Diversity of Indonesian offal-based dishes

Abstract

Indonesia is a home to diverse ethnicities and cultures that have influenced its culinary tradition. Moreover, Indonesian culinary tradition is shaped by the country’s wealth of natural resources, one of which is offal (including tripe, lung, intestine, liver, and so on). The utilization of offal has created myriad recipes of offal-based dishes (OBDs), resulting in a culinary diversity across the nation. Therefore, this article aimed to identify and create a culinary profile of Indonesian OBDs based on geographical distribution. To strengthen this culinary profile, historical creations of Indonesian OBDs were also elucidated. For centuries, Indonesian OBDs have been shaped by several factors, such as natural resources, history, religio-cultural, and economic backgrounds. For instance, specialties such as momoh (braised offal) from Central Java and pallubasa (coconut milk-based offal soup) from South Sulawesi were developed due to religio-cultural and economic reasons, respectively. Although 139 Indonesian OBDs are widely distributed across 23 Indonesian provinces, the foods are mostly concentrated in West Sumatra (31 dishes), Central Java (18 dishes), and East Java (14 dishes). Furthermore, intestine, liver, and tripe are the most commonly used types of offal as utilized in over 40 dishes; while cattle, water buffalo, and chicken are the most utilized sources of offal. Meanwhile, pig offal is only used in the non-Muslim regions of Indonesia. The creation of Indonesian OBDs is also influenced by foreign cultures. For example, gulai tambusu (intestine curry) from West Sumatra, rabeg (Bantenese-styled mutton curry) from Banten, babat gongso (stir-fried cattle tripe) from Central Java, and the ubiquitous sop buntut (oxtail soup) demonstrate Indian, Arabian, Chinese, and colonial influences, respectively. However, OBD such as saksang (pork stewed in pig blood), which originated from Batak ethnic group, retains the native culinary features. Additionally, OBDs recipes involve several spices, herbs, and other ingredients that can maintain and improve their organoleptic attributes.

Introduction

Indonesia is the largest archipelagic country in the world, with a megadiverse population and a wealth of natural resources [1]. It is located in a strategic position between two large continents (Asia and Australia) and two vast oceans (Pacific and Indian Oceans) [1]. Moreover, the country covers a total area of 7.81 million km² (which is about three quarters of the European continent), consisting of over 17,000 islands and inhabited by over 250 million people (i.e., about 3.5% of the world’s population) from more than 1300 recognized ethnic groups [2]. This diversity is a remarkable potential source of power for the country, which is reflected in its national motto “Bhinneka Tunggal Ika,” (a phrase in Ancient Javanese that translates to “Unity in Diversity”) [2]. The diversity of Indonesian culinary tradition is also a national asset that reflects the wealth of its cultural heritage [3]. Over centuries, more than 5300 traditional dishes have been developed across Indonesia in the support of diverse natural, historical, cultural, and gastronomical backgrounds [3, 4].

One of Indonesia’s foremost natural resources is livestock. Animal husbandries are established across many regions in the country to fulfill the national demand for protein sources (such as meat, egg, milk, etc.). In 2020, the population of livestock in Indonesia was estimated to be over 400 million, consisting of cattle, water buffalos, goats, sheep, pigs, chickens, ducks, geese, horses, and more [5]. Meanwhile in 2021, Indonesian animal husbandries had produced over 1.2 million tons of high-quality meats from different animals [5]. Another potential output of the animal production system is the variety of offal, which is considered a by-product. As the weight of offal is nearly half of the animal’s total weight, it is estimated that over 1.2 million tons of offal were produced by the Indonesian animal production system in 2021 [5, 6]. Thus, these abundant raw materials could be used as an affordable alternative source of protein.

Offal has long been used and incorporated into many Indonesian traditional dishes, which have historically been shaped by the country’s history, cultural background, and natural resources [3, 7]. Moreover, offal-based dishes (OBDs) have become an ethnic specialty in some Indonesian regions due to their uniqueness and authenticity [3, 7]. Initially, offal was considered a low-cost food ingredient [8]. As most Indonesian people were historically poor, they faced financial difficulties in affording the finest ingredients for their basic nutritional needs [8]. Therefore, offal became an affordable solution as a low-price source of protein for Indonesian families. However, a recent cultural shift has caused perceptions toward offal to change drastically, as it is currently considered a unique or even luxurious food [9, 10].

This literature review aimed to identify and establish a culinary profile of 139 Indonesian OBDs based on their geographical distribution, which was collected through several literature sources. In some Indonesian regions, OBDs creation is influenced by various histories, culinary traditions, economic and cultural backgrounds, which is also an aspect that was elucidated in this review. The recent development of Indonesian OBDs was also reviewed in this article. Furthermore, this culinary profile is the first study comprehensively reporting the diversity of Indonesian OBDs which are essential to enrich the national and international gastronomic databases that have not been studied before. Moreover, the article can potentially be the future reference since providing any meritorious information for those working in the related studies (food science, ethno-culinary science, gastronomy and cultural science).

