Efficient Plant Foods Processing Based on Infrared Heating

Effects of infrared heating as an emerging thermal technology on physicochemical properties of foods

Infrared (IR) radiation is part of an electromagnetic spectrum between the ultraviolet and microwave regions. IR radiation impacts the surface of the food, generating heat that can be used as an efficient drying technique. Apart from drying, IR heating is an emerging food processing technology with applications in baking, roasting, microbial inactivation, insect control, extraction for antioxidant recovery, peeling, and blanching. Physicochemical properties such as texture, color, hardness, total phenols, and antioxidants capability of foods are essential quality attributes that affect the food quality. In this regard, the main objective of this review study was to highlight and discuss the effects of IR heating on food quality to expand its food applications and commercial adoption. The fundamental mechanisms, type of emitters, and IR processing parameters are discussed in this review to explore their impacts on food quality. Infrared heating has been shown that the appropriate operating conditions (distance, exposure time, IR power, and temperature) with high heat transfer, thus leading to a shorter drying time. Besides, IR heating used in food processing to improve food-surface color and flavor, it also enhances hardness, firmness, shrinkage, crispiness, and viscosity. Meanwhile, antioxidant activity is enhanced, and some nutrients are retained.

The retention and bioavailability of phytochemicals in the manufacturing of baked snacks

There is a growing body of evidence supporting the role that phytochemicals play in reducing the risk of various chronic diseases. Although there has been a rise in health products marketed as being "supergrains," "superfood," or advertising their abundance in antioxidants, these food items are often limited to powdered blends, dried fruit, nuts, or seeds, rarely intercepting the market of baked snacks. This is in part due to the still limited understanding of the impact that different industrial processes have on phytochemicals in a complex food matrix and their corresponding bioavailability. This review brings together the current data on how various industrial dehydration processes influence the retention and bioaccessibility of phytochemicals in baked snacks. It considers the interplay of molecules in an intricate snack matrix, limitations of conventional technologies, and constraints with consumer acceptance preventing wider utilization of novel technologies. Furthermore, the review takes a holistic approach, encompassing each stage of production-discussing the potential for inclusion of by-products to promote a circular economy and the proposal for a shift in agriculture toward biofortification or tailored growing of crops for their nutritional and post-harvest attributes.

Ultrasound, infrared and its assisted technology, a promising tool in physical food processing: A review of recent developments

Traditional food processing techniques can no longer meet the ever increasing demand for high quality food across the globe due to its low process efficiency, high energy consumption and low product yield. This review article is focused on the mechanism and application of Infrared (IR) and ultrasound (US) technologies in physical processing of food. We herein present the individual use of IR and US (both mono-frequency and multi-frequency levels) as well as IR and US supported with other thermal and non-thermal technologies to improve their food processing performance. IR and US are recent thermal and non-thermal technologies which have now been successfully used in food industries to solve the demerits of conventional processing technologies. These environmentally-friendly technologies are characterized by low energy consumption, reduced processing time, high mass-transfer rates, better nutrient retention, better product quality, less mechanical damage and improved shelf life. This work could be, with no doubt, useful to the scientific world and food industries by providing insights on recent advances in the use of US and IR technology, which can be applied to improve food processing technologies for better quality and safer products.

Vacuum and Infrared-Assisted Hot Air Impingement Drying for Improving the Processing Performance and Quality of Poria cocos (Schw.) Wolf Cubes

The objective of this study was to develop an efficient drying technology for poria cubes in order to improve product quality. Poria cubes were dried using different methods, including air impingement drying, infrared-assisted air impingement drying, vacuum drying, two-stage vacuum drying, and infrared-assisted air impingement drying. The results were compared with those from hot air drying. For the two-stage drying, the tested conditions were the first stage of vacuum drying with temperatures between 65–85 °C and a switching moisture ratio of 70–90%. The second stage infrared-assisted air impingement drying also had temperatures 65–85 °C. The drying kinetics (effective moisture diffusivity (D_eff), Biot number (Bi), and mass transfer coefficient (k) were studied via the product qualities (broken ratio, firmness, microstructure, and water-soluble polysaccharide content) and specific energy consumption (SEC) of the drying processes. The results showed that two-stage drying led to the lowest drying time and energy consumption, and also obtained the best qualities. Box–Behnken experimental design with response surface methodology (RSM) was used to optimize the two-stage operating conditions as 82 °C under vacuum drying until a moisture content of 81% and a temperature of 69 °C with infrared-assisted air impingement drying was achieved. These findings suggested that two-stage vacuum and infrared-assisted air impingement drying is a promising method for producing high quality and energy efficient dried poria cubes.

Investigating the Influence of Infrared Drying Method on Linden (Tilia platyphyllos Scop.) Leaves: Kinetics, Color, Projected Area, Modeling, Total Phenolic, and Flavonoid Content

The Linden (Tilia platyphyllos Scop.) is a highly popular herbal plant due to its central nervous system properties. In this study, thin layer drying kinetics of linden leave samples were experimentally investigated in an infrared (IR) dryer. In order to select the appropriate model for predicting the drying kinetics of linden leaves, eleven thin layer semi theoretical, theoretical, and empirical models, widely used in describing the drying behavior of agricultural products, were fitted to the experimental data. Moreover, the color, projected area (PA), total phenolic content (TPC), and total flavonoid content (TFC) were investigated. The results showed that the drying time decreased from 50 min to 20 min. with increased IR temperature from 50-70 °C. Therewithal, the Midilli model gave the most suitable data for 50 °C, 60 °C. Moreover, Verma et al. and Diffusion approximation models showed good results for 70 °C. The lightness and greenness of the dried linden leaves were significantly changed compared with fresh samples. The PA of dried sample decreased similar to the drying time. In addition, the drying temperature effect on the effective diffusion diffusivity (D_eff) and activation energy (E_a) were also computed. The D_eff ranges from 4.13 × 10^-12 to 5.89 × 10^-12 and E_a coefficient was 16.339 kJ/mol. Considering these results, the Midilli et al. model is above the 50 °C, 60 °C, and the Verma et al. and Diffusion to 70 °C, for explaining the drying behavior of linden leaves under IR drying. Moreover, it can be said that the Page model can be used, if it is desired, to express the drying behaviors, partially with the help of a simple equation material by drying. TPC and TFC values were statistically < 0.001 higher in dried samples compared to fresh samples; however, no change has been recorded of TPC and TFC values at different temperatures (50 °C, 60 °C, 70 °C).

The Effect of Infrared Drying on Color, Projected Area, Drying Time, and Total Phenolic Content of Rose (Rose electron) Petals

The effects of different drying temperatures (50, 60, 70 °C) on the quality of rose (Rose electron) petals were evaluated in this study. Drying time decreased from 1680 s to 600 s with increased infrared temperature. The temperature and time were increased from 50 °C to 70 °C and 30 min to 60 min, respectively, and a decrease in the fruit color quality was observed. The projected area (PA) of rose petals was affected significantly from temperature. After the drying process, the largest PA was observed as 33.35 cm² (50 °C, 30 min), while the smallest achieved at 70 °C, 60 min (27.96 cm²). Depending on the temperature values (50, 60, 70 °C), the average projection area of dry samples of the rose petals decreased 2.17 times compared to the projection area of fresh samples. The dried samples demonstrated an increase in the total phenolic (TP) content compared to the fresh samples. The maximum TP (44.49 mg GAE/g) was achieved at 45 min and 70 °C rose petals sample. The results concluded that infrared drying for 45 min at 70 °C could be recommended for drying rose (rosa electron) petals.