Coriandrum sativum L.-Effect of Multiple Drying Techniques on Volatile and Sensory Profile

Abstract

Coriandrum sativum L. is a medicinal and aromatic plant spread around the world, with beneficial properties that are well recognized. Both coriander seeds and leaves are used for pharmaceutical and flavoring purposes. Even though coriander seeds tend to be more popular, the leaves are receiving a consistently growing interest, especially because of popularization of Mexican, Northern African, and Indian cuisines. This increased attention brings about the necessity for providing the product with guaranteed quality, which will retain its valuable characteristics, even after post-harvest treatment. For this reason, it is highly necessary to determine reliable protocols for cilantro preservation, which usually include drying procedures; in order to identify the optimal drying treatments, a spectrum of drying techniques-convective, vacuum-microwave, and a combination of convective and vacuum-microwave-were evaluated. Cilantro-based dried products were examined from the perspectives of volatile organic constituent composition and sensory quality. After headspace solid-phase microextraction-GC/MS analysis and sensory tests, the results demonstrate that convective drying at 70 °C for 120 min followed by vacuum-microwave drying at 360 W and convective drying at 70 °C were the optimal drying methods for preserving cilantro aroma quality, while convective drying at 70 °C for 120 min followed by convective finishing drying at 50 °C decreased cilantro aroma quality.

Keywords: HS-SPME-GC/MS; OACs; VOCs; chemistry behind quality; coriander; napping.

Figure 1

Drying kinetics of cilantro obtained by (a) convective drying at 50, 60 and 70 °C; (b) convective pre-drying for 120 min at 50, 60 and 70 °C followed by convective finishing drying; (c) vacuum-microwave drying at 240, 360 and 480 W; (d) combined convective pre-drying at 50, 60 and 70 °C followed by vacuum-microwave finishing drying at 360 W—results presented for VMFD part of the treatment.

Figure 2

Napping test results for cilantro treated with various drying methods presented as biplot generated with MFA, which explains 44.25% of the variance. Samples were grouped in the napping test according to the groups established in a clustering dendrogram prepared using Pearson’s correlation based on the unweighted average.

Figure 3

Descriptive sensory results for cilantro samples from each type of drying treatment. The scale used ranged from 0 = no intensity to 10 = extremely strong intensity; *, **, and *** significant at p < 0.05, 0.01, and 0.001, respectively.