Browning evaluation of ready-to-eat apples as affected by modified atmosphere packaging.

The color and polyphenol oxidase (PPO) activity of fresh-cut Golden delicious apples were evaluated throughout cold storage under modified atmospheres. The shelf life of cut apples was extended to several weeks, especially when an initial atmosphere of 90.5% N(2) + 7% CO(2) + 2.5% O(2) and plastic pouches of 30 cm(3)/cm(2) x bar x 24 h were used. Under these conditions, a maximum 62% PPO activity depletion was observed. In all cases, the faster the initial PPO activity decays, the less the color changes. A fractional conversion first-order model was proposed for predicting color changes in minimally processed apples. Browning was better described through lightness (L) (k(L) = 0.017 - 0.07 day(-1)) and color difference (Delta E*) values (k(Delta E) = 0.015 - 0.073 day(-1)), which fitted the model with enough accuracy.

Characterisation of low-fat high-dietary fibre frankfurters.

Two different peach dietary fibre (DF) suspensions (17 and 29%) were used to obtain low-fat high-DF frankfurters (20-5% fat) which were compared to an all-meat control (25% fat). The viscosity of the meat batters increased with DF content. The protein (11.5±0.6%) and collagen (1.4±0.1%) contents of frankfurters were not affected by DF addition, and the higher the DF content, the lower the pH (6.4 to 5.8) due to the fibre solution acidity. The DF was effective in retaining added water in low-fat frankfurters since their cooking losses were similar to those of the controls (5.5±0.1%). Low-fat frankfurters were darker and browner than the controls and only high fibre addition significantly decreased the textural parameters. Sensory evaluation indicated that low fat-high DF frankfurters (20, 15 and 10% fat) were as acceptable as the all-meat frankfurters.