Red Grape Juice Research Articles

A turn-on fluorescent probe for vitamin C based on the use of a silicon/CoOOH nanoparticle system

The authors describe a fluorometric method for the turn-on determination of vitamin C (ascorbic acid). The blue fluorescence of silicon nanoparticles (SiNPs; with excitation/emission maxima at 350/450nm) is found to be quenched by CoOOH nanoparticles (NPs). In the presence of vitamin C, the CoOOH NPs are decomposed by a redox reaction between the diol group of vitamin C and CoOOH NPs. As a result, fluorescence recovers. On the basis of this finding, a fluorometric method was designed for the turn-on detection of vitamin C. Under optimal conditions, the method has a low detection limit (0.47μM) and a linear response in the 0.5μM to 20μM a concentration range. It was successfully applied to the determination of vitamin C in spiked red grape and orange juice, and in vitamin C tablets. Graphical abstract A target-triggered dissociation of quencher-based strategy for the fluorescence "turn-on" detection of vitamin C was developed. It is based on surfaceenergy transfer (SET) and an inner filter effect (IFE) between silicon nanoparticles and CoOOH nanoparticles as well as the redox reaction between vitamin C and CoOOH nanoparticles.

Polyphenolic profile, macro- and microelements in bioaccessible fractions of grape juice sediment using in vitro gastrointestinal simulation

Grape and grape constituents have high amounts of essential minerals and polyphenols. Health benefits of these nutrients and other bioactive substances depend on their level of intake and bioaccessibility. The behavior and levels of individual phenolic compounds, macro- and microelements of the grape juice sediment that was removed from red grape juices of Bordo and Isabel varieties were investigated using an in vitro digestion and determined using high performance liquid chromatography-diode array detection and inductively coupled plasma optical emission spectrometry. During digestion, important changes were observed in concentrations of polyphenols and minerals upon passage through the gastric and enteric phases. Bioactive compounds such as trans-resveratrol, catechin and epicatechin were highly bioaccessible from the Bordo sample. A significant decrease in levels of polyphenolics and minerals was observed at the end of the intestinal phase. The grape juice sediment of both varieties showed higher antioxidant capacity in the gastric phase, which was related to the high concentration of polyphenols. The anthocyanins identified at higher concentrations in samples included malvidin-3-O-glucoside and malvidin-3,5-diglucoside that were 7% and 60% bioaccessible, respectively. The elements Ca, Mg, Cu, Fe, Sr, Mn, Zn, Al, Ni and Pb were not detected at the last phase of digestion, being poorly bioaccessible. The bioaccessibility indexes found for this grape juice sediment are consistent with the bioactive properties of grape products.

Resveratrol Sustains Insulin-Degrading Enzyme Activity toward Aβ42.

Alzheimer’s disease (AD), the most common cause of dementia in the elderly, is the sixth leading cause of death in the United States. We hypothesize that the impaired clearance of Aβ42 from the brain is partly responsible for the onset of sporadic AD. In this work, we evaluated the activity of insulin-degrading enzyme (IDE) toward Aβ42 in the presence of resveratrol, a polyphenol found in red wine and grape juice. By liquid chromatography/mass spectrometry, we identified initial cleavage sites in the absence and presence of resveratrol that carry biological relevance connected to the amyloidogenic properties of Aβ42. Incubation with resveratrol results in a substantial increase in Aβ42 fragmentation compared to the control, signifying that the polyphenol sustains IDE-dependent degradation of Aβ42 and its fragments. Our findings suggest that therapeutic and/or preventative approaches combining resveratrol and IDE may hold promise for sporadic AD.

