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Keywords:

  • color;
  • C-value;
  • F-value;
  • numerical simulation;
  • size;
  • sous-vide;
  • texture

Abstract

The high-temperature sous-vide (HTSV) method was developed to prepare carrots with a soft texture at the appropriate degree of pasteurization. The effect of heating conditions, such as temperature and time, was investigated on various package sizes. Heating temperatures of 70, 80, and 90 °C and heating times of 10 and 20 min were used to evaluate the HTSV method. A 3-dimensional conduction model and numerical simulations were used to estimate the temperature distribution and the rate of heat transfer to samples with various geometries. Four different-sized packages were prepared by stacking carrot sticks of identical size (9.6 × 9.6 × 90 mm) in a row. The sizes of the packages used were as follows: (1) 9.6 × 86.4 × 90, (2) 19.2 × 163.2 × 90, (3) 28.8 × 86.4 × 90, and (4) 38.4 × 86.4 × 90 mm. Although only a moderate change in color (L*, a*, and b*) was observed following HTSV cooking, there was a significant decrease in carrot hardness. The geometry of the package and the heating conditions significantly influenced the degree of pasteurization and the final texture of the carrots. Numerical simulations successfully described the effect of geometry on samples at different heating conditions.

Practical Application

The high-temperature sous-vide (HTSV) method can be applied to produce pasteurized food ingredients for food service or companies producing processed food. A long processing time at a low temperature is traditionally used in the sous-vide method to maintain the characteristics associated with ingredient freshness, such as the hard texture of vegetables. Many fast food restaurants require ready-to-use ingredients that possess these characteristics and are microbiologically safe. Carrots used as ingredients in fast food meals require a fresh color and a soft texture. HTSV is a useful method to provide ready-to-use carrots as ingredients for fast food restaurants or processed food companies.