Ketupat: a culinary heritage of Indonesia in Eid Al-Fitr tradition

Abstract

Indonesia is renowned for its cultural diversity and traditions, which are closely related to religious practices. Among these, the kupatan tradition, a significant Muslim custom, symbolizes gratitude and is prominently observed during major Islamic celebrations, such as Eid Al-Fitr. Ketupat is a typical culinary heritage of this tradition. It is a rice-based dish wrapped in diamond-shaped of young coconut leaves (janur), reflecting a deep cultural and religious connection. This review explores the cultural significance of ketupat from socio-cultural and philosophical perspectives, as well as its cooking methods, physicochemical transformation, shelf-life, and safety aspects. It also addresses the challenges and future prospects for ketupat, including the difficulty of integrating modern technology without losing its cultural essence and the specialized skills required for crafting janur containers. The review suggests that focusing on sustainable production practices, product innovation, efficient processing methods, and effective promotion and marketing strategies could significantly enhance the future outlook for ketupat. This study will provide a crucial basis for future research on ketupat, emphasizing its long-term food value.

Introduction

Indonesia is a nation characterized by its remarkable diversity in tribes, languages, traditions, and religions. The archipelago comprises over 17,000 islands, extending from Papua in the east to Sumatera in the west. This extensive territory hosts approximately 1300 ethnic groups and more than 700 languages, reflecting the nation's rich cultural heritage. The national motto, Bhinneka Tunggal Ika, which translates to unity in diversity, represents the fundamental principle of Indonesian identity [1]. Culture, or “budaya” in Indonesian, plays a significant role in representing Indonesia's national identity. The term “budaya” is derived from the Sanskrit word “buddayah,” which means thought or intellect [2]. Culture can be broadly defined as the result of human thought or intellectual activity, which is cultivated and transmitted across successive generations.

Culture has a significant association with religion. In Indonesia, which boasts the largest Muslim population globally, many cultural practices are significantly influenced by Islamic traditions. The kupatan tradition is one such example. This tradition represents a cultural heritage that continues to be practiced by Muslim communities, particularly during the celebration of Eid Al-Fitr. Moreover, the kupatan tradition is commonly practiced among the Javanese as a way to offer thanks to Allah Subhanahu Wa Ta’ala (Glory to Him, the Exalted) for the abundance of blessings granted [3]. In Javanese religious practice, the kupatan tradition carries a philosophical significance, representing the integration of Javanese cultural values and Islamic principles [4].

Ketupat or kupat serves as a symbolic dish within the kupatan tradition. Ketupat is a rice-based food encased in the woven leaves of young coconuts, known as janur in Javanese [5]. Ketupat is strongly connected with the Eid celebrations, embodying the concepts of forgiveness and blessings [6]. Ketupat is defined as “Jarwa dhosok,” a term that signifies “ngaku lepat,” reflecting the concept of admitting mistakes [7]. In this context, the practice conveys the importance of apologizing for mistakes. This custom has become an established tradition on the first day of Shawwal or Eid Al-Fitr. Ketupat is referred to as “kupat” in Sundanese, a term that implies avoiding “Ngupat,” which denotes speaking negatively about others.

Alongside the kupatan tradition, the practice of consuming ketupat is also widespread throughout Indonesia. Furthermore, each region has its unique method of enjoying this dish. In Central Java, ketupat is typically wrapped in triangular-shaped bamboo leaves and paired with sambal made from grated coconut. Ketupat is a central ingredient in several regional specialties, such as kupat tahu (Sunda), karetat karetan (Banjar), grabag (Magelang), kupat glabet (Tegal), and coto Makassar (Makassar) [8]. These variations are essential to the identity of the local cuisine, often closely associated with the people who consume it [6]. Several reviews on ketupat have been published, primarily focusing on its anthropological aspects from historical, philosophical, and culinary traditions perspectives. However, despite its significant cultural importance, comprehensive studies on ketupat remain underrepresented in international databases. This review aims to delve into the multifaceted aspects of ketupat, covering not only its socio-cultural significance but also its preparation methods, physicochemical and microbiological properties, safety and shelf-life considerations, as well as the challenges and potential for its further development.