Molecularly Imprinted Polymer for Selective Extraction of Tartaric Acid

A molecularly imprinted polymer (MIP) was synthetized through precipitation polymerization method for the detection of tartaric acid. Acrylamide or methacrylic acid as functional monomers as well as amount of cross-linker were regarded as polymerization variables. The reactants were dissolved in acetonitrile-ethanol (8 : 2) solution. The synthetized polymers were characterized by HPLC, fourier transform infrared spectrometry (FTIR), thermogravimetric and dynamic light scattering techniques. Batch adsorption experiments with control by HPLC revealed better binding capacity of acrylamide-based polymers compared to methacrylic acid polymers in phosphate buffer saline solution as binding medium. Highest binding capacity was obtained at 30 : 1 cross-linker to template ratio. Tartaric acid complexation with acrylamide was affirmed by FTIR. Tartaric acid is the dominant acid in red grape and can be utilized as red grape juice “fingerprint” in other juices like pomegranate juice which is known to be adulterated in beverage industry. Based on the obtained results, this easily synthesized polymer for tartaric acid can be used in the detection of the presence of red grape juice in pomegranate juice. The synthesized MIP can potentially be applied in sensors for tartaric acid.

Degradation kinetics of anthocyanins and polyphenols during storage of red apple juice produced from red-fleshed apples

The aim of this study was to determine the stability of various anthocyanins in red-coloured apple juice for the development of a new attractive beverage. Red-coloured apple juice was generated from red-fleshed apples of cultivar “Maggy” to analyse the composition of anthocyanins and the effect of storage at various temperatures. Cyanidin-3-galactoside (cy-3-gal) was identified as the main component of the anthocyanin profile, next to 5-carboxypyranocyanidin-3-hexoside, tentatively carboxypyranocyanidin-3-galactoside, and two cyanidin-3-pentosides. In addition, we found cyanidin-3-glucoside, another 5-carboxypyranocyanidin-3-hexoside, probably 5-carboxypyranocyanidin-3-glucoside, one 5-carboxypyranocyanidin-3-pentoside, two unknown anthocyanins, and another cyanidin-3-pentoside. The loss of anthocyanins during storage can be described as a first-order reaction as it is the case also for other red-coloured fruit juices. The T1/2 value of cyanidin-3-galactoside varied between 53 and 84 days after storage at 4 °C, and between 15 and 13 days at 20 °C. Storage at 37 °C reduced the T1/2 values from 7 to 6 days. A much longer half-life was observed for 5-carboxypyranocyanidin-3-galactoside. The T1/2 values at 4 °C were 250–315 days and 50–112 days at 20 °C. At 37 °C, T1/2 decreased from 23 to 25 days. The antioxidant capacity (TEAC) was constant during storage for at least 1 year. The colour of red apple juice, however, is less stable than in aronia, black currant and red grape juices, for example. Taken together, red apple juice, generated of the cultivar “Maggy”, is an attractive new fruit juice, but other cultivars of red-fleshed apples with higher anthocyanin concentrations would achieve a more colour-intense product.

Evaluation of gamma irradiation effect on physico-chemical properties of a mixed beverage based in soy milk and grape juice

The aim of this study was to evaluate the effect of gamma radiation on the physico-chemical parameters in a mixed beverage (white or red grape juice + soy milk). The radiation doses were used: 1, 3, 6 and 9 kGy. Most of the parameters evaluated did not change in both beverages at different doses, with the exception of the 9 kGy dose that reduced the antioxidant capacity and the phenolic compounds, and increased the peroxidase. Thus, the gamma radiation can be used in mixed beverages, but doses below 9 kGy, avoiding changes in physico-chemical quality.

The simultaneous effect of electromagnetic and ultrasound treatments on Escherichia coli count in red grape juice

Introduction: The thermal pasteurization is a common method for maintaining fruit juice and increasing shelf life, but the thermal processing changes the flavor and color of the products. The aim of this study was to investigate the effect of a new method of combining heat and ultrasound on the number of the Escherichia coli present in grape juice.Methods: In this study, the effects of the microwave power, temperature, ultrasound power and ultrasonic exposure time were evaluated on E. coli count of red grape juice. In order to determine the microbial inactivation by microwave and ultrasound, E. coli at a concentration of 6×106 per mL was inoculated to red grape juice.Results: The effects of microwave power, grape juice temperature, ultrasound power and ultrasonic exposure time on the reduction of E. coli were significant (P < 0.05). The model showed that in reducing E. coli the importance of the final temperature of the juice was higher than the microwave power. In addition, the ultrasonic power was more effective in E. coli reduction as compared to the microwave power.Conclusion: Both sample temperature and ultrasonic duration were important independent variables and effective factors on E. coli reduction.

