High‐pressure high‐temperature extraction of phenolic compounds from grape skins

This study focused on the use of a non‐conventional extraction technology by employing high‐pressure high‐temperature stirred reactor to extract polyphenols from grape skins. Extraction time (15–330 min) and temperature (30–150 °C) were selected as independent variables, and their effects were studied. A preliminary kinetic study on polyphenols extraction revealed that the second‐order model fitted satisfactorily the experimental results (R² ≥ 0.9798). Total polyphenol yield and total flavonoid (TF) yield, as well as the antiradical power (ARP) of the extracts, were analysed. The use of high‐pressure high‐temperature technology resulted in obtaining extracts rich in polyphenols with high ARP. The highest total polyphenol (60.7 mg_GAE ) and TF (15.1 mg_CE ) yields were obtained at 150 °C for 270 min and 150 °C for 15 min, respectively. HPLC was employed to analyse phenolic compounds. Considerable quantities of single phenolic compounds were extracted. The highest yields of gallic acid, 5‐hydroxymethylfurfural, protocatechuic acid, catechin, vanillic acid, syringic acid, cumaric acid, trans‐resveratrol and quercetin (163.2, 20.0, 69.9, 420.0, 20.6, 603.0, 20.1, 42.4 and 117.1 mg per 100 g_DS, respectively) were found. ARP values were found between 8.45 and 52.17 μg_DPPH .     

Flavonoid constituents and their contribution to antioxidant activity in cultivars and hybrids of rabbiteye blueberry (Vaccinium ashei Reade)

Fruit from 42 blueberry (Vaccinium spp.) cultivars, including 36 rabbiteye cultivars (Vaccinium ashei Reade), three V. ashei hybrid derivatives, and three northern highbush (Vaccinium corymbosum L.) standards were evaluated for antioxidant capacity, individual flavonoid content, and the contribution of each identified phenolic compound to total antioxidant activity. Considerable variation was found in flavonoid content, antioxidant activity, and their contribution to total antioxidant activity among cultivars. Among 42 blueberry cultivars, the rabbiteye ‘Early May’ contained the highest amount of chlorogenic acid, myricetin 3-arabinoside, quercetin derivatives, and delphinidin-, cyanidin-, petunidin-, and malvidin-basis anthocyanins. ‘Early May’ cultivar also had the highest antioxidant activity (88.2 μmol TE/g fw). ‘Owen’, ‘Bluegem’, ‘Clara’, Climax’, and ‘Centurion’ were among the other rabbiteye cultivars that also had high levels of flavonoids and antioxidant activities. In contrast, the pink-fruited V. ashei hybrid, ‘Pink Lemonade’, had the lowest content of flavonoids and lowest antioxidant activity. The mean flavonoid content and antioxidant activity of rabbiteye cultivars was higher than those among northern highbush and V. ashei hybrids. The antioxidant activity of V. ashei hybrid derivatives was derived mainly from chlorogenic acid, myricetin, and quercetin, which contributed 62.5% of total antioxidant activity, whereas anthocyanins (malvidin, petunidin, delphinidin, and cyanidin) were the main contributors to the antioxidant activity of rabbiteye cultivars (76.2%) and northern highbush standards (76.8%). Blueberry cultivars identified to have high phenolic content and high antioxidant activity could be used as parents for future blueberry breeding programmes to develop new blueberry cultivars with higher antioxidant activity and further improve human health.     

Use of thiamine for controlling Alternaria alternata postharvest rot in Asian pear (Pyrus bretschneideri Rehd. cv. Zaosu)

The effects of thiamine (vitamin B₁) against Alternaria rot caused by Alternaria alternata and its possible mechanism in harvested Asian pear fruit were investigated. Thiamine strongly inhibited spore germination and mycelial growth of A. alternata in vitro. Thiamine at a concentration of 100 mm effectively inhibited the development of Alternaria rot, enhanced the activities of defence‐related enzymes, such as phenylalanine ammonia‐lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD), and increased the content of flavonoids, phenolics and lignin. Thiamine also affected reactive oxygen metabolism of the pear fruit by increasing its production and H₂O₂ content, and enhancing the activities of major detoxifying enzymes, such as superoxide dismutase (SOD). These findings suggest that the effects of thiamine on Alternaria rot in pear fruit may be associated with its direct fungitoxic property against the pathogens, and the elicitation of biochemical defence responses in the fruit.     

