Grape skin extracts: Natural antioxidants in an oil‐in‐water emulsion.
Summary
Grape (Kyoho) skin, used to retard lipid oxidation in edible oil foods, was investigated to reduce lipid oxidation in an ...oil‐in‐water (O/W) emulsion during 20 day of storage. The antioxidant efficacy of Kyoho skin extracts in O/W emulsions was determined by the measurement of secondary oxidation products. Moreover, principal component analysis (PCA) was conducted to determine similarities between emulsions treated with or without Kyoho skin extracts and standards. The data revealed that Kyoho skin extracts exhibited >93% inhibition and reported a similar p‐anisidine (4.30–20.71) and TBARS (6.08–11.15 mg MDA L−1) values over the standards during 20 day of storage. PCA (PCs 1 (51.83%) and 2 (18.85%)) demonstrated a similarity in the contribution of Kyoho skin extracts over the synthetic antioxidants in O/W emulsion. Overall, these findings highlighted the possibility of using Kyoho skin extracts as natural antioxidants to decrease oxidative rancidity in foods.
Summary
Grapes are rich sources of polyphenols and widely used in food fortification due to their health‐promoting properties. Previous studies have provided systematic strategies on foods fortified ...with grape polyphenols; however, until now, very little is known about grape polyphenol market, fortification and their health food regulations. It is, therefore, necessary to make a comprehensive overview of grape extract polyphenols and their fortification in functional foods. Hence, we reviewed the grape polyphenol market, fortification, health food market scenario and functional food regulations. The global grape polyphenol market is expected to rise 946.90 million USD by 2023 with its own trademark as polyphenol‐fortified functional foods. This is ultimately due to acceptability, extensive use, marketing of polyphenol‐fortified functional foods and their favourable food regulations. The future perspective on grape polyphenols research should be focused on extraction of polyphenols from grape waste and their fortification in functional foods.
Functional food properties, fortification potential, and market value of grape polyphenols.
Grape skin, seed and flesh, a potential source of bioactive compounds, were investigated to discriminate Kyoho skin, seed and flesh antioxidant activities by solvent extraction using chemometrics, ...including multivariate, discriminant analysis (DA) and hierarchical cluster analysis (HCA). Multivariate analysis (Wilk's Λ = 0.02 × 10‐4, P < 0.01) explained the discrimination behaviour of phenolics and antioxidants by different solvents. Moreover, DA with three discrimination functions (DFs) and HCA with three well‐defined clusters (clusters 1 to 3) further demonstrated the differences and/or similarities among the solvents. Solvent I (75% ethanol: water) exhibited the different extraction process over the solvents IV (water) and III (acetone: water). Quercetin (39.25 mg kg−1), epicatechin (53.08 mg kg−1) and gallocatechin gallate (1.28 mg kg−1) were the major phenolic compounds in Kyoho skin, seed and flesh extracts, respectively. These further confirmed the chemometric approach that could be used to discriminate solvents. Therefore, these findings suggested the application of chemometrics in extraction studies to understand the role of solvents and high recovery of grape bioactive compounds.
Solvent extraction and discrimination behaviour of Kyoho skin, seed and flesh antioxidant activities using advanced chemometrics.
Multivariate statistical techniques were used to differentiate two popularly consumed grape cultivars in Taiwan, Kyoho (Vitis labruscana) and American wild bunch (Vitis aestivalis), based on their ...phenolic content and antioxidant properties. Total phenol and flavonoid contents, and polyphenolic profile were estimated by the Folin‐Ciocalteu, colorimetric method, and ultra performance liquid chromatography, respectively. Antioxidant activities were determined by 2,2 diphenyl‐1‐picrylhydrazyl, 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) scavenging activity, ferric reducing antioxidant power (FRAP), nitric oxide scavenging activity (NOSA), hydrogen peroxide scavenging activity, and total antioxidant activity methods. Data were processed using multivariate analysis of variance, discriminant analysis (DA), principal component analysis (PCA), and cluster analysis. Variations in polyphenolic compositions were attributed to higher TFC (3.42 mg QE/g), ABTS• (79.08%), NOSA (27.62%), total antioxidant (77.91%), and superoxide (46.55%) radical scavenging activities of Kyoho grape extracts; and higher inhibition capacity by DPPH• (97.26%), FRAP (4.66 mM FeSO4/g), and hydrogen peroxide (40.52%) scavenging methods for American wild bunch grape extracts. Two discriminant functions in DA reported the contribution of each phenolic and antioxidant activity in discriminating the cultivars. The results of PCA analysis reported 91.35% of the total variance, which was a suitable approach for evaluating similarities between both cultivars. Statistical analyses confirmed Kyoho and American wild bunch grape extracts differed from each other in terms of polyphenolic composition and antioxidant activities. Therefore, the application of multivariate statistical techniques used in the study provided further understanding on assessment of polyphenols and antioxidant activities of these grape cultivars.
