Gallic Acid Equivalent Kg-1 Research Articles

Investigation of antioxidant and sensory properties and in vitro bioaccessibility of low-fat functional cookies substituted with wheat germ flour and coffee silverskin.

This study aimed to produce new functional cookies with high nutritional properties and low calorie content. It investigated the effects of incorporating wheat germ flour (WGF) at levels of 10-30% as a substitute for whole wheat flour (WWF), along with coffee silver skin (CSS) in the same proportions, serving as natural functional additives to substitute for fat in cookie formulations. The total phenol content of the cookies with added WGF-CSS ranged from 1813.72 to 1838.45 mg gallic acid equivalent (GAE) per kilogram of dry weight (mg GAE kg-1 ), whereas the total phenolic bioaccessibility values ranged between 53.39 and 56.84%. Of the three methods used to determine antioxidant capacity (AC), the cupric reducing antioxidant capacity (CUPRAC) method gave higher bioaccessibility values (44.55-51.19%) than the 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation and 2,2-diphenyl-1-picrylhidrazyl (DPPH) scavenging methods. The contribution of WGF-CSS supplemented cookies to the recommended dietary allowances (RDA) (%) of K, P, Mg, and Ca increased depending on the number of cookies consumed and the WGF and CSS ratio. The general acceptability scores of the cookies varied between 5.66 and -7.08, and the 10% WGF cookie (F2) (6.48) sample received the score that was closest to that of the control. Moderately strong positive relationships (r > 0.90, P < 0.05) were detected between the physicochemical and sensory characteristics of the cookies. As a result, WGF and CSS food additives with high nutritional properties can be recommended as potential enriching ingredients and fat substitutes in the development of new products in the functional food industry. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of extraction methods on phytochemical constituents and antioxidant activity of de-kernelled Sclerocarya birrea seeds.

Marula (Sclerocarya birrea) is an indigenous African fruit-bearing tree with many commercial uses; however, de-kernelled seeds generated from marula fruit-processing are wasted. The phytochemical constituents of de-kernelled marula seeds have not been investigated previously and its extract/tea may potentially serve as a promising source of antioxidants and phytochemicals. This study aimed to investigate the effect of different extraction methods (maceration and decoction) on the recovery of phenolic compounds, sugars, organic acids, and antioxidants from de-kernelled marula seeds. Extracts produced from decoction for 30 min contained the highest phenolic content (2253.93 ± 25.72 mg gallic acid equivalent kg-1 extract), flavonoid content (1020.99 ± 23.90 mg rutin equivalent kg-1 extract), as well as combined sugars and organic acids (1884.03 mg kg-1 extract). Fourier-transform infrared spectroscopy analysis confirmed the presence of functional groups typically present in phenolic compounds, sugars, and organic acids in the extracts obtained from decoction. The characterization revealed that decoction extraction increased solubility, variety, and yield of phytochemical and antioxidant compounds recovered from de-kernelled marula seeds. The highest concentrations of phytochemicals were obtained using the decoction method. This study may therefore pave the way for extract composition and future utilization of de-kernelled marula seeds in the food industry. © 2023 Society of Chemical Industry.

Proximate analysis of the high phytochemical activity of encapsulated Mandai cempedak (Artocarpus champeden) vinegar prepared with maltodextrin and chitosan as wall materials

Background: Mandai cempedak vinegar (MCV) is a fermented vinegar produced from the inner skin of cempedak (Artocarpus champeden), which contains antioxidants classified as flavonoids, phenols, and tannins. These bioactive compounds are sensitive to heat and prone to oxidative damage. Therefore, an encapsulation process is proposed to protect the bioactive compounds. This study aimed to design a potential scaling-up formulation of spray-dried encapsulated MCV based on Total Soluble Solid (TSS) with the addition of maltodextrin and chitosan, followed by determining the nutrition and phytochemical values of the formulation. Methods: The formulation employed maltodextrin to achieve TSS of 15, 20, and 25 ºBrix as the primary wall material treatment factor. The second factor was chitosan as auxiliary wall material at 1, 2, and 3% (w/w of maltodextrin). Products were spray-dried at 100 ºC inlet temperature and 80 ºC outlet temperature. Analyses of nutrition, flavonoid, phenol, and tannin were conducted in triplicate for each encapsulated product. Results: The 15 ºBrix of TSS from maltodextrin with 1% chitosan emerged as the best-encapsulating material, giving 7.54% moisture, 0.75% ash, 0.42% protein, 0.35% fat, and 90.94% carbohydrate content, resulting in a phytochemical activity equivalent to 9.13 mg Catechin Equivalent kg-1, 69.61 mg Gallic Acid Equivalent kg-1, and 25.04 mg Tannic Acid Equivalent kg-1. Compared to maltodextrin, the chitosan generally contributed less to the proximate, flavonoid, phenol, and tannin content of the encapsulated MCV. Conclusions: The best formulation contained maltodextrin at 15 ºBrix of TSS and 1% chitosan. Maintaining optimum TSS was a key to producing consistent encapsulated MCV with high phytochemical activity.