In general, the review article includes research backgrounds and methodology used in the study. Then, the article attempts to highlight the perspective of Indonesian OBDs from historical and cultural aspects and their regional distributions through a number of scientific discussions. The article also provides conclusive statements of study and also future recommendations.

Methods

The manuscript is a literature review focusing on developing a culinary profile of Indonesian OBDs based on their geographical distribution, history, culinary tradition, economic and cultural backgrounds. Information related to Indonesian OBDs was collected from books, websites, academic journals, and online documents. Data from online sources were searched using keywords and Boolean expression logics, such as “Indonesian foods made of offal”, “Indonesian foods made of a particular type of offal” (for example: “Indonesian foods made of liver”), “offal-based foods from a particular Indonesian region” (for example: “offal-based foods from South Sulawesi”), “history of a particular Indonesian OBDs” (for example: “history of pallubasa”), “cultural/economic backgrounds behind the creation of a particular Indonesian OBDs” (for example: “cultural backgrounds of momoh”/“economic backgrounds behind the creation of soto tangkar”) and combination of those keywords. Meanwhile, data from offline sources were manually searched using similar principles as that of online sources. This article used offline and online literature sources from 1965 to 2023.

The data were collected, selected and grouped into categories as follow: names of dishes, geographical origins, sources of offal, types of offal, the use of offal in the dishes (main, secondary and alternative ingredients), recipes, and preparations of Indonesian OBDs. Other data related to historical, culinary tradition, economic and cultural backgrounds of Indonesian OBDs as well as other supporting information (including the recent development of Indonesian OBDs) were also collected to support the study. Data were processed using Microsoft Excel version 2016 and presented in figures, tables and pie diagrams.

To verify the data and strengthen the literature study, a number of mini-field observations and interviews were further conducted (Additional file. 3). The mini-observations and interviews were conducted in the city of Yogyakarta (Indonesia) which represents the multi-ethnicity of Indonesia as many ethnical-based food restaurants (including OBDs restaurant) have been established in the city [2, 11, 12]. The interviewees were people working in the related areas (chefs, food entrepreneurs and gastronomic experts).

Books used in this study consist of cookbooks, recipe books, and other books (especially related to history, foods history, foods cultures and gastronomy). Information was also gathered from websites (especially related to recipes, history, cultural significance and also recent development of Indonesian OBDs). Meanwhile, online documents were reports, statistical data and religious laws that support the study. In terms of academic article, the articles were collected and selected from Q1 to Q2 (Scimago indexing) and SINTA 1–2 (Indonesian national journal indexing) journals for international journal and national journal, respectively. Meanwhile, other articles were collected from Crossref database due to accessibility and selectivity.

Results and discussions

The history and development of Indonesian offal-based dishes

According to the Encyclopedia Britannica, offal can be described as non-meat materials of a slaughtered animal, including brain, blood, heart, kidney, liver, spleen, lung, tripe, intestine, gizzard, trotters, skin, feet, and tongue [13]. In some cultures, the definition is further extended to include head skin, lip, bone, bone marrow, testicle, nipple, tendon, ovary, and more [6, 14]. In some cultures, offal is considered an impure food and a method of humiliation, while other cultures regard it as a delicacy [10, 14, 15].

Due to its strategic location, Indonesia has become a confluence of many cultures (such as Indian, Chinese, Arabian Islamic, Polynesian, colonial European, and indigenous cultures), which has enabled many instances of acculturation. This acculturation also impacts on the Indonesian culinary tradition, where numerous dishes (including OBDs) have been developed based on myriad recipes as a result of the acculturation of different cultures (including in the development of OBDs) [3].

