Extraction of antioxidant and antimicrobial compounds from Inga marginata Willd bark and pulp using different extraction techniques and phytochemical characterization

This study aimed to identify the least aggressive and highest yield extraction method to obtain bioactive compounds from Inga marginata Willd fruits, determine the chemical components, and evaluate the extracts’' antimicrobial and cytotoxic activity. The extraction efficiency was expressed by the total phenolic and total flavonoid content and antioxidant activity (DPPH, IC₅₀, and ORAC) using conventional, ultrasound, and microwave-assisted extraction. The highest bioactive compound content was achieved using 5 min at 60 °C for total phenolic content (214.98 mg GAE g⁻¹), total flavonoid content (22.90 mg EQ g⁻¹), DPPH (45.98 μmol TEAC g⁻¹), inhibitory capacity (0.80 mg mL⁻¹), and ORAC (167.25 μmol Trolox g⁻¹) using ultrasonic extraction, and the extract inhibited the growth of all microorganisms tested. Thirteen chemical compounds were determined by ESI-ToF-MS, confirming the high phytochemical capacity of the extract. Lastly, the Inga extract showed no cytotoxicity at the concentrations used.     

Impact of pulsed electric field pretreatment on yield and quality of lipid extracted from cephalothorax of Pacific white shrimp (Litopenaeus vannamei) by ultrasound-assisted process

Pacific white shrimp cephalothorax was subjected to pulsed electric field (PEF) pretreatment at different electric field strengths (4, 8, 12 and 16 kV cm⁻¹) and pulse numbers (120, 160, 200 and 240) to enhance the extraction yield of lipids. PEF-treated samples were subsequently subjected to lipid extraction using ultrasound-assisted extraction (UAE) process at ultrasound amplitude of 80% for 25 min in continuous mode. PEF-pretreated samples subjected to UAE rendered the highest lipid yield (30.34 g 100 g⁻¹ solids). PEF pretreatment resulted in reduced lipid oxidation as evidenced by the decreases in peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Lipids from PEF-pretreated samples extracted using UAE had higher content of PUFAs and carotenoids, including astaxanthin, astaxanthin monoester, astaxanthin diester, canthaxanthin and β-carotene. Overall, PEF pretreatment helped in enhancing the extraction yield of lipids and carotenoids from shrimp cephalothorax and reduce lipid oxidation to some extent.     

Extract of Salicornia europaea in fresh pasta to enhance phenolic compounds and antioxidant activity

Extract from Salicornia europaea was added to durum wheat fresh pasta. Sensory properties, cooking quality, microbiological stability, content in bioactive compounds and antioxidant activity, before and after pasta digestion were studied. The extract was obtained by ultrasound-assisted extraction. From the technological point of view the extract did not affect pasta dough and the cooking parameters and sensory properties of the enriched samples were found similar to the control pasta. No antimicrobial effect was exerted by the extract. From the chemical point of view interesting findings were recorded for pasta before and after digestion. Specifically, data of bioaccessible fraction of digested sample showed a significantly higher amount of total phenols and flavonoid content (11.52 mg gallic acid g⁻¹ and 0.55 mg quercetin g⁻¹ respectively) than digested control pasta (9.54 mg gallic acid g⁻¹ and 0.23 mg quercetin g⁻¹ respectively). The antioxidant activity of enriched sample also increased compared to the control pasta (6.20 vs. 2.50 μmoles FeSO₄ g⁻¹).     

Pulsed electric fields- and ultrasound-assisted green extraction of valuable compounds from Origanum vulgare L. and Thymus serpyllum L.

This work compared the effects of pulsed electric fields (PEF) and ultrasound (US) technologies on the extent of cell disintegration of two Mediterranean herb tissues (Origanum vulgare L., Thymus serpyllum L.), as well as on the extractability of phenolic compounds during the subsequent hydroalcoholic extraction (0%–50% ethanol in water, v/v) for up to 4 h. The rate of phenolic compounds extraction decreased with time and was predicted rather satisfactorily (R² = 0.898–0.989) by the Peleg’s model. The application of either PEF or US treatment prior to solid–liquid extraction (SLE) has the potential to reduce duration and concentration of ethanol to achieve the same recovery yield of phenolic compounds. Under optimised PEF (3 kV cm⁻¹, 10 kJ kg⁻¹) and US (400 W, 20 min) treatment conditions, the extracts obtained from either PEF or US pretreated herb samples showed higher total phenolic yield (36% on average) and antioxidant activity (FRAP) (36% on average) as compared to the control extraction, especially when 25% ethanol was used as a solvent. GC/MS analyses revealed no evidence of degradation of individual phenolics due to either PEF or US application.     