Determination of some functional and sensory attributes and suitability of colored- and noncolored-flesh potatoes for different cooking methods

Twenty-two colored-flesh potatoes and three commercial noncolored-flesh varieties – which were all raw as they were microwaved (800 W, 8 min) and fried (180 °C, 5 min) – were characterized in terms of functional, sensory aspects and suitability for use. Twelve genetic samples were more suitable for frying (> 20% dry matter), four for boiling (~15-18% dry matter) and nine for preparing puree or roasting (~18 to 20% dry matter). The total polyphenol content (TPC) of the raw colored-flesh potatoes contained between 1.10 to 3.68 g of gallic acid equivalent kg-1 in fresh weight (FW), which was between two- and three-fold higher than the measured values in noncolored-flesh varieties. The total antioxidant capacity (TAC) was between 1.00 to 4.71 g of Trolox equivalent kg-1 FW, which was also lower in noncolored-flesh potatoes. The cooking process (frying and microwave) did not affect the TPC in most of the genetic samples analyzed, but it reduced the TAC by 40-75% (fried) and 30-90% (microwaved). According to sensory evaluation results, the genetic samples R2, R19, R3 and R5 were suitable for frying, while R16, R21, R9, R15 and R22 were suitable for microwaving. Colored-flesh potatoes are an interesting alternative for consumers due to their greater phytochemical content.

Evaluation of Egyptian honeys and their floral origins: phenolic compounds, antioxidant activities, and antimicrobial characteristics.

This study reports the physicochemical characterization of clover (Trifolium hybridum) and citrus (Citrus sinensis) honeys produced in Fayoum, Egypt, by evaluating the analysis of moisture content, pH, total soluble solids (TSS), electric conductivity (EC), total sugars, crude protein, ash content, total acidity, hydroxymethylfurfural (HMF), and total phenolic compounds (TPC). Antioxidant and antimicrobial activities of honey extracts and their flower extracts were determined. The results clearly indicated that ethanol gave the highest extraction yield of both clover and citrus flowers, while ethyl acetate showed the highest extraction recovery for the phenolic compounds, with TPC amounting to 338.5 and 536.4mg gallic acid equivalent kg-1 fresh weight in clover and citrus flower extracts, respectively. Honey samples have less TPC than their flowers. The results showed that the TPC of citrus honey and its flowers was higher than clover honey and its flowers, respectively. Antioxidant activity was higher in extracts obtained from citrus flower than extracts of clover flower. The same trend was noticed for honey samples. Both clover and citrus honeys showed antimicrobial effects against tested microorganisms. HPLC analysis showed that p-coumaric acid was the main phenolic component in ethanol extracts of clover and citrus honeys, contributing about 83.0% and 52.2%, respectively. In citrus and clover flower extracts, syringic acid and quercetin were the main phenolics, respectively. It would be expected that characteristics of honey samples are mainly depended on the floral origin of nectar foraged by bees.

Optimization of ultrasound-assisted extraction of phenolic compounds and antioxidant activity from Argel (Solenostemma argel Hayne) leaves using response surface methodology (RSM).

In this study, phenolic compounds were extracted from Argel leaves using an ultrasound-assisted extraction (UAE) method. The extraction parameters (sonication temperature, time, and ethanol concentration) were optimized using a response surface methodology (Box-Behnken design), in order to maximize the total phenolic content (TPC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity of Argel leaf extracts (ALEs). The phenolic compounds of the ALEs obtained under optimized conditions were also identified. The optimum UAE conditions for achieving maximum TPC (72.27g gallic acid equivalents kg-1 DW) and DPPH scavenging activity (86.15%) were a 60°C temperature, a 37.07min duration, and a 39.14% ethanol concentration. Under these conditions, the experimental values of TPC and DPPH scavenging activity were 73.02g GAE kg-1 and 85.56%, respectively, which agreed with the predicted values. In addition, the major phenolic acids found in ALEs under the optimized extraction conditions were sinapic, p-coumaric, and ferulic acid. Overall, the findings of this study demonstrated the suitability of UAE and the success of RSM in optimizing the extraction conditions of bioactive compounds from ALEs.

