Local Tubers Production and Value Chain: Evidence from Sangihe Island Regency, Indonesia

Abstract

Sangihe Islands Regency is an archipelago located in the border area of the Philippines. The area is far from the Provincial Capital and the Indonesian capital of Jakarta. Therefore, it is sometimes difficult for people to access basic needs, especially food. On the other hand, they have access to alternative food consumed hereditary. For instance, there are plenty of tuber food crops, including cassava, sweet potatoes, and taro. Thus, there is a need for discussion in empowering people on the benefits of tubers such as productions, value chain, and potential development. The methodological approach used is descriptive exploratory, where the data collected is secondary from the desk review related to the potential and food conditions of the people in the area. Several local tuber crops are suitable for development as a staplefood on Sangihe Islands. The development supported by the adequate technological application can optimally increase product value and revenue. Furthermore, those aspects need systematically and synergistically patterned.

1. Introduction

The issue of food security has been developing for a while, both in the international community and in the national community in Indonesia. In several processes and forms of national food security, the government promotes local food-based community development [1, 2]. Alternative ideas for realizing national food security are not only important but should become a massive national movement to guarantee people’s quality of life at the local, national and international levels. Food security is not only the problem of producing rice or other crops to be consumed as they are. However, in a broad sense, food security includes how society at local and national levels can produce other crops than rice such as corn, tubers, cassava, sago, and so forth. At the local level, the production depends on the area where the community resides [1, 3].

Communities on the border areas, whose territories are archipelagic areas, are vulnerable to food insecurity. The availability of food on the border with wider natural conditions, and the sea area makes this place highly dependent on food supplies from outside the region. The availability of food in the regions must be optimized to meet food needs. Utilization of the potential local food crops will be important in efforts to meet food needs so that the community will be in a food security position.

Some of the main developing issues are related to food security in border areas, including socio-economic inequality between people living in border areas and neighboring countries, relatively low agricultural productivity, limited information and technology dissemination, inadequate infrastructure, availability of infrastructure and facilities, distribution of land and between islands that can reach all regions. Thus, the inability of the poor to provide sufficient food in terms of nutrition and food security has not become a major concern [4, 5].

An important aspect in achieving food security for people at the border area is the ability to empower local food sources. To anticipate this, it is necessary to bring back local food sources [6]. States that local food has advantages in terms of quality, quantity and also functions for the preservation of biodiversity. The border area of the Sangihe Islands Regency has several types of local food such as tubers which are sources of staple food for the area.

The way to build food self-sufficiency in small islands and border areas is very wide open because the people in the area have been familiar with non-rice food sources for decades and the area does have local food sources that can substitute rice [7]. The increase in food production capacity is carried out based on the potential of agricultural resources. The development of food production is not based on a specific commodity approach, but rather on potential commodities in each region that can be developed into local food sources by increasing production and product processing [8]. Regarding the development of tuber production as local food in border areas, the current condition tends to decrease both in terms of cultivation and utilization of the product due to the declining preference for local food and the lack of intervention in preservation [9]. Local food management in border areas is still limited to traditional techniques and products are not managed with an optimal farming system. To manage local food resources, technological innovation is needed, starting from the cultivation stage to the processing stage to ensure the availability of raw materials for processed food.

Technological innovation for the use of local food needs to be directed at increasing added value, competitiveness, and improving production technology to produce products that are following the wishes and needs of the community (demand-driven) [10]. The increase in added value and product competitiveness is the difference between the potential selling value of the product and the costs required for production. The added value and competitiveness of the product can attract investors to participate in developing the local food agroindustry. Improvements in local food technology, among others, are directed at producing products that are easy and practical to process and consume, with taste and quality that are following market demands. The products should also taste good and be packaged attractively, as well as easy to access (continuity of product availability). The technology developed should be adapted to the needs of the community and the growing market, so that it can compete with other products. Technological improvements will provide opportunities for the realization of product diversity that provides opportunities for consumers to choose products that truly suit their needs and preferences [11, 12].

This paper presents the potential, problems, support for technological innovation, added value, and strategies for developing local tuber food in the border area of the Sangihe Islands Regency.

2. Methodological approach

The present research design is the scientific review method. This method is used to conduct descriptive exploration and data analysis regarding the topics discussed, which are sourced from various scientific references, both from research reports and relevant journals.

