Pineapple Skin Research Articles

Green Degumming of Silk by Enzyme Extracted from Natural Sources

The main objective of this work is to degum the silk with natural enzyme in lieu of conventional degumming to make it sustainable. Fibroin and sericin are the main composition of silk. Sericin provides a harsh and stiff effect of silk and decreases the valuable property like luster and whiteness and also leads to uneven dyeing. It is necessary to remove this sericin for the better post processing of silk. The removal process of sericin from silk is called degumming. Usually degumming process is done by using chemicals like soda (Na2CO3), detergent and other chemical staffs. But these chemicals are lethal to the environment. So, if such component found that can be substitute the fatal components and give the same required result or very close then that would be considered as an asset. This work deals with the different enzymes extracted from natural sources such as papaya skin, pineapple skin and guava leaf with variation of enzyme concentrations such as 10 (%), 15 (%) & 20 (%) as well as 35°C 45°C & 55°C temperatures that influence the degumming efficiency. By analyzing the various samples on the basis of degumming efficiency and other tests such as tensile strength, water vapor permeability, pilling and abrasion, crease recovery, whiteness test and spot test are done by standard method, it is found that the enzyme extracted from papaya skin shows the best degumming efficiency 15.9 (%) and other tests also show the good result at 15 (%) concentration and 45°C temperature whereas degumming efficiency 16.6 (%) for conventional process. From this work, it can be concluded that enzyme extracted from papaya skin can be substituted of conventional degumming which is also ecofriendly.

The effects of hand soap making practice with addition of pineapple skin extract (Ananas comosus L. Merr) on learning interests in colloidal materials in senior high school

Learning by practicum method is a way of delivering learning material by providing opportunities to the students to practicein order to make the students engage in planned and active learning experiences so that students' interest grows on chemistry subject. The population in this study were the students of XI class at YAPSI Senior High School in Medan. The sampling technique is done by using the Quota sampling technique. The instruments were the student’s interests in questionnaire and student activeness observation sheet. The requirements test is in the form of normality test and homogeneity test with the value of L count = 0.663 initial interests data and L count = 0.172 final interests data which means the data is normally distributed. In the homogeneity test F count = 0.233 initial interests data and F count = 0.449 final interests data with homogeneous results. The data analysis technique was done by using the hypothesis t test and N-gain test. The results showed that the hand soap making practice with the addition of pineapple extract ( Ananas comosus L .. Merr) had an influence on students’ learning interest with N-gain of 7.6 in experimental class data and N-gain of 5.4 in control class data and from the t hypothesis test obtained T count > T table which T count = 6.90 and T table at level 0.05 is 2.01 so H o is accepted, which means that there was an influence of the handsoap making practice with the addition of pineapple skin extract ( Ananas comosus L. Merr) on student interests in learning. Keywords: Colloid; hand soap making practice; interests

Profile of Sinjai Superior Kampong Chicken (SSKC) Meat Colour Marinated with Pineapple Skin Powder

Kampong chicken is one of the local poultry that is generally raised by farmers in rural areas; the Kampong chicken farm business has great prospects, both economically and socially, because its products in the form of meat and eggs are highly nutritious food and high enough demand. The provision of pineapple skin was expected to be able to improve the quality of livestock products through enhancing the profile of SSKC meat colour that was contained in it, so it was necessary to do research on the effect of giving pineapple skin as a marinated meat ingredient for SSKC. Pineapple skin in this study was given in powder form to improve the profile of meat colour. The stages of this study carried out the process of marinating used pineapple peel powder with the specified marinating time. The samples were tested for colour profiles by measuring the brightness, redness and yellowish level of the flesh. The results showed that the colour profile was increasing with increasing levels of pineapple skin powder and marinating time. Based on these results, it can be concluded that the optimum profile of SSKC meat colour was at the level of 20% during soaking 120 minutes.