Vitis vinifera Turkish grape cultivar Karaerik. Part I: anthocyanin composition, and identification of a newly found anthocyanin†.

Grape berries exhibit various beneficial health effects due to the potent antioxidant roles of their phenolic compounds. A new Vitis vinifera grape cultivar (Karaerik) grown in Turkey has attracted growing interest due to its antioxidant phenolic compounds, which have still not been investigated. The phenolic/anthocyanin profile needs to be investigated to ascertain its potential health benefits and market value in the region. The present study therefore involves a detailed characterization of the anthocyanin composition of 'Karaerik' grape berries in conjunction with a determination of the antioxidant capacity value of the phenolics present in the skin and the whole berry. Total phenolic compounds (average 8.56 and 2.88g gallic acid equivalent kg-1 fresh weight) and anthocyanin (7.48 and 1.66 g mv-3-glc equivalent kg-1 fresh weight) contents varied significantly in the skin and whole berry. Malvidin-based anthocyanins made the highest contribution to the pigment content of the berry. Accordingly, the major anthocyanin in the skin (average 42.08 mol%) and whole berry (39.98 mol%) was malvidin-3-glucoside (mv-3-glc). In addition, we found strong evidence of the occurrence of sometimes reported malvidin-3-pentoside and particularly of the not previously reported feruloyl derivative of malvidin-3-(6″-feruloyl)-glucoside (mv-3-ferglc) for V. vinifera grapes. The current study is the first report to profile the anthocyanins of the grape with a detailed description of the rare and novel anthocyanin in V. vinifera grapes. The berry is also a potential source of phenolics/anthocyanins with a high antioxidant capacity value and is worthy of comparison with other V. vinifera grapes. © 2019 Society of Chemical Industry.

Antioxidant Sources from Leaves of Russian Dandelion.

Taraxacum kok-saghyz (TKS) is a dandelion species native to Kazakhstan, Uzbekistan and north-west China, considered as a promising alternative source of natural rubber from its roots. The aim of this study was to investigate the possible exploitation of TKS leaves, a rubber byproduct, as a source of phenolic compounds with antioxidant properties for potential applications in forage, nutraceutical and pharmacological fields. Two accessions (TKS016, TKS018) grown under Mediterranean conditions of Sardinia were evaluated at vegetative and flowering stages. The leaves of TKS018 had the highest antioxidant capacity (19.6 mmol trolox equivalent antioxidant capacity 100 g-1 ), total phenolic (106.4 g gallic acid equivalent kg-1 ), tannic phenolics (58.5 g gallic acid equivalent kg-1 ) and total flavonoid contents (22.9 g catechin equivalent kg-1 ). At both phenological stages, TKS016 showed significantly lower values than TKS018 in 1,1-diphenyl-2-picrylhydrazyl (DPPH), total phenolic and tannic phenolics. Six individual molecules were identified, namely chlorogenic, cryptochlorogenic, caffeic, sinapic, chicoric and 3,4-dimethoxycinnamic acids. Chicoric (8.53-10.68 g kg-1 DW) and chlorogenic acids (4.18-7.04 g kg-1 DW) were the most abundant. TKS leaves represent a valuable source of chicoric acid with potential application as antioxidant to be used as herbal medicine and nutrition for production of healthy food/feed.

Polyphenolic composition and antioxidant capacity of legume-based swards are affected by light intensity in a Mediterranean agroforestry system.

In Mediterranean grazed woodlands, microclimate changes induced by trees influence the growth and development of the understory, although very little is known about its polyphenolic composition in relation to light intensity. We investigated the bioactive compounds and antioxidant capacity of different legume-based swards and variations as a result of full sunlight and partial shade. The research was carried out in a cork oak agrosilvopastoral system in Sardinia. The highest values of (1,1-diphenyl-2-picrylhydrazyl) (DPPH) reached 7mmol Trolox equivalent antioxidant capacity 100 g-1 dry weight (DW), total phenolics 67.1g gallic acid equivalent kg-1 DW and total flavonoids 7.5g catechin equivalent kg-1 DW. Compared to full sunlight, partial shade reduced DPPH values by 29% and 42%, and the total phenolic content by 23% and 53% in 100% legume mixture and semi-natural pasture, respectively. Twelve phenolic compounds were detected: chlorogenic acid in 80% legume mixture (partial shade) and verbascoside in pure sward of bladder clover (full sunlight) were the most abundant. Light intensity significantly affected antioxidant capacity, composition and levels of phenolic compounds. The results of the present study provide new insights into the effects of light intensity on plant secondary metabolites from legume-based swards, highlighting the important functions provided by agroforestry systems. © 2018 Society of Chemical Industry.

