Effect of dehydration techniques on aesthetic and phytochemical parameters of chrysanthemum flower varieties

Introduction

Floriculture, the cultivation and management of flowers and ornamental plants has emerged as a significant sector in India's horticulture industry recognized as a "sunrise industry" due to its robust export potential and profitability. The industry's growth is propelled by increasing domestic and international demand for flowers in various ceremonies and events as well as their applications in perfumes, medicines and decorative purposes. As per a report from the Department of Agriculture & Farmers Welfare, India had approximately 285 thousand hectares under flower crops, yielding around 2.284 million tonnes of loose flowers and 947 thousand tonnes of cut flowers in 2023-2024. Chrysanthemum a popular flower of the Composite (Asteraceae) family holds significant economic and cultural importance worldwide. It is one of the most widely grown ornamental crops globally and ranks among the top ten cut flowers. Chrysanthemums are native to East Asia where they have been cultivated for over 2,500 years. Their popularity stems from their diverse flower forms, colours and long vase life making them ideal for cut flowers, potted plants and landscape ornamentation. Additionally, they are used in traditional medicine and as a source of natural insecticides. The rising global interest in sustainable and eco-friendly products has further boosted the demand for dry flowers which offer a unique appeal due to their extended shelf life, versatility in arrangements and reduced environmental impact compared to fresh flowers. They are used in various applications including home décor, potpourri, crafts and floral art. The process of drying flowers involves removing moisture while preserving their aesthetic qualities such as colour, shape, and texture. Effective dehydration techniques are crucial to ensure that the dried flowers retain their natural beauty and can be used for various value-added products. Proper drying not only preserves the aesthetic appeal but also helps in retaining the phytochemical components which contribute to the medicinal and aromatic properties of the flowers. This study focuses on optimizing these dehydration techniques for Chrysanthemum varieties aiming to enhance their value and extend their usability.

Material and Methods

This investigation was conducted from December 2023 to June 2024 at Anand Agricultural University, Anand, Gujarat. Six chrysanthemum varieties (Dolly White, Pacho, Agina Purple, Ratlam Selection, Sunil and Flirt) were propagated from cuttings in July 2023 and transplanted in August 2023 at a spacing of 45 x 45 cm. Standard cultural practices including fertilization, irrigation, pest and disease management were followed. Fully opened, pest and diseasefree flowers were harvested in January 2024 and subjected to four dehydration techniques:  Sun Drying: Flowers were exposed to direct sunlight (9:00 a.m. to 5:00 p.m.) until moisture content reached 15% with durations varying by variety (10-22 days).  Shade Drying: Flowers were dried in a well-ventilated room away from direct sunlight following similar moisture content goals (12-25 days).  Vacuum Drying: Flowers were dried in a vacuum oven at 65°C and 100 mmHg pressure to achieve 15% moisture.  Embedded Drying with Silica Gel: Flowers were fully embedded in silica gel within airtight containers and kept in a dark and dry room.

Aesthetic parameters (flower colour, shape, brittleness, intactness, texture and overall appearance) were evaluated using ad-hoc scales (Stone et al., 2020) [20] . Phytochemical analyses included total phenols (Bray and Thorpe, 1954) [20] , total flavonoids (Zhishen et al., 1999) [21] , total anthocyanin (Fuleki and Francis, 1968) [23] , total carotenoids (Sadasivam, 1996) [23] , ascorbic acid (Loeffler and Ponting, 1942) [24] , total antioxidant activity (Modified from Benzie and Strain (1996) [25] , total soluble sugars (Dubois et al., 1956) [26] and Chromatographic pigment profile analyses (Singh and Gupta, 2014) [27] and after that statistical analysis was performed for all parameters using Completely Randomized Design-Factorial (Panse and Sukhatme, 1967) [28] .

Result

The effect of different dehydration techniques and varieties with their interaction effect on aesthetic and phytochemical parameters are depicted in Tables 1, 2 and 3.  Optimal preservation of total soluble sugars with significantly highest retention 6.44% was achieved through sun drying of Pacho (D1V2) and least effective retention was found in embedded drying (silica gel) of Dolly White (D4V1) variety which resulted in the significantly lowest total soluble sugars (1.93%).

Effect of drying techniques on aesthetic parameters and phytochemical parameters

Discussion

Findings were consistent with prior studies by Dahiya et al.

(2002) [5] and Bhalla and Sharma (2002) [3] who emphasized the superior preservation capacity of silica gel. Shade drying ranked second in effectiveness attributed to its moderate drying environment that mitigates pigment degradation and structural collapse as also noted by Jangyukala et al. (2022) [7] . Clear varietal differences were also observed supporting earlier findings by Emongor (2007) [6] and Kazaz et al.

(2009) [8] . Interaction effects between dehydration method and variety were also significant supporting the concept of variety-specific dehydration optimization as proposed by Lewicki (1998) [12] and Abbaspour-Gilandeh et al. (2015) [1] . Phytochemical retention was highest under embedded drying as confirmed by Li et al. (2019) [13] , Chandana et al.

(2021) [4] and Lu et al. (2020) [14] . Shade drying also proved beneficial in maintaining ascorbic acid and antioxidant capacity aligning with findings by Ndawula (2007) [15] and Yahia and Cortes-Penela (2003) [18] . Varietal phytochemical variability was also observed which aligned with the findings of Kundu and Panwar (2018) [10] and Patil et al.

(2024) [16] . Chromatographic profiling revealed distinct pigment bands across varieties and treatments validating prior pigment group identifications by Lavanya et al. (2018) [11] , Kim et al. (2008) [9] and Alam (2019) [2] . In conclusion, the study affirms that strategically matching dehydration techniques with chrysanthemum varietal traits is essential for maximizing the aesthetic and phytochemical quality of dried chrysanthemum flowers.

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