Skrining Fitokimia Ekstrak Etanol Kulit Nanas (Ananas comosus (L.) Merr)

Pineapple (Ananas comosus (L.) Merr) is one type of fruit that is in demand by the community, both local and world. Pineapple has a waste part that is skin. Pineapple skin in Indonesia is generally just thrown away as waste, whereas pineapple skin contains chemical compounds that are known to have properties. The purpose of this study was to determine secondary metabolite compounds found in pineapple skin. This type of research is descriptive qualitative. Then the method used is phytochemical analysis. The Positive test of this method is characterized by a change in color. Pineapple skin samples were taken from Samarinda, East Kalimantan. The extract was carried out by maceration of dry samples using 96% ethanol solvent. The results of the pineapple skin extraction are then carried out phytochemical screening tests using certain reagents. Phytochemical screening tested included flavonoids, alkaloids, steroids, triterpenoids, tannins, phenolics, and saponins. Based on the results of phytochemical screening research, positive pineapple skin extracts contain flavonoids, alkaloids, tannins, and saponins, while negative results contain phenolic compounds, steroids, and triterpenoids.

Gambaran Hasil Aktivitas Antioksidan Berberapa Perlakuan Teknik Preparasi Pembuatan Konsentrasi Ekstrak Kulit Buah Nanas (Ananas comosus L.Merr) Menggunakan Senyawa DPPH (1,1-diphenyl-2-picrylhydrazyl)

Pineapple skin (Ananas comosus L.Merr) has been known to have a category of strong antioxidant activity against reducing DPPH compounds (1,1-diphenyl-2-picrylhydrazyl). However, references to the preparation process of extract concentration making and the treatment of DPPH compounds to extracts are not much elaborated, so that it can cause errors in inferring the category of antioxidant activity. The purpose of this study was to determine the results of antioxidant activity through the treatment of preparation techniques for the concentration of pineapple peel extract concentration. Pineapple peel extract (Ananas comosus L. Merr) was prepared by maceration method using 70% ethanol solvent. Testing of antioxidant activity was carried out using the UV-Vis spectrophotometric method at a wavelength of 516.4 nm. The extract concentration to be tested was 500 ?g/mL, 250 ?g/mL, 125 ?g/mL, 62.5 ?g/mL and 31.25 ?g/mL and the concentration of DPPH compounds (1,1-diphenyl-2-picrylhydrazyl) was 45 ?g/mL. Treat the extract making concentration divided into 3 namely P1 (multilevel dilution with a volume ratio of 1: 1) P2 (normal dilution with a volume ratio of 1: 1) and P3 (DPPH solution is used to suffice the volume of the extracted test extract). The results of percent inhibitors from each treatment of making concentrations showed P1 <P2, P1 <P3, P2 <P3, and IC50 of each treatment were P1 268.07 ?g/mL, P2 was 231.28 ?g/mL, P3 was 78.403 ?g/mL. Based on the results of IC50 P3 gives the category of antioxidant activity that is 78,403.Keywords: pineapple fruit skin (Ananas comosus L. Merr), antioxidants, dpph (1,1-diphenyl-2- picrylhydrazyl), dilution.

Comparison of Antioxidant and Anti-Tyrosinase Activities of Pineapple (Ananas comosus) Core Extract and Luteolin Compound

Free radicals and UV exposure can cause aging. Aging prevention needs substances that can prevent molecular oxidation reactions in cells and inhibit the activity of enzymes that trigger aging. Research on pineapple skin and flesh extract (Ananas comosus (L.) Merr.) reported the presence of luteolin compound which functions as antioxidants and antityrosinase. However, in this study, the object used was pineapple core extract (PCE), which has not been widely known for its antioxidant and antityrosinase activity. Therefore, the purpose of this study was to determine the content of phytochemical compounds, antioxidant activity, and inhibitory activity of tyrosinase enzymes by PCE and then compared with the luteolin (LT) compound test results using Fansworth method, DPPH scavenging activity assay and tyrosinase enzyme inhibition assay. Based on the study results, the phytochemical compounds contained in PCE were tannins and triterpenoids. PCE and LT produced the highest DPPH scavenging activity, which was 64.86% and 59.32% (final concentration 200μg/ml and 6.25μg/ml) and the highest tyrosinase inhibition activity, which was 60.52% and 85.02% (final concentration 100 μg/ml). Antioxidant activity was determined based on IC50 of 87.46µg/mL and 4.17 µg/ml respectively. IC50 tyrosinase enzyme inhibition EBN and LT respectively at 62.27µg/ml and 5.25 µg/ml. Antioxidant activity through DPPH free radical scavenging test and tyrosinase enzyme inhibition activity by PCE was lower than LT.

Efektivitas Penggunaan Bokashi Blotong Tebu dan Pemberian Pupuk Organik Cair Kulit Nanas Terhadap Produktifitas Tanaman Kecipir (Psophocarpus tetragonolobus L.)

