Effect of Pasteurization Temperature on Quality of Aonla Juice During Storage
The aonla fruit or Indian gooseberry comes from a small to medium size deciduous tree
native to India and contains 500 to 700 mg. of ascorbic acid per 100 g. of pulp, making it
one of the richest sources of Vitamin C. Aonla is highly nutritious and has therapeutic
qualities for treating the common cold, headaches and gastric troubles.[1] However, it has
limited table value because of its sour and astringent taste, but the fruits are processed
into products like preserves, candy pickles and juices.[2]
Aonla juice is one of those derivative liquids that contain plenty of micronutrients and
phytochemicals that enhance human function, structure and physiology and is promoted
to cure such medical conditions as high blood pressure and cholesterol levels and
rheumatism.[3]
Pasteurization refers to a process of heating liquid or solid food to a certain temperature
for a specific length of time and then immediately cooling the same, which would effect
the slowing of microbial growth in the food. The process aims to reduce the number of
pathogenic micro-organisms in the food to render them unlikely to cause disease.[4]
Flash pasteurization is the process of heating perishable beverages like fruit and
vegetable juices before putting them into containers in order to increase safety against
spoilage microorganisms and extend their shelf life, but must be used alongside sterile
fill technology. The process maintains better color and flavor in juices than other kinds
of pasteurization.[5] Flash pasteurization is the best preserver for berry juices and the
recommended temperatures are 80 degrees Centigrade or higher for 30 seconds.
The juice must fill bottles or cans to the fullest, after which the containers must be
immediately closed and cooled. Since juices high in nitrates affect some enamels in
cans, the latter need special enamel lining.[6]
Fruit juices are commonly prepared by squeezing or macerating fresh fruits without
applying heat or solvent.[7] Fruit juices deteriorate because of naturally occurring
enzyme activity, which makes the juice settle out and acid tolerant yeasts to grow,
leading to fermentation. To prevent these, the right temperature and duration of
heating must be established during pasteurization. The continuous rapid heating and
cooling of the juice must be closely controlled to produce juices efficiently, with
minimum loss of quality.[8]
The heat treatment in flash pasteurization minimizes flavor changes and is best fitted
for premium quality and natural-style juices. The economical aseptic packaging of
juices in flexible laminated multilayer plastic containers has been widely used globally
because the product can be stored at ambient temperature. In this case, the juice must
be heat pressurized, cooled and put into a pre-sterilized package under sterile
conditions. Such aseptically packaged juices placed at room temperature have 12
months of shelf-life.[9]
The use of common chemical preservatives like the potassium and sodium salts of
sorbic, benzoic and sulfurous acids in pure fruit juices is no longer widely permitted,
although a product with a juice drink label may allow preservative use in non-aseptic
packaging. Freezing can also preserve fruit juices, particularly in the transport and
storage of concentrated juices.[10]
However, based on a study, the pasteurization treatment also kills off the beneficial
bacteria in juices, alters the juices’ natural consistency when it separates its water and
sugar content and can compromise its nutritional value when it breaks down its
nutrients.
[1] Chhattisgarh State Medicinal Plant Board, “Pilot Project Proposal on Mission Aonla”, pdf,
<http://cgvanoushadhi.gov.in/anola.pdf> [accessed 12 May 2010]
[2] R. K. Goyal et al, “Osmotic Dehydration of Aonla”, World Scientific eProceedings, pdf abstract, 2011
<http://eproceedings.worldscinet.com/9789812771957/9789812771957_0153.html>
[accessed 12 May 2011]
[3] “Cure-All Juices: Indian Gooseberry (Amalaki)”, The Free Library, 2008,
<http://www.thefreelibrary.com/Cure-All+Juices%3a+Indian+Gooseberry+%28Amalaki%29-a01611725429> [accessed 12 May 2011]
[4] Sokoya Oluwatomi Temitayo, “Pasteurization in Fruit Juice”, OPPAPERS.COM, September 2010,
<http://www.oppapers.com/essays/Pasterization-In-Fruit-Juice/424026> [accessed 12 May 2010]
[5] “Flash Pasteurization”, Wikipedia, 8 March 2011, <http://en.wikipedia.org/wiki/Flash_pasteurization>
[accessed 12 May 2011]
[6] “Principles and Practices of Small- and Medium-Scale Fruit Juice Processing”,
FAO Corporate Document Repository, pdf, <http://www.fao.org/docrep/005/Y2515E/y2515e16.htm#P113_9960> [accessed 12 May 2011]
[7] “Juice”, Wikipedia, 9 May 2011, <http://en.wikipedia.org/wiki/Juice> [accessed 12 May 2011]
[8] “Tubular Pasteurizer for Fruit Juice”, Food and Nutrition Library,
<http://www.greenstone.org/greenstone3/nzdl?a=d&d=HASH011c1af96100e23ee05d58e7.7&c=fnl&sib=1&dt=&ec=&et=&p.a=b&p.s=ClassifierBrowse&p.sa=> [accessed 12 May 2011]
[9] “Fruit Juices”, Scribd, <http://www.scribd.com/doc/30116533/Fruit-Juices> [accessed 12 May 2011]
[10] ibid
Credit:ivythesis.typepad.com
0 comments:
Post a Comment