pH Of Extraction Medium Research Articles

Study of Influential Parameters of the Caffeine Extraction from Spent Coffee Grounds: From Brewing Coffee Method to the Waste Treatment Conditions

This article aims to study the interest of spent coffee grounds (SCG) valorization through caffeine recovery. In an original way, this study takes into account all the parameters such as (i) the brewing coffee methods (household, coffee shops, etc.); (ii) the storage conditions, in particular the drying step; (iii) the solid/liquid extraction parameters such as the nature of solvent, the temperature, the extraction time and the solid/liquid ratio; and (iv) the liquid/liquid purification parameters such as the nature, the volume and the pH of extraction medium. Results have shown that spent coffee grounds from coffee-shops obtained by percolation contain a higher amount of caffeine than spent coffee grounds from households obtained from spent pods or filters. A drying treatment is not required when extraction is performed under one week after the spent coffee grounds collection with 96.4% of not degraded caffeine. Solid/liquid extraction performed with 25 mL.g−1 SCG of hydroalcoholic solvent (water/EtOH, v/v 60/40) at 60 °C during 15 min have given a caffeine yield up to 4.67 mg.g−1 SCG. When using ethyl acetate, 93.4% of the caffeine has been selectively recovered by liquid/liquid extraction. Finally, the extraction of caffeine for the valorization of spent coffee grounds is a promising and easy way, which fits with an already important and well established market.

Effect of pH on the flaxseed (Linum usitatissimum L. seed) mucilage extraction process

Water-soluble mucilage extracted from flaxseed has excellent hydrocolloid potential in gel formation; moreover, it can become a product of high technological value in the food, pharmaceutical and cosmetic industries because it has high viscosity in aqueous solution. The aim of the current study is to investigate the effect of extraction medium pH on extraction yield and soluble fiber content. In addition, the purification step effect was evaluated through Fourier transform infrared spectroscopy (FTIR). Extractions were carried out at 3 different pH values (3.81, 6.75 and 9.69) for 13.25 h at 45 oC. The highest yield was recorded at pH 6.75; the highest soluble fiber content was found at pH 3.81. It was possible seeing that the extraction of flaxseed macromolecules in basic medium (pH 9.69) presented the best quality in comparison to other extractions. The purification step based on precipitation with ethanol did not fully remove impurities from the samples.

A simple downstream processing protocol for the recovery of lactic acid from the fermentation broth

Lactic acid is one of the essential platform chemicals, and despite the availability of a range of downstream processes, its effective recovery is still elusive. A phase partitioning process using n-butanol and a chaotropic salt ammonium sulphate was developed to recover lactic acid from the fermentation broth of Lactobacillus pentosus SKL-18. During the optimization of various process parameters, the extraction medium's pH was found to be critical, with 2.5 being the best. The optimized process resulted in a lactic acid yield of 86% and found it to be 93% pure. The purity and characteristics of lactic acid were confirmed by FTIR and NMR spectra. This solvent-based extraction procedure is an economical and straightforward downstream process for purifying lactic acid produced from agro- and bakery-residues. The pure lactic acid can further be used for enzymatic synthesis of high value-added product PLA, a biodegradable and biocompatible plastics.

Coupling effects of preheating time and extraction medium pH on red radish anthocyanin yield, glucosinolate degradation and off-odour removal

Summary In this study, the effect of combined preheating time (2, 5, and 10 min) and extraction medium pH (2.5, 3.5, and 4.5) on total monomeric anthocyanin yield, and removal of off-odour in red radish anthocyanins were evaluated. The tentative anthocyanin identification showed twelve pelargonidin anthocyanins, and only nine were identified in samples preheated for 10 min. Sample preheated for 10 min and extracted at pH 4.5 showed lower the anthocyanin yield (98.02 mg/100 g, FW), lighter colour and higher percentage polymeric colour compared with that preheated for 2 min and extracted at pH 2.5. However, prolonged preheating time (10 min) significantly reduced myrosinase enzyme activity by 73%. Additionally, results showed that preheating time and extraction medium pH have negative and significant effect on the total monomeric anthocyanin yield, while they showed positive and negative significant effect on the total glucosinolate degradation. Furthermore, the sensory evaluation results revealed no significant difference in radish odour for samples preheated for 2 and 5 min followed by anthocyanin extraction in pH 2.5 medium. It might therefore be concluded that the combination of moderated preheating treatment time (≤5 min) and lower extraction medium pH could be effective to reduce the off-odour characteristics and maintaining high yield and stable red radish pigment.

Optimization of the Glycyrrhizic Acid Extraction from Licorice by Response Surface Methodology

This study aims to extract Glycyrrhizic Acid (GA) from Glycyrrhiza glabra L. (licorice) using a novel, high efficiency, and low-cost extraction method. Water was chosen as the proper solvent for the extraction process to eliminate the requirement of harmful and toxic solvents, prepare an environmentally friendly process, and reduce the costs. The effect of different process variables (extraction time, feed to solvent ratio, pH of extraction medium, and temperature) on the extraction, yield was investigated experimentally and statistical analysis using the RSM method was performed to analyze the effect of variables and obtain a proper model correlating the yield of extraction to variables. The obtained model was found successful in fitting the experimental results. It was found that all the four variables affect the yield of extraction significantly, and only the interaction between pH and extraction time was found important in increasing the GA% in the precipitate. The highest yield was achieved experimentally 54.9%, for the case with the extraction time of 17 h, feed to solvent ratio of 10 g/ml, pH of 10, and temperature of 60oC.On the other hand, the optimum condition obtained by the model was found at extraction time of 10.12 h, feed to solvent ratio of 10.71 g/ml, pH of 9.8, and temperature of 119.7oC.

