Gelatin; Switch back to Halal: A Mini-Review

Author's: Rahat Sharif*
Authors' Affiliations
College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi Province 712100, China.*Corresponding Author: Rahat Sharif;
Article Type: Mini-Review     Published: Apr. 09, 2019 Pages: 63-73
DOI:        Views 2077       Downloads 0


Gelatin is a traditional functional protein with water-soluble properties and has the potential of forming transparent gels under certain conditions. The main source of gelatin is pigskin and is widely used in processed food and medicinal products. Though the use of food products adulterated with porcine-derived gelatin create concerns in the mind of Muslims community, as in Islam, it is not acceptable or literally, we call it Haram. However, in recent times initiatives have been taken in producing gelatin from Halal sources, such as fish, chicken and bovine slaughtered according to Islamic teachings. Therefore, we highlighted different porcine alternative derived gelatin sources and also methods to detect edible product adulterated with pork or other haram stuff. This review could be useful in providing information to a large number of audience and food processing companies to minimize or if possible eradicate the use of porcine-derived gelatin in commercial food and medicinal products.


Gelatin, Muslims, Halal, fish, chicken.


Sharif, R., 2019. Gelatin; Switch back to Halal: A Mini-Review. PSM Biol. Res., 4(2): 63-73.


Gelatin is a fibrous protein with high molecular weight, derived from collagen which comprises about 25 to 35% of total body protein, through thermal hydrolysis (Tabarestani et al., 2010; Vijayaraghavan et al., 2009). It is the main protein connective tissue and widely found in mammals, birds, and fishes (Eysturskarð et al., 2009; Rawdkuen et al., 2013). In general, gelatin plays a role in food processing and formulation (i.e. gelling process and some respond to the surface behavior of gelatin) (Karim and Bhat, 2008). The other functional properties of gelatin are of foaming, emulsifying, setting index and water holding capacity (Rawdkuen et al., 2013). Gelatin is commercially used in food, pharmaceutics, cosmetics, and photographic application (Figueroa-Lopez et al., 2018; Nur Hanani et al., 2013; Rose et al., 2014; Salamon et al., 2014; Schrieber and Gareis, 2007).

   The Muslim population share 23.4% of the total world population (1.6 billion), which has been reported by Jamaluddin et al (Jamaludin et al., 2011). The ever-growing Muslim population and demands for halal food are on the rise (Easterbrook and Maddern, 2008). Regarding the increase in demand of halal food, an issue is raised by many scholar and scientist that, gelatin which is mainly derived from the pig skin (Boran and Regenstein, 2010) is used in almost every processed food products. However, Muslim do not approve gelatin derived from prohibited sources like porcine gelatin except the extreme situation where there is no other alternative (Eriksson et al., 2013). In contrast to that, pork derived gelatin can be replaced by using gelatin derived from halal sources. Such as fish (Mahmoodani et al., 2014), cow (Andiç et al., 2013), chicken and turkey(Du et al., 2013) derived gelatin.             In the recent past, a handsome amount of review article has been published (Babel, 1996; Djagny et al., 2001; Karim and Bhat, 2008; Mariod and Fadul, 2013). However, based on our exploration capability, no comprehensive study is available to clearly distinguish between porcine and it’s alternative (Halal) derived gelatin. The need of this study is to shed light over the issue of Halal and Haramgelatin-based products consumptions. Further, showcased its importance in improving antioxidant activities and also outline some methodology to detect porcine adulteration and market data of major Islamic countries. This review might be helpful in the future regarding knowledge and significance about porcine and its Halal alternative derived gelatin.

