Lecture # 3. MOISTURE. Moisture Analysis. Introduction Importance of moisture analysis Forms of water in foods Moisture content of foods Oven drying methods Temperature control Types of oven Distillation Procedures Chemical Method Physical Methods. Introduction.
1- Moisture is a quality factor in the preservation of some products and affects stability in
2- Moisture is used as a quality factor for
4- Moisture (or solids) content is often specified in compositional standards (i.e., Standards of Identity)
6- Moisture data are used to express results of other analytical determinations on a uniform basis (i.e., dry weight basis).
1)-Dry oven method
there are many types of oven:
1- Liquid products (e.g., juices, milk) are commonly prettied over a steam bath before drying in an oven.
2- Products such as bread and field dried grain are often air dried, then ground and oven dried, with the moisture content calculated from moisture loss at both air and oven drying steps.
1- Particle size
2- Particle size distribution
3- Sample sizes
4- Surface area during drying
Usually used with liquid dairy products, nuts.
Should not be used with high carbohydrates sample
Drying time 0.75-24 hr
draying under reduced pressure
used with high carbohydrates sample
Fast, accurate method of analysis
Forced ventilation to remove moisture
Drying time 10-25 min
Used widely from the food industries because it is fast, accurate, and easy.
Codistilling the moisture in a food
sample with a high boiling point (direct & reflux)