Mmol Ascorbic Acid Research Articles

The Value of Using Green Extraction Techniques to Enhance Polyphenol Content and Antioxidant Activity in Nasturtium officinale Leaves

Increasing research is being directed toward the production of value-added products using plant extracts that are super-fortified with antioxidants. In this study, the extraction parameters for bioactive compounds (such as polyphenols) from Nasturtium officinale leaves and their antioxidant properties were optimized using response surface methodology. The optimization procedure examined the effects of the extraction temperature, time, and solvent composition on conventional magnetic stirring (ST). In addition, the impacts of two green techniques—pulsed electric field (PEF) and ultrasound (US)—were evaluated individually and in combination to assess their potential to enhance the extraction of the compounds. According to our findings, under the proposed extraction conditions (a combination of PEF, US, and ST as a extraction technique, 50% ethanolic solvent, for 30 min at 80 °C). N. officinale leaf extract proved to be an excellent source of bioactive compounds, with extracts containing rosmarinic acid (3.42 mg/g dried weight (dw)), chlorogenic acid (3.13 mg/g dw), total polyphenol content (28.82 mg of gallic acid equivalents (GAE)/g dw), and strong antioxidant properties. The FRAP method measured 57.15 μmol ascorbic acid equivalents (AAE)/g dw, while the DPPH radical scavenging activity method measured 47.55 μmol AAE/g dw. This study was carried out to evaluate and improve the concentration of bioactive compounds in N. officinale leaf extract, resulting in a product with multiple applications across the food, cosmetic, and pharmaceutical industries.

Response Surface Methodology-Aided Optimization of Bioactive Compound Extraction from Apple Peels Through Pulsed Electric Field Pretreatment and Ultrasonication

Apple by-products (i.e., peels) are often thrown away, yet they are highly nutritious and provide numerous advantages as they contain a variety of nutrients such as vitamins, minerals, and antioxidants. Apple peels also comprise a high level of antioxidants, particularly polyphenols and flavonoids. This research aimed to determine the most efficacious extraction techniques and parameters to accomplish maximum bioactive compounds recovery from apple peels. Several extractions were conducted, including stirring, ultrasonication, and pulsed electric field-assisted extractions. Response surface methodology and several factors such as temperature, extraction duration, and solvent composition were considered to have a major impact on the isolation of bioactive compounds. The findings indicated that the most practical and efficient approach was to combine the pulsed electric field process with ultrasonication and stirring at 80 °C for 30 min, while 75% aqueous ethanol comprised the optimal solvent concentration, demonstrating the critical role of the solvent in optimizing extraction efficiency. The optimal conditions were obtained through response surface methodology with a statistical significance of p < 0.05. The extract exhibited a total polyphenolic content (TPC) of 17.23 mg gallic acid equivalents (GAE) per g of dry weight (dw), an ascorbic acid content (AAC) of 3.99 mg/g dw, and antioxidant activity of 130.87 μmol ascorbic acid equivalents (AAE)/g dw, as determined by FRAP and 95.38 μmol AAE/g dw from the DPPH assay. The measured antioxidant activity highlighted the significant potential of apple peels as a cost-effective source of exceptionally potent extracts.

Exploring Conventional and Green Extraction Methods for Enhancing the Polyphenol Yield and Antioxidant Activity of Hyssopus officinalis Extracts.

Hyssopus officinalis L. (HO) is, as one of the most prevalently utilized plants, used in traditional medicine to cure various diseases as well as the in food and cosmetic industries. Moreover, HO is a rich source of polyphenols with potent antioxidant properties. However, the studies on the extraction of such compounds from HO are scanty and sparse. This study aims to optimize the extraction of polyphenols and maximize the antioxidant activity in HO extracts. A comprehensive experimental design was employed, encompassing varied extraction parameters to determine the most effective ones. Alongside conventional stirring (ST), two green approaches, the ultrasonic treatment (US) and the pulsed electric field (PEF), were explored, either alone or in combination. The extracted polyphenolic compounds were identified with a high-performance liquid chromatography-diode array detector (HPLC-DAD). According to the results, the employment of ST along with an ethanolic solvent at 80 °C for 150 min seems beneficial in maximizing the extraction of polyphenols from HO, resulting in extracts with enhanced antioxidant activity. The total polyphenol was noted at 70.65 ± 2.76 mg gallic acid equivalents (GAE)/g dry weight (dw) using the aforementioned techniques, and the antioxidant activity was noted as 582.23 ± 16.88 μmol ascorbic acid equivalents (AAE)/g dw (with FRAP method) and 343.75 ± 15.61 μmol AAE/g dw (with the DPPH method). The as-prepared extracts can be utilized in the food and cosmetics industries to bestow or enhance the antioxidant properties of commercial products.