3. General conditions of the border area

3.1 Regional characteristics

The Sangihe Islands Regency, located in North Sulawesi Province, is a region in Indonesia that is directly adjacent to the neighboring Philippines (Article VII of Law No. 77 of 1957). This area is the gateway and northern fortress of the Unitary State of the Republic of Indonesia and is a cross-border trade area (Article II of Presidential Decree No. 6 of 1975). In developing the management of islands in border areas throughout Indonesia, where priority is directed to agricultural development planning for certain commodities according to the carrying capacity of the island, the agricultural sector is the main source in meeting basic life needs, especially food, and plays an important role in the economy of the region.

The Sangihe Islands Regency is geographically an integral part of North Sulawesi Province with Tahuna as the capital. It is about 142 nautical miles from the Capital of North Sulawesi Province, Manado, located between 20 4′13″–40 44′22″ North Latitude and 1250 9′28″–1250 56′ 57″ East Longitude. Its boundaries are as follows: North-Republic of the Philippines and the District of the Talaud Islands; South-Sitaro Regency; East—the Pacific Ocean and Maluku Sea; West-North Sulawesi (Figure 1). The area is 736.98 km² divided into 15 sub-districts (Figure 2). North Tabukan is the sub-district with the largest area, about 114.76 km² (15.57% of the total area of the Sangihe Islands Regency).

Figure 1.

Regional Map of Sangihe Islands Regency.

Figure 2.

Sangihe Islands Regency by District year 2016 [13].

In general, the average monthly air temperature at the 2016 Naha Meteorological Station measurements is 27.8°C, where the lowest air temperature is 20.0°C (in March), and the highest air temperature is 34.0°C (in July). Rainfall in a place is influenced by climatic conditions, geographical conditions, and the rotation or meeting of air currents. Therefore, precipitation varies monthly. The highest rainfall in 2016 occurred in November, namely 465 mm³ with 24 rainy days, while the lowest rainfall occurred in March, which was 40 mm³ with 16 rainy days.

The population of the Sangihe Islands Regency in 2016, based on the population projection, was 130,024 people with 34,040 households and a population density of 176.43 people/km². North Tabukan Subdistrict is the most populated with namely 15.15% of the total population in Sangihe. Also, the highest population density is in Tahuna District as the capital of the Sangihe Islands Regency, which is 717.39 people per square kilometer.

3.2 Agricultural characteristics

The condition of the land in the border area of the Sangihe Islands Regency is included in the Dry Land Agroecosystem Zone. In fulfilling rice needs, the area must rely on supplies from outside the region, both from the Regency and Province. Generally, cultivation lands in border areas are used for root crops such as sweet potatoes, cassava, and taro (local tubers specific to the location). The specific condition in this border area is the presence of a local tuber/taro plant called the dalugatuber. The tuber is a type of taro tuber that belongs to the Xanthosomasp family, grows wild in swampy areas, and is used by the community as a food reserve.

Horticultural crops, especially vegetables such as chili, tomatoes, eggplant, are cultivated at a household scale through home gardens. This is also true for fruits. Mango, pineapple, banana and orange, coconut, nutmeg, and cloves are the most widely cultivated plantation crops by farmers and are spread throughout the border areas. The use of coconut by farmers is only limited to making copra and household needs.

4. Potential development of local tubers

4.1 Varieties of local tubers

Local tubers, as sources of non-rice carbohydrates, are specific food crops for people in border areas, with the potential to be developed as alternative food ingredients to support food security. There are several types of local tubers in the North Sulawesi Province, especially those in the border area of the Sangihe Islands Regency. Types of local tubers are cassava, sweet potato, and taro. These tubers are spread over 15 sub-districts. Production potential recorded in 2016 was for cassava with a harvested area of 302.5 ha, production of 1,210 tons; sweet potato with a harvested area of 186 ha and production of 806 tons and taro with a harvested area of 213.5 ha and production of 759 tons. South Tabukan Sub-district is the largest contributor to production, with around 49.92% [14].

4.1.1 Cassava (Manihotutilissima)

Cassava (Manihotutilissima) is a tropical and subtropical plant of the Euphorbiaceae family. It has a taproot and some branch roots that enlarge into root tubers. It is considered an adaptable plant that grows in various tropical agro-climates and does not demand a specific climate in its growth [15]. It was also stated by [16], that “cassava is a wind-resistant plant and will thrive under conditions of low soil fertility”. This type of plant can grow in any place, especially in the tropics with full sun throughout the year, and has high adaptability to various soil conditions. [17] stated that cassava production centers are usually located on dry land on alkaline soil and acid soil which are poor in organic matter and macro and micronutrients with weed disturbances. Because the cassava plant has wide adaptability, it can live and produce on land under these conditions. This aspect is due to the nature of the cassava plant which is very efficient at absorbing nutrients in the soil.

