الفهرس 
Definition and Functionality of edible films and coatingOnly 14 pages are availabe for public view
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Abstract
The goals of this study were to investigate the characteristics
(physiochemical, mechanical and barrier properties) of functional edible
films prepared from different types of cow’s or buffalo’s milk protein
using different plasticizer (glycerol or sorbitol). Moreover, our study also
carried out to investigate the possibility of using total milk proteinates
(TMP) edible film containing some preservatives as a dipping or
packaging in Ras cheese during ripening and its effect on the
characteristics of cheese quality. The study was conducted in two parts,
the first part, eight different types of milk proteins (acid casein, rennet
casein, casein co-precipitate and total milk proteinates) were prepared
from cow’s and buffalo’s milk. These proteins were used as polymers to
form sixteen edible film samples using different types of plasticizers
(glycerol or sorbitol). The result edible films were evaluated
physiochemically, mechanically and for their barrier properties. The
results indicated that the type of protein polymer and plasticizer used in
edible film formation had significant effect on its physiochemical,
mechanical and barrier values. Different edible films plasticized by
glycerol were higher in moisture content, swelling, water solubility,
elasticity, water vapor and gas permeability values, while lower in
thickness, tensile strength and elastic modulus values compared with the
different edible films plasticized by sorbitol. No significant differences
were observed in all physiochemical, mechanical and barrier properties
values between different edible films prepared from different cow’s
proteins and films formed using different buffalo’s proteins. It could be
concluded that, all types of milk proteins especially total milk proteinates
(TMP) prepared from cow’s or buffalo’s milk could be used as a suitable
polymer for prepare edible film with good physiochemical, mechanical
and barrier properties.
In the second part, eight Ras cheese samples were manufactured
and dipped or packaged by different types of edible coating solutions or
films prepared from buffalo’s total milk protein (TMP), some of which
containing different preservatives. Control Ras cheese were neither
dipped nor packaged with any film or wax, while one of other cheese
treatment was coated by paraffin wax. The other treatments were either
dipped or packaged whether with TMP containing or not preservatives,
namely 0.1% of mixture of nisin+natamycin (1:1) or potassium
sorbate+natamycin at the same level and ratio.
The obtained results revealed that, the coating of Ras cheese with
TMP edible film led relatively to reduce the rate of cheese moisture loss
and hence the salt in water phase remained in the ranges those encouraged
the growth of lactic acid bacteria to develop more acidity and hence
enhanced the ripening rate as explained from the determined ripening
indices (Soluble nitrogen and Total volatile fatty acids). That has indeed
reflected in the relative cheese weight stability during ripening. The
presence of preservatives in the film kept cheese under microbiological
control according to the yeast and moulds count. Organoleptically, the
cheese coated with TMP persevered with potassium sorbate+natamycin
whether by dipping or packaging gained the highest sensory scores.
The forgoing results led to conclude that, Ras cheese could be
hold its weight during ripening period besides improve its marketing
quality when coated with edible film based on milk protein especially
persevered with 0.1 % of mixture of potassium sorbate+natamycin (1:1).
Key words: milk protein, edible film, functional properties, dipping Ras
cheese, packaging Ras cheese.