Optimization of Four Different Rosemary Extraction Techniques Using Plackett-Burman Design and Comparison of Their Antioxidant Compounds.

Rosemary has many medicinal and therapeutic properties and therefore it is important to study how to maximize the recovery of its bioactive compounds. In the present study, four different extraction techniques were used, namely stirring extraction (STE), pulsed electric field-assisted extraction (PEF), ultrasound probe-assisted extraction (UPAE), and ultrasound bath-assisted extraction (UBAE). First, some primary experiments were carried out in order to optimize each technique individually through the Plackett-Burman design. Then, each technique was applied under optimal conditions and the results were compared with each other. The optimal total polyphenol content (TPC) of STE is ~19 mg gallic acid equivalents per gram of dry weight (dw), while the antioxidant activity of the extract is 162 μmol ascorbic acid equivalents (AAEs) per gram of dw via FRAP and ~110 μmol AAE per gram of dw via DPPH. As for PEF, the optimal TPC is ~12 mg GAE/g dw, and the FRAP and DPPH values are ~102 and ~70 μmol AAE per gram of dw, respectively. When it comes to UPAE, the optimal TPC is ~16 mg GAE/g dw and the antioxidant capacity of the extract is ~128 μmol AAE/g dw through FRAP and ~98 μmol AAE/g dw through DPPH. UBAE optimal extract yielded ~17 mg GAE/g dw TPC, ~146 μmol AAE/g dw for FRAP, and ~143 μmol AAE/g dw for DPPH. The highest flavonoid content (~6.5 mg rutin equivalent/g dw) and DPPH (~143 μmol ascorbic acid equivalent/g dw) is obtained through UBAE. UPAE has been shown to be more efficient in recovering ascorbic acid (~20 mg/g dw). Additionally, the chlorophyll-to-carotenoid ratios of UPAE and UBAE were 2.98 and 2.96, respectively, indicating that the extracts had a generally positive impact on health. Considering the environmental impact of each extraction technique but also which antioxidant factor needs to be maximized, the most suitable extraction technique will be chosen.

Enhancing the Nutritional Profile of Crataegus monogyna Fruits by Optimizing the Extraction Conditions

Crataegus monogyna (CM) fruits are highly regarded for their rich nutritional content, boasting elevated levels of various beneficial secondary metabolites like total polyphenols, including anthocyanins, and ample amounts of ascorbic acid and antioxidant activity. Despite the acknowledged benefits of CM fruits, researchers have directed more attention toward its leaves and flowers. Consequently, the current research attempts to optimize extraction techniques for CM fruit using a multifaceted approach involving varied durations, temperatures, and concentrations of ethanol solvent to isolate the diverse range of bioactive components present effectively. High-performance liquid chromatography coupled with a diode array detector (HPLC-DAD) is employed for the identification and quantification of polyphenolic compounds. According to the results, by following the optimum extraction parameters (50% ethanolic solvent, 50 °C extraction temperature, and 60 min extraction time), the total polyphenol content can be increased up to 410%, reaching 55.59 mg gallic acid equivalents/g. Using 50% ethanolic solvent, 80 °C extraction temperature, and extraction time of 90 min, the total anthocyanin content can be enhanced by more than 560%, reaching a quantity of 51.83 μg cyanidin equivalents/g. Moreover, the antioxidant activity of CM fruit extracts can reach 415.95 μmol ascorbic acid equivalents (AAE)/g dw (by FRAP method), using 50% ethanolic solvent, 50 °C extraction temperature, and 60 min extraction time, and 270.26 μmol AAE/g dw (by DPPH method) and 1053.28 mg/100 g dw ascorbic acid content, using 50% ethanolic solvent, 80 °C extraction temperature, and 90 min extraction time. This comprehensive study seeks to augment the already substantial content of bioactive compounds found in CM, resulting in an extract with promising applications across the pharmaceutical, food, and cosmetics industries.