Microwave and ultrasound assisted extraction of phytocompounds from black jamun pulp: Kinetic and thermodynamics characteristics

The present study focuses on the extraction of phenolic compounds, anthocyanin and antioxidants from black jamun pulp by microwave and ultrasound assisted extraction process. The microwave-assisted extraction was carried out for 240 s at microwave power level of 100–400 W. The yield of total anthocyanin and total phenolic content in the microwave assisted extraction process at 400 W power level after an extraction period of 240 s was 8.197 mg of C3G g⁻¹ and 37.671 40.632 mg GAE g⁻¹, respectively. The ultrasound assisted extraction was performed at temperatures of 40, 50, 60, and 70 °C for 150 min. In the ultrasound assisted extraction at a sonication temperature of 70 °C, the yield of anthocyanin was 8.525 mg of C3G g⁻¹, while the yield of the phenolic compound was 47.331 mg GAE g⁻¹. The pseudo-second order model was found to be the most suitable model to represent the extraction kinetics of anthocyanin, phenolic compounds, and antioxidant activity of black jamun pulp. The effective diffusion coefficient for ultrasound assisted extraction of phenolic components, anthocyanin, and antioxidant activity in the temperature range of 40-70 °C was 5.704× 10⁻¹²–10.515 10⁻¹², 2.485× 10⁻¹² -8.507× 10⁻¹², and 2.061× 10⁻¹²–11.977 × 10⁻¹² m².s⁻¹ respectively. The negative Gibbs free energy change values for extraction of phenolic compounds and anthocyanin specified that the reaction was feasible and spontaneous. Thermodynamic parameters such as positive enthalpy change and positive entropy change indicated that the ultrasound assisted extraction process was endothermic and irreversible in nature.     

Preparation,antioxidant activity and protective effect of coconut testa oil extraction on oxidative damage to human serum albumin

Extraction, physicochemical properties and fatty acid composition analysis of coconut testa oil (CTO), antioxidant activity and the protective effect on oxidative damage to human serum albumin (HSA) of coconut testa oil extract (CTOE) were investigated. Results showed that the optimal extract condition of CTO was B₃A₂C₂ (temperature of 60 °C, material‐to‐solvent of 1:4 g mL^?1 and extraction time of 3 h) with the maximum oil yield (76.83 ± 0.53%). The obtained CTO was nondrying oil with iodine value of 14.69 g per 100 g, and lauric acid was the main component of 42.28%. Hydrogen peroxide scavenging activity of CTOE can reach to 49.81% at 2.5 mg mL^?1, while antioxidant activity (AA) on the oxidation of linoleic acid dropped from 56.82% to 31.70% during the first 80 min. CTOE could prevent HSA from oxidative damage induced by hydrogen peroxide via inhibiting the formation of protein carbonyl and increase of hydroperoxides content effectively. Total phenolic content was 68 mg g^?1, and the epicatechin and catechin were 2.74 and 2.26 mg g^?1 in its phenolic compositions, respectively. These all suggested CTO and CTOE might be new worthy exploiting functional sources.     

Effects of high pressure on biochemical properties and structure of myofibrillar protein from Tegillarca granosa

The effects of high-pressure (HP) treatment parameters (300 MPa for 5 min, 350 MPa for 3 or 5 min and 400 MPa for 1 min) on the biochemical properties and structure of myofibrillar protein (MP) from Tegillarca granosa were investigated. The results showed that HP significantly affected the biochemical properties of MP. Under the HP treatment at 400 MPa for 1 min, the MP extraction yield was reduced from 32.21 to 18.34 mg g⁻¹, and its surface hydrophobicity was increased from 89.29 to 104.69 µg. Ca²⁺-ATPase activity of MP decreased from 0.019 to 0.011 µmol (pi) mg⁻¹ (pro) min⁻¹, and both total and reactive sulfhydryl contents significantly declined. Furthermore, HP caused MP to undergo conformational changes. This study provides a reference data for the processing of T. granosa using HP treatment.     

