The preparation of water resistance and antimicrobial edible film by electrospinning technology

• Main Authors: XIAO, RI-JUN, 蕭日君
• Other Authors: CHEN, HUI-HUANG
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/y39djb

碩士 === 國立宜蘭大學 === 食品科學系碩士班 === 106 === Gelatin, with thermal soluble and cold gelation, is a desirable material to produce thermal soluble edible films. However, the edible film prepared with gelatin exhibited high hydrophilicity and rich nitrogen source, which is beneficial to absorb of vapor in environment or moisture in foods and cause the followed microbial growth that will lose the protection ability of packing. Electrospinning is a novel technique for food coating and can produce sub-micron or nano size droplets or fiber, which giving its potential to form very thin and uniform coatings. In this study, shellac and chitosan were electrospun on gelatin film, in order to improve the water resistance of the film, and by the aid of sorbic acid to achieve the antibacterial and antifungal ability to improve storage properties of the edible film under ambient temperature. The results indicated that the electrospinning solutions prepared with 1%3% low molecular weight chitosan dissolved in 90% acetic acid (viscosity 158.44164.7 cP) are difficult to electrospun to form fiber. Therefore, chitosan was electrosprayed in bead patterns, and 2% low molecular weight (5.0×104−1.9×105 g/mol) chitosan can form uniformly spread droplets on gelatin film. The film coated with electrosprayed shellac (Sh/G) and then electrosprayed 2% chitosan for 1.5 h (C/Sh/G) can reduced the relative water uptake from 14.68% to 12.87%, and keep same hot water solubility as Sh/G. The higher than 97% inhibition percentage against Escherichia coli and Staphylococcus aureus were obtained for the film coated with electrosprayed chitosan (C/G), chitosan/shellac (C/Sh/G), but no antifungal effective was observed. For sorbic acid combination tests, sorbic acid lost during electrospraying and reduced the effect of inhibiting the growth of Aspergillus brasiliensis. Therefore, sorbic acid (0.6% of gelatin weight) was added to gelatin film (G-SA), which can completely inhibited A. brasiliensis growth and reduced E. coli to < 1 CFU/16 cm2, but only 1.3 log CFU/16 cm2 S. aureus was inhibited. The S. aureus could be inhibited to < 1 CFU /16 cm2 when chitosan/shellac was electrosprayed on G-SA (C/Sh/G-SA). This phenomenon exhibited that the synergistical inhibition against S. aureus existed between sorbic acid and chitosan. The relative water uptake and hot water solubility of C/Sh/G-SA are 12.58% and 87.87% respectively. No microbial growth for C/Sh/G-SA was stored at 30oC for 21 days. These results revealed that the C/Sh/G-SA edible film possesses water resistant ability and antimicrobial activity which is conducive to the preservation of edible film.