Article Per Year (5 Year)
p-Index From 2021 - 2026
1.066
P-Index
This Author published in this journals
All Journal Jurnal Riset Kimia Indonesian Journal of Chemistry REACTOR : Journal of Research On Chemistry And Engineering Andalasian International Journal of Agricultural and Natural Sciences Andalasian International Journal of Applied Science, Engineering, and Technology Jurnal Abdi Inovatif : Pengabdian kepada Masyarakat
Yefrida -
Unknown Affiliation
Agriculture, Biological Sciences & Forestry Humanities Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Environmental Science Industrial & Manufacturing Engineering Mechanical Engineering Social Sciences Other

Published : 16 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 16 Documents
Search

 1   2 
VALIDASI METODA PENENTUAN ANTIOKSIDAN TOTAL (DIHITUNG SEBAGAI ASAM SITRAT) DALAM SAMPEL JERUK SECARA SPEKTOFOTOMETRI DENGAN MENGGUNAKAN OKSIDATOR FeCl3 DAN PENGOMPLEKS ORTO-FENANTROLIN Yefrida -; Mega Ulfaningsih; Umiati Loekman
Jurnal Riset Kimia Vol. 7 No. 2 (2014): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v7i2.187

Abstract

ABSTRACTAntioxidant is a compound that can be used to obstruct species oxygen reactive, speciesnitrogen, and other free radicals so it can be used degenerative illnesses inhibition. Citric acid isa natural antioxidant that can be found in some kind of oranges. There are some methode thatusually used to determination the antioxidant, such as CUPRAC, DPPH, and FRAP. Objectiveof this research is studied about alternative method to determine total antioxidant that is countedas citric acid by using FeCl3 as an oxidator and o-phenantroline as a complexant reagent. Instudied of appropriateness of this method, validation has been done with parameter linearity,LoD, LoQ, SDR, and recovery with samples orange, kaffir lime, and lime. Base on the research,the regression equation is Y = 0,066 + 117.35 X and R2 = 0.990 with value of LoD is1.15x10-3M and LoQ is 3.86x10-3 M. The value of SDR and recovery in samples orange, kaffir lime, andlime are 1.64%, 0.53% 2.14%, and 100.47%, 93.58%, 93.78%, respectively. Base on validationmethod data, can be concluded that this method appropriate to be used to determination of totalantioxidant for samples orange, kaffir lime, and lime.Keywords : Antioxidant, Validation Method, Spectrophotometry
WORKSHOP PENGUATAN KOMPETENSI SISWA SMA DI KOTA PADANG MENUJU OLIMPIADE SAINS NASIONAL (OSN) IPA DAN MATEMATIKA TINGKAT NASIONAL Mildawati, Mildawati; Solfiyeni, Solfiyeni; Mairawita, Mairawita; Febria, Fuji Astuti; Ilham, Muhammad Samudra; Zulfi, Zulfi; Yefrida, Yefrida; Imelda, Imelda; Muttaqin, Afdhal; Narwen, Narwen; Efendi, Efendi; Syafwan, Mahdivan
Jurnal Abdi Inovatif : Pengabdian kepada Masyarakat Vol. 3 No. 1 (2024): Jurnal Abdi Inovatif : Pengabdian kepada Masyarakat
Publisher : Universitas Nusa Bangsa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31938/jai.v3i1.617

