Thesis Summary: Standardized Dried Extracts of BrazilianMedicinal Plants: Assessment of Technical and EconomicFeasibility of Spouted Bed Drying

Cl�aaudia Regina Fernandes SouzaUniversity of Sao Paulo, Faculty of Pharmaceutical Science, Ribeirao Preto, Sao Paulo, Brazil

This study is an integral part of a research project which seeksthe establishment of protocols for the production of standardizedherbal dried extracts emphasizing the spouted bed drying. This the-sis was conducted at faculty of Pharmaceutical Science of RibeiraoPreto/University of Sao Paulo, Brazil, under supervision of Prof.Dr. Wanderley Pereira Oliveira�, defended on September 28, 2007.

Keywords Bauhinia forficata; Brazilian medicinal plants; Driedextracts; Drying; Phytopharmaceutical technology;Spouted bed; Techno-economic feasibility

The aim of this work was to investigate the technologicaland economic feasibility of the spouted bed drying processfor production of standardized dried extracts of Brazilianmedicinal plants using the Bauhinia forficata Link as anexperimental model. The objective was to demonstrate thepotential of this technology for the processing of medicinalplants, a world market of 22 billion dollars a year.

Vegetable extracts have complex chemical compositions(fatty acids, sugars, fibers, proteins, and resins), making thedehydration of these materials a challenging task, especiallyfor drying on the surface of inert bodies, like in the case ofspouted bed drying. Thus, the use of drying aids like malto-dextrins, starch, and colloidal silicon dioxide is mandatory.Among the operating problems frequently observed, thereis product accumulation on the surface of inert materials,causing hydrodynamic instabilities and reduction of theequipment productivity. An increase in the thermal degra-dation of the active substances is also observed. This beha-vior is attributed to the increase in the exposure time of thematerial at high temperatures.

The effects of the different proportions of drying aids (20–80%) on the physical properties of the extracts were evaluated

through determination of the surface tension, contact angle,detachment of the extract film from the surface of the inertmaterial, density, and rheological behavior. Drying tests car-ried out with several drying aids showed better performancewith colloidal silicon dioxide, the selected material for furthertests. Drying runs were carried out in two spouted bed config-urations (conventional and with draft tube), according to acentral composite design. The variables studied were the per-centage of the drying adjuvant, the drying gas flow rate, para-meterized by the ratio Q=Qjm, and the flow rate of the extractfed to the system (Ws=Wg).

The statistical analysis results and the effects of inde-pendent variables (% Adj, Q=Qjm, and Ws=Wg) on the pro-duct recovery (Rec), product accumulation in the bed (Ac),loss on drying (Xp), flavonoid degradation (DTF), andmean powder diameter (Dp) showed a significant effect ofthe parameters % Adj and Q=Qjm within the operatingranges investigated. Physical and chemical analyses of thedried product in terms of loss on drying, degradation ofthe active substances, particle size distribution, chromato-graphic profiles, X-ray diffraction, thermal behavior, andthe monitoring of the equipment performance (Recand Ac) were performed. Evaluation of the antioxidantand hypoglycemic activity were carried out for the extractsobtained at optimized conditions, presenting promisingresults. After the technological investigation, an evaluationof the economic viability of the process was carried out.The installation costs of a small-scale unit for productionof dried extracts and the average costs involved for obtain-ing the final product were estimated.

The economic indicators estimated for plants with pro-duction capacity of 100–400 kg=month indicated economicviability. The production plants evaluated presented a posi-tive net present value (NPV). The internal rate of return(IRR) ranged from 17 to 439%. The lowest value of IRRwas presented by a plant with a monthly production of100 kg of dry extract, considering a selling price of theproduct of R$100=kg (�US$55=kg). In this scenario, the

Correspondence: Prof. Dr. Wanderley Pereira Oliveira, Uni-versidade de Sao Paulo, Faculdade de Ciencias Farmaceuticasde Ribeirao Preto, Bloco Q, Av. do Cafe s=n, 14040-903, RibeiraoPreto, Sao Paulo, Brazil; E-mail: wpoliv@fcfrp.usp.br

Drying Technology, 26: 386–387, 2008

Copyright # 2008 Taylor & Francis Group, LLC

ISSN: 0737-3937 print/1532-2300 online

DOI: 10.1080/07373930801898315

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payback time (PBT) was 43 months. Lower PBT wasobtained for a monthly production of 400 kg of driedextract with an estimated selling price of R$200=kg(�US$110=kg). In this scenario the initial capital invest-ment would return in a period of 2.2 months. The netpresent value of the plant operating costs increased withan increase of the production capacity. The maximumnet present value and the minimum payback time wereobtained for the operating capacity of 400 kg=month, witha selling price of dry extract of R$200=kg (�US$110=kg).For a rate of return of 20%, the minimum selling priceestimated for a kilo of dried extract of B. forficata wasR$103.72 for a unit of 100 kg=month and R$72.34 for amonthly production of 400 kg=month.

The results of this work indicated the technical andeconomic feasibility of spouted bed drying for the pro-duction of dried extracts of medicinal plants, emerging asan alternative to spray drying commonly used in thephytotherapeutic processing industries.

ACKNOWLEDGEMENT

Financial support was provided by FAPESP (Fundacaode Amparo a Pesquisa do Estado de Sao Paulo).

PUBLICATIONS BASED ON THIS THESIS

1. Souza, C.R.F.; Donida, M.W.; Rocha, S.C.S.; Oliveira, W.P. The role

of colloidal silicon dioxide on the enhancement of the drying of herbal

preparations in suspended state. Chemical Engineering Communica-

tions 2008 (In press).

2. Oliveira, W.P.; Bott, R.F.; Souza, C.R.F. Manufacture of standardized

dried extracts from medicinal Brazilian plants. Drying Technology

2006, 24 (4), 523–533.

3. Souza, C.R.F.; Bott, R.F.; Donida, M.W.; Rocha, S.C.S.; Oliveira,

W.P. Stickiness on drying of herbal extracts in suspended state:

Requisites of the substrate and feed composition. Proceedings of

the 15th International Drying Symposium; Budapest, Hungary, 20–23

August, 2006; 700–707.

4. Souza, C.R.F.; Bott, R.F.; Oliveira, W.P. Dryer performance and phy-

sico-chemical properties in spray and spouted bed drying of medicinal

plants. Proceedings of the 3rd Inter-American Drying Conference;

Montreal, Canada, 21–23 August, 2005.

5. Souza, C.R.F.; Bott, R.F.; Fernandes, L.P.; Rezende, F.A.; Thomazini,

F.C.F.; Oliveira, W.P. Dehydratation of phytochemical preparations

in a suspended layer of inert material. 6th Congress of Pharma-

ceutical Sciences (6th CIFARP), Ribeirao Preto SP, 2–5 September,

2007; PN018 (CD-ROM).

6. Pepato, M.T.; Souza, A.; Souza, C.R.F.; Vendramini, R.C.; Oliveira,

W.P. Evaluation of Biochemical and Physiological Parameters of

Spouted Bed Dried Extract of Bauhinia forficata (Cows Hoof) on Ani-

mal Model; Libro de Memorias do III Congreso Peruano de plantas

Medicinales: Lima, Peru, 2007.

THESIS SUMMARY: DRIED EXTRACTS OF BRAZILIAN MEDICINAL PLANTS 387