Optimisation of ultrasonic-assisted extraction of phenolic compounds, antioxidants, and anthocyanins from sugar beet molasses

Comparative evaluation of ultrasound-assisted extraction with other green extraction methods for sustainable recycling and processing of date palm bioresources and by-products: A review of recent research

The global food waste crisis has significantly contributed to climate change, water pollution, and land degradation. Date palm waste, including seeds, fronds, and fruit pulp residues, represents a valuable source of bioactive compounds with potential applications in food, pharmaceutical, and cosmetic industries. This study presents a comparative evaluation of ultrasound-assisted extraction and other novel extraction techniques, such as pressure-based extraction, pulsed electric fields, microwaves, and natural deep eutectic solvents, for recovering bioactive compounds from date palm waste. These methods were assessed for their efficiency and sustainability in extracting antioxidants and phenolic compounds, and other bioactives while minimizing the use of harmful solvents and high temperatures. Critical factors, such as extraction time, solvent type, temperature, and pressure were crucial indicators to achieve higher extraction efficiencies with lower environmental impacts compared to traditional methods. Additionally, combining these techniques may further optimize the extraction process. This study contributes to the development of sustainable strategies for valorizing date palm byproducts and promoting a circular economy in the food industry. By developing sustainable extraction methods that minimize environmental impacts, this research directly supports the United Nations' Sustainable Development Goals, particularly SDG 12 (Responsible Consumption and Production) and SDG 13 (Climate Action).

Extraction of phenolic acids and tetramethylpyrazine in Shanxi aged vinegar base on vortex-assisted liquid-liquid microextraction-hydrophobic deep eutectic solvent: COSMO-RS calculations and ANN-GA optimization

In this study, vortex-assisted liquid-liquid microextraction (VA-LLME) based on hydrophobic deep eutectic solvents (HDES) was used to efficiently and sustainably extract five phenolic acids and tetramethylpyrazine (TMP) from Shanxi aged vinegar (SAV). The VA-LLME technique was employed to investigate the extraction mechanism of HDES with the best extraction performance for the target compounds using a conductor-like screening model for real solvents (COSMO-RS). An artificial neural network combined with a genetic algorithm (ANN-GA) was developed to optimize the extraction conditions based on single-factor and response surface methodology, while also analyzing the interactive effects on the phenolic acids and TMP in the extracted solution during the extraction phase. The optimized conditions were determined, and the greenness of the procedure was evaluated using an analytical greenness metric, indicating that this technique can serve as a green alternative for the determination of phenolic acids and TMP in SAV.

Optimizing extraction conditions for isolation of antioxidant compounds from black rice bran using ultrasonic-assisted extraction and response surface methodology

Black rice bran (BRB), a valuable byproduct from the rice milling process, possesses numerous pharmacological activities, including antioxidant potential, but information regarding highly efficient extraction methods is scarce. To enhance the extraction efficiency, ultrasonic-assisted extraction coupled with Box-Behnken design (BBD) was used in this study to maximize the total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC), and antioxidant capacity of BRB extract. The BBD results showed that 57% ethanol at 50°C and pH 3.1 were best for TPC (136.2 mg GAE/g dry weight), TAC (2.3 mg cyanidin-3-O-glucoside equivalents/g dry weight), and TFC (38.6 mg quercetin equivalents/g dry weight). In vitro antioxidant capacities of BRB extract determined by 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays revealed free radical scavenging potentials with EC50 values of 67.62 and 1149 µg/mL, respectively. The cytotoxic effect of BRB extract on human skin HaCaT keratinocytes was determined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, which revealed no significant cytotoxicity and a significant increase in cell viability at a concentration of 500 µg/mL. Ultra-high performance liquid chromatography (UHPLC) analysis identified syringic acid, gallic acid, protocatechuic acid, vanillic acid, p-coumaric acid, and ferulic acid in BRB extract. This study provides the optimal conditions to extract antioxidant bioactive compounds from BRB and supports the use of BRB as a source of antioxidants. Due to BRB showing no significant cytotoxicity to human skin cells, it could potentially be further developed for topical applications.

RSM and ANN-Based Optimized Ultrasound-Assisted Extraction of Functional Components from Olive Fruit (cv Arbequina): Assessment of Antioxidant Attributes and GC-MS Metabolites Profiling

The current study devises an optimized ethanolic extraction for efficient recovery of high-value components from Pakistani olives (cv. Arbequina) using response surface methodology (RSM) and artificial neural networking (ANN). Four factors such as time, temperature, solvent concentration, and solute weight (g/100 mL) were evaluated as independent variables for determining the response (% yield). The results obtained under optimum extraction conditions such as duration (25 min), temperature (45 °C), solvent concentration (65 %; ethanol: water v/v), and solute (7.50 g/100 mL) offered bioactives extract yield of 40.96 % from Arbiquina olives. The analysis of variance (ANOVA) for the RSM model showed significant p-values and a correlation coefficient (R2) of 0.9960, confirming model's reliability. The results of ANN, which employed the multilayer perceptron design, were fairly in line with the findings of the experiments. The antioxidant characteristics and GC-MS metabolite profile of the obtained extracts were examined. Arbequina olive extract (AOE) demonstrated very good antioxidant ability in terms of total phenolic, total flavonoid contents, and DPPH radical scavenging. The GC-MS analysis of AOE confirmed the presence of several bioactives, including oleic acid (36.22 %), hydroxytyrosol (3.95 %), tyrosol (3.32 %), β-sitosterol (2.10 %), squalene (1.10 %), sinapic acid (0.67 %), α-tocopherol (0.66 %), vanillic acid (0.56 %), 3,5-di-tert-butylcatechol (0.31 %), and quercetin (0.21 %). The suggested optimized extraction method can be employed to efficiently extract a wide variety of high-value components from olives with potential for nutraceutical applications.

