Microencapsulation of ultrasound-assisted phenolic extracts of sugar maple leaves: Characterization, in vitro gastrointestinal digestion, and storage stability.

Sugar maple leaves (SML), usually considered residue plant biomass and discarded accordingly, contain a considerable amount of phenolic antioxidants. In this study, SML phenolics were extracted employing both advanced (homogenization pretreated ultrasound-assisted extraction) and conventional (maceration) methods followed by their encapsulation by freeze drying and spray drying using a combination of maltodextrin and gum arabic as coating agents. Detailed physicochemical analyses revealed that the encapsulated microparticles had high solubility (>90 %) and encapsulation efficiency (>95 %), acceptable thermal stability with good handling properties. Phenolic compounds were completely released from microparticles during simulated gastric conditions. The microparticles influenced the bioaccessibility of more than 43 % of the phenolic fraction in the intestinal phase. The antioxidant capacity of the microparticles was preserved during storage. These findings suggest the effectiveness of the microencapsulation process for producing high quality microparticles of SML phenolic extracts and the possibility of their use in the food, nutraceutical, bio-pharmaceutical sectors.

Phenolic mapping and associated antioxidant activities through the annual growth cycle of sugar maple leaves.

Concentrations of antioxidant components (analyzed by HPLC-UV) and antioxidant attributes (assayed by radical scavenging and non-radical redox potential methods) of sugar maple leaves (SML) from different harvesting times were investigated. Moreover, measurements of colorimetry, SEM, and FTIR spectroscopy-based characterization of leaves composition, throughout the growth cycle, were performed. Results showed that the antioxidant activities of SML are strongly correlated with phenolic contents and significantly (p < 0.05) varied with harvesting time where minimum amount of total phenolics (105.67 ± 13.16 mg GAE/g DM) and total flavonoids (3.27 ± 0.26 mg CTE/g DM) were found to be concentrated in Fall leaves. The absorption bands obtained from FTIR spectra revealed the presence of functional groups that have great significance towards the antioxidant activity of SML. Principal component analysis revealed that biosynthesis of maximum phenolic compounds in SML mostly occurs during the leaf expansion and growth phases. The obtained data provided a better understanding towards the effect of harvesting time on the phenolic mapping of SML in favor of its valorization into functional food ingredients.

Relationship between Total Antioxidant Capacity, Cannabinoids and Terpenoids in Hops and Cannabis.

Efficient determination of antioxidant activity in medicinal plants may provide added value to extracts. The effects of postharvest pre-freezing and drying [microwave-assisted hot air (MAHD) and freeze drying] on hops and cannabis were evaluated to determine the relationship between antioxidant activity and secondary metabolites. The 2,2-diphenyl-1-picrylhydrazine (DPPH) reduction and ferric reducing ability of power (FRAP) assays were assessed for suitability in estimating the antioxidant activity of extracted hops and cannabis inflorescences and correlation with cannabinoid and terpene content. Antioxidant activity in extracts obtained from fresh, undried samples amounted to 3.6 Trolox equivalent antioxidant activity (TEAC) (M) dry matter-1 and 2.32 FRAP (M) dry matter-1 for hops, in addition to 2.29 TEAC (M) dry matter-1 and 0.25 FRAP (M) dry matter-1 for cannabis. Pre-freezing significantly increased antioxidant values by 13% (DPPH) and 29.9% (FRAP) for hops, and by 7.7% (DPPH) and 19.4% (FRAP) for cannabis. ANOVA analyses showed a significant (p < 0.05) increase in total THC (24.2) and THCA (27.2) concentrations (g 100 g dry matter-1) in pre-frozen, undried samples compared to fresh, undried samples. Freeze-drying and MAHD significantly (p < 0.05) reduced antioxidant activity in hops by 79% and 80.2% [DPPH], respectively and 70.1% and 70.4% [FRAP], respectively, when compared to antioxidant activity in extracts obtained from pre-frozen, undried hops. DPPH assay showed that both freeze-drying and MAHD significantly (p < 0.05) reduced the antioxidant activity of cannabis by 60.5% compared to the pre-frozen samples although, there was no significant (p < 0.05) reduction in the antioxidant activity using the FRAP method. Greater THC content was measured in MAHD-samples when compared to fresh, undried (64.7%) and pre-frozen, undried (57%), likely because of decarboxylation. Both drying systems showed a significant loss in total terpene concentration, yet freeze-drying has a higher metabolite retention compared to MAHD. These results may prove useful for future experiments investigating antioxidant activity and added value to cannabis and hops.

