Proximate, total phenolic, carotenoid, antioxidant activity, color, and FTIR analysis of red ginger powders (Zingiber officinale var. Rubrum) through the evaporation-crystallization process

Red ginger is a plant that is rich in antioxidants and is easily available in Indonesia. So far, red ginger has been used with various extraction methods by previous researchers, but the application of this process has not been able to be used by independent economic MSMEs. This research took place using evaporation-crystallization equipment as the main tool, accompanied by temperature variations (80 and 90°C) and granulated sugar as a crystallization agent (60 and 100%). The quality of the powdered red ginger product analyzed in this study showed good stability values for the fresh red ginger raw material before processing. The average value of the proximate content of red ginger products is 7.668; 12.116; 5.225; 0.422-1.708; 73.960% for moisture, ash, fat, protein, and carbohydrate content, respectively; and total glucose of 63.768 ppm. Meanwhile, the results of the phenolic and carotenoid content provide a significant reduction of up to 50%. The average content is 42.459 mg gallic acid/g; and 5.480 g respectively (including color - also a decrease in L, a, and b values) compared to the red ginger pulp raw material. The opposite value occurred in the DPPH antioxidant activity of red ginger pulp, the content of which was 2-3 times higher than fresh red ginger. These findings not only have an impact on the development of more health-beneficial food and beverage products but also encourage further understanding of the potential of bioactive compounds in ginger to support human well-being.


Introduction
Ginger (Zingiber officinale) has long been recognized as a herbal plant with promising health potential [1].Bioactive compounds such as gingerol, shogaol, and zingerone contained in ginger have attracted the attention of researchers due to their antioxidant, anti-inflammatory, and anticancer potential [2]- [4].Therefore, research on the preparation of ginger extracts is becoming increasingly important to optimize the utilization of the health potential of this plant [5].
Recently, interest in using ginger as a natural ingredient for health care has increased rapidly [6].Many studies have been conducted to identify bioactive compounds in ginger and their potential benefits for human health [7].However, integrating ginger into health products and functional foods requires high-quality ginger extracts that contain optimal levels of active compounds [8].
Extracting bioactive compounds from ginger with high yield and quality is still challenging [9], mainly when applied to the creative economy community.The extraction method can affect the extracted compounds' quantity and quality [10].In recent years, various extraction methods, such as solvent extraction, physical extraction, and high-pressure extraction techniques, have been developed to maximize the yield of bioactive compounds from ginger [11], [12].Another urgency is the ease of the process that can be implemented by MSMEs with a focus on obtaining high-quality ginger extract that still contains active compounds at optimum levels.
This research is motivated by the need to develop a conventional, efficient, easy-to-use, and economically sustainable ginger extraction method.Currently, on the market, many products contain red ginger extracts, such as health supplements, functional drinks, and beauty products.However, most of these products still require a deeper understanding of the factors affecting the quality and quantity of active compounds in ginger extracts [13].
This research focuses on developing effective and efficient ginger extraction methods to obtain extracts with high content of bioactive compounds [14].Different extraction methods, such as solvent extraction, water extraction, and high-pressure extraction techniques, will be evaluated to determine the best method that produces ginger extracts with the desired quality and quantity of compounds [15].The post-harvest handling method for ginger plants is quite applicable; however, the MSME scale has not been able to enter it, both in terms of process stages and equipment.For this reason, the research will focus on a simple process through an extraction process involving polar solvents, which are easily obtained by MSMEs.Then, the process continues with the evaporation-crystallization process to produce red ginger powder products.The role of process temperature (80 and 90 o C) and crystallization agent (sugar: 60 and 100%) will be research variables.
By understanding the importance of ginger extracts in the context of health and industry, this study is expected to make valuable contributions to the development of more efficient and applicable extraction methods, deepen our understanding of the potential properties of ginger in the field of human health and can provide practical guidance for the food, supplement, and drug industries in developing high-quality and valuable ginger-based products in the development of nature-based products for human health and well-being [16].The use of the evaporation-crystallization process by varying the temperature (80 and 90 o C) and the percentage contribution of the crystallizing material (60 and 100%) is thought to be able to produce red ginger powder products and compete with commercial products already in circulation.
In relation to the goals of sustainable development, this article provides steps and views on the implementation of the use of ginger raw materials and pulp in the form of powder or liquid products.The dissolution process using a polar solvent (easy for MSMEs), followed by the evaporationcrystallization process, will provide a green light for business activists.The resulting products also have the potential to compete with commercial products.In this way, the use of ginger as a sustainable product will be able to be applied not only by industry but also by MSMEs.

