KARAKTERISTIK PATI AREN HASIL BUTIRILISASI DAN POTENSI FUNGSIONAL RESISTANT STARCH-NYA
Abdul Rahim, STP., MP., Prof. Dr. Ir. Haryadi, M.App.Sc
2012 | Disertasi | S3 Ilmu PanganPati alami dari berbagai sumber pada umumnya memiliki sifat-sifat yang membatasi penggunaannya di dalam aplikasinya pada produk-produk pangan. Karena itu agar pati dapat diaplikasikan secara luas, maka perlu dilakukan perbaikan sifat fisik dan kimianya, antara lain dengan cara modifikasi pati. Penelitian tentang modifikasi pati telah banyak dilakukan hingga saat ini, akan tetapi pada umumnya penelitian tersebut hanya difokuskan pada upaya untuk memperbaiki sifat fisik dan kimia pati saja. Di sisi lain sesungguhnya modifikasi pati memiliki potensi yang besar untuk memberikan efek fungsional terhadap kesehatan orang yang mengkonsumsinya. Pati termodifikasi, terutama hasil modifikasi dengan cara esterifikasi, lebih tahan cerna dibandingkan pati alami yang menyisakan bagian pati tahan cerna (resistant starch, RS) yang kemudian memberikan efek yang menyehatkan terhadap kolon. Tujuan umum penelitian ini untuk peningkatan pemanfaatan pati aren, mendapatkan metode butirilisasi pati aren dan mengetahui potensi fungsional RS dari pati aren butirat untuk kesehatan. Tujuan khusus adalah (i) mengetahui faktor-faktor yang berpengaruh terhadap butirilisasi pati aren, (ii) mengetahui karakteristik fisik dan kimia pati aren butirat, (iii) mengetahui karakteristik fisikokimia RS dari pati aren butirat, dan (iv) mengetahui potensi fungsional RS dari pati aren butirat untuk keehatan secara in vitro. Penelitian ini terdiri atas empat tahap yaitu (i) sintesis pati aren butirat dari pati aren dengan parameter analisis persen butiril dan derajat substitusi (DS), (ii) karakterisasi fisik dan kimia pati aren butirat dengan parameter analisis pengikatan gugus butirat dengan fourier transform infrared (FT-IR), kristalinitas dengan X-ray diffractometer, water dan oil holding capacity (WHC, OHC), daya mengembang dan kelarutan, dan kadar RS, (iii) preparasi dan karakterisasi fisikokimia RS dari pati aren butirat dengan parameter analisis kadar gula reduksi, rendemen RS, dan struktur kimia RS dengan spektroskopi nuclear magnetic resonance (NMR), dan (iv) penentuan potensi fungsional RS dari pati aren butirat untuk kesehatan secara in vitro dengan parameter analisis WHC dan OHC, pengikatan asam/garam empedu, kolesterol, pertumbuhan bakteri, indeks prebiotik (IP), penurunan pH, produksi short chain fatty acid (SCFA), dan struktur kimia debutirilisasi gugus butirat dari RS dengan NMR. Hasil penelitian menunjukkan bahwa kondisi optimum sintesis pati aren butirat diperoleh dengan lama waktu reaksi 40 menit, pH dispersi 10 dan konsentrasi butirat anhidrida 15% dengan nilai DS tertinggi 0,226. Karakteristik pati aren butirat yaitu membentuk puncak baru pada spektra FT-IR pada bilangan gelombang 1728 cm-1 yang menunjukkan