Extraction of Antioxidants from Brown Macroalgae Fucus spiralis.

In this study, different extraction methods and conditions were used for the extraction of antioxidants from brown macroalgae Fucus spiralis. The extraction methodologies used were ultrasound-assisted extraction (ultrasonic bath and ultrasonic probe), extraction with a vortex, extraction with an Ultra-Turrax® homogenizer, and high-pressure-assisted extraction. The extracts were analyzed for their total phenolic content (TPC) and their antioxidant activity, and evaluated through the 2,2-difenil-1-picrilhidrazil (DPPH) free radical scavenging method and ferric reducing antioxidant power (FRAP) assay. Ultrasonic probe-assisted extraction yielded the highest values of TPC (94.78-474.16 mg gallic acid equivalents/g extract). Regarding the antioxidant activity, vortex-assisted extraction gave the best DPPH results (IC50 1.89-16 µg/mL), while the highest FRAP results were obtained using the Ultra-Turrax® homogenizer (502.16-1188.81 μmol ascorbic acid equivalents/g extract). For each extraction method, response surface methodology was used to analyze the influence of the experimental conditions "extraction time" (t), "biomass/solvent ratio" (R), "solvent" (S, water % in water/ethanol mixture), and "pressure" (P) on TPC, DPPH, and FRAP of the F. spiralis extracts. In general, higher TPC content and higher antioxidant capacity (lower IC50 and higher FRAP) were obtained with higher R, t, and P, and lower S (higher ethanol %). The model regarding the combined effects of independent variables t, R, and S on the FRAP response values for vortex-assisted extractions best fitted the experimental data (R2 0.957), with optimal extraction conditions of t = 300 s, R = 50 g, and S = 25%.

Bioactive Compound Extraction of Hemp (Cannabis sativa L.) Leaves through Response Surface Methodology Optimization

Hemp, commonly known as Cannabis sativa L., is a medicinal plant species of the Cannabaceae family. For the efficient extraction of C. sativa leaves using the conventional stirring process with water as the solvent, three crucial extraction parameters (i.e., extraction duration, liquid–solid ratio, and temperature) were investigated through the response surface methodology (RSM). The concentrations of the extracted bioactive compounds (polyphenols, ascorbic acid, and carotenoids) showed significant variations in the RSM design points, suggesting the importance of finding the optimal extraction conditions in which liquid–solid ratio and extraction temperature were found to have the highest impact. Further analysis was conducted on the optimal extract employing several assays to determine their polyphenol content, total carotenoid content, color evaluation, anti-inflammatory activity, and antioxidant capacity through FRAP, DPPH, and H2O2 assays. A low extraction time (30 min) at 50 °C and a high liquid–solid ratio (50:1) were required for the highest possible yield of polyphenols. The total polyphenol content was determined to be 9.76 mg gallic acid equivalents/g under optimum conditions, with pelargonin being the most abundant polyphenol (1.51 mg/g) in C. sativa extracts. Ascorbic acid was measured at 282.23 μg/g and total carotenoids at 356.98 μg/g. Correlation analyses revealed that anti-inflammatory activity was negatively correlated with specific polyphenols. As determined by DPPH (27.43 μmol ascorbic acid equivalents (AAE)/g), FRAP (49.79 μmol AAE/g), and H2O2 (230.95 μmol AAE/g) assays, the optimized aqueous extract showed a high antioxidant capacity. Furthermore, it demonstrated considerable anti-inflammatory activity at 17.89%, with the potential to increase to 75.12% under particular extraction conditions. Given the high added-value of the aqueous extracts, the results of this study highlight the potential utility of C. sativa leaves as a source of health-improving antioxidant compounds in the pharmaceutical and food industries.

