Article Per Year (5 Year)
p-Index From 2019 - 2024
0.61
P-Index
This Author published in this journals
All Journal Jurnal Riset Kimia
-, Yefrida
Department Of Chemistry, Faculty Of Mathematics And Natural Sciences, Universitas Andalas
Chemistry

Published : 4 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 4 Documents
Search

 1 
VALIDASI METODA FRAP MODIFIKASI PADA PENENTUAN KANDUNGAN ANTIOKSIDAN TOTAL DALAM SAMPEL MANGGA DAN RAMBUTAN Yefrida -; Nor Ashikin; Nor Ashikin; Refilda -; Refilda -
Jurnal Riset Kimia Vol. 8 No. 2 (2015): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v8i2.236

Abstract

Validation of modified FRAP method to determine total antioxidant content in mango and rambutan sample have been done. Total antioxidan content in sampel is presented as Gallic Acid Equivalent (GAE). Modified FRAP method using FeCl3asoxidizing agent and ortho-phenantroline as complexan, which produce complex compounds of [Fe (C12H8N2)3]+2 sorrel coloured. Validation parameters are obtained in this research are r = 0.999, R2 = 0.998, LoD 3.13 x 10-6 M and LoQ 1.04 x 10-5 M. While RSD and recovery in the sample mango and rambutan were 1.15%, 1.34% and 96.31%, 97.72%, respectively. Based on the value of the validation parameters, it can be concluded that this method can be used for determination of total antioxidant content in the mango and rambutan samples.
Validasi Metode MPM untuk Penentuan Kandungan Antioksidan dalam Sampel Herbal serta Perbandingannya dengan Metode PM, FRAP dan DPPH Yefrida Yefrida; Hamzar Suyani; Hermansyah Aziz; Mai Efdi
Jurnal Riset Kimia Vol. 11 No. 1 (2020): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v11i1.342

Abstract

The Modified Phenanthroline Method (MPM) has been validated for determination of antioxidant content in herb samples. Validation was done using Relative Standard Deviation (RSD) and percentage of recovery. The RSD and percentage of recovery for herb samples are 3.13% and 98.6%, respectively. Based on these values, MPM method is valid for determining antioxidant content in herb samples. T test shows no significant differences of antioxidant content using any of these methods, MPM, PM, FRAP or DPPH, at a 95% confidence level. MPM method shows a very strong correlation with PM and FRAP method.  While with DPPH and TPC shows is strong.
Penentuan Kandungan Antioksidan Total pada Infusa Selada Hijau (Lactuca sativa L.) Hidroponik dan Konvensional secara Spektrofotometri dengan Modified Phenantroline Method (MPM) Yefrida Yefrida; Refilda Refilda; Nofi Hamidah; Widuri Rosman
Jurnal Riset Kimia Vol. 13 No. 1 (2022): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v13i1.492

Abstract

Green lettuce is a vegetable that is widely consumed in Indonesia. These vegetables come from conventional and hydroponic farming. This study aims to compare the antioxidant content of these two types of vegetables. This vegetable is extracted by the infundation method. The extract obtained was determined for its antioxidant content by the MPM method. This method was validated by using parameter LoD, LoQ, linearity, precision and accuracy. The results showed that this method was valid for determining the total antioxidant content in conventional and hydroponic green lettuce samples. The total antioxidant content in conventional and hydroponic green lettuce samples was 2.68 ± 0.65 mg aa/g FW and 1.67 ± 0.40 mg AA/g FW, respectively. T test stated that the antioxidant content of the two samples was significantly different.
Teknik Edible Coating dengan menggunakan Campuran Gel Lidah Buaya dan Ekstrak Daun Psidium guajava L. untuk Mempertahankan Sifat Fisikokimia Buah Jambu Biji Refilda Refilda; Riga Habib Ngestu; Emil Salim; Yefrida
Jurnal Riset Kimia Vol. 13 No. 2 (2022): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v13i2.501

Abstract

The synthetic chemicals is a common substance used to extend the shelf life of postharvest fruit. But it can have health impact. The use of edible coatings from natural ingredients has begun to be developed. Modification of aloe vera gel by guava leaf extract as the edible coating to increase guava fruit shelf life has not been reported yet. Guava fruit coated by several compositions of aloe vera gel and guava leaf extract have been carried out. Observations on physichochemical in fruit on the days 0, 3, 6, 9, 12 and 15 were evaluated. The best quality found on guava fruit treated with the compotition of aloe vera gel:ethanol guava leaf extract: CMC:glycerol (90: 5:0.25: 0.5) on the day 15. It had a weight loss of 9.88%, a spoilage of 3.33%, the decrease of water content 11.61%, titratable acidity 0.5%, total antioxidant 1.08 mg AA/g FW, total phenolic 0.51 mg GAE/g FW, and increase of total dissolved solids 3.01 oBrix. This result was significantly better than the uncoated fruit. It can be concluded that guava leaf extract can be used to maintain the physicochemical properties during storage.
Co-Authors Hamzar Suyani Hermansyah Aziz Mai Efdi Nofi Hamidah Nor Ashikin Nor Ashikin Refilda Refilda Riga Habib Ngestu Salim, Emil Widuri Rosman