and it focuses on giving a perspective on the significant impact of short-duration blue light exposure on the nutritional quality and phytochemical composition of sprouting broccoli microgreens, highlighting the potential benefits for human health and the value to consumers; its authors are Kopsell, D., and Sams, C. [31], it was published in the Journal of the American Society for Horticultural Science in 2013, and it presents 14.83 citations per year.

In order to study the situation of the authors with the highest productivity and influence during the period 2024–2023,

Table 2. Top 20 authors in microgreens between 2004 and 2023.

R	Author Name	Organization	Country	TP	TC	H	C/P
1	Rouphael, Y.	Univ Naples Federico II	Italy	23	732	12	31.83
2	De Pascale, S.	Univ Naples Federico II	Italy	22	707	12	32.14
3	Luo, Y.	ARS, Food Qual Lab, Environm Microbial & Food Safety Lab, USDA	USA	21	939	14	44.71
4	Kyriacou, M.	Agr Res Inst	Cyprus	20	722	12	36.10
5	El-Nakhel, C.	Univ Naples Federico II	Italy	19	441	11	23.21
6	Graziani, G.	Univ Naples Federico II	Italy	15	397	10	26.47
7	Xiao, Z.	Johnson & Wales Univ	USA	15	883	12	58.87
8	Santamaria, P.	Univ Bari Aldo Moro	Italy	15	453	8	30.20
9	Pannico, A.	Univ Naples Federico II	Italy	14	375	9	26.79
10	Zheng, Y.	Univ Guelph	Canada	14	236	10	16.86
11	Wang, Q.	Univ Maryland	USA	14	848	12	60.57
12	Sams, C.	Univ Tennessee	USA	13	354	5	27.23
13	Ritieni, A.	Univ Naples Federico II	Italy	13	380	10	29.23
14	Samuoliene, G.	Lithuanian Res Ctr Agr & Forestry	Lithuania	12	507	8	42.25
15	Di Gioia, F.	Penn State Univ	USA	12	333	4	27.75
16	Kong, Y.	Univ Guelph,	Canada	12	154	7	12.83
17	Brazaityte, A.	Lithuanian Res Ctr Agr & Forestry	Lithuania	11	536	9	48.73
18	Kopsell, D.	Univ Florida	USA	11	393	5	35.73
19	Renna, M.	Univ Bari Aldo Moro	Italy	11	414	9	37.64
20	Yang, T.	ARS	USA	10	282	7	28.20

R = ranking; TC = total citations; TP = total publications; H = h-index; C/P = citations per publication.

was constructed, which considers a ranking of the authors with the highest number of publications, number of citations, citations/article in the period, h-index, affiliation, and country. This information allows for the identification of subject matter experts, facilitates networking and collaboration, and guides future research. The author Rouphael, Y., with an affiliation to the University Naples Federico II-Italy, was the most productive author regarding microgreens publications between 2004 and 2023 with 23 published articles, which have a number of 732 citations in the period and an h-index of 12. The second author with most publications in the dataset studied was De Pascale, S., with an affiliation to the same research group as above, 22 publications, 707 citations, and an h-index of 12. The author with the highest h-index and total number of citations (14 and 939, respectively) corresponds to Luo, Y., belonging to ARS, Food Qual Lab, Environmental Microbial & Food Safety Lab, USDA, with 21 publications for the period under study, ranking third in the table. The table also highlights the author Wang, Q., who belongs to the University of Maryland, with the highest metric in terms of citation per article ratio, reaching 60.57, and who is ranked number 11. It is also worth noting that the author in the 17th position, Brazaityte, A., stands out for having a high citation per article ratio, which is 48.73.

Regarding the countries with the highest contribution between 2004 and 2023 for the keywords in this study (microgreens, micro-greens, and micro greens),

Table 3. Most influential countries in microgreens publications between 2004 and 2023.

R	Country	TP	TC	H	C/P
1	USA	133	2717	31	20.43
2	Italy	76	1557	22	20.49
3	India	38	344	9	9.05
4	China	33	554	12	16.79
5	Canada	24	372	12	15.50
6	Cyprus	22	723	12	32.86
7	Spain	16	303	10	18.94
8	South Korea	15	180	6	12.00
9	Lithuania	14	567	10	40.50
10	Thailand	14	106	6	7.57

R = ranking; TC = total citations; TP = total publications; H = h-index; C/P = citations per publication.

shows a ranking considering total publications, total citations, h-index, and citations per paper. This information can identify the presence of centers of excellence and leadership in a topic, provide a more complete understanding of the geographic distribution, and can be helpful in establishing collaboration policies and allocating resources to promote priority areas.

