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Effect of the Use of Ground Flaxseed on Quality and Chemical Composition of Bread
Effects of ground flaxseed on bread quality, staling, and in particular on -tocopherol and unsaturated fatty acid composition were determined. Ground flaxseed was added in concentrations of 10, 15, 20, and 25% to wheat flour sample. Results showed that the use of ground flaxseed at a 10% level markedly increased loaf volume, specific loaf volume, Dallman degree and retarded bread staling. Oil and -tocopherol content and proportion of linolenic acid in fatty acid composition went up as the ratio of flaxseed flour in bread formulation was increased. Oil, -tocopherol content, and proportion of linolenic acid in fatty acid varied in the range of 1.48—8.20%, 0.2—0.24 g/kg sample oil, and 50.25—55.55%, respectively in breads enriched with flaxseed flour. During bread staling, the change in peroxide values, -tocopherol content, and fatty acid distribution were not significant. Bread samples were tested for crust color appearance, crumb color, shape-symmetry, external appearance, mouth feel, and taste-aroma. The general acceptability was good at the level of 15% flaxseed flour addition and other substitute levels were found satisfactory.
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Effects of Mandarin Cultivar on Quality of Mandarin Juice
Eight mandarin cultivars have been analyzed for their content of vitamin C, minerals (Ca, Mg, K, Na, Fe, Cu, Mn, and Zn), CIELab color coordinates (L*, a*, b*, C*, and h ab), total volatile compounds content and sensory aroma intensity of juice. Experimental results proved that no important enough differences were found in the minerals contents to decide which mandarin cultivar was of higher quality. Clemenules provided the darkest juice with the highest vitamin C content and with the most intense mandarin aroma. On the other hand, Nova and Hernandina mandarin could be considered as the worst cultivars for juice production. Finally if Clemenules mandarins were not available for juice processing, Orogrande, Clemenpons, Ellendale, and Marisol could also be good options.
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Visual Detection of Calcium by GBHA Staining in Bitter Pit-affected Apples
Bitter pit is a physiological disorder of apple fruits apparently caused by a localized calcium deficiency or imbalance in fruits associated with low levels of calcium in the flesh. A new, highly selective method using glyoxal bis(2-hydroxyanil, GBHA) was tested to reveal the presence of calcium within the fruit as a red stain. Water-soluble and insoluble calcium was analyzed by capillary electrophoresis and atomic absorption spectroscopy in pitted regions, adjacent sound areas and pulp from sound apples. Both methods, selective calcium staining and mineral analysis, showed that calcium accumulates in the pitted areas of apples affected by bitter pit. However, in mechanically inflicted wounds, the pulp of the apple was heavily stained but not the corresponding fingerprint, indicating a similar mechanism of insoluble calcium accumulation but a different distribution of soluble calcium compared to the pits.
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Rheological Characteristics of Juniperus drupacea Fruit Juice (pekmez) Concentrated by Boiling
Rheological parameters of Juniperus drupacea fruit pekmez were evaluated using a rotational viscometer at 10, 20, 30, 40, and 50 °C and at concentrations of 62.8, 68.9, 72.0, and 75.2% total soluble solids. The flow characteristics of Juniperus drupacea fruit pekmez were described by the power law and Herschel—Bulkley models. The Herschel—Bulkley model was found to be the best to describe the rheological property with the coefficient of determination higher than 0.993. Juniperus drupacea pekmez exhibited a time-independent shear thickening behavior. The effect of temperature on viscosity can be described by means of an Arrhenius equation. Depending on the soluble solid contents, the activation energies for flow of diluted samples vary from 78.23 to 60.38 kJ/mol. The effect of soluble solids on viscosity can be described by an exponential equation. Experimental data were fitted to several models in order to describe the effect of temperature and soluble solid content. The combined effect of temperature and soluble solid content on viscosity was also formulated.