In the first century BC, Indians arrived in maritime South East Asia for economic reasons and, according to historians, contributed to the spread of Indian religions and cultures in the area [16]. Indonesian inhabitants further adopted Indian religions in syncretization with local folk religions and animist beliefs. Notably, entire religious laws and liturgical activities have not been strictly adopted in Indonesia [16]. For example, Indonesians have rejected the stringent concept of caste, viewing caste (varna) as a functional group rather than a social hierarchy [16, 17]. This cultural adaptation has also affected Indonesia’s dietary and culinary culture. In India, some adherents of Hinduism, especially those belonging to higher castes such as Brahmins (priests and teachers) and Kshatriyas (administrators and warriors), follow a diet based on a strict principle of lacto-vegetarianism (only consuming dairy and vegetarian-based foods) [18]. According to the Ahimsa law (i.e., the principle of non-violence), animal slaughtering for daily consumption is considered inhumane [18]. Therefore, the daily consumption of meat and organs (offal) is only allowed for the middle caste (Vaishyas, for farmers and merchants) and the lower caste (Shudras, or laborers and slaves), respectively; since higher castes may not do the inhumane activity [18]. Additionally, in Hinduism, inner organs are considered impurities that can only be eaten by the lower caste [18]. However, this principle of lacto-vegetarianism has only loosely been adopted in Indonesian Hindu communities (only followed by limited sectarians of the Brahmin caste) [17, 19]. Meanwhile, the influence of South Indian curry can only be discovered in some places in Indonesia such as Sumatra, coastal Kalimantan, and parts of Sulawesi [3]. This is probably because this curry was only gastronomically acceptable by the people in those areas in the early period of India-Indonesia contact [20]. Interestingly, Indonesian curries are mostly made in a coconut milk basis, which is similar to the preparation of South Indian curries [20].

An example of curry-like dishes in Indonesia is the Minangkabau cuisine found on the island of Sumatra. It is claimed that the ancestors of gulai (a Minangkabau curry) and kalio (a spicy Minangkabau curry) were probably developed as far back as the eighth century utilizing non-halal and water buffalo meats [20]. However, the use of offal in the Sumatran curry has not been literally recorded. The Minangkabau people consider the water buffalo as a symbol of strength; therefore, the consumption of this meat is believed to empower people [21]. Moreover, the non-halal meats that were most probably utilized to prepare the ancient version of curry were pork, wild boar, dog, reptiles, and more, which are usually consumed by their Bataknese counterparts who live in the hinterland of Sumatra [20]. In contrast, Bataknese people tend to retain their Austronesian culinary tradition, which involves the use of animal blood and pork [22, 23]. The utilization of offal is discovered in some Bataknese dishes, such as saksang (pork stewed in pig blood) (Fig. 1A) and lomok-lomok (Bataknese pork and pig offal stew) (Table 1). In this context, offal is seen to play a pivotal function in strengthening the tondi (soul) [23]. The main characteristic of Bataknese traditional cuisine is the use of pungent andaliman (Zanthoxylum acanthopodium), which has been in use long before the introduction of chili pepper (Capsicum annum) [22]. With the arrival of Islam in Sumatra in the thirteenth century (especially in Aceh as well as the eastern and western coasts of Sumatra), halal meats began to be utilized in dishes, including curry [20, 21]. Consequently, offal of halal animals also began to be widely consumed since it is considered halal and its usage could avoid a food disposal (mubadzir) [24, 25]. Offal can be discovered in number of recipes of gulai and kalio, such as gulai otak (brain curry), gulai tambusu (intestine curry) (Fig. 1B), kalio babat (tripe spicy curry), and kalio usus (intestine spicy curry) (Table 1). As there is a tradition among Minangkabau people to wander outside their homeland (merantau), a relatively preserved version of the spicy curry (kalio) was created in a drier basis, popularly known as rendang (dried spicy curry) [21]. Philosophically, the long duration involved in processing rendang is considered to be a symbol of patience [20]. The history of rendang creation has been well-documented in the Hikayat Amir Hamzah (from around the fifteenth century) [21]. Offal is also used in rendang, such as in rendang hati (dried liver spicy curry) and rendang babat (dried tripe spicy curry) (Table 1). In 2017, the readers of CNN Travel voted rendang as the world’s most delicious food [26].

Fig. 1

Saksang (pork stewed in pig blood) from North Sumatra (A); gulai tambusu (intestine curry) from West Sumatra (B); lawar (Balinese mixed vegetable with grated coconut flesh) from Bali, added with pig blood (C); rujak cingur (lip salad) from East Java (D). momoh (braised offal) from Central Java (E); rabeg (Bantenese-styled mutton curry) from Banten (F); babat gongso (stir-fried cattle tripe) from Central Java (G); coto Makassar (Makassar-styled beef soup) from South Sulawesi, also utilizing offal (H); The ubiquitous bakso jeroan (meatballs with offal topping) (I)

Table 1 The Indonesian OBDs based on their origin, offal source, type of offal, and their utilization in the dish