Sources of Gelatin

The primary source of gelatin is pigskin, but some other sources are also contributing in fulfilling the requirement of gelatin production (Boran and Regenstein, 2010; Sai-Ut et al., 2012). As it contributes 46% to the total production of gelatin along with bovine hide (29.4) and pork and cattle bones (23.1%) (Gómez-Guillén et al., 2011). However, a considerable amount of attention has been given to the alternatives of porcine gelatin (Morrison et al., 1999). Further talking about porcine-derived gelatin alternatives, the fish gelatin market share is still very small comparing to bovine and porcine gelatin (Choi and Regenstein, 2000). But there are a sizeable amount of available scientific studies reported that aquatic source derived gelatin exhibit better film-forming properties than that of mammalians (Avena‐Bustillos et al., 2011). In addition to that, fish gelatin with a lower melting point was reported for having good release properties of food sensory attributes (Aewsiri et al., 2009). Therefore, it became an important issue to provide gelatin derived from Halal Sources. In contrast to which, gelatin derived from poultry, animals (considered as Halal and slaughter according to according Islamic rules)  and especially marine sources (Bhat and Karim, 2009) can be accepted as Halal and might be a potential alternative for porcine gelatin (Table 1).

sources of gelatin

Commercial uses of Gelatin

The unique gelling, stabilizing, healing, ointment, capsule and coating properties of gelatin made it as the most widely used biodegradable compound in commercial food produces, pharmaceutical and photographic industries (Djagny et al., 2001; Howe, 2000; Ulubayram et al., 2001; van Eerd et al., 2006; Wang et al., 2012). The clear and transparent structure of gelatin accounts for its significance, especially in food and pharmaceutical industries (Djagny et al., 2001). Further, it has been reported that, annually, tons of gelatin has been used in candies, desert, meat, ice cream and bakery products (Djagny et al., 2001; Johnston-Banks, 1990). Moreover, the gelatin also inhibits the recrystallization of lactose sugar during cold storage (Jamilah and Harvinder, 2002). While in pharmaceutical industries, the making of hard and soft capsule shell, tablets, granulation and syrups, all required gelatin. Because the gelatin serves as a natural coating material and also highly digestible. According to a report, approximately 6% of the total gelatin production is used in pharmaceutical industries (Hidaka and Liu, 2003). For sports industry, gelation does play its role in energy drinks production for athlete also utilize gelatin as a necessary component of energy drink (Phillips and Williams, 2011). In photography, it was first used in 1871 after coating the sensitizing agent on a glass plate in gelatin. Furthermore, the use of gelatin in cosmetic industries is of high importance, as it is commonly used in shampoo, lipstick, conditioner, cream and fingernail formulas (link available for reference # 54 in the reference section) ( Furthermore, gelatin derived from aquatic sources may be more applicable in the halal/kosher market than that of mammalian and porcine gelatin.

