Energy Carbohydrates Fats Proteins

Overview

Engineering reference data for Energy Carbohydrates Fats Proteins in food bio.

Key Formulas

pH

$pH = -\log_{10}[H^+]$

Measure of acidity in food.

Water Activity

$a_w = \frac{P}{P_0}$

Ratio of vapor pressure of food to pure water.

Thermal Death Time

$\log\frac{N_0}{N} = \frac{t}{D}$

Microbial reduction during heating.

Q10 Temperature Coefficient

$Q_{10} = \left(\frac{k_2}{k_1}\right)^{10/(T_2-T_1)}$

Rate change per 10°C temperature increase.

Variables

Symbol	Description	Unit
$pH$	Acidity level	—
$a_w$	Water activity	—
$N$	Microbial count	CFU
$D$	Decimal reduction time	min
$Q_{10}$	Temperature coefficient	—

Energy Content Data

The table below summarizes the specific energy content for major macronutrients, which is fundamental for nutritional calculations and food energy analysis.

Conversion Notes

The values represent the average metabolizable energy per unit mass. The common approximation for food energy is:

• 4 kcal/g for carbohydrates and proteins.
• 9 kcal/g for fats. These values are critical for calculating the total energy content of a food item from its macronutrient composition.

Interactive Charts

References

• Original Source