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| 090 | _aKK .Y46 2022 r Thesis | ||
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_aLing, Yeong Yi _eauthor. |
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_aEffect of auxiliary energy on polyphenols extraction from senna alata (L.) ROXB / _cYeong Yi Ling |
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_aPahang : _bUMP, _c2022 |
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| 264 | 4 | _c© 2022 | |
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_axxiii, 232 pages: _bIllustration ; _c30 cm.+ _e1 CD ROM |
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| 500 | _aCollege of Engineering | ||
| 502 | _aThesis (Doctor of Philosophy) -- Universiti Malaysia Pahang – 2022 | ||
| 504 | _aIncludes bibliographical reference | ||
| 520 | 3 | _aSenna alata (L.) Roxb is a herbal that contains many medically useful polyphenols such as flavonoids and anthraquinones (i.e. kaempferol 3-gentiobioside (K3G), kaempferol ( KA), aloe emodin (AE), rhein (RH) and emodin (EM)). These polyphenols perform various functions such as antioxidant, antimicrobial, anticancer, hypoglycaemic, hypolipidemic and act as laxative. The active components must be extracted before it can be routinely used for phytomedicinal purpose. Besides that, there is no previous work on polyphenols extraction from S. alata using microwave assisted extraction (MAE). The effect of the auxiliary energy on the polyphenols from S. alata with maceration (ME), ultrasonic assisted extraction (UAE) and MAE using principal component analysis (PCA) was rarely compared. Moreover, degradation kinetic parameters of active components and thermally-induced synthesized compound from heat treatment in S. alata leaves have not been discovered so far. Hence, this study aims to close the aforementioned knowledge gap. In this research, UAE and MAE were studied to compare with a reference method, conventional ME. Apart from that, the microstructure of S. alata leaves were treated by ME, UAE and MAE and examined using a scanning electron microscope. Other than that, PCA was performed on MS data using UPLC-QTOF-MS. PCA was conducted to study the effect of auxiliary energies on polyphenols extraction using different extraction methods. Besides that, thermal stability of polyphenols is crucial for the formulation of new food products and food processes such as boiling, hot air drying and frying. The reaction order is determined to estimate the activation energy and kinetic parameters such as degradation rate and half-life of active component degradation during heat treatment. The degradation products from thermal processing of polyphenols were identified using UPLC-PDA and UPLC-QTOF-MS. It was found that the extraction yield of active components using MAE was about 18.73 % to 84.12 % significantly higher than ME. Besides that, MAE is 60x faster compared to ME. Apart from that, the optimum processing conditions of microwave-assisted simultaneous extraction of major active components (K3G, KA and AE) are 90.5% ethanol and microwave power of 18.6 W/mL using CCD with a desirability of 0.82. MAE has the highest extraction rate, which used 10 W/mL of auxiliary energy compared to UAE (0.8 W/mL) and ME (0.05 W/mL). The glandular trichomes were ruptured and decreased by 98.6 % compared to freshly dried leaf after treated by MAE. In PCA, a clear discrimination of cluster among the three extraction methods was shown in score plot. There are 14 major active components contributed to the difference of cluster. Apart from that, high auxiliary energy (MAE) caused degradation of thermolabile components and synthesis of by-products. Degradation of other active components will lead to the formation of AE and RH in MAE. The results showed degradation of K3G, KA and synthesis of AE and RH in S. alata followed the zero-order kinetics model with R2 > 0.9881. KA showed the highest degradation rate constant at 180 °C, indicating a most thermolabile compound while K3G is the most stable compound with the lowest degradation constant at 180 °C in S. alata. In this work, AE, RH, AS and DA are thermally-induced synthesized from other active components in S. alata. | |
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