Green recovery of phenolic compounds from almond hull waste using ultrasound-assisted extraction: phenolics characterization and antimicrobial investigation

This research aims to maximize the extraction of phenolic compounds (PCs) from almond hull waste (AHW) using an ultrasound-assisted extraction (UAE) method, detect the PCs, and investigate the antimicrobial activity of the extracts against pathogens and interactions with a probiotic bacterium. The impact of various parameters including sonication amplitude, solvent/AHW ratio (mL/g), and extraction time on the total phenolic content (TPC) was investigated and the optimized extraction conditions were determined. The AHW extracts' minimum bacterial concentration (MBC) and minimum inhibitory concentration (MIC) against Staphylococcus aureus, Escherichia coli, and Lactobacillus plantarum were assessed. In optimal UAE conditions total PCs of 47.37 ± 0.24 mg gallic acid equivalent (GAE)/g dry weight (DW) were extracted. The HPLC analysis revealed that the flavonoid rutin, as well as p-coumaric acid and rosmarinic acid, were only seen in the extracts obtained by UAE. Furthermore, p-coumaric acid emerged as the most prevalent PC in the UAE extract. Antimicrobial activity analysis showed that UAE extracts exhibited higher effects in inhibiting the growth of E. coli, S. aureus, and L. plantarum. The use of UAE treatment resulted in the extraction of a diverse range of PCs with increased antioxidant capacity and antimicrobial activity.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05969-3.

Investigation and characterization of changes in potato peels by thermochemical acidic pre-treatment for extraction of various compounds

Potato peel waste (PPW) is an underutilized substrate which is produced in huge amounts by food processing industries. Using PPW a feedstock for production of useful compounds can overcome the problem of waste management as well as cost-effective. In present study, potential of PPW was investigated using chemical and thermochemical treatment processes. Three independent variables i.e., PPW concentration, dilute sulphuric acid concentration and liberation time were selected to optimize the production of fermentable sugars (TS and RS) and phenolic compounds (TP). These three process variables were selected in the range of 5-15 g w/v substrate, 0.8-1.2 v/v acid conc. and 4-6 h. Whole treatment process was optimized by using box-behnken design (BBD) of response surface methodology (RSM). Highest yield of total and reducing sugars and total phenolic compounds obtained after chemical treatment was 188.00, 144.42 and 43.68 mg/gds, respectively. The maximum yield of fermentable sugars attained by acid plus steam treatment were 720.00 and 660.62 mg/gds of TS and RS, respectively w.r.t 5% substrate conc. in 0.8% acid with residence time of 6 h. Results recorded that acid assisted autoclaved treatment could be an effective process for PPW deconstruction. Characterization of substrate before and after treatment was checked by SEM and FTIR. Spectras and micrographs confirmed the topographical variations in treated substrate. The present study was aimed to utilize biowaste and to determine cost-effective conditions for degradation of PWW into value added compounds.

Chitosan/teff flour active films incorporated with citric acid and beetroot leaf extract: Physicochemical properties and mathematical modeling of phenolic release

Active compounds are integrated into food packaging films to enhance their food protection capabilities. Understanding the release of these components in films, particularly in crosslinking scenarios, is crucial. This study aimed to mathematically model the release of phenolic compounds from chitosan/teff flour films to understand how active compounds gradually release. Moreover, it was aimed to study the effects of incorporation of beetroot leaf extract and citric acid crosslinking. The collective observations, encompassing increased density and thermal stability, alongside concurrent reductions in moisture content, water solubility, water vapor permeability and swelling index following citric acid addition, strongly suggested the presence of crosslinking. Applying Fick's law and the finite element method revealed a substantial influence of the crosslinking agent on diffusion coefficients. The model exhibited strong agreement with experimental data, as reflected in low root mean square error values ranging from 3.02 to 8.50 mmol/m3 for films. Furthermore, the influence of citric acid crosslinking on the release of TPC was evident, as indicated by a decrease in average diffusion coefficient values from 3.499 × 10-13 m2 s-1 to 1.770 × 10-13 m2 s-1 with the formula with 1.5 % citric acid and 0.5 % beetroot leaf extract. This showcases the impact of various parameters on controlled release in food packaging.

Dried Beetroots: Optimization of the Osmotic Dehydration Process and Storage Stability

In this study, beetroots were osmotically dehydrated in sugar beet molasses. The input parameters of the drying process were varied: temperature (20 °C, 40 °C, and 60 °C), time (1 h, 3 h, and 5 h), and concentration of sugar beet molasses (40%, 60%, and 80%). Basic quality indicators were determined for the dried beetroot samples: dry matter content, water loss, solid gain, mineral and betaine content, and phenols and flavonoids, as well as antioxidant potential. After optimizing the results, favorable drying parameters were selected: temperature 60 °C, molasses concentration 70%, and processing time 5 h. According to the optimal drying conditions, the beetroots were dried and stored at 4 °C for 28 days. Half of the dried samples were coated with an edible biopolymer coating based on Camelina sativa oilcake, while the other half of the samples remained uncoated. The sustainability study aimed to confirm the effects of the biopolymer coating on the quality and sustainability of the osmotically dried beetroots.

Effect of storage on bioactivity of an Algerian spice "paprika": optimization of phenolic extraction and study of antioxidant and antibacterial activities

The effect of different storage methods (ambient temperature (A), refrigeration at 4 °C (R) and freezing at - 18 °C (F)), on the phytochemistry of an Algerian spice (paprika powder), was assessed. The optimized extract was obtained under the optimum conditions of ultrasound-assisted extraction (UAE) using response surface methodology (RSM) coupled with a Box-Behnken Design (BBD). This extract was evaluated for its total phenolics content (TPC), total flavonoids content (TFC) and its antioxidant and antibacterial activities. Under the optimum conditions (5 min for the irradiation time, 40% for the amplitude, 80% for ethanol concentration and 50% for solid-liquid ratio) the TPC was 12.23 ± 1.01 mg Gallic Acid Equivalent/gram of Dried Powder (mg GAE/g DP) which is very close with experimental assay. The TPC are better preserved at A whereas TFC and the antioxidant activity at F, and the antibacterial activity depend on the storage methods and the strains tested.

Optimization, Metabolomic Analysis, Antioxidant Potential andDepigmenting Activity of Polyphenolic Compounds fromUnmature Ajwa Date Seeds (Phoenix dactylifera L.) Using Ultrasonic-Assisted Extraction