Antioxidant properties of gelatin derived from Halal and porcine sources

The increase in the production of biodegradable polymer like gelatin getting worldwide attention, one of the reasons why producer finds it as an attractive option is due to its antioxidant properties (Arvanitoyannis, 2002; Kavoosi et al., 2013). There are many sources of gelatin, however, there is a notable growing interest in producing gelatin from fish waste because of the outbreak of mad cow disease and the unacceptability of bovine and porcine-derived gelatin by Muslims, Jews and Hindus community (Haug et al., 2004). Adding to this, fish gelatin possess biologically active peptide and such peptides have the potential to act as an antioxidant against the like of linoleic acid (Kim et al., 2001b; Mendis et al., 2005). Further, the fish gelatin hydrolyzes with papain to produce antioxidant peptides, which exhibit high radical scavenging properties (You et al., 2010). In contrast to that, hydrolysate derived from fish gelatin can be used as a functional food material that induces immunity against ultraviolet A in the skin and also protects food and others biological system from oxidation (Kato et al., 2011; Sai-Ut et al., 2012). Moreover, the gelatin derived from the Pacific cod skin was hydrolyzed with pepsin and produced two bioactive peptides namely GASSGMPG (662 Da) and LAYA (436 Da) (Ngo et al., 2016). This showed the strong inhibitory effect of Angiotensin- I- converting enzyme (ACE), an important enzyme in the control of hypertension and type-2 diabetes (Ngo et al., 2016). Further, they suggested using it in functional food preparation to lower the blood pressure and cardiovascular diseases (CVD) (Ngo et al., 2016). In another study, gelatin from cuttlefish was reported for stopping the β-carotene bleaching by donating an atom to peroxyl radicals of linoleic acid. Which further demonstrated its importance in protecting food from drying and exposure to light (Jridi et al., 2013). Meanwhile, gelatin derived from the poultry waste also exhibit metal chelating and radical scavenging properties and can be considered as a Halal alternative of porcine gelatin (Omar and Sarbon, 2016). Some other valuable peptides were also reported for its beneficial activity by many researchers confirmed the broad and wide range of available and functional peptides from porcine alternative sources (Kim et al., 2001a; Kim et al., 2001b; Mendis et al., 2005; Nakade et al., 2008; Saiga et al., 2008). Thereby, according to Jridi et al (Jridi et al., 2013), all gelatins in all probability contained peptides which are electron or hydrogen donors that converts the free radical to the more stable product by reacting with them and dismiss the radical chain reaction (Jridi et al., 2013). However, we will suggest after studying the recent research that fish gelatin (advantage of having odorless properties) has an edge over poultry gelatin due to the complication in managing poultry wastes (Jayathilakan et al., 2012). Therefore fish gelatin can be utilized as a substitute antioxidant driver for porcine and bovine-derived gelatin.

Techniques regarding detection of porcine adulteration

In the recent times, about 50,000 tons of beef meat has been found adulterated with horse meat in Europe (Ahmad, 2009). This cannot be an accident but a fraudulent act to mix the meat of different species such as horse or pork and blend it into the cattle beef, which creates concerns in the mind of ethnical groups (Muslims and Jews) (von Bargen et al., 2013). As the 1.5 billion Muslims shares around 20% of the world population and for them, the use of porcine-derived food products is strictly prohibited according to the teaching of Islam (Shabani et al., 2015; von Bargen et al., 2013).  Such is the case with the production of gelatin as well. According to a report, about 80% of gelatin produced from the pigskin in Europe (Boran and Regenstein, 2010). In addition to that, most of the food manufacturers use porcine-derived gelatin rather than its diverse alternatives (Batu et al., 2015; Shabani et al., 2015). Due to the vast use of porcine gelatin, it is must for the Muslims to test the processed food for the detection of porcine-derived gelatin adulteration (Riaz and Chaudry, 2003). Because for the Muslim, the tolerance level becomes 0% when it comes to porcine and porcine-derived gelatin contamination in processed foods (von Bargen et al., 2013). Therefore we tabulated some of the advanced techniques regarding the detection of porcine gelatin in food products, from the previously published research articles (Table 2).

techniques for screening

Opportunity for industrial and market boost

The contribution from the waste of livestock, fisheries and poultry industry is important for a country GDP growth (Jayathilakan et al., 2012). The main reason is that animal byproducts have the capability of decreasing the level of protein malnutrition and food insecurity (Alao et al., 2017). According to the available online data, Muslim countries produce heaves of animal waste and do have the potential of producing a large amount of Halalgelatin (Table 3). However, the exported values (table 3) showing a huge gap between the production of gelatin and the other variables (Meat and fisheries). This clearly showcasing the poor management of animal byproducts in all the major Islamic countries. The reason might be lack of production facility and less knowledge about managing animal waste products. Therefore more attention is needed particularly in the area of managing waste from farm animals, aquatic sources and poultry industry. As it is important to boost the local market economy, decrease concerns regarding the use of Halal and Haramgelatin and also increase the country economy by reducing the percentage of imported gelatin.

mear, fish and gelatin


The need for this review is to highlight the issue regarding Halal and Haram gelatin. As the major gelatin source in the international market is pigskin but it is always controversial for ethnical groups, such as Muslims and Jews. Therefore we summarized different porcine alternative gelatin sources, which provide better gelling, antioxidant and functional properties than that of porcine-derived gelatin. In addition to that, we tabulated some market data of major Islamic countries, which clearly suggests that all those stated countries have the ability to produce handsome amount of Halal gelatin and can make themselves gelatin sufficient. However, apart from Turkey, all other countries are producing gelatin less than their average requirement. The reasons must be varied such as lack of waste management practices and industrial technology. Therefore, more work is required in the sector of waste management and adopting state of the art industrial technology to produce Halal gelatin inside the country.