Cowpeas is becoming rare, hence it has to be planted again to some reasons. This research aims to know the growth and production of cowpeas with Bokashi use of sugarcane filter cake and liquid organic fertilizer pineapple skin that have been implemented at the Faculty of Agriculture Experimental Station Road PBSI Area Terrain 1 Terrain Estate, District Percut Sei Tuan from March to July 2019. Methods the research in this research is a randomized block design factorial, with 2 (two) treatment factors, namely: 1) factors bokashi cane filter cake (T) and Organic Liquid Fertilizer Factors pineapple skin (S), each treatment was repeated 2 times so that there are 32 experimental plots. Each experimental plot consisted of eight plants with four plant samples. The results of this research indicate that the use of Bokashi blotong cane very significant effect on the number of pods persample but did not significantly affect stem diameter, length of pods persampel, heavy pods persampel and production perplot, fertilizer liquid organic pineapple skin very significant effect on the number of pods persampel, but did not significantly affect stem diameter, persampel pod length, pod weight and production persampel perplot, a combination of the use of sugarcane filter cake bokashi organic fertilizer liquid and pineapple skin no real effect on the growth and yield of cowpeas.

The application of different Bacillus subtilis contained formula as bio fungicide tablet to control Ganoderma boninense in oil palm nurseries

This study aimed to determine effect of different Bacillus sp. endophytic contained formula as bio fungicide tablet to control Ganoderma boninense in oil palm nursery. A Complete Randomized Design, 5 treatments and 4 replicates were used. The treatments were different formula namely: F0 = Bacillus sp. endophytic, F1 = Bacillus sp. endophytic + sago starch + peat + tapioca flour, F2 = Bacillus sp. endophytic + corncobs flour + sago dregs + tapioca flour, F3 = Bacillus sp. endophytic + solid + talk + tapioca flour, F4 = Bacillus sp. endophytic + pineapple skin flour + zeolite + tapioca flour. Data were analyzed using ANOVA at a = 5%. The results showed that all formulas were able to slow down incubation period and reduce disease intensity. However, the increase of seedlings height, number of leaves, increase in tuber diameter, root volume, root canopy ratio and dry weight of roots is not affected. F3 was found as best formula due to able control G. boninense by slowing down disease incubation period and reduce its intensity to 0% within 140 days. That formula also shows better in increasing seedling height, number of leaves, diameter of stem, root volume, and weight dried root.

Bacterial Cellulose-BasedBiodegradable Plasticfrom Pineapple (Ananassativus) Skin Waste: The Effectof Sorbitol On The QualityOf The Biodegradableplastic

The aim of this research was to investigate the effect of sorbitol on the quality ofbacterial cellulose-based biodegradable plastic from pineapple skin waste. Various concentrations of sorbitol as the plasticizer were added into a fermentation medium in the synthesis of bacterial cellulose-sorbitolcomposite (BCSC). The BCSCobtainedwas purified by soaking it into a cycled water-NaOH-water. The purified BCSC wasthen compressed using a hot press with the pressure of 300 psi to obtain BCS plastic. The BCS plasticwas characterized in the aspect of physical properties (water content,the degree of swelling), mechanical properties (tensile strength,elongation, elasticity), molecular structure (functional groups, thedegree of crystallinity), and biodegradability. The results showed that the percentage ofwater content anddegree of swelling of theBCS plastic increased with the addition of sorbitol concentrations. The maximum tensile strength was obtained with the addition of 10.5% sorbitol (%v/v). The degrability of the BCS plastic was up to 59% until the 9th day. TheFTIR results showed that functional groups appeared in the BCS plastic were similar to those of the BC. The degree of crystallinity of the BCSplastic decreased with the increasing concentration of sorbitol.

