This work aimed to study the effect of three drying methods, namely sun-drying (SD) (T = 32 °C), continuous convective drying (CCD) (T = 35 ± 2 °C) and interval starting accessibility Drying (ISAD) (T = 35 ± 2 °C) with an active time of 30 s (t_on) and a tempering time of 60 s (t_off), on selected quality characteristics of a traditional dry-salted meat product known as “kaddid”. The analyses of chemical composition, lipid oxidation and fatty acid profile of kaddid were carried out before and after 45 days of storage (t = 0 vs. t = 45) at ambient temperature. Chemical composition and lipid oxidation (TBARS) of kaddid were affected by the drying methods. The CCD samples showed the lowest level of lipid oxidation. Protein content was better preserved via the ISAD method (7.27 g/kg DM). The fatty acid profile revealed the lowest mono-unsaturated fatty acid content in the ISAD samples; however, no significant difference was observed between the drying processes for the total poly-unsaturated fatty acid content. The storage period led to a significant decrease in the SFA values of CCD and ISAD samples against an increase in the MUFA ones. ISAD appeared to be a promising drying mode with a lower effective drying time and a good product quality preservation.

Infrared drying is increasingly used in the food industry. Infrared energy can improve drying operations and reduce energy consumption compared to convective drying. Often energy is lost during drying in the form of sensible energy, which increases the temperature of the sample and thus causes irreversible damage. Interval drying was applied to infrared by well-defined intervals. The new drying process IIRAD (Interval Infrared Airflow Drying) was implemented using infrared energy coupled with ambient temperature (18 ± 1 ◦C) airflow (1.41 m s ^{− 1}) drying and 0.7 W cm^{− 2} as IR power. In order to estimate the operating time intervals, the calculation of the energy necessary to evaporate a thin layer of water was estimated according to the initial moisture content. The intervals were then defined with 5s of action time (t_ON) and a tempering time (t_OFF) of 2 min. A second set of time related operating conditions was achieved by modulating t_ON during the drying process: constant t_OFF = 2 min while t_ON varied from (i) 5 s during the first 240 min (till water content reaches W = 4 g H₂O/g db), (ii) t_ON = 4 s during the next 273 min (till W = 2.6 g H₂O/ g db), and finally (iii) t_ON = 2 s till the end of the process. The three modes, continuous, IIRAD type I and II were compared through the drying kinetics, the effective drying time and the energy consumption. The moisture content rapidly decreased during IIRAD type I and II compared to continuous IR drying. The effective drying time was significantly reduced, which allowed a significant energy gain. The moisture migration from the deep layers to the surface of the samples mainly occurred during the tempering time, which accelerated the water evaporation during the following active times. Calculation and experimental tests showed that the energy required decreased throughout the drying process with water content decrease. Indeed, reducing t_ON from 5 to 2 s had a positive effect on drying since a higher evaporation rate was noted. Interval Infrared drying appears to be a promising method to intensify drying and save energy. The intervals must be defined according to the sample nature, the operating conditions and the water content of the sample which varies throughout the process.

Shrimp processing generates large amounts of byproducts such as shell, rich in valuable bioactive compounds, including proteins, lipids, minerals, and carotenoids. Their valorization into functional powders represents a sustainable approach for waste reduction and resource recovery. This study investigated the effects of three drying methods, namely sun drying, microwave drying, and convective air drying, on the drying kinetics and quality attributes of shrimp shell powder. The powders were evaluated in terms of antioxidant activity, chemical composition, and physicochemical and techno-functional properties, while structural and thermal characteristics were analyzed using FTIR and DSC techniques. The results showed that microwave drying significantly accelerated moisture removal (5.5 min), leading to the shortest drying time, whereas sun drying exhibited the slowest drying behavior (1680 min). Convective drying provided a balanced drying rate and better carotenoid levels (0.96 mg/g β-carotene equivalent against 0.916 and 0.714 mg/g for microwave and sun drying, respectively) and exhibited stronger antioxidant activity (IC₅₀ = 95.67 ± 1.62 μg/mL). Microwave drying ensured higher lipid retention (3.38%) but showed only moderate functional performance, while sun drying led to lower biochemical stability and changes in structural characteristics. In conclusion, convective drying offered the best compromise between drying efficiency and product quality, highlighting its potential for the sustainable valorization of shrimp byproducts.