Bioactive compounds in chocolate milk drink by cold plasma processing

Nowadays, due to the failures of conventional heat treatments associated with consumer demand, it has been stimulating the development of alternative approaches in non-thermal food processing. Atmosphere cold plasma (ACP) processing is emerging technologies that offer many potential applications in food industry. This study aims to evaluate the effect of the atmospheric cold plasma in bioactive compounds of chocolate milk compared to pasteurization treatment, through the analysis of DPPH (1,1-diphenyl-2-picrylhydrazyl) method, total phenolic content (TPC) and ACE inhibitory assay. ACP used was Plasma Etch PE-50 Venus type with 5, 10 and 15 min time variation and 10, 20 and 30 mL/min gas flow, totalizing 9 treatments (T1-T9). All experiment was performed at 400 W and 50 KHz power supply, at room temperature and using nitrogen gas. Pasteurization was at 65 °C/30 min (in laboratory). For the formulation of chocolate milk was 70 milk/ 30% whey (v/v). The mean values of DPPH, TPC, and ACE inhibitory activity of the chocolate milk drinks were 8.76 to 9.24 μg Eq. TE/g, 4.26 to 22.53 mg GAE/100 mL, and 7.11 to 13.75%, respectively. The present results indicate that milder processing conditions (lower gas flow rates and processing times) resulted in chocolate milk drinks with lower TPC and ACE inhibitory activity while maintaining the antioxidant activity similar to the pasteurized product. In the case of more severe processing conditions (higher gas flow rates and processing times), higher TPC and ACE inhibitory activity were observed, with a decrease in antioxidant activity (only for T9). The chocolate milk drinks subjected to intermediate ACP conditions exhibited bioactive compounds in the middle range and preservation of the antioxidant activity. The results demonstrated that the selection of the suitable cold plasma process parameters allows obtaining chocolate milk drinks with improved nutritional quality when compared to the pasteurized product, mainly concerning the ACE inhibitory activity. The mild (lower flow rate and process time) and more severe (higher flow rate and process time) conditions led to a reduction of the bioactive compounds. Intermediate ACP conditions an adequate concentration of bioactive compounds was observed. Overall, ACP technology has proven to be an interesting alternative to chocolate milk drinks, being of paramount importance the study of the cold plasma process parameters.