Low humidity air and radiofrequency wave based sequential drying of Rosmarinus officinalis for improvement of quality.

Sandhya, R. Shewale and Umesh Hebbar, H. (2021) Low humidity air and radiofrequency wave based sequential drying of Rosmarinus officinalis for improvement of quality. Industrial Crops & Products, 162. p. 113303.

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Abstract

Rosemary (Rosmarinus officinalis L) is an aromatic herb and used worldwide for its medicinal as well as for flavoring properties. The present investigation explores the sequential combination of low humidity air (LHA) and radiofrequency (RF) waves for drying of rosemary for improvement of product quality. The two sequential drying approaches were studied, namely, RF followed by LHA (RF + LHA), and LHA followed by RF (LHA + RF) in comparison with hot air (HA), LHA at 40 ◦C, and RF (1.8 A, 40 ◦C) drying alone. Quality of dried rosemary was estimated in terms of retention of volatiles and phytochemicals and compared with freeze-dried (FD) product. The LHA + RF sequential approach significantly reduced the drying time by 60 % and 40 % as well as energy consumption by 27 and 40 % compared with HA and LHA drying, respectively. RF drying required the shortest drying time (120 min) but produced an inferior quality product. The LHA + RF dried rosemary had bright green color and retained higher content of essential oil (86 %), ascorbic acid (81 %), polyphenols (88 %), carnosic (81 %) and rosmarinic acid (76 %) compared with RF + LHA. Oxygenated monterpenes represented 60 % of volatile compounds and α-pinene, eucalyptol, camphor, D-verbenone were majorly contributing to rosemary flavor. A principal component analysis demonstrated that rosemary dried by LHA + RF had higher volatiles and quality close to FD. Overall, results provide a basis for potential application of sequential drying using LHA + RF for energy-efficient and accelerated drying of other heat-sensitive herbs with better preservation of phytochemicals and volatile compounds.

Item Type:	Article
Uncontrolled Keywords:	Drying kinetics Energy Essential oil Volatile compounds Principal component analysis
Subjects:	600 Technology > 03 Agriculture > 04 Medicinal Plants 600 Technology > 08 Food technology > 06 Preservation and Storage > 02 Drying and Dehydration
Divisions:	Food Engineering
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	18 May 2021 05:44
Last Modified:	18 May 2021 05:44
URI:	http://ir.cftri.res.in/id/eprint/14860

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