Enzymatic extraction of fucoxanthin from brown seaweeds

Brown seaweeds contain a number of bioactive compounds. The xanthophyll, fucoxanthin, has in vivo efficacy against disorders such as type 2 diabetes, obesity and cancer. Organic solvents are traditionally employed to extract fucoxanthin, but carry a toxic chemical and environmental burden. The aim of this study was to optimise a fucoxanthin extraction method using enzymes, water, low‐temperature dehydration and mechanical blending, to produce yields comparable to those achieved with an organic solvent (acetone). Response surface methodology was applied, using Fucus vesiculosus as a model species. A fucoxanthin yield of 0.657 mg g^?1 (dry mass) was obtained from F. vesiculosus blade using the enzymatic method, equivalent to 94% of the acetone‐extracted yield. Optimum extraction parameters were determined to be enzyme‐to‐water ratio 0.52%, seaweed‐to‐water ratio 5.37% and enzyme incubation time 3.05 h. These findings may be applied to the development of value‐added nutraceutical products from seaweed.     

Potential of bagasse obtained using hydrothermal liquefaction pre-treatment as a natural emulsifier

Bagasse, a by-product from raw sugar factories, is conventionally burned for energy production. In this study, bagasse extracts from hydrothermal liquefaction (HTL) treatment (160 °C, 1 MPa and 30 min) with a carbohydrate content of 510.3 mg g⁻¹ and 0.5 mg g⁻¹ of total phenols were applied as emulsifiers in oil-in-water (O/W) emulsions. Bagasse extracts from HTL (0.5–4 wt%) lowered the interfacial tension between oil–water interphase from 19.8 to 14.0 mN m⁻¹, owing possibly to the surface-active hydrophilic carbohydrate-hydrophobic lignin complexes in the extracts (lignin content: 7.1% w/w). Emulsions stabilised by bagasse extracts from HTL with average droplet size, d_av of 0.79 μm were comparable with gum arabic (GA), d_av of 2.24 μm after 11 days at 25 °C. Bagasse extracts containing biopolymers have the potential for industrial applications involving emulsion systems; therefore, HTL treatment of bagasse without any solvents can be regarded as an effective tool for producing natural emulsifiers.     

Bioactive compounds and antioxidant activities of Brazilian hop (Humulus lupulus L.) extracts

Bioactive compounds from Brazilian hop (Humulus lupulus L.) cultivars were extracted by ultrasound and their phenolic profile compared with commercial hop from the USA. The most effective extraction conditions (solution of ethanol 49%, at 52 °C and a solid/liquid ratio of 1 g per 34 mL) for the total phenolic compounds (TPC) were determined using a Central Composite Rotatable Design. The Brazilian hop showed higher content of TPC (33.93 ± 0.67 mg GAE g⁻¹), total flavonoids (54.47 ± 0.10 mg QE g⁻¹) and higher antioxidant activity (ABTS: EC₅₀ 21.29 ± 1.36 μL mL⁻¹; DPPH: EC₅₀ 3.91 ± 0.17 μL mL⁻¹) when compared with the USA hop. The main phenolic compounds present in the extracts were the flavonoids isoquercitrin and quercetin. The antioxidant properties of the Brazilian hop extract had not been reported yet in the literature for this raw material, thus showing potential to be incorporated in polymeric films used as active packaging.     