The author declares that no conflict of interest exists.


Abdullah, M.S.P., Noordin, M.I., Ismail, S.I.M., Nyamathulla, S., Jasamai, M., WAI, L., Mustapha, N.M., 2016. Physicochemical evaluation and spectroscopic characterisation of gelatine from shank and toes of Gallus gallus domesticus. Sains Malaysiana, 45(3): 435-449.

Abedinia, A., Ariffin, F., Huda, N., Nafchi, A.M., 2017. Extraction and characterization of gelatin from the feet of Pekin duck (Anas platyrhynchos domestica) as affected by acid, alkaline, and enzyme pretreatment. Int. J Biol. Macromol., 98: 586-594.

Aewsiri, T., Benjakul, S., Visessanguan, W., Eun, J.-B., Wierenga, P.A., Gruppen, H., 2009. Antioxidative activity and emulsifying properties of cuttlefish skin gelatin modified by oxidised phenolic compounds. Food Chem., 117(1): 160-168.

Ahmad, M., Qureshi, R., Arshad, M., Khan, M. A., Zafar, M.,, 2009. Ethnomedicinal survey of plants from salt range (Kallar Kahar) of Pakistan. Pak. J. Bot., 40(3): 1005-1011.

Alao, B.O., Falowo, A.B., Chulayo, A., Muchenje, V., 2017. The Potential of Animal By-Products in Food Systems: Production, Prospects and Challenges. Sustainability, 9(7): 1089.

Almeida, P.F., Lannes, S.C.d.S., 2013. Extraction and Physicochemical Characterization of Gelatin from Chicken By‐Product. J. Food Process Engin., 36(6): 824-833.

Andiç, S., Boran, G., Tunçtürk, Y., 2013. Effects of Carboxyl Methyl Cellulose and Edible Cow Gelatin on Physico-chemical, Textural and Sensory Properties of Yoghurt. Int. J. Agric. Biol., 15(2): 245-251.

Arvanitoyannis, I.S., 2002. Formation and properties of collagen and gelatin films and coatings. Protein-based films and coatings, 467: 484.

Avena‐Bustillos, R., Chiou, B.-s., Olsen, C., Bechtel, P., Olson, D., McHugh, T., 2011. Gelation, oxygen permeability, and mechanical properties of mammalian and fish gelatin films. J. Food Sci., 76(7): E519-24.

Babel, W., 1996. Gelatine–ein vielseitiges Biopolymer. Chemie in unserer Zeit, 30(2): 86-95.

Batu, A., Regenstein, J.M., Dogan, I.S., 2015. Gelatin issues in halal food processing for muslim societies. Int. Periodical for the Languages, Literature and History of Turkish or Turkic., 10(14): 37-52.

Bhat, R., Karim, A., 2009. Ultraviolet irradiation improves gel strength of fish gelatin. Food Chem., 113(4): 1160-1164.

Boran, G., Regenstein, J.M., 2010. Fish gelatin. Adv. Food Nutr.Res., 60: 119-143.

Chandra, M., Shamasundar, B., 2015. Rheological properties of gelatin prepared from the swim bladders of freshwater fish Catla catla. Food Hydrocolloid., 48: 47-54.

Choi, S.S., Regenstein, J., 2000. Physicochemical and sensory characteristics of fish gelatin. J. Food Sci., 65(2): 194-199.