Methodology

This review critically analyzed and synthesized resources gathered from a range of databases and search engines, including Google Scholar, ScienceDirect, Springer, Wiley Online Library, Web of Science, and Garuda Kemendikbud. The primary focus of this review encompasses the socio-cultural aspects, philosophy, cooking processes, physicochemical changes during processing, shelf-life and safety considerations, as well as the challenges and future prospects of ketupat. The literature reviewed spans publication years from 1985 to 2024. The inclusion criteria for this review were research articles published in peer-reviewed journals, conference proceedings, or books. Studies that were not available in English or Indonesian were excluded. During the literature search, keywords such as “ketupat” (history, origin, philosophy, nutrition, processing technology), “kupatan,” “slametan,” “Eid tradition,” and “Ngupati tradition” were used to identify relevant studies in both Indonesian and English. To provide additional context, a map of Java Island (highlighted in yellow) was created to illustrate the regions where ketupat was first introduced and where the kupatan tradition, with ketupat as its iconic dish, gained popularity among the general public.

Ketupat as traditional Indonesian food

Traditional food is a vital aspect of a nation's cultural identity, embodying the flavors, techniques, and customs passed down through generations [9]. In Indonesia, a country rich in cultural diversity, traditional foods are more than just sustenance, they are a reflection of the country’s history, geography, and the ethnic mosaic that makes up its population [10]. Traditional foods are those that have remained largely unchanged over time, prepared using methods that have been preserved and handed down through families and communities. These foods often incorporate local ingredients and are deeply intertwined with cultural rituals, festivals, and daily life [9]. Indonesia’s culinary heritage is vast, with each region offering its own unique dishes. Some of the most famous traditional Indonesian foods include rendang, a spicy beef dish from West Sumatera [11]; nasi goreng, the Indonesian fried rice [12]; satay, skewered and grilled meat served with peanut sauce [13]; and gado-gado, a vegetable salad drizzled with a savory peanut dressing [12]. These dishes, among many others, are celebrated both within Indonesia and abroad, highlighting the country’s rich culinary tradition.

The continued existence and popularity of traditional foods in Indonesia can be attributed to several factors. Firstly, these dishes are deeply ingrained in the country’s cultural and social fabric, often linked to religious practices, family gatherings, and national celebrations. Secondly, there is a strong sense of pride and responsibility among Indonesians to preserve their culinary heritage, leading to the transmission of traditional recipes and cooking techniques from one generation to the next. Additionally, the use of locally sourced ingredients ensures that traditional foods remain accessible and affordable, further contributing to their longevity [14].

Among the many traditional foods in Indonesia, ketupat stands out as a significant culinary symbol, especially during festive occasions like Eid al-Fitr. Ketupat is a type of rice dish, made by boiling rice wrapped in a woven coconut leaves pouch until it becomes firm and takes on its distinct diamond shape. This process not only requires skill but also carries cultural significance, as the act of weaving the leaves and cooking the rice is often done communally, fostering a sense of togetherness. Its unique preparation method and cultural significance make ketupat a cherished and enduring element of Indonesia's culinary heritage [15]. Ketupat is typically served with a variety of dishes, such as rendang (spicy beef), opor ayam (chicken in coconut milk), and sayur labu (chayote stew) (Fig. 1). Its subtle flavor and firm texture make it an ideal accompaniment to the rich, spiced dishes common in Indonesian cuisine. Beyond its culinary appeal, ketupat also holds symbolic meaning. In many parts of Indonesia, it is seen as a representation of purity and forgiveness, making it a central part of rituals and celebrations. The tradition of preparing and sharing ketupat during special occasions testifies to its enduring place in Indonesian culture. Its continued prominence in Indonesian society reflects the deep connection between food, culture, and community, serving as a reminder of the importance of preserving these culinary traditions for future generations [16].

