Storage stability of chilled minimally processed shredded cabbage
Minimally processed products are a rapidly growing segment for retail market and food service horticultural industry as they match the consumers' demand for product freshness and convenience. The shelf-life extension of these fresh-cut products is therefore relevant because of its economic i...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2003
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/8728/1/FSMB_2003_21%20IR.pdf |
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| Summary: | Minimally processed products are a rapidly growing segment for retail market
and food service horticultural industry as they match the consumers' demand for
product freshness and convenience. The shelf-life extension of these fresh-cut
products is therefore relevant because of its economic impact. Packaging can be one
of the important factors in determining the storage stability and quality of these freshcut
products. The shelf life of minimally processed fruits and vegetables is often
limited by enzymatic browning. The organoleptic properties of fruits and vegetables
are strongly altered by the appearance of brown pigments. This study was conducted
to determine the effects of using different types of polymeric films (Polypropylene
(PP), Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE) and
PVC cling wrap (Control» of varying permeabilities to gases and water vapour and
also with and without the application of vacuum packaging on the physico-chemical,
biochemical, microbiological characteristics and sensory aspects of the minimally
processed (MP) shredded cabbage during storage at 5±loC; 90-95% RH. A study was also conducted on the effects of dipping into 4 different anti-browning solutions
namely 1% ascorbic acid, 0.1% sodium metabisulphite, 0.5% L-cysteine + 0.1% citric
acid and 0.1% acetic acid on the storage stability of shredded cabbage. Sample dipped
in distilled water was used as a control. Physico-chemical characteristics were
determined by quantitative measurements of weight loss, colour, texture, ascorbic
acid content, pH, titratable acidity, total soluble solid, chlorophyll content, polyphenol
oxidase (PPO) activity and degree of browning. Carbon dioxide and ethylene
production in the package atmosphere during storage were also determined with gas
chromatography. The microbial characteristics determined were mesophilic and
psychrotrophic bacterial counts and mold and yeast counts. Sensory evaluation
involved subjective acceptability and descriptive analyses. Data collected were
analyzed using ANOVA and Duncan Multiple Range Test (DMRT) at 5% significant
level. Generally, in almost all the analyses done, the quality of the MP shredded
cabbage deteriorated with increase in storage time. Among all the packaging films
used, it was found that PP which is the least permeable film for gases and water
vapour, could extend the shelf life of the MP shredded cabbage almost up to 3 weeks
with minimum colour change, reduction in ascorbic acid content and deterioration in
sensory properties, and marginally low changes in other parameters tested. Whilst
PVC cling wrap (control) was found to be the least effective packaging film. Different
packaging systems did not affect the microflora of the shredded cabbage which was
predominantly bacteria, small numbers of yeasts and only an occasional mold for both
mesophilic and psychrotrophic microorganisms. Samples packed in vacuum
packaging showed no significance difference with those in non-vacuum packaging in
almost all the parameters tested for all the different packaging films, even though the
air from the package headspace which can cause oxidation spoilage to the produce had been removed. Anti-browning treatment of 0.1% sodium metabisulphite gave the
best sensory properties and visual colour retention followed by 0.1% acetic acid
solution. Mean while 0.5% L-cysteine + 0.1% citric acid and 1% ascorbic acid
solutions were found to be not very good anti-browning agents for the MP shredded
cabbage as they gave worse results compared to control. |
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