Estudo do efeito da desnaturação térmica e parcial das proteínas do leite de coco (cocus nucifera l.) na estabilidade física da emulsão

Abstract

Coconut milk is an oil-in-water emulsion stabilized by its proteins natural (globulins and albumins). Due to the low emulsifying capacity of its proteins, this emulsion quickly separates into a creamy layer and another relatively dense water. With separation, the milk takes on an appearance that consumer dissatisfaction, as they expect to see a product with a homogeneous, in such a way that the industry resorts to the use of external stabilizers to get around the problem. However, the addition of stabilizers not only involves costs processing fees (approximately $10/kg of stabilizer), such as can also cause health problems in consumers (inflammation gastrointestinal, for example) and, in some cases, the inefficiency of this method is observed to ensure complete stabilization. Recent studies indicate that denaturation Controlled heat can improve kinetic stability by forming a network three-dimensional droplets, which trap the continuous phase inside. It is in this sense that the present work seeks to study the effect of thermal denaturation and partial effect of proteins on the physical stability of the coconut milk emulsion, heat treatment of milk samples at different heating temperatures (40 at 120 oC, with increments of 10 oC per treatment for 30 minutes) followed by estimation of the denaturation interval by the CBB-G250 binding method, analysis of the effect of partial denaturation on the flocculation rate by microscopic observation, in coalescence by analyzing microscopic images with the aid of IC software Measure the sedimentation index and microstructure of the emulsion. Based on results obtained, it was found that coconut milk proteins (53.36% moisture, 34.73% lipids and 4.62% proteins) present a range of denaturation starting between 70 and 80 oC and ending between 110 and 120 oC; the increase in denaturation rate causes a decrease in the extent of phase separation (19.83% at 100 oC), slight coalescence (increase in 1.5 µm at 90 oC) and the increase in the rate of flocculation, which led to the formation of a three-dimensional network of droplets or floccules interconnected (particulate emulsion-gel) (TRADUÇÃO NOSSA).