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The effects of thermal (pasteurization and sterilization) and non-thermal (ultrasound and plasma) processing on the composition of prebiotic and non-prebiotic acerola juices were evaluated using NMR and GC-MS coupled to chemometrics. The increase in the amount of Vitamin C was the main feature observed after thermal processing, followed by malic acid, choline, trigonelline, and acetaldehyde. On the other hand, thermal processing increased the amount of 2-furoic acid, a degradation product from ascorbic acid, as well as influenced the decrease in the amount of esters and alcohols. In general, the non-thermal processing did not present relevant effect on juices composition. The addition of prebiotics (inulin and gluco-oligosaccharides) decreased the effect of processing on juices composition, which suggested a protective effect by microencapsulation. Therefore, chemometric evaluation of the H qNMR and GC-MS dataset was suitable to follow changes in acerola juice under different processing.

In this work, it is proposed a methodology which allows to differentiate a conventional and a specific transgenic common beans, grown in greenhouse or under field conditions, based on modifications in chemical composition using (1)H HR-MAS NMR. It is demonstrated that the influence of typical variables from field planting conditions had no significant influence on the ability to set apart transgenic from conventional. This methodology was corroborated by multivariate data analysis of the (1)H NMR and IR spectra. This study also points out the simplicity of using the HR-MAS NMR technique for food analyses. The measurement is highly simplified because it does not require any pretreatment of the sample apart from the addition of a small amount of D2O necessary to produce homogeneous dough and a field frequency lock. Moreover, due to the high concentration of the sample, measurement time in HR-MAS NMR is very short.

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