Demirhan, Y., Ulca, P., Senyuva, H.Z., 2012. Detection of porcine DNA in gelatine and gelatine-containing processed food products—Halal/Kosher authentication. Meat Sci., 90(3): 686-689.

Djagny, K.B., Wang, Z., Xu, S., 2001. Gelatin: a valuable protein for food and pharmaceutical industries. Crit. Rev. Food Sci. Nutr., 41(6): 481-492.

Du, L., Khiari, Z., Pietrasik, Z., Betti, M., 2013. Physicochemical and functional properties of gelatins extracted from turkey and chicken heads. Poult. Sci., 92(9): 2463-2474.

Easterbrook, C., Maddern, G., 2008. Porcine and bovine surgical products: Jewish, Muslim, and Hindu perspectives. Arch. Surg., 143(4): 366-370.

Eriksson, A., Burcharth, J., Rosenberg, J., 2013. Animal derived products may conflict with religious patients’ beliefs. BMC Med.l Ethic., 14(1): 48.

Eysturskarð, J., Haug, I.J., Elharfaoui, N., Djabourov, M., Draget, K.I., 2009. Structural and mechanical properties of fish gelatin as a function of extraction conditions. Food Hydrocolloid., 23(7): 1702-1711.

Figueroa-Lopez, K.J., Andrade-Mahecha, M.M., Torres-Vargas, O.L., 2018. Development of Antimicrobial Biocomposite Films to Preserve the Quality of Bread. Molec., 23(1): 212.

Gómez-Guillén, M., Giménez, B., López-Caballero, M.a., Montero, M., 2011. Functional and bioactive properties of collagen and gelatin from alternative sources: A review. Food Hydrocolloid., 25(8): 1813-1827.

Gómez-Guillén, M., Turnay, J., Fernández-Dıaz, M., Ulmo, N., Lizarbe, M., Montero, P., 2002. Structural and physical properties of gelatin extracted from different marine species: a comparative study. Food Hydrocolloid., 16(1): 25-34.

Hafidz, R., Yaakob, C., Amin, I., Noorfaizan, A., 2011. Chemical and functional properties of bovine and porcine skin gelatin. Int. Food Res. J., 18(2011): 813-817.

Haug, I.J., Draget, K.I., Smidsrød, O., 2004. Physical behaviour of fish gelatin-κ-carrageenan mixtures. Carbohydr. Polym., 56(1): 11-19.

Hidaka, S., Liu, S., 2003. Effects of gelatins on calcium phosphate precipitation: a possible application for distinguishing bovine bone gelatin from porcine skin gelatin. J. Food Compos. Anal., 16(4): 477-483.

Howe, A.M., 2000. Some aspects of colloids in photography. Curr. Opin. Colloid Interface Sci., 5(5-6): 288-300.

Jamaludin, M.A., Zaki, N.N.M., Ramli, M.A., Hashim, D., Rahman, S., 2011. Istihalah: analysis on the utilization of Gelatin in food products, 2nd Int. Conf. on Humanities, Historical and Social Sci., IPEDR.

Jamilah, B., Harvinder, K., 2002. Properties of gelatins from skins of fish—black tilapia (Oreochromis mossambicus) and red tilapia (Oreochromis nilotica). Food Chem., 77(1): 81-84.

Jayathilakan, K., Sultana, K., Radhakrishna, K., Bawa, A., 2012. Utilization of byproducts and waste materials from meat, poultry and fish processing industries: a review. J. Food Sci. Technol., 49(3): 278-293.

Johnston-Banks, F., 1990. Gelatine, Food gels. Springer, pp. 233-289.

Jongjareonrak, A., Rawdkuen, S., Chaijan, M., Benjakul, S., Osako, K., Tanaka, M., 2010. Chemical compositions and characterisation of skin gelatin from farmed giant catfish (Pangasianodon gigas). LWT-Food Sci. Technol., 43(1): 161-165.

