Comparison of nutritional composition, anti[1]inflammatory and antioxidative activities between the raw and boiled raphanus sativus subsp. longipinnatus roots

• Main Author: Ong, Yin Jie
• Format: Final Year Project / Dissertation / Thesis
• Published: 2022
• Subjects: Q Science (General); QD Chemistry
• Online Access: http://eprints.utar.edu.my/4912/1/fyp_BM_2022_OYJ.pdf; http://eprints.utar.edu.my/4912/
• Institution: Universiti Tunku Abdul Rahman

Raphanus sativus subsp. longipinnatus (daikon radish) is widely consumed by Asians and claimed to have anti-inflammatory and antioxidant activities. However, this statement was not proven scientifically. Many studies mainly focused on red radishes (Raphanus sativus L.), with limited research done on daikon radish. This study analysed the nutritional composition, anti-inflammatory, and antioxidant activities of the raw and boiled daikon radish roots. The nutritional composition including moisture, ash, crude protein, crude fibre, and crude fat were analysed according to the AOAC guidelines, while the mineral content was determined using Flame Atomic Absorption Spectrometry (FAAS). In this research, 80% methanol was used to obtain sample extracts for bioactivities analysis. The protein denaturation assay (PDA) was used to examine the anti-inflammatory capabilities; while DPPH radical scavenging assay, total phenolic content (TPC) and ferric-reducing antioxidant power (FRAP) assays were utilised to analyse the antioxidant activities. Student’s T-test was used to statistically compare the raw and boiled results. The moisture (96.64 ± 0.05% FW), ash (25.10 ± 1.10% DW) and crude fibre (16.41 ± 1.60% DW) contents were found higher in the boiled daikon radish roots. The raw daikon radish roots have a higher crude protein content at 12.69 ± 0.44% DW. No significant differences in crude fat were found between both samples. Calcium and magnesium remained to be two of the most abundant minerals in the raw and boiled samples. Besides, the boiled daikon radish root extracts exhibited lower half-maximal inhibitory concentration (IC50) values in PDA (664.79 ± 27.25 g/mL) and DPPH (1.59 ± 0.09 mg/mL) assays, giving a higher anti-inflammatory and antioxidant activity. Although the raw daikon radish had higher TPC (6.36 ± 1.52 g GAE/g sample), no significant differences were found between the raw and boiled sample extracts in the FRAP. Therefore, the boiled daikon radish roots were noted to give higher nutritional value.