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Browning Index (browning + index)
Selected AbstractsKinetics of Potato Color and Texture Development during Baking, Frying, and Microwaving with the Addition of Liquid SmokeJOURNAL OF FOOD SCIENCE, Issue 9 2006M. Yost ABSTRACT:, The rate of color and texture development in par-fried French fries coated with liquid smoke and thermally processed was determined. Liquid smoke containing 8% to 11% carbonyls was diluted to 30% and applied to 1 side of French fries at 0%, 1%, 3%, or 5% by weight. The fries were immersion fried at 190.6 °C for 4 min, microwaved (900 watts) for 4 min, or baked at 190.6 °C for 20 min. Color and texture measurements were recorded at intervals during processing. Liquid smoke increased the rate of browning in French fries. Browning followed pseudo zero-order kinetics, with the a value, Browning index, and total change in color (,E) showing the best fit. When liquid smoke was added in high concentrations the reaction rate did not increase as more liquid smoke was added because the carbonyls were no longer limiting the rate of Maillard browning. The rate of color development in French fries was also affected by the thermal processing method. Frying developed color at the fastest rate, followed by microwaving and baking. Although liquid smoke increased the rate of color development in French fries, it did not affect French fry texture. Through sensory testing, it was determined that liquid smoke can be used to improve the color of microwaveable French fries without affecting French fry flavor or texture. [source] Degradative enzymatic activities in fresh-cut blood-orange slices during chilled-storageINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2009Anna Eghle Catalano Summary Blood-orange fruits are suitable to fresh-cut fruit production because of their chemical compositions. Nevertheless, the main limitation of using freshly cut oranges is their susceptibility to juiciness loss and ascorbic acid degradation because of enzymatic alterations. The aim of this work is: to identify some of the enzymes causing the qualitative decay in blood-orange slices during 15 days of chilled storage (at 4 ± 0.5 °C and 85% RH); to investigate the susceptibility to the previous alterations of five blood-orange clones (Moro nucellare, Sanguinello nucellare, Tarocco arcimusa, Tarocco gallo and Tarocco meli) to select the most suitable one for fresh-cut production. The enzymes studied were: pectinmethylesterase (PME) as index of juiciness loss, ascorbate oxidase (AAO) as index of ascorbic acid's degradation and polyphenol oxidase (PPO) as browning index. As far as we know, the changes of AAO activity during chilled storage of blood-orange fresh-cut slices has not previously reported and studied. Different clones showed different enzymatic activities and quality changes during chilled-storage. In particular a low juiciness loss in orange slices was correlated with a lower PME activity, as described in T. meli clone, while a high degradation of ascorbic acid was correlated with an higher AAO activity, as described in T. gallo clone; PPO activity seemed to have no significant action in quality degradation. Tarocco meli was the most suitable clone to the fresh-cut blood-orange production because it has the lowest enzymatic activity (PME, PPO and AAO) and the highest sensorial quality. [source] CHANGES IN MAJOR ANTIOXIDANT COMPOUNDS DURING AGING OF TRADITIONAL BALSAMIC VINEGARJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2010ELENA VERZELLONI ABSTRACT Traditional balsamic vinegar (TBV) shows antioxidant capacity that increases passing from cask 5, containing the youngest vinegar, to cask 1 containing the oldest vinegar. This increase in antioxidant capacity is a consequence of both the concentration of compounds already present and of new antioxidants formation and is positively related to the increase in the polyphenolic content and in the Maillard reaction/caramellization products. During TBV aging, some reactions involving flavonoids and tannins take place. Tannins can undergo acid-catalyzed cleavage of their interflavonoid bonds with subsequent condensation of other flavonoid molecules. In addition, the low pH, the decrease of the water content and the presence of aldehydes, may promote flavonoids polycondensation. These reactions explain the observed increase in polymeric phenolic compounds and the decrease in monomeric flavonoids. During TBV aging an increase in the browning index is observed as a consequence of the polycondensation reactions of flavonoids and of brown melanoidins accumulation. PRACTICAL APPLICATIONS Traditional balsamic vinegar is a potentially healthy seasoning with high antioxidant capacity that increases during the aging resulting in a product with a strong antioxidant capacity and rich in phenolic compounds such as phenolic acids, monomeric catechins, flavonols and tannins. It also contains other antioxidants such as melanoidins derived from the Maillard and caramelization reaction that occur during must boiling and traditional balsamic vinegar aging. Independently of their bioavailability, traditional balsamic vinegar can contribute to supply antioxidant molecules that play an important role in protecting the gastrointestinal tract itself against peroxidation, thereby limiting the formation of detrimental lipid degradation products. [source] POLYPHENOLOXIDASE ACTIVITY OF MINIMALLY PROCESSED ,JONAGORED' APPLES (MALUS DOMESTICA)JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2005A.M.C.N. ROCHA ABSTRACT The influence of three chemical dips using ascorbic acid (AA), citric acid (CA) and calcium chloride (CC) on the polyphenoloxidase (PPO) activity and on the total phenolic content of minimally processed (MP) apple (Malus domestica, cv. Jonagored) during cold storage was evaluated and a potential relationship with enzymatic browning was investigated. An ascorbic acid dip (42.6 mM) of 5 min duration was the most efficient chemical treatment in reducing the PPO activity of apple cubes. A 92% inhibition was achieved after 7 days of storage at 4C. All treatments were advantageous in comparison to the control in reducing color changes. Color changes, determined by absorbance at 420 nm (soluble pigments) and lightness (L) (insoluble pigments) of apple cubes treated with ascorbic acid were correlated with total phenolic content. No correlation was observed between PPO activity and tristimulus color parameters, browning index or total phenolic content of AA-treated apple cubes. [source] Thermal kinetics of color degradation of mulberry fruit extractMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 2 2003Hyung Joo Suh Abstract The effects of temperature and pH on color degradation kinetics of the mulberry fruit extract were investigated. The absorbance at 510 nm was decreased with increase of heating time, but that at 420 nm was increased with the increase of heating time at 100°C. The change of the browning index (A510/A420) was increased with increase of pH and was lower at pH 2.0 than that at pH 5.0. The browning index variation was adequately described by both the first-order and the zero-order kinetic. However, the zero-order kinetic model was proposed because of the better fit. According to the Arrhenius model, the activation energies for the browning index in the range of 80,100°C for the four different pH values were 30.68 kJ/mol for pH 2.0, 35.87 kJ/mol for pH 3.0, 42.67 kJ/mol for pH 4.0, and 43.49 kJ/mol for pH 5.0. 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