Laser food processing has the breath-taking potential to revolutionize the industry in many aspects. Among the different laser configurations, CO₂ laser has received special attention due to its relative high efficiency in power generation, its high-power output and its laser beam wavelength, infrared, which is strongly absorbed by water, the main component of food materials. Over the last 50 years, different uses of CO₂ laser for processing foods have been proposed so far, including cooking, broiling and browning, selective laser sintering, marking, microperforation for improving downstream mass transfer operations (e.g. infusion, diffusion, marinating, salting, drying, extraction), cutting and peeling, and microbial surface decontamination. The present work is a review of the state of the art of the use of CO₂ laser for food processing that covers the main characteristics and mechanisms of this technology, as well as the most important published results regarding its applications in the agri-food sector, highlighting the main challenges to bring out its full potential in the coming years.

The use of microwaves (MWs) has been proposed as an energy-efficient method for reducing checking. Along with understanding moisture distribution, it is essential to consider structural characteristics to explain how MWs reduce checking. The influence of MWs on these characteristics depends on the food matrix’s dielectric and viscoelastic properties, which vary significantly between fresh and pre-baked dough. This study investigates the effects of MW treatment applied before (MW-O) or after conventional oven baking (O-MW) on low-fat biscuits that are prone to checking. Color (CIELab), thickness, moisture content and distribution, checking rate, texture, sensory properties, energy consumption and baking time were analyzed. The findings suggest that MWs reduce checking rate by eliminating internal moisture differences, while also changing structural properties, as evidenced by increased thickness and hardness. MW-O eliminated checking (control samples showed 100%) but negatively affected color, texture (increased hardness and breaking work), and sensory quality. The O-MW checking rate (3.41%) was slightly higher than in MW-O, probably due to the resulting different structural properties (less thickness, less hardness and breaking work). O-MW biscuits were the most preferred by consumers (54.76% ranked them first), with color and texture close to the control samples. MW-O reduced total energy consumption by 16.39% and baking time by 25.00%. For producers, these improvements could compensate for the lower biscuit quality. O-MW did not affect energy consumption but reduced baking time by 14.38%. The productivity improvement, along with the reduction in checking and the satisfactory sensory quality, indicates that O-MW could be beneficial for the bakery sector.