According to the Center for Agricultural Information and Information Systems [18], cassava is a substitute for rice with an important role in supporting the food security of a region. It has a fairly complete nutritional content. The chemical and nutritional contents of cassava are carbohydrates, fat, protein, dietary fiber, vitamins (B1, C), minerals (Fe, F, Ca), non-nutritive substances, and water. Besides, cassava contains non-nutritive tannin compounds [19]. Furthermore, [20] stated that cassava has a fairly good nutritional value and is indispensable for maintaining a healthy body, as food, especially as a source of carbohydrates, but poor in protein. The nutritional content of cassava can be seen inTable 1.

Component	White Cassava	Yellow Cassava
Energy (Cal)	146	157
Protein (g)	1.20	0.80
Fat (g)	0.30	0.30
Carbohydrates (g)	34.70	37.90
Ca (mg)	33.00	33.00
P (mg)	40.00	40.00
Fe (g)	0	0.70
Vitamin A (SI)	0.70	386
Vitamin B1 (mg)	0.06	0.06
Vitamin C (mg)	30	30
Water (g)	62.50	60
Edible part (g)	75	75

Table 1.

Chemical composition of cassava per 100 g.

Source: [19].

Cassava, as a source of carbohydrates, can be used as animal feed and industrial raw materials. Therefore, the development of cassava is crucial in efforts to provide non-rice carbohydrate foods, diversify local food consumption, develop product processing and agro-industries as well a source of foreign exchange through exports and efforts to support increased food security and food independence. Although cassava is a source of carbohydrates, the yield of the plant at present is not optimal. Cassava is usually only boiled, fried, or processed into chips. Various variations of food can be produced from cassava. Cassava flour can be used to replace wheat flour.

4.1.2 Sweet potato (Ipomoea batatasL.)

Sweet potato has great potential as an alternative food. It is quite popular in Indonesian society, especially in the eastern region, which uses sweet potato as a staple food. Sweet potatoes are a very healthy and very good food ingredient. This condition is because sweet potatoes have a high nutritional content of complex carbohydrates, thus, leading to a gradual energy release. Among staple foods, white sweet potato contains the highest calcium compared to rice, corn, wheat, and sorghum. The calcium content can reach 51 mg/100 grams for yellow sweet potatoes [21] (Table 2).

Composition	Content/100 grams
	Rice	Corn	Wheat	Sorghum	Sweet potato
Calories (cal)	360	361	365	332	152
Protein (g)	6.8	8.7	8.9	11.0	1.5
Fat (g)	0.7	4.5	1.3	3.3	0.3
Carbohydrates (g)	78.9	72.4	77.3	73.0	35.7
Calcium (mg)	6.0	9.0	16.0	28.0	29
Iron (mg)	1.0	5.0	1.0	4.0	0.8
Phosphorus (mg)	140	380	106	287	64
Vitamin B1 (mg)	0.12	0.27	0.12	0.38	0.17

Table 2.

List of food ingredients per 100 grams.

Source: [21].

Apart from being a source of carbohydrates, the potential of sweet potatoes in the context of diversifying staple foods from local resources is very good. The low price of sweet potato and its affordability at all levels of society is a major factor to encourage business diversification of staple foods other than rice. Sweet potato is a local source of carbohydrates that is used for its root tubers. In Indonesia, sweet potatoes are used as raw material for flour, instant rice, bakpia, donuts, chips, noodles, and pearl rice. Sweet potato flour can be processed into various food products similar to foods made from wheat flour, such as candy, ice cream, bread, cakes, and some soft drinks.

The development of sweet potatoes for various processed products is very perspective because, in addition to the multi-use nature of sweet potatoes, the technology for processing agricultural products is quite advanced in Indonesia. With processing technology, sweet potatoes can be processed into various products such as chips, starch, flour, sauce, jam, chips, croquettes, tape, kremes, brem, getuk, pilus, fried sweet potatoes, boiled sweet potatoes, and sweet potatoes. In the form of processed products, sweet potatoes can be upgraded to the equivalent of rice. Sweet potato is also a raw material for the food and non-food industry which is more successful. The success of the food diversification program will reduce dependence on imported rice [22].

4.1.3 Taro (ColocasiaesculentaL)

Taro is a year-round plant. It can grow in various areas, both natural and farmed. This plant, widely grown in rural areas, is usually used as a food substitute for rice, snacks, and even just allowed to grow [23]. In the border area of the Sangihe Islands Regency, there are two types of local taro specific to the location, namely Daluga tubers, and Kole Rea tubers. These two taro tubers are used by some people as a staple food to replace rice.