Exploring Varied (Green) Extraction Methods to Optimize Galia Melon Peel Antioxidant Potential

Cucumis melo L. (C. melo), commonly known as the melon, is a widely cultivated tropical fruit associated with nutritional benefits and bioactive properties. With global production reaching 40 million tons annually, the fruit processing industry generates significant waste, primarily peels, totaling 8 to 20 million tons yearly. These organic by-products are rich in bioactive compounds such as antioxidants, offering health benefits such as a reduced risk of cancer and cardiovascular diseases, as well as of diabetes and neurogenerative diseases, offering an opportunity for sustainable utilization. C. melo by-products have demonstrated various health benefits, including anti-inflammatory, analgesic, and antioxidant properties, attributed mainly to polyphenols. Recognizing the potential of melon waste, this study systematically explored different extraction methods, including stirring (ST), ultrasound (US), and pulsed electric field (PEF) methods, while considering factors such as extraction time, temperature, and solvent composition. The primary goal was to identify the most effective extraction procedures and optimal conditions for maximizing the yield of total polyphenols and antioxidant capacity (using the FRAP and DPPH methods) from C. melo peel by-products. According to the results, the optimum conditions include ST as the extraction method, an ethanolic solvent with a strength of 50%, a 150 min extraction duration, and an 80 °C extraction temperature. The maximum values of total polyphenols that can be observed are 3.75 mg gallic acid equivalents (GAE)/g of dry weight (dw) and 25.77 μmol ascorbic acid equivalents (AAE)/g dw and 34.44 μmol AAE/g dw from FRAP and DPPH antioxidant assays, respectively. The polyphenols identified were the following: gallic acid, neochlorogenic acid, catechin, chlorogenic acid, epicatechin, and kaempferol. By securing the maximum isolation of bioactive content and antioxidant activity, the research will contribute to sustainable waste management by reducing waste and developing value-added products.

Optimization of Pressurized Liquid Extraction (PLE) Parameters for Extraction of Bioactive Compounds from Moringa oleifera Leaves and Bioactivity Assessment.

Moringa oleifera leaves are rich sources of bioactive compounds with potential health benefits, including antioxidants and anti-inflammatory agents. Pressurized liquid extraction (PLE) stands out as a promising technique for effectively extracting valuable compounds from natural sources. In this study, we aimed to optimize PLE parameters, such as temperature, extraction duration, and pressure, to maximize bioactive compound (polyphenols, flavonoids, and ascorbic acid) yield from M. oleifera leaves and evaluate their antioxidant and anti-inflammatory activities. According to the outcomes of this research, the maximum achieved total polyphenol content was 24.10 mg gallic acid equivalents (GAE)/g of dry weight (dw), and the total flavonoid content was increased up to 19.89 mg rutin equivalents (RtE)/g dw. Moreover, after HPLC-DAD analysis, neochlorogenic and chlorogenic acids, catechin and epicatechin, rutin, and narirutin were identified and quantified. As far as the optimum ascorbic acid content is concerned, it was found to be 4.77 mg/g dw. The antioxidant activity was evaluated by three different methods: ferric reducing antioxidant power (FRAP), the DPPH method, and the anti-hydrogen peroxide activity (AHPA) method, resulting in 124.29 μmol ascorbic acid equivalent (AAE)/g dw, 131.28 μmol AAE/g dw, and 229.38 μmol AAE/g dw values, respectively. Lastly, the albumin denaturation inhibition was found to be 37.54%. These findings underscore the potential of PLE as an efficient extraction method for preparing extracts from M. oleifera leaves with the maximum content of bioactive compounds.