This study sought to optimize the ultrasonic-assisted extraction of polyphenolic compounds from unmature Ajwa date seeds (UMS), conduct untargeted metabolite identification and assess antioxidant and depigmenting activities. Response surface methodology (RSM) utilizing the Box-Behnken design (BBD) and artificial neural network (ANN) modeling was applied to optimize extraction conditions, including the ethanol concentration, extraction temperature and time. The determined optimal conditions comprised the ethanol concentration (62.00%), extraction time (29.00 min), and extraction temperature (50 °C). Under these conditions, UMS exhibited total phenolic content (TPC) and total flavonoid content (TFC) values of 77.52 ± 1.55 mgGAE/g and 58.85 ± 1.12 mgCE/g, respectively, with low relative standard deviation (RSD%) and relative standard error (RSE%). High-resolution mass spectrometry analysis unveiled the presence of 104 secondary metabolites in UMS, encompassing phenols, flavonoids, sesquiterpenoids, lignans and fatty acids. Furthermore, UMS demonstrated robust antioxidant activities in various cell-free antioxidant assays, implicating engagement in both hydrogen atom transfer and single electron transfer mechanisms. Additionally, UMS effectively mitigated tert-butyl hydroperoxide (t-BHP)-induced cellular reactive oxygen species (ROS) generation in a concentration-dependent manner. Crucially, UMS showcased the ability to activate mitogen-activated protein kinases (MAPKs) and suppress key proteins including tyrosinase (Tyr), tyrosinase-related protein-1 and -2 (Trp-1 and -2) and microphthalmia-associated transcription factor (MITF), which associated melanin production in MNT-1 cell. In summary, this study not only optimized the extraction process for polyphenolic compounds from UMS but also elucidated its diverse secondary metabolite profile. The observed antioxidant and depigmenting activities underscore the promising applications of UMS in skincare formulations and pharmaceutical developments.

PhInd-Database on Polyphenol Content in Agri-Food By-Products and Waste: Features of the Database

Timely access to topic-relevant datasets is of paramount importance for the development of any successful strategy (food waste reduction strategy), since datasets illuminate opportunities, challenges and development paths. PhInd is the first comprehensive database on polyphenol content in plant-based by-products from the agri-food sector or the wastewater sector and was developed using peer-reviewed papers published in the period of 2015-2021. In total, >450 scientific manuscripts and >6000 compound entries were included. Database inclusion criteria were polyphenol contents = determined using HPLC/UHPLC quantitative methods. PhInd can be explored through several criteria which are either 'open' or checkboxes. Criteria are given in subsections: (a) plant source; (b) by-product industrial processing; (c) pre-treatment of by-products before the isolation of polyphenols; and (d) the extraction step of polyphenols. Database search results could be explored on the website directly or by downloading Excel files and graphs. This unique database content is beneficial to stakeholders-the food industry, academia, government and citizens.

Extraction and Emulsification of Carotenoids from Carrot Pomaces Using Oleic Acid

This study aimed to use oleic acid-based ultrasonic-assisted extraction (UAE) to recover carotenoids from carrot pomace and emulsify the enriched-carotenoid oleic acid using spontaneous and ultrasonic-assisted emulsification. The extraction performance of oleic acid was compared with traditional organic solvents, including hexane, acetone, and ethyl acetate. The one-factor experiments were employed to examine the impact of UAE conditions, including liquid-to-solid ratios, temperature, ultrasonic power, and time, on the extraction yield of carotenoids and to find the conditional ranges for the optimization process. The response surface methodology was employed to optimize the UAE process. The second-order extraction kinetic model was used to find the mechanism of oleic acid-based UAE. After that, the enriched-carotenoid oleic acid obtained at the optimal conditions of UAE was used to fabricate nanoemulsions using spontaneous emulsification (SE), ultrasonic-assisted emulsification (UE), and SE-UE. The effect of SE and UE conditions on the turbidity of nanoemulsion was determined. Then, the physiochemical attributes of the nanoemulsion from SE, UE, and spontaneous ultrasonic-assisted emulsification (SE-UE) were determined using the dynamic light scattering method. The extraction yield of carotenoids from carrot pomace by using sonication was the highest. The adjusted optimal conditions were 39 mL/g of LSR, 50 °C, 12.5 min, and 350 W of ultrasonic power. Under optimal conditions, the carotenoid content attained was approximately 163.43 ± 1.83 μg/g, with the anticipated value (166 μg/g). The particle sizes of nanoemulsion fabricated at the proper conditions of SE, UE, and SE-UE were 31.2 ± 0.83, 33.8 ± 0.52, and 109.7 ± 8.24 nm, respectively. The results showed that SE and UE are suitable methods for fabricating nanoemulsions. The research provided a green approach for extracting and emulsifying carotenoids from carrot pomace.

Optimization of Alkali Treatment for Production of Fermentable Sugars and Phenolic Compounds from Potato Peel Waste Using Topographical Characterization and FTIR Spectroscopy

Potato peel waste (PPW) was utilized as a bio-template for the production of valuable compounds such as reducing sugars (RS), total sugar (TS) and total phenolic compounds (TPC). Two methods of alkali treatments, i.e., chemical (NaOH) and thermochemical (NaOH assisted with autoclaving) processes, were employed for the deconstruction of PPW. Response surface methodology (RSM) was used to study the effects of alkali concentration (0.6-1.0 w/v), substrate concentration (5-15 g) and time (4-8 h) on the extraction of RS, TS and TP from PPW. The application of alkali plus steam treatment in Box-Behnken design (BBD) with three levels yielded the optimum releases of RS, TS and TP as 7.163, 28.971 and 4.064 mg/mL, respectively, corresponding to 10% substrate loading, in 0.6% NaOH for 8 h. However, the alkali treatment reported optimum extractions of RS, TS and TP as 4.061, 17.432 and 2.993 mg/mL, respectively. The thermochemical pretreatment was proven a beneficial process as it led to higher productions of TP. FTIR and SEM were used to analyze the deterioration levels of the substrate. The present work was used to explore the sustainable management of PPW, which is a highly neglected substrate bioresource but is excessively dumped in open environment, raising environmental concerns. The cost-effective methods for the breakdown of PPW starch into fermentable sugars might be utilized to extract valuable compounds.

A Comparative Study of Ethanol and Citric Acid Solutions for Extracting Betalains and Total Phenolic Content from Freeze-Dried Beetroot Powder

This research compares the extraction of betalains (betacyanin and betaxanthin) and total phenolic content using citric acid and aqueous-ethanol solutions. The aim is to find an environmentally sustainable alternative solvent for extracting these compounds from dried beetroot powder. Using citric acid solution as a solvent offers several benefits over ethanol. Citric acid is a weak organic acid found naturally in citrus fruits, making it a safe and environmentally friendly choice for certain extraction processes. Moreover, the use of citric acid as solvent offers biodegradability, non-toxicity, non-flammability, and is cost effective. A full factorial design and response surface methodology (RSM) were employed to assess the effects of extraction parameters (extraction time (5-30 min), extraction temperature (20, 30, 40 °C), pH of citric acid solution (3, 4, 5) and ethanol concentration (10, 20, 30% v/v)). The yield was determined spectrophotometrically and expressed as mg/g of dry powder. The results showed that citric acid solution yielded 85-90% of the ethanolic extract under identical conditions. The maximum yields of betacyanin, betaxanthin, and total phenolic content in citric acid solution were 3.98 ± 0.21 mg/g dry powder, 3.64 ± 0.26 mg/g dry powder, and 8.28 ± 0.34 mg/g dry powder, respectively, while aqueous-ethanol yielded 4.38 ± 0.17 mg/g dry powder, 3.95 ± 0.22 mg/g dry powder, and 8.45 ± 0.45 mg/g dry powder. Optimisation resulted in maximum extraction yields of 90% for betalains and 85% for total phenolic content. The study demonstrates the potential of citric acid as a viable alternative to polar organic solvents for extracting phytochemicals from plant material, providing comparable results to aqueous-ethanol. Artificial Neural Network (ANN) models outperformed RSM in predicting extraction yields. Overall, this research highlights the importance of exploring bio-solvents to enhance the environmental sustainability of phytochemical extraction.

