Probir Kumar Ghosh

Mathematical modeling of supercritical carbon dioxide extraction of methyl eugenol from tuberose flowers

Methyl eugenol-rich extracts from dried tuberose flowers (Polianthes tuberosa L.) of Calcutta single variety were obtained using supercritical carbon dioxide (SC-CO2) extraction. The optimized conditions for highest yield of methyl eugenol were 50 °C, 300 bar, 135 min with 1 L min−1 flow rate of gaseous CO2. Solubilities of methyl eugenol under different SC-CO2 extraction conditions were evaluated by Hildebrand solubility parameter and Chrastil equation. The extraction curve of methyl eugenol followed plug flow model. Steady state extraction occurred up to 100min, followed by unsteady state. Release of methyl eugenol from tuberose flowers followed first-order kinetics (Peppas model) and non-Fickian diffusion. Packed bed characterization was carried out using dimensionless numbers of mass transfer, considering steady and unsteady states of extraction. These findings could be used in the development of the pilot plant and commercial scale extraction of methyl eugenol from floral matrices.

Effect of Packaging on Shelf-life and Lutein Content of Marigold (Tagetes erecta L.) Flowers

BACKGROUND African marigold (Tagetes erecta L.) flowers are highly valued for their ornamental appeal as well as medicinal properties. However, their short shelf lives cause high post-harvest loss and limit their export potential. The review of patents and research articles revealed that different types of packaging designs/materials have been successfully employed for extension of shelf lives of cut flowers. OBJECTIVE The current work focuses on designing of different packaging configurations and selection of best configuration for preservation of marigold cut flowers. METHODS Ten packaging configurations, composed of four different packaging materials i.e., low density polyethylene (LDPE), polyethylene terephthalate, glassine paper and cellophane paper, were designed. Each pack, consisting of 20 ± 1 g of marigold flowers along with non-packaged control set were stored at 23 ± 2°C, 80% R.H., in an environmental chamber and the flowers were evaluated for their sensory attributes, phytochemical characteristics and physicochemical parameters of senescence to determine their shelf lives. RESULTS Flowers packed in LDPE bag showed highest shelf life of 8 days with a lead of 4 days compared to control (shelf life - 4 days). This study also established for the first time the phenomenon of carotenogenesis in marigold cut flowers with significantly (P<0.01) higher production of lutein in LDPE packaged flowers. CONCLUSION LDPE pack was the best design among the ten package designs, in preserving lutein content of marigold flowers and extending their shelf lives. This economically viable packaging can not only boost the export potential of this ornamental flower, but also allow utilization of nutraceutical potency of lutein.

Physicochemical and Phytochemical Analyses of Copra and Oil of Cocos nucifera L. (West Coast Tall Variety)

Coconut copra from West coast tall variety, cultivated in Kerala, India, was subjected to aqueous and solvent extractions (using n-hexane). Additionally, oil was extracted from the copra in Soxhlet assembly using petroleum ether (b.p. 60–80°C). Physicochemical and phytochemical analyses were conducted for the extracts and the oil, with commercial coconut oil as the experimental control. The physicochemical analyses showed that the aqueous extract of copra was milky-white in color with a sweet odor, while the solvent extract was pale yellow and odorless. The commercial oil had 0.08 ± 0.02% oleic acid and a TOTOX value of 7.73 ± 0.78, lower than the Soxhlet extracted oil. Among all the extracts and oils, best phytochemical properties, antioxidant activity (DPPH activity, IC50 value 0.04 ± 0.01 mg/mL), total phenol (0.96 ± 0.04 mg gallic acid eq./g dry copra), reducing power (40.49 ± 1.84 mg BHT eq./g dry copra), and anti-inflammatory activity (NO activity, IC50  value 0.77 ± 0.06 mg/mL) were obtained in the commercial coconut oil, followed by the Soxhlet extracted oil, aqueous extract, and solvent extract. Fatty acid composition analyses showed mainly medium chain fatty acids in the copra oil with lauric acid as the predominant fatty acid (51.88% and 44.84% in Soxhlet extracted and commercial oils, resp.).

Extension of shelf life of tuberose flowers using a combination of gamma irradiation and generally regarded as safe (GRAS) preservatives and assessment of antimicrobial potency of senesced flowers

ABSTRACT Tuberose cut flowers, available as loose flowers, were treated with gamma (γ) irradiation and generally regarded as safe (GRAS) preservative solutions for extension of shelf life. The flowers were packaged in low-density polyethylene bags, heat sealed and stored at 23 ± 2°C, 80% relative humidity (RH) and 4 ± 1°C, 40% RH, respectively. The flowers stored at these two temperature regimes were subjected to sensory evaluation and biochemical analyses. From these assessments, the longest shelf life of tuberose flowers was found to be 8 days at 23 ± 2°C, 80% RH (compared to 4 days for control) and 24 days at 4 ± 1°C, 40% RH (compared to 8 days for control) using combination treatment of low dose γ-irradiation (0.02 kGy) and preservative solutions (4% sucrose and 0.02% CaCl2). Ethanolic extract of tuberose flowers of the most shelf stable set (stored at 4 ± 1°C), i.e. at the end of 24 days, showed antimicrobial potency against the common skin pathogen Staphylococcus aureus (ATCC 25923 and MDR strains), suggesting utility of the senesced tuberose flowers for therapeutic applications. This preservation technique would promote export of tuberose flowers by extension of their shelf lives and allow utilization of these flowers, post senescence.