Revista Brasileira de Produtos Agroindustriais, Campina Grande, v.20, n.2, p.179-184, 2018 179 ISSN: 1517-8595 RICE HUSK USED AS A BREAD INGREDIENT Matheus Francisco da Paz1, Roger Vasques Marques2, Camilo Bruno Fonseca3, Lauren Andrade Vieira4, Luciara Bilhalva Corrêa5, Érico Kunde Corrêa6 ABSTRACT The rice husk corresponds to approximately one fifth of the grain mass and is usually a devalued byproduct. However, it presents a significant amount of insoluble fibers, which may favor its use as a source of fiber in the human diet. On the other hand, the insertion of these fibers into baking may drastically affect the technological characteristics of the breads. In this context, the objective of this experiment was to evaluate the loss of cooking mass, the color of the crust and the crumb, and the specific volume of bread with inclusion of different rice husk contents in its formulation. For this, the rice husk was previously dried, milled with a gram weight fixed at 0.5 mm and mixed in bread formulations with substitution of wheat flour by rice husk in the following proportions, respectively: T1 (100: 0), T2 (95: 5), T3 (90:10), T4 (85:15) and T5 (80:20). The experiment was performed in triplicate and the data processed statically. The results demonstrated that there was no difference of specific volume and loss of mass between the formulations. However, in relation to color, the parameter of luminosity was largely affected, with a marked decrease in both crust and crumb, since there was greater substitution of wheat flour by rice husks. Keywords: food security; insoluble fibers; solid waste; bakery; food quality. CASCA DE ARROZ USADA COMO INGREDIENTE DE PÃES RESUMO A casca de arroz corresponde a, aproximadamente, um quinto da massa do grão e, normalmente, é um subproduto desvalorizado. No entanto, apresenta quantidade significativa de fibras insolúveis, o que pode favorecer seu uso como fonte de fibras na dieta humana. Por outro lado, a inserção dessas fibras na panificação pode afetar, drasticamente, as características tecnológicas dos pães. Neste contexto, o objetivo neste experimento foi avaliar a perda de massa no cozimento, a cor da crosta e do miolo, e o volume específico de pão com inclusão de diferentes teores de casca de arroz em sua formulação. Para isso, a casca de arroz foi previamente seca, moída com gramatura fixada em 0,5 mm, e misturada em formulações de pão com substituição da farinha de trigo por casca de arroz nas seguintes proporções, respectivamente: T1 (100:0), T2 (95:5), T3 (90:10), T4 (85:15) e T5 (80:20). O experimento foi realizado em triplicata e os dados processados estaticamente. Os resultados demonstraram que não houve diferença de volume específico e perda de massa entre as formulações. No entanto, em relação à cor, o parâmetro de luminosidade foi amplamente afetado, com decréscimo acentuado tanto da crosta quanto do miolo, já que houve maior substituição de farinha de trigo por casca de arroz. Palavras-chave: Segurança alimentar, fibras insolúveis, resíduo sólido, padaria, qualidade dos alimentos 1 Químico de Alimentos, Mestre e Doutor em Ciência e Tecnologia de Alimentos, UFPel. Rua Benjamin Constant, 989, sala 200, CEP 96010-020, Pelotas – RS. E-mail: [email protected] 2 Professor Dr. do IFSul – Campus Bento Gonçalves, Bairro Juventude da Enologia, CEP 95700-206, Bento Gonçalves – RS. E-mail: [email protected] 3 Tecnólogo em Agroindústria, Mestre em Ciência e Tecnologia de Alimentos, UFPel. Rua Benjamin Constant, 989, sala 200, CEP 96010-020, Pelotas – RS. E-mail: [email protected] 4 Bacharela em Ciência e Tecnologia de Alimentos, Mestra em Ciência e Tecnologia de Alimentos, UFPel. Rua Benjamin Constant, 989, sala 200, CEP 96010-020, Pelotas – RS. E-mail: [email protected] 5 Professora Dra., Departamento de Engenharia Ambiental e Sanitária, UFPel. Rua Benjamin Constant, 989, sala 200, CEP 96010-020, Pelotas – RS. E-mail: [email protected] 6 Professora Dra., Departamento de Engenharia Ambiental e Sanitária, UFPel. Rua Benjamin Constant, 989, sala 200, CEP 96010-020, Pelotas – RS. E-mail: [email protected] 180 Rice husk as an ingredient in bakery Paz et al. INTRODUCTION capacity of gluten formation, a heterogeneous mixture of protein, especially gliadin and Important in the economic and social glutenin, responsible to form a web of protein point of view and innutrition combat, the rice that retain the gas produced for yeast in contributes to food security. It is estimated that fermentation process (Pallarés et al., 2007; in the 2050 year, the planet population will Damodaran et al., 2010). reach the mark of 9 billion people, demanding In this context, it is interesting the that the food production be duplicated in addition of different fiber sources in relation to the produced nowadays (Godfray et formulation of breads and evaluate not only in al., 2010). relation to the decrease of volume, as the other The rice grain is constituted by a extern characteristics which this addition will imply layer named husk, with a great quantity of technologically in the final