Optimization of Ethanolic Extraction of Phenolic Antioxidants from Lychee and Longan Seeds Using Response Surface Methodology

Lychee seeds (LS) and longan seeds (LoS) are excellent sources of phenolic compounds (PCs) with strong antioxidant activity (AOA). The aim of this study was to optimize the extraction conditions regarding extraction yield (EY), extractable phenolic compound (EPC), and AOA from LS and LoS using surface response methodology (RSM). Solvent concentration, extraction temperature, time, and solid to liquid ratio were optimized using RSM. Increasing the solid to solvent ratio from 1:05 to 1:40 (w/v), increased EY for LoS, however, EY did not change from 1:20 to 1:40 for LS. Solid-liquid ratio 1:20 was chosen for this study. Increasing the quantity of solvent leads to higher EPC and FRAP. The results showed that LoS exhibited higher AOA than LS measured as DPPH, ABTS, and FRAP, respectively. Ethanol concentrations and temperatures significantly (p < 0.05) affect EY, EPC, and AOA. The results (R2 > 0.85) demonstrated a good fit to the suggested models and a strong correlation between the extraction conditions and the phenolic antioxidant responses. The ethanol concentrations of 41 and 53%, temperatures of 51 and 58 °C, and the corresponding times of 139 and 220 min were the optimal conditions that maximized the EY, EPC, and AOA from LS and LoS.

Antioxidant and Anticancer Assessment and Phytochemical Investigation of Three Varieties of Date Fruits

Date palm (Phoenix dactylifera L.) fruits contain high concentrations of phenolic compounds, particularly flavonoids and other micronutrients, which impact human health due to their potent antioxidant, anti-inflammatory, and anticancer characteristics. In the present study, the effect of ethyl acetate, hydroethanol, hydromethanol, and aqueous extract from three date palm varieties (i.e., Ajwa, Siwi, and Sukkari) on phytochemical profiles and antioxidant and anticancer activities was investigated. Fruit extracts were screened for their antioxidant activity using the DPPH· method. Phenolic constituents were quantified and identified using HPLC-DAD. Extracts (ethyl acetate, hydroethanol, and hydromethanol) were assessed for cytotoxicity on nine human cancer cell lines, i.e., MG-63, HCT116, MCF7, MDA-MB-231, HEPG2, HUH7, A549, H460, and HFB4, using the sulphorhodamine-B (SRB) assay. Results showed that the ethyl acetate extract of the Sukkari fruits has the greatest antioxidant potential with an IC₅₀ value of 132.4 ± 0.3 μg·mL^-1, while the aqueous extract of Ajwa date fruits exhibited the lowest antioxidant effect with an IC₅₀ value of 867.1 ± 0.3 μg·mL^-1. The extracts exhibited potent to moderate anticancer activities against the investigated cancer cell line in a source-dependent manner. Methanol extract of Siwi fruits exhibited the most potent anticancer activity (IC₅₀ = 99 ± 1.6 µg·mL^-1), followed by the same extract of Sukkari fruits with an IC₅₀ value of 119 ± 3.5 µg·mL^-1 against the cell line of human breast cancer (MDA-MB-231). Additionally, principal component analysis (PCA) was investigated to determine the relationship among the investigated traits and treatments. Our findings reveal that date palm fruit-derived extracts are excellent sources of biologically active constituents and substantiate their potential use in new anticancer strategies from natural resources.

Effect of Different Extraction Methods on the Total Phenolics of Sugar Cane Products

The health benefits of sugar cane products are attributed to certain antioxidant compounds in plant materials. The presence of antioxidants in plant materials depends on the extraction method in terms of yield and the number of phenolic compounds identified. This study was carried out to evaluate the performance of the three extraction methods, which were selected from previous studies to show the effect of the extraction method on the content of antioxidant compounds in different types of sugar. This study also evaluates the potential of different sugar extracts in anti-diabetic activity based on in vitro assays (α-glucosidase and α-amylase). The results showed that sugar cane extracted with acidified ethanol (1.6 M HCl in 60% ethanol) was the best condition to extract a high yield of phenolic acids compared to other methods. Among the three types of sugar, less refined sugar (LRS) showed the highest yield of phenolic compounds, 57.72 µg/g, compared to brown sugar (BS) and refined sugar (RS) sugar, which were at 42.19 µg/g and 22.06 µg/g, respectively. Whereas, among the sugar cane derivatives, LRS showed minor and BS moderate inhibition towards α-amylase and α-glucosidase activity compared to white sugar (RS). Thus, it is suggested that sugar cane extracted with acidified ethanol (1.6 M HCl in 60% ethanol) is the optimum experimental condition for antioxidant content determination and provides a basis for further exploitation of the health-beneficial resources of the sugarcane products.

Emerging natural and high-phenolic sweet substances: A review

Emerging high-phenolic sweeteners impart a sweet taste to foods and beverages, and are desirable sugar alternatives. Most refined sugars have a low antioxidant content due to polyphenol degradation occurring during sugar refining. Natural sweeteners such as honey, molasses, and dark brown sugar possess moderate to high phenolic content. Other phytochemicals found in natural sweeteners are carotenoids, organic acids, and terpenoids. Additionally, molasses and syrups synthesised from anthocyanin-rich fruits and roots contain anthocyanins apart from flavonoids. Non-nutritive sweeteners, such as sugar alcohols, are low in calories besides their sweet taste. Sweet proteins, dihydrochalcones, phenolics, and terpenoid derivatives are emerging sweeteners. These sweet substances are effective antioxidants that could help reduce oxidative stress in the human body although the amount ingested is usually low. The present review emphasised specific natural, high-phenolic, and other sweet compounds, and examined the antioxidative characteristics of these sweeteners. The risk of excessive ingestion of these sweet substances is yet to be proven.

