Current and Innovative Packaging Technologies for Tropical and Subtropical Fruits - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 123

5

4.5

4

3.5

3

K(LDPE) = 0.057

2.5

2

1.5

1

LDPE Film

K(Film) = 0.17

0.5

Prototyping Film

0

0 10 20 30 40 50 60 70 80 90 100

Time (hr)

Figure 7.7. Ethylene concentration inside the bag of composite film and commercial low-density polyethylene
(LDPE) film (initial concentration was 4 ppm) (reprinted with permission from Fuongfuchat et al., 2008).

CO 2 permeability (Sirikittikul et al., 2008). Developed high
ethylene-permeable bags (EP) by this research group were
tested on acetylene treated mature green banana (Klintham
et al., 2010). It was found that ethylene-permeable bags
slowed down ripening process of banana and prolong shelf
life to 14-17 days. Bananas stored in air, at 13 ◦ Chada
shelf life of 5-8 days, and bananas in BOPP and LDPE
bags had a shelf life of 4 days. High oxygen permeable film
also exhibited a positive result on extended shelf life; how-
ever, low ethylene accumulation of 0.4 ppm was measured
in high ethylene-permeable bags.

coatings can be produced from three major types of biopoly-
mers, including polysaccharides (carbohydrates and gums),
proteins and lipids (Lin and Zhao, 2007), and food-grade
additives such as plasticizers. Research efforts over several
decades have continued in studying and developing edible
films and coatings for food products, which were exten-
sively published and reviewed (Kester and Fennema, 1986;
Han, 2005; Han and Gennadios, 2005).
Previous studies on edible coatings for tropical fruits
include potato starch-based coatings for guava (Quezada
Gallo et al., 2003), edible coating for preserving kiwifruit
at ambient temperature (Xu et al., 2001), chitosan films and
coatings for mangoes (Srinivasa et al., 2002; Chien et al.,
2007; Dang et al., 2008), and coatings of carboxymethycel-
lulose containing maltodextrin for retaining visual quality
and flavor of fresh-cut mango (Plotto et al., 2004). Other
major endeavors in this field also involve developing effec-
tive edible films and coatings for fresh fruits from a new
material and/or new approach of film formation (such as
blended or composite films) as well as experimenting the
use of fruits/vegetable purees as the edible films (McHugh
et al., 1996; Sothornvit and Rodsamran, 2007).
Besides permeability and mechanical integrity, wettabil-
ity is another key factor to ensure effective film products,
whereas all these factors should be optimized. Effective

Edible coatings/films
Edible films and coatings can be considered one class of ac-
tive packaging technology, owing to the extra functions of
the edibility and biodegradability of the films and coatings
(Han, 2002), and/or additional functions of the films and
coatings besides the ordinary barrier against oil, gas, and
water vapor. Edible films and coating have generally been
used to prevent moisture loss, improve appearance, and ex-
tend shelf life of fruits. Additional functions can arise from
the use of edible films/coatings as carriers of active addi-
tives or substances such as antimicrobials, antioxidants, fla-
vors, and colors (Krochta and De Mulder-Johnston, 1997;
Han and Gennadios, 2005). In general, edible films and