Scientists from the National Institute of Food Science & Technology, (NIFSAT) University of Agriculture, Faisalabad (UAF) tested edible coatings on strawberries, apples, mangoes and apricots.
Under the supervision of principal investigator, Dr. Masood Sadiq Butt, researchers worked to extend the shelf life of the different fruits with different coatings.
The work entitled: “Developing and exploring the role of edible coatings to improve the quality and shelf life of whole and minimally processed fruits”, was funded by the Higher Education Commission of Pakistan (HEC).
Types of coatings
In the trials, carbohydrate based coatings (chitosan, alginate and starch) and protein based coatings (soy and whey) were developed and applied to fruits.
Treated fruits were kept at refrigeration temperature with controlled relative humidity and periodically evaluated for various physicochemical and sensory attributes during storage.
Dr. Masood Sadiq Butt told FoodProductionDaily.com it was a very economical technology for developing and fully developed nations.
“The next step is looking for a collaboration to develop the project outside of Pakistan as food producers can safely export abroad using this research.
“It is interesting for the world to know you can extend shelf life of food and cut down on the food waste. It means more items can be exported as they last longer.”
Different physicochemical analyses like weight and moisture loss, pH, acidity, total soluble solids, vitamin C and colour were evaluated.
He added: “The technology is possible on vegetables such as cucumber and carrot, one of my students did work on this and found it extends the shelf life.
“We didn’t expect so long results, the six week limit we have given is just to be on the safe side and we are currently experimenting with temperature and humidity.
“There is a possibility of other coatings, we are looking at ones such as a gluten-based coating.”
How it works
Edible coating preservation is generated by stimulating the epidermal structure and wax layer of different fruits with improved production performance.
Appropriate amounts of the coating form a thin porous membrane on the fruit surface reduces the respiration, decreases evaporation of water and prevents the invasion of micro-organisms.
It also delays dehydration, inhibits the volatilization of aromatic substance, improves texture and extends shelf life of the fruits.
Sensory evaluation was conducted to assess product on colour, flavour, firmness and taste ratings.
Results showed for strawberry, alginate and soy coatings performed better, extending the shelf life for about two weeks.
For apricot, chitosan, alginate and soy based coatings managed to have better performance in extending the shelf life up to six weeks.
In apple, all the coating formulations were quite effective in maintaining its quality characteristics for seven weeks, except the whey based edible coating.
Mango was minimally processed and the resultant dices were coated with chitosan and alginate coatings, which were most effective in their response with reduced moisture and weight loss.