TEPUNG KACANG MERAH (Phaseolus vulgaris L.) PRATANAK: PENINGKATAN PATI RESISTEN, KARAKTERISASI SIFAT FUNGSIONAL DAN PENGARUHNYA TERHADAP PROFIL LIPID SERTA BAKTERI KOLON PADA MODEL HEWAN COBA

WALUYO, Prof. Dr. Ir. Y. Marsono, MS.

2021 | Disertasi | DOKTOR ILMU PANGAN

Kacang merah merupakan leguminosae dengan kadar karbohidrat tertinggi, berpotensi sebagai sumber pati resisten (RS). RS terbukti baik bagi berbagai fungsi fisiologi tubuh, salah satunya sifat hipokolesterolemiknya mampu menurunkan kolesterol darah. Pemanfaatan kacang merah masih terbatas karena pengolahannya memerlukan waktu yang lama. Masalah tersebut dapat diatasi dengan pengolahan tepung kacang merah pratanak. Tepung yang dihasilkan tinggi RS, umur simpan lebih lama, mudah dicampur, mudah dibentuk dan lebih aplikatif. Pratanak dengan metode kombinasi pemanasan-pendinginan merupakan salah satu upaya peningkatan kadar RS yang bersifat ramah lingkungan. Beberapa penelitian pratanak tepung kacang merah pernah dilakukan tetapi kadar RS belum optimal. Penelitian kacang merah kebanyakan masih berbasis pati, meskipun pati kacang-kacangan jarang dikonsumsi dengan sendirinya. Tujuan penelitian untuk mendapatkan tepung kacang merah pratanak tinggi RS melalui metode kombinasi pemanasan-pendinginan yang memiliki efek hipokolesterolemik dan perbaikan bakteri kolon . Kacang merah diperoleh dari pasar tradisional di Magelang, Jawa Tengah, Indonesia. Penelitian meliputi 3 tahap, yaitu: 1) pengolahan tepung kacang merah pratanak metode kombinasi pemanasan-pendinginan, dengan perlakuan: (i) steamingpendinginan 3 siklus (SSS), (ii) steaming-pendinginan, oven mikrowave-pendinginan, autoclaving-pendinginan (SMA) dan (iii) steaming-pendinginan, autoklavingpendinginan, oven microwave-pendinginan (SAM). Pengukusan selama 30 menit mendidih, microwave 2450 Hz, 900 W selama 4 menit dan autoclaving 121°C, 15 Atm, 145 detik; 2) uji in vivo (sifat hipokolesterolemik, karakteristik digesta sekum, komposisi SCFA dan bakteri kolon) dan 3) uji in vitro (kapasitas pengikatan asam empedu). Uji in vitro dan in vivo menggunakan dua jenis diet, yaitu diet tepung kacang merah alami (HTN) dan diet tepung kacang merah pratanak (HTM). Pada uji in vivo disiapkan pakan isokalori & isoprotein untuk 2 kelompok tikus SD yaitu kelompok yang diberikan diet HTN & HTM. Tikus sehat dengan diet standar AIN 93 (NPS), tikus hiperkolesterol dengan diet standar (HPS) dan tikus hiperkolesterol dengan diet standar dengan pengobatan statin (HPV). Hasil penelitian diperoleh tepung kacang merah pratanak SMA menghasilkan kadar RS paling tinggi dibandingkan SSS dan SAM. Berturut-turut peningkatan kadar RS 116,10%bk; 89,62%bk dan 86,05%bk. Perlakuan menyebabkan menurunnya daya pembengkakan, daya pengikatan air, daya pengikatan minyak, kelarutan, dan sifat pasting serta merubah struktur mikroskopis. Scanning electron microscopy menunjukkan serpihan-serpihan granula pati mengarah hilangnya tampilan granular, permukaan kasar, memiliki bentuk yang tidak beraturan, ukuran lebih besar dan heterogen. Analisis X-ray diffraction menunjukkan semua perlakuan tepung kacang merah memiliki kristalinitas tipe C. Pengujian in vitro diperoleh bahwa kapasitas pengikatan asam empedu lebih signifikan pada diet HTM dibandingkan diet HTN, dengan peningkatan pengikatan asam kolat 13,61% dan asam deoksi kolat 48,02%. Pengujian in vivo kelompok HTM, dapat memperbaiki profil lipid tikus dislipidemia, dengan penurunan TC, LDL, TG berturut-turut 43,66%; 57,8% dan 16,92% serta dapat meningkatkan HDL 171,61%. Sedangkan AIP turun hingga 78,65%. Diet HTM dapat meningkatkan total SCFA sebesar 152,43% dan asam propionat 155,29%. Diet HTMxix dapat meningkatkan komposisi jumlah Bifidobacterium, spp dan Lactobacillus, spp serta menurunkan jumlah bakteri E. coli. Perbaikan profil lipid diet HTM pada tikus dislipidemia melalui mekanisme: (1) penghambatan absorbsi kolesterol, (2) peningkatan ekskresi asam empedu, (3) peningkatan asam propionat dalam digesta, atau gabungan dari ketiga mekanisme tersebut. Perbaikan bakteri kolon melalui mekanisme adhesi fisik Bifidobacterium pada RS dan fermentasinya menghasilkan energi memodulasi pertumbuhan bakteri probiotik, kondisi asam menekan pertumbuhan bakteri patogen. Tepung kacang merah pratanak (SMA) menghasilkan RS paling tinggi. Diet HTM mampu mampu memberikan efek perbaikan profil lipid dan memperbaiki bakteri kolon yang lebih baik dari diet HTN pada tikus dislipidemia. Kata kunci: tepung kacang merah, pratanak, kombinasi pemanasan-pendinginan, hipokolesterolemik, profil lipid, bakteri kolon.

