1. Irina Mladenoska*, Darko Dimitrovski
XXIV CONGRESS OF CHEMISTS AND TECHNOLOGISTS OF MACEDONIA
PRELIMINARY EVALUATION OF ANTIMICROBIAL ACTIVITY OF TABLE SALT, BASIL, CHILI PEPPERS AND MONOLAURIN USED AS ADDITIVES IN TOMATO SAUCE
Irina Mladenoska*, Darko Dimitrovski
Faculty of Technology and Metallurgy, University of Ss. „Cyril and Methodius“, Skopje, Republic of Macedonia
INTRODUCTION
The edible films and coatings are very popular nowadays in the preservation of fruits and vegetables, due to their compatibility with the minimal processing techniques. Those natural biopolymers appeared to be very suitable in preserving the freshness of fruits and vegetables, in deleing their deterioration, in lowering the respiration and the transpiration rate, and in lowering the rate of the mass loss. In this work both beeswax and sodium alginate were evaluated in their suitability to act as edible coatings for fresh mushrooms.
Tomato
Natural preservatives
Vacuum evaporator for preparation of tomato sauce
Solanum lycopersicum
Monolaurin - monoglyceride of lauric acid
Natural antimicrobial agent:
mother’s milk
Serenoa repens
Coconut oil
FDA-GRAS food additive
Cell wall
DNA
Ribosome
Antimicrobial activity of monolaurin
Kabara, J. J., Marshall, D. L. Medium-Chain Fatty Acids and Esters.
In: Davidson, P.M., Sofos, J.N., Branen, A.L. Antimicrobials in Food,
(pp ), CRC Press, Taylor & Francis Group, Boca Raton, USA, 2005.
Listeria monocytogenes
Staphylococcus aureus
Clostridium botulinum
Helicobacter pylorus
Aspergillus niger
Penicillium citrinum
Candida utilis
Saccharomyces cerevisiae
Ocimum basilicum
Fam. Lamiaceae
Rajesh K. Joshi. Chemical composition and antimicrobial activity of the essential oil of Ocimum basilicum L. (sweet basil) from Western Ghats of North West Karnataka, India. Anc. Sci .Life. 33 (3): 151–156, 2014
Franceli da Silva et al., Basil conservation affected by cropping season,
harvest time and storage period. Pesq. agropec. 40 (4), 2005
MATERIALS AND METHODS
The wild mould strains were isolated from apricot and tomato fruits in the Laboratory for Food Technology and Biotechnology, Faculty of Technology and Metallurgy, Skopje
The tomato sauce with 11% dry weight was prepared and divided in several portions, 100 mL each
Monolaurin (0.2 % w/v), basil (0.5 % w/v), chili peppers (0.5 % w/v ) and table salt (0.5 % w/v ) were added
The sealed glass containers with tomato sauce, each with different additive, were pasteurised
All samples were infected by 6 mL cell suspension (12x108cfu/mL) and incubated 3-4 days on 28 °C
Cell enumeration: standard plate counts (a number of colony forming units on a gram/mL sample) was calculated as follows: 25 mL sample was taken from each container, homogenized in 225 mL
sterile water, and solutions with different dilutions up to 10-7 were prepared. A mL from thus prepared solutions was converted to 3 Petri Dishes containing 12 mL solid Sabourand Dextrose agar. All the measurements were performed in triplicates with 3 different dilutions.
RESULTS
Appearance of the green mould (left) isolated from the rotten apricot (right)
RESULTS
The green mould isolated from the rotten apricot showed highest growth rate and was chosen for an infecting microorganism
Wild types of moulds isolated from: rotten tomato (left) and rotten apricot (right)
Cell enumeration (colony forming units)
Control
Monolaurin
Chili peppers
Basil
Cell enumeration showed that the basil spice and the monolaurin had an obvious antimicrobial activity when used as additives in tomato sauce
Microscopic appearance of the moulds isolated from: 1 (tomato-green mould), 2 (tomato-grey mould), 3 (apricot-green mould), 400 times enlarged
Growth of the fungus isolated from tomato sauce containing different additives:
control, chili peppers, monolaurin and basil.
The dilution of the samples used were 10-5, 10-6 and 10-7.
The tomato sauce containing monolaurin might be considered as a functional food, since it strengthens the immune system of the body
Some of the food additives might replace the conventional preservatives, thus double benefit can be achieved: lower concentration of chemical preservatives, healthier food, same degree of food safety
CONCLUSIONS
Further work in this particular research area is required
Tomato sauce type
Total cell count
(cfu/mLx105)
Monolaurin
15 ±1
Basil
9±1
Chili peppers
36±5
Salt
30±5
Control
38±5