• International Journal of Technology (IJTech)
  • Vol 15, No 4 (2024)

Effect of Drying Pretreatment Methods on Amla (Emblica officinalis) Extracts Obtained Through Maceration Using Ethanol as Solvent

Effect of Drying Pretreatment Methods on Amla (Emblica officinalis) Extracts Obtained Through Maceration Using Ethanol as Solvent

Title: Effect of Drying Pretreatment Methods on Amla (Emblica officinalis) Extracts Obtained Through Maceration Using Ethanol as Solvent
Auliyaa Raaf, Farid Mulana, Yanna Syamsuddin, Nanda Suriaini, Muhammad Dani Supardan

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Cite this article as:
Raaf, A., Mulana, F., Syamsuddin, Y., Suriaini, N., Supardan, M.D., 2024. Effect of Drying Pretreatment Methods on Amla (Emblica officinalis) Extracts Obtained Through Maceration Using Ethanol as Solvent. International Journal of Technology. Volume 15(4), pp. 917-926

Auliyaa Raaf Doctoral Program, School of Engineering, Post Graduate Program, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
Farid Mulana Department of Chemical Engineering, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
Yanna Syamsuddin 1 Department of Chemical Engineering, Universitas Syiah Kuala, Darussalam, Banda Aceh, 23111, Indonesia 2 Halal Research Center, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia
Nanda Suriaini Department of Chemical Engineering, Universitas Syiah Kuala, Banda Aceh, Indonesia 23111
Muhammad Dani Supardan 1 Department of Chemical Engineering, Universitas Syiah Kuala, Darussalam, Banda Aceh, 23111, Indonesia 2 Halal Research Center, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia
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Effect of Drying Pretreatment Methods on Amla (Emblica officinalis) Extracts Obtained Through Maceration Using Ethanol as Solvent

This study investigated the effects of drying methods on the yield, bioactive compounds, and antibacterial activity of amla extract. Fresh amla was oven-dried and sun-dried at different temperatures and ground into powder. Bioactive compounds were extracted from amla using maceration with ethanol as a solvent. The amla extract was used for the antibacterial susceptibility test using the agar disc diffusion method. The yield of amla extract increased with increasing drying temperature. The highest yield (53.47%) was obtained at a drying temperature of 70o C. Fourier Transform Infrared (FTIR) analysis confirmed that sun-drying and oven-drying exhibited no qualitative effect on the bioactive compound in amla extract. FTIR analysis also indicated that amla extract contains bioactive compounds, validated by phytochemical analysis. The antibacterial activity of oven-dried samples at 40 oC produced the largest inhibition zone (24.57 mm) compared to sun-drying and oven-drying at other temperatures. It can be concluded that drying temperature, especially higher temperatures, had a significant impact on the antibacterial activity of amla as its active components degraded.

Amla extract; Antibacterial activity; Bioactive compound; Drying methods


Amla (Emblica officinalis) has long been recognized for its health benefits and has been used as a medicinal plant and in food preparation. It is currently distributed in India, Sri Lanka, South-East Asia, China, and Indonesia (Khan, Qais, and Ahmad, 2019) and is available in large quantities for food and pharmaceutical purposes. Amla has been extensively used as a medicinal plant to treat inflammation, as an antibacterial, and to treat cancer (Pareek and Kitinoja, 2011). A previous study has reported that amla has high pharmaceutical activity, sparking interest due to its potential as an antibacterial source (Jahan and Akter, 2015).

The potential of amla as a medicinal plant is mostly due to the bioactive compounds contained in the plant, which can treat various diseases in the human body. The bioactive compounds include flavonoids, tannins, alkaloids, saponins, and phenolic compounds (Arina and Harisun, 2019). Hussein, Mamman, and Mansur (2015) reported that the therapeutic effects of these medicinal plants are usually marked by the presence of secondary metabolites, which differ from one plant to another. Phytochemicals are secondary metabolites naturally present in plants (Guluma et al., 2020). These phytochemical compounds act as natural antioxidants and can inhibit the formation of free radicals and lipid peroxidation (Ajak et al., 2020). Phytochemical compounds such as flavonoids also have antimicrobial properties (Abdullah et al., 2019). Bin Fazal and Ahmad (2024) recently reported on the potential use of amla extract as a capping and reducing agent in the synthesis of zinc-oxide nanoparticles, suggesting it as an alternative to surfactants.