4.1.1.1 Daluga tubers

Daluga tubers are included in the taro tuber group in the Araceae family. This tuber is a commodity that has important prospects and has high economic value compared to other types of tubers such as sweet potatoes and cassava. Taro is an important food source because the tubers are foodstuffs that have good nutritional values. Daluga tubers can be harvested after about 10 months to 3 years. Bulb weight is quite high, on average 2–5 kg per tuber. Daluga lives well in places that are quite watery such as riverbanks or marshy land and are somewhat protected from the sun. Daluga reproduces by seeds or vegetative [24]. In some border areas, the potential of this tuber is quite promising, but rice is increasingly known to the public. This tuber is no longer cultivated, only planted wildly and not maintained. The highest nutrient content in taro is starch, although it varies between types of taro. Besides being used as a source of carbohydrates, taro tubers can also be used as a functional food because of their high oligosaccharide content [25]. Ref. [26] stated that, when viewed from the nutritional content, taro tubers are considered healthy food commodities and the level of safety lies in their low carbohydrate content (22.25%), reduced sugar (0.87%), and starch content (24, 25%, 11%). The results of the study [9] showed that daluga tuber contains a fairly high carbohydrate with 32.53%, and the flour contains fat of about 23.32% and starch content of 48.86% (Table 3).

Parameter	Daluga bulbs	Daluga flour
Water	63.86	1.11
Protein	0.64	1.97
Fat	1.43	23.32
Carbohydrates	32.53	48.86 (starch)

Table 3.

Nutrient content of tubers and daluga flour.

Source: [9].

4.1.1.2 Cole Rea Bulbs

This type of taro for the people on the border of Sangihe is known as kolerea which means looking for sweet potatoes. It has white tubers. The border area of this population is large compared to daluga tubers. In addition to taro kolerea, there is also taro with purple leaf stalks known as bete retraction. The level of community consumption of taro colerea is still high because of the easiness of cultivation and maintenance. Thus, some community members cultivate this taro intensively in the yard and the garden. This plant is intensively cultivated by paying attention to the nursery and its maintenance.

4.2 Basic food commodities

The results of a study conducted by [27], concerning Location Quotient (LO) analysis, reported that the food crop in the agricultural sector, especially local tubers (cassava and sweet potato) in the border area of Sangihe Islands Regency, had a location quotient (LQ) value >1. Cassava has a value of 9.1, while sweet potato has a value of 12.64 (Table 4). With these values, the food crop commodity can meet the needs in the border area of the Sangihe Islands Regency and is expected to encourage the growth of other economic sectors so that it can increase the economic growth rate of the region.

Commodity	Districts Sangihe Islands	Province North Sulawesi	Location Quotient (LQ)
	Production (ton)	Production (ton)
Cassava	9766.70	279.22	9.1
Sweet potato	9441.87	192.43	12.64
Total	22,456.79	5,785.66

Table 4.

Location quotient (LQ) production of food crops (local tubers) level districts.

Source: [27].

Location Quotient (LO) analysis, at the sub-district level in the border area of the Sangihe Islands Regency, shows the LQ value of >1 for cassava spread over several sub-districts, with LQ values of 1.39 in South Central Tabukan, 1, 06 in South Southeast Tabukan,1.39 in central Tabukan, 1.4 in Manganitu, 1.05 in West Tabukan, 1.18 in North Tabukan and 1.03 in Kendahe. For sweet potato commodities, the LQ values were as follows: South Tabukan District had 1.45, South Central Tabukan with 2.09, South Southeast Tabukan with 1.11, Central Tabukan with 2.09, Manganese with 2.11, Tahuna with 1.04, East Tahuna with 1.72, West Year with 1.58, North Tabukan with 1.77 and Kendahe with 1.73. The value of taro commodity in South Manganitu District was 1.56, 2.29 in Tatoaren, 1.26 in Tamako, 1.09 in South Tabukan, 2.21 in Central Tabukan, 1.14 in Tahuna and 1.31 in Tahuna Timur (Table 5). This result shows that the yields of the three food crop commodities (cassava, sweet potato, and taro) make them the basic commodities that can meet the needs in the border areas of the Sangihe Islands Regency.

