Comparative Study on the Rice Bran Stabilization Processes: A Review

Abstract

Rice bran is an undervalued/underutilized by-product of rice milling, rich in protein, lipids, dietary fibers, vitamins, and minerals. It is an inexpensive source of high-quality protein, fiber and lipids to be incorporated into value-added food products. The issue with rice bran is its susceptibility to rancidity and therefore measures must be taken to stabilize the bran in order for it to be fully utilized. Due to this susceptibility to rancidity, historically the bran has either been disposed and wasted or used as low-grade animal feed. As the nutritional value of the bran has been recognized, along with its potential to add value to food products, research has been increasing in volume in order to determine the most effective methods for stabilizing the bran and extracting the valuable nutrients from it. It's been reported that a free fatty acid content of over 5% is considered to render the bran unfit for human consumption (Tao, Rao & Liuzzo, 1993). Therefore, controlling this level of rancidity is imperative to being able to store and use rice bran over extended periods of time. In order to achieve control, stabilization procedures can be carried out on the rice bran to slow down the lipase activity within the bran and preserve the nutritional qualities that rice bran possesses. Stabilization of rice bran is particularly important for use over winter months in developing countries, where there may be no crops to harvest and therefore a supply of non-rancid rice bran could be extremely beneficial. This length of storage for stabilized rice bran could be up to a period of 6 months, where it can become important for value-added product development (Bagchi, Adak & Chattopadhyay, 2014). The present review will provide an overview of the traditional and innovation rice bran stabilization techniques, those have been a common interest in the research community, and the suitability of the process in terms of the energy consumption.

Perbandingan Metode Stabilisasi pada Dedak Padi dengan Pemanasan Basah Berdasarkan Perolehan dan Karakteristik Fisiko-Kimia Minyak Dedak Padi

“…Rendemen minyak dari ekstraksi DP-SA lebih tinggi dibandingkan dengan DP-SP menandakan metode stabilisasi dedak padi dengan Autoklaf lebih efektif dalam menghambat aktivitas enzim lipase daripada metode Pengukusan Sederhana. Hal tersebut disebabkan suhu merupakan salah satu faktor penentu dalam menghambat aktivitas enzim lipase stabilisasi dengan perlakuan panas (Dubey et al, 2019). Suhu stabilisasi di atas 120 o C sampai pada batas tertentu (tergantung pada komposisi nutrisi yang diinginkan dalam dedak padi) dilaporkan merupakan suhu yang cocok untuk merusak enzim pendegradasi minyak tanpa merusak nutrisi yang terkandung di dalam Perubahan karakteristik fisik dari dedak padi selama proses penggilingan padi menjadi beras dan perbedaan perlakuan terhadap dedak padi, seperti kondisi penyimpanan dan perbedaan metode stabilisasi, berpengaruh signifikan terhadap aktivitas enzim-enzim di dalam dedak padi.…”

“…Selain itu, metode stabilisasi dedak padi dengan ekstruksi dilaporkan mengurangi kadar minyak dan protein dari dedak padi berturut-turut sebanyak 1,47% dan 43,33% (Rafe, Sadeghian, Hoseini-Yazdi, 2017). Sedangkan efektivitas stabilisasi dedak padi dengan autoklaf dan pengukus sebagai metode lain pada stabilisasi dedak padi dengan pemanasan basah dipengaruhi oleh berbagai faktor, misalnya kondisi operasi stabilisasi, tipe alat, dan efektifitas kontak antara uap air dengan butiran-butiran dedak padi (Dubey et al, 2019).…”

A short review of green extraction technologies for rice bran oil

“…Despite all of these attractive properties of rice bran, millions of tons of this by-product are wasted every year or employed as low-quality animal feeds [39]. This incredible waste of high-grade food is due to the instability of rice bran, and its tendency to become rancid because of its natural lipase enzyme that catalyzes the hydrolysis of oil into glycerol and free fatty acids [36].…”

“…Several techniques exist and have been studied for bran stabilization: these include parboiling, chemical methods, stove toasting methods, ohmic heating techniques, retained moisture heating, added moisture heating, dry heating under atmospheric pressure, extrusion cooking, microwave heating, and infrared heating. Many researchers agree that the most effective of the aforementioned methods is microwave heating, an inexpensive and fast method that generates a product with a low range of free fatty acid that remains stable over time [4,[38][39][40]. After stabilization, rice bran can be employed directly or can be subjected to other processes in order to obtain high-value products for food, nutraceutical or pharmaceutical industry applications.…”

Mechanism of rice bran lipase inhibition through fermentation activity of probiotic bacteria

“…Rice bran contains 10% of grain by weight. Each year, 63–76 million tons rice bran is produced in the world ( Dubey et al, 2019 ). A total of 15 to 20% of edible oil consumed in the United States come from Rice bran ( Kahlon, 2009 ).…”