Indonesia is a tropical country that is gifted with a high number of natural-resources types. The biodiversity of plants growing in Indonesia is about more than 25,000 types. Most of the plants were reported to show potential bioactive (Wulansari and Chairul, 2011). One of the most common bioactive found in the plants was its antioxidant characteristics (Ekiert and Szopa, 2020).
Antioxidant activity plays an important role to help indicate the potential of other biological activities. Antioxidant helps to reduce oxidative stress such as inflammation, aging, and carcinogenesis (Vergara et al., 2021).
Dragon fruit, which is native to Mexico and cultivated in Indonesia, is rich in antioxidants. According to Park et al (2008), polyphenols which can be found mostly in the pulps and peels of dragon fruit contribute to antioxidant activity. Apart from that, betalains also add a high amount of antioxidant activities (Esquivel et al., 2007).
Other than dragon fruit, dates are also high in antioxidants. Phenolic compounds in dates play essential roles in donating hydrogen atoms, reducing agent, metal chelators, and a singlet oxygen quencher (Al-Jasass et al., 2015).
In Saudi Arabia, a report showed that antioxidant activity of ethanol extract of dates have IC50 for about 84.92 ppm (Al-Mamary et al., 2014).
Kefir is a fermented dairy product composed of lactic acid and alcohol. It tastes a bit sour, thick, and refreshing. Therefore, kefir is often mixed in health drink.
In several developing countries, kefir has been widely consumed as a beverage and medication to treat various illnesses. This fermented dairy product provides phenolic, causing a high amount of antioxidant activity (Kesenkas et al., 2011).
Those three food materials are rich in antioxidant. However, there has not been any report on the bioactivity of the mixture of the materials. Mixing the materials into a healthy drink would become a consumable source of antioxidants. The researcher expected that the mixture of antioxidant compound activity could synergize one another, producing a high source of antioxidant (Crespo et al., 2019). The three materials would be mixed into juice in different ratio compositions. In the end, it was found that the precise compositions of healthy drinks are high-antioxidant.
The materials were collected from Surabaya and Banjarmasin. The research was conducted in Banjarmasin where the dragon fruit was collected during the harvest moon (October to April). The dates were collected from Saudi Arabia.
The next step was to find variations of mixture. The ratio of mixtures were shown in the following table 1. All the variations were stored in the fridge with 16° C for 3-4 days.
The measurement of antioxidant activities conducted using the DPPH method. The sample, which was a mixture of the three materials and standard, were prepared in the methanol. The measurement was conducted using the DPPH standard curve. The absorption was compared to the standard solution absorbance.
The IC50 value showed the ability to scavenge free radicals (DPP). The IC50 value was calculated from the absorbance of blank, standard, and samples. All measurements of samples (A-T) were done in three replications.
The IC50 value which was obtained from each solution (A-T) was further statistically analyzed to find out the normality using Kolmogorov-Sminorv. After that, another tes was conducted using analysis of variance (ANOVA) F-Table with α=0.05 using SPSS software. It is concluded that the mixture with the highest antioxidant activity was the sample O (kefir : dates = 10 : 5) reaching 32,1 mg/dl. For the future study, it is advised to analyze the several types of dragon fruit which may indicate different antioxidant activities.
Author: Amalia
Journal title: PRELIMINARY STUDY OF ANTIOXIDANT ACTIVITY OF DRAGONFRUIT, DATES AND KEFIR MIXTURES
Journal link: https://e-journal.unair.ac.id/JVHS/article/view/24401