Number	Districts	Commodity
		Cassava		Sweet potato		Taro
		Production (ton)	LQ	Production (ton)	LQ	Production (ton)	LQ
1	Manginitu Selatan	42	0.86	22.5	0.69	48	1.56
2	Tatoaren	12	0.86	—	—	20	2.29
3	Tamako	16	0.93	45	0.59	32	1.26
4	Tabukan Selatan	604	0.97	400.5	1.45	428	1.09
5	Tabukan Selatan Tengah	72	1.39	22.5	2.09	24	0.74
6	Tabukan Selatan Tenggara	52	1.06	36	1.11	24	0.78
7	Tabukan Tengah	44	1.39	4.5	2.09	24	2.21
8	Manganitu	108	1.4	45	2.1	24	0,5
9	Tahuna	28	0.69	36	1.04	29	1.14
10	TahunaTimur	28	0.57	8	1.72	29	1.31
11	Tahuna Barat	52	1.05	49.5	1.58	12	0.39
12	Tabukan Utara	112	1.18	85.5	1.77	20	0.34
13	Nusa Tabukan	—	—	9	0.54	48	3.08
14	Marore	4	1.15	2	0.86	2	0.91
15	Kendahe	36	1.03	40.5	1.73	4	0.18

Table 5.

Location quotient (LQ) production of food crops (local tubers) district level.

Source: Result of data analysis (2021).

The production of tubers recorded in 2016 was cassava, with a harvested area of 302.5 ha, and a production of 1,210 tons, followed by sweet potato harvested with an area of 186 ha and a production of 806 tons and taro with an area of 213.5 ha and a production of 759 tons. South TabukanSubdistrict was the largest contributor to production, which was around 49.92% [14]. This condition opens opportunities for its development and it is hoped that the farming system of the three commodities will encourage the growth of other economic sectors to increase the economic growth rate in border areas.

4.3 Value chain analysis of local bulb farming

The results of field observations of various tuber products in the border areas of the Sangihe Islands Regency showed that the economic value is still dominant only from primary products in the form of wet tubers, even though the economic value will be several times higher if there are additional productive activities in each channel such as large-scale product processing, economy, structuring the marketing system, as well as packaging processed tuber products [28] stated that this integration pattern between production and land productivity can be increased or farmers’ incomes can also increase and be more resistant to various risks, such as season, price, and income generation. By using the production data of tubers (cassava, sweet potato, and taro) in 2016 in the border area of the Sangihe Islands Regency in 2016, if only half of these primary products were to take a value chain approach with an added value of IDR 4500/kg, there would be an increase in production value of IDR 2.72 billion (cassava), IDR 1.81 billion (sweet potato) and 1.70 billion (taro) with a total value of IDR 6.20 billion. The income of farmers from tubers farming with primary products in the form of wet tubers is only around IDR 2000–IDR 3000/kg with potential productivity of 20 tons/harvest/ha so that a production value of around IDR 40 million–IDR 60 million with a net income of around IDR 20 million–IDR 30 million/ha/year. Through the value chain approach at the tuber farmer level as above, farmers will get an additional production value of approximately IDR 30 million–IDR 50 million/ha/year.

It is an indication that the current condition of the tuber product value is only in the form of wet tubers and it is necessary to immediately switch to other, more profitable products. The current condition of the products produced is still dominant for local needs. Efforts to increase income from tuber farming, the processing of tuber products are relevant options. The development of tuber farming in North Sulawesi Province, especially in border areas, is classified as crucial and has the opportunity for exportation.

Generally, tuber farmers sell their products only individually directly to collectors or consumers. This is an activity to shorten the marketing chain with a collective sales system. The difference in prices in the form of wet primary products from village/sub-district collectors with consumers or manufacturers is usually a price difference of around IDR 1000–IDR 2000/kg. For tuber products that have been processed (flour form), the difference will be even greater. If farmers in one village can produce 200 tons/year with a price difference of IDR 2000/kg, then farmers in the village have lost their income of IDR 400 million/village/year. Therefore, tubers farmers have the opportunity to generate additional collective income of around IDR 300 million–IDR 350 million/village/year. If the farmer has 20 tons of wet tubers, there is an opportunity for additional income per year of IDR 20 million–IDR 25 million/year.

5. Tuber plant technology and support innovation

Technological innovation plays an important role in agricultural development. Innovative technology is produced through research activities, both in the context of improving the existing technology (indigenous technology) and creating completely new technology. Some of the superior varieties of tubers that have been produced by the Agricultural Research and Development Agency are as shown in Tables 6 and 7.