Fracture properties of potato crisps

The Weibull modulus of potato crisps is about 4, comparable with ceramic materials, with a characteristic strength of about 1.5 MPa. This combination of brittleness and weakness gives crispness. The critical stress intensity factor (K_IC) and the energy of fracture (R) are around 0.12 MPa and 45 J m^–2, respectively. There was no significant difference between the material values obtained for the fracture properties of crisps of a range of subjective ‘crispness’ as measured by a trained organoleptic panel. Crispness is ranked by the structural bending strength. Centrally loaded plate tests give qualitative evaluation of crispness. Both these tests could be used in quality control, with advantage over organoleptic tests such as cost, the time required, objectivity, consistency of results, the relation of the measured parameters to standard materials tests and the relatively small amount of material that is needed by comparison.     

Glass Transition Study in Model Food Systems Prepared with Mixtures of Fructose,Glucose, and Sucrose

Abstract: The glass transition temperature of model food systems prepared with several glucose/fructose/sucrose mass fractions was studied using differential scanning calorimetry (DSC). A distance‐based experimental design for mixtures of 3 components was used to establish the proportion of sugars of the model systems. Thus, 32 compositions including individual sugars and sugar mixtures, both binary and ternary were prepared and analyzed. Thermograms showing the complete process of heating–cooling–reheating were used to determine the precise glass transition temperature during cooling () or reheating () in amorphous sugars. The Scheffe cubic model was applied to experimental results to determine the influence of sugar composition on the glass transition temperature (P < 0.05). The final model proved to be appropriate (R² > 0.97, CV < 9%, model significance <0.0001) to predict the T_g values of any dry mixture of amorphous fructose, glucose, and sucrose. Practical Application: The experimental values of T_g and the mathematical model proposed in this work may be of great use for making available T_g data that involves the mixture of more than 2 sugars and thus could be used as a tool for predicting the storage stability and quality of dehydrated products such as fruit powders.     

Antioxidant anthocyanins screening through spectrum-effect relationships and DPPH-HPLC-DAD analysis on nine cultivars of introduced rabbiteye blueberry in China

Blueberries have drawn growing attention in China for various benefits to health. Nine rabbiteye blueberry cultivars which were introduced into China were systematically assessed based on two aspects of chemical profiles and antioxidant activity. The former was achieved by HPLC fingerprints, and the latter in terms of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging capacity was evaluated with a novel HPLC method. Subsequently, the predominant active anthocyanins were screened from these coloured biological samples by two useful methods, respectively. In method I, the spectrum-effect relationships between HPLC fingerprints and the antioxidant activities of blueberry extracts were investigated, whereas in method II, HPLC analysis followed pre-column reaction of samples with DPPH. The results indicated that Gardenblue and Powderblue showed stronger antioxidant activities among all introduced cultivars, and delphinins and anthocyanidin-3-glucosides were the main contributive components to the antioxidant activities of blueberries. This would be helpful to the quality-oriented cultivation of blueberry in China.     

Phenolic profile and changes in the antioxidant activity of crabapple (Malus domestica cv Royalty) fruit during maturation on the tree

The fruits of crabapple (Malus domestica cv Royalty) harvested at six times during fruit maturation on the tree (60, 80, 100, 120, 140 and 160 day after full bloom, DAFB) were evaluated for their antioxidant potentials by various assays such as DPPH, ABTS, superoxide anion, hydroxyl radical and ferric reducing power. Total phenolic and flavonoid were analysed and characterised using HPLC‐DAD‐MS/MS. Results showed that the Royalty fruits harvested on 60 DAFB had the strongest scavenging activity against DPPH, ABTS and radicals ( = 0.37 mg mL^?1,  = 0.19 mg mL^?1 and  = 4906.63 U L^?1) and ferric reducing power (FRAP = 2.85 mol Fe²⁺ per kg dw), which highly correlated with its high amount of total phenolics of 130.17 mg gallic acid equivalents (GAE) per gram dry weight and total flavonoid of 866.15 mg rutin equivalents (RE) per gram dry weight. Eight phenolic compounds were identified in the Royalty extract of 60 DAFB as caffeic acid, eriodictyol rhamnoside, phloretin hexoside I, coumaroyl guinic acid, quercetin hexoside, phloretin hexoside II, quercetin pentoside and quercetin rhamnoside. These findings suggest that Royalty could be potentially used as a promising source of natural antioxidants in the development of functional foods.     