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Aromatic Constituents from Chinese Traditional Smoke-cured Bacon of Mini-pig
Volatile composition of Chinese traditional smoke-cured bacon of Mini-pig breed was first characterized. Both headspace solid phase microextraction (SPME) and simultaneous distillation and solvent extraction (SDE) were performed. SDE exhibited efficiency in the extraction of representative aromatic volatiles especially the phenolic smoky flavors from the bacon sample. In total, 104 different components were found with the major quantity and kinds of aromas being the volatile saturated and unsaturated aldehydes from lipid oxidation and the phenolic compounds from smoke. Olfactory evaluation (GC-O) of the SDE extract revealed five basic odor patterns pertaining to 53 odor active regions and 47 odorants. Some key flavors accounting for the bacon aroma were (E, E)-2, 4-decadienal, 3-(methylthio) propanal, 2-furanmethanol, guaiacol, 3-ethylphenol and 2, 5-dimethylpyrazine.
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Volatile and Glycosidically Bound Composition of Loureiro and Alvarinho Wines
Composition of Loureiro and Alvarinho wines from the Vinhos Verdes region, regarding free volatile compounds as well as glycosidically bound aroma precursors, was exhaustively determined by gas chromatography—mass spectrometry after adsorption on XAD-2 resin. On the whole, were identified and quantified 120 volatile compounds in the free fraction and 77 glycosidically bound compounds, belonging to C6-compounds, alcohols, fatty acids ethyl esters, esters of organic acids, acetates, monoterpenic alcohols, monoterpenic oxides and diols, C13-norisoprenoids, volatile phenols, volatile fatty acids, and carbonyl compounds. Globally, the wines of the two cultivars present similar composition on volatiles. However, regarding varietal compounds, Loureiro wines were richer than Alvarinho ones with respect to C6-compounds and monoterpenic compounds, occurring the opposite for volatile phenols. It was also demonstrated that wines of both varieties might benefit the aroma reserve, present as glycoconjugates, as it is susceptible of being technologically explored. Linalool, Ho-trienol, (-terpineol, contributing with fruity and floral notes, and (β-damascenone mostly for Alvarinho, confering tropical fruit notes, are the varietal compounds which may particularly influence the aroma of these wines. Respecting fermentative compounds, Alvarinho is also particularly rich in fatty acids ethyl esters related to lipid metabolism and acetates of fusel alcohols, which can provide it a fruity character; Loureiro contains higher levels of esters of organic acids and 2-phenylethanol, conferring fruity and floral notes. Sensory analysis agreed with chemical analyses showing a pronounced tree and tropical fruit character for Alvarinho wines while Loureiro wines present more intense citrus fruit notes.
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Quality Characteristics, Respiration Rates, and Microbial Stability of Osmotically Treated Mango Tissue (Mangifera indica L.) with or without Calcium Lactate
Mango minimally processed (20 °Brix) was obtained by applying osmotic treatments and the product quality development was evaluated throughout storage. Osmotic treatments were carried out at atmospheric pressure Osmotic dehydration (OD) and by applying a vacuum pulse osmotic dehydration (PVOD) using 45 °Brix sucrose solutions with and without calcium lactate (2%). Mechanical properties were measured after treatments and after 10 days storage. Color, microbial controls, and respiration rates were measured throughout storage time, in order to evaluate the development of the different parameters which affect product quality. Osmotic treatments induced changes in the physical properties, respiration rates and microbial behavior, depending on the treatment conditions and the addition of calcium lactate. From the microbiological point of view the most stable samples are those treated with calcium in both OD and PVOD treatments. Respiration rates were also reduced to a greater extent in these treatments. Mechanical properties are also better preserved when calcium is applied in PVOD treatments. Nevertheless, a greater decrease in hue is observed in calcium treated samples which indicates that browning occurs more intensely in these cases.