Varieties	Productivity (ton/ha)	Harvest age (month)	Pest/disease resistance
Adira-1	22	7–10	Somewhat resistant to red mites; resistant to leaf blight, resistant to wilting
Adira-2	22	8–12	Fairly resistant to red mites; wither
Adira-4	35	10	Enough red mites
Malang-1	24.3–48.7	9–10	Fairly resistant to red mites, tolerant of leaf spot, wide adaptability
Malang-2	20–24	80–10	Slightly sensitive to red mites, tolerant of leaf spot and leaf blight
Darul Hidayah	10–21	8–12	Slightly sensitive to red mites and fungal rot
UJ-3	20–35	8–10	Resistant to leaf blight bacteria
UJ-5	25–38	9–10	Resistant to leaf blight bacteria
Malang-4	39.7	9	Somewhat resistant to red mites, adaptive to sub-optimal nutrients
Malang-6	36.41	9	Somewhat resistant to red mites, adaptive to sub-optimal nutrients

Table 6.

Description of several superior varieties of cassava by the research agency and agricultural development.

Sources: [29, 30, 31].

Varieties	Release year	Productivity (ton/ha)	Harvest age (month)	Characteristics
Muara Takus	1995	30–35	4.0–4.5	Resistant to scab/scab disease, good tuber shape, high tuber dry matter weight, suitable for planting in dry land and paddy fields
Cangkuang	1998	30–31	4.0–4.5	Somewhat resistant to lanas pests, resistant to scurvy, good shape of tubers, high dry matter weight of tubers, a high percentage of tuber weight, suitable for planting on dry land or rice fields after rice, which is not very fertile
Sewu	1998	28.5–30.0	4.0–4.5	Slightly resistant to lanas pests, resistant to scabies, good tuber shape, medium-dry matter weight, suitable for planting on dry land or rice fields after rice
Boko	2001	25–30	4–4.5	Moderately resistant to boleng/lanas/borers and resistant to leaf rollers, tolerant of scabies and leaf spot.
Sukuh	2001	25–30	4–4.5	Somewhat resistant to boleng/lanas/borers and leaf curlers, resistant to scabies and leaf spot
Jago	2001	25–30	4–4.5	Somewhat resistant to boleng/lanas/borers and leaf rollers, moderately resistant to scabies and leaf spot.
Kidal	2001	25–30	4–4.5	Slightly durable with holes/lanas/borers and leaf rollers, resistant to scurvy and leaf spot bercak

Table 7.

Description of several superior sweet potato varieties of agricultural research and development agency.

Sources: [29, 30, 31].

In Indonesia, tubers are used as raw materials for flour, instant rice, bakpia, donuts, chips, noodles, and pearl rice. Flour derived from tubers can be processed into a variety of food products similar to food ingredients made from wheat flour, such as sweets, ice cream, bread, cakes, and some soft drinks. Currently, the use of wheat flour as a substitute for wheat flour is not a new development. The development of root crops for various processed products is prospective, because of its multi-purpose nature. Taro tubers can be processed into various products with nutritional value. Products that can be produced from taro tubers can be grouped into categories that include the development of (1) products from fresh tubers, (2) intermediate products, (3) ready-to-cook products, and (4) ready-to-eat products of fresh tubers such as taro flour, taro chips, and traditional food products [32]. Flour processing is the best choice because: (1) flour is a product that is practical to use, so that it can be processed directly into instant food or as raw materials of other food products, (2) flour-processing technology is very easy to adopt and apply at low cost, so that small to medium-sized businesses can develop this business (3) flour easily fortified with the necessary nutrients such as vitamins and minerals and, (4) people have become accustomed to consuming food derived from flour. Derivative products of taro flour can be used as dodol, various wet and dry cakes, noodles, cheese sticks, bread, breakfast meal, analog rice, cookies or biscuits, and sauces [33]. From a fresh state, tubers can be processed into a variety of ready meals or snacks, dried sawut or gaplek, chips, starch, and tuber flour. Many ready meals are made from fresh tubers, such as pilus, cakes, croquettes, enyek-enyek, getuk, or various kinds of cakes [34].

Fresh Taro daluga can be processed into a variety of products including chips, dodol, brownies, dried mustard, noodles, and various other wet cakes. Dodol is one type of processed food that is classified as semi-wet food because it has a water content of 10–40% with a water activity of 0.65–0.90 it has an elastic and dense texture [33]. The product is easy to process and can increase added value and diversify the product. Tubers talas in the form of flour have better nutritional composition than rice. Taro flour contains higher protein and lower fat than rice. The fiber content of taro is also quite high and very good for maintaining the health of the digestive tract. Taro flour is classified as smooth and easy to digest. It is useful for the manufacture of pastries, cakes, bread, and noodles [35]. Processing of taro flour products is expected to minimize losses due to fresh taro tubers not being sold out when over-harvest production. Besides, taro flour can be used as a substitute for processed food products such as sweet bread [36]. The use of taro can increase the economic value in the form of flour and taro starch as well as the shelf life of taro production. Taro starch can be used as a new type of starch and an alternative companion or substitute for wheat. Processing taro tubers with taro flour raw materials is still limited because taro flour is not available on the market [37]. One stage of the flour-making process is drying, where the drying temperature affects swelling power,solubility, and myelography properties.