Fig. 1

Ketupat, with its subtle flavor and firm texture, pairs perfectly with a range of Indonesian dishes. Its versatility makes it an ideal companion to the rich and spiced flavors that characterize Indonesian cuisine (source: image by Dewi Ambarwati on freepik.com)

Socio-cultural aspects of ketupat

A diverse array of customs, traditions, and religious rituals is widespread throughout Indonesian society [17]. Muslim communities on the island of Java celebrate each religious ritual in a unique manner, as exemplified by the slametan (thanksgiving) ritual. Slametan associated with major Islamic days or months is frequently observed through the kupatan tradition, as seen during Eid Al-Fitr [3, 18]. In Javanese tradition, Eid Al-Fitr is known as riyaya or bhada. The term riyaya comes from the Indonesian word "ria", which signifies joy and gratitude. Bhada, derived from the Arabic word “ba’da,” meaning “after,” is categorized into two types: Eid bhada and kupat bhada [7]. Eid bhada is observed on the first day of Eid Al-Fitr with prayers and silaturahmi (visiting and socializing), while kupat bhada is celebrated a week later by sharing ketupat with each other [19]. Subagya [7] outlines three main purposes of the kupatan tradition. The first is to serve as a means of communication and strengthening social bonds, as evidenced by the enthusiasm of the Javanese people in participating in this tradition, particularly during the Eid Al-Fitr celebration. The second purpose is to facilitate charitable giving, demonstrated by the act of sharing as an expression of gratitude for the blessings received. Lastly, the third purpose is to preserve cultural heritage and customs, as this tradition has been passed down through generations.

The kupatan tradition encompasses several aspects of multicultural values, each having a significant impact on human existence. The religious dimension is one key aspect, with kupatan serving as a customary practice to express gratitude to Allah SWT. The second aspect is spiritual, involving the acknowledgment of mistakes and mutual forgiveness. This concept is particularly important for fostering a culture of forgiveness among those who participate in the tradition. Another spiritual aspect is the concept of light, as reflected in the word “janur”, derived from the Arabic term “ja'a nur,” meaning the arrival of radiant light. The kupatan tradition symbolizes the human aspiration for enlightenment and guidance from Allah SWT. The final aspect pertains to the social dimension, where cooperation plays a crucial role in achieving the social goals. The kupatan inherently promotes the principles of teamwork and friendships [7].

The kupatan tradition is a crucial component of Eid celebrations in Indonesia, especially within Javanese communities. Java Island is recognized as the origin of the kupatan tradition in Indonesia. The practice of this tradition varies across different regions in Indonesia, each with its unique characteristics, although it generally coincides with a similar timeframe, specifically one week after Eid Al-Fitr, known as “kupat bhada” [19]. However, the timing can differ based on local customs and the Islamic calendar used. For instance, in the Kaliwungu area of Central Java, ketupat sumpil is commonly served during the Maulid of Prophet Muhammad SAW celebrations. Unlike in Kaliwungu, ketupat sumpil is more commonly served during Eid al-Fitr in Purworejo and Kebumen. It is also typically served at weddings in Temanggung. The name ketupat sumpil comes from a snail-like creature found in rivers, known as “sumpil” in Javanese. The food is named ketupat sumpil because its small size and shape resemble the snail [20]. In Malang, East Java, the well-known ketupat dish for Eid is orem-orem. However, orem-orem is also widely sold as a daily menu item in the Klojen area of Malang [21]. In Sundanese culture in West Java, ketupat is commonly referred to as kupat and is frequently paired with tofu dishes, known as kupat tahu. This dish is not just for Eid al-Fitr but is also commonly featured in daily breakfasts. It typically includes ketupat, fried tofu, vegetables, bean sprouts, and peanut sauce and is usually topped with crackers [22]. Although there are differences in culinary traditions, kupatan is broadly a time for gathering, celebrating, and strengthening social connections within the community.