Exploring the Antioxidant Properties of Citrus limon (Lemon) Peel Ultrasound Extract after the Cloud Point Extraction Method

Each year, a substantial amount of food is discarded around the globe. A significant portion of this waste consists of by-products derived from Citrus fruits such as lemons. The purpose of this research is to examine the polyphenol extraction and the antioxidant ability of lemon peel using cloud point extraction (CPE), a sustainable approach. CPE was conducted using three steps with a 20% w/v concentration of Span 20 as the surfactant, which has a critical micellar concentration of 6.13 × 10−5 mol/L. The pH was set at 7 and a salt concentration of 20% was maintained at 45 °C for 20 min. The subsequent outcomes of the analysis were obtained: total polyphenol content (TPC): 526.32 mg gallic acid equivalents per liter; total flavonoid content (TFC): 90.22 mg rutin equivalents per liter; FRAP, DPPH, and hydrogen peroxide assays: 2.40, 2.68 and 1.03 mmol ascorbic acid equivalents per liter, respectively, and 168.63 mg/L ascorbic acid content. The quantification of the polyphenolic compounds through High-Performance Liquid Chromatography showed that the most abundant compounds in the lemon peels are eriocitrin (159.43 mg/L) and hesperidin (135.21 mg/L). The results indicate that the proposed CPE technique is successful in extracting antioxidant compounds from lemon peels. The generated extracts have the potential to be exploited as dietary additives to enhance human health and can also be utilized for nutraceuticals or pharmaceutical purposes.

Antioxidant-Rich Extracts from Lemon Verbena (Aloysia citrodora L.) Leaves through Response Surface Methodology

A member of the Verbenaceae family, Aloysia citrodora, or lemon verbena, is a medicinal herb with antioxidant compounds. The aim of this study was to develop a green, optimized method for the bioactive compound (carotenoids, ascorbic acid, and polyphenols) extraction from lemon verbena leaves through response surface methodology (RSM). The bioactive compound recovery was shown to be significantly affected by the extraction technique (both with pulsed electric field and ultrasound-assisted extraction), along with an extraction solvent, based on partial least squares analysis. Consequently, the maximum polyphenol yield required a double-assisted extraction with a relatively low extraction duration (60 min) at a high temperature (80 °C), with a moderate-polarity extraction solvent (50% v/v ethanol). With the optimized method, the total polyphenol content (TPC) was measured at 175.03 mg gallic acid equivalents/g, whereas chromatographic analysis revealed that verbascoside was the most prevalent polyphenol (132.61 mg/g). The optimum extract provided a high antioxidant capacity through the measurements of FRAP (1462.17 μmol ascorbic acid equivalents (AAE)/g), DPPH (1108.91 μmol AAE/g), and H2O2 (1662.93 μmol AAE/g). Total carotenoids were measured at 499.61 μg/g, with ascorbic acid at 8.36 μg/g. Correlation analyses revealed a negative correlation of the latter compound with color coordinates. This study highlights the potential of lemon verbena leaves to be used in pharmaceutical and food industries.

Antioxidant Capacity in Two Different Cultivars of Ripe and Unripe Peaches Utilizing the Cloud-Point Extraction Method

In this study, the objective was to ascertain the optimal extraction method for the recovery of polyphenols from two peach cultivars, namely ‘Andross’ and ‘Everts’, at unripe and ripe stages. Two extraction techniques were explored: conventional extraction and cloud-point extraction (CPE), utilizing various solvents, including water, ethanol, 60% ethanol, and the surfactant Tween 80. Moreover, the conditions of CPE (such as pH, ionic strength, surfactant concentration, etc.) were optimized. To elucidate the antioxidant activity of the extracts, the total polyphenol content (TPC), the ferric-reducing antioxidant power (FRAP) assay, and the DPPH antiradical scavenging were measured. Our findings indicate that CPE is a superior method for polyphenol recovery. Unripe fruits had more antioxidants than ripe ones. Unripe ‘Andross’ fruit has a TPC of 1465.32 mg gallic acid equivalents per kilogram (mg GAE/kg). FRAP and DPPH levels were 7.33 and 5.12 mmol ascorbic acid equivalents (AAE/kg), respectively. With a TPC of 1714.53 mg GAE/kg, the unripe fruit from the ‘Everts’ cultivar has even more antioxidant capacity. Additionally, its FRAP and DPPH values were increased at 8.57 and 6.08 mmol AAE/kg, respectively. These findings underscore the efficacy of CPE as a preferred method for polyphenol extraction while also highlighting the enhanced antioxidant potential of unripe peaches, particularly in the ‘Everts’ cultivar.