Jridi, M., Souissi, N., Mbarek, A., Chadeyron, G., Kammoun, M., Nasri, M., 2013. Comparative study of physico-mechanical and antioxidant properties of edible gelatin films from the skin of cuttlefish. Int. J. Biol. Macromol., 61: 17-25.

Karim, A., Bhat, R., 2008. Gelatin alternatives for the food industry: recent developments, challenges and prospects. Trends Food Sci. Technol., 19(12): 644-656.

Kato, S., Matsui, H., Saitoh, Y., Miwa, N., 2011. Fish collagen-containing drink is subcutaneously absorbed and attenuates the UVA-induced tissue-integrity destruction and DNA damages in 3D-human skin tissue model. J. Funct. Foods., 3(1): 50-55.

Kavoosi, G., Dadfar, S.M.M., Mohammadi Purfard, A., Mehrabi, R., 2013. Antioxidant and antibacterial properties of gelatin films incorporated with carvacrol. J. Food Saf., 33(4): 423-432.

Kim, S.K., Byun, H.G., Park, P.J., Shahidi, F., 2001a. Angiotensin I converting enzyme inhibitory peptides purified from bovine skin gelatin hydrolysate. J. Agric. Food Chem., 49(6): 2992-2997.

Kim, S.K., Kim, Y.T., Byun, H.G., Nam, K.S., Joo, D.S., Shahidi, F., 2001b. Isolation and characterization of antioxidative peptides from gelatin hydrolysate of Alaska pollack skin. J. Agric. Food Chem., 49(4): 1984-1989.

Koli, J.M., Basu, S., Nayak, B.B., Patange, S.B., Pagarkar, A.U., Gudipati, V., 2012. Functional characteristics of gelatin extracted from skin and bone of Tiger-toothed croaker (Otolithes ruber) and Pink perch (Nemipterus japonicus). Food Bioprod. Process., 90(3): 555-562.

Lee, J.H., Kim, M.R., Jo, C.H., Jung, Y.K., Kwon, K., Kang, T.S., 2016. Specific PCR assays to determine bovine, porcine, fish and plant origin of gelatin capsules of dietary supplements. Food Chem., 211: 253-259.

Mad‐Ali, S., Benjakul, S., Prodpran, T., Maqsood, S., 2016. Characteristics and gel properties of gelatin from goat skin as affected by pretreatments using sodium sulfate and hydrogen peroxide. J. Sci. Food Agric., 96(6): 2193-2203.

Madhamuthanalli, C.V., Bangalore, S.A., 2014. Rheological and physico‐chemical properties of gelatin extracted from the skin of a few species of freshwater carp. Int. J. Food Sci. Technol., 49(7): 1758-1764.

Mahmoodani, F., Ardekani, V.S., See, S., Yusop, S.M., Babji, A.S., 2014. Optimization and physical properties of gelatin extracted from pangasius catfish (Pangasius sutchi) bone. J. Food Sci. Technol., 51(11): 3104-3113.

Mariod, A.A., Fadul, H., 2013. gelatin, source, extraction and industrial applications. Acta Sci. Pol. Technol. Aliment., 12(2): 135-147.

Mendis, E., Rajapakse, N., Kim, S.-K., 2005. Antioxidant properties of a radical-scavenging peptide purified from enzymatically prepared fish skin gelatin hydrolysate. J. Agric. Food Chem., 53(3): 581-587.

Mokrejs, P., Langmaier, F., Mládek, M., Janacova, D., Kolomazník, K., Vasek, V., 2009. Extraction of collagen and gelatine from meat industry by-products for food and non food uses. Waste Manag. Res., 27(1): 31-37.

Morrison, N., Clark, R., Chen, Y., Talashek, T., Sworn, G., 1999. Gelatin alternatives for the food industry, Physical chemistry and industrial application of gellan gum. Springer, pp. 127-131.