The philosophy of ketupat

Ketupat was first introduced in the fifteenth to sixteenth centuries by Sunan Kalijaga [19], one of the nine Islamic saints on the island of Java (Fig. 2). Today, ketupat is not only prevalent on Java but has also spread across various regions throughout Indonesia. In Javanese, the word ketupat is derived from the term papat, which means four. This refers to the essence of the fourth pillar of Islam, the Ramadan fast, symbolized by the square shape of the ketupat. Ketupat is also interpreted as “ngaku lepat,” which reflects the concept of admitting mistakes [7]. In Arabic, kupat is the plural form of the word "kafi," which translates to "kuffat," meaning "sufficient." In this context, it symbolizes the hope for adequacy following the Ramadan fast and serves as a significant symbol of mutual forgiveness. Ketupat symbolizes gratitude and an apology to both Allah SWT and fellow humans, which is why it is frequently present during Eid Al-Fitr—a period when Muslims strive for purification and mutual forgiveness.

Fig. 2

Ketupat was first introduced by Sunan Kalijaga, a revered Indonesian theologian and an influential figure for Muslims on Java Island. This traditional rice dish became an integral part of Javanese culture, particularly during the celebration of Eid Al-Fitr, A illustration of Sunan Kalijaga, the prominent figure responsible for introducing ketupat (source: selingkarwilis.com), B geographical representation of Java Island, Indonesia, where the kupatan tradition and ketupat first emerged

The symbolic meaning of ketupat originates from "laku papat", which refers to four specific actions: lebaran, luberan, leburan, and laburan. The first action is lebaran, derived from the word "lebar", indicating that the doors of forgiveness are widely open. Lebaran also signifies the end of the fasting month, marked by the consumption of ketupat. The second action is luberan, derived from the word "luber", meaning abundance. This signifies that one should give generously to those less fortunate. The third action is leburan, derived from the word "lebur", which means to forgive. On this day, all offenses are forgiven, as it is essential for everyone to extend forgiveness to others. The fourth action is laburan, which signifies that individuals return to a state of purity and are free from sin [23].

Ketupat embodies several philosophical meanings, from its intricate weave to its accompanying dishes. The complex weaving of its wrapper symbolizes human errors, while the white rice inside represents the purity and cleanliness of the heart after forgiving others. The diamond-shaped form of the ketupat signifies the triumph of Muslims after a month of fasting leading up to Eid Al-Fitr. Additionally, its greenish-yellow wrapper is considered a protective charm against misfortune or evil. The practice of hanging ketupat after cooking it in front of the house is symbolically seen as a method for warding off evil spirits. This custom serves as a protective measure to keep malevolent forces away from the household [6]. Ketupat is frequently prepared using different methods, including cooking it with coconut milk (santan) rather than water. In Javanese tradition, coconut milk represents a request for forgiveness, as the Javanese word "santen" signifies "pangapunten", which translates to apology or forgiveness.

The process of cooking ketupat

Ketupat is prepared using "pulen" rice, which is glutinous with a smooth texture and contains a low to moderate amount of amylose. Another type of rice, known as "pera" with hard texture and high-amylose content, is also utilized in various regions across Indonesia [6]. According to Juliano [24], rice is categorized into low-, medium-, and high-amylose content based on the proportion of amylose to total starch, with ranges of 12–20%, 20–25%, and 25–33%, respectively. Studies have recently demonstrated that rice with a high-amylose content is typically firmer and less sticky, whereas rice with a low-amylose content is usually softer and stickier. However, both pulen and pera rice varieties in Indonesia are characterized by their long grains, in contrast to the short-grain rice typically found in Japan and Korea. Short grains are generally known for being sticky, whereas long grains are typically recognized for their non-sticky texture [25].

The process of cooking ketupat is illustrated in Fig. 3. The rice was initially washed two to three times and then drained. This washing process effectively eliminates foreign particles, which enhances both consumer satisfaction and the shelf-life of ketupat. The rice was packed into woven coconut leaves (janur) and filled approximately one to two-thirds of the container's volume. Janur, obtained from the upper part of the coconut tree, requires two long leaves to create the woven pouch. It is preferred due to its flexibility and adaptability in forming various shapes, while older coconut leaves are stiff, tend to break easily, and are less suitable for the weaving process. The amount of rice filling in the janur influences the texture of the resulting ketupat. Insufficient rice filling leads to a softer texture, while excessive filling results in a firmer texture. Ketupat is submerged in water until fully soaked and then boiled for approximately 5 h. This cooking process transforms the rice grains into a compact and elastic texture, unlike regular rice, which is typically softer and a bit sticky. Ketupat is then rinsed with clean cold water to remove any residual cooking water and then hung up to dry, which helps prevent spoilage.