RED WINE, GRAPE JUICE OR RESVERATROL CONSUMPTION EFFECTS ON LIPID AND GLYCEMIC PROFILE AND HEPATIC MORPHOLOGY OF WISTAR RATS SUBMITTED TO HIGH FAT DIET AND PHYSICAL TRAINING

The aim of this study was to evaluate the effects of red wine, grape juice or resveratrol consumption on lipid and glycemic profile and liver nuclear area and circularity of Wistar rats submitted to the high fat diet and physical training. Wistar rats, with 90 days, were divided into 5 groups: Control (GC); High Fat (HFG); Grape Juice (GJG); Red Wine (WG) and Resveratrol (RG). The animals performed a running protocol. After 60 days, the animals were anesthetized, blood was collected for biochemical analyzes, sacrificed and the liver removed. Liver samples were mounted on histological slides and stained with hematoxylin and eosin. The results were expressed as mean ± standard deviation and assessed for normality with Kolgomorov-smirnov test. One way ANOVA, and Bonferroni post-test were used. It was considered significant when p <0.05, using PRISMA 5.0 software. Groups consuming high fat diet had a significantly higher energetic intake compared to CG, however, there was no significant difference in body mass and weight gain among groups. There was no significant difference in glucose and triglyceride levels among groups. Total cholesterol and high density lipoprotein (HDL) were higher in GJG when compared to the other groups. Hepatocytes nuclear areas were significantly higher in the HFT and WG, with no difference in nucleus circularity among groups. It was concluded that grape juice showed better results in biochemical analysis and the resveratrol solution presented better results in liver morphology.

Protective effects of red grape (Vitis vinifera) juice through restoration of antioxidant defense, endocrine swing and Hsf1, Hsp72 levels in heat stress induced testicular dysregulation of Wister rat

Ability of red grape juice (RGJ), a known antioxidant, on testis of adult Wister rat to protect from oxidative stress induced damages by heat stress has been investigated in this study. Heat stress was induced maintaining body and testicular temperature at 43°C for 30min/day for 15 days using a hyperthermia induction chamber. Four groups of rats (n=6 per group) comprising of Group-I (control) –kept at 32°C, Group-II –exposed to heat stress alone, Group-III received RGJ (0.8ml/rat/day) alone and Group-IV –exposed to heat stress and received RGJ at same dose. Analysis of blood and testicular tissue exhibited significant reduction in serum testosterone, testicular superoxide dismutase, testicular catalase and testicular glutathione (all p < 0.001); whereas, significant rise in the level of serum corticosteroid, testicular lipid peroxidase and the apoptotic enzyme caspase-3 of testis (all p < 0.001) were observed along with substantial increase in testicular Hsp72 and Hsf-1, and decrease in 17β-HSD3 were noted in heat stressed rats compared to controls. In Group-IV rats, RGJ administration could restore these parameters to normal levels. The signs of retention were clear in Group-IV rats and found to be significantly different as compared to that of the Group-II rats. In testicular histology of rats exposed to heat stress alone revealed remarkable germ cell degeneration and tubular deformations which were prevented by RGJ treatment (Group-IV). The reduced number of sperm level in Group-II also restored in RGJ treatment (Group-IV). The above results indicate that consumption of RGJ may substantially protect testis from heat stress induce dysfunctions.