Sample collection and preparation
Red ginger is the primary raw material from traditional markets in Bekasi district -West Java, Indonesia.Providing other supporting ingredients aims to strengthen the spicy taste, color, and aroma.The raw materials were washed to release soil impurities and allowed to dry for 30 minutes.Granulated sugar, which acts as a crystallization agent (60 and 100%), comes from PT Surya Utama Sentosa Jakarta, Indonesia, obtained through the distributor PT Lotte Shopping Indonesia.

Red ginger extract preparation
The raw -supporting materials were pulverized, and distilled water was added (3:1:1 ratio, w/v) and allowed to dissolve for 1 hour.The separated liquid sample was stored under sealed conditions in a refrigerator.Then, the material dregs were added to distilled water again (1:3) with the continuation of the previous steps.The residue that was not fed to the evaporation-crystallization process equipment (80 and 90 o C) was the white residue from the primary raw material (gravity separation) and the fiber material.This method is a trial step that has been implemented in MSMEs for phase one capacity.

Proximate analysis
Determination of proximate analysis of red ginger samples (moisture, ash, fat, carbohydrate, and protein) using the Association of Official Analytical Chemists -AOAC [17] method.The way to calculate carbohydrates is by the difference method.Equation (1) was used to calculate the carbohydrate content (%), namely: Carbohydrate = 100 − (ash + moisture + fat + protein)

Total glucose
The glucose standard solution was prepared by dissolving 10 mg of glucose into 100 ml of distilled water.The concentration of this solution changed to 0; 10; 20; 30; 40; and 50 ppm.Then, each 1 ml of standard solution was mixed with 5% phenol (1 ml) and 5 ml of concentrated sulfuric acid solution by pouring quickly -perpendicular to the solution's surface and let stand for 10 minutes.The homogenization process was given and placed into the handler for 15 minutes.The wavelength of 490 nm was the absorbance measurement parameter using Genesys 150 UV-Visible Spectrophotometer equipment.Please repeat this step for the test sample by hydrolyzing it first, and 1 ml of the sample is mixed with phenol and concentrated sulfuric acid solution (the next steps are the same until the absorbance measurement with a wavelength of 490 nm).This procedure is a modification step as a form of adjusting the sample conditions by referring [18].

Total phenolic content
Determination of total phenolic content (TPC) using the Folin-Ciocalteu reagent method [19], expressed in gallic acid equivalents.

Carotenoid content
The determination of carotenoid content is based on the standard curve of carotenoids by reading the absorbance for the standard solution at a wavelength of 350-550 nm-the standard solution made from carotenoid mother liquor (1 mg/ml) in ethanol.The solution was prepared as a standard series at 3, 6, 9, and 12 µg/ml, and the maximum wavelength obtained was the absorbance measurement.Plotting the curve between solution concentration and absorbance and regression was performed.Next, 1 g of the research sample was dissolved into 25 ml of a mixture of hexane, ethanol, and acetone (2:1:1) and homogenized for 30 minutes.The homogenization process was again carried out for 2 minutes by adding 10 ml of distilled water.The result was polar and non-polar solutions.Absorption readings were taken for the separated non-polar solution.This procedure is a modification step as a form of adjusting the sample conditions by referring [20].

Antioxidant activity
The antioxidant activity of red ginger extracts and powdered products was determined using the 2.2diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay by following the work process of [21].Equation ( 2) is the step of estimating the percentage of inhibition.Notation A 0 is the absorbance value of the control, and A 0 is the test sample's absorbance.The determination of the IC50 value (ppm or %) was assisted by the calibration curve obtained from the percentage of inhibition.

Color
The CR-300 (Chromameter) method is a standard parameter for testing color characteristics [22] for both powdered products produced and commercial products in Indonesia.The acquisition of L* (brightness value), a* (red-green value), and b* (yellow-blue value) is a form of representation of the intensity and direction of color change that is visually present in the sample [23]- [26].
2.9.FTIR Shimadzu equipment, IRTracer-100, Fourier Transform Infrared Spectrophotometer was used to analyze the chemical compounds' composition in red ginger samples.The FTIR working procedure is described by [27].