Berries grown in Brazil: anthocyanin profiles and biological properties.

Phytochemical profiles of two Brazilian native fruits-pitanga (red and purple) and araçá (yellow and red)-as well as strawberry cultivars Albion, Aromas and Camarosa, blackberry cultivar Tupy and blueberry cultivar Bluegen cultivated in Brazil were characterized for total phenolic content and total anthocyanin content by liquid chromatography coupled to a photodiode array and a quadrupole time-of-flight mass spectrometer. Radical scavenging, antiherpes and cytotoxic activities of these berry extracts were also evaluated. Blueberry presented the highest total anthocyanin content (1202 mg cyanidin-O-glucoside equivalents kg-1 fresh fruit), while strawberry cultivar Aromas presented the highest total phenolic content (13 550 mg gallic acid equivalents kg-1 fresh fruit). Liquid chromatographic-mass spectrometric analysis resulted in the identification of 21 anthocyanins. To the best of our knowledge this is the first report of cyanidin-O-glucoside in yellow and red Araçá fruit and the first time eight anthocyanins have been reported in pitanga fruits. DPPH and ABTS assays showed that blueberry cultivar Bluegen, blackberry cultivar Tupy and pitanga (red and purple) showed the most promising antiradical activities, respectively. No relevant cytotoxicity against three cancer cell lines or antiherpes activity was detected under the experimental conditions tested. Total anthocyanin content of all fruits had a strong positive correlation with their free radical scavenging activity, suggesting anthocyanins contribute to the antioxidant potential of these fruits. © 2018 Society of Chemical Industry.

Cucurbita maxima Pumpkin Seed Oil: from the Chemical Properties to the Different Extracting Techniques

Pumpkin seed oils are rich in bioactive compounds such as tocopherols, sterols, β-carotene, and lutein that have, along with some fatty acids, high nutritional value factors. In addition, it has so far been proven that these compounds have a positive effect on human health. The present study mainly aimed at evaluating the chemical composition and the bioactive compounds of pumpkin (Cucurbita maxima) seed oil of the ‘Béjaoui’ Tunisian cultivar using both cold pressing and solvent extraction methods. The seed oils contained substantial amounts of unsaturated fatty acids, particularly oleic and linoleic acids, with values ranging respectively from 28.19% for cold pressed pumpkin seed oil to 30.56% for pumpkin seed oil extracted by pentane and from 43.86% for pumpkin seed oil extracted by pentane to 46.67% for cold pressed pumpkin seed oil of the total amount of fatty acids. Investigations of different seed oils revealed that extraction techniques had significant effects on the antioxidant activity and the γ-tocopherol. Cold pressed pumpkin seed oil revealed the highest γ-tocopherol content (599.33 mg kg-1) and the highest oxidative stability (3.84 h). However, the chloroform/methanol extracted pumpkin seed oil, which is rich in total phenolics (54.41 mg Gallic Acid Equivalent kg-1), was a more effective scavenger of DPPH radicals (250 µmoles Trolox kg-1) than the poor phenolic pumpkin seed oils extracted by hexane and pentane (110 µmoles Trolox kg-1 vs 100 µmoles Trolox kg-1). Based on its unique seed oil features, cold press extracted pumpkin seed may add great value to product innovation in the industrial, nutritional, cosmetic, and pharmaceutical fields.

In vitro digestibility, free and bound phenolic profiles and antioxidant activity of thermally treated Eragrostis tef L.