6. Local tuber development challenges and problems

Local food in the border area, especially the archipelago area, is different and has its characteristics compared to local food in non-island areas [38]. The challenges faced in the development of local tubers in the border area are based on potential analysis with the approach of border areas and value chains. Land use, the potential of existing land has not been utilized optimally. The land is generally dominated by dry land and some swamps, so there are constraints on development and utilization in trying to farm. Land capability implies land carrying capacity. Land capability is the quality of land that is assessed with the understanding of a compound identifier of land and the value of land capabilities is different for different uses. Concerning the fulfillment of human needs, the ability of land is described in the understanding of land carrying capacity [39].

The climate and weather conditions in the border region are erratic and often capricious. During the northern wind season, wind speeds can reach 40 mph with seas surges. These natural conditions result in residents or communities on the border experiencing shortages of foodstuffs. There are generally border areas included in the criteria of poor villages, with growth tending to be slower compared to the surrounding villages [40]. Some factors that cause the slow growth of villages in the border areas include (a) no thorough identification regarding the socio-economic potential of the people in the border area, essentially a supporting factor for the resilience of the people in the border area; (b) the weak ability of social and economic services of the people in the border area compared to the number of people to be served; and (c) the lack of evenly distributed social and economic services in the border areas seen based on location or spatial distribution; (d) lack of community motivation in improving the household economy through crop cultivation efforts.

Based on the Sangihe Islands, Human Development Index in 2014 was 66.82, lower than the average HDI of North Sulawesi that reached 69.96. This condition is partly seen from the low level of education of the population aged 15 years and above, who are only elementary school graduates (52%) [13]. People in the border region have a perception of the prospect of developing root crops (cassava, sweet potatoes, and taro), although the level of preference for rice is higher. The people of the city see it as the foodstuff of the weak economic class or rural communities. On the contrary, rural communities see it as a commodity of high social value, as it is usually served in traditional parties, such as weddings, chief appointments, welcoming guests, and death.

Generally, the management system of tuber farming in the border area of the Sangihe Islands regency is dominantly conventional. The factors that influence farmers’ decision to adopt technology are the direct benefit of technology in the form of relative benefits, conformity of technology to socio-cultural values, and ways and habits of farming [41]. The economic value of tuber farming products will be higher if every sub-part of the agribusiness system can carry out productive activities to create benefits and employment opportunities. To increase the income of tuber farming, the processing of tubers products becomes a relevant option. The root products also have the potential to become feed for livestock development. So far, the mainstay of the economic value of the tubers is still very dependent on the primary product [26].

Given the ownership of assets, the farming community is relatively small, individual actions in business development will be very difficult in reaching optimal benefits. Therefore, the development of business in the future that is of maximum added value needs to immediately take collective action in the sale of proceeds, purchase of production facilities, investment funds, and access to new technology information and business partners.

Some of the main problems that must be addressed in the development of local food value chains in the border areas include:

1. Inconsistent regulatory/policy support to improve commodity competitiveness.

2. Potential food insecurity and malnutrition for people in isolated areas.

3. Low productivity of local quality food.

4. Unavailable downstream industry players.

5. The potential of the local market has not been optimal so market access is still limited.

6. Still the low quality of human resources, weak institutional both at the level of the main actors and business support institutions in the value chain of tuber development.

7. Limited availability of field extension workers.

8. Weak coordination and partnership between government-private actors.

9. Availability of infrastructure that is not optimal.

The main factor that weakens agricultural businesses, including the development of tuber commodities, is that farmers’ economic institutions do not have strong intentions to build [42]. Stated that the lack of functioning as agricultural institutions were partial since the establishment of these institutions was not carried out in a participatory manner, where farmers as beneficiaries and placed as actors running these institutions.

7. Strategic steps in local tubers development

Facing an era of globalization and free competition, small agricultural-based industries need attention to increasing the added value of local food products as the economic center of communities in the border region. Strategic steps that can be taken in the development of local tubers to increase production and productivity in the border areas of Sangihe Regency include:

1. Improvement of regulations/policies that support the business climate and infrastructure:

   • Central government support through accelerated development program in the outer border areas of the island.