Initially, instead of adopting the Indian curry, Javanese and Sundanese people tended to develop their indigenous dishes [17]. Some ancient Javanese delicacies, which were usually served during religious offerings and royal dining banquets, have been recorded in a number of ancient inscriptions (AD 900–928) from the Mataram Kingdom (AD 716-1016). Some examples include wrak-wrak (interpreted as the modern urap/lawar, or mixed vegetables with grated coconut flesh), rarawan (interpreted as the modern rawon, or meat soup spiced with Pangium edule), rurujak (interpreted as the modern rujak, or spicy salad), hadanan madura (buffalo meat cooked in a sweet palm sugar), and dundu puyengan (eel cooked with lemon basil) [70]. Unfortunately, the presence of OBDs in ancient Java has not been clearly documented in any inscription. The ancient use of offal in dishes can be traced from the modern versions of ancient Javanese dishes as well as their Balinese counterparts, as the Balinese culture is a continuation of the ancient Javanese Hindu civilization [19]. For instance, the utilization of blood in lawar (Balinese mixed vegetable with grated coconut flesh) and pig offal in rawon babi (Balinese pork rawon) proves that offal was probably used in the ancient dishes (wrak-wrak and rarawan, respectively) (Table 1) [59]. This is also supported by the fact that in East Java, cattle offal (tripe, liver, and intestine) is often incorporated into the halal version of rawon as a secondary source of protein along with beef [52]. Meanwhile, in minority non-Muslim Javanese communities, rujak is often served with fried saren (blood pudding) [70]. It is hypothesized that offal had been consumed by the common Javanese people in ancient times but was probably not served during rituals and in royal palaces because it was considered impure (hence, not mentioned in the inscriptions) [70]. In contrast, the sacred offerings and imperial tables usually served the finest parts of an animal (i.e., the meat) [70]. Interestingly, today, the Balinese lawar merah (lawar mixed with blood) (Fig. 1C) is not only a delicacy for the common people but also favored by Balinese royal families and used as an offering during rituals, which demonstrates that offal is more acceptable by Balinese higher societies rather than their ancient Javanese counterparts [59]. Even the tradition of cooking lawar collectively (nglawar) is viewed as a concept to enhance the unity of Balinese people coming from different backgrounds [59, 71]. Meanwhile, in Western Java, offal is added in Sundanese delicacies such as piritan (steamed vegetables and fish offal wrapped in banana leaf), pais (steamed meat and vegetables wrapped in banana leaf), and bobotok (steamed shredded coconut flesh wrapped in banana leaf), all of which have a historical tie to the ancient Pajajaran Kingdom (Table 1) (thirteenth–fifteenth century) [72].

In the period of Islamization in Java (around the fifteenth century), non-halal ingredients were entirely omitted from the indigenous dishes [70]. In Islamic dietary law (halal law), the consumption of pork and blood is strictly prohibited [73]. The incorporation of saren (blood pudding) in rujak, for example, was probably replaced with cingur (the lip of water buffalo), which has a similar meaty characteristic (Table 1, Fig. 1D) [48, 70]. Meanwhile, the rulers of some Islamic sultanates in Java also decreed a law banning cattle slaughtering as a religious tolerance to honor Hindu communities in their realms [46, 70]. In Hinduism, cattle are venerated since regarded as the incarnation of Nandi Deva (the bull of Lord Shiva); hence, the cattle slaughtering is forbidden [17]. Therefore, the Muslim citizens slaughtered water buffalo, goat, sheep, and other halal animals instead, even developing dishes based on their meat and offal [46]. An example comes from Kendal Regency, located on the northern coast of Central Java, in which momoh (braised offal) was historically created from water buffalo offal in the early period of Islamization (around fifteenth–sixteenth century) (Table 1, Fig. 1E) [46]. Momoh is derived from the Javanese word for rejection, “emoh,” which historically signifies an initial rejection of the dish due to its dark brown appearance [46]. The offal is slowly cooked for up to two days in a sweet palm sugar-based seasoning, which is reminiscent of the ancient Javanese dish of hadanan madura (tenth century) [46, 70]. Curry-like dishes were probably developed in Java after the arrival of Arab, Indian, and Malay Muslim traders, who introduced Islam to the region [46, 70]. It has been suggested that the late adoption of curry in Java was to create a cuisine with a new religio-cultural identity (Muslim cuisine) that could be differentiated from indigenous Hindu cuisine [46, 70]. For instance, rabeg (Bantenese-style mutton curry) is a delicacy developed by the people of Banten (Western Java) using mutton and sheep offal that was a favorite of some Bantenese sultans and considered an intangible cultural heritage of the Bantenese Islamic Sultanate (1527–1813) (Table 1, Fig. 1F) [3, 41]. Rabeg resembles the Yemeni-style goat curry, which demonstrates an Arab-Islamic influence on Bantenese cuisine [41]. Another example is opor ayam (Javanese-style chicken curry), created by the Wali Sanga (the nine Islamic saints) using chicken (sometimes added with liver and gizzard) and served with ketupat (rice cake), which was used for Islamic preaching (dakwah) during Java’s Islamization period (around 15–sixteenth century) (Table 1) [46]. Furthermore, Java’s adaptation of curry-like dishes and its initial use of coconut milk have been historically documented in a famous chronicle called Serat Centhini, which was written in the Islamic Mataram Sultanate era (1586–1755) [74].