keberadaan gugus karbonil (C=O) dari gugus butiril, kristalinitas makin menurun seiring dengan meningkatnya DS namun tidak mempengaruhi tipe kristal molekul pati. WHC dan OHC pati aren butirat meningkat seiring dengan meningkatnya DS yang menyebabkan sifat hidrofilik dan hidrofobik meningkat. Daya mengembang meningkat, sedangkan xxiii kelarutan menurun seiring dengan meningkatnya DS. Kadar RS juga terlihat meningkat dengan meningkatnya DS. Preparasi RS dari pati aren butirat dengan menggunakan α-amilase dan amiloglukosidase masing-masing berlangsung selama 75 dan 45 menit. Rendemen RS dari pati aren butirat meningkat seiring meningkatnya DS. Struktur kimia RS dari pati aren butirat berdasarkan spektra 1H-NMR menunjukkan bahwa terbentuk puncak baru pada pergeseran kimia 0,83-0,85 ppm yang merupakan proton dari metil, dan 1,02-2,33 ppm yang merupakan proton dari metilen. Spektra 13C-NMR RS dari pati aren butirat terbentuk puncak baru pada pergeseran kimia 18,07-19,11 ppm merupakan karbon dari metil, 24,42-27,59 ppm merupakan karbon dari metilen, dan 165,61–175,11 ppm merupakan karbonil ester. Berdasarkan Spektra 13C-NMR RS dari pati aren butirat memiliki puncak yang lebih lebar pada atom C1 dan C6 dibandingkan dengan RS dari pati alami yang menunjukkan bahwa pengikatan gugus butiril terjadi pada atom C2 dan C6 pada satuan anhidroglukosa. Potensi fungsional RS dari pati aren butirat untuk kesehatan meliputi WHC dan OHC meningkat dengan meningkatnya DS, yang menunjukkan bahwa butirilisasi memperbaiki sifat hidrofilik dan hidrofobik pati aren butirat dan RSnya. Pengikatan asam atau garam empedu meningkat dan kadar kolesterol menurun seiring dengan meningkatnya DS. Potensi prebiotik RS dari pati aren butirat menunjukkan bahwa suplementasi RS pada fermentasi oleh bakteri kolon menghasilkan pertambahan jumlah sel Bifidobacteria dan Lactobacilli lebih tinggi daripada Bacteroides dan Clostridia. Nilai IP RS dari pati aren butirat pada lama waktu inkubasi 24 jam lebih tinggi daripada 48 jam. Aktivitas pertumbuhan bakteri kolon pada fermentasi RS memproduksi asam asetat, asam propionat, dan asam butirat yang menyebabkan pH media fermentasi menurun sampai 3,5 pada akhir fermentasi. Berdasarkan spektra 13C-NMR menunjukkan bahwa RS dari pati aren butirat yang difermentasi selama 48 jam mengalami debutirilisasi oleh bakteri kolon yang ditandai dengan terbentuknya puncak-puncak baru pada pergeseran kimia 13,99–18,73 ppm menunjukkan karbon dari metil, 20,19–39,83 ppm menunjukkan karbon dari metilen, dan 173,67–175,75 ppm yang merupakan gugus karbonil asam. Hal ini menunjukkan bahwa gugus butirat pada RS dari pati aren butirat dapat dilepas oleh esterase dari bakteri kolon menguntungkan sehingga konsentrasi asam butirat lebih tinggi dibandingkan dengan RS dari pati aren alami. RS dari pati aren butirat dapat dimanfaatkan oleh bakteri kolon dan berpotensi sebagai sumber baru prebiotik.