product (Ragaee et insoluble fiber, corresponding in an average of al., 2011). Among these characteristics, it is 19% of grain weight (Ludueña et al., 2011), it important to detach the importance of has as well the bran that represents acceptance from the coloration (Francis, 1995). approximately 10% of the weight (Tanaka et In bakery, the pigment formation presents al., 2006), and, lastly, the polished grain, which complex mechanisms, but, in general, is has higher starchy and nutritive character, characterized by Maillard and caramelization corresponding to the 71% remained (Mohd reactions, influenced mainly by the type and fairulnizal et al., 2015). quantity of carbohydrates, proteins and amino The national production of rice has been acids (Trevisan et al., 2016; Tas & Gokmen, growing in the recent years. Just in Brazil, in 2017). Moreover, the dietary fibers have 2016/2017 crop the harvest resulted in 12.3 properties of water retention in food matrix million ton of grain (CONAB, 2017), which (Gray, 2006). It should be noted that the water corresponds to a husk production of retention capacity in the product can affect the approximately 2.3 million ton. This becomes an bread weight, its perishability and shelf life (Fu environmental problem, because in production & Labuza, 1993). countries, its quantity is plentiful, being needed Therefore, the aim of this study was to a widely storage space (Chandrasekhar et al., evaluate the effect of rice husk inclusion as a 2003), exceeding the capacity of adequate substitute in wheat flour on bakery properties. production places. The burn of husk in open sky results in MATERIALS AND METHODS gas generation which can contribute to climate changes (Johar et al., 2012), setting a The rice husk (Oryza sativa L) was detachment of sustainability perspective in rice obtained in a laboratory benefit machine of the agro industry (Daifullah et al., 2002). postharvest processing, with 8.6% of moisture The husk fibers has an average of 32% of measurement in thermobalance IV Eurotherm cellulose, 21% of hemicellulose, 21% lignin mark Gibertini, dried in stove at 105°C for 24 and 26% composed of other fibers (Rahman & hours, resulting in 0.8% moisture, in order to Ismail, 1993). The fibers are nutritional facilitate the grinding process. important, keeping the good functioning of The husk was grounded by slicer Perten gastrointestinal tract, due to its probiotic effect, and elapsed in sieve of 0.5mm gram weight. increase of satiety, obesity combat and others The other ingredients were purchased in local (Damodaran et al., 2010). However, studies trade and weighed on analytical balance, indicated that when added to bakery products respecting the following formulations, tend to worsen some bread characteristics according to Table 1. (Ragaee et al., 2011; Wang et al. 2002), causing The treatments realized were T1 (100% principally for gliadins and glutenins dilution wheat flour), T2 (95:5), T3 (90:10), T4 (85:15) (Damodaran et al., 2010). e T% (80:20) of wheat flour:rice husk, In bakery, wheat is more commonly used respectively. The ingredients were mixed by for its unique characteristics giving to the direct mass technique in bakery Cadence model products. In a mixture with water, it forms a PAD530, following methodology adapted from cohesive and tenacious mass, capable of retain Kadan et al. (2001), where all the ingredients gas and giving origin to light and aerated are disposal in the baker and it is realized the products after the cooking process (Pallarés et conventional cycle indicated by the producer, al., 2007). This property is given for the taking into consideration the quantity of Revista Brasileira de Produtos Agroindustriais, Campina Grande, v.20, n.2, p.179-184, 2018 Rice husk as an ingredient in bakery Paz et al. 181 presented mass. Analysis of loss weight when evaluated were divided into groups, being baked was executed following methodology physical characteristics (loss weight when proposed by Moore et al. (2006), where the baked; specific volume), and colorimetric mass was weighed before and after the baking, profile (parameters L and Hue angle). The given by the difference and expressed in outliers were identified with the plot residual percentage. studentized externally (Rstudent) versus predicted values (variable Y) and removed from Table 1. Formulations used on the experiment database. The data obtained had its normality analyzed by Shapiro-Wilk test, the samples Ingredients Quantity1 Real % homocedasticity by Hartley test and the independence of the residues by graphical Wheat flour: Rice husk 100g 57.8 analyses. The variables were normalized and Sugar 5g 2.9 submitted to analyses of variance by F test Salt 2g 1.2 (p<0.05). Yeast 3g 1.7 Ascertaining statistical significance, the data were evaluated by linear regression with Soybean oil 3g 1.7 adjustment to linear models (crust luminosity; Water 60g 34.7 specific volume) and quadratic (crust °Hue; Total 173g 100% crumb °Hue; crumb luminosity) using the 1 Based in flour weight Equations 2 and 3.