Data of microwave assisted extraction and conventional hot water extraction of Dendrobium Sonia ‘Earsakul’ orchid flower

Crude extracts of fresh Dendrobium Sonia ‘Earsakul’ orchid flowers (DSE) were prepared using microwave assisted extraction (MAE; using household microwave oven) and hot water extraction (HWE; at constant 80 °C). The obtained DSEs were measured their absorbance at λmax of 543 and 583 nm and determined their total monomeric anthocyanin contents (TAC). Mathematical models of MAE of Dendrobium Sonia ‘Earsakul’ orchid flower were constructed using response surface methodology - Box-Behnken design. Studied parameters included flower to water ratio, microwave power, and extraction time, with absorbance at λmax as response. The data generated were 1) visible spectrum (400–700 nm) of DSE; 2) absorbance values at λmax and 3) TAC of DSEs obtained from various extraction conditions of MAE and HWE; 4) linear equations describing correlations between TAC and absorbance at λmax of DSEs; and 5) mathematical models of MAE of Dendrobium Sonia ‘Earsakul’ orchid.


Specifications
Agricultural and Biological Sciences (General) Specific subject area Extraction of crude pigments from flower Type of data Table  Figure How data were acquired Microwave assisted extraction (LG MG-3937C Microwave Oven, LG Electronics, Bangkok, Thailand) Hot water extraction (Memmert Waterbath WNE 22, Schwabach, Germany, set at 80 °C) Spectrophotometry (Shimadzu UV-1280 UV/Vis Spectrophotometer, Bara Scientific Co., Ltd., Thailand) Total monomeric anthocyanin pigment content (pH differential method) Statistical analysis (JMP 8.0 program, SAS Institute Inc., NC, USA) Data format Raw Analyzed Parameters for data collection Parameters for response surface methodology of microwave assisted extraction were flower to water ratio (1:5 to 1:3 g/ml), microwave power (480 to 800 W), and extraction time (2 to 8 min); and response was absorbance at λmax .
Parameter for hot water extraction (at constant 80 °C and flower to water ratio of 1:3 g/ml) was extraction time (10 to 180 min, with increment of 10 min). Efficacies of microwave assisted extraction (MAE) and hot water extraction were assessed through absorbance at λmax (543 and 583 nm)

Description of data collection
Microwave assisted extraction (MAE) and hot water extraction were used to prepare crude extracts from fresh Dendrobium Sonia 'Earsakul' orchid flowers. Response surface methodology (Box-Behnken design) was used to generate extraction conditions for MAE. The extracts were measured their absorbance of visible light (40 0-70 0 nm) and total monomeric anthocyanin pigment content, using pH differential method. The experiment was conducted in triplicate.

Data source location
Purchase of fresh Dendrobium Sonia 'Earsakul' orchid flowers: Taling

Value of the Data
This data set of spectrophotometric properties of crude aqueous extract of Dendrobium Sonia 'Earsakul' orchid flower can be used as reference for optical properties of potential alternative natural dye for both food and non-food applications. The data on mathematical modeling of microwave-assisted extraction of Dendrobium Sonia 'Earsakul' can serve as preliminary data for aqueous extraction of purple Dendrobium orchids prepared for developments of textiles, foods and beverages, or household chemicals. The data of total monomeric anthocyanin content of crude aqueous extract of Dendrobium Sonia 'Earsakul' contributes in building database of anthocyanin-rich plants.   Fig. 1 and Supplemental data 1 report visible spectra (40 0-70 0 nm) of crude color extract from fresh Dendrobium Sonia 'Earsakul' orchid flowers (DSE) obtained through microwave assisted extraction (MAE; flower to water ratio of 1:3 g/ml, microwave power of 800 W, extraction of 8 min) and hot water extraction (HWE; flower to water ratio of 1:3 g/ml, constant 80 °C, extraction time of 120 min). Solvent used was distilled water. Note the difference in dilution factor (DF) of both crude extracts, i.e. 5 and 2 for MAE and HWE, respectively. Table 1 shows linear equations outlining correlations between absorbance at λ max of 543 and 583 nm and the corresponding total monomeric anthocyanin contents (TAC) of DSE. The data included in the analysis belongs to those obtained through MAE method (Supplemental data 2). The predicted total monomeric anthocyanin content of crude extract (cyd-3-glu equivalents, mg/L) can be converted into predicted TAC per weight (cyd-3-glu equivalents, mg/g or mg/kg) of dried orchid flower using data of moisture content wet basis (%) of fresh Dendrobium Sonia 'Earsakul' orchid flower supplied in Supplemental data 3.