Native starch from various sources generally has disadvantaged properties, so will limit the usage in its food products application. To make it applied widely, it should be improved its physical and chemical properties. The physical and chemical properties improvement can be done by modifying the starch. The research of the modified starch was done up to now, however generally the previous researches just focus to improve the physical and chemical properties improvement. Actually, the starch modification not only able to improve its physical and chemical properties but give advantageous the functional effect on the health who consumed. Modified starch by esterification more were resisted to digestion than native starch that leaves of resistant starch to give the functional effect on the colon. The general purposes of this study were increased the utilization of arenga starch, to obtain the butyrylation method of arenga starches, and to know potential functional resistant starch (RS) from butyrylated arenga starches for health. The specific objectives of the research are (i) to know the factors of the effect on the butyrylation of arenga starch, (ii) to know physical and chemical characteristics of butyrylated arenga starches, (iii) to know functional characteristics of RS from butyrylated arenga starches, and (iv) to know the functional potential of RS from butyrylated arenga starches for health in in vitro. The research divided into four stages. The detail research stage as follows, (i) synthesis of butyrylated arenga starch from arenga starch with analysis parameters percent of butyryl and degree of substitution (DS), (ii) physical and chemical characterization of butyrylated arenga starch with analysis parameters binding of butyryl group by fourier transform infrared (FTIR), cristallinity by X-ray diffractometer (XRD), water and oil holding capacity (WHC, OHC), swelling power and solubility, and RS content, (iii) preparation, and physicochemical characterization of RS from butyrylated arenga starches with analysis parameters reduction sugar content, yield of RS, and chemical structure of RS by nuclear magnetic reconance (NMR) spectroscopy, and (iv) the determination functional potential of RS from butyrylated arenga starches for health in in vitro with analysis parameters WHC and OHC, acid / salts bile binding, cholesterol, bacterial populations changes, prebiotic index (PI), pH changes, short chain fatty acid (SCFA) production, and chemical structure of debutyrylated RS by NMR. The results showed that optimum condition synthesis of butyrylated arenga starches were achieved for 40 min with suspension pH 10 and butyric anhydride concentration at 15 % (starch basis) resulted in the highest DS (0.226). The FTIR profile indicated that the modification resulted in the butyryl group incorporation with the starch as shown by absorption of the ester carbonyl group (C=O) at band 1728 cm-1. XRD revealed that increasing DS was related to decreasing crystallinity. The WHC, OHC of butyrylated arenga starches increased with increasing DS indicating increase in both hydrophilicity and hydrophobicity of the starches. Swelling power increased, while solubility decreased with the xxv increasing DS. The RS derived from butyrylated arenga starches tended to increase with the increase of DS. Preparation of RS from butyrylated arenga starches with using α-amylase and amyloglucosidase for 75 and 45 min, respectively. Yield of RS from butyrylated arenga starches increase with the increase of DS. Chemical structure of RS from butyrylated arenga starches by 1H-NMR spectra it has been several new peaks chemical shifts at 0.80 to 0.85 ppm were identified as the protons of the methyl, and at 1.02 to 2.33 ppm were identified as protons of the methylene from butyryl groups. The 13C-NMR spectra RS from butyrylated arenga starches has been new peaks chemical shifts at 18.06-19.11 ppm were identified as carbon from methyl, 24.42-27.59 ppm were identified as carbon from methylene, and 165.61-175.11 ppm were identified as carbonyl carbon of butyryl groups. The 13C-NMR spectrum of the modified starches gave additional signals broadening of the C1 and C6 signals. Futher, results further suggested that the butyryl groups were substituted at the C2 and C6 positions at anhydroglucosa units. Functional potential of RS from butyrylated arenga starches for health such as WHC and OHC increased with increase in the DS, indicating that butyrylation increased both hydrophilicity and hydrophobicity of the starches and its resistant starches. The binding of bile acid/salts of RS from butyrylated arenga starches increased with the increase in DS and the cholesterol content decreased with the increasing DS. Prebiotic potential of RS from butyrylated arenga starches were indicated that the supplementation of RS to the batch fermenter resulted in a significant high increase in bifidobacteria and lactobacilli, whereas the bacteroides and clostridia populations slightly increase. The PI was calculated for RS after 24 and 48 incubation, higher PI scores were obtained after 24 h incubation. All RS were fermentable by gut microbiota as indicated increases in short chain fatty acid (SCFA) to produce such as acetate, propionate, and butyrate that reduction in the pH of media to 3.5. The chemical structure of RS from butyrylated arenga starches with DS 0.226 after 48 h incubation by human feces showed that the removal of signal starch backbone and butyryl groups as confirmed by 13C NMR spectra. Several additional signals at 13.99-18.73 ppm were assigned as the methyl carbon, at 20.19-39.83 ppm were assigned as the methylene carbon, and at 173.67-175.75 ppm were assigned as the carbonyl of butyryl acids. It was suggested that butyryl group in the RS from butyrylated arenga starches would be released by gut microbiota beneficial so that to production of butyric acid was higher than that of the RS from native arenga starch. In conclusion, the RS from native arenga starch and butyrylated arenga starches were fermented by gut bacteria and exhibited potential to be used a novel source of prebiotics.
Kata Kunci : pati aren butirat, sifat fungsional, derajat substitusi, resistant starch, prebiotik.