Muyonga, J., Cole, C., Duodu, K., 2004. Extraction and physico-chemical characterisation of Nile perch (Lates niloticus) skin and bone gelatin. Food Hydrocolloid., 18(4): 581-592.

Nakade, K., Kamishima, R., Inoue, Y., Ahhmed, A., Kawahara, S., Nakayama, T., Maruyama, M., Numata, M., Ohta, K., Aoki, T., 2008. Identification of an antihypertensive peptide derived from chicken bone extract. Anim. Sci. J., 79(6): 710-715.

Ngo, D.-H., Vo, T.-S., Ryu, B., Kim, S.-K., 2016. Angiotensin-I-converting enzyme (ACE) inhibitory peptides from Pacific cod skin gelatin using ultrafiltration membranes. Process Biochem., 51(10): 1622-1628.

Nikzad, J., Shahhosseini, S., Tabarzad, M., Nafissi-Varcheh, N., Torshabi, M., 2017. Simultaneous detection of bovine and porcine DNA in pharmaceutical gelatin capsules by duplex PCR assay for Halal authentication. DARU J. Pharmac. Sci., 25(1): 3.

Nur Hanani, Z.A., Beatty, E., Roos, Y.H., Morris, M.A., Kerry, J.P., 2013. Development and characterization of biodegradable composite films based on gelatin derived from beef, pork and fish sources. Foods, 2(1): 1-17.

Omar, W.H.W., Sarbon, N., 2016. Effect of drying method on functional properties and antioxidant activities of chicken skin gelatin hydrolysate. J. Food Sci. Technol., 53(11): 3928-3938.

Phillips, G.O., Williams, P.A., 2011. Handbook of food proteins. Elsevier.

Ran, X.G., Wang, L.Y., 2014. Use of ultrasonic and pepsin treatment in tandem for collagen extraction from meat industry by‐products. J. Sci. Food Agric., 94(3): 585-590.

Rawdkuen, S., Thitipramote, N., Benjakul, S., 2013. Preparation and functional characterisation of fish skin gelatin and comparison with commercial gelatin. Int. J. Food Sci. Technol., 48(5): 1093-1102.

Riaz, M.N., Chaudry, M.M., 2003. Halal food production. CRC press.

Rose, J.B., Pacelli, S., Haj, A.J.E., Dua, H.S., Hopkinson, A., White, L.J., Rose, F.R., 2014. Gelatin-based materials in ocular tissue engineering. Mater., 7(4): 3106-3135.

Sai-Ut, S., Jongjareonrak, A., Rawdkuen, S., 2012. Re-extraction, recovery, and characteristics of skin gelatin from farmed giant catfish. Food and Bioprocess Technol., 5(4): 1197-1205.

Saiga, A., Iwai, K., Hayakawa, T., Takahata, Y., Kitamura, S., Nishimura, T., Morimatsu, F., 2008. Angiotensin I-converting enzyme-inhibitory peptides obtained from chicken collagen hydrolysate. J. Agric. Food Chem., 56(20): 9586-9591.

Salamon, A., Van Vlierberghe, S., Van Nieuwenhove, I., Baudisch, F., Graulus, G.-J., Benecke, V., Alberti, K., Neumann, H.-G., Rychly, J., Martins, J.C., 2014. Gelatin-based hydrogels promote chondrogenic differentiation of human adipose tissue-derived mesenchymal stem cells in vitro. Mater., 7(2): 1342-1359.

Samal, S.K., Goranov, V., Dash, M., Russo, A., Shelyakova, T., Graziosi, P., Lungaro, L., Riminucci, A., Uhlarz, M., Bañobre-López, M., 2015. Multilayered magnetic gelatin membrane scaffolds. ACS Appl. Mater. Interfaces., 7(41): 23098-23109.

Schrieber, R., Gareis, H., 2007. Gelatine handbook: theory and industrial practice. John Wiley & Sons.