Since the thirteenth century, Chinese people have also migrated in waves to the Indonesian archipelago and established colonies (Pecinan, or Chinatowns) in some Indonesian regions, which play an indispensable role in the spread of Chinese culture, including Chinese cuisine, in the country [54]. Some Chinese delicacies were exclusively developed in Indonesian Chinatowns, such as chasio Medan (braised pork, which originated in Medan, North Sumatra), sekba (braised pork and pig offal, which originated in the Glodok district, Jakarta), and kwe cap (pig skin stew, which originated in Singkawang, West Kalimantan), involving the use of pig offal (Table 1) [28, 42, 54, 55]. According to Chinese culinary wisdom, all parts of an ingredient (including offal) must be entirely utilized to minimize wastage [54]. In Indonesia, the Chinese culinary tradition was gradually absorbed and assimilated along with local and other foreign cuisines, inspiring the creation of various fusion dishes (Peranakan cuisine) [54]. The creation of soto (soup), for instance, is a proof of the influence of Chinese culinary tradition on Indonesian cuisine. The word “soto” comes from the Chinese words “shao” (which means cooking) and “du” (which means beef or offal), signifying that soto was initially made with cattle offal [75]. The quintessence of old version of soto can still be discovered in some modern soto, such as soto babat-iso (tripe and intestine soto) and soto sulung (Madurese-styled offal soto) [56, 75]. Furthermore, soto Medan is a Chinese rice vermicelli-based soup combined with spicy coconut milk-based curry broth and halal meat (sometimes incorporating halal offal along with the meat), demonstrating a fusion cuisine (Table 1) [75]. Moreover, in Pekalongan, a town in Central Java, tauco (Chinese fermented soybean paste) is incorporated into a spicy water buffalo meat and offal soup, creating a specialty known as tauto Pekalongan (Table 1) [46, 54, 75]. The Chinese population also introduced a stir-frying technique that involves cooking in a pan with a small amount of oil. This cooking technique has inspired the locals of Semarang in Central Java to develop a specialty made of cattle tripe called babat gongso (stir-fried cattle tripe) (Table 1, Fig. 1G) [46, 54].

In the late sixteenth century, new ingredients from Central America such as cassava, chili pepper, peanut, and vanilla were introduced by European merchants (particularly by Spanish and Portuguese merchants), making Indonesian cuisine more vibrant [54, 76]. The addition of chili pepper has increased the level of spiciness of local dishes such as rendang, gulai, and kalio, encouraging people to eat more [20, 21]. Moreover, the presence of chili pepper in Indonesia has inspired the creation of various recipes of sambal (chili paste), such as sambal goreng ati-ampela (liver and gizzard stewed in chili sauce) from Central Java and sambal krecek (cattle skin in spicy sauce) from Yogyakarta, which were probably created in the Mataram Sultanate era (1586–1755) and are still served during local feasts such as selametan in Java (Table 1) [4, 51, 58, 70, 77].

Furthermore, the arrival of peanuts has also contributed to enrich the variation of Indonesian cuisine. In the late sixteenth century, a nutty-flavored soup called coto Makassar (Makassar-style beef soup) was created from a mixture of beef and cattle offal (tripe, intestine, tendon) stewed in a peanut milk-based curry broth (Table 1, Fig. 1H) [66]. It is usually served with burasa (rice cake) [66]. Initially, the dish used to be served as breakfast for the soldiers of the Gowa Sultanate in South Sulawesi [66]. This homogenous fusion of soto (Chinese-style soup), Indian curry, peanut (a foreign ingredient), halal meat and offal, and local seasonings in the form of a scrumptious dish demonstrates that Makassar (the capital of the Gowa Sultanate) was a busy area and a junction of various cultures at that time [66].

The Dutch colonists also brought their culture, including their culinary traditions, to Indonesia, which was later absorbed and assimilated with the local culture [78, 79]. Here, the European-style meat soups were adopted by the natives using local ingredients and seasonings [54]. Unfortunately, in the colonial period, meat was only affordable to and enjoyed by the Dutch, Indos (people of mixed ethnicity due to the intermarriage between locals and Europeans), and native aristocratic families [78,79,80]. On the other hand, the common native inhabitants were mostly destitute and could not afford meat. Therefore, they creatively developed a European-style soup made of the tail, bone, and bone marrow of cattle known as sop buntut (oxtail soup) (Table 1) [54]. A similar economic reason is also experienced in the creation of soto Betawi (Betawi soto), soto tangkar (cattle bone and trotter soto), and sop kaki kambing (goat trotter soup), for which offal of cattle and goat (including intestine, tripe, liver, trotters, bone, and bone marrow) was innovatively exploited by the proletarians in Batavia (now Jakarta) during the colonial times, as the price of fine meat was quite exorbitant (Table 1) [9, 80].

