Effect of thermal and non-thermal techniques for microbial safety in food powder: Recent advances

Microwave Treatments of Cereals: Effects on Thermophysical and Parenchymal-Related Properties

Dielectric heating is one of the most interesting techniques for pest disinfestation. However, most of the literature works give information about the ability of microwave treatments at different power-time conditions to kill insects; less is given about the analysis of matrices structural properties and heat transport. Accordingly, the aim of this work is to investigate the effect of microwave treatments, applied for pest disinfestation, on heat transport behavior and physical/structural properties, such as water uptake capability, mineral losses, texture change, and germination capability, of most consumed cereals in human diet, such as weak wheat, durum wheat, and corn. Two different radiative treatments were performed: one in time-temperature conditions capable of inactivating the weed fauna, and the other at high temperatures of ~150 °C, simulating uncontrolled treatments. Heat transport properties were measured and showed to keep unvaried during both effective and uncontrolled microwave treatments. Instead, grain physical properties were worsened when exposed to high temperatures (reduction of germination ability and texture degradation). The achieved results, on the one hand, provide new structural and heat transport data of cereals after microwave treatments, actually not present in the literature, and on the other, they confirm the importance of correctly performing microwave treatments for an effective disinfestation without affecting matrices physical properties and nutritional features.

An integrated analytical approach based on NMR, LC-MS and GC-MS to evaluate thermal and non-thermal processing of cashew apple juice

Innovative chemometric approaches by NMR and LC-MS data fusion (multiblock analysis) and decomposition of the GC-MS raw data by PARADISe were applied to evaluate the influence of thermal and non-thermal processing on the composition of cashew apple juices. Comparative investigations by Principal Component Analysis (PCA) highlighted pronounced effect of thermal processing on juice compared to non-thermal processing, as decreases of anacardic acids, sucrose, malic acid, tyrosine, phenylalanine, and important flavor compounds (esters, aldehydes, and ketones). Ultrasound presented relevant influence on increase of anacardic acids concentration. Non-thermal processing carried out at more intense conditions (10 min of ultrasound, 5 min of ozone, and pulsed light at 10 V) showed pronounced effect compared to other non-thermal processing. Although individual PCA enables to detect the influence of different processing technologies, data fusion and PARADISe presented advantages, since a more comprehensive understanding of the relationship among chemical changes from different analytical techniques were established.