The effect of simulated digestion on the composition of phenolic compounds and antioxidant activities in lychee pulp of different cultivars

Simulated gastric fluid (SGF) and intestinal fluid (SIF) digestion were used to evaluate the effects of digestion on the composition of phenolic compounds and antioxidant capacities of the pulp of six lychee cultivars. Caffeic acid, ferulic acid, procyanidin B2, epicatechin, A-type procyanidin trimer, procyanidin A2, quercetin-3-rutinose-7-rhamnoside, rutin and isoquercitrin were quantified using HPLC-DAD. Lychee pulp had high concentrations of procyanidin B2 (0.30~15.53 mg g⁻¹), procyanidin A2 (0.29~0.52 mg g⁻¹) and quercetin-3-rutinose-7-rhamnoside (0.16~0.45 mg g⁻¹). SGF and SIF Digestion, which significantly decreased the concentration of procyanidin B2, epicatechin and quercetin-3-rutinose-7-rhamnoside. But observably increased the concentration of procyanidin A2. Compared with deionized water treatment (DW), the total phenolic content (TPC) and total flavonoid content (TFC) of different lychee pulps significantly increased after SGF and SIF digestion. After SGF digestion, the ferric ion reducing antioxidant power (FRAP) of lychee pulps increased while the ABTS+ free radical scavenging ability (ABTS) had a slight decline. This shows that simulated digestion improves the bioactive component and antioxidant activity of different varieties of lychee pulp.     

Rapidly colorimetric detection of caffeine in beverages by silver nanoparticle sensors coupled with magnetic molecularly imprinted polymeric microspheres

Excessively intaking caffeine can harm human health, and it is imperative to develop a rapid method to identify caffeine for food safety. The magnetic molecularly imprinted polymeric microspheres (MMIPs) were prepared to pretreat samples before silver nanoparticles (AgNPs) colorimetric detection of caffeine. Using Fe₃O₄ as supporting core, mesoporous SiO₂ as intermediate shell, α-methylacrylic acid as functional monomer and caffeine as template, the prepared MMIPs were characterised by transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer. Adsorption process followed Langmuir adsorption isotherm with maximum adsorption capacity at 38.8 mg g⁻¹ under 298 K. The MMIPs extract caffeine from beverages, then the AgNPs colorimetric method rapidly screened and semi-quantified caffeine ≥5 mg L⁻¹ by naked eye, and accurately quantified caffeine ranging 0.1–5 mg L⁻¹ by UV-vis spectroscopy at 393 nm, which were consistent with HPLC analytical results. Thus, this method might be used to rapidly enrich and analyse caffeine in beverages.     

Effects of plasma-activated water on microbial growth and storage quality of fresh-cut apple

Fresh-cut ‘Fuji’ apples were immersed for 5 min in plasma-activated water (PAW) generated, by plasma generated with sinusoidal voltages at 7.0 kHz with amplitudes of 6 kV, 8 kV, and 10 kV, designated PAW-6, PAW-8, and PAW-10, respectively. The control group was soaked in distilled water for 5 min instead of PAW. The results indicated that the growth of bacteria, molds, and yeasts was inhibited by PAW treatments during storage at 4 ± 1 °C, especially the microbial inactivation with PAW-8, which was the most efficient. PAW-8 reduced the microbial counts by 1.05 log₁₀CFU g⁻¹, 0.64 log₁₀CFU g⁻¹, 1.04 log₁₀CFU g⁻¹ and 0.86 log₁₀CFU g⁻¹ for aerobic bacteria (aerobic plate counts), molds, yeasts and coliforms on day 12, respectively. In addition, the bacterial counts of fresh-cut apples treated with PAW were <5 log₁₀CFU g⁻¹, which did not exceed to the existing China Shanghai local standard (DB 31/2012–2013) during 12 days of storage. PAW treatments reduced superficial browning of fresh-cut apples without affecting their firmness and titratable acidity. In addition, no significant change was observed in antioxidant content and radical scavenging activity between the PAW-treated and control groups. It is suggested that PAW is a promising method for preservation of fresh-cut fruits and vegetables, which is usually beneficial to the quality maintenance of fresh-cut fruits and vegetables during storage.     