Statistical analysis
Processing of proximate content, total glucose, phenolic, carotenoids, and DPPH radical scavenging activity using Microsoft Excel and Origin program for the combined curve of FTIR spectra.

Result and discussion
The processing of red ginger into powder products has three categories, namely fresh (A) and recycled pulp (B) with a temperature of 80 (numbers 1 and 2 indicate the percentage role of the crystallization agent, 60 and 100%, respectively) and 90 o C representing numbers 3 and 4 with the same regard for the involvement of granulated sugar.Labels A and B represent the powdered products after the evaporationcrystallization process with 19 rpm as the stirring speed.The dissolution of 30 g of product A into 75 and 150 ml of water is the representative form of label C. Similarly, label B against D. Indonesian commercial ginger products are also compared in the form of CPx and CPy in the solid state as well as CPxc and CPyc referring to the dissolution step.Meanwhile, label Z represents the sample before entering the equipment operating conditions.

Proximate compositions
The contents of water, ash, fat, protein, fat, and carbohydrate are the composition of the proximate analysis.The carbohydrate value is the residual subtraction from 100% of the four contents in Figure 1.
The contents of the control sample are shown in Table 1.
The product samples were subjected to proximate content testing in the solid phase (Figure 1).The powder products were stable against the treatments of operating temperature (80 and 90 o C) and crystallizing agent -granulated sugar (60 and 100%) on the distribution of proximate values (moisture content, ash, and carbohydrate).The proximate content values for both commercial products were within the range of this research product.The red ginger pulp protein content (B) decreased between 76.234-85.534%from both raw materials (A and B).The increase in carbohydrate value from sample Z to products labeled A and B was due to the evaporation to the crystallization process [28].Both process variables contributed equally to the carbohydrate content.The powdered product undergoes a dissolving treatment with 150 ml of water for human consumption.The highlighted changes are in addition to the water content.The ready-to-drink red ginger product contributed 59.308-64.418;12.741-24.112;0.102-0.279;and 48.961-52.651% of the red ginger powder product for ash, fat, protein, and carbohydrate contents, respectively.These results also align with research conducted by [29], which showed that ginger powder is very rich in ash content and followed by water content.The ash content illustrates the amount of mineral elements contained in ginger so that high ash content can indicate the content that is good for health.Protein content, which has the lowest value of other proximate test values, is most likely due to the fineness of ginger powder solids, which is still significant.This result is also in line with the results of research conducted by [30], which showed that the fineness of ginger powder could show low protein levels so that it can reduce the solubility of ginger powder.This point was also the case for the commercial product when it was dissolved, except for the ash content, which was constant for the powdered commercial product.The fat, protein, and carbohydrate contents were 62.969-63.248;0.7351-0.800;and 45.587-46.096%,respectively.The commercial product also experienced these results when reconstituted, except for the ash content, which was pretty constant for the powdered commercial product.The fat, protein, and carbohydrate contents were 62.969-63.248;0.7351-0.800;and 45.587-46.096%,respectively.
The product of processing through evaporation-crystallization equipment provides a role for business activists in Indonesia in utilizing red ginger as an economical product with conventional preparation steps.Proximate test results were able to provide equivalence with commercial products.Of course, increasing the operating temperature is an opportunity for further research to reduce process time and maintain the quality of red ginger powder products.