Historically, offal also became a traditional salary system for butchers [66]. The owners of an animal would usually pay a butcher with offal as wage after obtaining the meat [66]. For instance, in South Sulawesi, these activities inspired the birth of pallubasa (coconut milk-based offal soup), in which the offal obtained as a salary after butchering (tawana papolonga) was cooked in a spicy coconut milk-based broth (Table 1) [66]. This delicious dish was subsequently enjoyed by the working class as a low-price food, as offal was an economical and affordable ingredient in that time [66]. Pallubasa differs from its coto Makassar counterpart due to its utilization of coconut milk instead of peanut milk [66].

After the independence of Indonesia in 1945, comprehensive efforts were made to strengthen the country’s sense of nationality and unity [1]. One such effort was the creation of a new dish to inspire brotherhood among people. In South Sulawesi in the 1950s, an offal-based soup called sop sodara (which means “the brotherly soup”) was developed by a famous culinary entrepreneur using cattle offal (tendon, tripe, intestine, and lung) (Table 1) [66, 81]. The name for the dish was chosen in order to improve the brotherhood among the diverse people in South Sulawesi in the post-independence era [66, 81].

The creation of Indonesian OBDs is a continuous process that is going on even today. Nowadays, offal is often added as a topping into some modern Indonesian dishes not only because it is an economical ingredient for food traders that allows them to minimize their operational costs, but also because it offers a sense of abundance that attracts the attention of Indonesian millennials [82, 83]. For example, Indonesian’s legendary and ubiquitous bakso (meatball) is often served with an abundance of offal toppings (including liver, intestine, tripe, head skin, tongue, tendon, bone, bone marrow, trotter, lip, and even eyes of cattle), a combination that is famously known as bakso jeroan (meatballs with offal topping) (Table 1, Fig. 1I) [82]. Moreover, Indonesian millennials are also keen to consume spicy dishes because spiciness is believed to have a therapeutic effect that can relieve stress and help the mind as well as the body relaxed after routine activities [84]. A spicy street food that is enjoyed by millennials is ceker mercon, which is made of chicken legs stewed in a hot chili pepper sauce (Table 1). This millennial dish was possibly inspired by the traditional oseng-oseng mercon (spicy stir-fried tendon and head skin), in which cattle tendon and head skin are stir-fried and then cooked in a chili pepper sauce [51]. Here, the term “mercon,” which is a Javanese word for “the firecracker,” is used in the name of such dishes to hyperbolically illustrate the level of spiciness of the dishes [51]. In addition, these delicacies are not only a favorite of the working class but also of the higher class, which includes celebrities, aristocrats, and artists [85]. This suggests that there has been a cultural shift that valorize the value of offal in modern Indonesia [9]. Furthermore, the valorization of offal is not only experienced in the modern OBDs, but views on the traditional OBDs have also gradually been changed in which se’i lidah sapi (smoked cattle tongue) and gulai tunjang (tendon and head skin curry) are more expensive than meat-based dishes like se’i daging sapi (smoked beef) and rendang daging (beef rendang), respectively [9, 86, 87]. Even, in many Minangkabau restaurants, OBDs such as gulai tunjang, gulai otak, gulai tambusu and such are usually displayed in a separated plate which can further improve the feeling of exclusiveness and luxury [21, 88]. Thus, those exhibit that OBDs are currently a laudatory food that are more appreciated by Indonesians rather than previous periods.

