A Review of borneo buah engkabang ( Shorea macrophylla ) as potential omega-6 lipid source for fish feed

. Lipid is an essential source in fish feed production. Vegetable or fruit oil is becoming preferred by many fish feed manufacturers to replace fish oil, which is expensive and scarce. Buah Engkabang (Shorea macrophylla) is well known as the largest genera of the Dipterocarpaceae family and is a popular local fruit collected in tropical forests or nearby rivers in West Kalimantan (Indonesia) and Sarawak (Malaysia). Buah engkabang is seasonal fruit during the dry season, known among the Sarawak locals as a climatic species that ripens between January and March in a favorable environment. This review emphasizes morphology characteristics and phytochemical properties, including fatty acid components. In addition, this review also reviewed the application of engkabang oil in feed production, cooking oil, and other edible products. The high content of saturated fatty acids like palmitic acid, stearic acid, and oleic acids in engkabang product could be essential as the potential omega-six lipid source suitable for freshwater fish like empurau, kelah, and other local fish species found in riverine of Borneo. This eview will provide information on the potential use of buah engkabang as a future lipid source in fish feed production.


Distribution of buah engkabang
Shorea macrophylla, often referred to as the Engkabang by the local community of Sarawak, is predominantly found in the tropical rainforest of Southeast Asia, and it flourishes in alluvial deposits of soil that are frequently flooded along a riverside without human cultivation or interventions [1].These trees that grow widely and extensively along riverbanks in Borneo, especially in Sarawak and Kalimantan, are sourced from Engkabang seeds dispersed from the parent tree, which carries them alongside streams or rivers to other places [2].The native Engkabang is the largest genera under the Dipterocarpaceae family [3].
Local communities like the Iban who reside along riverbanks in Sarawak Malaysia are genuinely familiar with Shorea macrophylla fruit and utilize it for a great purpose, which comprises twenty species of the subfamily Shorea in the Dipterocarpaceae family [4].In the heart of Sarawak, the Kemena and Tatau River watersheds provide a supplier for wood and non-timber commodities such as Engkabang nuts [5].Kalimantan, which makes up 75 percent of the island (part of Indonesia,) is native to the diverse forests part of Borneo and is considered to be the native home to some 58 percent of dipterocarp species under the Dipterocarpaceae family according to [6] and [7].According to [6], Indonesia has the largest population species of Shorea that grow below 1300 m altitude.Out of the 196 identified species of Shorea in Indonesia, only 138 have been officially recorded.Over 100 Shorea species are classified as critically endangered [8] under the International Union for Conservation of Nature (IUCN) Red List.According to locals, Shorea macrophylla blooms during drought weather seasons from August to October, while they can be harvested fresh from January to March as they bloom with flowers and fruits.

Morphology of buah engkabang
Several overlapping and continuous traits in Shorea make it challenging to distinguish the species explicitly, complicating morphological character diversity [9].Engkabang is a fastgrowing wild tree with a distinguished rapid growth rate within 20 to 30 years [10].Its strong root can thrive or develop under primitive soil conditions like extremely wet and poor oxygen supply [11].This explains the wide distribution of this species along the riverines in Borneo.Studies on the Shorea macrophylla have been attentive and focused since the beginning.An earlier study by [12] states that all species of Shorea possess the persistent five calyces, including a surrounded thin woody shell encasing the four segments of the kernel.The fruit can be formed in various sizes within individual species and interspecifically.The largest specimen measured during the study was the fruit Shorea macrophylla, with a physical measurement of 7 cm long on the major axis and 5 cm on the minor axis.[13] stated that the engkabang tree has a sole leaf type with an oblong form and has 13 secondary leaf veins and tertiary leaf veins, which are highly evident, a petiole of 3 cm holding leaves that are 4.2 cm long and blunt-end bearing leaves.The Engkabang fruit grows massively in tropical regions, especially in countries such as Malaysia and Indonesia.Malaysia and Indonesia have significant differences in the morphology characteristics of Engkabang.According to [1] and [14], Shorea macrophylla can be found in an elliptical or spear-like form shaped in Malaysia.Engkabang trees can grow up to 15 to 20 m in length.It was also found that the months-old shorea plant has a potential height range of 67.19 to 88.79 cm with a pinpoint diameter of about 9.65 to 10.33 mm.In West Kalimantan, Shorea macrophylla is known to be a big tree with flat curving stipules and a bare exterior; the leaf grows from 20 to 30 cm long and has three calyx lobes that are roughly twice as long as the nut's actual size [15,16].

