Efeitos de diferentes processamentos sobre a qualidade nutricional e funcional de gr?os de milheto (Pennisetum glaucum (L.) R. Br.)

• Autor(a) principal: Martins, Amanda Mattos Dias
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/5028
• topic: Cereal; Gl?ten; Extrus?o; Aquecimento ?hmico; Cereal; Gluten; Extrusion; Ohmic heating; Ci?ncia e Tecnologia de Alimentos

Millet is the sixth most produced cereal in the world. In Brazil, although this crop is adapted to our agricultural conditions with about 5 million hectares planted, its production is destined only for animal feed and for plant cover (no-tillage). One reason for non-human consumption is possibly related to a lack of knowledge about the nutritional benefits and product types that can be made with the grain. Thus, the objective of this work was to promote knowledge about the technological and nutritional potential of millet grains (Pennisetum glaucum L.R.Br) to human consumption in Brazil and to evaluate the effects of different processing on the chemical, physical and nutritional properties of this cereal. The thesis was subdivided into three chapters, in Chapter I, an extensive bibliographical review was elaborated on millet grains in relation to food safety, nutritional composition, technological processes, health benefits and grain based products. In Chapter II, the effects of two methods of cooking, ohmic heating (OH) (emergent method) and open pan (conventional method) on yield, texture (TPA), color (C *, h ?, ?E), water absorption index (IAA), water solubility index (ISA) and pulp (RVA) properties of whole grains and decorticates. The results of the research showed that the optimal cooking time (OTC) of the whole grains and decorticated millet were 30 min and 20 min, respectively. OH did not promote faster grain cooking. Decortication impacted more on quality attributes than the applied heating method. In Chapter III, whole millet grains were submitted to five processing: decortication (10 min), cooking in open pan (98 ?C / 30 min), heating by oven heating (98 ?C / 30 min / 60 Hz), germination (30 ?C / 48 h) and extrusion (140 ?C / 600 rpm / double screw), and then processed into flours. The nutritional composition (proteins, lipids, dietary fiber, minerals) and functional properties (particle size distribution, absolute density, ISA, IAA, RVA) were evaluated. The results showed that crude millet flour has, on average in wet basis, 62.5% carbohydrates, 12.0% protein, 5.6% lipids, 8.2% dietary fiber, and minerals such as potassium, phosphorus and magnesium are the ones with the highest concentration. The results showed that the processed flours are nutritious and that decortication had a significant impact on the nutritional reduction of this food. Whole and decorticated raw flours have high viscosity and may be useful for making porridges. Germinated and extruded flours presented great nutritional advantages (retention of proteins and food fibers) and technological (such as high solubility, low viscosity), being potential ingredients for use in frozen foods and beverages. Flours cooked by both methods presented the same nutritional content as the raw flour and presented a high capacity of water absorption, being potential ingredients for the elaboration of gluten-free kibbeh or bread products. In general, millet grains, processed or unprocessed, can be considered as nutritious foods and depending on the process applied, may have varied applications in the development of products.