PREDICTION OF THE TEXTURE OF COOKED POULTRY PECTORALIS MAJOR MUSCLES BY NEAR-INFRARED REFLECTANCE ANALYSIS OF RAW MEAT

Near‐infrared reflectance (NIR) spectra were collected on pectoralis major muscles from 90 broiler carcasses ( from 2 different processing sets) to assess the relationship between the NIR and a cutting‐shear instrumental texture test. For the instrumental razor blade test, two instrumental parameters (maximum shearing force and total shear energy) were calculated. Calibration (R²) and validation () coefficients of determination were obtained for predicting the instrumental measurements using the reflectance and its first and second derivatives. Models obtained with the second derivative were adequate when the two groups of samples were analyzed separately. The R² values ranged from 0.90 to 0.95 and from 0.84 to 0.89 for both maximum shear force and total shear energy. The regressions performed on the two sample sets combined did not yield model statistics that were as satisfactory (R² = 0.85–0.86 and = 0.78–0.77), suggesting that a prediction model accurately predicting poultry breast meat tenderness will need a larger and more varied sample set. The results suggest that NIR could be used to predict poultry meat texture and to classify muscles according to tenderness levels.     

Gamma radiation effect on quality changes in vacuum‐packed squid (Illex argentinus) mantle rings during refrigerated (4–5 °C) storage

The effect of gamma radiation (0, 1.8, 3.3 and 5.8 kGy) on microbiological, chemical and colour characteristics of vacuum‐packed squid (Illex argentinus) mantle rings was studied. Total viable counts; psychrotrophic bacteria counts, Escherichia Coli, Staphylococcus aureus and Clostridium perfringens; total volatile basic nitrogen (TVBN) and colour difference were analysed during 29 days of storage at 4–5 °C. Higher doses of gamma radiation significantly reduced Total Viable, phychrotrophic counts and TVBN production (P < 0.05) in a dose‐dependent way, delaying squid spoilage. Colour difference of non‐irradiated samples with respect to first day significantly increased while it was constant in radiated samples during 22 days (P < 0.05). Independently from the dose, radiation avoided colour changes of squid rings. Gamma irradiation was effective in delaying deterioration reactions, improving microbiological, chemical and colour quality of vacuum‐packed squid rings stored at 4–5 °C.     

VISCOSITY CHARACTERIZATION OF A COMMERCIAL YOGURT AT 5C USING A CUP IN BOB AND A VANE GEOMETRY OVER A WIDE SHEAR RATE RANGE (10−5S−1-103s−1)

Equilibrium viscosity data at 5C, over a wide shear rate range (10^?5 s^?1 -10³ s^?1), are presented for a typical commercially available stirred yogurt. A bob in cup and a vane in cup geometry were used in the work. The vane was manufactured to the same outer dimensions as the bob. A series of constant shear stress creep tests was performed, ranging from 2 Pa to 60 Pa. Equilibrium shear rate values were found for each shear stress. Equilibrium viscosity data obtained with both geometries were of the same order of magnitude. This indicated that slip (wall depletion) effects were not significant with the bob in cup geometry used in the study. Application of existing rheological models showed that the equilibrium viscosity behavior of yogurt may be described using either a power-law of the form or the Cross equation The Cross model better predicted the almost constant viscosities observed at low shear stresses.     

Variation in antioxidant enzyme activities and nonenzyme components among cultivars of rabbiteye blueberries (Vaccinium ashei Reade) and V. ashei derivatives