Fig. 3

The traditional process of making ketupat involves cooking rice wrapped in young coconut leaves (janur) in boiling water for five hours. This time-honored tradition is deeply rooted in Indonesian culture, especially during Eid Al-Fitr celebrations, when ketupat is prepared and shared as a symbol of unity and blessings

Traditional cooking methods for ketupat are fuel-inefficient due to their extended cooking times. Moreover, the cooking temperature is inherently unstable due to the need to add water to the pan throughout the cooking process to keep the ketupat submerged throughout the process. Furthermore, the skills required for weaving coconut leaves, inserting rice into the woven leaves, and cooking ketupat are specialized. This complexity often deters people from preparing ketupat on their own.

Physicochemical transformation during cooking of ketupat

The preparation of ketupat, which consists of rice wrapped in coconut leaves and subjected to cooking, involves several physicochemical changes. As the cooking progresses, the rice starch undergoes gelatinization. Starch, which begins in a crystalline state, absorbs water and expands, ultimately converting into a gel. This process of gelatinization is vital because it alters the rice’s texture from firm to tender and elastic [26]. Starch gelatinization also induces changes in the molecular structure of starch. Both amylose and amylopectin within the starch undergo structural modifications, which impact the consistency and chewiness of the ketupat [27]. The cooking methods, such as the amount of water used, heating temperature, and cooking duration, had a significant impact on the texture of ketupat as a processed rice product. The cooking of ketupat in an excess of water enhances the intensity of the gelatinization process. This heightened gelatinization leads to an increased absorption of water by the starch, resulting in excessive swelling and the formation of a less cohesive gel. Consequently, the texture of the ketupat becomes excessively soft and prone to disintegration [28]. Under typical gelatinization conditions, amylose dissolves into the water, whereas amylopectin creates a gel network that provides elasticity. In contrast, when excess water is present, amylose leaches more extensively into the water, leading to a decrease in both the elasticity and structural integrity of the gel [29]. The cooking process significantly enhanced the swelling behavior of waxy rice (low-amylose content), while it reduced both the swelling behavior and amylose leaching in high-amylose rice. An increase in cooking temperature led to a significant rise in the amount of rapidly digestible starch. Gelatinization temperature was also positively correlated with cooking temperature and time, whereas pasting properties was negatively correlated with temperature and time [26]. The cooking process of ketupat is believed to involve similar mechanisms as those observed during rice cooking, but with a longer duration, resulting in a denser texture [30, 31].

Shelf-life and safety aspect of ketupat

The shelf-life of ketupat is limited, generally extending to approximately 2 to 3 days under ambient temperature conditions [6]. The high moisture content of ketupat (64.80%) makes it a conducive medium for microbial growth [32]. As with any food products, the microbiological aspects of ketupat are crucial in ensuring food safety and preventing foodborne illnesses. The presence of microorganisms, particularly Staphylococcus aureus and Bacillus cereus, in substantial numbers can cause food poisoning [33], with these bacteria capable of proliferating rapidly in cooked rice that is inadequately stored or stored at room temperature for extended periods [34]. Preventing the growth of pathogenic bacteria in ketupat requires strict adherence to proper food handling and preparation practices. Crucial steps include maintaining cleanliness and sanitation of all equipment and surfaces, cooking the rice to the appropriate temperature, and ensuring the finished product is stored at safe temperatures. To prolong the shelf-life of ketupat, it is recommended to eliminate residual cooking water following the cooking process, and subsequently store it in a dry, airtight container. The shelf-life of ketupat can be further extended by incorporating salt as a preservative into the cooking water or by storing the ketupat at a low temperature, around 4 °C [32].