Effects of red wine, grape juice and resveratrol consumption on bone parameters of Wistar rats submitted to high-fat diet and physical training.

intake of diets with high saturated fat may produce deleterious effects on bone mineralization. Lifestyle changes help reduce the bone loss observed in osteoporosis. Resveratrol, present in grape juice and red wine, has osteogenic and osteoinductive effects, being potentially beneficial for bone health. to evaluate the effects of red grape juice, red wine and resveratrol consumption on bone parameters in Wistar rats submitted to a high-fat diet and physical training. female Wistar rats, with 90 days of age, were divided into five groups and followed up for 60 days: a) control group; b) high-fat group; c) grape juice group; d) red wine group; and e) resveratrol group. The different groups of animals performed a physical training protocol. Animal's weight and consumption were monitored weekly. After 60 days, femoral dimensions, bone mineral density (BMD) and bone mineral content (BMC) were evaluated. there was no difference in body mass; however, all groups consuming the high-fat diet had higher consumption (p < 0.05). RWG presented a greater distance between the epiphyses, femoral mass and BMC (p < 0.05). RWG and RG presented greater mean diaphysis point width and BMD (p < 0.05). the results suggest that the bioactive compounds present in red wine and resveratrol solution together with regular exercise were able to promote beneficial effects on bone health, even when associated with a high saturated fat diet.

Employing of the Different Fruit Juices Substrates in Vinegar Kombucha Preparation

Background: Vinegar could be counted as one of the oldest acetic acid diluted solution products among the history. It can be produced by various fermentation methods using any sugary substrate, especially fermented fruit juice. Due to the presence of many kinds of compounds which formed in the fermentation process, the final vinegar products could show unique functions. The aim of current study was to produce a new type of vinegar kombucha using different fruit juices substrates. Methods: Kombucha vinegar was obtained by fermentation of kombucha broth layer on sweetened pasteurized fruit juices (pomegranate, red grape, sour cherry and apple). Fermentation took place in 4 L glass vessel and fortified with 2% of previously processed broth. Incubation was carried out at 27±2 °C for 14 days. Several factors such as; pH, total acidity, and acetic acid content, invert sugars, remaining sucrose, alcohol, soluble solids and the yield of biomass were measured periodically (0, 3, 7, 10 and 14 days after processing). Results: As the fermentation continues, the actual concentration of acids, pH value, fructose content and biomass yield significantly increased (P<0.01) but the alcohol and residual sucrose content decreased in all the juices. Contents of acetic acid on 14th day of fermentation were 3.8, 3.6, 3.5 and 3.4 g/100 ml of pomegranate, red grape, sour cherry and apple juice vinegar, respectively. Moreover, soluble solid in kombucha vinegar was determined (24.7, 38.1, 19.1 and 36.5 g/100 ml in pomegranate, red grape, sour cherry, and apple, respectively). Conclusion: The composition of different kombucha preparations is greatly affected by the individual kombucha layer used. Keywords: Acetic acid, beverages, fermentation, fruit juice, kombucha vinegar, substrate.

Extraction and determination of volatile organic acid concentration in pomegranate, sour cherry, and red grape juices by PPy-Ag nanocomposite fiber for authentication

ABSTRACTA solid phase microextraction fiber based on nano-sized polypyrrole-Ag (PPy-Ag) was fabricated. The size and morphology of PPy-Ag particles was characterized by scanning electron microscopy (SEM). A method based on PPy-Ag-SPME-gas chromatography (GC) was developed for determination of sour cherry and grape juice adulteration in pomegranate juice samples by determination of volatile organic acids (VOAs) concentration. The VOAs of pomegranate juice (valeric, isovaleric, lactic, and acetic acids) were extracted by fabricated polypyrrole-Ag fiber, and the concentration of VOAs was determined by GC analysis. The effects of pomegranate juice (PJ) percent, sour cherry juice (SCJ) percent, and red grape juice (GJ) percent as three variable factors on the concentration of VOAs were studied. Box Behnken Design (BBD) was applied to design the experiments that study the effect of factors on the VOAs concentration. The results showed that sour cherry and grape juice adulteration in pomegranate juice can affect the VOAs concentration, and there is a good relation between pomegranate, sour cherry, and grape juice percent and VOAs concentration. So the presented analytical method is a suitable and fast method for determination of pomegranate juice authentication.

