Dataset of volatile compounds from flowers and secondary metabolites from the skin pulp, green beans, and peaberry green beans of robusta coffee

We obtained data regarding the metabolites from flowers, the skin pulp, green beans and peaberry green beans of the robusta coffee plant (Coffea canephora). The beans were processed using a wet-hulled method. The volatile compounds from the flowers were extracted using a solid-phase microextraction. Secondary metabolites from the skin pulp, green beans, and peaberry green beans were extracted by a maceration method using methanol as a solvent. The separation and identification of metabolites were conducted using gas chromatography-mass spectrometry. The flower's volatile compounds were identified by matching the generated spectra with the NIST14 library as a reference, whereas the metabolites in the skin pulp, green beans, and peaberry green beans were identified using the WILLEY09TH library as a reference. The identified volatile compounds in flowers have been listed in Table 1, and the identified skin pulp, green bean, and peaberry green bean metabolite compounds have been listed in Table 2.


Data description
These raw data include information on the volatile compounds of the robusta coffee flowers and the profiles on the secondary metabolites of the skin pulp, green beans, and peaberry green beans of the robusta coffee. The raw data have been provided in a Microsoft Excel Worksheet (Tables 1 and 2) and have been presented with retention times, identified volatile compounds, and peak areas.

Experimental design, materials, and methods
a. Preparation and analysis of the flower samples All samples were collected from a low land robusta coffee orchard (at 680 m above sea level). Only fresh anthesis flowers were picked for analysis. Three sets of samples (10 fresh anthesis of the robusta coffee flowers, approximately 1.5 g) were placed in 22-mL clear glass bottles for SPME with PTFE/ Silicon septa (Supelco Co., Bellefonte, PA, USA). After 24 h, the flowers were extracted and identified by Specifications Table   Subject Agriculture and Biological Science Specific subject area Biochemical diversity. The data provide insights into the metabolic profiles of flowers and green beans from the robusta coffee plant, demonstrating a biochemical diversity Type of data Table  How data were acquired The volatile compounds from the flowers of the robusta coffee plant were extracted by solid-phase microextraction (SPME) and analyzed using gas chromatography-mass spectrometry (GC-MS; GC: 7890A, MS: 5975C, Agilent Technologies, Inc., CA, USA). The skin pulp, green beans, and peaberry green beans were extracted using a maceration method with a methanol-based solvent and were analyzed using GC-MS (GC: 6890N, MS: 5973, Agilent Technologies, Inc.) Data format Raw Parameters for data collection The five parts of the robusta coffee plant, i.e., flowers, skin pulp of beans, skin pulp of peaberries, green beans, and peaberry green beans, were analyzed. All parts were collected from Coffea canephora cv. Tugusari. Description of data collection All samples was collected from a low land robusta coffee orchard (at 680 m above sea level). Only fresh anthesis flowers and mature coffee fruits (cherries) were picked for analysis. The beans were processed using a wet-hulled method. Volatile compounds in the coffee flowers were analyzed, and the profiles of secondary metabolites were analyzed from the skin pulp and beans. Floral volatile compounds were extracted by SPME, whereas metabolites from the skin pulp and beans were extracted by maceration with methanol as a solvent. Identification of volatile compounds, determination of retention times, and measurement of peak areas were performed using GC-MS. Data source location Jember District, East Java e Indonesia at South Latitude 08 13 0 and East Longitude 113 55'.

Data accessibility
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Value of the Data
These data contributed to our understanding of volatile compounds in the flowers and secondary metabolites in the skin pulp and beans from the robusta coffee plant, respectively. The data are important for coffee entrepreneurs or coffee merchants (torrefacteurs), researchers, academics, farmers, and policymakers involved in coffee plantation management. Elucidation of the volatile compounds of the robusta coffee flowers is important for improving our understanding of the chemical/metabolic diversity and recognition of potential insects as pollinators that may contribute to the pollination of the robusta flowers. Information on the secondary metabolites of the skin pulp may facilitate the development of insect attractants or repellents, which may contribute to pest control programs. The data on the metabolites of robusta beans may be used to understand the effects of different postharvest treatments (such as wet-hulling) on the quality and flavors of the robusta coffee. The data on metabolites from the skin pulp may also be important for other uses of the beans, such as in teas or infusions. an SPME connected with a GC-MS (GC: 7890A, MS: 5975C, Agilent) following the procedure reported by Syamsudin et al. [1]. Coffee flowers in the SPME bottles were extracted at 40 C for 45 min. The extract was injected into a gas chromatograph at 250 C for 5 min using a spitless mode. The oven temperature was initially set to 50 C and held for 5 min. Then, the temperature was increased to 150 C (5 C/min for 2 min) and then to 250 C (5 C/min for 5 min). An HP-5MS (30 m Â 250 mm Â 0.25 mm) column was used to separate the volatile compounds with helium as the carrier gas injected at 0.8 mL/ min. The flower volatile compounds were identified by matching the generated spectra with the spectra in the NIST14 library as references.

Preparation and analysis of skin pulp and bean samples
Only red fruits of the coffee plants were included in this analysis. All fruits ('normal' beans and peaberries) were picked by hand from the orchard and processed using the wet-hulled method. Washed coffee fruits were then peeled to obtain the skin pulp. The seeds (beans) were fermented anaerobically for 12 h in a sealed plastic bag, and the mucilage was then washed away. The skin pulp and beans were dried in a screen house (temperature: 32.90 C ± 5.87 C; relative humidity: 46.14% ± 16.26%) for 3 weeks. According to standard agricultural practices, the skin pulp and beans were kept at room temperature (24e26 C). Then, the skin pulp and beans were freeze dried for 24 h and crushed using a coffee grinder (Cyprus International 200W). Next, 100 mg powder of each sample (skin pulp beans, skin pulp peaberry beans, green beans, and peaberry green beans) was macerated for 4 Â 24 h using methanol. All extracted samples were evaluated in duplicate. The extract was filtered (Whatman paper No. 91) then evaporated with a rotary evaporator. The macerated samples were redissolved in 1 mL methanol (chromatography-grade; Merck LiChrosolv Reag. Ph Eur). Before injecting into the GC-MS, the sample was filtered with a 0.22-mm/25 mm PTFE filter syringe (Axiva Sichem Biotech Pvt. Ltd. India).
Extraction of the skin pulp and beans was performed with the Sunarharum method [2] using GC-MS with some modifications. The extract was injected into the GC-MS (GC: 6890N, MS: 5973; Agilent Technologies Inc.) at 290 C using a split mode. The initial oven temperature for green bean and peaberry green bean extracts was set to 50 C. The temperature was increased to 220 C (10 C/min) and then to 290 C (5 C/min for 10 min). For 'normal' bean skin pulp and peaberry skin pulp extracts, the temperature was increased to 290 C at 10 C/min for 15 min. An HP-5MS (30 m Â 250 mm Â 0.25 mm) column was used to separate volatile compounds with helium as the carrier gas at 1.0 mL/min. The compounds were identified by matching the generated spectra with the spectra from the WILLEY09TH library database.