Total phenolic content, phenolic profile and antioxidant activity were determined in free and bound phenolic fractions of thermally treated brown and white teff grains. Phenolic content in raw brown and white teff (1540 and 992 mg gallic acid equivalent kg-1 ) as well as antioxidant activity (6.3 and 5.5 mmol trolox equivalent kg-1 ) were higher in free phenolic fractions. The most significant decrease in total phenolics was observed after application of the sous-vide method (35% for brown teff and 11% for white teff). Main free phenolics of heat-treated teff were ferulic, protocatechuic, p-coumaric and ellagic acids, rutin and epigallocatechin. Main bound phenolics were ferulic, gallic, sinapic and ellagic acids, catechin and epigallocatechin. The detrimental effect on free and bound quercetin and bound cinnamic acid concentrations was also examined during heat treatment. Thermally treated brown teff showed a high level of in vitro organic matter digestibility if water cooking and rice cooker (both 99.5%) and sous-vide (96.5%) methods were applied. The sous-vide method may be recommended as the most suitable hydrothermal treatment for grains of teff when compared with water cooking and rice cooker methods. © 2017 Society of Chemical Industry.

Preponderance of Bioactive Medicinal Compounds and ATR-FTIR Spectroscopy of Coriander and Mustard Floral Honey from &lt;i&gt;Apis mellifera&lt;/i&gt;

The physicochemical, total phenolics, flavonoids, and antioxidant activity were evaluated for biochemical characterization of coriander and mustard floral honey. The total phenolics, flavonoids and antioxidant activity were analyzed using UV-VIS spectrophotometer. Fourier transform infrared spectroscopy (FT-IR) was used to evaluate the chemical characteristic of coriander and mustard floral honey. The total phenolics content was ranged from 294 to 462 mg gallic acid equivalent kg-1 of honey. The total flavonoid content was ranged from 43 to 53 mg quercetin equivalent kg-1 of honey. Antioxidant activity results were expressed as inhibitory concentration (IC50) value ranged from 4.58 to 5.54 mg mL-1. FT-IR spectra showed the presence of alcohols, carboxylic acids, esters, ethers, phenols, and amines in both floral honey samples. This study discovered that coriander floral honey is more affluent than mustard floral honey in nutritional as well as medicinal aspects. At a glance the processing of honey by heating did not affect the phenolics, flavonoid, and antioxidants of honey; even processed honey contains higher phenols and antioxidants. The FT-IR spectra showed the similarity in both kinds of honey refers to chemical constituents. This study will help the researcher and honey consumer to find out the higher bioactive medicinal compounds containing honey.

Vaccinium meridionale Swartz extracts and their addition in beef burgers as antioxidant ingredient.

Vaccinium meridionale Swartz (mortiño) constitutes a source of bioactive phytochemicals, but reports related to its efficient and green production are scarce. In this study, pressurized liquid extraction (PLE) and ultrasound-assisted extraction of mortiño were compared. Total phenolic content (TPC) and antioxidant capacity (ABTS•+ ) were determined. Beef burgers with 20 g kg-1 of mortiño (MM) or its PLE extract (ME) were manufactured. Lipid oxidation (TBARS) and instrumental color changes were measured after refrigerated storage. High TPC (up to 72 g gallic acid equivalent kg-1 extract) was determined in mortiño extracts, which was positively correlated with antioxidant activity. TBARS values of beef burgers containing either MM or ME did not change after refrigerated storage, whereas lipid oxidation of control burgers increased significantly. The color of burgers with added MM or ME was different (lower b* and a* values) from that of control burgers. However, the evolution of color after storage was similar between control and ME samples. Mortiño extracts with high TPC can be obtained by PLE. Both mortiño and its PLE extract are able to control lipid oxidation of beef burgers, but the extract is preferred from the color quality point of view. © 2017 Society of Chemical Industry.

High total phenol content, antioxidant activity and mineral content in ‘Sweetheart’ cherry peel

Cherry is used for several processed products, resulting in a large volume of subproducts, mainly stones and peel. For evaluation of nutritional potential of some sub products, total phenol content (Folin-Ciocalteu reagent method), antioxidant activity (DPPH method), and calcium, magnesium, sodium, potassium and phosphorus content (ICP-AES) were determined in 'Sweetheart' cherry peel. Results were compared with those of 'Tulameen' raspberry fruit cultivated in the same region. Raspberry is recognised to having a high level of antioxidants, minerals and fibre. Average concentrations of 2793.8 mg gallic acid equivalent kg-1, 3450.9 mg TE kg-1, (Ca) 317.7, (Mg) 267.5, (Na) 9.8, (K) 2196.2, and (P) 407.5 mg kg-1 were found in 'Sweetheart' cherry peel. Regarding raspberries, concentrations of 1411.8 mg gallic acid equivalent kg-1, 2709.5 mg TE kg-1, (Ca) 281.9, (Mg) 227.2, (Na) 1.3, (K) 1646.7, and (P) 76.7 mg kg-1 were found. All nutritional concentrations in peel were significantly higher than in the remaining fruit, showing its potential for nutrition complement production.