Multivariate statistical techniques including discriminant analysis (DA) and principal component analysis (PCA) was applied to distinguish two grape cultivars (Kyoho and American wild bunch) based on phenolics and antioxidant properties. Variations in polyphenolic composition resulted in significantly different radical scavenging activities of the extracts. The chemometric methods (DA and PCA) confirmed the contribution of polyphenolic composition and antioxidant activities in discriminating the cultivars. Application of chemometric could be effective to identify the contribution of each antioxidant activity of plant extracts.
Potatoes are a source of starch, which is an eco-friendly alternative to petrochemicals in plastic production. Increasing potato production also creates agricultural waste that could be converted to ...potato peel starch (PPS) and developed as films. A response surface method approach was employed to optimize the bioconversion of PPS (2, 4, and 6% w/v) and compared with carboxymethyl cellulose (CMC)-based films. The microstructure analysis of PPSF showed increased thickness, decreased swelling power, water solubility, and vapor permeability, which were linked to increased molecular interactions as a function of PPS increments. However, low-starch PPSF exhibited high transparency, good mechanical properties, and thermal stability (high melting temperature), pliability, and accelerated seawater and soil biodegradation (~90%: 20 and 50 days, respectively). All films exhibited thermal stability at >100 °C and retained similar amorphous characteristics, evidenced by their flexibility, which confirmed the potential use for PPS in packaging perishable and cooled foods.
Probiotic bacteria are usually encapsulated to increase their survival through passage of the simulated gastrointestinal tract (GIT). Four
were freeze-dried and encapsulated with maltodextrin ...(maltodextrin 1.25 g, whey 0.25 g, bacteria 0.5 g, and water 2 mL) and arrowroot starch (arrowroot 1.25 g, whey 0.25 g, bacteria 0.5 g, and water 2 mL). The effects of different coatings were evaluated for their viability in the GIT and yogurt. The findings indicated no significant differences at
> 0.05 in the survival of the encapsulated cells with increased concentrations of arrowroot and maltodextrin. The viability of the encapsulated bacteria was increased in the simulated GIT with high counts of 10
cfu/mL after 30 min stiffening in 1 µm size beads. However, the bead fermented yogurt exhibited insignificant difference on the survivability of the organisms in a simulated GIT after 15 days.
,
,
, and
showed a significant increase of viable cells at
> 0.05 after freeze-drying in comparison with free cells at high bile salt concentrations and low acidity. This study confirmed that arrowroot starch and maltodextrin combinations in encapsulation might be an effective method that could allow viable probiotic bacteria to reach the large intestine.
The antioxidant capacities of Kyoho skin, seed, and flesh extracts were determined using DPPH and ABTS assays and a suitable statistical program was tested for the prediction of EC
values of Kyoho ...skin, seed, and flesh extracts obtained by DPPH and ABTS assays. Statistical programs: OriginPro® version 8, GraphPad Prism® version 7, GraphPad Prism® version 7 five-parameter (5P) logistic model, SigmaPlot® version 14.0, Microsoft Excel® version 2016, interpolation log, and direct interpolation methods were employed to estimate the EC
values. Linear regression and direct interpolation results showed deviations for non-linear models in the prediction of EC
values of grape extracts. The correlation results of grape flesh extracts demonstrated a positive correlation (r = ≥ 0.95) between EC
values of antioxidant assays. Therefore, non-linear methods were appropriate for EC
calculations. These findings have significant implications for selecting an efficient statistical tool to calculate EC
values for DPPH and ABTS assays.