Bioactive compounds, mainly phytochemical content from amla, are extremely important for many purposes. The phytochemical content of amla extract is heavily influenced by how the extract is produced. Maceration is an extraction method commonly used to extract bioactive compounds from plant materials through the use of solvents (solid–liquid extraction) (Safdar et al., 2017). Ethanol is one of the most widely used solvents for the extraction of plant bioactive compounds, such as alkaloids and flavonoids (Pratiwi, Utami, and Arbianti, 2020). Ethanol is also considered a food-grade solvent (Dianursanti et al., 2020).

The extraction of bioactive compounds from a plant begins with the drying of the plant. Plant drying aims to produce raw materials in simplicia, facilitating the extraction of phytochemicals with a high yield, and facilitating plant storage for future use (Amir et al., 2021; Hasmita et al., 2015). Additionally, drying significantly reduces volume, thereby saving on packaging, storage, and transportation costs (Sonkar et al., 2020). Gudapaty et al. (2010) reported that drying affects the quality attributes of amla. The drying pretreatment method can affect the input energy, increase the extraction yield, and increase the quality of the extracted bioactive compounds. Thus, drying methods must be evaluated to determine their effect on extracted bioactive compounds.

For continuous production of amla extract, drying techniques must be determined for recommendation to producers. Raaf et al. (2022) reported the impact of temperature and drying methods on amla's drying kinetics and microstructure. However, little information has been reported regarding the effect of the drying method on bioactive compounds. Thus, this research evaluates the effects of oven-drying (at different temperatures) and sun-drying on the phytochemical content and antibacterial activity of amla.

Experimental Methods

2.1. Materials

      The study used amla collected near Blang Bintang, Aceh Besar. The solvent used for the extraction process was ethanol 96% (Merck, Germany). The antibacterial assay used nutrient agar (Oxoid, UK) and amoxicillin (Mersi, Indonesia). The bacterial species used were Staphylococcus aureus ATCC 25923, obtained from stock cultures of Fundament Lab Sains, Aceh Besar.

2.2. Drying Methods

       Fresh amla was washed with clean water and thinly sliced and dried. Cutting was performed to ensure that the amla samples dried evenly. The amla was sun-dried (SD) in air temperatures of 37–45 OC. For oven-drying (OD), amla was placed on a tray and dried at four different temperatures (40  OC, 50 OC, 60OC, and 70 OC). All samples were ground into a fine powder using an electric blender and screened through a mesh sieve to obtain a uniform size.

2.3. Extraction Procedure

       The extraction method used in this study was maceration at room temperature. An illustration of the amla maceration process is presented in Figure 1. Dried amla (30 g) from each drying method was soaked in 150 mL ethanol 96% for 72 h. Maceration at room temperature (28 OC) was conducted in an Erlenmeyer flask covered with aluminum foil. The resulting mixture was filtered with Whatman no. 1 filter paper and concentrated using a rotary evaporator in a vacuum at 40 OC. The yield of each extract was determined by Equation (1).

2.4. Analysis Method

       Proximate analysis of amla powder was conducted to analyze parameters such as fat content, carbohydrates, protein, moisture, and ash using the standard method as per Indonesian National Standard (SNI) 01-2891-1992 procedures.

       The preliminary phytochemical evaluation of each extract was qualitatively tested to determine the presence of flavonoids, alkaloids, tannins, saponin, quinone, steroids, and triterpenoids. The tests were performed according to the methods reported by Guluma et al. (2020).

