Using chitosan, an emerging ingredient extracted from fungi
cell walls, may act as an anti-microbial ingredient for orange
juice, and remove the need for pasteurization, says a new
Adding one gram of chitosan to one litre of fresh orange
juice was found to reduce both enzymatic and non-enzymatic
browning of the juice, while also controlling the spoilage
during the storage time, according to new findings published
in Innovative Food Science and Emerging Technologies.
The research taps into an ever-growing body of study exploring
novel source of natural alternatives to synthetic preservatives,
such as like BHA and butylhydroxytoluene (BHT), to slow down
the oxidative deterioration of food is gaining interest.
At present, 'natural' is a powerful force in the food industry,
and there is increasing resistance at regulatory and consumer
level - as well as from food retailers and manufacturers aiming
to meet their demands - to synthetic preservatives.
The study also provides an alternative approach to pasteurization,
said the researchers, following concerns raised by the US
Food and Drug Administration (FDA) to avoid consumption of
un-pasteurised orange juice due to fears of potential contamination
with Salmonella Typhimurium.
The researchers, led by Ana Mart?n-Diana from the Postharvest
Technology Unit (PTU) and Functional Ingredient Food Unit
(FiFu) at the Dublin Institute of Technology (DIT), enriched
orange juice with chitosan in concentrations ranging from
0 to 2 grams per litre of juice.
Addition of chitosan, produced by the deacetylation of chitin
- a natural non-digestible polysaccharide found in the cell
walls of fungi and the exoskeletons of insects was
found to reduce the counts of bacteria, and reduce the browning
of the juice.
However, while chitosan concentrations over 1 gram per litre
favourably impacted the quality, they adversely affected the
vitamin C content of the juice, as well as increasing the
bitterness of the juice, said the researchers.
The study recommends the use of chitosan at concentrations
up to 1 gram per litre to extend quality and preserve ascorbic
acid and carotenoids during storage time of fresh orange juice,
thus avoiding the use of standard thermal treatments which
produce a negative impact on the nutritional value,
Always room for further study
The researchers noted that additional study is required,
and should include investigating how the deacetylation degree
of chitosan affected the degree of preservation of the juice.
Additional microbiological studies should also help clarify
the efficacy of chitosan as a natural preservative for
orange juice, they concluded.