Evaluation of compressional-puffing pretreatment for antioxidant phenolic compounds extraction from Pinus morrisonicola
Date Issued
2016
Date
2016
Author(s)
Chiang, Pai-Shih
Abstract
Pinus morrisonicola has been reported bio-benefit and contains high amount of antioxidant bioactive compounds. This study is aimed to increase the extraction yield and efficiency of the antioxidant phenolic compounds from Pinus morrisonicola. A simple, environmentally friendly and reactant-saving compressional-puffing process is applied to the pretreatment of the extraction process. Scanning electron microscopy and mercury intrusion porosimetry are used to characterize the morphological changes. Also, high-performance liquid chromatography and Fourier transform infrared spectroscopy are used to analyze and characterize phenolic compounds of the pine needles extracts. The results show that compressional-puffing leads to a considerable destruction of the cell walls of the pine needles’ with the appearance of numerous nanopores. By fitting the data to a second-order kinetic extraction model has led to a 9 fold increase of the initial extraction rate. By HPLC and FTIR, the major components of the pine needles extracts are identified as catechin. The suitable extraction conditions for catechin are aqueous ethanol as solvent in a range of 25 to 50 % (v/v) while the extraction temperature is maintained less than 70 ºC in order to prevent the decomposition and ionization of phenolic compounds. Besides the utilization of the pretreatment, the optimum extraction conditions for the phenolic compounds from pine needles are determined by using response surface methodology with a central-composite design. The effects of ethanol concentration, extraction temperature and liquid-solid ratio on the extraction yield (total flavonoids content and total phenolic content) and antioxidant activity (DPPH scavenging activity, FRAP and ABTS scavenging activity) are investigated. A quadratic model afforded a superior ‘fit’ of the experimental data with R2 > 0.98 and p value < 0.01. The optimum conditions to maximise the extraction yields and antioxidant activity of the pine needles extracts are: 36.1 % (v/v) of ethanol, 70 ºC and 50 mL/g of liquid-solid ratio. Under these conditions the extraction of pine needles, pretreated by compressional-puffing, is conducted and the result show a 5 fold increase in extraction yield of phenolic compounds and a 3 fold increase in antioxidant activity. In addition, the pine needles extracts are also compared with commercial enzyme products and show competitiveness in both total phenolic content and antioxidant activity.
Subjects
Pinus morrisonicola
Phenolic compounds extraction
Antioxidant activity
Compressional-puffing pretreatment
catechin
Response surface methodology
Type
thesis