Moisture
of products is an important property for food scientists in food industry for
several reasons. It has effects on food quality, microbial stability, and food
processing operations. Microbial growth is directly related with moisture
content because water is vital for microorganisms. Moisture content also is
important for achieving quality standards. Moreover knowledge of moisture
content of food materials indicates type of processing operations.
 |
| Refractometer Scale |
Microorganisms
need water in an available form to grow in food products. The control of the
moisture content in foods is one of the oldest method to prevent from microbial
growth. Microorganisms respond differently to moisture content depending
on a number of factors. Microbial growth and the production of microbial
metabolites may be particularly sensitive to changes in moisture content.
Microorganisms generally have optimum and minimum levels of moisture content
for growth depending on other growth factors in their environments. Many
bacterial pathogens are controlled with moisture contents in the sample.
[1]. Moisture content helps determining of microbiological stability of
the food materials.
Texture
is one of the most important characteristics for the quality of food. Moisture
content has a determining effect on the evolution of important food properties,
such as texture, color and nutritional value. Controlling the initial moisture
content and its migration during storage is critical to the quality and safety
of foods. The packaging must provide a good moisture barrier, especially to
protect foods from excessive drying out, which adversely affects both texture
and taste. [2]
Moisture
content affects rheological properties of food product. This situation causes
operating different processes and different conditions in production lines such
as devices, pipes etc. Moreover there are some limitations and standards those
producers have to obey about moisture content. Some operations might be
required to achieve.
Total soluble solids content of a solution is
determined by the index of refraction. This is measured using a refractometer,
and is referred to as the degrees Brix. Brix is the term used when a
refractometer equipped with a scale, based on the relationship between
refractive indices at 20°C and the percentage by mass of total soluble solids
of a pure aqueous sucrose solution. This tests the solids concentration of a
sucrose containing solution. It is widely used during fruit and vegetable
processing to determine the concentration of sugar in the products. Sugar
concentration is expressed in degrees Brix. At 20°C, the Brix is usually
considered equivalent to the percentage of sucrose in the solution. The
measurement must be made at 20°C to get an accurate value. [3]
Ash is the inorganic residue remaining after
water and organic matter have been removed by heating. Total ash content
determination in foods provides a measure of total amount of minerals since
minerals are not destroyed by heating. The mineral content varies and depends
on many factors, such as the variety of wheat, the terrain, the fertilization,
and the climate. Moreover, it helps to estimate food’s quality microbial
stability and nutrition value.
REFERENCES
[1]Mossel
DAA, Corry JEL, Struijk CB, Baird RM. 1995. Essentials of the microbiology of
foods: a textbook for advanced studies. Chichester (England): John Wiley and
Sons. 699 p.
[2]Weinberg Z.G.,
Yan Y., Chen Y., Finkelman S., Ashbell G. & Navarro S. 2008. The effect of
moisture level on high-moisture maize (Zea mays L.) under hermetic storage
conditions-in vitro studies. Journal of Stored Products Research, 44(2),
136-144.
[3] FDA Sercice of
Regulatory Offices, (2005, September 10). Food Standards and Additives. ORa Laboratory Manual, IV-10, 18.
[4]
Hanson, J. (2003). Refractometry. Retrieved March 10, 2013 from
http://www2.ups.edu/faculty/hanson/labtechniques/refractometry/intro.htm
No comments:
Post a Comment