Flavor Volatiles and Physical Properties of Vacuum-Microwave- and Air-Dried Sweet Basil (Ocimum basilicum L.)

Abstract

Basil (Ocimum basilicum L.) was dried using conventional hot air or the recently developed vacuum-microwave dryers. The effect of the drying method on the relative abundance of major flavor volatiles, rehydration rate, color, and structural integrity of the plant was evaluated. Dynamic headspace analysis of volatiles present in fresh or dried basil revealed that linalool and methylchavicol (estragole) were the two major headspace volatile compounds of the plant sample. Vacuum-microwave dehydrated basil yielded approximately 2.5 times the linalool and 1.5 times the methylchavicol of the air-dried samples. Furthermore, the vacuum-microwave-treated samples yielded more volatiles than fresh basil, due to chemical reactions during drying. Air-dried samples of basil had darker and fewer green hues than those prepared by vacuum microwave. Vacuum-microwave-dried samples had a higher rehydration rate, whereas the potential of the plant material to rehydrate was hindered in air-dried samples. This is likely attributed to the dramatic and pronounced structural collapse of the air-dried cells as revealed by the scanning electron microscope.

Development of Analysis Condition and Detection of Volatile Compounds from Cooked Hanwoo Beef by SPME-GC/MS Analysis

“…However, the use of up to 400 V for volatiles in beef samples was decided because a higher EM also generates basal noise. An EM voltage of 2,000 V and 1800 V for acidic non-steroidal anti-inflammatory drugs (Kim and Yoon, 1996) and for sweet basil (Yousif et al, 1999) were reported, respectively.…”

Drying Technologies: Vehicle to High-Quality Herbs

“…This state-of-the-art setup improves the quality of the end product due to the fast mass transfer caused by vacuum at low temperatures [1,33]. Their hyphenation generates a rapid, low-temperature drying with air absence that may inhibit oxidation of valuable components such as polyphenols [34]. To remove the water content totally using microwave vacuum dryer, large condensers and vacuum pumps are required; therefore, microwave vacuum drying is suggested to be applied in later drying stages [32].…”

Effect of drying method on the antioxidant capacity of six Lamiaceae herbs

“…Drying of herbs inhibits microbial growth and forestalls certain biochemical changes but, at the same time, it can give rise to other alterations that affect herb quality, such as changes in appearance and alterations in aroma caused by losses in volatiles or the formation of new volatiles as a result of oxidation reactions or esterification reactions. Certain compounds (normally present) have been observed to increase in different herbs after drying: for example, eugenol in bay leaf (Diaz-Maroto et al, 2002), thymol in thyme (Venskutonis, 1997), and some sesquiterpenes in different herbs (Baritaux, Richard, Touche, & Derbesy, 1992;Yousif, Scaman, Durance, & Girard, 1999). Most studies have reported changes in colour and volatile compounds of the aromatic herbs after drying (Di Cesare, Forni, Viscardi, & Nani, 2003;Diaz-Maroto et al, 2002).…”