Grape skin (Kyoho: Vitis labruscana), a by-product of processed grapes, was experimentally investigated for its drying behavior at different drying temperatures with five thin layer drying models. ...Moreover, we determined the effect of drying temperature on the bioactive capacity of Kyoho skin. The experimental moisture ratio decreased with increasing drying temperature. The drying process was predicted by mathematical models, such as Page (303.15 K: R2 = 0.9815, 333.15 K: R2 = 0.9685) and two-term (313.15 K: R2 = 0.9639, 323.15 K: R2 = 0.9737) models. Moisture diffusivity (Deff) ranged from 2.87 × 10−8 to 9.82 × 10−8 m2/s, with an activation energy (Ea) of 33.78 ± 1.06 kJ/mol. Total phenolic compounds (0.37 ± 0.04 to 0.23 ± 0.03 mg GAE/g) and antioxidant activities (DPPH• activity of 93.06 to 73.31%) of Kyoho skin were significantly affected by drying temperature. Thus, this study concluded that the drying process decreased the bioactive potential of grape skin; therefore, we recommend that the food processing industry needs to consider drying variables during the processing of grape skin-based value-added products for improved food production.
Seaweeds (
Kappaphycus alvarezii
and
Sargassum duplicatum
) are potentially rich sources of bioactive compounds and functional constituents that are used in food applications. Sun, oven, vacuum, and ...freeze-drying techniques are commonly used seaweed drying techniques and could be classified as cheap (sun and oven) and expensive (vacuum and freeze) drying techniques based on ovens’ market price. Therefore, the study was designed to investigate the effect of cheap (sun and oven) and expensive (vacuum and freeze) drying techniques based on color and antioxidant potential of
K. alvarezii
and
S. duplicatum
using phenolic and antioxidant assays. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed to discriminate the drying techniques by instrumental color analysis. The results revealed that oven-dried seaweed extracts exhibited higher levels of phenolic (0.30 to 0.36 mg GAE g
−1
) and antioxidant potential (3.59 to 79.68%). PCA and HCA discriminated the drying techniques into two well-defined groups/clusters I (oven, vacuum, and freeze-drying) and II (sun drying) and revealed higher ΔE values of sun-dried seaweed samples, which was interpreted as color was preserved using drying techniques of cluster I. Overall, oven, vacuum, and freeze-drying techniques reported similarities in color characteristics and could be an alternate drying technique to preserve the color of seaweed cultivars. Therefore, oven drying technique is recommended due to low cost (compared with vacuum and freeze-drying) and an affordable alternative to sun drying, the preferred technique in fishing communities of low-and-middle-income countries, for the development of seaweed-enriched functional foods.
Studies of renewable polymers have highlighted starch’s role to replace petroleum-based components to produce biodegradable films with plastic-like qualities. In this study, the novelty of taro peel ...starch (TPS) to produce such films using the casting technique is reported for the first time. A response surface method (RSM) approach was employed to optimize different concentrations of TPS (2.5−3.5%, w/w) and glycerol (25−35%, w/w) and investigate their effects on the physico-mechanical and water barrier properties of TPS films. TPS films showed a positive linear effect (p < 0.05) for thickness (0.058−0.088 mm), opacity (1.95−2.67), water vapor permeability (0.06−0.09 g∙m/m2∙kPa∙h), and cubic effect (p < 0.05) for moisture content (0.58−1.57%), which were linked to high starch concentrations when plasticized with glycerol. X-ray diffraction analysis of TPS films depicted “amorphous”-type crystalline structure peaks at 19.88°, while the thermogravimetric analysis of the film samples exhibited 75−80% of the weight loss of TPS film in the second phase between temperatures of 300 °C to 400 °C. All films exhibited homogenous, transparent surfaces with flexibility, and completely degraded in 5 days in simulated river water and composting soil environments, which confirmed TPS as a promising film polymer in food packaging.
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