Ketupat stored at a low temperature will have an extended shelf-life, ranging from 4 to 7 days [6]. Before storage, it is advisable to place the ketupat in a dry, airtight container. After being stored at a low temperature, ketupat can be consumed following a 30-min reheating period. This is because the ketupat will develop a firmer texture due to starch retrogradation. Retrogradation involves the reestablishment of hydrogen bonds between amylose and amylopectin molecules within the starch gel, and the cooling process increases the strength of these hydrogen bonds [35]. The mechanism of strong reorganization of starch molecules, including amylose-amylose, amylose-amylopectin, and amylopectin-amylopectin interactions, makes starch more resistant to digestion, resulting in the formation of resistant starch type III (RS3). Resistant starch comprises a portion of starch or its degradation products that remains unabsorbed in the healthy small intestine and resists to digestive tract enzymes. It is also categorized as a type of dietary fiber [36]. Scientific evidence has demonstrated that resistant starch provides numerous health benefits, including reducing the risk of colorectal cancer, regulating macronutrient metabolism, enhancing hormone secretion, decreasing the presence of harmful microorganisms in the gut, lowering fecal fluid toxicity, and mitigating laxative effects. Resistant starch can enhance the immune system, promote the growth of Lactobacillus and Bifidobacterium colonies, and improve the absorption of calcium (Ca) and magnesium (Mg). It can also function as a prebiotic, providing a substrate for microorganisms in the large intestine. Butyrogenic genera present in the human colon can utilize resistant starch to produce short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate, which possess anticarcinogenic properties [37].

Challenges and future prospects of ketupat

One of the major challenges in the development of ketupat is integrating modern technology into traditional production methods. Although traditional practices preserve cultural heritage, they may not satisfy current needs for efficiency and scalability. Implementing innovative technologies for both production and processing is crucial, although it may face resistance due to a strong commitment to established practices. Furthermore, the traditional method of producing ketupat demands specific expertise, such as the weaving of young coconut leaves. As these skills may diminish over time, the challenge of training new artisans could lead to the loss of the traditional values and philosophical significance of ketupat. Maintaining quality and food safety standards throughout the production process, including preventing microbial contamination and ensuring adequate shelf-life, is also a significant challenge in ketupat production.

Predicting the future of ketupat is challenging due to factors such as market competition, consumer demand, etc. However, its future prospects can be evaluated from several perspectives, including sustainability and tradition, product innovation, global market expansion, and the adequacy of infrastructure and logistical support. Regarding sustainability and tradition, ketupat has the potential to preserve Indonesian culinary heritage while incorporating sustainable practices into its production. Emphasizing the use of local and eco-friendly ingredients, along with production techniques that honor cultural traditions, can enhance its unique appeal. As technology and research progress, there are opportunities to create more innovative varieties of ketupat, including those with healthier ingredients. Exploring more efficient and environmentally sustainable processing methods could also lead to ketupat products that are more attractive to contemporary consumers [32, 38]. Additionally, the growing global recognition of Indonesian cuisine could enhance the potential for ketupat's popularity in international markets [39]. Effective promotion and marketing efforts can facilitate the introduction of ketupat as a global culinary offering, particularly in countries with Indonesian communities or a strong interest in ethnic cuisines. Additionally, developing infrastructure for the production and distribution of ketupat can enhance product accessibility and quality. Investment in advanced packaging and distribution technologies can enhance the preservation of ketupat’s freshness and broaden its market reach. Moreover, continued scientific research into ketupat can identify opportunities for advancements in safety, shelf-life, and overall product quality. By capitalizing on these opportunities, ketupat could experience significant development and strengthen its position in the food industry, both locally and globally.

Conclusion

Ketupat, a traditional rice-based dish wrapped in young coconut leaves (janur), is a significant part of Indonesian culinary heritage. It is not only a distinctive food for Eid Al-Fitr, but also embodies several multicultural dimensions. These include religious aspects as a form of gratitude, spiritual aspects as an acknowledgment of faults, individual significance as a pursuit of enlightenment, and social value as a symbol of fellowship. Due to its traditional cooking methods, ketupat exhibits a short shelf-life, making proper handling and storage is crucial to prevent the growth of harmful bacteria and extend its shelf-life. To advance its development, focusing on sustainable production practices, product innovation, efficient processing techniques that retain its cultural values, and effective marketing strategies are crucial. This review underscores these points and encourages further research into ketupat.