Physical and Chemical Characteristic of Halal Gelatin Extracted from Buffalo Hide with Addition of Pineapple Rind at Different Ratio

The production of halal gelatin from buffalo hide waste which is animal be slaughtered according to Islamic law and using pineapple rind as an extraction agent was an alternative to produce halal gelatin. The availability of buffalo hide in Riau Province was stable and its hide had high protein content. This research was conducted to produced and determine the characteristics of halal gelatin from buffalo hide using solution of pineapple skin in terms of their physical and chemical properties. The Completely Randomized Design (CRD) was experimental design used with consist of 3 treatments and 4 replications. The treatment was ratio hide : pineapple rind solution, namely 3:1, 3:2 , 3:3 w/v. The parameters observed were yield, viscosity, color, pH, ash content and moisture content. The results showed that immersion of buffalo hide in the solution of pineapple rind at different ratio gave highly significant increased the viscosity and ash content of gelatin but not significant effect to yield percentage , color, pH and moisture of gelatin. The yield percentage ranging from 5.99-7.33%, pH 4.83-4.85, viscosity was 1.95-2.20 cP, color 0.54-0.71 absorbance unit, ash 0.25-, 032% and moisture 9.97-9.99%. It can be concluded that the best treatment was ratio 3:2 and 3 : 3 according to had viscosity, pH, color, ash and moisture in line with the standard of gelatin by Gelatin Manufacture Institute of America (GMIA).

Utilization of Bromelain Enzyme from Pineapple Peel Waste on Mouthwash Formula Against Streptococcus mutans

The aim of this research was to apply bromelain enzyme from rough extract of Ananas comosus (L.) Merr. peel into the mouthwash preparation and investigate the enzyme activity to inhibit Streptococcus mutans growth.. The research method, bromelain was extracted by means of a blended pineapple skin, the extract was filtrated and centrifuged to obtain a supernatant. Enzyme activity was analyzed by spectrophotometer at 275 nm. Mouthwash formula which involved different concentration of bromelain (20%, 25%, 30%, 35%, 40%, 50%, and 60% (v/v)) was tested the antimicrobial activity by disc diffusion method. The results showed that the formula with 35% enzyme was an effective in restricting the growth of Streptococcus mutans, with a relative potential value of 100.40% compared to Chlorhexidin 0.1% as possitive control.

Oil and Water Absorption Behavior of TPU/Natural Fibers Composites

Fruit skins are waste and natural fibers which are processed from it can be used as filler material in polymer composites. These natural fibers are surely inexpensive, non-toxic and environmentally friendly. In the other hand, natural fibers are chemically hydrophilic and absorb water. Their nature which are rich cellulose making it hydrophilic in nature. Besides their nature to water, the ability of natural fibers to absorb oil also interesting to be studied. In this paper, natural fibers from several types of fruit skin were used as filler in thermoplastic polyurethane (TPU) composites. The fibers from pineapple skin, coconut shell, coconut husk, corn cob, rambutan, mangoesteen and banana with the percentage of 15% and 20% were incorporated with TPU through melt mixing technique. Every type of natural fiber will absorb oil and water at different rate, as well as the effect of filler content in the composite. Overall, the absorption of water and oil increased its percentage when the filler content increases. Rambutan, pineapple and banana absorb more water than others at 20% filler content in the TPU. Pineapple and rambutan also tend to absorb more engine oil.

Perbandingan Penambahan Bioaktivator EM-4 (Effective Microorganisme) Dan Mol (Microorganisme Local) Kulit Nanas (Anana Comosus L.Merr) Terhadap Waktu Terjadinya Kompos

The Comparison Of Additional Bio-Activator EM-4 (Effective Microorganism) And Mol (Microorganisme Local) Pineapple (Ananas Comosus L.Merr) Skin To The Composting Time. Composting is the reform process (decomposition) and stabilization of organic materials by microorganism in controlled environment (controlled) and its final outcome of humus or compost. It can be speed up by addition other ingredients called the activator. Activator is material consisting of enzymes and microorganisms (bacterial culture) that can accelerate the composting process. This study aimed to determine the effect of additional bioactivator EM-4 (Effective Microorganism) and MOL (Microorganism Local) pineapple skin (Ananas comosus l.merr) skin to the composting time. They was administered on each treatment and observed for 24 day. The result of the compost with the addition bio-activator EM-4 took for 16 days and compost with the addition MOL pineapple skin took for 14 days. Based on the statistical analysis by One Way Analysis of Variance method with α = 0.05 was significant effect between the addition of bio-activator EM-4 and MOL pineapple skin to the compositing time with average composting time for 16 and 14 days. Further study can be conducted by potential materials as basic raw materials for MOL such as fruits (banana, sugar cane, jackfruit), animal and human urine, and food scraps.

