Use of Cold Plasma To Inactivate Escherichia coli and Physicochemical Evaluation in Pumpkin Puree.

This work aimed to study the pumpkin puree processing by cold plasma corona discharge as an alternative to heat treatment to reduce Escherichia coli contamination and evaluate physicochemical alterations, using argon (Ar) as the process gas. The treatment time to verify E. coli inactivation was between 2 and 20 min, while physicochemical alterations were analyzed at 5, 10, 15, and 20 min. Cold plasma corona discharge technology to inactivate E. coli proved to be promising, reaching 3.62 log cycles of reduction at 20 min of treatment. The inactivation kinectics showed a tendency of higher decrease with time. Physicochemical characteristics indicate that plasma induces a decrease of pH; however, there is an indication that process gases have an important role and react with the environment and procedure reactive species. This technology may reduce the total carotenoid content of pumpkin puree and in color, mainly the a* parameter, which showed great reduction.

Biodiesel production using fatty acids from food industry waste using corona discharge plasma technology.

This article aims to describe an alternative and innovative methodology to transform waste, frying oil in a potential energy source, the biodiesel. The biodiesel was produced from fatty acids, using a waste product of the food industry as the raw material. The methodology to be described is the corona discharge plasma technology, which offers advantages such as acceleration of the esterification reaction, easy separation of the biodiesel and the elimination of waste generation. The best conditions were found to be an oil/methanol molar ratio of 6:1, ambient temperature (25 °C) and reaction time of 110 min and 30 mL of sample. The acid value indicates the content of free fatty acids in the biodiesel and the value obtained in this study was 0.43 mg KOH/g. Peaks corresponding to octadecadienoic acid methyl ester, octadecanoic acid methyl ester and octadecenoic acid methyl ester, from the biodiesel composition, were identified using GC-MS. A major advantage of this process is that the methyl ester can be obtained in the absence of chemical catalysts and without the formation of the co-product (glycerin).