Dynamic changes in flavonol glycosides during production of green,yellow, white,oolong and black teas from Camellia sinensis L. (cv. Fudingdabaicha)

Flavonol glycosides with low thresholds are important flavour substances in tea leaves. This study monitored the dynamic changes in flavonol glycosides during the production of different teas. The fresh leaves of cv. Fudingdabaicha with 15.77 mg g⁻¹ of total flavonol glycosides (TFG) were respectively processed into green, yellow, white, oolong and black teas. A reduction of TFG was observed for different teas, amongst which black tea contained the lowest level of TFG (9.83 mg g⁻¹), followed by oolong tea (11.96 mg g⁻¹), while green, yellow and white teas contained similar levels of TFG (~13.70 mg g⁻¹). Fixation was crucial to maintain the stability of flavonol glycosides due to its inactivation effect on enzymes at high temperature. Principal component analysis results indicated that flavonol glycosides were vulnerable to fermentation, and the stabilities of flavonol glycosides were related with aglycone and glycoside moiety.     

Combined densification and pulsed electric field treatment for selective polyphenols recovery from fermented grape pomace

The aim of this study is to assess a new process for the valorization of fermented grape pomace using pulsed electric fields (PEF). The combination of densification and PEF treatment was applied on grape pomace of low relative humidity, without any addition of conductive liquid. The kinetics of extraction and the composition of polyphenols were evaluated throughout the subsequent hydro-alcoholic extraction at different temperatures.Optimal parameters of PEF treatment (field strength E = 1.2 kV·cm^− 1; energy input W = 18 kJ·kg^− 1; density ρ = 1.0 g·cm^− 3) increased the content of total polyphenols regardless of the temperature of extraction. The ratio of total anthocyanins to total flavan-3-ols at 20 °C was equal to 7.1 and 9.0 for control and PEF treated modalities, respectively. These results demonstrate the selective nature of PEF treatment in anthocyanin extraction, and thus reveal new possibilities to produce extracts with different biochemical compositions.Industrial relevanceThis study examines the feasibility of densification combined with PEF pre-treatment of relatively low humidity grape pomace for the enhancement of bioactive compounds extraction. The concentration of total phenolic compounds obtained after PEF treatment showed that the use of this technique is relevant for an industrial use, since solvent amount and extraction time can be reduced. Moreover, the selective nature of PEF opens the opportunity to produce extracts of different biochemical compositions. This process is an alternative to conventional pre-treatments of raw material (e.g. dehydration and grinding), which have impacts on product quality and are more energy consuming.     

Selective separation and characterisation of dual ACE and DPP-IV inhibitory peptides from rainbow trout (Oncorhynchus mykiss) protein hydrolysates

Microwave pretreatment and hydrolysis were applied to rainbow trout (Oncorhynchus mykiss) by-products to produce bioactive peptides with dual in vitro angiotensin-I converting enzyme (ACE) and dipeptidyl-peptidase IV (DPP-IV) inhibitory activities. Peptides were fractionated using the single step electrodialysis with ultrafiltration membrane (EDUF). Concentration of cationic peptides (CP) increased in the recovery solution, reaching 125 μg mL⁻¹ after a 4-h treatment with migration rate of 15.68 ± 2.98 g m⁻² h. CP fractions displayed ACE and DPP-IV I inhibitory properties, with IC₅₀ values of 0.0036 mg mL⁻¹ and 1.23 mg mL⁻¹ respectively. The bioactivity was attributed to the low molecular weight peptides (300–500 Da) recovered. CP exhibited non-competitive inhibition patterns for ACE and DPP-IV, which were dose dependent. These results showed that bioactive peptides can successfully be separated from complex hydrolysate mixtures by EDUF. The fractionated peptides can serve as potential functional food ingredients or nutraceuticals for the management of hypertension and diabetes.     

Pulsed electric field treatment enhances lipid bioaccessibility while preserving oxidative stability in Chlorella vulgaris

There is growing demand for gentle technologies to improve the lipid bioaccessibility (BA) of Chlorella vulgaris biomass while preserving cell integrity and therefore oxidative stability. Pulsed electric field treatment (PEF, 5 μs at 20 kV cm⁻¹, 31.8 kJ kg⁻¹_sus) led to an enhancement in lipid BA from 4–7.8% (untreated) to 18.7–20.9%. To reach such a level of BA, incubation in buffer after the treatment (12 h at 25/37 °C, 48 h at 4 °C) was required. As hypothesized, PEF preserved cell integrity, as shown by particle size and scanning electron microscopy analyses, as well as oxidative stability of the biomass over 3 months at 40 °C. Proteome analysis identified four proteins that may be involved in cell wall lytic activity during incubation after PEF. Future work should focus on further understanding the mechanism behind incubation after PEF and studying the potential effect played by endogenous cell wall-degrading enzymes.     