PEMBUATAN DAN KARAKTERISASI METIL SELULOSA DARI BONGGOL DAN KULIT NANAS (Ananas comosus)

[MAKING AND CHARACTERIZATION OF CELLULOSE METHOD OF BONGGOL AND LEATHER LEATHER (Ananas comosus)] Wastes of core and peel of pineapple are often not utilized properly, in fact the waste has nutritional content that can be useful. Carbohydrate content in the waste is large enough and allows to be utilized. The purpose of this research is for converting glucose into cellulose and synthesized into methylcellulose. The first stage is glucose from core and peel of pineapple converted into microbial cellulose with Acetobacter xylinum bacteria with the addition of nitrogen and carbon sources. The second stage is synthesis of methylcellulose with methylene chloride and the solvent aquadest/acetone. The dried microbial cellulose was firstly swelled with NaOH addition, then methylation by addition of solvent and methylene chloride and then refluxed at 50-60. Then methyl cellulose neutralized, washed and dried at 50.The FTIR results showed typical cellulose uptake for cellulose microbial pineapple core at wave number 3377.36 cm-1 for OH bonds and 2935.66 cm-1 for CH bonds and in cellulose microbialpineapple peel at wave number 3377.36 cm-1 for OH bonds and 2935.66 cm-1 for the CH bonds. The ratio OH/CH of methyl cellulose-acetone has a smaller value in the core and peel of pineapple concluded that acetone is more efficient to use as a solvent at the methylation. The substitution value of the core and peel of pineapple skin is estimated to below based on the solubility test results.

EFEKTIFITAS EKSTRAK ETANOL KULIT NANAS (Ananas Comosus L. Merr) terhadap Trichophyton mentaghrophytes

Ringworm of the skin caused by a Trichophyton mentaghrophytes, Drugs that are commonly used are synthetic drugs, synthetic drugs can have a negative impact. By because it, research on natural antifungal substances continue to do that with the use of pineapple skin.A pineapple skin waste processed pineapple industry, namely the remainder of the meat and fruit contains secondary metabolites are flavonoids, phenolics, saponins, triterpenoids, steroids and alkaloids. The purpose of this study to determine the content of secondary metabolites contained in the pineapple skin and for the inhibition of Trichophyton mentaghrophytes using experimental laboratoryin vitro. Pineapple bark extract prepared in various concentrations of 10%, 15%, 20% and 25%, then test the inhibition ofTrichophyton mentaghrophytesand incubated temperature 25o C for 5day. Based on the results obtained percentage pineapple skin extractfungal inhibition test Trichophyton mentaghrophytesthe concentration 10%, 15%, 20% and 25%, respectively, are22%, 37%, 46% and 56% compared to the positive control.Based on this research, pineapple bark extract containing flavonoids, phenolics, saponins, triterpenoids, steroids and alkaloids. The results of this study can be concluded that the extract of pineapple skin Trichophyton mentaghrophyteswhich is characterized by the formation of inhibit zone.

Pengujian Kandungan Unsur Hara Pupuk Organik Cair (POC) Limbah Kulit Nenas

This research was conducted at the Laboratory of Faculty of Agriculture, University of Lancang Kuning. The study was conducted for 3 months from September to November 2015. This study is a descriptive research, where the first process is the process of making organic fertilizer derived from pineapple skin waste fermented for 1 month POC that has been taken samplenya and tested in the laboratory to determine the content of micro and macro nutrients and C-organicnya. To measure macro and micro nutrient content, the test method used was Kjeldahl for nitrogen content, while for P, K, CaO, MgO and Fe, the Atomic Absobtion spectrophometric (AAS) method was used and the C-organic content was tested by spectrophometric method. The results showed that POC of Pineapple Skin Waste contained P 23,63 ppm, K 08,25 ppm, N 01,27%, Ca 27,55 ppm, Mg 137,25 ppm, Na 79,52 ppm, Na 79, 52 ppm , Fe 1,27 ppm, Mn 28,75 ppm, Cu 0,17 ppm, Zn 0,53 ppm and C Organic 3,10%.

