Efeito da pasteurização por aquecimento ôhmico nas características químicas, físicas e reológicas em bebida láctea de acerola

Abstract

Ohmic heating (OH) is an emerging thermal technology that consists of the passage of electric current in the food itself, promoting a rapid and homogeneous heating, due to the conversion of electric energy into thermal. Due to the rapid heating rate, the ohmic process presents advantages over conventional processes, such as: the higher maintenance of thermosensitive compounds, bioactive compounds, reduction of color degradation and the Maillard reaction products (MRP’s), important factors in product processing dairy products. In addition to the thermal effect of OH, there may be an additional non-thermal effect (electroporation) in the microbial cells, reducing the thermal resistance of microorganisms and the thermal intensity of the process. Thus, due to the rapid and homogeneous heating and the possible existence of electroporation, the OH presents as a promising technology for the development of dairy products. In this sense, the ohmic heating under different voltage conditions (45, 60 and 80 V - 60 Hz) and frequency (10, 100, 1000 Hz - 25 V) was applied to pasteurize whey acerola-flavoured drink in comparison to the conventional process , under the same temperature profile (65 °C/30 min), in order to evaluate the OH effect on physical and chemical and rheological characteristics. In general the results were directly affected by the treatment parameters. Low frequencies (≤ 100 Hz) and low voltages (< 45 V) resulted in lower degradation of ascorbic acid and beverage color; however, in relation to bioactive compounds, OH at 1000 Hz resulted in greater maintenance of phenolic compounds and peptides bioactive. OH may promote increase in beverage viscosity, similar lipid profiles with conventional processing, and lower formation of Maillard reaction products (PRM's) in the treatment at 45 V - 60 Hz. In general, OH may be an interesting option for processing of whey acerola-flavoured drink