Ultrasound-assisted green extraction methods: An approach for cosmeceutical compounds isolation from Macadamia integrifolia pericarp

This study aimed was to examine the potential of several green extraction methods to extract cosmetic/cosmeceutical components from Macadamia integrifolia pericarps, which were a by-product of the macadamia nut industry. M. integrifolia pericarps were extracted by conventional solvent extraction process using 95% v/v ethanol and various green extraction methods, including infusion, ultrasound, micellar, microwave, and pulsed electric field extraction using water as a clean and green solvent. The extracts were evaluated for total phenolic content using Folin-Ciocalteu method.The antioxidant activities were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing/antioxidant power, and ferric-thiocyanate method. The anti-skin ageing activities were investigated by means of collagenase, elastase, and hyaluronidase inhibition using enzyme-substrate reaction assay. The irritation profile of the extracts was evaluated by the hen's egg test-chorioallantoic membrane (HET-CAM) test. The results noted that ultrasound-assisted extraction yielded the significantly highest extract amount with the significantly highest total phenolic content (p < 0.05), especially when the extraction time was 10 min. The aqueous extract from ultrasound-assisted extraction possessed the most potent antioxidant and anti-skin ageing activities (p < 0.05). Its antioxidant activities were comparable to ascorbic acid and Trolox, whereas the anti-skin ageing activities were equivalent to epigallocatechin-3-gallate and oleanolic acid. Besides, the extract was safe since it induced no irritation in the HET-CAM test. Therefore, ultrasound-assisted extraction was suggested as an environmentally friendly extraction method for M. integrifolia pericarp extraction and further application in the cosmetic/cosmeceutical industries.

Ultrasonic assisted extraction of polyphenols from bayberry by deep eutectic supramolecular polymer and its application in bio-active film

Ultrasound and deep eutectic supramolecular polymers (DESP) is a novel combination of green extraction method for phytochemicals. In this study, a new type of green extractant was developed: DESP. It is a derivative of deep eutectic solvent (DES) and was prepared by supramolecular polymer unit β-cyclodextrin (β-CD) as hydrogen bond acceptor (HBA) and organic acid as hydrogen bond donor (HBD). The current work focuses on the use of ultrasonic-assisted (UAE) DESP extraction of polyphenolic compounds (PCs) from bayberry. The experimental results showed that DESP synthesized with β-CD and lactic acid (LA) in a ratio of 1:1 (w/w %) had the best extraction effect. And by using a three-level factor experiment and the response surface method, the predicted TPC content is very close to the actual content (28.85 ± 1.27 mg GAE/g). The DESP extract including PCs were further used as plasticizer for chitosan (CS) to prepare highly active green biofilms (DESP-CS). It is possible to reduce the tedious procedures for separating biologically active substances from DESP. The experiment proved that the prepared films have good mechanical properties, plastic deformation resistance, thermal stability and antioxidant activity.

Extraction Systems and Analytical Techniques for Food Phenolic Compounds: A Review

Phenolic compounds are highly valuable food components due to their potential utilisation as natural bioactive and antioxidant molecules for the food, cosmetic, chemical, and pharmaceutical industries. For this purpose, the development and optimisation of efficient extraction methods is crucial to obtain phenolic-rich extracts and, for some applications, free of interfering compounds. It should be accompanied with robust analytical tools that enable the standardisation of phenolic-rich extracts for industrial applications. New methodologies based on both novel extraction and/or analysis are also implemented to characterise and elucidate novel chemical structures and to face safety, pharmacology, and toxicity issues related to phenolic compounds at the molecular level. Moreover, in combination with multivariate analysis, the extraction and analysis of phenolic compounds offer tools for plant chemotyping, food traceability and marker selection in omics studies. Therefore, this study reviews extraction techniques applied to recover phenolic compounds from foods and agri-food by-products, including liquid-liquid extraction, solid-liquid extraction assisted by intensification technologies, solid-phase extraction, and combined methods. It also provides an overview of the characterisation techniques, including UV-Vis, infra-red, nuclear magnetic resonance, mass spectrometry and others used in minor applications such as Raman spectroscopy and ion mobility spectrometry, coupled or not to chromatography. Overall, a wide range of methodologies are now available, which can be applied individually and combined to provide complementary results in the roadmap around the study of phenolic compounds.

Agri-Food Waste from Apple, Pear, and Sugar Beet as a Source of Protective Bioactive Molecules for Endothelial Dysfunction and Its Major Complications

Endothelial damage is recognized as the initial step that precedes several cardiovascular diseases (CVD), such as atherosclerosis, hypertension, and coronary artery disease. It has been demonstrated that the best treatment for CVD is prevention, and, in the frame of a healthy lifestyle, the consumption of vegetables, rich in bioactive molecules, appears effective at reducing the risk of CVD. In this context, the large amount of agri-food industry waste, considered a global problem due to its environmental and economic impact, represents an unexplored source of bioactive compounds. This review provides a summary regarding the possible exploitation of waste or by-products derived by the processing of three traditional Italian crops-apple, pear, and sugar beet-as a source of bioactive molecules to protect endothelial function. Particular attention has been given to the bioactive chemical profile of these pomaces and their efficacy in various pathological conditions related to endothelial dysfunction. The waste matrices of apple, pear, and sugar beet crops can represent promising starting material for producing "upcycled" products with functional applications, such as the prevention of endothelial dysfunction linked to cardiovascular diseases.

Optimization of the ultrasonic-assisted extraction process to obtain total phenolic and flavonoid compounds from watermelon (Citrullus lanatus) rind

This context presents the study of ultrasonic-assisted extraction (UAE) to obtain phenolic and flavonoid compounds from watermelon rind powder (WRP). The antioxidant activity of the extracts was investigated using DPPH and ABTS⁺ assays. One-factor experiments were conducted to examine the effect of each factor (solid-to-liquid ratio (SLR), acetone concentration (AC), temperature, and time) on the UAE of WRP. Box-Behnken Design (BDD) model was employed to optimize the UAE conditions based on total phenolic contents (TPC), total flavonoid content (TFC), and their antioxidant activities. The optimal conditions were 1:30.50 SLR, 70.71% AC, 29.78 °C, and 10.65 min extraction time. There were no significant differences between predicted and experimental results (less than 6.0%), recommending a feasible and innovative process of deploying UAE to extract phenolics and flavonoids effectively from watermelon rind.

