Chapter 6 lists equations how to calculate the heat penetration factor of such foods: first calculate the heat penetration factor of the container filled with brine only, and then add the calculated heat penetration factor of the largest solid piece of the food. Examples are beans in brine, sausages in brine, meat balls in gravy, etc. Several foods consist of solid food pieces, submerged in a liquid, or in a watery brine. Chapter 5 explains, by means of 2 worked examples, how to use this spreadsheet to estimate the fh of both a packaged liquid food and a packaged solid food. Excel spreadsheet “Heat penetration factor fh calculations.xls” simplifies the tedious calculations of the specific surface of a food container, required to find its heat penetration factor fh. For packaged solid foods, not the overall heat transfer coefficient U, but the thermal diffusivity a (many data in Annex 3), or the thermal conductivity k of the solid is required. A list with the estimated overall heat transfer coefficients U for all types of packaged liquid foods may be of help in rapid calculations of the heat penetration factor fh. Tables of the partial heat transfer coefficients for several types of retorts, food textures and packaging materials, and equations to calculate the overall heat transfer coefficient U, are presented in Chapter 4. Chapter 3 outlines the effects of the food packaging on the heat penetration factor fh: the material of the packaging (metal or glass) the shape of the packaging (cylindrical brick oval cube ball), and the packaging dimensions (length, height, width, etc), expressed as specific surface S (for a liquid food), or adapted squared specific surface S*^2 (for a solid food), are included in the equations of the fh. To use these tables, you need to know the product texture (solid or liquid), the packaging size (length L diameter D), the retort conditions (rotation or still retort) and the heating medium (saturated steam, showering water, or full water). From tables with fh values in Chapter 2, a first rough estimation can be made of the heat penetration factor fh of a food product, packaged in a cylindrical metal can. How this fh factor can be used in heat processing, is illustrated by a sterilization process calculation. Chapter 1 shows the basic equations to calculate the heat penetration factor fh of a packaged liquid or solid food. It presents the equations to calculate the fh, and lists formula to convert a known fh to the new fh after a change in processing or packaging conditions. For a quick reference, the second page gives an overview of the main factors which affect the heat penetration factor fh. Each explanation is illustrated with one or more worked examples. This document explains how to calculate, or estimate, the heat penetration factor fh. The heat penetration factor fh is crucial in calculating the pasteurization or the sterilization time of packaged foods.
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