Technological and Probiotic Properties of Lactic Acid Bacteria Isolated from Hardaliye

Hardaliye is a lactic acid fermented beverage produced from red grape or grape juice with addition of crushed mustard seeds and benzoic acid and can be found in the Thrace region of Turkey. The aims of this study were to determine the dominant species of lactic acid bacteria in hardaliye and to investigate their technological and probiotic properties and potential use as starter culture in the production of Hardaliye. For this aim lactic acid bacteria were isolated from total 28 hardaliye samples (23 hardaliye samples collected from different regions of the Kirklareli in Turkey and 5 hardaliye samples produced with the traditional methods in laboratory conditions) and identified. After carrying out conventional and molecular biological methods, it was found that all species of lactic acid bacteria belonged to genus Lactobacillus . Lactobacillus plantarum was the dominant species in the microbiota. ~98% of the isolates were similar to each other. Therefore, diversity of effective lactic acid bacteria during the fermentation is very low. Given the antimicrobial effects and acid production capabilities of lactic acid bacteria, isolates have potential as starter cultures for use in hardaliye production.

Technological and Probiotic Properties of Lactic Acid Bacteria Isolated from Hardaliye

Hardaliye is a lactic acid fermented beverage produced from red grape or grape juice with addition of crushed mustard seeds and benzoic acid and can be found in the Thrace region of Turkey. The aims of this study were to determine the dominant species of lactic acid bacteria in hardaliye and to investigate their technological and probiotic properties and potential use as starter culture in the production of Hardaliye. For this aim lactic acid bacteria were isolated from total 28 hardaliye samples (23 hardaliye samples collected from different regions of the Kirklareli in Turkey and 5 hardaliye samples produced with the traditional methods in laboratory conditions) and identified. After carrying out conventional and molecular biological methods, it was found that all species of lactic acid bacteria belonged to genus Lactobacillus . Lactobacillus plantarum was the dominant species in the microbiota. ~98% of the isolates were similar to each other. Therefore, diversity of effective lactic acid bacteria during the fermentation is very low. Given the antimicrobial effects and acid production capabilities of lactic acid bacteria, isolates have potential as starter cultures for use in hardaliye production.

Whole Red Grape Juice Reduces Blood Pressure at Rest and Increases Post-exercise Hypotension

ABSTRACTObjective: The objective of this study was to evaluate the effect of whole red grape juice (juice) on blood pressure (BP) at rest and on the magnitude of post-exercise hypotension (PEH).Methods: This double-blind, randomized controlled study was performed with 26 individuals with hypertension (40 to 59 years old) who were divided into experimental (n = 14) and control (n = 12) groups. Subsequently, the experimental group was subdivided according to the initial BP values. The subjects performed 2 sessions of aerobic exercise on a treadmill (60 minutes, 60%–85% maximum heart rate), separated by a 28-day period of supplementation with a daily dose of juice (150 ml for men and 100 ml for women) or a control drink. BP was measured before, during, and immediately after each exercise session as well as every 10 minutes during the 60-minute post-exercise recovery period.Results: The BP at rest did not change in the experimental group, but when this group was subdivided by initial BP, the subjects with controlled initial BP (EGCP) achieved a significant reduction (133.3 ± 5.6 to 114.6 ± 12.2 mmHg, p = 0.02); in contrast, the experimental group with borderline hypertensive BP values (EGBP) did not. Intervention with juice did not modify PEH in the experimental group, but when this group was divided as a function of the initial BP, PEH was potentiated at some times in EGCP.Conclusions: We conclude that juice promotes a reduction in BP at rest and is also capable of improving PEH in individuals with hypertension, but these effects are dependent on the initial BP values.