Fruit from 42 blueberry (Vaccinium species) cultivars, including 36 rabbiteye cultivars (Vaccinium ashei Reade), 3 V. ashei hybrid derivatives and 3 northern highbush (V. corymbosum L.) standards, were evaluated for antioxidant activities (AA), levels of antioxidant enzymes [catalase (CAT), ascorbate peroxidase (AsA-POD), glutathione reductase (GR), glutathione peroxidase (GSH-POD), superoxide dismutase (SOD), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDAR) and guaiacol peroxidase (G-POD)], and antioxidant nonenzyme components [ascorbic acid (ASA) and glutathione (GSH)]. The results of this study showed that cultivars had varying levels of AA, a wide range of antioxidant enzyme activities and various amounts of nonenzyme components. The correlations between AA and all of the enzyme activities or nonenzyme components were positive and high in the 42 cultivars tested in this study. The correlation (R²) values between AA and CAT, SOD, DHAR, MDAR, GSH-POD, GR, G-POD and AsA-POD were 0.91, 0.91, 0.91, 0.91, 0.90, 0.90, 0.90, and 0.90, respectively. The correlations between AA and ASA and GSH were 0.94 and 0.92, respectively. Among all 42 cultivars, ‘Early May’ had the highest activities of the AA, AsA-POD, G-POD, DHAR and MDAR and the highest amounts of ASA and GSH, whereas ‘Elliott’ had the highest levels of GR, GSH and SOD.     

Effect of Iberian × Duroc genotype on composition and sensory properties of dry‐cured ham

BACKGROUND: Dry‐cured ham quality from three different Iberian × Duroc genotypes was studied: GEN1, Iberian × Duroc1; GEN2, Duroc1 × Iberian; GEN3, Duroc2 × Iberian. GEN1 and GEN2 are reciprocal crosses, while the difference between GEN2 and GEN3 is the Duroc sire line. The line Duroc1 (DU1) was selected for the manufacture of dry‐cured meat products, whereas the line Duroc2 (DU2) was selected for meat production with low carcass fat. RESULTS: Dry‐cured hams from all genotypes had similar chemical composition. However, intramuscular fat of dry‐cured hams from GEN3 was more unsaturated than that from GEN2, while GEN1 was intermediate. Lipid oxidation, measured as 2‐thiobarbituric acid‐reactive substances (TBARS) and hexanal content, was similar between genotypes. The colour of hams was affected by genotype; hams from GEN2 showed higher lightness (CIE L*), while those from GEN3 had a less intense colour (lower a* and C*). Texture measured instrumentally did not differ between genotypes; however, in the sensory analysis, panellists considered hams from GEN3 more fibrous, while those from GEN2 were considered juicier. Hams from GEN3 were also perceived as saltier and more acid. CONCLUSION: Genotype affected the quality of Iberian hams, with those from GEN3 being of lower quality, and this genotype was considered less suitable for the manufacture of Iberian dry‐cured ham. Copyright © 2007 Society of Chemical Industry     

Genotype and growing season influence blueberry antioxidant capacity and other quality attributes

Forty‐two blueberry cultivars (thirty‐six Vaccinium ashei, three V. ashei derivative hybrids and three northern highbush standards) were evaluated for their antioxidant capacities and other fruit quality attributes over two growing seasons. Total anthocyanins, phenolic content and antioxidant capacities varied substantially among species and cultivars. ‘Early May’ (V. ashei) had the highest amounts of anthocyanins, phenolics and antioxidant capacity. Cultivars from V. ashei hybrid derivatives had lower mean antioxidant components than those from northern highbush standards or V. ashei. The antioxidant capacity, as well as total anthocyanins and phenolics, had significant cultivar × year interactions. Correlation coefficient between years for total anthocyanins, total phenolics and oxygen radical absorbance capacity were high with values of 0.86, 0.81 and 0.93, respectively. Similar interactions were observed for soluble solids content (SSC), sugar, titratable acid and organic acids among cultivars both within and across the growing seasons. Correlation coefficients between years for SSC, fructose, glucose and sucrose were 0.78, 0.71, 0.83 and 0.96, respectively. Fructose and glucose were detected as two major sugars with sucrose as a minor constituent. ‘Clara’ contained the highest amounts of SSC and sugars, while ‘Satilla’ had the lowest. In general, V. ashei cultivars had a higher mean SSC and sugar contents than did the hybrid derivatives or the northern highbush standards. Cultivars of V. ashei contained higher malic acid than citric acid, whereas in hybrid derivatives and northern highbush cultivars, citric acid was the predominant organic acid. The diversity in the amount of these fruit quality attributes and antioxidant capacities presents a great opportunity for genetic improvement of blueberries through breeding programmes. The objective of the study was to identify blueberry cultivars with high antioxidant activity and good fruit quality, so they can be used as parents for future blueberry breeding programmes to develop new cultivars with higher antioxidant activity.     