Ultrasound-Assisted Extraction of Antioxidants from Melastoma malabathricum Linn.: Modeling and Optimization Using Box-Behnken Design.

This study presents modeling and optimization of ultrasound-assisted extraction (UAE) of Melastoma malabathricum with the objective of evaluating its phytochemical properties. This one-factor-at-a-time (OFAT) procedure was conducted to screen for optimization variables whose domains included extraction temperature (XET), ultrasonic time (XUT), solvent concentration (XSC), and sample-to-liquid ratio (XSLR). Response surface methodology (RSM) coupled with Box-Behnken design (BBD) was applied to establish optimum conditions for maximum antioxidant extraction. Modeling and optimization conditions of UAE at 37 kHz, XET 32 °C for XUT 16 min and dissolved in an XSC 70% ethanol concentration at a XSLR 1:10 ratio yielded scavenging effects on 2,2-diphenyl-1-picryl-hydrazyl (DPPH) at 96% ± 1.48 and recorded values of total phenolic content (TPC) and total flavonoid content (TFC) at 803.456 ± 32.48 mg GAE (gallic acid equivalents)/g, and 102.972 ± 2.51 mg QE (quercetin equivalents)/g, respectively. The presence of high flavonoid compounds was verified using TWIMS-QTOFMS. Chromatic evaluation of phytochemicals using gas chromatography-mass spectrometry (GC-MS) revealed the presence of 14 phytocompounds widely documented to play significant roles in human health. This study provides a comparative evaluation with other studies and may be used for validation of the species' potential for its much-acclaimed medicinal and cosmeceutical uses.

Green extraction and characterization of leaves phenolic compounds: a comprehensive review.

Although containing significant levels of phenolic compounds (PCs), leaves biomass coming from either forest, agriculture, or the processing industry are considered as waste, which upon disposal, brings in environmental issues. As the demand for PCs in functional food, pharmaceutical, nutraceutical and cosmetic sector is escalating day by day, recovering PCs from leaves biomass would solve both the waste disposal problem while ensuring a valuable "societal health" ingredient thus highly contributing to a sustainable food chain from both economic and environmental perspectives. In our search for environmentally benign, efficient, and cost-cutting techniques for the extraction of PCs, green extraction (GE) is presenting itself as the best option in modern industrial processing. This current review aims to highlight the recent progress, constraints, legislative framework, and future directions in GE and characterization of PCs from leaves, concentrating particularly on five plant species (tea, moringa, stevia, sea buckthorn, and pistacia) based on the screened journals that precisely showed improvements in extraction efficiency along with maintaining extract quality. This overview will serve researchers and relevant industries engaged in the development of suitable techniques for the extraction of PCs with increasing yield.

Microwave- and Ultrasound-Assisted Extraction of Cannabinoids and Terpenes from Cannabis Using Response Surface Methodology.

Limited studies have explored different extraction techniques that improve cannabis extraction with scale-up potential. Ultrasound-assisted and microwave-assisted extraction were evaluated to maximize the yield and concentration of cannabinoids and terpenes. A central composite rotatable design was used to optimize independent factors (sample-to-solvent ratio, extraction time, extraction temperature, and duty cycle). The optimal conditions for ultrasound- and microwave-assisted extraction were the sample-to-solvent ratios of 1:15 and 1:14.4, respectively, for 30 min at 60 °C. Ultrasound-assisted extraction yielded 14.4% and 14.2% more oil and terpenes, respectively, compared with microwave-assisted extracts. Ultrasound-assisted extraction increased cannabinoid concentration from 13.2−39.2%. Considering reference ground samples, tetrahydrocannabinolic acid increased from 17.9 (g 100 g dry matter−1) to 28.5 and 20 with extraction efficiencies of 159.2% and 111.4% for ultrasound-assisted and microwave-assisted extraction, respectively. Principal component analyses indicate that the first two principal components accounted for 96.6% of the total variance (PC1 = 93.2% and PC2 = 3.4%) for ultrasound-assisted extraction and 92.4% of the total variance (PC1 = 85.4% and PC2 = 7%) for microwave-assisted extraction. Sample-to-solvent ratios significantly (p < 0.05) influenced the secondary metabolite profiles and yields for ultrasound-assisted extracts, but not microwave-assisted extracts.