PHYSICOCHEMICAL COMPOSITION AND SENSORY ANALYSIS OF WHOLE JUICE EXTRACTED FROM GRAPES IRRADIATED WITH ULTRAVIOLET C

ABSTRACT Grape juice has been widely studied due to the presence of phenolic compounds and its beneficial effects on human health. Ultraviolet irradiation C (UV-C) can increase the content of phenolic compounds and anthocyanins and contribute to sensory acceptability. The aim of this study was to evaluate the effect of different doses of ultraviolet irradiation C (UV-C) on ‘Trebbiano’, ‘Niagara Branca’, ‘Isabel’ and ‘Cabernet Sauvignon’ grapes, as well as effect of the storage period. Juices were elaborated and evaluated for physicochemical analyses, and for the sensorial analysis in irradiated samples. In ‘Niagara Branca’ and ‘Trebbiano’ cultivars, storage and irradiation promoted few physicochemical alterations, and sensorially, irradiation reduced the intensity of flavor and color attributes. In juices from ‘Isabel’ and ‘Cabernet Sauvignon’ cultivars, the storage period led to the concentration of sugars and irradiation influenced physicochemical parameters and increased the intensity of aroma attribute at dose of 2 kJ m-2. Thus, UV-C irradiation contributes little for the improvement of white grape juices; however, it favors some sensory attributes in red grape juice, requiring further studies to elucidate the influence of UV-C irradiation on the phenolic and volatile composition of grape juice.

Modeling of drying kinetics of the non‐pomace residue of red grape (V. labrusca L.) juices: Effect on the microstructure and bioactive anthocyanins

AbstractThe clarification of grape juices produces a colored non‐pomace residue that is continuously discarded. This study evaluated the drying kinetics of the non‐pomace residue of organic and conventional grape juices (V. labrusca L.) and assessed the effect of drying process on the anthocyanins content and microstructure of this residue. Residue samples were subject to convective drying and the process kinetics was modeled using four semi‐empirical models. The Page model was selected as the best‐fit model obtaining the lowest chi‐square values (χ2 &lt; 0.000733). The effective diffusivity values ranged from 9.08 × 10−4 to 1.52 × 10−3 m2/s and the activation energies values were 23.06 and 20.89 kJ/mol for organic and conventional residues, respectively. The drying rate was augmented by increasing temperature with maximum values at 65 °C, for which the micrographs revealed the formation of smaller particles in samples when compared with drying at 45 and 55 °C. The conventional residue showed the highest levels of anthocyanins, which were consistently decreased with temperature as function of time, indicating that those are critical parameters for technological applications of this polyphenol‐rich matrix.Practical applicationsThe clarification process is an important technological stage for processing of fruit juices. Grape juices are widely appreciated worldwide and the accumulation of viticulture by‐products is a current concern in many producing regions. There is a global demand for reducing organic waste in food industries and alternatives for reutilization of plant materials emerge as a rewarding alternative to produce food ingredients. The non‐pomace residue of grape juices is a solid and highly‐colored material rich in polyphenols that is continuously discarded and currently unexplored. The study of its chemical properties as well as the use of drying processes to allow its technological application provides an important solution in order to achieve waste reduction in viticulture and discovering new matrices as sources of bioactive polyphenols.

Silver Nanoparticle-Based Fluorescence-Quenching Lateral Flow Immunoassay for Sensitive Detection of Ochratoxin A in Grape Juice and Wine.

A silver nanoparticle (AgNP)-based fluorescence-quenching lateral flow immunoassay with competitive format (cLFIA) was developed for sensitive detection of ochratoxin A (OTA) in grape juice and wine samples in the present study. The Ru(phen)-doped silica nanoparticles (RuNPs) were sprayed on the test and control line zones as background fluorescence signals. The AgNPs were designed as the fluorescence quenchers of RuNPs because they can block the exciting light transferring to the RuNP molecules. The proposed method exhibited high sensitivity for OTA detection, with a detection limit of 0.06 µg/L under optimized conditions. The method also exhibited a good linear range for OTA quantitative analysis from 0.08 µg/L to 5.0 µg/L. The reliability of the fluorescence-quenching cLFIA method was evaluated through analysis of the OTA-spiked red grape wine and juice samples. The average recoveries ranged from 88.0% to 110.0% in red grape wine and from 92.0% to 110.0% in grape juice. Meanwhile, less than a 10% coefficient variation indicated an acceptable precision of the cLFIA method. In summary, the new AgNP-based fluorescence-quenching cLFIA is a simple, rapid, sensitive, and accurate method for quantitative detection of OTA in grape juice and wine or other foodstuffs.

