Home About us Contact
|
Home About us Contact | ||
|
|
||
Ascorbic Acid Degradation (ascorbic + acid_degradation)
Selected AbstractsDegradative 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] EFFECT OF ANTICAKING AGENT ADDITION AND HEADSPACE REDUCTION IN THE POWDERED-DRINK MIX SENSORY STABILITYJOURNAL OF FOOD QUALITY, Issue 3 2006INAR A. CASTRO ABSTRACT The objective of the present study was to assess the effect of the addition of 0.2% anticaking agent "silicon dioxide" (S) and of 70.0% reduction of the headspace in the package (H) both individually and combined (SH), on the sensory and physicochemical characteristics of a powdered-drink mix over a shelf-life period of 120 days. The "difference from control" test was applied to 10 trained panelists in order to assess the four treatments at 30-day intervals throughout the experimental period, according to visual aspect of the powdered mix and drink flavor. The results demonstrated that a reduction of 70% of the headspace was the most effective treatment for product sensory stability. Water activity (Aw) was a more sensitive parameter than moisture content and ascorbic acid degradation. Although Aw has shown a significant difference over time, the sensory properties still seemed to be a better shelf-life indicator for powdered mixes. Based on the sensory alterations of the aspect of the powder, a reduction of headspace and the limiting of shelf life to between 60 and 90 days could be recommended for powdered-drink mixes packaged in polypropylene containers. [source] A study on degradation kinetics of ascorbic acid in drumstick (Moringa olifera) leaves during cookingJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2005Nisha P Bineesh Abstract The kinetics of ascorbic acid degradation in drumstick (Moringa olifera) leaves as well as in pure ascorbic acid solutions at the initial concentrations present in drumstick leaves over a temperature range of 50,120 °C (isothermal temperature process) has been studied. The degradation kinetics of ascorbic acid was also evaluated in normal open-pan cooking, pressure-cooking and a newly developed and patented fuel-efficient eco cooker (non-isothermal heating process). The ascorbic acid degradation followed first-order reaction kinetics where the rate constant increased with an increase in the temperature. The temperature dependence of degradation was adequately modelled by the Arrhenius equation. A mathematical model was developed using the isothermal kinetic parameters obtained to predict the losses of ascorbic acid from the time,temperature data of the non-isothermal heating/processing method. The results obtained indicate the ascorbic acid degradation is of similar order of magnitude in all the methods of cooking. Copyright © 2005 Society of Chemical Industry [source] Comparison of the Stability of Pelargonidin-based Anthocyanins in Strawberry Juice and ConcentrateJOURNAL OF FOOD SCIENCE, Issue 4 2002G.A. Garzón ABSTRACT Strawberries were processed into juice (8° Brix) and concentrate (65° Brix) and different lots were fortified with pelargonidin 3-glucoside, pelargonidin 3-sophoroside, and acylated pelargonidin 3-sophoroside 5-glucoside. Changes in pigment concentration, color (CIE L*a*b*) and ascorbic acid content were monitored during storage at 25 °C. Anthocyanin and ascorbic acid degradations followed 1st order reaction kinetics. Fortification increased the half-life of the pigments from 3.5 to 5 d in concentrate and from 5 to 12 d in juice. The half-life of ascorbic acid was 2 d in juice samples and ranged from 3 to 10 d in concentrate samples. Both systems showed changes in chroma and hue angle, but maintained L* values. [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] | ||||||||||