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Sonication increases the extraction of total phenolic and flavonoid contents.

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Sonication increases the antioxidant activity of watermelon rind extracts.

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Box-Behnken Design model is used to optimize ultrasonic-assisted extraction conditions.

Celery Root Phenols Content, Antioxidant Capacities and Their Correlations after Osmotic Dehydration in Molasses

The osmotic dehydration (OD) of celery root in sugar beet molasses was studied at three temperatures (20, 35, and 50 °C) and three immersion periods (1, 3, and 5 h) in order to examine the changes in antioxidant potential and phenolic profile of celery root throughout the process. The antioxidant capacity (AOC) of dehydrated samples was evaluated by spectrophotometric and polarographic assays, the total phenolic content by the Folin-Ciocalteu method, and the individual phenolic compounds by HPLC-DAD. As a result of OD in molasses, the AOC and phenols content in samples increased proportionally to the augmentation of temperature and the immersion time. Vanillic acid, syringic acid, and catechin were detected in dehydrated samples as a result of transfer from molasses. Compared to fresh celery root, the content of identified phenols in osmodehydrated samples was improved from 1.5 to 6.2 times. Strong correlations between applied assays were obtained, except for the DPPH. Based on the correlation analysis chlorogenic acid, gallic acid, chrysin, catechin, and kaempferol showed the greatest contribution to the overall AOC of osmodehydrated celery root. Molasses, an agro-industrial waste from sugar production, could be valorized as a valuable osmotic solution.

Valorization of Low-Cost Substrates for the Production of Odd Chain Fatty Acids by the Oleaginous Yeast Yarrowia lipolytica

Odd-chain fatty acids (OCFAs) have recently gained interest as target compounds in microbial production due to their diverse applications in the medical, pharmaceutical and chemical industries for the production of biofuels. Yarrowia lipolytica is a promising oleaginous yeast that has the ability to accumulate high quantities of fatty acids. However, the use of Y. lipolytica oils is still under research, in order to decrease the production costs related to the fermentation process and improve economic feasibility. In this work, sugar beet molasses (10–50 g/L) and crude glycerol (30 g/L) were used as the main carbon sources to reduce the processing costs of oil production from a genetically engineered Y. lipolytica strain. The effects of medium composition were studied on biomass production, lipid content, and OCFAs profile. Lipid production by yeast growing on molasses (20 g/L sucrose) and crude glycerol reached 4.63 ± 0.95 g/L of culture medium. OCFAs content represented 58% of the total fatty acids in lipids, which corresponds to ≈2.69 ± 0.03 g/L of culture medium. The fermentation was upscaled to 5 L bioreactors and fed-batch co-feeding increased OCFA accumulation in Y. lipolytica by 56% compared to batch cultures.

Utilization of Nanotechnology to Improve the Application and Bioavailability of Phytochemicals Derived from Waste Streams

Phytochemicals are relatively small molecular species found in edible plants that may exhibit a diverse range of techno- and biofunctional attributes. In particular, there has been great interest in the identification, isolation, and utilization of dietary phytochemicals that can be used as natural pigments, antioxidants, or antimicrobials or that may improve human health and wellbeing by preventing chronic diseases, such as cardiovascular diseases, diabetes, obesity, and cancer. Relatively high levels of these phytochemicals are often present in the waste streams produced by the food and agriculture industry, such as the peels, stems, roots, or leaves of plants, that are normally discarded or turned into animal foods. From an economic and environmental perspective, it would be advantageous to convert these waste streams into value-added functional ingredients, which is consistent with the creation of a more circular economy. Bioactive phytochemicals can be isolated from agricultural and food waste streams using green extraction methods and then incorporated into plant-based functional foods or biodegradable active packaging materials. The utilization of phytochemicals in the food industry is often challenging. They may chemically degrade in the presence of light, heat, oxygen, and some pH conditions, thereby altering their biological activity. They may have low solubility in aqueous solutions and gastrointestinal fluids, thereby making them difficult to introduce into foods and leading to a low bioavailability. These challenges can sometimes be overcome using nanoencapsulation, which involves trapping the phytochemicals inside tiny food-grade particles. These nanoparticles may be assembled from edible lipids, proteins, carbohydrates, and/or surfactants and include nanoemulsions, solid lipid nanoparticles, nanoliposomes, and biopolymer nanoparticles. In this manuscript, we review a number of important phytochemicals and nanoencapsulation methods used to improve their efficacy.

A novel strategy for producing nano-particles from date seeds and enhancing their phenolic content and antioxidant properties using ultrasound-assisted extraction: A multivariate based optimization study

Date seeds from the date palm fruit are considered as a waste and they are known to contain several bioactive compounds. Producing nanoparticles from the date seeds can enhances their effectiveness and their utilization as novel functional food ingredients. In this study, date seed nanoparticles (DSNPs) synthesized using acid (HCl) hydrolysis method (HCl concentration of 38% and hydrolysis time of 4 days) was found to have particle size between 50 and 150 nm. The obtained DSNPs were characterized by measuring particle size and particle charge (Zetasizer), morphology using scanning electron microscope (SEM), and determination of the functional groups using fourier-transform infrared spectroscopy (FTIR). DSNPs were further treated with green extraction technology [ultrasound-assisted extraction (UAE)] using water-based and methanol-based solvent for optimizing the extraction of the bioactive compounds by implementing response surface methodology (RSM). The UAE of DSNPs were analysed for set of responses including total phenolic content (TPC), total flavonoid content (TFC), 1,1-diphenyl-2-picrlthydrazyl (DPPH) radical scavenging activity, ferric ion reducing antioxidant power (FRAP), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity. Three-factor and four-factor Box-Behnken design (BBD) of three models (Synthesis of DSNPs, UAE with water, and UAE with methanol) was performed. The results showed that in UAE of DSNPs using water-based solvent, the key independent factors effecting the TPC and TFC and antioxidant activities were S:L ratio (40:1 mg/ml) and treatment time (9 min). Whereas the methanol-based UAE of DSNPs was mostly affected by US amplitude/power (90%) and methanol concentration (80%). All models were further optimized using response optimizer in Minitab and the generated predicted values were very comparable to the actual obtained results which confirm the significance and validity of all RSM models used. The phenolic compounds identified from DSNPs consisted mainly of 3,4-Dihydroxy benzoic acid, ferulic acid, and p-coumaric acid. The present study demonstrated a successful method for synthesising DSNPs as well as documented the optimum UAE conditions to maximize the extraction of polyphenolic compounds from DSNPs and enhancing their antioxidant activities to be used in food application.