   • Banking support on credit base rate for businesses.

   • The policy of the Ministry of Agriculture to facilitate the certification of geographical indications as a form of protection of the authenticity of agricultural products of an area can have the opportunity to improve the competitiveness and marketing of food products and change public consumption patterns.

   • Allocating budgets for tasks and functions in the agricultural sector in the border region.

   • Increasing the motivation of farmers in cultivating local tubers.

   • Increased community preference for local tubers-based food.

   • Providing its main infrastructure access from all industrial centers to the city or market including improved transportation services.

   • Limiting the transfer of agricultural land to settlements or roads.

2. Institutional strengthening of organizations and supporting the development of local tubers:

   • Improvement of support agencies involved in the development of local tubers.

   • Improving the ability of farmers in carrying out cultivation technology and post-harvest handling and processing of yields.

   • Changing the mindset of farmers who are still oriented to meet the needs of their own families and have not been oriented to commercial businesses.

   • Increasing the number of agricultural extension workers so that farmers get information about the latest technology.

   • Providing processed industries and product packaging.

   • Grow organizations that can represent farmers or groups of actors in the value chain.

   • Involves the role of indigenous institutions in encouraging the cultivation of local tubers.

3. Development of patterns of cooperation and partnership between government-private and community.

   • The development of local tubers cannot be done individually, it must be done in an integrated manner, requiring the participation of businesses that understand the production process and market information.

   • Increasing the role of local governments in supporting problem-solving in farmers, collectors, traders, and processed industries.

   • Improving the role of society including increased knowledge/awareness and increased income.

   • Improved partnership. The implementation, synchronization, and cooperation between all stakeholders in the development of food consumption including the development of food processing technology.

   • Optimizing the system of coordination and partnership between supporting institutions due to the ego of sectoral interests.

4. Research, development, and innovation regarding cultivation technology and development of derivatives. Local tubers in the border area of Sangihe Islands regency have not been considered important commodities, while in some areas in Indonesia, they are used as food and non-food raw materials, such as noodles, fried cassava, dessert, confectionery, soy sauce, flour, wine, vinegar, nata de coco, and others. Even lately with a limited supply of energy sources, sweet potatoes are explored to be an updated alternative energy source, including converting sweet potatoes into bioethanol. Meanwhile, in the border area, exploration of the utilization of local tubers is still very far behind. The current condition of the majority of local tuber utilization is still limited to the main food sources only, so efforts to diversify local tuber derivative products have not developed optimally.

8. Conclusions

The border area is not only understood as a geographical concept of the region that is directly adjacent to other countries but also a strategic area that nationally concerns the lives of many people, whether or not it is reviewed for political, economic, social, cultural, and environmental and security defense interests. Local tubers in the border area of the Sangihe Islands Regency have the potential as base commodity plants and support technological innovations available to be developed both in terms of cultivation and industrial products with high economic value.

Some problems faced in the development of local tuber crops in the border area are, the potential for untapped land, climate and weather conditions in the border region that are erratic and often capricious, less motivation of farmers in improving the household economy through the business of cultivating crops and ownership of assets of farmers which is relatively small; then individual actions in business development will be very difficult in reaching optimal added value. Strategies that can be done in the development of local tubers to increase production and productivity in the border area of Sangihe Regency, among others, are regulations/policies repairing that support the business climate and infrastructure, institutional organization, development patterns of cooperation and partnership between government-private and community and research, development and innovation on cultivation technology and development of processed products with economic value.

9. Development policy implication

The government’s development efforts and strategies include accelerating the economic growth of border areas through people’s economic base with the availability of adequate infrastructure, conducive and constructive political stability to support economic growth in the region. This condition can be achieved through community empowerment by increasing the role and participation of communities in border areas and improving development management performance through improvement of the quality of government officials so that they can become facilitators of border area development.

For this reason, it is recommended that government officials as development policymakers should be able to encourage the management of natural resources in border areas based on superior commodities in increasing production and value chains. The development of local root crops is the main recommendation to improve food security which is still low in addition to improving the welfare of people with low purchasing power. To increase the productivity of local tuber farming, it is necessary to introduce superior seeds on time, including the provision of agricultural production facilities supported by the application of cultivation and post-harvest technology. Meanwhile, to improve the value chain, namely to strengthen the existence of farmer groups so that it not only increases bargaining power but also reduces transaction costs in marketing. Meanwhile, improving vertical coordination is carried out by establishing a network of partnerships with market players and fulfilling contractual agreements in profitable markets.