Pasawadee Pradipasena

Development of non-water soluble, ductile mung bean starch based edible film with oxygen barrier and heat sealability

This research determined the effects of starch concentration (3.5-5.0%w/w), and plasticizer [glycerol (0-30%w/w) or sorbitol (0-60%w/w)] on properties of mung bean starch (MBS) films. The result showed that increasing plasticizer concentration tended to decrease tensile strength (TS), elastic modulus (EM) and oxygen permeability (OP); but increase elongation (%E), solubility, water vapor permeability (WVP) and seal strength. The extent of those changes also depended on starch concentration. Glycerol provided better plasticizer efficiency than sorbitol. A bimodal melting endotherm of retrograded structure was evident in non-plasticized film. However, only a low temperature endotherm was observed in polyol-plasticized films, indicating a plasticizer-induced structural modification. The developed ductile MBS films, (TS of 7.14±0.95 to 46.30±3.09MPa, %E of 2.46±0.21 to 56.95±4.34% and EM of 16.29±3.40 to 1428.45±148.72MPa) with an OP of 0.2397±0.0365 to 1.1520±0.1782 ccmm/m2daykPa and seal strength up to 422.36±7.93N/m, demonstrated in this study indicate the potential for food packaging applications.

Characteristics of Microparticulated Particles from Mung Bean Protein

Mung bean protein was separated from wastewater of mung bean starch factory by utilizing an isoelectric precipitation method. The characteristics of freeze dried protein concentrate (having 88.93% protein content on dry basis) were oil absorption capacity, water absorption capacity, surface hydrophobicity and emulsifying activity index of 5.76 g/g, 2.41 g/g, 30, and 83, respectively. The lab scale procedure for production of microparticulated protein particle (MP3) included heating 5% w/w solution of mung bean protein concentrate in deionized water at 83°C for 15 min, coupled with homogenization at 17,000 rpm, homogenization at 23,000 rpm for 15 min, and centrifugation at 1000 × g for 10 min. The resulting supernatant produced 0.89 g of 0.1–3.0 μm MP3 per g of dry mung bean protein concentrate. Observations of MP3 using SEM showed a particle round shape indicating the potential for MP3 to provide creamy texture in oil-in-water emulsion foods to serve as a fat replacer.

Physicochemical properties of thermal alkaline treated pigeonpea (Cajanus cajan L.) flour

Thermal alkaline treatment, normally used for corn, was applied to pigeonpea grains. Starch granules were isolated using wet milling and alkaline treatments. Effects of the calcium hydroxide [Ca(OH)2] concentration in the range of 0–1% (w/v) on granule structure, crystalline structure, chemical composition, and physicochemical, thermal, and pasting properties of isolated starch granules were determined. Compared to native samples, thermal alkaline treated samples had higher protein, lipid, calcium, and phosphorus contents, but lower starch and amylose contents. Thermal alkaline treatment increased starch granular size and gelatinization temperatures, but decreased relative crystallinity, gelatinization enthalpy, swelling power, solubility, amylose leaching, and the pasting viscosity. Amylose-lipid complexes were not found in thermal alkaline treated flours. As the Ca(OH)2 concentration increased, the amylose content, relative crystallinity, gelatinization temperature, and enthalpy also increased, but the swelling power, solubility, amylose leaching, and paste viscosity decreased. A higher Ca(OH)2 concentration produced more stable starch granules that resisted re-gelatinization.

Formation and characterization of BC and BC-paper pulp films for packaging application:

It was found beneficial to manufacture bacterial cellulose (BC) obtained from waste food sources to create value-added packaging products by firstly performing purification and disintegration processing of the BC and then reinforcing it with paper pulp. The purification treatment involved using sodium hydroxide (2% w/v at 100°C for 1 h) on BC pulp to remove the bacterial protein and the resulting cultured medium film was characterized with respect to its physical properties. An acid treatment on the purified BC pulp was applied to disintegrate cellulose network before forming a film. The results showed that the sodium hydroxide treatment increased the film burst index and brightness. Heating the BC pulp to 70–100°C in 1.25–5.00% v/v sulfuric acid treatment for 30 min degraded the film’s mechanical properties. Also, a study of the addition and mixing of paper pulps or modified cationic starch to the BC was found to improve the film properties with respect to packaging properties. Inclusion of short fiber paper pulp by 30 wt.% created a good synergistic effect by improving the mechanical properties of film especially for tear strength. Moreover, cationic-modified cassava starch (2% w/w) improved the tensile and burst index as well as resistance to oxygen permeation of the BC film. The results indicate that the BC pulp could be used to improve mechanical properties and resistance to water vapor and oxygen permeation of the short fiber paper pulp film which is ideal for packaging materials.