Growth performance and secondary metabolite production of Adenostemma madurense using different fertilizers

Adenostemma madurense is one of the Asteraceae with many medical properties but has not been widely cultivated. This study aims to determine the different fertilizer doses that can produce the best growth, phenolic, flavonoid, terpenoid, and the 11α-OH KA (a diterpenoid found in A. madurense productivity), resulting in the high antioxidant capacity of A. madurense. A one-factor randomized block design was employed in five fertilizer doses, control/without fertilizer, 100 % cow manure (20 tons/ha), 100 % NPK (in the form of urea, SP-36, and KCl:135, 100, 135 kg/ha, respectively), a combination of 50 % cow manure + 50 % NPK, and a combination of 100 % cow manure + 100 % NPK. Fertilizers increase plant growth. Applying the combination of 100 % cow manure + 100 % NPK was the best fertilizer composition, which produced the highest plant height, leaf, and branch number. This fertilizer combination produced total phenolic, flavonoid productivity of 739.50 μmol Gallic Acid Equivalent/plant, 97.37 μmol Quercetin Equivalent/plant, not significantly different from applying 100 % NPK and the combination of 50 % cow manure + 50 % NPK, and terpenoid productivity of 77.51 mmol Nerol Equivalent/plant. The 11α-OH KA productivity and antioxidant capacity of this fertilizer is 18.00 mM 11α-OH KA/plant and 601.76 μmol Ascorbic Acid Equivalent/g dry sample, not significantly different from applying 100 % NPK. Applying 100 % cow manure + 100 % NPK may enhance the medicinal plant A. madurense’s efficacy, especially for antioxidants.

An Investigation into Crithmum maritimum L. Leaves as a Source of Antioxidant Polyphenols

Crithmum maritimum, commonly known as rock samphire, is a plant species with a long history of use in traditional medicine and cuisine, especially in the Mediterranean region. Despite its potential therapeutic and commercial applications, the number of studies on this plant species are scanty and sparse. The aim of this study was to optimize the solid–liquid extraction of bioactive compounds from C. maritimum leaves through response surface methodology (RSM) and to comprehensively analyze the resulting extracts. Experimental parameters including liquid-to-solid ratio, solvent composition, extraction time, and temperature were investigated. The results of the RSM revealed a notable variation in the values of the extracted bioactive compounds (polyphenols, carotenoids, and chlorophylls), indicating the selection of optimum extraction conditions. Partial least squares analysis showed that solvent composition and extraction temperature had a significant impact on the extraction of the bioactive compounds. Consequently, these conditions required a 145-min extraction at 80 °C, using a solvent consisting of 45% v/v ethanol, and a 40:1 liquid-to-solid ratio. The optimum extract was analyzed using a range of assays to determine their polyphenol content, their content in chlorophylls and carotenoids, and their antioxidant potential via FRAP and DPPH assays. The total polyphenol content was measured at 15.11 mg gallic acid equivalents (GAE)/g. High-performance liquid chromatography–diode array detector (HPLC-DAD) analysis revealed that chlorogenic acid was the most prevalent polyphenol (9.35 mg/g) in C. maritimum leaves. Kaempferol 3-glycoside (1.81 mg/g), naringin (1.24 mg/g), and hesperidin (0.79 mg/g) were some polyphenolic compounds that had also been quantified. Total carotenoids (0.32 μg/g) and total chlorophylls (0.62 μg/g) were also measured. Multivariate correlation analysis and principal component analysis revealed that total carotenoids and chlorophylls had a strong negative correlation with total polyphenol content. The reducing power (FRAP assay) of the optimized extract had a value of 85.52 μmol ascorbic acid equivalents (AAE)/g, whereas the antiradical activity (DPPH assay) was measured at 25.57 μmol AAE/g. Given the high quantity of polyphenols, these results highlight the potential use of C. maritimum as a source of bioactive compounds in the food and pharmaceutical industries.