Optimum Conditions and LC-ESI-MS Analysis of Phenolic Rich Extract from Eucalyptus marginata L. under Maceration and Ultrasound-Assisted Extraction Methods Using Response Surface Methodology

Eucalyptus marginata L. has a significant value in traditional medicine and recently has been shown to possess many pharmacological properties in vitro. The main goal of the present study was to optimize the extraction parameters of phenolic compounds from Eucalyptus marginata L. leaves using the extraction technique assisted by ultrasound in comparison with maceration using response surface methodology as a predicted tool. Therefore, total phenolic and flavonoid contents have been optimized, taking into account four variables: extraction time, temperature, liquid-to-solid ratio, and ethanol concentration. The optimum ultrasound-assisted extraction method for total phenolic and total flavonoid contents was obtained by ensuring the following parameters: t = 49.9 min, T = 74.9°C, liquid-to-solid ratio = 39.5 ml/g, and ethanol = 58.48%. The optimum extract has been subjected to LC-ESI-MS analysis. This technique allowed us to identify ten phenolic compounds: four phenolic acids mainly gallic acid (27.77 ± 0.06 µg/g DW) and protocatechuic acid (37.66 ± 0.04 µg/g DW) and six flavonoid compounds such as quercetrin (150.78 ± 0.02 µg/g DW) and hyperoside (39.19 ± 0.03 µg/g DW). These green and efficient procedures should be a promising option to guide industrial design for the production of phenolic-rich plant extracts.

Extraction of phenolic compounds from the shells of pecan nuts with cytotoxic activity through apoptosis against the colon cancer cell line HT-29

The water extraction of phenolic compounds from two varieties ("Mahan" and "Marameck") of pecan nutshells (Carya illinoinensis) without and with sonication, varying the solvent/solid ratio (S), the pH, and the refluxing time (t), was studied. Additionally, the in vitro cytotoxicity and the determination of the cell death mechanism of the extracts against the colon cancer cell line HT-29 were investigated. The content of total phenolic compounds (TPC) of "Marameck" nutshells resulted higher than for the "Mahan" variety, and the pH increase resulted in higher TPC contents for both cultivars. The optimized conditions for TPC extraction without and with sonication resulted: S = 33 ml/g, pH = 12, and t = 9.6 min, and yielded ≈ 70 and 90 mg/g of TPC for "Mahan" and "Marameck" nutshells, respectively. The optimized extracts of pecan nutshells without sonication from both cultivars presented similar cytotoxicity against HT-29 colon cancer cells (IC₅₀  ≈ 50 µg/ml), higher than for sonicated extracts (IC₅₀ ≈ 88 and 138 µg/ml for "Mahan" and "Marameck," respectively). Cell death through apoptosis was the main mechanism of cell death induced by the nutshell extracts. PRACTICAL APPLICATION: The extraction of phenolic compounds (TPC) from the residues of two varieties of pecan nutshells ("Mahan" and "Marameck") was studied. An optimal combination of variables within the pH range that minimizes the solvent-to-solid ratio (S) and the time of refluxing (t), saving at the same time, water and energy, was set up. The phenolic compound extracts obtained from the residues of the pecan nuts exhibit cytotoxic effects against colon cancer cells and could be of interest as an alternative treatment of different types of cancer. Additionally, these extracts may be of importance to the food industry as they can be used as antioxidant agents in food formulation. Also, the high levels of anthocyanidins obtained from the pecan nut extracts after proanthocyanidins' strong acid hydrolysis can be purified and employed as natural red dyes.

New insights of phenolic compounds from optimized fruit extract of Ficus auriculata

In this study, the extraction conditions extracted maximize amounts of phenolic and bioactive compounds from the fruit extract of Ficus auriculata by using optimized response surface methodology. The antioxidant capacity was evaluated through the assay of radical scavenging ability on DPPH and ABTS as well as reducing power assays on total phenolic content (TPC). For the extraction purpose, the ultrasonic assisted extraction technique was employed. A second-order polynomial model satisfactorily fitted to the experimental findings concerning antioxidant activity (R2 = 0.968, P < 0.0001) and total phenolic content (R2 = 0.961, P < 0.0001), indicating a significant correlation between the experimental and expected value. The highest DPPH radical scavenging activity was achieved 85.20 ± 0.96% at the optimum extraction parameters of 52.5% ethanol (v/v), 40.0 °C temperature, and 22 min extraction time. Alternatively, the highest yield of total phenolic content was found 31.65 ± 0.94 mg GAE/g DF at the optimum extraction conditions. From the LC-ESI-MS profiling of the optimized extract, 18 bioactive compounds were tentatively identified, which may regulate the antioxidant activity of fruits of F. auriculata.

Cocktail enzyme-assisted alkaline extraction and identification of jujube peel pigments

Jujube peel (JP) is rich in pigments, which appears red to deep red in color. This study optimized conditions for cocktail enzyme-assisted extraction of jujube peel pigments based on response surface method (RSM). A Box-Behnken design (BBD) was utilized to analyze the effects of buffer liquid volume (BLV), pH, temperature, and incubation time on the total polyphenols content (TPC), total flavonoids content (TFC) and color (L*, a*, b*). Optimal extraction conditions, for the highest concentrations of TPC, TFC and a* values, were 16 mL BLV, pH 7.0, temperature 43 °C, and incubation time 97 min. Finally, concentrations and identities of the eight main constituents (p-coumaric acid, (-)-epicatechin, quercetin-3-O-robinobioside, rutin, kaempferol 3-O-robinobioside, quercetin 3-O-α-l-arabinosyl-(1 → 2)-α-l-rhamnoside, quercetin 3-O-β-d-xylosyl-(1 → 2)-α-l-rhamnoside, quercetin) in jujube peel pigments were determined using UPLC-MS/MS. The study provides guidance for valorisation of jujube peel, specifically valuable food-safe pigments, during industrial production.

Recent trends in extraction of plant bioactives using green technologies: A review

Phenolic compounds from plant sources have significant health-promoting properties and are known to be an integral part of folk and herbal medicines. Consumption of phenolics is known to alleviate the risk of various lifestyle diseases including cancer, cardiovascular, diabetes, and Alzheimer's. In this context, numerous plant crops have been explored and characterized based on phenolic compounds for their use as supplements, nutraceutical, and pharmaceuticals. The present review highlights some important source of bioactive phenolic compounds and novel technologies for their efficient extraction. These techniques include the use of microwave, ultrasound, and supercritical methods. Besides, the review will also highlight the use of response surface methodology (RSM) as a statistical tool for optimizing the recoveries of the phenolic bioactives from plant-based matrices.