Comparing Various Type of Natural Fibers as Filler in TPU: Mechanical Properties, Morphological and Oil Absorption Behavior

The idea of using natural fibers as filler in various polymers has been extensively studied. Various types of natural fibers and polymers have been identified and it can be varied according to the particular application and the two main composite materials will have advantages and disadvantages of each. However, natural fibers are usually selected as filler because it is readily available and environmentally friendly, inexpensive, non-toxic, biodegradable and still have good characteristics for a variety of uses. In this study, four types of natural fiber have been used which; coconut shell, coconut fiber, corn cob, and pineapple skin, as fillers in thermoplastic polyurethane (TPU). The mixing process conducted through melt mixing techniques. The percentage of TPU and natural fibers are 100/0, 95/5, 90/10 and 85/15. Different type of fiber will affect the mechanical properties of the composites and have been studied through tensile testing. It showed that the result for pineapple fiber at 5% was the highest and can also be related to the characterizations of this composite that have been studied via the SEM morphology. Swelling testing is also having been done to prove the absorbency ability by natural fiber composites in cooking oil and engine oil. Then it concluded that the pineapple fiber absorbed large amount of both oil compared to others.

Leaching Behaviour of Organic Materials in Reinforced Concrete Artificial Reef with RAC

This paper reports the leaching behaviour of pineapple skins incorporated in the artificial reef fabricated from recycle aggregate concrete. Pineapple skin was mixed with the concrete as added material which produce nutrients to attract fish habitat. Material test was conducted on the concrete reef specimens to determine its compressive strength. The nutrients dispersed were measured by using total phosphorus and nitrate test of the water sample collected from each of the artificial reef within the six days duration. Results showed the compression strength of the reef decreased with the increase of percentage pineapple skin used. However, it was found that the total phosphorus and nitrate leached from the reef increased gradually with time as the percentage of pineapple skin used increased.

Bio-Alcohol from Anaerobic Co-Digestion of Agriculture and Animal Wastes

Background/Objectives: Efficient management of organic waste is necessary to avoid negative impacts on the environment and highly potential to be converted into biofuel. The objective of this study was to conduct preliminary analysis of organic wastes that used for biofuel production and characterization of bio-liquids produced. Methods/Statistical Analysis: Cow dung, pineapple peel, vegetable waste, fish waste and leftover chicken were used in production of methanol from methane system using anaerobic co-digestion method conducted at room temperature, pH 6.4-7.0 for 19 and 30 days in 500 mL of bio-reactor. Gas Chromatography Thermal Conductively Detector (GC-TCD) was used in determination of methane while bio-alcohol formed was detected by High Performance Liquid Chromatography (HPLC). Findings: Co-digestion of R2 (cow dung mixed pineapple skin) produced highest methane (23.07% wt), bio-methanol (19.08 g/L), bio-ethanol (51.30g/L) and glucose (35g/L). This study proved that co-digestion of organic wastes able to produce biogas and bio-alcohol better than digestion of only one substrate. Application/Improvements: The upgrading stage of bio-liquid produced is required to optimize the yield of the bio-liquid and increasing the productivity in large scale study so that it will be qualified for biofuel application.

UTILIZATION OF PINEAPPLE LEATHER WASTE (ANANAS COMOCUS) AS AN OKSALATE ACID SOURCE TO IMPROVE THE EFFECTIVENESS OF Cu (II) IONALIZED ION PHOTOREDUCTION OF TiO2

A study has been carried out on the effect of the addition of TiO2 photocatalysts and oxalic acid sourced from pineapple skin at various pH and concentrations, to the effectiveness of Cu (II) ion photoreduction catalyzed by TiO2. The photoreduction process was carried out by irradiating the mixture consisting of a solution of Cu (II) ion and TiO2 photocatalyst powder without or in the presence of oxalic acid in a closed reactor equipped with a UV lamp with stirring. The photoreduction process conditions are 50 mL of 10 ppm Cu (II) ion solution (0.157 mmol / L) and varying concentrations of oxalic acid, and 20 mg of TiO2, with a 24-hour reaction time. The photoreduction product was determined based on the difference in the initial Cu (II) ion concentration and the remaining Cu (II) ion concentration in the solution after the photoreduction process was determined by the Atomic Absorption Spectrophotometry (AAS) method. The results showed that the addition of TiO2 could increase the effectiveness of Cu (II) ion photoreduction from 9.03% to 43.22%, which was initiated by the adsorption process. The presence of oxalic acid in pineapple skin in a photoreduction reaction system with greater concentration causes a relatively high increase in Cu (II) ion photoreduction because oxalic acid can prevent recombination of electrons with OH radicals, so that the Cu (II) photoreduction process can run optimally due to the amount of relatively large number of available electrons.