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35 Edible Coatings and Films from Agricultural and Marine Food Wastes

barrier and mechanical properties due to their polar (hydrophilic) nature. So,

there is a need to focus on the development of new strategies for enhancing the

characteristic properties of biopolymers to meet the food packaging requirements,

in particular, high water vapor barrier and mechanical properties. These strategies

might involve the chemical modification, incorporation of firming agents or other

additives, and utilization of nanoparticles that provide the functionalities which

were lacking in the original film [9].

Fruit pomace mainly consists of cellulose and pectin. These are the primary

polysaccharides present in the cell wall, which determine the integrity and rigidity

of the tissue. The composition ranges vary from fruit to fruit and also on the

fruit varieties. Agricultural and food industrial by-products mainly constitute

fruit pomaces from apple, sugar beet pulp, citrus, and so on, which are rich in

pectin and antioxidant substances. The only drawback of fruit pomace is low

solubility [12]. Utilization of the fruit peel in the film development showed a good

characteristic property as the peel contains a good composition of nutrients like

carbohydrates and protein and also rich in pectin. The industrial extraction for

pectin mainly utilizes apple pomace or citrus peel. Pectin-based film shows a good

mechanical property. Banana flour films rich in pectin formed with slight yellow

appearance and transparency. The film showed a good mechanical and oxygen

barrier properties and sealability [18].

Borah et al. [19] developed a composite film by varying the concentration of potato

peel and sweet lime pomace, with an ultrasound treatment. On studying their char-

acteristic properties, the results shown that the film made in the ratio of 0.5 : 1 have

given the best result and a good quality of bread on storage of five days.

In the development of composite film, strong interfacial action needed among the

components was used. A study was done by Briones et al. [20] on utilizing the lique-

fied agricultural residues such as corn stover, corncob, vine shoot, and blueberry tree

pruning for making films. These are rich in lignocellulose and incorporated in to the

starch-glycerol film. This film showed a good compatibility and exhibited the better

thermal stability and dynamic mechanical properties than the control starch film.

In a study done by Andrade et al. [6], the author developed an edible film using the

fruit and vegetable residual flour (FVR), without the plasticizer addition. The flour

mainly includes residue from passion fruit, carrot, watermelon, lettuce, taro, cucum-

ber, rocket, selecta orange, courgetti, mint, and spinach. And the film is made with

two proportions, i.e. with 10% and 8% of the flour and the 8% sample contains 2%

of potato peel. Incorporation of potato peel resulted in enhanced tensile strength.

The film containing the high carbohydrate content showed good flexibility than the

starch-based edible film.

35.3.2

Biopolymers from Grain Wastage

Cereal wastages from rice, wheat, rye, barely, and corn are the good sources for

proteins. The wastage is obtained after processing, polishing, washing, grinding, or

refining of the grains. Recent studies have shown the development of edible film

and coating by the application of protein from the pulse wastage which provided an