Abstract: Xanthan gum is one of the major commercial
biopolymers. Due to its excellent rheological properties xanthan gum
is used in many applications, mainly in food industry. Commercial
production of xanthan gum uses glucose as the carbon substrate;
consequently the price of xanthan production is high. One of the
ways to decrease xanthan price, is using cheaper substrate like
agricultural wastes. Iran is one of the biggest date producer countries.
However approximately 50% of date production is wasted annually.
The goal of this study is to produce xanthan gum from waste date
using Xanthomonas campestris PTCC1473 by submerged
fermentation. In this study the effect of three variables including
phosphor and nitrogen amount and agitation rate in three levels using
response surface methodology (RSM) has been studied. Results
achieved from statistical analysis Design Expert 7.0.0 software
showed that xanthan increased with increasing level of phosphor.
Low level of nitrogen leaded to higher xanthan production. Xanthan
amount, increasing agitation had positive influence. The statistical
model identified the optimum conditions nitrogen amount=3.15g/l,
phosphor amount=5.03 g/l and agitation=394.8 rpm for xanthan. To
model validation, experiments in optimum conditions for xanthan
gum were carried out. The mean of result for xanthan was 6.72±0.26.
The result was closed to the predicted value by using RSM.
Abstract: This study was conducted to evaluate the antifungal
activities of Cinnamomum zeylanicum and Origanum vulgare L.
essential oil against Aspergillus flavus in culture media and tomato
paste. 200 ppm of cinnamon and 500 ppm of oregano completely
inhibited A. flavus growth in culture media, while in tomato paste 300
ppm of cinnamon and 200 ppm of oregano had the same effect. Test
panel evaluations revealed that samples with 100 and 200 ppm
cinnamon were acceptable. The results may suggest the potential use
of Cinnamomum zeylanicum essential oil as natural preservative in
tomato paste.