Study of total dry matter and protein extraction from canola meal as affected by the pH, salt addition and use of zeta-potential/turbidimetry analysis to optimize the extraction conditions

Total dry matter and proteins were differentially and preferentially extracted from canola meal (CM) under different conditions. The effect of the extraction medium pH, CM concentration and salt concentrations were found to have different influences on the extractability of total dry matter and proteins from CM. The pH of the extracting medium had the most significant effect. The maximal total dry matter (42.8±1.18%) extractability was obtained with 5% CM at pH 12 without salt addition, whereas the maximal for total protein (58.12±1.47%) was obtained with 15% CM under the same conditions. The minimal extractability for the dry matter (26.63±0.67%) was obtained with 5% CM at pH 10 without salt added and the minimal protein extractability was observed in a 10% CM at pH 10, in 0.01 NaCl. Turbidity and ζ-potential measurements indicated that pH 5 was the optimum condition for the highest protein extraction yield. SDS–PAGE analysis showed that salt addition contributes to higher solubility of canola proteins specifically cruciferin fraction, although it reduces napin extraction.

بهینه سازی استخراج اینولین از غده‌ی سیب زمینی ترشی به کمک روش سطح پاسخ (RSM)

Inulin is widely used in functional foods throughout the world for its health-promoting and technological properties. Helianthus tuberosus is cultivated widely in the northern part of Iran. Helianthus tuberosus can be a valuable source of Inulin. To optimize conventional extraction of Inulin, various combinations of time, temperature, and solvent: solid ratio, were used. In this research, a series of statistically designed studies were performed to investigate the effect of each of the independent variables (temperature and pH of extraction medium, extraction time, and solvent: solid ratio). The following variables: solvent: solid ratio (5-12 v/w), temperature (40-90°C) and time (5-40 min) were studied. The central composite design (CCD) and response surface methodology (RSM) were employed as experimental design and statistical analysis. Based on canonical analysis, the optimal conditions for maximizing Inulin extraction yield (42.2%) were 76.64°C for 23.90 min and solvent: solid ratios of 12:1 (v/w). Keywords: Inulin, Extraction, Helianthus tuberosus, Response surface methodology

Optimization of Processing Parameters for the Preparation of Flounder Frame Protein Product

Flounder frame was used as a raw material for the preparation of protein product. Processing parameters were evaluated using both fresh and frozen ground frames. The results indicate the following optima: (1) pH of extraction medium, ii; (2) extraction time, 60 min; (3) volume to weight ratio, 10: 1; (4) extraction temperature, 23°C. Isoelectric precipitation was conducted at pH 5 using KCI or H3PO4. Results indicate that NaOH was more effective than Ca(OH)2 in solubilizing frame protein at pH 11. Ground frozen flounder frames gave a 10% decrease in protein extractability when compared to fresh frames using NaOH as the extractant and a 22% decrease when Ca(OH)2 was employed as the extractant. Approximately 70% of the protein is recovered using the NaOH-HCI system.

Release Rate of Drugs from Ethyl Cellulose Coated Granules Containing Caffeine and Salicylic Acid

Fluidized bed coating with ethyl cellulose., polyethylene glycol mixtures has been utilized for prolongation of drug release from granules containing salicylic acid and caffeine as model drugs. Drug release from the coated granules followed first order kinetics.Particle size of the active material, granule composition and extraction medium pH did not affect the rate and kinetics of drug release. Increase in coat thickness decreased the release rate whereas elevation of the ratio of polyethylene glycol to ethyl cellulose enhanced the release rate to a degree related to the polyethylene glycol concentration. The permeability constants of salicylic acid and caffeine for the ethyl cellulose-polyethylene glycol coatings were of a similar order to those measured previously using solutions of the drugs with planar barrier films.

Influence of extraction medium pH on the protein content of some legume starches

SummaryStarches of lentil, garbanzo and field bean were isolated according to a detailed separational scheme at several pHs in the range of 5.5 to 9.5 and nitrogen determinations made on the purified samples. Nitrogen determinations and protein solubility profiles were also determined on the legume flours in order to facilitate a comparison of the data obtained for the starches. the relationship between protein solubility and starch protein content is discussed. the protein content of garbanzo starch decreased from a value of 0.51% at pH 5.5 to a value of 0.13% at pH 9.5. For field bean starch the protein content was 0.55% at pH 5.5 and 0.18% at pH 9.5. In the case of lentil starch the protein content decreased from 0.42% at pH 5.5 to 0.25% at pH 7.5 with very little change up to a pH of 9.5. It was found that extraction medium pH has no effect upon the yield of starch.