       A Fourier transform infrared spectrophotometer (FTIR Shimadzu Prestige 6400) was used to identify the functional group of amla extract. The spectra were observed in the wavenumber region of 4000–400 cm-1. A Carl Zeiss-Bruker EVO MA10 scanning electron microscope (SEM) was used to observe the morphological changes of the dried amla powder after extraction. The analysis was presented using a 1000× magnification.


Figure 1 Illustration of the amla extraction process using maceration

2.5. Antibacterial Assay

       The antibacterial activity of the amla extract was tested using the Kirby–Bauer agar disk diffusion method, as reported by Zullkiflee et al. (2022). S. aureus (ATCC 25923) was used in this study. The nutrient agar (NA) was used as the media. The NA was compacted in a Petri dish, and the bacterial culture was inoculated and diluted with 0.5 McFarland standard. The amla extract-soaked paper disk was drained and impregnated on the agar plate medium surface. The plates were incubated for 24 h at 37  OC. The clear zone around the paper disk was measured to determine the antibacterial activity. All results were compared to distilled water as a negative control and the standard antibiotic (amoxicillin) as a positive control.

Results and Discussion

3.1. Proximate Analysis of Dried Amla Powder

The proximate composition of dried amla powder is presented in Table 1. The proximate analysis results indicate that the carbohydrate and ash values are similar to those reported by Mishra and Mahanta (2014) for amla fruit powder; the fat and protein content was lower. This is a result of fruit from different geographical locations, which affects the nutritional content of the fruit, including fat and protein, as reported by Okeke et al. (2021). The fat content of amla ranged from 0.36% to 0.48% (Parveen and Khatkar, 2015). The protein content in amla is used by the body for growth and maintenance. Protein also plays a role in the formation of blood cells and antibodies that protect the body from disease and infection (Hermann, 2019). The obtained moisture content was high (10.08%). A less than 10% moisture content must be maintained to prevent microbial growth in dry food products (Zambrano et al., 2019). Thus, proper pretreatment is required to limit the amount of moisture in dried amla powder without reducing its nutritional value.

Table 1 Proximate analysis of dried amla powder


Content (%)











3.2. Effect of Drying Methods on Amla Extract Yield

The effect of the drying method on the yield of amla extract is presented in Figure 2. Oven-drying at 50-70oproduced a higher amla extract yield than sun-drying. The amla extract yield was slightly higher with sun-drying than with oven-drying at 40oC as the drying temperature was 40–45 oC. This indicates that drying methods have a linear effect on the increase in amla extract yield. These results are consistent with those reported by Justine et al. (2019).

The amla extract yield increased linearly with increasing drying temperature, related to the moisture content in the amla. Higher drying temperatures produced a lower moisture content in the amla (Raaf et al., 2022). Thermal drying causes cell wall damage, facilitating the release of phytochemical compounds and increasing amla extract yield (Justine et al., 2019). Cell wall damage caused by thermal drying is shown in Figure 3. Higher drying temperatures can increase cell wall damage (Figure 3B). Raaf et al. (2021) reported that the amount of water in the material at high temperatures was smaller, resulting in the stretching of the plant cell wall structure, which facilitated the rupture of the cell wall into small particles.

Figure 2 Effects of sun-drying (SD) and oven-drying (OD) on amla extract yield

Figure 3 Effect of drying temperature on the cell wall damage after extraction: A: 50 oC; B: 70 oC

        The effect of the extraction process on cell wall damage is presented in Figure 4. Figure 4A shows the cell wall damage caused by thermal drying pretreatment. Figure 4B shows the cell wall damage caused by ethanol penetration during the extraction process. The pretreatment drying damaged the amla cell wall, facilitating ethanol to more easily extract phytochemical compounds from amla cells (Dianursanti et al., 2020). This is also characterized by greater cell wall damage after extraction.

