Gluten-free Products: Potential and Challenges of Thai Rice Bran

Asst. Prof. Dr. Saroat Rawdkuen

Gluten-free Products: Potential and Challenges of Thai Rice Bran

 

Nowadays, there is an increasing interest for gluten-free products as indicated by the number of paper published in ISI web of science (Figure 1). Increasing of the published papers related to “gluten-free” was observed every year (281 papers in 2010, 315 papers in 2011, 339 papers in 2012, and 177 papers up to 6 months of 2013). Moreover, the number of celiac patient grows is also the main reason for this interested.

Figure 1. Number of papers published in ISI web of science related to “gluten-free”

Source: http://apps.webofknowledge.com

 

Coeliac disease (CD) is a digestive tract disease that damages the small intestine and interferes with the absorption of nutrients from food (Figure 2). The ingestion of proteins present in some cereals such as wheat, rye and barley (Figure 3) causes a loss of the intestinal villi, leading to reduced nutrient absorption. CD has now become one of the most common lifelong disorders, affecting 1-2% of the population worldwide (Reilly and Green, 2012). Moreover, the number of patients has increased in the last several decades (Kawamura-Konishi et al., 2013). Individuals who have CD are unable to consume some of the most common products on the market, including breads and other food products made with wheat flour. The only way to overcome this problem is to follow a strict gluten-free diet throughout the life-span.

   The gut                                  http://healthyscrts.files.wordpress.com/2012/02/compare_wheat_rye_barley.jpg?w=470

   Figure 2. Human digestive tract                                                Figure 3.  Wheat, Rye and Barley

   Source: http://medical.cdn.patient.co.uk                                  Source: http://www.mayoclinic.com

 

Glutenin and gliadin are the major fraction of gluten (Figure 4) that play important role for gas retaining to obtain the desirable volume and texture in a dough system. The gluten is important not only for appearance, but also for crumb structure of cereal-based products (Figure 5). It is essential to form a strong protein network required for the desired viscoelasticity. Gluten removal results major problems for bakers, and the products are of low quality, exhibiting poor mouth feel and flavor (Gallagher et al., 2003). Gluten may be replaced by natural or synthetic raw materials which can significantly swell in water and form structural equivalent of gluten network in wheat dough. The most commonly used are hydrocolloids such as, xanthan, pectin, guar gum, Arabic gum, egg albumin, galactomannans, and methylcellulose.

gliadin glutenin gluten All About Gluten

Figure 4. Gluten molecule

      Source: http://www.precisionnutrition.com

 

 

Figure 5. Gluten-free breads with different rice bran sources and 2% albumen

Source:  Phimolsiripol et al. (2012)

 

Rice bran is an underutilized milling by-products of rough rice with 12-15% protein content, higher than any other portions of the rice kernel. Hundred kilograms of paddy rice will generate approx 5 to 10 kg of bran. Rice bran has a high nutritive value which containing a mixture of substances, including protein, fat, ash, and crude fiber. It is also considered as a source of hypoallergenic protein and dietary fiber (Abdul-Hamid & Luan, 2000). Besides proteins, rice bran is an excellent source of vitamins B and E. Bran also contains small amounts of anti-oxidants, which are considered to low cholesterol in humans (http://www.knowledgebank.irri.org).

Rice bran protein is an innovative all-natural source of premium vegetable protein, synbiotic fiber, and heart-healthy oil. It is gluten-free and hypoallergenic, contains not only vitamins and minerals, but also a wide variety of antioxidants and co-factors (Prakash, 1996). Rice bran protein also contains important amino acids (Lys, His, Arg, Thr, Gly, Cys, Val, Met, Isoleu, Leu, Tyr, and Phe: Table 1) needed for nutrition (Fabian and Ju, 2011). Furthermore, according to Wang et al. (1999), the amino acids in rice protein was better than casein and soy protein isolates in fulfilling the amino acid requirements for 2–5 years old children.

  Source: Fabian and Ju (2011).

Rice bran has been used in foods as full-fat rice bran, defatted rice bran, and in the form of rice bran oil and protein concentrates. Full-fat rice bran and defatted rice bran have been incorporated into many bakery products as well as other products such as protein supplements, binder ingredients for meat and sausage products, and raw material for the production of hydrolyzed vegetable proteins (Prakash, 1996). However, have only little information about using rice bran or rice bran protein isolates in gluten-free based products.

References

Abdul-Hamid A, Luan YS (2000). Functional properties of dietary fibre prepared from defatted rice bran. Food Chem. 68:15-19.

Cappa, C., Lucisano, M., Mariotti, M. (2013). Rheological properties of gels obtained from gluten-free raw materials during a short term aging. LWT - Food Sci. Technol. 53:464-472.

Fabian, C., Ju, Y.H. (2011).  A review on rice bran protein: its properties and extraction methods. Cri. Rev. Food Sci. Nutri. 51: 816-827.

Gallagher, E., Gormley, T.R., Arendt, E.K., 2003. Crust and crumb characteristics of gluten-free breads. J. Food Eng. 56: 153–161.

Kawanura-Konishi, Y., Shoda, K,. Koga, H., Honda, Y. (2013). Improvement in gluten-free rice bread quality by protease treatment. J. Cereal Sci. 58: 45-50. 

Mahmoud, R.M., Yousif, E.I., Gadallah, M.G.E., Alawneh, A.R. (2013). Formulations and quality characterization of gluten-free Egyptian balady flat bread. Ann. Agric. Sci. 58: 19.25.

Phimolsiripol, Y., Mukprasirt, A. , Schoenlechner, R. (2012). Quality improvement of rice-based gluten-free bread using different dietary fibre fractions of rice bran. J. Cereal Sci. 56: 389-395.

Prakash, J. (1996). Rice bran proteins: properties and food uses. Cri. Rev. Food Sci. Nutri. 36: 537-552.

Reilly, N.R., Green, P.H.R., 2012. Epidemiology and clinical presentations of celiac disease. Seminars in Immunopathology, 1-6.

Schoenlechner, R., Szatmari, M., Bagdi, A., Tomoskozy, S. (2013). Optimisation of bread quality produced from wheat and proso millet (Panicum miliaceum L.) by adding emulsifiers, transglutaminase and xylanase. LWT - Food Sci. Technol. 51: 361-366

Tang, S., Hettiarachchy, N.S., Shellhammer, T.H. (2002). Protein extraction from heat-stabilized defatted rice bran: physical processing and enzyme treatments. J. Agric. Food Chem. 50: 7444-7448.

Wang, M., Hettiarachchy, N.S., Qi, M., Burks, W., Siebenmorgen, T. (1996). Preparation and functional properties of buckwheat

           protein product. J. Agric Food Chem. 50: 2125-2129.

 

Asst. Prof. Dr. Saroat Rawdkuen (20-8-2013)

Event date: 
Tue, 2013-08-20 (All day)
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