Final answer:
To find the fuel value in kJ of a 41-g serving, we calculate the Caloric content based on protein, carbohydrates, and fats, then convert Calories to kilojoules using 1 kcal = 4184 J.
Step-by-step explanation:
To calculate the fuel value in kJ for a 41-g serving, we need to understand the Caloric content per gram of the specific nutrients: protein, carbohydrates, and fats. These values are often provided on a food's nutrition label or source material. In general, each gram of protein and carbohydrates provides approximately 4.1 Calories, while each gram of fat provides 9.3 Calories. We then convert these Calories into kilojoules using the conversion factor 1 kcal = 4184 J.
For example, if a serving contains 10 g of carbohydrates, 5 g of protein, and 2 g of fat, the Caloric content would be:
- Carbohydrates: 10 g × 4.1 Cal/g = 41 Cal
- Protein: 5 g × 4.1 Cal/g = 20.5 Cal
- Fat: 2 g × 9.3 Cal/g = 18.6 Cal
Total Caloric content of the serving would be 41 + 20.5 + 18.6 = 80.1 Calories, which, after converting to kilojoules, results in:
80.1 Cal × 4.184 kJ/Cal = approximately 335.2 kJ