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Influence of Gamma Irradiation on Microbiological, Biochemical, and Textural Properties of Bonito (Sarda sarda) During Chilled Storage
This study evaluates the influence of various doses of gamma irradiation on some quality aspects of iced bonito (Sarda sarda). Fresh bonito sections were aerobically packed and gamma irradiated with doses of 0, 1.5, 3, 4.5, 6, and 7.5 kGy, samples were then chilled during 21 days. Microbiological analyses showed the presence of mesophilic and psychrophilic germs just before irradiation treatment. These germs were eliminated at doses ≥1.5 kGy. The analyses of total volatile basic nitrogen (TVB-N), trimethylamine (TMA) as well as the texture analysis showed that irradiated samples preserved a good quality during 21 days of chilled storage, whereas the control showed putrefaction. Histamine content was reduced after irradiation treatment, such decrease strongly correlated with the applied dose level. Fatty acid composition survey demonstrated that gamma irradiation associated with aerobic packaging influenced significantly the lipid profile. Irradiation at doses of 6 and 7.5 kGy reduced significantly poly-unsaturated fatty acid fraction. Results demonstrated that irradiation amplified the rate of lipid oxidation as shown by an increased peroxide value especially at higher doses. Gamma irradiation at low doses was effective in extending the bonito's shelf-life through the improvement of its microbiological, biochemical and textural qualities up to 21 days of chilled storage.
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Nutritional Quality and Antioxidant Activity of Selected Edible Wild Mushrooms
Five species of edible wild mushrooms were selected to determine the proximate composition, vitamins (retinol, -tocopherol, -tocopherol, thiamin, riboflavin, and ascorbic acid) and mineral contents (Fe, Zn, Co, Ca, Mg, K, and Na), antioxidant activity, and total phenolics. Hygrophorus sp. showed significant higher ( p<0.05) fat content as compared to other wild mushrooms with the mean value of 6.57%. However, Polyporus tenuiculus was found to be a good source of fiber while Hygrocybe sp. was good in -tocopherol among the mushrooms tested. The iron and calcium contents were the highest in Hyrocybe (175.64 µg/g) and Hygrophorus sp. (81.70mg/100g) respectively. The in vitro antioxidant activities of petroleum ether (PE) and methanolic extracts of the edible wild mushrooms were comparable to the cultivated oyster mushroom. The radical scavenging activity was highest for PE extract of Pleurotus sp. (85%) while methanolic extract of Hygrocybe sp. exhibited the highest (94%) chelating effect, in correlation with its significantly higher ( p<0.05) phenolics content (42.21 mg GAE/g extract). In conclusion, edible wild mushrooms can be an excellent source of micronutrients and antioxidant components.
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Cell Wall Physicochemical Properties as Indicators of Peach Quality During Fruit Ripening after Cold Storage
A comparative study between melting flesh peach fruit (Prunus persica L. Batsch cvs. Royal Glory and Morettini No 2) with contrasting tissue firmness during their on-tree ripening was conducted. Such fruit were cold stored (0 °C) for 4 and 6 weeks, and subsequently transferred at 25 °C (shelf life) for up to 5 days and evaluated for quality attributes and cell wall physicochemical properties. Data were partly unexpected, since fruit of the soft cultivar (Morettini No 2) were characterized by lower exo- and endo-PG activity, lower amounts of ethylene evolution, as well as higher amounts of endogenous calcium bound in the cell wall compared to fruit of the firmer cultivar (Royal Glory). These differences may be attributed to the incidence of chilling injury symptoms, evident as loss of juiciness in Morettini No 2 fruit, while Royal Glory fruit were characterized by acceptable appearance and eating quality even after 6 weeks cold storage plus 5 days shelf life, as the fruit softened gradually without cell rupture. Overall results showed that no direct relationship between cell wall physicochemical properties and sensory attributes can be established, indicating the complexity of peach fruit ripening. Since fruit of both cultivars presented similar tissue firmness after 5 days shelf life an attempt to distinguish normal peach fruit softening from cell rupture-chilling injury also has been made in the current study.
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