Antioxidant activity of different plant parts extracts of Dracaena umbratica Ridl

Medicinal plants contain phytochemicals which show various significant biological and pharmacological activities. In this study, the hexane, dichloromethane and methanol extracts from different parts (leaves, rhizomes and roots) of a local medicinal plant, Dracena umbratica, Ridl (Agavaceae) were evaluated for antioxidative activity using ferric thiocyanate (FTC) method and also DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay. The results showed that all the extracts exhibited weak radical scavenging activity and differ significantly from the standard antioxidants which are vitamin C and butylated hydroxytoluene (BHT). However results from the ferric thiocyanate (FTC) method showed that all the extracts except that of hexane and dichloromethane extracts of the rhizome of this plant possess high antioxidative property which was comparable to the standard reference, BHT. The antioxidative activity of these extracts did not differ significantly (P<0.5) from BHT. These results suggest that this plant species may have low content of radical scavenging compounds but can still be developed as potential antioxidant

Kesan suhu pengekstrakan akueus terhadap ciri fizikokimia dan antioksidan gam bendi (Abelmoschus esculentus)

Penyelidikan ini dijalankan untuk menilai ciri fizikokimia gam bendi yang diekstrak pada suhu 25, 40, 60 dan 80 ℃. Ekstrak gam bendi kemudiannya dianalisis bagi penentuan pH, warna, kapasiti pengikat air, reologi dan kandungan fenol jumlah (TPC). Aktiviti antioksidan iaitu pemerangkapan radikal bebas 2,2-diferil-1-pikrihidrazil (DPPH) serta kuasa antioksidan penurunan ferik (FRAP) turut dijalankan. Hasil berat kering gam bendi menunjukkan tiada perbezaan signifikan (p>0.05) pada suhu pengekstrakan 25 ℃ dan 40 ℃. pH ekstrak gam bendi adalah hampir neutral (pH 6.69-6.75) pada suhu pengekstrakan 25 ℃ hingga 80 ℃, mempunyai warna yang cerah dan kuning kehijauan. Kapasiti pengikat air gam bendi yang diekstrak pada 25 ℃ dan 40 ℃ didapati lebih tinggi secara signifikan (p0.05). Kesimpulannya, peningkatan suhu pengekstrakan dapat meningkatkan hasil esktrak tetapi memberi kesan pengurangan kapasiti pengikat air serta kelikatan ketara ekstrak gam yang terhasil. Oleh itu, adalah penting untuk mengenal pasti objektif akhir penggunaan gam bendi bagi membolehkannya diekstrak menggunakan suhu yang paling sesuai dengan potensi penggunaannya

Cellulose powder from Piper nigrum L. agro-industrial waste: effect of preparation condition on chemical structure and thermal degradation

White pepper is generally produced via water retting process to decorticate the pericarp of green pepper. The decorticated pericarp is considered as an agro-industrial waste and environmental pollutant as many farmers still discard the waste into the rivers. These wastes majorly contain cellulose, hemicellulose, pectin, and other organic compound. Cellulose was obtained from alkaline treatment (4 wt. % sodium hydroxides, NaOH) followed by bleaching process. This study reports the effect of soaking cycle in bleaching treatment on the chemical structure and thermal degradation of cellulose. The cellulose obtained from pepper (Piper nigrum L.) pericarp waste were characterised by colour analysis, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Increased number of bleaching cycles produced a whiter colour and high thermal stability of cellulose powder. The whiteness index (WI) for high bleaching cycle sample was found significantly high (p<0.05) with the value of 77.00 ± 1.10. Thermal analysis indicates a derivative thermogravimetric analysis (DTG) peak at 332 °C. The FTIR spectrum proven that the condition of bleaching treatment changes the absorption intensity at bands 1732, 1540, and 1460 cm-1 which due to the loss of hemicellulose and lignin. The use of pepper pericarp waste that is usually discarded may provide a sustainable alternative for the production of cellulose

Assessment of natural cellulosic powder from pepper pericarp waste (Piper nigrum L.) after alkalization and bleaching treatment : effect of alkali concentration and treatment cycle

Pepper (Piper nigrum L.) pericarp is an agriculture waste in the production of white pepper. It is underutilised agro-industrial waste which could be a promising natural source of cellulose. Hence, finding an optimum way to remove the non cellulose components without degrading the cellulose structure is essential. In this work, the effects of alkaline concentration (4, 5, and 6% NaOH) and number of soaking cycle (3 & 4 cycles) on the characteristics of cellulose from pepper pericarp were investigated. The obtained cellulose powder was characterized for its yield, α-cellulose content, particle size, zeta potential, morphology, whiteness index, crystallinity degree and thermal stability. The white powder cellulose after 4th cycle treatment with 4% NaOH appeared to have the highest yield (23.63%), α-cellulose (65.97%), crystallinity structure (51%) and better thermal stability at 334 °C. FTIR spectrum at band around 1732 cm-1 indicates a partial removal of non-cellulosic material at all alkalization condition due to the presence of remaining lignin and hemicellulose. These may contribute to formation of negative surface charge on all cellulose samples which may potentially enhance the functionality of the material as emulsifier. Based on two-way ANOVA test, concentration and cycle of alkaline treatment significantly (p<0.05) influenced the yield, particle size and zeta potential, meanwhile α-cellulose significantly influence by NaOH concentration only (p<0.05). The findings showed that manipulating the synthesis condition of cellulose powder influenced its properties which could be further used in various applications

Kesan penambahan Gam Bendi (Abelmoschus esculentus) pada emulsi minyak dalam air

Kajian ini dilakukan untuk menentukan kesan penambahan gam bendi (Abelmoschus esculentus) ke atas emulsi minyak dalam air. Gam bendi diperolehi melalui pengekstrakan akueus dan dikering bekukan sebelum dilarutkan semula mengikut kepekatan yang dikehendaki. Minyak kelapa sawit (20%) digunakan bagi membentuk emulsi minyak dalam air dengan penambahan isolat protein wei (1%) sebagai pengemulsi. Sebanyak 0.0, 0.5, 1.0, 2.0 dan 3.0% ditambah ke dalam formulasi emulsi yang dihasilkan. Analisis fizikokimia yang digunakan sebagai respons ialah ujian kelikatan, kadar pengkriman dan kadar penyingkiran protein permukaan. Emulsi kawalan yang distabilkan menggunakan protein wei (kawalan) adalah stabil sehingga hari ke-5 tanpa pengkriman secara signifikan (p>0.05). Walau bagaimanapun, pengkriman berlaku pada hari ke 7 dan bertambah secara signifikan (p<0.05) pada hari ke 10. Penambahan gam bendi pada kepekatan tinggi iaitu 2.0 dan 3.0% didapati membantu mengekalkan kestabilan emulsi minyak dalam air. Sampel kawalan mempunyai kelikatan yang paling rendah. Penambahan gam bendi dilihat menyebabkan kelikatan emulsi minyak dalam air yang dihasilkan juga bertambah mengikut kepekatan gam bendi yang digunakan. Terdapat peningkatan penyahjerapan protein daripada permukaan antara minyak dan air yang diakibatkan oleh penambahan gam bendi. Fenomena ini kelihatan lebih cenderung berlaku pada kepekatan gam bendi yang lebih rendah (0.5 dan 1.0%). Oleh yang demikian, gam bendi berpotensi digunakan di dalam produk berasaskan emulsi untuk meningkatkan kelikatan dan kestabilan terhadap pengkriman