The distribution of Indonesian offal-based dishes

This section recapitulates Indonesian OBDs (139 dishes) from all regions of Indonesia based on their origin, offal source, type of offal, and offal utilization in dishes (Table 1). In terms of origin, OBDs are geographically distributed in 23 provinces in Indonesia, where the diversity of these foods varies in each province (Table 1; Fig. 2). Most OBDs are centralized in West Sumatra, Central Java, and East Java, each of which has contributed with 31, 18, and 14 dishes, respectively (Table 1; Figs. 2 and 3A). Meanwhile, OBDs are extremely rare on the eastern coast of Sumatra, Kalimantan, parts of Sulawesi, and the Eastern Indonesian provinces (Table 1; Fig. 2). Moreover, OBDs are obviously absent in Moluccan and Papuan provinces in eastern Indonesia (Fig. 2). The only OBDs coming from eastern Indonesia is a smoked delicacy from East Nusa Tenggara, se’i (smoked meat), in which tripe, lung, intestine, and tongue of cattle and pig are sometimes added into the smoking process (Table 1; Fig. 2). It has been suggested that the diversity of OBDs in different regions in Indonesia is shaped by several factors such as culture, history, and natural resources [5, 20, 46, 52]. West Sumatra, Central Java, and East Java have strong cultural, historical, and gastronomical backgrounds associated with offal [20, 46, 52]. Furthermore, there are numerous animal husbandries established in those areas (West Sumatra, Central Java, and East Java) which not only produce animal products (meat, egg, milk and etc.) but also wastes (one of which is offal) [5]. The lower level of diversity in some areas of Indonesia (e.g., the eastern provinces of Sumatra, Kalimantan, parts of Sulawesi, and eastern Indonesia) is also caused by a tendency of using freshwater fish and seafood in dishes, which produces a less quantity of offal compared to the offal produced by domesticated livestock [3, 6]. In general, fish or seafood offal has traditionally been utilized as animal feed or fertilizer; therefore, the local dishes that use this ingredient do not vary [89]. The only examples of OBDs that incorporate fish/seafood offal are keripik telur cumi (squid ovary chip) from Bangka-Belitung, piritan from West Java, gulai telur ikan (fish ovary curry) from West Sumatra and a specialty from Kendal Regency of Central Java called pepes endog mimi (steamed horseshoe crab ovary and vegetables wrapped in banana leaf) (Table 1).

Fig. 2

The geographical distribution of Indonesian OBDs

Fig. 3

The geographical origin of OBDs (A); the use of offal in an OBD (B); the type of offal used in OBDs (C) and the source of offal (D). Meanwhile, the rest presents the geographical distribution of OBDs using cattle (E); water buffalo (F); pig (G); and chicken offal (H)

About 79 dishes utilize offal as the main ingredient, such as balado kikil (tendon and head skin spicy stew), soto kikil (tendon and head skin soup) and rica-rica hati ampela (chicken liver and gizzard spicy stew) (Table 1; Figs. 2 and 3B). Moreover, in 50 dishes, offal is incorporated to accompany the main ingredients (meat, rice, and vegetables), such as soto babi (Balinese pork soup), nasi krawu (rice with braised offal), and gulai kambing Aceh (Acehnese-style mutton curry) (Table 1; Figs. 2 and B). Sometimes, offal is also alternatively used as a substitute for meat, as discovered in 10 dishes, some of which are sate ampet (Ampet satay), krengsengan (stir-fried chicken stew), and satay ayam-ayaman (watercock satay) (Table 1; Figs. 2 and 3B). The priority of utilizing offal in a dish is determined by factors such as organoleptic and ethno-gastronomical backgrounds [3].

The intestine, liver, and tripe are the most commonly used offal in Indonesia, as discovered in more than 40 dishes (Table 1; Fig. 3C). This is due to an abundant volume of these organs (which amounts to about 20–25% of the animals’ weight) collected after slaughtering, which encourages people to process them into foods instead of dumping them as waste [6, 7]. Meanwhile, offal such as tendon, head skin, gizzard, bone, lung, and bone marrow are moderately used in over 10 dishes (Table 1; Fig. 3C). Another kind of offal is the blood, which is enormously incorporated in seven dishes that originated from Indonesian non-Muslim regions such as Bali, the Bataknese region of North Sumatra, and etc. (Table 1; Figs. 2 and 3C).

Cattle offal is the most utilized offal source, as discovered in 81 dishes, followed by water buffalo and chicken offal (used in 36 and 24 dishes, respectively) (Table 1; Fig. 3D). The dishes are distributed in West Sumatra, Java Island (chiefly in Yogyakarta as well as East, Central, and West Java) and the Bugisnese region of South Sulawesi (Table 1; Figs. 2, 3D–H). The presence of a majority Muslim population in those areas is the main reason why those ingredients are employed [2]. Meanwhile, the non-halal offal (obtained from pigs and dogs) is used in some of the dishes discovered in provinces where the non-Muslim population is quite significant, such as in Bali (8 dishes), Tapanuli or Bataknese region of North Sumatra (5 dishes), Singkawang region of West Kalimantan (2 dishes), Minahasan region of North Sulawesi (3 dishes), and Torajan region of South Sulawesi (2 dishes) (Table 1; Fig. 2, 3D, G) [2].