Carotenoid and total glucose
The results of carotenoid content (CC) for red ginger powder products are presented in Figure 2. Fresh red ginger raw materials have CC ranging from 5.243 to 5.693 g.Repeated use of processed raw materials decreases CC between 55.617-64.571%from the original material.Repeated use of the process raw material decreased CC between 55.617-64.571%from the original material condition.Dissolving the product of red ginger powder into 75 and 150 ml of water provides a dilution condition and a decrease in CC up to 0.5 and 0.25 times, respectively.According to [31], the CC reaches its highest point in the solid state because the analysis is tangent to its crystal formation.The evaporation-crystallization process time reduced the CC to 21.222-22.833% of the Z sample.However, varying the percentage of crystallizing agents at both production temperatures provided balanced values for both raw materials.Both commercial products also gave similar results for CC in solid and liquid form.
Differences in glucose levels, carotenoids, and biomass of alang-alang (Imperata cylindrica L. Beauv) growing in two different districts (Semarang -Central Java, Indonesia) were shaded [32].The results showed that reeds growing in geographical area A had higher glucose levels than in area B. rubberenoid levels also shared this increase.This increase was also shared by its rubbered levels.The cause is indicated by the difference in light intensity received by plants in both locations.Reeds growing in shaded areas tend to increase carotenoid production as an adaptation response to low light conditions.This study also revealed that reedbed A had a lower biomass than subdistrict B. The competitiveness of other plants in a shaded environment is likely indicated as a factor limiting the growth of reeds and resulting in a decrease in biomass.In simple terms, geography also provided a positive signal for the content of reeds as a reflection of plant adaptation to different growth conditions.
The results of total glucose (TG) for the red ginger powder product are shown in Figure 2.This TG level during the application of temperature and granulated sugar during the evaporation-crystallization process was 60-70 ppm.The given process traps the coarse sugar crystals in the red ginger powder.When the dissolving process was applied as a ready-to-drink product, the TG content increased by 1.098-1.288times with 75 ml of water contribution.This result applies to both raw materials and commercial products.The ready-to-drink product experienced the opposite when 150 ml of water was added to the powdered product.The TG value decreased by 68.629-84.148% of the red ginger powder product.Both types of dissolved products are still within the sugar consumption range for the human body, which does not exceed 30 g per day (or the equivalent of 30,000 ppm).
Research on the effect of drying methods on total phenols, total carotenoids, individual phenols, and antioxidant activity in ginger (Zingiber officinale) rhizomes highlighted changes in bioactive components during the process [31].This study showed that low-temperature drying or non-thermal methods tended to better preserve the phenol and carotenoid contents in ginger than high-temperature drying methods.The study also revealed changes in individual phenol components and antioxidant activity, confirming the importance of choosing an appropriate drying method to maintain ginger's nutritional quality and antioxidant properties during processing.In the drying process, dehumidification agents can also be added to reduce the water content in the air to reduce the burden of heater performance [33], [34] or foaming agents to protect the antioxidant content susceptible to the process temperature [35].

Antioxidant IC50 dan phenolic content
The phenolic content (PC) of red ginger powder samples differed by up to 50% from fresh raw materials to pulp utilization, as shown in Figure 3.The application of heat from 80 to 90 o C and the contribution of crystallization agent resulted in a relatively low PC reduction between 8.731-10.905% in both raw materials.
The evaporation-crystallization process reduced sample Z to 16.456-37.553%when the fresh and pulp raw materials were transformed into red ginger powder products.However, the dissolution of this product into 75 ml of water restored the PC value to a similar number.It even exceeded the PC value of sample Z or the range was 2.477-4.096times from solid to ready-to-drink product.The opposite occurred when 150 ml of water was involved.The PC decreased between 44.033-74.719and 77.536-82.906% of the red ginger powder product PC.
In addition to dissolving, the heating method can also be a reference to increase PC in ginger powder.Research [31] reported that different heating methods affected PC, which correlated to its antioxidant activity.The role of sugar as a crystallizing agent under 80 and 90 o C temperature conditions resulted in red ginger powder products that could hold PC in crystalline form.PC was released again when the dissolution process was given (with appropriate composition).Commercial products also experienced the same thing in solid conditions until dissolved into water.
Research [36] showed ginger extract has significant PC, contributing to its strong antioxidant activity.Measurement of the IC50 value (50% inhibition concentration) revealed that ginger extract can inhibit free radicals effectively.Furthermore, the incorporation of ginger extract in SNEDDS with eel bone oil was able to maintain the antioxidant properties of ginger.This result indicates the potential use of SNEDDS as a delivery system that allows the preservation of ginger's antioxidant activity.The antioxidant values of red ginger powder are presented in Figure 3.The antioxidant values of fresh and pulp red ginger significantly increased from 2.443 to 4.439 and 6.660 to 10.930 times of the antioxidant value of sample Z, which had not undergone the evaporation-crystallization process, respectively.Dissolving the red ginger powder product into 75 ml of water gave the same effect, increasing the antioxidant value by 1.820-2.115(fresh) and 1.133-1.193times (pulp or dreg) from the antioxidant value of the red ginger powder product.Research [31] also reported that powdered products would have a higher antioxidant effect before consumed in liquid form and other contents.
The 90 o C temperature treatment with various percentages of crystallizing agents (both fresh and pulp in powder form and ready-to-drink products) significantly affected the antioxidant value of 200.900-277.801ppm.In addition to the heating level, the stirring rotation in the crystallization process can also contribute to the high inhibition concentration factor (IC50) in the antioxidant content of red ginger powder, as stated by [37].Then, compared to commercial products, it also increases antioxidant levels from powder to liquid.
In a study on the antioxidant activity of a combination of ginger tea (Zingiber officinale) and telang flower (Clitoria ternatea L.) [38], it was found that the phenolic content in ginger contributed to strong antioxidant activity.This achievement is evidenced by the low IC50 value, where ginger significantly inhibits free radical damage.The combination of ginger and telling flower tea also showed the potential to increase antioxidant activity synergistically, as indicated by the interaction between the components in the tea.

