Application of radiofrequency heating and low humidity air for sequential drying of apple slices: Process intensification and quality improvement. (January 2021)

• Record Type: Journal Article
• Authors: Shewale, Sandhya R.; Rajoriya, Deependra; Bhavya, M.L.; Hebbar, H. Umesh
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 135(2021)
• Publication Date: 2021-01
• Subjects: Drying kinetics -- Polyphenols -- Volatile -- Energy -- Microstructure; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2020.109904
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: The present study aims at developing a low-temperature energy-efficient sequential drying approach, using radiofrequency (RF) waves and low humidity air (LHA) for heat-sensitive foods like apple. Efficacy of employing RF at primary (RF + LHA) and secondary (LHA + RF) drying stage with LHA was studied in comparison with LHA and HA (hot air) and RF (2 A) drying, individually at 40 °C. LHA + RF reduced the drying time by 37% and energy consumption by 52% compared to LHA. Apple slices dried with sequential LHA + RF approach well preserved the polyphenols (98%), flavonoids (87%), and ascorbic acid (77%) compared to FD. Sequential drying did not affect the color (ΔE = 7.4 ± 0.7) and also improved the rehydration ratio (3.9 ± 0.1). The principal component analysis demonstrated that LHA + RF had higher retention of volatile compounds (aldehydes, esters, acids, alcohols) than other studied methods. The study suggests that the application of RF at the secondary drying stage with LHA accelerates the drying process and reduces energy requirement with better retention of product quality attributes. Graphical abstract: Image 1 Highlights: Sequential drying using low humidity air (LHA) and radiofrequency (RF) is explored. Using RF at secondary drying stage with LHA was more efficient than at primary drying. Secondary drying with RF accelerated the drying rate and reduced drying time by 55%. Sequential approach decreased the energy requirement by 52% compared to LHA drying. LHA + RF drying well retained the physicochemical quality & flavour of dried apple.