Adhesion,Cohesion, and Friction Estimated from Combining Cutting and Peeling Test Results for Thin Noodle Sheets

The aim of this study was to estimate the adhesive and cohesive fracture energies, and frictional characteristics of 7 types of cooked starch and flour sheets and combine these into a model framework for textural analysis. Cutting tests with wires of diameter 0.30 to 0.89 mm were performed with and without lubrication. Plots of the work done, normalized to the area cut by the wire, showed that this to be linearly related to wire diameter irrespective of lubrication. The oil had little impact on the intercept of these plots, giving cohesive fracture energy (G_c) ranges for these foods between 6.8 and 32.5 J/m². However, lubrication had a strong influence on the slope of the plots. From a comparison of the slopes for lubricated versus unlubricated tests, the kinetic coefficient of friction could be calculated. Values for between 0.007 and 0.521 for different foods were obtained. Peeling tests were performed by lifting sheets vertically away from a fresh mica surface. The adhesive fracture energy G_a, varied from 2.5 to 4.8 J/m². The results can be modeled by plotting the ratio of cohesive to adhesive fracture energy against the coefficient of friction. Thresholds in both axes suggest a physical basis for distinguishing textural perceptions. However, sensory testing with 12 subjects using the 7 food types could not establish whether this framework, however well‐established physically, would apply to oral sensations. A much larger test would be required.     

Free radical scavenging activity of porcine plasma protein hydrolysates determined by electron spin resonance spectrometer

A study was conducted to investigate the antioxidant capacity of porcine plasma protein before and after enzymatic hydrolysis. Porcine plasma protein was hydrolyzed by using Alcalase with degree of hydrolysis (DH) ranged from 0 to 17.8%. The free radical scavenging effects of porcine plasma protein hydrolysates (PPH) were evaluated by electron spin resonance (ESR) spectrometer. The reducing power of PPH increased with increasing of DH (P < 0.05). The 5-h PPH exhibited the strongest inhibition of lipid oxidation, as indicated by lowest thiobarbituric acid-reactive substance values in a liposome-oxidizing system, and the strongest free radical scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), hydroxyl (OH) and superoxide (O₂-) radicals. The increase of protein concentration enhanced (P < 0.05) free radical scavenging effect of PPH. Although non-hydrolyzed plasma protein displayed an antioxidative effect, it was far less potent than PPH. The results indicated that the antioxidant capacity of porcine plasma protein could be enhanced by enzymatic hydrolysis of Alcalase.     

Cover Image,Volume 98, Issue 9

The cover image, by Noorani Barkat et al., is based on the Research Article Effect of harvest time on the levels of phytochemicals, free radical‐scavenging activity, α‐amylase inhibition and bile acid‐binding capacity of spinach (Spinacia oleracea), DOI: 10.1002/jsfa.8862 .

     

Fast Determination of Spatially Localized Volume Fractions in Emulsions

A rapid, noninvasive method for determining spatially resolved magnetic resonance (MR) spin-lattice relaxation rates (1/T₁) was developed to study the dynamics of emulsions. The technique acquires data simultaneously along the entire emulsion profile. The observed relaxation rates (1/T_1(obs)) for oil/water emulsions followed the equation: where Volume fractions along the profile of a 40% (v/v) oil/water emulsion were calculated for several times during creaming to establish dynamics of the process. Separation velocities calculated from such profiles may be used to test (or correct) predictions of models for creaming emulsions.     

Antioxidant effects of Origanum majorana L. on superoxide anion radicals

A purified compound with antioxidant properties (28 mg), T3b, was isolated from a methanol extract (10 g) of Origanum majorana L. by sequential procedures, with silica gel column, thin-layer, and LH-20 Sephadex gel column chromatographies. The in vitro scavenging activity of T3b on superoxide anion radical (O₂⁻) was investigated and compared to those of seven commercially available synthetic or natural antioxidants. Of those, the strongest scavenging action was observed in T3b with an IC₅₀ of 1.44 μg/ml. The T3b also exhibited significant inhibitory effects on 12-O-tetradecanolyphorbol-13-acetate (TPA)-induced O₂⁻ generation and hydrogen peroxide formation in differentiated HL-60 cells, indicating that the isolated compound is a potent chemopreventer. The purified compound from O. majorana L. was shown to possess both O₂⁻ scavenging activity and an inhibitory effect against TPA-induced O₂⁻ generation.