Food Analysis Exam 3

5 major components of food

water, protein, fat, carbs, ash (minerals)

minor components of food examples

vitamins, natural products (polyphenols, terpenes, alkaloids), flavor compounds, acids

proximate analysis

% of each 5 of the major components of food

100% food = %water + %fat + % protein + %carbohydrates + %ash

how to calculate carbs

% carbohydrate= 100% - (%water +%fat +% protein +% ash)

proximate analysis gives idea of major

chemical components of food

wet weight basis

% moisture or solids in whole food

% moisture wwb

g water/ g total sample

% solids wwb

g solids/ g total sample

dry weigh basis

% moisture or % solids in dry weight only

why would you use dry weight basis

normalizes for water and allows for direct comparison between samples

% moisture dry weight basis

g water/ g total solid

% solids dry weight basis

g component of interest/ g total solids

why is moisture content important

• standards of identity

• food processing

• product quality

• shipping costs

• quality and value of ingredients

• microbial safety

physical methods of measuring moisture

oven, distillation, hydrometer, refractometer, freezing point

chemical methods of measuring moisture

Karl Fisher Method

most common drying method

oven drying

steps of oven drying

1. weigh empty aluminum pan

2. weigh sample in pre-weighed pan

3. dry in oven

challenges with oven drying

• surface crust may form (prevent by mixing with pre-weighed sand)

• spattering may occur

how convection oven works

hot air circulates in oven without aid of fan

convection oven ideal use

simple samples with low carb content

how forced draft drying works

fans create forced drafts to circulate air within the oven

ideal use of forced draft fan

large number of low CHO samples

how vacuum drying works

vacuum reduces pressure, heating element heats sample

ideal use of vacuum drying

high sugar samples

how automated drying works

sample dried until weight is stable, moisture calculated automatically

automated drying ideal use

dry or intermediate moisture products