Color
The results of testing the color characteristics of the red ginger products are presented in Figure 4 and Table 2 below.The study showed that pulp decreased the L, a, and b values compared to fresh red ginger.The increased contribution of granulated sugar during the evaporation-crystallization process at the same operating temperature also reduced the values of product color parameters.The dark colors in food will generally give humans the perception that the food is sweeter than the bright colors of the food [39].With this, a high L a b value cannot be used to reference that the product is not tasty.This statement is also supported by previous research conducted by [40] that the color of food cannot represent a taste or flavor in a food.Then, CPx commercial products are more likely to have IOP Publishing doi:10.1088/1755-1315/1324/1/01212910 similarities with the products of this study.Meanwhile, the CPy commercial product was more prominent for the b score than the other two parameters.This achievement is seen differently from the color components of label products A and B.
The pigment composition that causes the light yellow color in ginger (Zingiber officinale) rhizomes revealed that carotenoid and flavonoid pigments are the main culprits [41].Carotenoids such as betacarotene and zeaxanthin give yellow to orange shades.Meanwhile, flavonoids such as chalcones and flavonols also affect the coloration.The results of this study contribute to the understanding of the natural color of ginger and its potential use in various industries.

FTIR spectra
The wavelength distribution of the solid and ready-to-eat red ginger products is presented in Figure 5.The components of each sample are shown in Table 2.The post-evaporation-crystallization process dissolved in 75 ml of water can bring out chemical compounds not possessed by sample Z, which play a role in the pharmaceutical and food industries.These components are carboxymethyl cellulose calcium, carboxymethyl cellulose sodium salt, and magnesium sulfate.All three have functions for the health of the human body.The first is to help the absorption performance in the digestive tract and active ingredients for eye irritation products.The next component is useful as a protective colloid (stabilizer in foods).The last one provides a role for body supplements in restoring the function of organs such as the brain, heart, and muscles.Researcher [42] stated that the functional groups of ginger samples have a wavelength range between 400-4000 cm -1 .The functional groups detected at 997-3400 cm -1 are O-H (hydroxyl and phenol); C-H (both for methylene for secondary metabolite and aromatic skeleton-lignin.Other bonds in the wavelength range are C=C (referring to terpenes: zingiberene, camphene, β-elemene, limonene); and C-N, which indicates the presence of zingerines.
Other researchers detailed at ± 1000-1100 cm -1 wavelengths that there is an extension of the C-O bond associated with a carboxylic acid, alcoholic, phenolic, ester of lignin group, ether, and hemicellulose components [41] with aromatic groups CH2 at ± 1500-1650 cm -1 [43], [44].Meanwhile, other researchers found these functional groups on the surface of red ginger [43].The application of FTIR helps indicate changes in the composition of food, known as an early reference for the feasibility of food for consumption and an effort to avoid indications of other harmful additives [45].

Figure 2 .
Figure 2. Carotenoid and total glucose content of red ginger powder.

Figure 3 .
Figure 3.The DPPH radical scavenging activity and phenolic content of red ginger powder.

Figure 4 .
Figure 4. Color of the final products.

Table 1 .
Content of sample Z (liquid) before feeding to evaporation-crystallization equipment.

Table 2 .
Color values in various red ginger powder products.