Infrared (IR) technology is highly energy-efficient, less water-consuming, and environmentally friendly compared to conventional heating. Further, it is also characterized by homogeneity of heating, high heat transfer rate, low heating time, low energy consumption, improved product quality, and food safety. Infrared technology is used in many food manufacturing processes, such as drying, boiling, heating, peeling, polyphenol recovery, freeze-drying, antioxidant recovery, microbiological inhibition, sterilization grains, bread, roasting of food, manufacture of juices, and cooking food. The energy throughput is increased using a combination of microwave heating and IR heating. This combination heats food quickly and eliminates the problem of poor quality. This review provides a theoretical basis for the infrared treatment of food and the interaction of infrared technology with food ingredients. The effect of IR on physico-chemical properties, sensory properties, and nutritional values, as well as the interaction of food components under IR radiation can be discussed as a future food processing option.

The effect of infrared radiation (IR) on the physicochemical characteristics, pectin methylesterase activity (PME), hydroxymethylfurfural (HMF) content, microbiological activity, color, and sensory aspects on black lime juice was studied. IR was compared to conventional thermal heating (CTH) in batch infrared extraction pasteurizer, designed to allow both infrared and conventional heating. IR resulted in a reduction in pH and Brix values and a mild increase in titratable acidity, as compared to CTH and control. After 60 days at 5 °C, the ascorbic acid percentage was decreased by 24.90%, 29.75%, and 58.31% in the control, IR and CTH, respectively. The total amount of phenols in juice treated with IR was higher as compared to CTH and control, while there was a significant decrease in the antioxidant activity. The statistical analysis reflected significantly low (p < 0.05) activity of PME for IR samples as compared to CTH and control. The amount of Hydroxymethylfurfural (HMF) in all juice samples steadily increased during the storage at 5 °C in 60 days. The microbial content of control was 3.85 log cfu/mL after 60 days at 5 °C, while it was 2.1 log cfu/mL for IR which reflected a significant difference between the IR, CTH, and control samples. Additionally, color and sensory analysis of IR treated sample when compared to control, reflected similar attributes. Overall, IR was found to be an excellent substitute for the preservation of black lime juice as a rapid pasteurization technique with less heat exposure; wherein the nutrition and health benefits of the juice could be maintained for a minimum period of 60 days.

Infrared irradiation is an alternative method for the thermal processing of foods. Lime is one of the citrus fruits and considered beneficial for human health. Dried lime juice is common in the Middle Eastern region and alternatives are desired to the conventional resistance heating method for the elimination of undesirable microorganisms. A batch infrared extraction pasteurizer (BIREP) was developed to test both infrared and conventional heating methods. Dried lime juice was treated in the BIREP using combinations of temperature (60, 75, and 90°C) and power output (350, 525, and 700 W) from infrared bulbs using a central composite design. Samples were subsequently analyzed for dependent variables of ascorbic acid content, total phenolic content, antioxidant activity, pectin methylesterase, hydroxymethyl, total plate counts, lightness, redness, and yellowness. Each combination of temperature and power was also quantified for specific infrared energy consumption, energy efficiency, and productivity. BIREP temperature and power settings were optimized for all dependent variables. The resulting optimized settings were used to process another set of dried lime juice samples. These samples were compared to control (untreated) and conventional heating samples. Sensory (appearance, aroma, taste, and overall acceptability) evaluation was conducted by a panel of humans. Infrared processing was superior to conventional processing and equivalent to control samples in all four sensory tests. The results indicated strong potential for infrared processing as a superior alternative to conventional heating for the preservation of dried lime juice. Practical applications Infrared heating offers a safe alternative to conventional resistance heating that equals or improves the consumer-desired characteristics compared to fresh dried lime juice and provides a marked improvement over conventional heating. This may allow infrared processed juice to warrant a price premium over conventional thermal processing. Since dried lime producers typically thermally process their juice using the batch method, they can switch to infrared heating to improve the quality of their processed juice and promote the resulting benefits. Cost-benefit studies would be appropriate for dried lime juice processers to evaluate the conversion of thermal processing to infrared heating to take advantage of the superior product. How to cite this article: Aboud SA, Altemimi AB, Al-Hilphy ARS, Watson DG. Effect of batch infrared extraction pasteurizer (BIREP)-based processing on the quality preservation of dried lime juice.