Influence of plasma activated water treatment on enzyme activity and quality of fresh-cut apples.

Plasma activated water (PAW) is a new approach to disinfecting surfaces including fresh-cut foods while maintaining their quality attributes. The aim of this study was to evaluate the effect of PAW on enzyme activity, microbial and physicochemical quality of fresh-cut apples. PAW was produced at different production activation times of 10 min, 20 min, 30 min, 45 min and 60 min and the fresh-cut apple slices were washed with PAW for 5 min and stored at 4 °C for 12 days. Results showed that PAW treatments reduced the polyphenol oxidase activity immediately after treatment and the lowest activity was recorded in PAW-20 min (5.10 ± 0.16 U/g FW) after 12 days. Conversely, peroxidase activity of the samples increased immediately after PAW treatment and the samples treated with PAW activated for 30 min had the lowest peroxidase activity at the end of 12 days of storage. No significant changes in the total phenolic content and FRAP antioxidant activity of the fresh-cut apple samples after PAW treatments. The results from firmness, membrane permeability, respiration rate and microstructural imaging showed that at higher PAW activation times (45 min and 60 min) had adverse effects on the quality of fresh-cut apples. Significant reductions in the total aerobic bacteria and total yeast and molds were observed in all PAW treatments except PAW activated for 10 min. The results suggests that plasma activated water could maintain the quality of the fresh-cut apples during storage for plasma activation times of 20 min and 30 min for up to 12 days of storage.

Microwave-assisted alkaline extraction of galactan-rich rhamnogalacturonan I from potato cell wall by-product.

Galactan-rich rhamnogalacturonan I (RG I), exhibiting promising health benefits, is the most abundant polysaccharide in potato pulp by-product. In the present study, the microwave-assisted alkaline extraction of galactan-rich RG I was investigated. Solid/liquid ratio was identified as the most significant parameter affecting linearly yield and galactose/rhamnose contents. Microwave power and solid/liquid ratio exhibited a significant adverse interactive effect on the yield. Galactose content of extracted polysaccharides can be modulated by compromising between KOH concentration and extraction time, which exhibited adverse interaction. Optimum conditions were identified using the established predicted models and consisted of treatment of potato cell wall at solid/liquid ratio of 2.9% (w/v) with 1.5M KOH under microwave power of 36.0 W for 2.0 min. Yield of intact galactan-rich RG I of 21.6% and productivity of 192.0 g/Lh were achieved. The functional properties of RG I-rich polysaccharides were comparable or superior to potato galactan and oranges homogalacturonan.

Fatty acid profiling of the seed oils of some varieties of field peas (Pisum sativum) by RP-LC/ESI-MS/MS: towards the development of an oilseed pea.

Reversed-phase liquid chromatography coupled to negative-ion electrospray tandem mass spectrometry (RP-LC/ESI-MS/MS) was used to study the fatty acid profile from the oil of harvested field pea (Pisum sativum) varieties as part of a research project to develop this legume as a commercial oilseed for Canada. The seed oils from pea samples contained palmitic and stearic acids as major saturated fatty acids. Oleic, linoleic and linolenic acids were the major unsaturated fatty acids found. Small percentages of other long chain fatty acids were also detected. This profile suggests that the species of field pea investigated might have the potential to be used as raw materials to develop a future new oilseed crop for the food industry. Fatty acid extracts did not require further manipulation before final analysis by RP-LC/ESI-MS/MS, indicating the utility and relative simplicity of this technique for future screening studies.

Microwave-assisted extraction of phenolic antioxidants from potato peels.

A response surface method was used to optimize the microwave-assisted extraction parameters such as extraction time (t) (min), solvent (methanol) concentration (S) (v/v) and microwave power level (MP) for extraction of antioxidants from potato peels. Max. total phenolics content of 3.94 mg g⁻¹ dry weight (dw) was obtained at S of 67.33%, t of 15 min and a MP of 14.67%. For ascorbic acid (1.44 mg g⁻¹ dw), caffeic acid (1.33 mg g⁻¹ dw), ferulic acid (0.50 mg g⁻¹ dw) max contents were obtained at S of 100%, t of 15 min, and MP of 10%, while the max chlorogenic acid content (1.35 mg g⁻¹ dw) was obtained at S of 100%, t of 5 min, and MP of 10%. The radical scavenging activity of the extract was evaluated by using the DPPH assay and optimum antioxidant activity was obtained at S of 100%, t of 5 min, and MP of 10%.