Characterization of local sweet potato starch-based films at different varieties : vitato and anggun

Romzi, Nur Alia Syafiqah (2019) Characterization of local sweet potato starch-based films at different varieties : vitato and anggun. [Project Paper] (Submitted)

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Abstract

The aim of this study is to prepare and characterize sweet potato starch-based films at different varieties particularly VitAto and Anggun on the physical, mechanical and thermal properties as well as antimicrobial activity. The starch from these two varieties was extracted from the sweet potato and ground into powder in order to be used for film making. The sweet potato starch (SPS) films were prepared by casting technique followed by drying the films at room temperature for 48 hour. The VitAto SPS films showed higher brightness (L*) and lower a* and b*value. These results are vice versa for Anggun SPS films that demonstrated low brightness (L*) and high a* and b* value. Furthermore, the VitAto SPS films possessed lower solubility in the water than the Anggun SPs films. The films were then prepared with the addition of different types and concentrations of plasticizer particularly glycerol and sorbitol at 15% and 30% loadings. The addition of plasticizer into the films significantly alter the properties of SPS films for both varieties. The presence of glycerol and sorbitol at concentrations of 15% in the VitAto SPS films demonstrated a better mechanical and thermal properties than Anggun SPS films. Moreover, the glycerol-plasticized films showed lower tensile strength (TS) and higher elongation at break (EaB) particularly at 15% loading and the films exhibited anti-plasticizing effect toward the SPS films for both varieties at higher loading of plasticizers (30% loading). In addition, the physical, mechanical and antimicrobial properties of SPS films containing natural agent (i.e. thymol) as an antimicrobial agent at a fixed %% concentration were investigated. The addition of thymol influenced the physical, mechanical and thermal properties of the films. The presence of thymol in the SPS films increased the solubility of films in the water as well as reduced the TS and increased the EaB up to 90%. The result demonstrated that thymol was able to be released from the SPS films and inhibit the growth of gram-positive and gram-negative bacteria such as B. subtilis and E. coli respectively. These findings were supported by the turbidity test on the antimicrobial activity of the films. Besides, this research is also aim to utilize the waste from sweet potato peel (SPP) for the production of starch-based films. The results demonstrated the peel form the sweet potato has the potential to form a film with the combination of SPS. Interestingly, up to 50% of waste (SPP) can be incorporated into the starch and perform good film properties. In this study, the best ratio of sweet potato starch to peel was 5:5 (in gram). The colour of SPS/SPP films was a little bit darker and more opaque than the SPS films. The SPS/SPP films also was more soluble than SPS films.

Item Type:	Project Paper
Faculty:	Faculty of Engineering
Depositing User:	Ms. AZLINA ZAINAL ABIDIN
Date Deposited:	21 Nov 2024 04:42
Last Modified:	21 Nov 2024 04:42
URI:	http://psaspb.upm.edu.my/id/eprint/2221

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