Additional file: 1 elaborates on the employment of spices, herbs, and other ingredients in offal cooking. Spices and herbs maintain the organoleptic aspect of OBDs, thereby further improving their deliciousness (Additional file: 1) [90]. Meanwhile, the preparations of offal and Indonesian OBDs are comprehensively elucidated and tabulated in Additional file: 2. The utilization of coconut milk is mostly discovered in OBDs of Sumatra (mainly in West Sumatra), parts of Java and Sulawesi, demonstrating the influence of Indian culinary tradition (Fig. 2 and Additional file: 1) [20, 21]. The addition of coconut milk in the OBDs can organoleptically enhance the savoriness of the dishes [20, 21]. Moreover, the addition of sesame oil, fermented soy products (i.e., soy sauce and soy paste), and shrimp paste into OBDs demonstrates the influence of Chinese culinary tradition, as discovered in parts of Java (including some Chinatowns in Java), the Singkawang region of West Kalimantan, and eastern Sumatra (the Medan region of North Sumatra, Bangka-Belitung, Riau Islands) (Fig. 2 and Additional file: 1) [54]. The addition of those ingredients in OBDs improves the umami flavor along with the other qualities such as saltiness, sourness, and sweetness, making these dishes more vibrant and scrumptious [54]. The Chinese culinary influence is also evident in the utilization of noodles and meatballs as discovered in some OBDs discovered in West Java (soto mi Bogor, or Bogor noodle soup) and Central Java (bakso balungan, or meatballs with bone marrow), as well as in ubiquitous dishes such as bakso jerohan and mie ayam ceker (chicken noodles with chicken leg topping) (Table 1, Fig. 2 and Additional file: 1) [54]. Furthermore, the influence of colonial culinary heritage in offal cooking is discovered in some soup-based dishes such as brenebon (pork/pig offal and red bean soup) in North Sulawesi and the ubiquitous sop buntut (Table 1, Fig. 2 and Additional file: 1) [54, 78]. Additionally, OBDs such as Saksang from the Bataknese region of North Sumatra and pa’piong babi (vegetables and pork/offal cooked inside bamboo) from the Torajan region of South Sulawesi tend to retain the native features of the Austronesian culinary tradition. Moreover, the trace of Columbian exchange in offal processing can be discovered in some dishes utilizing chili peppers and peanuts (Additional file: 1). Interestingly, chili pepper (Capsicum annum) is almost always used in Indonesian OBDs (Additional file: 1). The widespread utilization of this ingredient was due to the massive cultivation of chili pepper in the past after it arrived from Meso-America [4, 76]. Capsaicin not only improves the spiciness of OBDs but can also omit the unpleasant aroma of offal [4]. The use of another imported ingredient, peanuts (Arachis hypogaea), in the form of peanut paste or peanut milk, is discovered in pecel tumpang (Javanese-style salad with lung jerky topping) from East Java and coto Makassar from South Sulawesi, respectively (Table 1, Fig. 2 and Additional file: 1). The use of peanut milk in coto Makassar creates a particular flavor that tastes as savory as coconut milk [66].

Conclusions

To summarize, Indonesian OBDs are a cultural heritage and intangible national asset which have been created and influenced by various factors such as natural resources, history, religio-cultural and economic backgrounds. In this archipelagic country, authentic recipes of OBDs vary greatly across regions, defining the diversity. Although OBDs (139 dishes) are widely distributed in 23 provinces of Indonesia, most of these dishes are concentrated in West Sumatra (31 dishes), Central Java (18 dishes), and East Java (14 dishes). The intestine, liver, and tripe are the most commonly utilized offal as they are utilized in over 40 dishes; while tendon, head skin, gizzard, bone, lung, and bone marrow are the second favorite. Moreover, cattle, water buffalo, and chicken are the most utilized sources of offal. Meanwhile, pig offal is only used and distributed in non-Muslim regions of Indonesia. On the one hand, the creation of Indonesian OBDs is influenced by foreign cultures, such as Indian, Arabian, Chinese, and Dutch-Colonial culinary traditions, while on the other hand, some OBDs retain the native features of Indonesian culinary tradition. Furthermore, the utilization of indigenous spices and herbs maintains the organoleptic attributes of OBDs. Additionally, foreign ingredients such as peanuts and chili peppers are discovered in several OBDs, demonstrating the trace of Columbian culinary exchange (Additional file: 3).

Recommendations

This article is the first academic article in the world discussing on Indonesia OBDs. Thus, the manuscript can hopefully inspire people working in the related areas (food science, ethno-culinary science, gastronomy, and cultural science) to propose any researches related to Indonesian OBDs. Authors vehemently suggest to conduct any future studies related to a particular Indonesia OBD and its business aspect which can potentially enrich the national and international ethno-culinary databases. Furthermore, authors also open opportunities of any future research collaborations in that area. Moreover, authors suggest the government of the Republic of Indonesia and also UNESCO to conserve and register the Indonesian OBDs as the intangible world heritage. The government of the Republic of Indonesia should also introduce as early as possible these Indonesian OBDs through the national educational curriculum in Indonesian schools (through some subjects such as Biology, Geography, and Sociology) and include them as a part of National food security agenda.