Desenvolvimento e caracterização de farinhas mistas extrudadas de arroz e concentrado proteico de soro de leite bovino para a elaboração de biscoitos e mingaus

Abstract

Whey is one the most polluting by-products of the food industry and their perishability does not allow storage for long periods, then it's necessary to find appropriate destination. The whey protein have potential anticarcinogenic, activities hypocholesterolemic, anti-inflammatory, immunomodulatory action, among others. The rice consists mainly of starch, and this structure contributes to the production of snacks high technological quality. The objective of this study was develop and characterize mixed extruded flour of rice and whey protein concentrate aiming use in the manufacture nutritional and practical products. The parameters used in the processing of thermoplastic extrusion were: formulation (% whey protein concentrate), moisture content and temperature of the last heating zone. The extrudates were subjected to physical characterization and functional technology assessment. The highest rates of growth were observed for the tests with up to 4 % whey protein concentrates in their formulations and were processed with low humidity generally less than 20 % and milder temperatures, generally at or below 140 °C. Through the visual characterization of extruded and the micrographs it was observed that the samples processed with low moisture content (16.64 and 18%) were more homogeneous cells. The X-ray diffraction showed that the profile of the crystal samples is characteristic of type "A" due to the presence of crystalline domains in its structure. The flours viscosity profile is consistent with the characteristics of pre- gelatinized products, being dissolved without needing to cook. The pre-gel flour with blends of rice and whey protein concentrate present viscous, homogeneous and with low capacity of retrogradation. The addiction protein concentrate in rice flour increased the ash and proteins, indicating that the mineral and amino acid composition of the mixed flours may also have a nutritional improvement. Generally, the processing conditions do not significantly affect the nutritional value of the flours blends. The acceptance test performed with the cookies prepared with the mixed flours 8, 10 and 16 (6, 7.36 and 4 % whey protein concentrate, respectively) indicated that the biscuit with a higher content of protein concentrate showed better overall evaluation, taste and purchase intent. The porridges were produced with pre-gelatinized flour containing 2, 4 and 7.36% whey protein concentrate and sensory analysis evaluated the attributes appearance, flavor and consistency, plus purchase intent. The results showed that for most of the evaluated attributes and purchase intent, the sample with higher content of protein concentrate showed the best results. The porridges were produced with pre-gelatinized flour containing 2, 4 and 7.36% whey protein concentrate and sensory analysis evaluated the attributes appearance, flavor and consistency, plus purchase intent. The results showed that for most of the evaluated attributes and purchase intent, the sample with higher content of protein concentrate showed the best results. We conclude that it is possible to produce pre-gel flours containing rice and whey protein concentrate with good nutritional, microbiological and technological features for the production of cookies and porridges rapid dissolution.