RESULTS: Defatted kenaf seed powder yielded four DF fractions: alkali-soluble hemicellulose (146.4 g kg-1 ), calcium-bound pectin (10.3 g kg-1 ) and acid-soluble pectin (25.4 g kg-1 ) made up the soluble fibre fraction, whereas cellulose (202.2 g kg-1 ) comprised the insoluble fraction. All fractions were evaluated for their physicochemical properties. The DF fractions contained glucose, mannose, xylose and arabinose, and a small amount of uronic acid (1.2-2.7 g kg-1 ). The isolated pectin fractions had a low degree of esterification (14-30%). All the isolated DF fractions had high average molecular weights ranging from 0.3 to 4.3 × 106 g mol-1 . X-ray diffractogram analysis revealed that the fractions consisted mainly of an amorphous structure with a relative crystallinity ranging from 31.6% to 44.1%. The Fourier-transform infrared spectroscopy spectrum of kenaf seed and its DF fractions showed typical absorption of polysaccharides, with the presence of hydroxyl, carboxyl, acetyl and methyl groups. Scanning electron microscopy analysis demonstrated that the raw material with the rigid structure resulted in soluble and insoluble DF fractions with more fragile and fibrous appearances, respectively. The soluble DF demonstrated greater flowability and compressibility than the insoluble fractions.
CONCLUSION: These findings provide novel information on the DF fractions of kenaf seeds, which could be used as a potential new DF for the food industry. © 2023 Society of Chemical Industry.
RESULTS: All aqueous enzymatic extraction (AEE)-based methods generally resulted in oil with better oxidative properties and higher tocopherol retention than the use of solvent. Prior to AEE, boiling pre-treatment deactivated the hydrolytic enzymes and preserved the oil's quality. In contrast, high-pressure processing (HPP) pre-treatment accelerated hydrolytic reaction and resulted in an increase in free fatty acids after 140 days at all temperatures. No significant changes were detected in the oils' iodine values and fatty acid composition. The tocopherol content decreased significantly at both 13 and 25 °C after 60 days in the oil from SE method, and after 120 days in oils from AEE-based methods.
CONCLUSION: These findings are significant in highlighting the extraction methods resulting in crude MO kernel oil with greatest oxidative stability in the storage conditions tested. Subsequently, the suitable storage condition of the oil prior to refining can be determined. Further studies are recommended in determining the suitable refining processes and parameters for the MO kernel oil prior to application in variety food products. © 2019 Society of Chemical Industry.
METHODS: 5'-phosphodiesterase (5'-PDE) enzyme was characterized from adzuki beans, in which the optimum pH and temperature were determined. In addition, the stability of 5'-PDE was assessed at different pH and temperature. The effects of cations and EDTA were evaluated to characterize the 5'-PDE enzymes further.
RESULTS: The alkaline 5'-phosphodiesterase has an optimum pH of 8.5. This enzyme is also thermostable, with an optimum temperature of 80°C. The stability in terms of temperature and pH was also determined, and was found to be stable in the pH range of 7.0-8.5. This enzyme was found to retain more than 80% of its activity for 4 days at 60 and 65°C. In addition, the effects of 14 different metal ions, 4 types of detergents and ethylenediaminetetraacetic acid (EDTA) on 5'-PDE were studied. Ca2+, K+, Mg2+ and Li+ activated 5'-PDE while Na+, Zn2+, Ni+, Hg+, Cu2+, Pb2+, Fe2+, Al3+, Ba2+ and Co2+ were inhibitory. EDTA, Triton X-100 and sodium dodecyl sulfate (SDS) were strong inhibitors of 5'-PDE, while Tween 80 and Tween 20 were slightly inhibitory. The effects of cations and EDTA suggest that 5'-PDE from adzuki beans is a metalloenzyme.
CONCLUSIONS: Although 5'-PDE from adzuki beans has a high temperature optimum of 80°C, the enzyme is more stable at 60°C, and different cations affected the activity of the enzyme differently.