Physicochemicals of buah engkabang
Engkabang butter oil production is seasonal, and the butter oil can usually be found in local markets at Sibu, Miri, and also in Kapit.One hundred grams of engkabang butter oil obtained from an Iban's community at Kanowit, Sarawak, was analyzed for its fatty acid profile according to AOAC 20th Edition, 996.06 / GC-FID (Table 1).Results show that palmitic acid (16.80%), stearic acid (45.87%), and oleic acid (33.59%) as the main fatty acid components that make up more than 96% of fatty acid content in engkabang butter oil.A small quantity was determined in Shorea macrophylla for Arachidic acid (1.8836%) and Linoleic acid (0.7297%).These analysis results are similar to previous research by [17].

Table 1. Fatty acid Profile Shorea macrophylla
According to [18], palmitic acid is an anabolic precursor to the biosynthesis of longer fatty acids like stearic acid C18:0.Stearic acid is produced from the elongation of palmitate levels.To date, there are minimal studies on the effects of saturated fatty acids on growth performance in fish.A study by [19] described the potential antiviral mechanism of palmitic acid or (PA) treatment that reduces the mortality caused by spring viremia of carp virus (SVCV) infection both in vivo and in vitro in carps.This is due to the inhibition of the autophagic flux that is believed to be involved in the protection provided by PA.However, it was not advisable to administer PA at high dosages due to its toxic effects.This could indicate that PA may be capable of administrating antiviral effects in fish.Oleic acid is the most abundant monounsaturated fatty acid, and it was found in higher levels in freshwater fish in some places in Brazil [20] and even in marine species like Epinephelus fuscoguttatus × Epinephelus lanceolatus [21].The study found that fish supplemented with dietary oleic acid significantly (p < 0.05) enhanced immune responses to lysozyme, respiratory burst, and phagocytic activities during pre and postbacterial challenges.This further indicates that oleic acid in engkabang oil could provide promising results in elevating immune responses in fish.[22] stated that the diet of Malaysian mahseer might successfully incorporate illipe crude oil without hurting growth indications.Nevertheless, the application of all these saturated fatty acids in engkabang oil in the fish feed may be influenced by the interaction of diets and temperature, which was suggested by [23] and requires further research in the future.The total unsaturation of the amount of fatty acids that comprise the various vegetable oils is an important measurement to consider.The iodine value helps estimate the quality of fats and oils because the melting point and oxidative stability are determined by the degree of unsaturation [24,25].The Iodine Value (IV) of fat and oils can be calculated in various methods (Table 2).Wijs and Hanus procedure is a method that is often used to measure iodine value when compared to Hofman and Rosenmun.Only today, no recorded data or research shows that Hofman and Rosenmund's methods are used to measure iodine value (Tabel 3).-Engkabang fat's heating is higher than cocoa butter fat with one exothermic thermal transition at 21.1 ° C, and even the end set temperature was 24.95° C [17].It was discovered that the heating profile of Engkabang fat had a major transition at a temperature of 26.60 °C, a minor transition at a temperature of 33.65 °C, and an end set temperature of 35.25 °C (Figure 2).Variances in TAG distribution mostly caused the variances in their heating profiles.

Process of making buah engkabang oil
There are two ways to collect engkabang fruit: by picking it in the forest or river.Picking engkabang fruit under the tree in the forest is done during the dry season or on a day without rain.Engkabang oil is commonly used by locals in Sarawak today.[26] have illustrated the process of making Engkabang oil.The study shows that Illipe oil was extracted from Illipe fruits, according to Bligh and Dyer (1959).The fruits were dried in sunlight for a week to avoid molding before peeling.The process began with grinding 100 grams of dried, peeled fruits through a 600 μm mesh screen.Subsequently, the ground material was moistened using a vertical mixer to add distilled water until the moisture content reached roughly 80%.Following this, 100 mL of chloroform and 200 mL of methanol from Merk KGaA, Darmstadt, Germany, was added to the 100 grams of fruit powder.The resulting mixture was homogenized for 2 minutes using an IKA-Ultra-Turrax T5 FU homogenizer.100 mL of chloroform was added, and the mixture was homogenized for 30 seconds.After adding 100 mL of distilled water, the homogenization process was repeated for 30 seconds.After filtering, the resultant homogenate was allowed to stand for around 12 hours.The bottom layer was then meticulously gathered into a flask with a circular bottom.The chloroform was subsequently allowed to evaporate at a temperature of 70°C thanks to the flask's connection to a rotating evaporator (Heidolph GmbH).