Soybean (Glycine max) hull valorization through the extraction of polyphenols by green alternative methods

Soybean is one of the greatest crops in the world, with about 348.7 million tons being produced in 2018. Soybean hull is a by-product produced during the processing of soybean to obtain flour and oil. Though not being actually exploited, it is a source of polyphenols with antioxidant activity. Here, the extraction of polyphenols from soybean hull was performed by means of an alkaline hydrolysis treatment, which was optimized by the response surface methodology. At the optimal region, a total phenolic content of 0.72 g gallic acid equivalents per 100 g of soybean hull was obtained with an antioxidant activity of 2.17 mmoles of Trolox equivalents. Polyphenols responsible for the antioxidant activities were identified by LC-MS, including phenolic acids, anthocyanins, stilbenes, and the two main isoflavones of soybean, daidzein and genistein, in their non-glycosylated form. Other alternative extraction methods based on Aspergillus oryzae fermentation and α-amylase hydrolysis are also proposed.

Ultrasound-Assisted Deep Eutectic Solvent Extraction of Anthocyanins from Blueberry Wine Residues: Optimization, Identification, and HepG2 Antitumor Activity

Blueberry wine residues produced during the wine-brewing process contain abundant anthocyanins and other bioactive compounds. To extract anthocyanins from blueberry wine residues more efficiently, a novel procedure of ultrasound-assisted deep eutectic solvent extraction (UADESE) was proposed in this work. The extraction process was optimized by response surface methodology coupled with genetic algorithm. The optimum extraction parameters to achieve the highest yield of anthocyanins (9.32 ± 0.08 mg/g) from blueberry wine residues by UADESE were obtained at water content of 29%, ultrasonic power of 380 W, extraction temperature of 55 °C, and extraction time of 40 min. The AB-8 macroporous resin combined with Sephadex LH-20 techniques was used to purify the crude extract (CE) obtained under optimum extraction conditions and analyze the anthocyanins composition by HPLC-ESI-MS/MS. The cyanidin-3-rutinoside with purity of 92.81% was obtained. The HepG2 antitumor activity of CE was better than that of the purified anthocyanins component. Moreover, CE could increase the intracellular reactive oxygen species levels and the apoptosis, and arrest HepG2 cells in the S phases. These findings provided an effective and feasible method for anthocyanins extraction, and reduced the environmental burden of this waste.

Ultrasound-assisted enzymatic extraction of anthocyanins from grape skins: optimization, identification, and antitumor activity

Grape skins produced during the grape juice production and processing contain abundant anthocyanins and other active compounds. Consequently, this study optimized the extraction conditions for ultrasound-assisted enzymatic extraction (UAEE) of anthocyanins from grape skins via response surface methodology coupled with genetic algorithm. The optimum extraction parameters to achieve the highest anthocyanins yield (3.01 ± 0.04) mg/g from grape skins by UAEE were obtained under an extraction temperature of 50 °C, ultrasonic power of 400 W, pectinase dosage of 0.16%, and extraction time of 28 min. The AB-8 macroporous resin combined Sephadex LH-20 techniques were further employed to purify the anthocyanins extracts obtained under optimum extraction conditions (AEOEC), and the main anthocyanins were identified using high-performance liquid chromatography tandem mass spectrometry. The purified anthocyanins contained two anthocyanins in terms of delphinidin-3,5-O-diglucoside and cyanidin-3-O-rutinoside with purity of 91.35% and 92.64%, respectively. Ultimately, we further evaluated the antitumor activity of AEOEC and two purified anthocyanins on breast cancer. The results indicated that the antitumor effect of AEOEC on breast cancer MCF-7 cells was better than that of two purified anthocyanins. In addition, AEOEC could memorably increase intracellular reactive oxygen species levels and apoptosis of MCF-7 cells, and arrest MCF-7 cells in the G2/M phases. The findings provide an effective and feasible method for anthocyanins extraction and reduce the environmental burden of this waste.

Optimization Ultrasound-Assisted Deep Eutectic Solvent Extraction of Anthocyanins from Raspberry Using Response Surface Methodology Coupled with Genetic Algorithm

Raspberries have been reported to contain abundant anthocyanins and other active compounds. To extract anthocyanins from raspberries more efficiently, a novel procedure of ultrasound-assisted deep eutectic solvent extraction (UADESE) was proposed in this paper. The extraction process was optimized by response surface methodology coupled with a genetic algorithm. The optimum extraction parameters to achieve the highest yield of anthocyanins 1.378 ± 0.009 mg/g from raspberry powder via UADESE were obtained at a water content of 29%, ultrasonic power of 210 W, extraction temperature of 51 °C and extraction time of 32 min. The AB-8 macroporous resin combined with the high-speed counter current chromatography (HSCCC) method were further used to isolate and purify the anthocyanins extracts obtained under optimum extraction conditions, and the structure of purified anthocyanins components were identified by UV-Visible spectrophotometer (UV-Vis), high-performance liquid chromatography (HPLC), high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS/MS), ¹H nuclear magnetic resonance (NMR) and ¹³C-NMR spectra. The two anthocyanins (cyanidin-3-glucoside with a purity of 92.25% and cyanidin-3-rutinoside with a purity of 93.07%) identified were consistent with those present in raspberries. These findings provided an effective and feasible method for extraction, isolation and purification of anthocyanins from natural plant resources.

Antioxidant activity, nutritional and physicochemical characteristics, and toxicity of minimally refined brown sugar and other sugars

Minimally refined brown sugar (MRBS) is a brown sugar derived from sugarcane that has a low glycemic index. This study aimed to determine and compare the antioxidant contents and nutritional and physicochemical properties of MRBS, refined sugar (RS), and brown sugar (BS). In addition, the toxicity of these sugars was evaluated via in vitro cytotoxicity method and by using a zebrafish model. Results showed that MRBS was better than the two other sugars because it has a lower moisture content and higher ash content. The contents of potassium and manganese of MRBS were higher than those of the two other sugars. Surprisingly, MRBS also contained selenium, which was not detected in RS and BS. The major phenolics in MRBS are 4-hydroxybenzoic acid, chlorogenic acid, protocatechuic acid, trans-Ferulic acid, and apigenin. All sugar solutions and their antioxidant-containing extracts were not cytotoxic to 3T3-L1 adipocytes.