Inhibiting and Inactivating Effect of Chitosan on Heat Resistant Moulds Responsible for Spoilage of Pasteurized Fruit Products

The antimicrobial properties of chitosan, a deacetylated derivative of chitin, were assessed in a synthetic medium and in a blueberry and red grape juice against six heat resistant moulds (HRM) associated with food spoilage, in order to evaluate its use as a potential food preservative of natural origin. In both synthetic medium and natural substrate, the Minimum Inhibitory Concentration (MIC) of chitosan proved to vary in a wide range, regardless to both fungal genus and medium considered. Although Aspergillus neoglaber, Talaromyces bacillisporus and Aspergillus niger proved most resistant to chitosan (MIC > 5000 mg/L) on both media, a marked difference was detected for other strains tested. On HRM inoculated in MEB, the MIC was equal to 100 mg/L for Byssochlamys fulva or Monascus floridanus, and to 1000 mg/L for Talaromyces macrosporus. On HRM inoculated in blueberry and red grape juice, the MIC was equal to 2500 mg/L for Byssochlamys fulva or Monascus floridanus, and to 5000 mg/L for Talaromyces macrosporus. If combined with thermal treatment (80°C for 5 min) at a concentration (500 mg/L) that did not prove effective in inhibiting fungal spores, chitosan did not affect spore survival of microorganisms tested, thus allowing the spoilage of tested fruit juice after 5 days at 30°C. Also heat resistance parameters of a selected heat-resistant strain, T. bacillisporus, were not significantly affected by supplementation of blueberry and red grape juice with 500 mg/L of chitosan, D values ranging between 47.6 and 71.4 minutes at 82°C; 13.3 and 23.3 minutes at 85°C; 3.6 and 5.9 minutes at 88°C; 0.9 and 1.8 minutes at 91°C (z=5.2°C to 5.5°C). Since chitosan did not prove effective alone or combined with thermal treatment either to inactivate heat resistant microorganisms tested or to modify heat-resistance parameters of a heat resistant mould such as T. bacillisporus, its use cannot be considered as an interesting strategy to apply milder thermal treatments and to achieve stability of acid products.

Determination of total antioxidant activity of fruit juices widely consumed in Syria

Fruits are considered essential constituents of a healthy diet. They possess antioxidant properties which can be attributed mainly to their phenolic compounds. Two samples of the following fruit juices (orange, grapefruit, blackberry, black mulberry, black sweet cherry, strawberry, pomegranate, organic tomato, greenhouse tomato, black plum, black grape and red grape) were investigated for their phenolic content and total antioxidant activity. Total phenolic content was determined according to Folin-Ciocalteu method. Black mulberry juice showed the highest results with amounts from 8.6gGAE/Ljuice to 11.2gGAE/Ljuice, while the lowest was red grape juice with amounts from 0.3 gGAE/Ljuice to 0.7gGAE/Ljuice. Total Antioxidant activity was subsequently determined using Ferric Reducing Antioxidant Power (FRAP) assay and reducing power assay. The results were in accordance with Folin-Ciocalteu method since black mulberry juice had the highest antioxidant power, while red grape juice had the lowest. The study indicates that black mulberry juice is the richest source of phenolic compounds and provides the highest antioxidant potential compared with other fruit juices in this study. Reducing power assay gave a similar order compared to FRAP assay. Both assays depend on reducing the ferric complex to its ferrous form which could explain the similarity in juice order considering their antioxidant activity.