Market status of buah engkabang
The only variety of fruit that is constantly sold simply for money is the "engkabang" fruit, and this is because it is usually dried.Its oil is extracted for industrial uses rather than sold as a food product for human consumption and fish feed formulation [5,27].The products from the Engkabang tree and fruit have the potential to develop a high market trend.[28] stated that commercial hardwood timber no longer satisfies the demand in the current market.To replace such timber, this engkabang tree presents itself as a promising indigenous wood species suitable for various structural purposes that can be effectively employed in tasks such as interior plywood and door production, which is affordable for the local community.
Among the famous debates about Shorea macrophylla is the market competition of cocoa butter product industries.Regarding this statement, [29] has specified that illipe nut exports have long been directly related to the production of chocolate.This is very beneficial for making artificial chocolate eggs.Because of the composition of fat, which has an excellent melting point temperature, it is being used to manufacture alternative chocolates sold highly in tropical countries.The cost of cocoa butter is 65 percent higher than that of illipe butter, which tells how affordable illipe butter is.West Kalimantan exported more than 3519.2tonnes of illipe nuts in the early nineties for a total of USD 7,70780 [30,27].Harvesting and selling illipe nuts has long been a source of additional income for West Kalimantan residents.Up to 800 kilograms of nuts can be harvested from one illipe tree each harvest season, as they can survive for more than a century [31].According to [32], Engkabang nut is presently becoming scarce in its native environment, and it is difficult to find or locate in the market sector as a result of its massive utilization in response and the market price for engkabang butter is accounted to be RM 350 per kilograms.

Flowering season for buah engkabang
According to [29], the Shorea species is known as a typical flower, and it flourishes during mast flowering periods, which take place at unpredictable intervals over several years.This study stated that numerous research were done on the seasonal conditions of Shorea macrophylla.However, the unpredictable season interval still needs clarification and is difficult to anticipate.Another study by [1] stated that Engkabang fruit ripens between the early months of the year till March in a suitable environment, and the blooming eventually starts after 15 or 16 years.However, it might be a while before the next blossoming happens.Eventually, in a large region of Sarawak, the dry season begins around the middle of the year in certain areas in the east, and there is a propensity for two dry seasons before the equinoxes [33].[12] has thoroughly described that flowering and fruit growth usually takes place in the weeks just before the rainy season begins as mature fruits fall from the trees between February and May of the year.The flowering period occasionally happens after the humid, wet season, and a small amount of fruit typically falls towards the end of the same year.The records from this study show that limited "autumn" ones frequently follow successful "spring" crops, and the growth of Engkabang flowering is highly dependent on the periodicity of climate seasonal change [34].Shorea macrophylla is considered a climax species as they gradually grow under limited resources.[35] stated that their life techniques vary from normal pioneer tree species, and their flowering and fruiting are exceptional with the generation of large seeds without dormancy, shade tolerance, and towering stature.According to [6], some species of Shorea have been widely planted across regions, but most of the seeds are being collected from the forest as they typically cannot be kept for an extended period.The seed will be hard to germinate if not harvested during the fruit season.Some wild animals, such as wild boars, prefer the seeds since they are not only refractory but also like consuming vegetable fat.Thus, very few Shorea fruits eventually germinate due to scavenging by wild forest creatures.[36] has justified that Shorea macrophylla takes five months from flowering to fruiting, which blooms in late September or early October.But in addition to erratic yearly flowering, both seasons may vary within a single year in distinct local locations