The USA, Italy, and India were the most influential countries, concentrating almost 65% of the total number of published papers among the 10 most productive countries. The USA is the country with the highest number of publications (133), the highest h-index (31), and also with the highest amount of citations (2717), but the highest number of citations per paper belongs to Lithuania with 40.50, ranked number 9 in the list.

In order to evaluate what are the most productive and influential journals,

Table 4. Most influential and productive journals in microgreens between 2004 and 2023.

R	Journal Name	Publisher	TP	TC	C/P	IF	Q	H
1	Hortscience	Amer Soc Horticultural Science	49	301	6.14	1.9	2	10
2	Horticulturae	MDPI	27	205	7.59	3.1	1	8
3	Foods	MDPI	23	349	15.17	5.2	1	12
4	Agronomy-Basel	MDPI	21	343	16.33	3.7	1	10
5	Frontiers in Plant Science	Frontiers Media Sa	16	226	14.13	5.6	1	7
6	Plants-Basel	MDPI	15	183	12.20	4.5	1	6
7	Journal of Agricultural and Food Chemistry	Amer Chemical Soc	10	712	71.20	6.1	1	9
8	Antioxidants	MDPI	9	182	20.22	7	1	6
9	Molecules	MDPI	8	244	30.50	4.6	2	7
10	Journal of the Science of Food and Agriculture	Wiley	7	192	27.43	4.1	1	6
11	Scientia Horticulturae	Elsevier	6	146	24.33	4.3	1	4
12	Food Control	Elsevier Sci Ltd.	6	37	6.17	6	1	4
13	Journal of Food Composition and Analysis	Academic Press Inc Elsevier Science	6	266	44.33	4.3	2	4
14	Agriculture-Basel	MDPI	6	21	3.50	3.6	1	2
15	Postharvest Biology and Technology	Elsevier	6	192	32.00	7	1	4
16	Food Research International	Elsevier	5	72	14.40	8.1	1	5
17	Journal of Food Processing and Preservation	Wiley	4	20	5.00	2.5	3	3
18	Journal of Agriculture and Food Research	Elsevier	4	38	9.50	3.8	1	1
19	LWT-Food Science and Technology	Elsevier	4	165	41.25	6	1	3
20	ACS Food Science & Technology	Amer Chemical Soc	3	24	8	2.3	3	3

R = ranking; TP = total publications; TC = total citations; C/P = citations per publication; IF = impact factor; Q = quartile; H = h-index.

was constructed, considering publisher, total publications, total citations, citations per article, the impact factor of the journal, in which quartile it is located, and the h-index for the period 2004–2023 for microgreens publications.

The journal that has published the highest number of documents on microgreens is Hortscience, a specialized journal that publishes research in the field of applied horticultural research derived from high-value specialty crops and their components or products with 49 publications. On the other hand, the journal with the highest number of citations in the period (712 citations) is the Journal of Agricultural and Food Chemistry, ranked 7th in the list, which also has the highest citation per article ratio (71.20). The journal with the highest h-index, corresponding to 12, is the journal published by MDPI, Foods. It should be noted that the journal with the highest impact index in the ranking (8.1) is the 16th ranked journal, Food Research International, which makes it one of the best options for publishing scientific articles in the field of microgreens. It is also observed that most of the journals (75%) are in quartile 1 within their respective category.

In order to analyze the distribution of the different funding sources for publications on microgreens between 2004 and 2023,

Table 5. Top funding sources in microgreens publications between 2004 and 2023.