Figure 4 Effect of extraction on cell wall damage: A: before extraction (after oven-drying at 60 oC); B: after extraction

The effect of the drying method on cell wall damage after extraction is presented in Figure 5. Sun-drying (Figure 5A) and oven-drying at 40 oC (Figure 5B) have similar thermal temperatures, with a difference of 5 oC. Cell wall damage caused by thermal drying is difficult to determine. The amla extract yield was 1% greater with sun-drying than with oven-drying at 40 oC (Figure 2). Cell wall damage after extraction appeared to be greater with oven-drying at 40 oC than sun-drying. Oven-drying has a closed drying system; sun-drying has an open drying system. There is less heat loss in oven-drying than sun-drying (Babu et al. 2018). Thus, oven-drying at 40 oC (Figure 5B) observed greater cell wall damage than sun-drying (Figure 5A).

3.3. Effect of Drying Method on Phytochemical Analysis of Amla Extract

        Amla extract has a high polyphenols content (Kumari and Khatkar, 2016). Polyphenols are natural phytochemical compounds in plants. Chemically, polyphenols have one or more phenol groups. The phenol group comprises one or more hydroxyl groups (-OH) bonded to an aromatic ring (Aneklaphakij et al., 2021). Polyphenols are also known as phenolic compounds. Polyphenols can inhibit bacterial growth (Aneklaphakij et al., 2021) because they contain flavonoids, saponins, and tannins as bioactive compounds (Arina and Harisun, 2019). Thus, amla extract is promising as an antibacterial agent (Variya, Bakrania, and Patel, 2016). The bioactive compounds in amla extract must be identified. This study used FTIR analysis to identify the bioactive compounds in amla extract based on their functional groups. The FTIR spectrum of amla extract is presented in Figure 6.

Figure 5 Effect of drying method on cell wall damage after extraction: A: sun-drying; B: oven-drying at 40 oC

Figure 6 FTIR spectrum of amla extract (sun-drying (SD) and oven drying (OD) at 4070oC)

The FTIR spectra of amla extract exhibited several main peaks. The peak at 3652–3588 cm-1 indicates the presence of –OH (stretching) vibration of the phenol group (Nandiyanto, Oktiani, and Ragadhita, 2019). The C-H vibration was found at 2964–2957 cm-1. It exhibits phenolic aromatic compounds (Öztürk et al., 2019). The peak at 1759–1754 cm-1 shows the ester group's C=O (stretching) vibration (Nandiyanto, Oktiani, and Ragadhita, 2019). Peaks at 1473–1470 cm-1, 1410–1409 cm-1, and 1257–1254 cm-1 indicate C=C-C (stretching) vibration of the aromatic ring, -OH (bending) of the phenol group, and C-O (stretching) of the phenol aromatic ring, respectively (Nandiyanto, Oktiani, and Ragadhita, 2019). Overall, the FTIR spectra exhibited good consistency with the results reported by Firdous, Ringø, and Elumalai (2020). Polyphenol compounds are indicated by the functional groups of –OH, C=O, and C-O (Raaf et al., 2021). This ester group indicates the presence of flavonoids (Noh, Azmin, and Amid, 2017), saponins (Almutairi and Ali, 2015), and tannins (Grasel, Ferrão, and Wolf, 2016).

The results are also supported and confirmed by identification using the reagents presented in Table 2. Flavonoids, saponins, and tannins were qualitatively identified through FTIR and phytochemically by reagents in amla extract under each drying condition. The results indicated that sun-drying and oven-drying had no qualitative effect on the phytochemical compounds in amla extract.

Table 2 Phytochemical analysis of amla extract

3.4. Antibacterial Activity

        In this study, amla extract was used as an antibacterial agent. The bioactive compounds in amla extract can form complexes with bacterial cell walls, which disrupt bacterial cell membranes. Kumari and Khatkar (2016) also observed the antimicrobial activity of amla extract on several bacterial species, including Staphylococcus aureus (S. aureus). The antibacterial activity of amla extract on S. aureus with different drying methods is shown in Figure 7 and Table 3.