Abstract

The National Science Olympiad (OSN) is a prestigious event that involves the best students from various levels of education who have passed a rigorous selection at the district and provincial levels. One way to improve the quality of students in facing the OSN in Science and Mathematics is through structured coaching. The OSN Science and Mathematics Workshop held around the UNAND campus in Padang City is one such effort that has proven successful. The objectives of this workshop include three main aspects, namely improving the competence of high school students in basic science and mathematics, improving students' skills in solving OSN questions and improving the quality of high school education in Padang City. The workshop consisted of three main stages: planning, implementation, and evaluation. In the planning stage, OSN questions from the previous year were collected to be used as learning materials. The implementation stage involved a series of activities, including a pre-test, structured learning through lectures, question simulations, and discussions using audiovisual aids. The evaluation was conducted through a post-test to measure the improvement of students' understanding after attending the workshop. The results of this workshop showed a significant increase in the understanding of students who had participated from 30% to 60%. This illustrates the effectiveness of a sustainable and structured approach in improving student competencies to face OSN competitions in Science and Mathematics. This workshop could become a model for efforts to improve the quality of education in schools around the campus. It can be an inspiration for other educational institutions. Keywords: National Science Olympiad (OSN), Senior High School, workshop Abstrak Olimpiade Sains Nasional (OSN) adalah ajang prestisius yang melibatkan siswa-siswa terbaik dari berbagai tingkatan pendidikan yang telah melewati seleksi ketat di tingkat kabupaten dan provinsi. Salah satu cara meningkatkan kualitas siswa menghadapi OSN bidang IPA dan Matematika adalah melalui pembinaan terstruktur. Workshop OSN IPA dan Matematika yang diselenggarakan di sekitar kampus Universitas Andalas (UNAND) di Kota Padang adalah salah satu upaya yang telah terbukti berhasil. Tujuan dari workshop ini mencakup tiga aspek utama, yaitu meningkatkan kompetensi, keterampilan, dan mutu pendidikan siswa SMA dalam ilmu dasar IPA dan Matematika di Kota Padang. Workshop ini terdiri dari perencanaan, pelaksanaan, dan evaluasi. Pada tahap perencanaan, soal-soal OSN dari tahun sebelumnya dikumpulkan sebagai bahan pembelajaran. Tahap pelaksanaan, dilakukan pre-test, ceramah, simulasi soal, dan diskusi dengan peralatan audiovisual. Evaluasi dilakukan post-test untuk mengukur tingkat pemahaman siswa setelah workshop. Hasilnya, terjadi peningkatan signifikan dalam pemahaman soal OSN, yaitu dari 30% menjadi 60%. Hal ini menggambarkan efektivitas pendekatan berkelanjutan dan terstruktur dalam meningkatkan kompetensi siswa untuk menghadapi kompetisi OSN bidang IPA dan Matematika. Workshop semacam ini berpotensi menjadi model upaya peningkatan kualitas pendidikan di sekolah sekitar kampus dan dapat menjadi inspirasi bagi lembaga pendidikan lain. Kata Kunci: Olimpiade Sains Nasional (OSN), SMA, workshop
Optimization of Producing Zein Clove Leaf Essential Oil Nanoparticles for Their Antioxidant Activities Refilda, Refilda; Ramadani, Mutia; Nasution, Ainun; Imelda, Imelda; Yefrida, Yefrida; Batubara, Irmanida
Andalasian International Journal of Agriculture and Natural Sciences (AIJANS) Vol. 5 No. 01 (2024)
Publisher : Lembaga Penelitian dan Pengabdian, Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/aijans.v5.i01.9-20.2024

Abstract

Essential oils are often also referred to as flying oils produced by plants and usually volatile essential oils at room temperature, one of the essential oils with many uses is clove leaf essential oil (Syzygium aromaticum L). Zein-essential oil nanoparticles were prepared by varying the concentration of clove oil (0, 2, 4, 6, 8, and 20 mg/mL) added to 1.5 mg/mL zein and 1 ml tween 20 and sonicated for 20 minutes. The antioxidant activity of the zein-essential oil nanoparticles formed was tested using the DPPH method. The best antioxidant activity was found in the addition of clove leaf essential oil 8 mg/mL with a percentage of inhibition of 71.13%. Characterization test with a laser beam where the amount of light scattered by the solution. Chemical component analysis using Gas Chromatography Mass Spectrophotometry (GC-MS) showed the presence of 32 compounds with three main compounds, namely trans-?-caryophyllene (46.69%), chavibetol (25.80%) and - humulene (10.84%).
Optimasi Pemanfaatan Katalis TiO2/Karbon Aktif (Sekam Padi) Untuk Degradasi Methyl Violet Secara Sonolisis dan Fotolisis Safni, Safni; Aldini, Tasya; Yefrida, Yefrida; Zilfa, Zilfa; Deliza, Deliza
REACTOR: Journal of Research on Chemistry and Engineering Vol 5, No 2: December 2024
Publisher : Politeknik ATI Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52759/reactor.v5i2.156

