Elucidation of thermal degradation of Labisia pumila’s polyphenols /
Afiqah Yeop,
Elucidation of thermal degradation of Labisia pumila’s polyphenols / Afiqah Yeop - xviii, 226 pages : illustrations (some color) ; 30 cm. + 1 CD ROM
College of Engineering
Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang – 2021
Includes bibliographical references
This work deals with Labisia pumila which is one of the herbal chosen for research and development by the Malaysian National Key Economic Areas (NKEA) under Entry Point Projects 1 (EPP1). L. pumila (Kacip Fatimah) contains many useful polyphenols often used for traditional treatment of menstrual irregularities, pre-, and post-partum complications. Processing stage of L. pumila, for example extraction and drying is often performed at elevated temperature above 60°C. Different extraction method involves various amount of auxiliary energy, i.e., maceration extraction (ME) 0.1-0.6 W/mL, microwave assisted extraction (MAE) 5-30 W/mL and ultrasonic assisted extraction (UAE) 0.7-2 W/mL. Therefore, one of the aims of this work is to study the effect of auxiliary energy on the yield of Labisia pumila from ME, MAE and UAE. These three extraction methods were analysed based on the extraction auxiliary energy via liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) using a principle component analysis method to compare both differences and similarities of bioactive compounds profile. The UAE and ME produced a similar polyphenols profile due to their broadly similar amount of auxiliary energy, while MAE provided a different distribution due to high auxiliary energy. Bioactive compounds such as flavonoids, vitamins and proteins are known to undergo thermal degradation when subjected to high temperatures for a long period of time and these degraded substances may be either detrimental health effect. L. pumila polyphenols degradation kinetics is not understood, and therefore this is the focus of this work. This work aims to determine the thermal degradation kinetics of polyphenols from L. pumila using Arrhenius type kinetics by measuring the polyphenols degradation at temperature 60, 90 and 120°C and time up to 90 min using LC-QTOF-MS. The most stable compound among the targeted polyphenols marker was protocatechuic acid followed by epigallocatechin, rutin and gallic acid in the authentic standard study. Furthermore, in L. pumila’s extract protocatechuic acid was less sensitive to heat followed by gallic acid, rutin and epigallocatechin. The different pattern of compounds stability was due to the existence of several polyphenols in the extract that affected the degradation or formation of the targeted compounds. The LC-QTOF-MS was used for molecules identification of main and degraded compounds. At low collision energy, the mass spectrometry (MS) analysis provided the exact mass spectra of parent compound while the MS fragmentation pattern was determined under high collision energy. The fragmented compound detected with a good match namely malic acid, fumaric acid, protocatechuic aldehyde, catechin, pyrogallol and catechol. In addition, the degradation mitigation during product processing was developed via microencapsulation aiming to improve product quality. The greatest retention of gallic acid (95.18%), protocatechuic acid (91.19%), epigallocatechin (86.00%) and rutin (95.87%) was achieved by using 10% gum arabic in whey protein isolate. The binding energy for carbon, oxygen and nitrogen was elucidated using molecular imaging of thin sample via x-ray photoelectron spectroscopy (XPS), whereas the surface morphology of spray dried powder was evaluated with scanning electron microscope (SEM). The release mechanism of polyphenols from the microcapsule was better represented by the Hixson-Crowell kinetics model suggesting the erosion dominated mechanism.
THE0008596(Local)
College of Engineering--Dissertations
Universities and colleges--Dissertations
Theses
Elucidation of thermal degradation of Labisia pumila’s polyphenols / Afiqah Yeop - xviii, 226 pages : illustrations (some color) ; 30 cm. + 1 CD ROM
College of Engineering
Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang – 2021
Includes bibliographical references
This work deals with Labisia pumila which is one of the herbal chosen for research and development by the Malaysian National Key Economic Areas (NKEA) under Entry Point Projects 1 (EPP1). L. pumila (Kacip Fatimah) contains many useful polyphenols often used for traditional treatment of menstrual irregularities, pre-, and post-partum complications. Processing stage of L. pumila, for example extraction and drying is often performed at elevated temperature above 60°C. Different extraction method involves various amount of auxiliary energy, i.e., maceration extraction (ME) 0.1-0.6 W/mL, microwave assisted extraction (MAE) 5-30 W/mL and ultrasonic assisted extraction (UAE) 0.7-2 W/mL. Therefore, one of the aims of this work is to study the effect of auxiliary energy on the yield of Labisia pumila from ME, MAE and UAE. These three extraction methods were analysed based on the extraction auxiliary energy via liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) using a principle component analysis method to compare both differences and similarities of bioactive compounds profile. The UAE and ME produced a similar polyphenols profile due to their broadly similar amount of auxiliary energy, while MAE provided a different distribution due to high auxiliary energy. Bioactive compounds such as flavonoids, vitamins and proteins are known to undergo thermal degradation when subjected to high temperatures for a long period of time and these degraded substances may be either detrimental health effect. L. pumila polyphenols degradation kinetics is not understood, and therefore this is the focus of this work. This work aims to determine the thermal degradation kinetics of polyphenols from L. pumila using Arrhenius type kinetics by measuring the polyphenols degradation at temperature 60, 90 and 120°C and time up to 90 min using LC-QTOF-MS. The most stable compound among the targeted polyphenols marker was protocatechuic acid followed by epigallocatechin, rutin and gallic acid in the authentic standard study. Furthermore, in L. pumila’s extract protocatechuic acid was less sensitive to heat followed by gallic acid, rutin and epigallocatechin. The different pattern of compounds stability was due to the existence of several polyphenols in the extract that affected the degradation or formation of the targeted compounds. The LC-QTOF-MS was used for molecules identification of main and degraded compounds. At low collision energy, the mass spectrometry (MS) analysis provided the exact mass spectra of parent compound while the MS fragmentation pattern was determined under high collision energy. The fragmented compound detected with a good match namely malic acid, fumaric acid, protocatechuic aldehyde, catechin, pyrogallol and catechol. In addition, the degradation mitigation during product processing was developed via microencapsulation aiming to improve product quality. The greatest retention of gallic acid (95.18%), protocatechuic acid (91.19%), epigallocatechin (86.00%) and rutin (95.87%) was achieved by using 10% gum arabic in whey protein isolate. The binding energy for carbon, oxygen and nitrogen was elucidated using molecular imaging of thin sample via x-ray photoelectron spectroscopy (XPS), whereas the surface morphology of spray dried powder was evaluated with scanning electron microscope (SEM). The release mechanism of polyphenols from the microcapsule was better represented by the Hixson-Crowell kinetics model suggesting the erosion dominated mechanism.
THE0008596(Local)
College of Engineering--Dissertations
Universities and colleges--Dissertations
Theses