Materials and reagents
Fresh Dendrobium Sonia 'Earsakul' orchid flowers (growth stage 5) [1] were purchased from local supermarkets in Bangkok, Thailand. Fresh orchids were stored at 4 ± 1 °C until used and used within 3 days of purchase. Flowers were cut into small pieces and only the parts with purple color, i.e. majority of petal part, were used ( Fig. 4 ). The cut petals were subjected to extraction process within 1 h of size reduction. Whatman R filter paper No. 1 (Sigma-Aldrich, Inc., St. Louis, MO, USA) was purchased from Business organization of the office of the welfare promotion commission for teachers and educational personnel (BOWT), Bangkok, Thailand. Disposable plastic cuvette (Bibby Scientific Ltd., Staffordshire, UK) was used in UV-Vis spectrophotometry.
For determination of total monomeric anthocyanin pigment content, colorless buffer solutions of pH 1.0 and 4.5 used were prepared from potassium chloride (0.025 M) (KCl, Ajax Finechem, New South Wales, Australia) and sodium acetate (0.4 M) (CH3CO2Na ·3H2O, Ajax Finechem), respectively. The buffer solutions were adjusted their final pH with hydrochloric acid (HCl, Fisher Scientific, MA, USA) [2] . + + 0 1:3 800 5 * Extraction condition of flower to water ratio of 1:3 g/ml, microwave power of 800 W, and extraction time of 8 min ( + + + ) was not included as treatment according to RSM-Box-Behnken design; the extraction was done additionally and the data was list in Fig. 2 and Supplemental data 2 along with those obtained using extraction conditions list in the table.

Microwave assisted extraction
Prior to extraction, known amount of cut flower pieces were immersed in distilled water at room temperature, for 60 s to ensure thorough submersion. Table 3 shows microwave assisted extraction (MAE) conditions for cut orchid flowers. The extractions were performed in random order according to Box-Behnken design with response surface methodology. All extractions were conducted in triplicate. Household microwave oven (LG MG-3937C Microwave Oven, LG Electronics, Bangkok, Thailand) was used for microwave heating process. After the extractions, the heated mixtures were filtered, and DSEs were collected and left to cool to room temperature [3] .

Hot water extraction
Freshly cut orchid flowers were submerged in 80 °C distilled water (flower to water ratio of 1:3 g/ml) placed in temperature-controlled water bath (Memmert Waterbath WNE 22, Schwabach, Germany), for 10 to 180 min (in increment of 10 min). The heated mixtures were filtered through Whatman filter paper No. 1. The filtrates were collected and used as DSEs, and the plant residues were discarded. DSEs were left to cool to room temperature before further testing. All experiments were performed in triplicate.

Determination of total monomeric anthocyanin pigment content
Total monomeric anthocyanin pigment content in DSEs was determined according to pH differential method [2] . The extracts were mixed with pH 1.0 or pH 4.5 buffer solutions for final concentration of 10% vol/vol, and then the mixtures were measured their absorbance at 520 and 700 nm, using UV-Vis spectrophotometer. The anthocyanin pigment content, as cyanidin-3glucoside, was calculated as described in Eq. (1) and 2 .

Statistical analysis
All data obtained were statistically analysed using JMP 8.0 program (SAS Institute Inc., NC, USA) at the confidence level of 95% ( α = 0.05) with Tukey's adjustment for comparison of the means.

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.