Red beans are legumes with the highest carbohydrate content potentially as a source of resistant starch (RS). RS is proven to be beneficial for various physiological functions of human body, specifically its hypocholesterolemic properties which can reduce blood cholesterol. The use of red beans is still limited because of the long time processing. These problem can be overcome by processing as pregelatinization red bean flour. The resulting flour is high in RS, longer shelf life, easy to mix, easy to shape and more applicable. Pregelatinization with the combined heating-cooling method is one of the efforts to increase the level of RS which is environmentally friendly. Several studies of pregelatinized red bean flour have been carried out but RS levels have not been optimal. Most red bean research is still starch-based, although legume starch is rarely consumed on its own. Therefore, this study aimed to obtain RS high pregelatinized red bean flour through modified heating-cooling combine process that had a hypocholesterolemic effect and improved composition of the colonic bacteria. Red beans were obtained from traditional markets in Magelang, Central Java, Indonesia. The research consisted of 3 stages, namely: 1) processing of pregelatinization red bean flour with a combination heating-cooling method, with the treatment: (i) steaming-cooling 3 cycles (SSS), (ii) steaming-cooling, oven microwave-cooling, autoclaving-cooling (SMA) and (iii) steaming-cooling, autoclaving-cooling, oven microwave-cooling (SAM). Steaming for 30 minutes boiling, microwave 2450 Hz, 900 W for 4 minutes and autoclaving 121 °C, 15 atm, 145 seconds; 2) in vivo test (hypocholesterolemic properties, characteristics of cecum digesta, SCFA composition and colonic microbiota composition)and 3) in vitro test (bile acid binding capacity) RS high red bean flour. In vitro and in vivo tests used two types of diets, which consisted of a natural red bean flour (HTN) diet and a modified red bean flour (HTM) diet. In the in vivo test, isocalories & isoprotein feeds were prepared for 2 groups of SD rats, namely the group given the HTN & HTM diet. Healthy rats on a standard diet AIN 93 (NPS), hypercholesterolemic rats on a standard diet (HPS) and hypercholesterolemic rats on a standard diet with statin treatment (HPV). The results showed that red bean flour pregelatinized SMA produced the highest RS content compared to SSS and SAM. Successively increasing levels of RS 116.10%db; 89.62%db and 86.05%db. This modified treatment resulted in decreased swelling, WHC, OHC, solubility, and pasting properties and changed the microscopic structure. Scanning electron microscopy showed flakes of starch granules leading to loss of granular appearance, rough surface, irregular shape, larger size and heterogeneity. Xray diffraction analysis showed that all red bean flour had type C crystallinity. In vitro testing showed that the binding capacity of bile acids was more significant the HTM diet than the HTN diet, with an increase in the binding of cholic acid 13.61% and deoxy cholic acid 48.02%. In vivo testing of the HTM group, it could improve the lipid profile of dyslipidemic rats, with a decrease in TC, LDL, TG, respectively 43.66%; 57.8% and 16.92% and could increase HDL by 171.61%. Meanwhile, IA decreased to 78.65%. HTM diet could increase the total SCFA by 152.43% and propionic acid 155.29%. The HTM diet could increase the composition of Bifidobacterium, spp and Lactobacillus, spp and reduce the number of E. coli bacteria. The mechanism for improving the lipid profile of HTM diet in dslipidemic rats was proven by: (1) inhibition of cholesterol absorption, (2) increased excretion of bile acids, (3) increased propionic acid in digesta,xxi or a combination of the three mechanisms. The improvement of colonic bacteria composition through the physical adhesion mechanism of Bifidobacterium to the RS and its fermentation produces energy modulating the growth of probiotic bacteria, acidic conditions suppress the growth of pathogenic bacteria. Pregelatinized red bean flour (SMA) produced the highest RS compared to other modifications and natural red bean flour. The HTM diet provided a better lipid profile repair effect than the HTN diet and could improve the colonic microbiota composition of dyslipidemic rats. Keywords: red bean flour, pregelatinization, heating-cooling combination, hypocholesterolemic, lipid profile, colonic bacteria.

Kata Kunci : tepung kacang merah, pratanak, kombinasi pemanasan-pendinginan, hipokolesterolemik, profil lipid, bakteri kolon.