Abstract

The textile industry is a major contributor to pollution, with 10-15% of dyes lost in wastewater during processing, including Methyl Violet. The degradation products of these dyes are often carcinogenic. Conventional biological treatment methods are ineffective due to the complex nature of synthetic dyes. A study aimed to develop a new photocatalytic activity using a UV A lamp and sonolysis using a sonicator. The study modified TiO2/Activated Carbon from Rice Husk as a catalyst to degrade Methyl Violet and textile industry effluent effectively, which was dual benefits as an adsorbent-photocatalyst. Results showed that the degradation by sonolysis and photolysis was 12.99% and 79.16%, respectively. The degradation by photolysis was 14.95% and 94.12%. The light and catalyst with the highest percentage of degradation were TiO2/activated carbon with UV A light of 94.12%. This study aims to develop effective treatment techniques for the textile industry's dyes.
A mixture of Aloe Vera Gel (Aloe vera. L) and Sungkai Leaf Extract (Peronema canescens. Jack) as Edible Coating to Increase Tomato (Solanum lycopersicum) Storage Life Yefrida, Yefrida; Boneta, Fella Krisna; Refilda, Refilda
Andalasian International Journal of Applied Science, Engineering and Technology Vol. 4 No. 2 (2024): July, 2024
Publisher : LPPM Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/aijaset.v4i2.122

Abstract

Tomatoes are climacteric fruits, are well-known for containing lycopene is an antioxidant. The post-harvest shelf life of harvested tomatoes is only 4-5 days. This research aims to optimize previous methods such the use of plastic packaging and cold storage methods were found to be inefficient and produced waste, so it is necessary to renew them by using the edible coating method, a natural ingredient from Aloe vera. L gel, while sungkai leaf extract (Peronema canescans. Jack) shows the effectiveness of edible coating could potentially provide a protective barrier against external factors, helping to maintain the quality of tomatoes and waste reduction. Edible coating material from aloe vera gel added with sungkai leaf extract of various compositions (C, EC1, EC2, EC3, EC4, and EC5) was prapare and applied to tomatoes. Fourier Transform Infrared (FTIR) testing was carried out to determine the functional groups in all edible coating materials. Physicochemical properties tests were carried out on tomatoes. The results obtained by EC5 the lowest weight loss 11.14%, while EC4 was the best edible coating material in percent decay 8.89%, total dissolved solids 1.00oBrix, total antioxidant 0.024 mg AA/g FW, and total phenolic 0.224 mg GAE/g FW for 15 days compared to aloe vera gel coating (EC1), which only lasted for 9 days, and uncoated (C), which only lasted for 6 days. Keywords: Edible coating, physicochemical properties, FTIR
Development and Characterization of Edible Coating Potato Peel Starch (Solanum tuberosum L.) and Sungkai Leaves Extract to Prolong the Shelf Life of Strawberries (Fragaria sp.) Ardiani, Ajeng Putri; Yefrida, Yefrida; Refilda, Refilda
Indonesian Journal of Chemistry Vol 25, No 5 (2025)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.105258

Abstract

This study developed and characterized edible coatings from potato peel starch (Solanum tuberosum L.) to prolong the shelf life of strawberries (Fragaria sp.). Due to its high starch content, the edible coating was formulated using potato peel starch as the base material, and Sungkai leaf extract was added to enhance its antioxidant properties. The coating was characterized by viscosity, pH, color, antioxidant content, and thickness; and analyzed using FTIR, XRD, and SEM. The coating was applied to strawberries, and its effectiveness was evaluated based on weight loss and decay rate during storage. The edible coating was characterized by lower viscosity (10 cP), lower pH (6.83), darker color indicating bioactive compounds, and higher antioxidant content (5.72 mg AAE/g). FTIR data confirmed physical interactions among components; XRD revealed a semi-crystalline structure; and SEM showed a porous surface with visible cracks. Application of strawberries reduced weight loss and decay by 22.88 and 1.33% (day 4 at 3–5 °C) and 46.1 and 2.67% (day 12 at 28–31 °C). These results demonstrate the potential of potato peel starch and Sungkai leaf extract as an eco-friendly preservation solution.
Co-Authors Afdhal Muttaqin Aldini, Tasya Ardiani, Ajeng Putri Ashikin, Nor Boneta, Fella Krisna Deliza, Deliza Efendi Efendi Farrah Aprilina Fuji Astuti Febria Hamidah, Nofi Hamzar Suyani Hermansyah Aziz Ilham, Muhammad Samudra Indrawati - Indrawati Indrawati Indri Ticel Leone Irma Yanti Siregar Irmanida Batubara Mai Efdi Mairawita, Mairawita Mega Ulfaningsih Mildawati Mildawati Narwen Narwen Nasution, Ainun ndrawati - Novita Lucia RAMADANI, MUTIA Refilda Refilda Richi Silvianti Rosman, Widuri Safni Safni Solfiyeni Solfiyeni Syafwan, Mahdivan Umiati Loekman Umiati Loekman Yani Kasuma Putri Zilfa Zilfa Zulfi, Zulfi