@phdthesis{digilib49969,
           month = {December},
           title = {PENGARUH PENAMBAHAN EKSTRAK DAUN BIDARA (ZIZIPHUS SPINA-CHRISTIL.) TERHADAP BILANGAN PEROKSIDA MINYAK JELANTAH},
          school = {UIN SUNAN KALIJAGA YOGYAKARTA},
          author = {NIM.: 16630008 Ida Kurniawati},
            year = {2021},
            note = {Pembimbing: Dr. Susy Yunita Prabawati, M.Si.},
        keywords = {Minyak, Oksidasi, Bilangan Peroksida, Antioksidan, Ekstrak Daun
Bidara.},
             url = {https://digilib.uin-suka.ac.id/id/eprint/49969/},
        abstract = {Used cooking oil is cooking oil that has been damaged, one of which is
caused by exposure to oxygen. Exposure to oxygen in the oil triggers oxidation so
that the oil smells rancid and decreases the quality of the oil. Furthermore, the
decrease in the quality of the oil was indicated by an increase in the peroxide
value of the oil. One of the ways to reduce the peroxide value in the oil is by
adding natural antioxidant. One of the natural ingredients tested for antioxidant
content is bidara leaf extract. Bidara leaf extract is produced from extraction
using methanol by the maceration method. Bidara leaf extract has bioactive
compounds including flavonoids and saponins that function as antioxidants.
Antioxidant activity in bidara leaf extract was tested by DPPH method (Dhiphenyl
picryl hydrazil) with a comparison solution of BHT (Butylated hydroxytoluene) at
a wavelength of 516.5 nm. The antioxidant activity of bidara leaf extract was
lower than BHT with IC50 values of 9.53 g/mL and 3.7 g/mL, respectively. The
antioxidant activity of bidara leaf extract and its effect on peroxide levels were
tested by mixing the extract into used cooking oil. The average peroxide value of
used cooking oil after the addition of bidara leaf extract was 8.6402 O2/Kg. This
value is lower than the average used cooking oil without the addition of bidara
leaf extract of 8.9366 O2/Kg. Finally, statistical testing with the t-test revealed a
significant effect on the administration of bidara leaf extract on the peroxide
value of used cooking oil with a p-value {\ensuremath{<}}0.05.}
}