R	Funding Agency	Country	TP	TC	H
1	United States Department of Agriculture	USA	30	981	11
2	Natural Sciences and Engineering Research Council of Canada	Canada	13	213	9
3	National Natural Science Foundation of China	China	11	103	6
4	USDA Agricultural Research Service	USA	11	609	7
5	CGIAR	-	11	204	9
6	Research Council of Lithuania	Lithuania	10	533	9
7	Greenbelt Microgreens Ltd.	Canada	10	171	7
8	European Union EU	-	9	236	7
9	Agenzia Spaziale Italiana	Italy	9	181	4
10	Autonomous Community of the Region of Murcia	Spain	5	57	3

R = ranking; TP = total publications; TC = total citations; H = h-index.

was constructed containing a list of funding agencies, countries, total publications, total citations, and h-index. In first place is the United States Department of Agriculture-USDA with 30 publications, the largest number of citations (981), and the highest h-index (11) for the period under study. In second place is the agency Natural Sciences and Engineering Research Council of Canada with 13 publications and in third place is the National Natural Science Foundation of China. On the other hand, the presence of the funding agencies CGIAR and the European Community is striking, in fifth and eighth place, respectively. Finally, in 11th place (not shown in the table) is Open Philanthropy through the grant Food Resilience in the Face of Catastrophic Global Events.

3.3. Mapping Relationships

Regarding co-authorship relationships, the country with the highest total link strength is Italy, followed by the USA and Cyprus (36, 32, and 22, respectively) (Figure 10). It is also interesting to note that Figure 10 complements the information in Table 3. This graph indicates the direction and magnitude of collaborations between the different countries and how they contribute to the intellectual development of scientific papers. The figure shows nine clusters containing the 49 countries that are related through joint papers. Furthermore, there are 15 countries where co-authorship relationships are not present and are therefore not shown in the graph.

Figure 11 presents the co-occurrence relationship considering the keyword plus field. Co-occurrence refers to the simultaneous presence or appearance of certain elements, such as keywords, terms, or concepts, within the same document, article, or body of literature. Co-occurrence analysis is a quantitative method used to identify and analyze the relationships between these elements based on their appearance together in the same context. In Figure 11, we can see nine clusters with different colors; the items quality (142; 91), growth (135; 72), and vegetables (115; 51) are all in the same cluster and present the highest metrics (links and total link strength, respectively). It can also be seen that in the lower right part of the same figure, there is a time scale that goes from 2019 to 2022, which also allows for the identification of a temporal relationship between the different items; the yellow ones are the most recent ones, and on the other hand, the blue ones are topics with older publication dates.

In relation to the influence and importance of different institutions in the microgreens topic, Figure 12 presents the citation ratio by organizations in the form of a heat map. The first is the University of Maryland (143 links, 1361 total link strength, and 23 documents), followed by the University of Naples Federico II (124 links, 1352 total link strength, and 28 documents), and in third place in terms of link strength (1321) is ARS with 138 links and 23 documents.

The co-citation relationship occurs when two or more documents, like articles, papers, or books, are often cited simultaneously by other documents. This relationship highlights a link between the documents that are cited together, showing they are regarded as related or have an impact in the academic community.

Figure 13 contains a distribution of 198 authors and their co-citation networks. The most important is the author Xiao, Z., with 197 links, 482 citations, and a total link strength of 433.58. The second most important author is Kyriacou, M., with 370 citations, 197 links, and a total link strength of 345.82. Finally, Samouliene, G., presents a total link strength of 199.82, 211 citations, and 196 links.

4. Conclusions

A bibliometric analysis of the articles published on the subject of microgreens has been presented, and it can be concluded that the main areas of research are in the fields of Food Science Technology, Horticulture, and Plant Sciences. With regard to the development of the topic, a significant increase in publications can be observed from 2017 onward, which was maintained in a sustained manner until the end of the period analyzed. This trend makes it possible to visualize the importance of microgreens research and to predict its growth in the coming years.

With regard to the most influential countries and institutions, the USA, Italy, and India are the highest ranked, and with regard to the most influential authors, Rouphael, Y., De Pascale, S., and Luo, Y., are the highest ranked and most productive.

On the other hand, the various bibliometric tools used allow for the establishment of critical routes and provide useful information for researchers interested in the field of microgreens. As demonstrated throughout the work, the subject of microgreens is a field with an important growth and with applications in various fields related to food science and nutrition, among other fields.

In terms of the practical applications of this work and its usefulness for decision-making on issues such as the development of new research, search for international collaboration, and promotion of knowledge, it is also possible to visualize gaps and opportunities for innovation. In terms of future research, this work could guide the exploration of cultivation methods, studies of nutritional benefits, economic feasibility, and market analysis, environmental impact assessments, and sustainability in microgreens production at different scales.

Finally, it is important to mention that this work, based on a bibliometric approach, presents only publications indexed in the WoS database, leaving aside works published in journals not indexed in WoS, as well as other documents such as technical reports, websites, and other types of publications that could contain important information on microgreens.