Impact of Clonal Variability on Phenolics and Radical Scavenging Activity of Grapes and Wines: A Study on the Recently Developed Merlot and Cabernet Franc Clones (Vitis vinifera L.).

In this study, grapes and corresponding wines of Merlot /No 022, 025 and 029/ and Cabernet Franc /No 02, 010 and 012/ clones (recently developed) were evaluated regarding the total phenolic content, total anthocyanin content, and radical scavenging activity, aiming to better understand their quality and market potential. The nineteen individual polyphenols were quantified in studied grape samples using UHPLC coupled to a triple-quadrupole mass spectrometer. The mother grapes and wines were used as the relevant standards. In the grape, studied characteristics were monitored at three stages of berry development: green berry, véraison and mature berry. The mature grape of clones presented high values of total phenolics (3.81–10.89 g gallic acid equivalent kg-1 frozen weight), anthocyanin content (359.00–1668.18 mg malvidin-3-O-glucoside kg-1 frozen weight) and the radical scavenging activity (41.37–80.48 mmol trolox equivalent kg-1 frozen weight) depending on the clone. Grapes and wines of Merlot No 025 and Cabernet Franc No 010 stood out with the highest values of all three parameters. Generally, the high correlation was observed between TPC and RSA values for green berries and mature grapes, as well as for wine samples. The most abundant phenolics in both Merlot and Cabernet Franc grapes were gallic acid, p-hydroxybenzoic acid, ferulic acid, catechin, epicatechin, gallocatechin gallate, catechin gallate, and rutin. Catechin, epicatechin, epigallocatechin, and catechin gallate, typical for the ripe grape of Merlot and Cabernet Franc clones, showed significant correlation with RSA values. Concentrations of individual polyphenols varied depending on the sample being studied and berry development stages. Merlot No 025 and Cabernet Franc No 010 grapes showed particularly interesting attributes for the production of high quality wines.

Quality changes of green vegetable smoothies during shelf-life

The health-promoting benefits of the Mediterranean diet are related to consumption of fruits and vegetables, which are important sources of phytochemicals such as phenolics, carotenoids and vitamin C. Smoothies are an excellent solution to ingest these health-promoting compounds in an easy way and increase fruit and vegetable consumption. Two different fresh green vegetable smoothies, V1 (tomato, carrot, broccoli and spinach, making up 90% of the composition) and V2 (90% cucumber and broccoli), were lightly processed with a mild heat treatment. Fresh blended unheated smoothies were used as controls. Physicochemical, sensory, microbial and nutritional/bioactive (vitamin C, phenolics, antioxidant capacity, carotenoids and chlorophylls) and quality analyses were studied during 7 days at 5 or 20°C. Generally, soluble solids content, pH and titratable acidity did not change greatly after 7 days at 5°C. Initial total phenolics content [305.5/292.7 mg gallic acid equivalent kg-1 f.w.] was generally preserved throughout storage. Initial total vitamin C contents (79/155 mg kg-1 f.w.) showed 58-56% reduction even after the heat treatment, while a progressive decrease was generally observed, which was remarked in fresh blended smoothies. In conclusion, fresh blended green vegetable smoothies can preserve good quality for a week at low temperature, while a mild thermal treatment may extend the shelf-life, but will influence some quality attributes. Further studies should enhance smoothie composition and time-temperature heat treatment parameters for optimized minimal processing and extended shelf-life.

The antioxidant capacity and macroelement content of several onion cultivars

Abstract: The aim of this study was to determine the phosphorus, magnesium, sodium, potassium, and calcium contents, as well as the total phenolic content and antioxidant activity in white, yellow, and red onion varieties. It is evident from the results that the highest content of all of these macroelements except phosphorus was found in the cultivar Fireball. In this cultivar, the phosphorus content was the lowest of all cultivars. The total phenolic content ranged from 1.17 to 2.10 g of gallic acid equivalents kg-1 and the antioxidant capacity ranged from 1.26 and 1.86 g of ascorbic acid equivalents kg-1 of fresh weight and was slightly higher in red onion cultivars than in white and yellow cultivars. The significant influence of color was determined by total phenolic content, antioxidant capacity, and macroelements except phosphorus (P < 0.05). While the season had influence on phosphorus and potassium content and on antioxidant capacity, the growing season significantly influenced the total phenolic content of the onions.