Shabani, H., Mehdizadeh, M., Mousavi, S.M., Dezfouli, E.A., Solgi, T., Khodaverdi, M., Rabiei, M., Rastegar, H., Alebouyeh, M., 2015. Halal authenticity of gelatin using species-specific PCR. Food Chem., 184: 203-206.

Sinthusamran, S., Benjakul, S., Kishimura, H., 2015. Molecular characteristics and properties of gelatin from skin of seabass with different sizes. Int. J. Biol. Macromol., 73: 146-153.

Souissi, N., Abdelhedi, O., Mbarek, A., Kammoun, W., Kechaou, H., Nasri, M., 2017. Gelatin based bio-films prepared from grey triggerfish’skin influenced by enzymatic pretreatment. Int. J. Biol. Macromol., 105: 1384-1390.

Sudjadi, Wardani, H.S., Sepminarti, T., Rohman, A., 2016. Analysis of porcine Gelatin DNA in a commercial capsule shell using real-time polymerase chain reaction for halal authentication. Int. J. Food Prop., 19(9): 2127-2134.

Tabarestani, H.S., Maghsoudlou, Y., Motamedzadegan, A., Mahoonak, A.S., 2010. Optimization of physico-chemical properties of gelatin extracted from fish skin of rainbow trout (Onchorhynchusmykiss). Biores. Technol., 101(15): 6207-6214.

Tasara, T., Schumacher, S., Stephan, R., 2005. Conventional and real-time PCR–based approaches for molecular detection and quantitation of bovine species material in edible gelatin. J. Food Protec., 68(11): 2420-2426.

Ulubayram, K., Cakar, A.N., Korkusuz, P., Ertan, C., Hasirci, N., 2001. EGF containing gelatin-based wound dressings. Biomaterials, 22(11): 1345-1356.

van Eerd, J.E., Vegt, E., Wetzels, J.F., Russel, F.G., Masereeuw, R., Corstens, F.H., Oyen, W.J., Boerman, O.C., 2006. Gelatin-based plasma expander effectively reduces renal uptake of 111In-octreotide in mice and rats. J. Nucl. Med., 47(3): 528-533.

Vijayaraghavan, R., Thompson, B., MacFarlane, D., Kumar, R., Surianarayanan, M., Aishwarya, S., Sehgal, P., 2009. Biocompatibility of choline salts as crosslinking agents for collagen based biomaterials. Chem. Commun., 46(2): 294-296.

von Bargen, C., Dojahn, J.r., Waidelich, D., Humpf, H.-U., Brockmeyer, J., 2013. New sensitive high-performance liquid chromatography–tandem mass spectrometry method for the detection of horse and pork in halal beef. J. Agric. Food Chem., 61(49): 11986-11994.

Wang, T., Zhu, X.-K., Xue, X.-T., Wu, D.-Y., 2012. Hydrogel sheets of chitosan, honey and gelatin as burn wound dressings. Carbohydr. Poly., 88(1): 75-83.

Wardani, D.P., Arifin, M., Suharyadi, E., Abraha, K., 2015. Quantitative detection of bovine and porcine gelatin difference using surface plasmon resonance based biosensor, SPIE Optics+ Optoelectronics. Int. Society for Optics and Photonics, pp. 95060W-95060W-8.

Xu, M., Wei, L., Xiao, Y., Bi, H., Yang, H., Du, Y., 2017. Physicochemical and functional properties of gelatin extracted from Yak skin. Int. J. Biol. Macromol., 95: 1246-1253.

You, L., Regenstein, J.M., Liu, R.H., 2010. Optimization of hydrolysis conditions for the production of antioxidant peptides from fish gelatin using response surface methodology. J. Food Sci., 75(6):C582-7. Zhou, P., Mulvaney, S.J., Regenstein, J.M., 2006. Properties of Alaska pollock skin gelatin: a comparison with tilapia and pork skin gelatins. J Food Sci., 71(6): C313-C321.