Iban community and buah engkabang
The consanguinity of the buah engkabang and Iban community is stereotyped.Among the links that can be discussed are tattoos, which are social signs and contain a community belief in the meaning of the tattoo.According to [37], the engkabang tree is naturally essential as its fruit is believed to be useful as a cosmetic ingredient and also a raw material for oil fryers for the Iban community in ancient times.This makes the plant have a unique value among the Iban people both in West Kalimantan and also the Iban people in Sarawak.Therefore, the engkabang fruit or tengkawang is a model for Iban traditional tattoo motifs carved on the stomach, middle back, and back above as symbols of the source of life for the Iban community.There are several common designs of buah engkabang tattoos (Figure 3).Tattoo engkabang is generally carved on the back thigh or calf of a man's leg, which gives meaning to wandering, and fruits engkabang as food continues to live outside the community area [38].In addition, another tattoo is placed on the back of the body.Another particular morphology of buah engkabang is that it drops or flies like a helicopter from a tree by spiral moving through the air with the help of its "wings."Hence, Ibans relate the special morphology to the parang (machete) swing during Figurine and the performance of the ajat dance [39].Fig. 4. The motive of these tattoo fruit is to serve as a source of food to continue living when the tattoo owner walks far to a place, especially during their wanderings.Engkabang tattoo is a symbol that indicates a person's life journey is long, and the fruit is a source of food or strength to live life.

Buah engkabang as potential fish feed 2.1 Feed for fish
Particularly in the jungles of Sarawak and Kalimantan, illipe, or Shorea macrophylla, also known as bright red meranti or engkabang, is widely distributed; these species of fruit have a high lipid content that is primarily composed of consistent beneficial triglycerides with the main fatty acids [26,41].Wild animals, woodpeckers, wolves, rats, freshwater fish, squirrels, and native reindeer consume the illipe nuts.These nuts have a high oil content with the most advantageous unsaturated triglycerides [1].According to [26], Tambroides, commonly known as Empurau, imperatively consume various zooplankton, including algae, aquatic species, and small fishes.In terms of behavior, in the morning, the fish swim back to the deep waters after scavenging in the shallower sections as they gather near specific tree species along riverbanks to eat the fruits that have fallen from the trees.The author has researched the performances of crude illipe oil (Shorea macrophylla) as the dietary lipid source for riverine cyprinid Tor tambroides, and he stated Mansheer and other species such as Tor khudree, Tor putitora, Tor laterivittatus, and Tor sinensis widely eat the Shorea fruits.Engkabang fruit is frequently used as cocoa butter substitute fat, encompassing fat levels from 52 percent to 53.9 percent; thus, it is a highly suitable replacement for cocoa butter [41].[26] findings state that when feeding T. tambroides, the Engkabang retains internal dietary lipid, energy, and polyunsaturated fatty acids somewhat less effectively than crude palm oil.Wild fishes consume engkabang, which is rich in lipids and provides a delicious flavor to the meat as they are significantly more costly than their farmed equivalents.Still, until today, no proven data show the efficacy of Shorea macrophylla on meat quality for Malayan mashers [42,43].Most empurau fish research studies have predominantly centered on growth performance by replacing protein or lipid with new trending feed ingredients, including crab shell waste, Black soldier fly, or canarium fruits [22,44,45,46].Very little research has been conducted on Engkabang with fish feed replacement, which requires intensive focus in the coming future.

Conclusion
In conclusion, this review has provided insight into some of the latest information on Shorea macrophylla.This fruit and flower of Shorea have become popular in recent years due to massive exploitations in many regions.The Engkabang is impacting Engkabang oil production in countries as an effective resource.This review enables us to understand the vitality of Buah Engkabang towards the Iban community as a source of energy and spirit to continue their daily life routines.The leading information through this review delivers the potential properties of Engkabang, which can be utilized as fish feed.The Malaysian mahseer and other riverine cyprinids habitually eat illipe fruit.Using Engkabang Oil as a fish feed supplement may impact the fish's sensory qualities, shelf life, and quality.There are very few studies regarding Buah Engkabang, which suggests that in the future, extensive research studies will be conducted on it to create a better understanding and comprehensive beneficial productions from Shorea macrophylla.This review will essentially benefit in terms of the conception of Engkabang origin and infuse more on the significance of it to the environment and economy as a potential lipid source for fish feed.

Table 2 .
Iodine Value, Yield, and Slip Melting Point of Engkabang Fat

Table 3 .
Methods to measure Iodine Value