Enhancing Antioxidant Properties of Prunus spinosa Fruit Extracts via Extraction Optimization

Prunus spinosa fruit, commonly known as blackthorn or sloe, possesses a wide range of health-promoting properties, including antioxidant and antibacterial activities. In this study, we investigated the effects of various extraction parameters, such as temperature, time, and solvent composition, on the extraction of bioactive compounds from P. spinosa fruit. Response surface methodology was employed to optimize these parameters and evaluate their impact on the antioxidant properties of the extracts. Furthermore, techniques such as ultrasound (US) and pulsed electric field (PEF) were applied, both individually and in combination, to explore their potential effects on the extraction process. The optimal extraction technique proved to be the combination of PEF and US, followed by stirring. The most suitable solvent was 75% ethanol, whereas the optimum extraction time and temperature were 30 min and 80 °C, respectively. Our findings revealed that under the optimum extraction parameters, a significant improvement in the extraction efficiency of bioactive compounds from P. spinosa fruit was achieved. More specifically, the optimal conditions, according to partial least squares (PLS) analysis, were a combination of all three extraction modes (PEF‒US‒ST), the shorter extraction time of the present study (30 min), and the corresponding higher temperature (80 °C). As expected, the presence of ethanol was considered necessary, even in an amount of 25%. The total polyphenol content was found to be 30.74 mg gallic acid equivalent (GAE)/g, the total flavonoids content 3.23 mg rutin equivalents (RtE)/g and the total anthocyanins 125.2 μg cyanidin-3-O-glucoside equivalents (CyE)/g. HPLC-DAD analysis showed that neochlorogenic acid was the polyphenol with the highest concentration (4.13 mg GAE/g) in P. spinosa fruit. The antioxidant activity of the optimized, according to PLS analysis, extract was evaluated and found to be 146.09 μmol ascorbic acid equivalent (AAE)/g determined by ferric reducing antioxidant power (FRAP) assay, and by the radical scavenging activity (DPPH) assay was 18.56 μmol AAE/g. Additionally, the ascorbic acid was determined to be 119.4 mg/100 g. Overall, this study contributes valuable insights into the extraction optimization process and the potential applications of P. spinosa fruit in the development of functional foods and pharmaceutical products.

Optimized Isolation Procedure for the Extraction of Bioactive Compounds from Spent Coffee Grounds

Due to the worldwide consumption of coffee, many tons of spent coffee grounds (SCGs) are discarded each year, as a by-product of coffee preparation. Not only their disposal is costly, but also it may cause the release of compounds that can endanger the environment. However, there are valuable chemical compounds that can be extracted from SCGs and used in the food industry. The aim of this study was to investigate the main parameters affecting the extraction of caffeine and polyphenols (i.e., chlorogenic acid, neochlorogenic acid, and caffeic acid) and to evaluate the antioxidant properties of the extracts. To this end, extraction solvent, temperature, time, and liquid-to-solid ratio were studied. A response surface methodology was used to optimize the extraction process. According to the results, the caffeine content of the optimum extract was found to be 6.14 mg/g in dry SCGs, the total polyphenol content was 19.85 mg gallic acid equivalents/g, while the ferric reducing antioxidant power and DPPH scavenging values were 136.69 μmoL ascorbic acid equivalents/g and 230.41 μmoL DPPH/g, respectively. The experimental values were in close agreement with the predicted ones, highlighting the potential of SCGs to be used for the isolation of bioactive compounds with the proposed extraction procedure.

Assessment of the Bioaccessibility of Elaeagnus angustifolia L. Flour and Its Use in Cracker Formulation

In this study, in vitro digestion of polyphenols of oleaster (Elaeagnus angustifolia L.) flour (OF) and the potential use of OF in cracker production were studied. The results showed that 21.90mg gallic acid equivalent (GAE)/g dry matter (DM) of total polyphenol (TP), 28.15mg rutin equivalent (RE)/g DM of total flavonoid (TF) and 7709.13mmol ascorbic acid equivalent (AAE)/100g DM of antioxidant capacity (AC) were found in OF. The bioaccessibility and content of the OF polyphenols and their AC during in vitro digestion varied depending on the digestion stage. The stability of the OF polyphenols was higher in gastric stage (41.92%) than intestinal one (34.01%). OF was used to replace flour in the cracker formulation at the levels of 5, 10 and 15% (w/w) and increased the TP contents and AC of the crackers compared to the sample without OF (control). The addition of OF to the cracker dough increased the bioaccessibility of the cracker polyphenols. After digestion, bioaccessibilities of enriched crackers (107.90-126.81%) were found higher than that of control sample (93.73%). However, as the level of OF in cracker increased, bioaccessibility of polyphenols decreased. The results generally indicated that oleaster has a good potential for the enrichment of foods.