Process optimisation of microwave‐assisted extraction of peony (Paeonia suffruticosa Andr.) seed oil using hexane–ethanol mixture and its characterisation

Ethanol and hexane mixture agent microwave‐assisted extraction (MAE) method was conducted to extract peony (Paeonia suffruticosa Andr.) seed oil (PSO). The aim of the study was to optimise the extraction for both yield and energy consumption in mixture agent MAE. The highest oil yield (34.49%) and lowest unit energy consumption (14 125.4 J g^?1) were obtained under optimum extraction condition: solid‐liquid ratio 0.37 g mL^?1, extraction time 3.72 min, extraction temperature 80.92 °C, ethanol ratio 20.00%. GC–MS results showed that unsaturated fatty acids (UFAs) accounted for 88.60% of total fatty acids in PSO. Moreover, linolenic acid content of 37.35% was the highest UFA and caused PSO to possess good nutrition. PSO in DPPH radical scavenging experiment showed that IC₅₀ value of 28.80 ± 2.13 mg mL^?1 exhibited strong antioxidant property. All experiments proved that mixed solvent MAE is an efficient and promising method to extract PSO. This method can effectively reduce the energy consumption and extraction time.     

Metabolites composition and variation in processing waste of water chestnut

There are fourteen compounds tentatively identified from fresh processing waste of different ripened water chestnut (WC) by using high performance liquid chromatography combined with diode array detector and high resolution mass spectrometer (HPLC-DAD-HRMS). The chromatographic profiles show that most of the chemical components of the peels are similar in various ripening stages but the contents increase significantly during ripening. The most abundant metabolite is chlorogenic acid which increased more than four times and reached 3.046 mg g⁻¹ in the peel of fully ripened WC. The second biggest peak is at retention time 1.82 min. The peak in half ripened WC is a combined compound of sucrose and quinic acid which is probably an intermediate product of the cell walls of WC. It is mainly a trisaccharide in near ripened WC, and mainly a tetrasaccharide in fully ripened WC. Peel of fully ripened WC contains all the above compounds, stachyose, coumaroylquinic acid, feruloylquinic acid, feruloylmalic acid, 6,7,3′,4′-tetrahydroxyaurone, 3,3′,4′,5,7,8-hexahydroxyflavan, tectorigenin, luteolin, apigenin, rhamnocitrin and dihydrokaempferide. All the above metabolites except the last six flavonoids and chlorogenic acid are the first time reported from WC. Bud of WC contains the same metabolites as the peel. Puchiin contains much less metabolites and the content of chlorogenic acid is only 0.013 mg g⁻¹. Most of the metabolites are bioactive compounds associated with the health function of WC. Because that peel and bud of the fully ripened WC not only possess 94.44% of the total processing waste but also contain all the bioactive compounds, they have great potential for metabolites utilisation.     

Evaluation of flavonoid and polyphenol constituents in mulberry leaves using HPLC fingerprint analysis

The mulberry leaf is a promising dietary source of antioxidants due to its high levels of beneficial compounds. To further examine its antioxidant properties, twelve batches of authenticated mulberry leaf, with total flavonoid contents (TFC) ranging from 24.34 mg g⁻¹ DW to 58.42 mg g⁻¹ DW and total polyphenol content (TPC) ranging from 11.49 mg g⁻¹ DW to 30.03 mg g⁻¹ DW, were investigated. According to Spearman’s coefficient, antioxidant activities, including the DPPH radical scavenging assay and the ferric reducing antioxidant power (FRAP), were positively correlated with TFC and TPC. The HPLC-DAD analysis results identified the characteristic fingerprint peaks in mulberry leaves as chlorogenic acid, rutin, quercetin 3-O-glucoside and kaempferol 3-O-glucoside, all of which directly contribute to the antioxidant capacity of mulberry leaves. Notably, young mulberry leaves showed higher antioxidant capacity than those of mature leaves. These promising results help create a compelling case for future development of mulberry leaf products.