Extraction of phenolic compounds from apple pomace, process modeling and antioxidant potential evaluation of extracts

Abstract Apple pomace, a byproduct of juice and cider production, is rich in phenolic compounds with antioxidant activity. This work studies the kinetics of solid–liquid extraction of phenolic compounds from apple pomace. Extraction kinetics were determined using a 50% water–ethanol solution and fitted to a phenomenological model. Equilibrium isotherms were also modeled. Effective diffusion coefficient values between 1.85x10−11 and 7.37x10−11 m2/s were found. External mass transfer resistance showed negligible results. The best yields (43.94%) were obtained at 60 °C with a solid–liquid ratio of 1:10 g/mL. Those conditions resulted in a total phenolic content of 9.95 mg gallic acid equivalents (GAE)/g apple pomace d.b., antioxidant FRAP activity of 5.07 mmol ascorbic acid equivalents (AAE)/100 g apple pomace d.b. and 3.74 mmol trolox equivalents (TRE)/100 g apple pomace d.b. based on a DPPH assay. Apple pomace extract efficiently stabilized sunflower oil and may represent a natural alternative to synthetic antioxidants.

OPTIMIZATION OF EXTRACTION OF POLYPHENOLS FROM CHESTNUT WASTE PRETREATED BY OHMIC HEATING USING BOX-BEHNKEN DESIGN

Chestnut processing produces a large amount of waste peels, which contain considerable polyphenols. The aim of this research was to optimize the extraction method for phenolic compounds from industrial chestnut peel pretreated by ohmic heating (OH) by using response surface methodology (RSM). Box-Behnken design (BBD) was used to investigate the effects of three independent variables; namely, extraction time, solid to solvent (S/S) ratio, and temperature, on total phenolic content (TPC) and antioxidant capacity (AC). All independent variables influenced the TPC and AC of the peel extracts. The optimum extraction conditions found were 22.02 min, 1/39.70 (w/v), and 60 °C for extraction time, S/S ratio, and extraction temperature, respectively, resulting in the highest TPC of 34.83 mg GAE/g dry matter (DM) and AC of 35621.38 mmol ascorbic acid equivalent (AEAC)/100 g DM by DPPH. This study showed that water was highly successful for the extraction of polyphenols from the pretreated chestnut peel.

Evaluation of the bioaccessibility of peanut skin polyphenols and their potential use for food enrichment

Polyphenols obtained from agricultural and industrial residues are also considered as remarkable sources of natural antioxidants to replace synthetic ingredients. In this study, the contents of total polyphenols (TP) and total flavonoids (TF), antioxidant capacity (AC) and in-vitro bioaccessibility of polyphenols (as gastric and intestinal stages) of the extract from peanut skin using water were investigated. Additionally, the potential use of peanut skin extract in noodle production was researched in order to add functionality to noodle, which is a widely consumed product. The results showed that 71.67 mg gallic acid equivalent (GAE)/g dry matter (DM) of TP, 123.11 mg rutin equivalent (RE)/g DM of TF and 66267.46 mmol ascorbic acid equivalent (AAE)/100g DM of AC were found in peanut skin. After the gastric and intestinal stages, the TP content and AC of the skin extract were found to be lower than the initial (before digestion) value. It was determined that polyphenols were more stable in gastric conditions than in the small intestine. The addition of the skin extract (0.4%) to the noodle dough increased the TP and AC of the final product compared to the noodle without the skin extract (control). It was observed that the stability of the polyphenols from the noodle sample was higher in gastric stage than intestinal one. The addition of peanut skin extract to the noodle dough increased the bioaccessibility of the polyphenols. Therefore, this study showed that peanut skin, as an important source of polyphenols, may be useful for food enrichment.